diff --git a/lib/python3.12/site-packages/sympy/physics/control/__init__.py b/lib/python3.12/site-packages/sympy/physics/control/__init__.py new file mode 100644 index 0000000000000000000000000000000000000000..fb8c13ff147b3603466c8c4b2d9c8c0b25e3b360 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/control/__init__.py @@ -0,0 +1,16 @@ +from .lti import (TransferFunction, Series, MIMOSeries, Parallel, MIMOParallel, + Feedback, MIMOFeedback, TransferFunctionMatrix, StateSpace, gbt, bilinear, forward_diff, + backward_diff, phase_margin, gain_margin) +from .control_plots import (pole_zero_numerical_data, pole_zero_plot, step_response_numerical_data, + step_response_plot, impulse_response_numerical_data, impulse_response_plot, ramp_response_numerical_data, + ramp_response_plot, bode_magnitude_numerical_data, bode_phase_numerical_data, bode_magnitude_plot, + bode_phase_plot, bode_plot) + +__all__ = ['TransferFunction', 'Series', 'MIMOSeries', 'Parallel', + 'MIMOParallel', 'Feedback', 'MIMOFeedback', 'TransferFunctionMatrix', 'StateSpace', + 'gbt', 'bilinear', 'forward_diff', 'backward_diff', 'phase_margin', 'gain_margin', + 'pole_zero_numerical_data', 'pole_zero_plot', 'step_response_numerical_data', + 'step_response_plot', 'impulse_response_numerical_data', 'impulse_response_plot', + 'ramp_response_numerical_data', 'ramp_response_plot', + 'bode_magnitude_numerical_data', 'bode_phase_numerical_data', + 'bode_magnitude_plot', 'bode_phase_plot', 'bode_plot'] diff --git a/lib/python3.12/site-packages/sympy/physics/control/__pycache__/__init__.cpython-312.pyc b/lib/python3.12/site-packages/sympy/physics/control/__pycache__/__init__.cpython-312.pyc new file mode 100644 index 0000000000000000000000000000000000000000..a0c794b96ae18fb2cc619c096fb5ecd6ed9bc783 Binary files /dev/null and b/lib/python3.12/site-packages/sympy/physics/control/__pycache__/__init__.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/control/__pycache__/control_plots.cpython-312.pyc b/lib/python3.12/site-packages/sympy/physics/control/__pycache__/control_plots.cpython-312.pyc new file mode 100644 index 0000000000000000000000000000000000000000..6ae62faf2068cf2eaeaecd08001fcfc97642e116 Binary files /dev/null and b/lib/python3.12/site-packages/sympy/physics/control/__pycache__/control_plots.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/control/control_plots.py b/lib/python3.12/site-packages/sympy/physics/control/control_plots.py new file mode 100644 index 0000000000000000000000000000000000000000..3742de329e61a84ff604accaced369261bc4befe --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/control/control_plots.py @@ -0,0 +1,978 @@ +from sympy.core.numbers import I, pi +from sympy.functions.elementary.exponential import (exp, log) +from sympy.polys.partfrac import apart +from sympy.core.symbol import Dummy +from sympy.external import import_module +from sympy.functions import arg, Abs +from sympy.integrals.laplace import _fast_inverse_laplace +from sympy.physics.control.lti import SISOLinearTimeInvariant +from sympy.plotting.series import LineOver1DRangeSeries +from sympy.polys.polytools import Poly +from sympy.printing.latex import latex + +__all__ = ['pole_zero_numerical_data', 'pole_zero_plot', + 'step_response_numerical_data', 'step_response_plot', + 'impulse_response_numerical_data', 'impulse_response_plot', + 'ramp_response_numerical_data', 'ramp_response_plot', + 'bode_magnitude_numerical_data', 'bode_phase_numerical_data', + 'bode_magnitude_plot', 'bode_phase_plot', 'bode_plot'] + +matplotlib = import_module( + 'matplotlib', import_kwargs={'fromlist': ['pyplot']}, + catch=(RuntimeError,)) + +numpy = import_module('numpy') + +if matplotlib: + plt = matplotlib.pyplot + +if numpy: + np = numpy # Matplotlib already has numpy as a compulsory dependency. No need to install it separately. + + +def _check_system(system): + """Function to check whether the dynamical system passed for plots is + compatible or not.""" + if not isinstance(system, SISOLinearTimeInvariant): + raise NotImplementedError("Only SISO LTI systems are currently supported.") + sys = system.to_expr() + len_free_symbols = len(sys.free_symbols) + if len_free_symbols > 1: + raise ValueError("Extra degree of freedom found. Make sure" + " that there are no free symbols in the dynamical system other" + " than the variable of Laplace transform.") + if sys.has(exp): + # Should test that exp is not part of a constant, in which case + # no exception is required, compare exp(s) with s*exp(1) + raise NotImplementedError("Time delay terms are not supported.") + + +def pole_zero_numerical_data(system): + """ + Returns the numerical data of poles and zeros of the system. + It is internally used by ``pole_zero_plot`` to get the data + for plotting poles and zeros. Users can use this data to further + analyse the dynamics of the system or plot using a different + backend/plotting-module. + + Parameters + ========== + + system : SISOLinearTimeInvariant + The system for which the pole-zero data is to be computed. + + Returns + ======= + + tuple : (zeros, poles) + zeros = Zeros of the system. NumPy array of complex numbers. + poles = Poles of the system. NumPy array of complex numbers. + + Raises + ====== + + NotImplementedError + When a SISO LTI system is not passed. + + When time delay terms are present in the system. + + ValueError + When more than one free symbol is present in the system. + The only variable in the transfer function should be + the variable of the Laplace transform. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction + >>> from sympy.physics.control.control_plots import pole_zero_numerical_data + >>> tf1 = TransferFunction(s**2 + 1, s**4 + 4*s**3 + 6*s**2 + 5*s + 2, s) + >>> pole_zero_numerical_data(tf1) # doctest: +SKIP + ([-0.+1.j 0.-1.j], [-2. +0.j -0.5+0.8660254j -0.5-0.8660254j -1. +0.j ]) + + See Also + ======== + + pole_zero_plot + + """ + _check_system(system) + system = system.doit() # Get the equivalent TransferFunction object. + + num_poly = Poly(system.num, system.var).all_coeffs() + den_poly = Poly(system.den, system.var).all_coeffs() + + num_poly = np.array(num_poly, dtype=np.complex128) + den_poly = np.array(den_poly, dtype=np.complex128) + + zeros = np.roots(num_poly) + poles = np.roots(den_poly) + + return zeros, poles + + +def pole_zero_plot(system, pole_color='blue', pole_markersize=10, + zero_color='orange', zero_markersize=7, grid=True, show_axes=True, + show=True, **kwargs): + r""" + Returns the Pole-Zero plot (also known as PZ Plot or PZ Map) of a system. + + A Pole-Zero plot is a graphical representation of a system's poles and + zeros. It is plotted on a complex plane, with circular markers representing + the system's zeros and 'x' shaped markers representing the system's poles. + + Parameters + ========== + + system : SISOLinearTimeInvariant type systems + The system for which the pole-zero plot is to be computed. + pole_color : str, tuple, optional + The color of the pole points on the plot. Default color + is blue. The color can be provided as a matplotlib color string, + or a 3-tuple of floats each in the 0-1 range. + pole_markersize : Number, optional + The size of the markers used to mark the poles in the plot. + Default pole markersize is 10. + zero_color : str, tuple, optional + The color of the zero points on the plot. Default color + is orange. The color can be provided as a matplotlib color string, + or a 3-tuple of floats each in the 0-1 range. + zero_markersize : Number, optional + The size of the markers used to mark the zeros in the plot. + Default zero markersize is 7. + grid : boolean, optional + If ``True``, the plot will have a grid. Defaults to True. + show_axes : boolean, optional + If ``True``, the coordinate axes will be shown. Defaults to False. + show : boolean, optional + If ``True``, the plot will be displayed otherwise + the equivalent matplotlib ``plot`` object will be returned. + Defaults to True. + + Examples + ======== + + .. plot:: + :context: close-figs + :format: doctest + :include-source: True + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction + >>> from sympy.physics.control.control_plots import pole_zero_plot + >>> tf1 = TransferFunction(s**2 + 1, s**4 + 4*s**3 + 6*s**2 + 5*s + 2, s) + >>> pole_zero_plot(tf1) # doctest: +SKIP + + See Also + ======== + + pole_zero_numerical_data + + References + ========== + + .. [1] https://en.wikipedia.org/wiki/Pole%E2%80%93zero_plot + + """ + zeros, poles = pole_zero_numerical_data(system) + + zero_real = np.real(zeros) + zero_imag = np.imag(zeros) + + pole_real = np.real(poles) + pole_imag = np.imag(poles) + + plt.plot(pole_real, pole_imag, 'x', mfc='none', + markersize=pole_markersize, color=pole_color) + plt.plot(zero_real, zero_imag, 'o', markersize=zero_markersize, + color=zero_color) + plt.xlabel('Real Axis') + plt.ylabel('Imaginary Axis') + plt.title(f'Poles and Zeros of ${latex(system)}$', pad=20) + + if grid: + plt.grid() + if show_axes: + plt.axhline(0, color='black') + plt.axvline(0, color='black') + if show: + plt.show() + return + + return plt + + +def step_response_numerical_data(system, prec=8, lower_limit=0, + upper_limit=10, **kwargs): + """ + Returns the numerical values of the points in the step response plot + of a SISO continuous-time system. By default, adaptive sampling + is used. If the user wants to instead get an uniformly + sampled response, then ``adaptive`` kwarg should be passed ``False`` + and ``n`` must be passed as additional kwargs. + Refer to the parameters of class :class:`sympy.plotting.series.LineOver1DRangeSeries` + for more details. + + Parameters + ========== + + system : SISOLinearTimeInvariant + The system for which the unit step response data is to be computed. + prec : int, optional + The decimal point precision for the point coordinate values. + Defaults to 8. + lower_limit : Number, optional + The lower limit of the plot range. Defaults to 0. + upper_limit : Number, optional + The upper limit of the plot range. Defaults to 10. + kwargs : + Additional keyword arguments are passed to the underlying + :class:`sympy.plotting.series.LineOver1DRangeSeries` class. + + Returns + ======= + + tuple : (x, y) + x = Time-axis values of the points in the step response. NumPy array. + y = Amplitude-axis values of the points in the step response. NumPy array. + + Raises + ====== + + NotImplementedError + When a SISO LTI system is not passed. + + When time delay terms are present in the system. + + ValueError + When more than one free symbol is present in the system. + The only variable in the transfer function should be + the variable of the Laplace transform. + + When ``lower_limit`` parameter is less than 0. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction + >>> from sympy.physics.control.control_plots import step_response_numerical_data + >>> tf1 = TransferFunction(s, s**2 + 5*s + 8, s) + >>> step_response_numerical_data(tf1) # doctest: +SKIP + ([0.0, 0.025413462339411542, 0.0484508722725343, ... , 9.670250533855183, 9.844291913708725, 10.0], + [0.0, 0.023844582399907256, 0.042894276802320226, ..., 6.828770759094287e-12, 6.456457160755703e-12]) + + See Also + ======== + + step_response_plot + + """ + if lower_limit < 0: + raise ValueError("Lower limit of time must be greater " + "than or equal to zero.") + _check_system(system) + _x = Dummy("x") + expr = system.to_expr()/(system.var) + expr = apart(expr, system.var, full=True) + _y = _fast_inverse_laplace(expr, system.var, _x).evalf(prec) + return LineOver1DRangeSeries(_y, (_x, lower_limit, upper_limit), + **kwargs).get_points() + + +def step_response_plot(system, color='b', prec=8, lower_limit=0, + upper_limit=10, show_axes=False, grid=True, show=True, **kwargs): + r""" + Returns the unit step response of a continuous-time system. It is + the response of the system when the input signal is a step function. + + Parameters + ========== + + system : SISOLinearTimeInvariant type + The LTI SISO system for which the Step Response is to be computed. + color : str, tuple, optional + The color of the line. Default is Blue. + show : boolean, optional + If ``True``, the plot will be displayed otherwise + the equivalent matplotlib ``plot`` object will be returned. + Defaults to True. + lower_limit : Number, optional + The lower limit of the plot range. Defaults to 0. + upper_limit : Number, optional + The upper limit of the plot range. Defaults to 10. + prec : int, optional + The decimal point precision for the point coordinate values. + Defaults to 8. + show_axes : boolean, optional + If ``True``, the coordinate axes will be shown. Defaults to False. + grid : boolean, optional + If ``True``, the plot will have a grid. Defaults to True. + + Examples + ======== + + .. plot:: + :context: close-figs + :format: doctest + :include-source: True + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction + >>> from sympy.physics.control.control_plots import step_response_plot + >>> tf1 = TransferFunction(8*s**2 + 18*s + 32, s**3 + 6*s**2 + 14*s + 24, s) + >>> step_response_plot(tf1) # doctest: +SKIP + + See Also + ======== + + impulse_response_plot, ramp_response_plot + + References + ========== + + .. [1] https://www.mathworks.com/help/control/ref/lti.step.html + + """ + x, y = step_response_numerical_data(system, prec=prec, + lower_limit=lower_limit, upper_limit=upper_limit, **kwargs) + plt.plot(x, y, color=color) + plt.xlabel('Time (s)') + plt.ylabel('Amplitude') + plt.title(f'Unit Step Response of ${latex(system)}$', pad=20) + + if grid: + plt.grid() + if show_axes: + plt.axhline(0, color='black') + plt.axvline(0, color='black') + if show: + plt.show() + return + + return plt + + +def impulse_response_numerical_data(system, prec=8, lower_limit=0, + upper_limit=10, **kwargs): + """ + Returns the numerical values of the points in the impulse response plot + of a SISO continuous-time system. By default, adaptive sampling + is used. If the user wants to instead get an uniformly + sampled response, then ``adaptive`` kwarg should be passed ``False`` + and ``n`` must be passed as additional kwargs. + Refer to the parameters of class :class:`sympy.plotting.series.LineOver1DRangeSeries` + for more details. + + Parameters + ========== + + system : SISOLinearTimeInvariant + The system for which the impulse response data is to be computed. + prec : int, optional + The decimal point precision for the point coordinate values. + Defaults to 8. + lower_limit : Number, optional + The lower limit of the plot range. Defaults to 0. + upper_limit : Number, optional + The upper limit of the plot range. Defaults to 10. + kwargs : + Additional keyword arguments are passed to the underlying + :class:`sympy.plotting.series.LineOver1DRangeSeries` class. + + Returns + ======= + + tuple : (x, y) + x = Time-axis values of the points in the impulse response. NumPy array. + y = Amplitude-axis values of the points in the impulse response. NumPy array. + + Raises + ====== + + NotImplementedError + When a SISO LTI system is not passed. + + When time delay terms are present in the system. + + ValueError + When more than one free symbol is present in the system. + The only variable in the transfer function should be + the variable of the Laplace transform. + + When ``lower_limit`` parameter is less than 0. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction + >>> from sympy.physics.control.control_plots import impulse_response_numerical_data + >>> tf1 = TransferFunction(s, s**2 + 5*s + 8, s) + >>> impulse_response_numerical_data(tf1) # doctest: +SKIP + ([0.0, 0.06616480200395854,... , 9.854500743565858, 10.0], + [0.9999999799999999, 0.7042848373025861,...,7.170748906965121e-13, -5.1901263495547205e-12]) + + See Also + ======== + + impulse_response_plot + + """ + if lower_limit < 0: + raise ValueError("Lower limit of time must be greater " + "than or equal to zero.") + _check_system(system) + _x = Dummy("x") + expr = system.to_expr() + expr = apart(expr, system.var, full=True) + _y = _fast_inverse_laplace(expr, system.var, _x).evalf(prec) + return LineOver1DRangeSeries(_y, (_x, lower_limit, upper_limit), + **kwargs).get_points() + + +def impulse_response_plot(system, color='b', prec=8, lower_limit=0, + upper_limit=10, show_axes=False, grid=True, show=True, **kwargs): + r""" + Returns the unit impulse response (Input is the Dirac-Delta Function) of a + continuous-time system. + + Parameters + ========== + + system : SISOLinearTimeInvariant type + The LTI SISO system for which the Impulse Response is to be computed. + color : str, tuple, optional + The color of the line. Default is Blue. + show : boolean, optional + If ``True``, the plot will be displayed otherwise + the equivalent matplotlib ``plot`` object will be returned. + Defaults to True. + lower_limit : Number, optional + The lower limit of the plot range. Defaults to 0. + upper_limit : Number, optional + The upper limit of the plot range. Defaults to 10. + prec : int, optional + The decimal point precision for the point coordinate values. + Defaults to 8. + show_axes : boolean, optional + If ``True``, the coordinate axes will be shown. Defaults to False. + grid : boolean, optional + If ``True``, the plot will have a grid. Defaults to True. + + Examples + ======== + + .. plot:: + :context: close-figs + :format: doctest + :include-source: True + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction + >>> from sympy.physics.control.control_plots import impulse_response_plot + >>> tf1 = TransferFunction(8*s**2 + 18*s + 32, s**3 + 6*s**2 + 14*s + 24, s) + >>> impulse_response_plot(tf1) # doctest: +SKIP + + See Also + ======== + + step_response_plot, ramp_response_plot + + References + ========== + + .. [1] https://www.mathworks.com/help/control/ref/dynamicsystem.impulse.html + + """ + x, y = impulse_response_numerical_data(system, prec=prec, + lower_limit=lower_limit, upper_limit=upper_limit, **kwargs) + plt.plot(x, y, color=color) + plt.xlabel('Time (s)') + plt.ylabel('Amplitude') + plt.title(f'Impulse Response of ${latex(system)}$', pad=20) + + if grid: + plt.grid() + if show_axes: + plt.axhline(0, color='black') + plt.axvline(0, color='black') + if show: + plt.show() + return + + return plt + + +def ramp_response_numerical_data(system, slope=1, prec=8, + lower_limit=0, upper_limit=10, **kwargs): + """ + Returns the numerical values of the points in the ramp response plot + of a SISO continuous-time system. By default, adaptive sampling + is used. If the user wants to instead get an uniformly + sampled response, then ``adaptive`` kwarg should be passed ``False`` + and ``n`` must be passed as additional kwargs. + Refer to the parameters of class :class:`sympy.plotting.series.LineOver1DRangeSeries` + for more details. + + Parameters + ========== + + system : SISOLinearTimeInvariant + The system for which the ramp response data is to be computed. + slope : Number, optional + The slope of the input ramp function. Defaults to 1. + prec : int, optional + The decimal point precision for the point coordinate values. + Defaults to 8. + lower_limit : Number, optional + The lower limit of the plot range. Defaults to 0. + upper_limit : Number, optional + The upper limit of the plot range. Defaults to 10. + kwargs : + Additional keyword arguments are passed to the underlying + :class:`sympy.plotting.series.LineOver1DRangeSeries` class. + + Returns + ======= + + tuple : (x, y) + x = Time-axis values of the points in the ramp response plot. NumPy array. + y = Amplitude-axis values of the points in the ramp response plot. NumPy array. + + Raises + ====== + + NotImplementedError + When a SISO LTI system is not passed. + + When time delay terms are present in the system. + + ValueError + When more than one free symbol is present in the system. + The only variable in the transfer function should be + the variable of the Laplace transform. + + When ``lower_limit`` parameter is less than 0. + + When ``slope`` is negative. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction + >>> from sympy.physics.control.control_plots import ramp_response_numerical_data + >>> tf1 = TransferFunction(s, s**2 + 5*s + 8, s) + >>> ramp_response_numerical_data(tf1) # doctest: +SKIP + (([0.0, 0.12166980856813935,..., 9.861246379582118, 10.0], + [1.4504508011325967e-09, 0.006046440489058766,..., 0.12499999999568202, 0.12499999999661349])) + + See Also + ======== + + ramp_response_plot + + """ + if slope < 0: + raise ValueError("Slope must be greater than or equal" + " to zero.") + if lower_limit < 0: + raise ValueError("Lower limit of time must be greater " + "than or equal to zero.") + _check_system(system) + _x = Dummy("x") + expr = (slope*system.to_expr())/((system.var)**2) + expr = apart(expr, system.var, full=True) + _y = _fast_inverse_laplace(expr, system.var, _x).evalf(prec) + return LineOver1DRangeSeries(_y, (_x, lower_limit, upper_limit), + **kwargs).get_points() + + +def ramp_response_plot(system, slope=1, color='b', prec=8, lower_limit=0, + upper_limit=10, show_axes=False, grid=True, show=True, **kwargs): + r""" + Returns the ramp response of a continuous-time system. + + Ramp function is defined as the straight line + passing through origin ($f(x) = mx$). The slope of + the ramp function can be varied by the user and + the default value is 1. + + Parameters + ========== + + system : SISOLinearTimeInvariant type + The LTI SISO system for which the Ramp Response is to be computed. + slope : Number, optional + The slope of the input ramp function. Defaults to 1. + color : str, tuple, optional + The color of the line. Default is Blue. + show : boolean, optional + If ``True``, the plot will be displayed otherwise + the equivalent matplotlib ``plot`` object will be returned. + Defaults to True. + lower_limit : Number, optional + The lower limit of the plot range. Defaults to 0. + upper_limit : Number, optional + The upper limit of the plot range. Defaults to 10. + prec : int, optional + The decimal point precision for the point coordinate values. + Defaults to 8. + show_axes : boolean, optional + If ``True``, the coordinate axes will be shown. Defaults to False. + grid : boolean, optional + If ``True``, the plot will have a grid. Defaults to True. + + Examples + ======== + + .. plot:: + :context: close-figs + :format: doctest + :include-source: True + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction + >>> from sympy.physics.control.control_plots import ramp_response_plot + >>> tf1 = TransferFunction(s, (s+4)*(s+8), s) + >>> ramp_response_plot(tf1, upper_limit=2) # doctest: +SKIP + + See Also + ======== + + step_response_plot, impulse_response_plot + + References + ========== + + .. [1] https://en.wikipedia.org/wiki/Ramp_function + + """ + x, y = ramp_response_numerical_data(system, slope=slope, prec=prec, + lower_limit=lower_limit, upper_limit=upper_limit, **kwargs) + plt.plot(x, y, color=color) + plt.xlabel('Time (s)') + plt.ylabel('Amplitude') + plt.title(f'Ramp Response of ${latex(system)}$ [Slope = {slope}]', pad=20) + + if grid: + plt.grid() + if show_axes: + plt.axhline(0, color='black') + plt.axvline(0, color='black') + if show: + plt.show() + return + + return plt + + +def bode_magnitude_numerical_data(system, initial_exp=-5, final_exp=5, freq_unit='rad/sec', **kwargs): + """ + Returns the numerical data of the Bode magnitude plot of the system. + It is internally used by ``bode_magnitude_plot`` to get the data + for plotting Bode magnitude plot. Users can use this data to further + analyse the dynamics of the system or plot using a different + backend/plotting-module. + + Parameters + ========== + + system : SISOLinearTimeInvariant + The system for which the data is to be computed. + initial_exp : Number, optional + The initial exponent of 10 of the semilog plot. Defaults to -5. + final_exp : Number, optional + The final exponent of 10 of the semilog plot. Defaults to 5. + freq_unit : string, optional + User can choose between ``'rad/sec'`` (radians/second) and ``'Hz'`` (Hertz) as frequency units. + + Returns + ======= + + tuple : (x, y) + x = x-axis values of the Bode magnitude plot. + y = y-axis values of the Bode magnitude plot. + + Raises + ====== + + NotImplementedError + When a SISO LTI system is not passed. + + When time delay terms are present in the system. + + ValueError + When more than one free symbol is present in the system. + The only variable in the transfer function should be + the variable of the Laplace transform. + + When incorrect frequency units are given as input. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction + >>> from sympy.physics.control.control_plots import bode_magnitude_numerical_data + >>> tf1 = TransferFunction(s**2 + 1, s**4 + 4*s**3 + 6*s**2 + 5*s + 2, s) + >>> bode_magnitude_numerical_data(tf1) # doctest: +SKIP + ([1e-05, 1.5148378120533502e-05,..., 68437.36188804005, 100000.0], + [-6.020599914256786, -6.0205999155219505,..., -193.4117304087953, -200.00000000260573]) + + See Also + ======== + + bode_magnitude_plot, bode_phase_numerical_data + + """ + _check_system(system) + expr = system.to_expr() + freq_units = ('rad/sec', 'Hz') + if freq_unit not in freq_units: + raise ValueError('Only "rad/sec" and "Hz" are accepted frequency units.') + + _w = Dummy("w", real=True) + if freq_unit == 'Hz': + repl = I*_w*2*pi + else: + repl = I*_w + w_expr = expr.subs({system.var: repl}) + + mag = 20*log(Abs(w_expr), 10) + + x, y = LineOver1DRangeSeries(mag, + (_w, 10**initial_exp, 10**final_exp), xscale='log', **kwargs).get_points() + + return x, y + + +def bode_magnitude_plot(system, initial_exp=-5, final_exp=5, + color='b', show_axes=False, grid=True, show=True, freq_unit='rad/sec', **kwargs): + r""" + Returns the Bode magnitude plot of a continuous-time system. + + See ``bode_plot`` for all the parameters. + """ + x, y = bode_magnitude_numerical_data(system, initial_exp=initial_exp, + final_exp=final_exp, freq_unit=freq_unit) + plt.plot(x, y, color=color, **kwargs) + plt.xscale('log') + + + plt.xlabel('Frequency (%s) [Log Scale]' % freq_unit) + plt.ylabel('Magnitude (dB)') + plt.title(f'Bode Plot (Magnitude) of ${latex(system)}$', pad=20) + + if grid: + plt.grid(True) + if show_axes: + plt.axhline(0, color='black') + plt.axvline(0, color='black') + if show: + plt.show() + return + + return plt + + +def bode_phase_numerical_data(system, initial_exp=-5, final_exp=5, freq_unit='rad/sec', phase_unit='rad', phase_unwrap = True, **kwargs): + """ + Returns the numerical data of the Bode phase plot of the system. + It is internally used by ``bode_phase_plot`` to get the data + for plotting Bode phase plot. Users can use this data to further + analyse the dynamics of the system or plot using a different + backend/plotting-module. + + Parameters + ========== + + system : SISOLinearTimeInvariant + The system for which the Bode phase plot data is to be computed. + initial_exp : Number, optional + The initial exponent of 10 of the semilog plot. Defaults to -5. + final_exp : Number, optional + The final exponent of 10 of the semilog plot. Defaults to 5. + freq_unit : string, optional + User can choose between ``'rad/sec'`` (radians/second) and '``'Hz'`` (Hertz) as frequency units. + phase_unit : string, optional + User can choose between ``'rad'`` (radians) and ``'deg'`` (degree) as phase units. + phase_unwrap : bool, optional + Set to ``True`` by default. + + Returns + ======= + + tuple : (x, y) + x = x-axis values of the Bode phase plot. + y = y-axis values of the Bode phase plot. + + Raises + ====== + + NotImplementedError + When a SISO LTI system is not passed. + + When time delay terms are present in the system. + + ValueError + When more than one free symbol is present in the system. + The only variable in the transfer function should be + the variable of the Laplace transform. + + When incorrect frequency or phase units are given as input. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction + >>> from sympy.physics.control.control_plots import bode_phase_numerical_data + >>> tf1 = TransferFunction(s**2 + 1, s**4 + 4*s**3 + 6*s**2 + 5*s + 2, s) + >>> bode_phase_numerical_data(tf1) # doctest: +SKIP + ([1e-05, 1.4472354033813751e-05, 2.035581932165858e-05,..., 47577.3248186011, 67884.09326036123, 100000.0], + [-2.5000000000291665e-05, -3.6180885085e-05, -5.08895483066e-05,...,-3.1415085799262523, -3.14155265358979]) + + See Also + ======== + + bode_magnitude_plot, bode_phase_numerical_data + + """ + _check_system(system) + expr = system.to_expr() + freq_units = ('rad/sec', 'Hz') + phase_units = ('rad', 'deg') + if freq_unit not in freq_units: + raise ValueError('Only "rad/sec" and "Hz" are accepted frequency units.') + if phase_unit not in phase_units: + raise ValueError('Only "rad" and "deg" are accepted phase units.') + + _w = Dummy("w", real=True) + if freq_unit == 'Hz': + repl = I*_w*2*pi + else: + repl = I*_w + w_expr = expr.subs({system.var: repl}) + + if phase_unit == 'deg': + phase = arg(w_expr)*180/pi + else: + phase = arg(w_expr) + + x, y = LineOver1DRangeSeries(phase, + (_w, 10**initial_exp, 10**final_exp), xscale='log', **kwargs).get_points() + + half = None + if phase_unwrap: + if(phase_unit == 'rad'): + half = pi + elif(phase_unit == 'deg'): + half = 180 + if half: + unit = 2*half + for i in range(1, len(y)): + diff = y[i] - y[i - 1] + if diff > half: # Jump from -half to half + y[i] = (y[i] - unit) + elif diff < -half: # Jump from half to -half + y[i] = (y[i] + unit) + + return x, y + + +def bode_phase_plot(system, initial_exp=-5, final_exp=5, + color='b', show_axes=False, grid=True, show=True, freq_unit='rad/sec', phase_unit='rad', phase_unwrap=True, **kwargs): + r""" + Returns the Bode phase plot of a continuous-time system. + + See ``bode_plot`` for all the parameters. + """ + x, y = bode_phase_numerical_data(system, initial_exp=initial_exp, + final_exp=final_exp, freq_unit=freq_unit, phase_unit=phase_unit, phase_unwrap=phase_unwrap) + plt.plot(x, y, color=color, **kwargs) + plt.xscale('log') + + plt.xlabel('Frequency (%s) [Log Scale]' % freq_unit) + plt.ylabel('Phase (%s)' % phase_unit) + plt.title(f'Bode Plot (Phase) of ${latex(system)}$', pad=20) + + if grid: + plt.grid(True) + if show_axes: + plt.axhline(0, color='black') + plt.axvline(0, color='black') + if show: + plt.show() + return + + return plt + + +def bode_plot(system, initial_exp=-5, final_exp=5, + grid=True, show_axes=False, show=True, freq_unit='rad/sec', phase_unit='rad', phase_unwrap=True, **kwargs): + r""" + Returns the Bode phase and magnitude plots of a continuous-time system. + + Parameters + ========== + + system : SISOLinearTimeInvariant type + The LTI SISO system for which the Bode Plot is to be computed. + initial_exp : Number, optional + The initial exponent of 10 of the semilog plot. Defaults to -5. + final_exp : Number, optional + The final exponent of 10 of the semilog plot. Defaults to 5. + show : boolean, optional + If ``True``, the plot will be displayed otherwise + the equivalent matplotlib ``plot`` object will be returned. + Defaults to True. + prec : int, optional + The decimal point precision for the point coordinate values. + Defaults to 8. + grid : boolean, optional + If ``True``, the plot will have a grid. Defaults to True. + show_axes : boolean, optional + If ``True``, the coordinate axes will be shown. Defaults to False. + freq_unit : string, optional + User can choose between ``'rad/sec'`` (radians/second) and ``'Hz'`` (Hertz) as frequency units. + phase_unit : string, optional + User can choose between ``'rad'`` (radians) and ``'deg'`` (degree) as phase units. + + Examples + ======== + + .. plot:: + :context: close-figs + :format: doctest + :include-source: True + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction + >>> from sympy.physics.control.control_plots import bode_plot + >>> tf1 = TransferFunction(1*s**2 + 0.1*s + 7.5, 1*s**4 + 0.12*s**3 + 9*s**2, s) + >>> bode_plot(tf1, initial_exp=0.2, final_exp=0.7) # doctest: +SKIP + + See Also + ======== + + bode_magnitude_plot, bode_phase_plot + + """ + plt.subplot(211) + mag = bode_magnitude_plot(system, initial_exp=initial_exp, final_exp=final_exp, + show=False, grid=grid, show_axes=show_axes, + freq_unit=freq_unit, **kwargs) + mag.title(f'Bode Plot of ${latex(system)}$', pad=20) + mag.xlabel(None) + plt.subplot(212) + bode_phase_plot(system, initial_exp=initial_exp, final_exp=final_exp, + show=False, grid=grid, show_axes=show_axes, freq_unit=freq_unit, phase_unit=phase_unit, phase_unwrap=phase_unwrap, **kwargs).title(None) + + if show: + plt.show() + return + + return plt diff --git a/lib/python3.12/site-packages/sympy/physics/control/lti.py b/lib/python3.12/site-packages/sympy/physics/control/lti.py new file mode 100644 index 0000000000000000000000000000000000000000..54349e50e087077435ed2fcdf01c2aed23f0edea --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/control/lti.py @@ -0,0 +1,4304 @@ +from typing import Type +from sympy import Interval, numer, Rational, solveset +from sympy.core.add import Add +from sympy.core.basic import Basic +from sympy.core.containers import Tuple +from sympy.core.evalf import EvalfMixin +from sympy.core.expr import Expr +from sympy.core.function import expand +from sympy.core.logic import fuzzy_and +from sympy.core.mul import Mul +from sympy.core.numbers import I, pi, oo +from sympy.core.power import Pow +from sympy.core.singleton import S +from sympy.core.symbol import Dummy, Symbol +from sympy.functions import Abs +from sympy.core.sympify import sympify, _sympify +from sympy.matrices import Matrix, ImmutableMatrix, ImmutableDenseMatrix, eye, ShapeError, zeros +from sympy.functions.elementary.exponential import (exp, log) +from sympy.matrices.expressions import MatMul, MatAdd +from sympy.polys import Poly, rootof +from sympy.polys.polyroots import roots +from sympy.polys.polytools import (cancel, degree) +from sympy.series import limit +from sympy.utilities.misc import filldedent + +from mpmath.libmp.libmpf import prec_to_dps + +__all__ = ['TransferFunction', 'Series', 'MIMOSeries', 'Parallel', 'MIMOParallel', + 'Feedback', 'MIMOFeedback', 'TransferFunctionMatrix', 'StateSpace', 'gbt', 'bilinear', 'forward_diff', 'backward_diff', + 'phase_margin', 'gain_margin'] + +def _roots(poly, var): + """ like roots, but works on higher-order polynomials. """ + r = roots(poly, var, multiple=True) + n = degree(poly) + if len(r) != n: + r = [rootof(poly, var, k) for k in range(n)] + return r + +def gbt(tf, sample_per, alpha): + r""" + Returns falling coefficients of H(z) from numerator and denominator. + + Explanation + =========== + + Where H(z) is the corresponding discretized transfer function, + discretized with the generalised bilinear transformation method. + H(z) is obtained from the continuous transfer function H(s) + by substituting $s(z) = \frac{z-1}{T(\alpha z + (1-\alpha))}$ into H(s), where T is the + sample period. + Coefficients are falling, i.e. $H(z) = \frac{az+b}{cz+d}$ is returned + as [a, b], [c, d]. + + Examples + ======== + + >>> from sympy.physics.control.lti import TransferFunction, gbt + >>> from sympy.abc import s, L, R, T + + >>> tf = TransferFunction(1, s*L + R, s) + >>> numZ, denZ = gbt(tf, T, 0.5) + >>> numZ + [T/(2*(L + R*T/2)), T/(2*(L + R*T/2))] + >>> denZ + [1, (-L + R*T/2)/(L + R*T/2)] + + >>> numZ, denZ = gbt(tf, T, 0) + >>> numZ + [T/L] + >>> denZ + [1, (-L + R*T)/L] + + >>> numZ, denZ = gbt(tf, T, 1) + >>> numZ + [T/(L + R*T), 0] + >>> denZ + [1, -L/(L + R*T)] + + >>> numZ, denZ = gbt(tf, T, 0.3) + >>> numZ + [3*T/(10*(L + 3*R*T/10)), 7*T/(10*(L + 3*R*T/10))] + >>> denZ + [1, (-L + 7*R*T/10)/(L + 3*R*T/10)] + + References + ========== + + .. [1] https://www.polyu.edu.hk/ama/profile/gfzhang/Research/ZCC09_IJC.pdf + """ + if not tf.is_SISO: + raise NotImplementedError("Not implemented for MIMO systems.") + + T = sample_per # and sample period T + s = tf.var + z = s # dummy discrete variable z + + np = tf.num.as_poly(s).all_coeffs() + dp = tf.den.as_poly(s).all_coeffs() + alpha = Rational(alpha).limit_denominator(1000) + + # The next line results from multiplying H(z) with z^N/z^N + N = max(len(np), len(dp)) - 1 + num = Add(*[ T**(N-i) * c * (z-1)**i * (alpha * z + 1 - alpha)**(N-i) for c, i in zip(np[::-1], range(len(np))) ]) + den = Add(*[ T**(N-i) * c * (z-1)**i * (alpha * z + 1 - alpha)**(N-i) for c, i in zip(dp[::-1], range(len(dp))) ]) + + num_coefs = num.as_poly(z).all_coeffs() + den_coefs = den.as_poly(z).all_coeffs() + + para = den_coefs[0] + num_coefs = [coef/para for coef in num_coefs] + den_coefs = [coef/para for coef in den_coefs] + + return num_coefs, den_coefs + +def bilinear(tf, sample_per): + r""" + Returns falling coefficients of H(z) from numerator and denominator. + + Explanation + =========== + + Where H(z) is the corresponding discretized transfer function, + discretized with the bilinear transform method. + H(z) is obtained from the continuous transfer function H(s) + by substituting $s(z) = \frac{2}{T}\frac{z-1}{z+1}$ into H(s), where T is the + sample period. + Coefficients are falling, i.e. $H(z) = \frac{az+b}{cz+d}$ is returned + as [a, b], [c, d]. + + Examples + ======== + + >>> from sympy.physics.control.lti import TransferFunction, bilinear + >>> from sympy.abc import s, L, R, T + + >>> tf = TransferFunction(1, s*L + R, s) + >>> numZ, denZ = bilinear(tf, T) + >>> numZ + [T/(2*(L + R*T/2)), T/(2*(L + R*T/2))] + >>> denZ + [1, (-L + R*T/2)/(L + R*T/2)] + """ + return gbt(tf, sample_per, S.Half) + +def forward_diff(tf, sample_per): + r""" + Returns falling coefficients of H(z) from numerator and denominator. + + Explanation + =========== + + Where H(z) is the corresponding discretized transfer function, + discretized with the forward difference transform method. + H(z) is obtained from the continuous transfer function H(s) + by substituting $s(z) = \frac{z-1}{T}$ into H(s), where T is the + sample period. + Coefficients are falling, i.e. $H(z) = \frac{az+b}{cz+d}$ is returned + as [a, b], [c, d]. + + Examples + ======== + + >>> from sympy.physics.control.lti import TransferFunction, forward_diff + >>> from sympy.abc import s, L, R, T + + >>> tf = TransferFunction(1, s*L + R, s) + >>> numZ, denZ = forward_diff(tf, T) + >>> numZ + [T/L] + >>> denZ + [1, (-L + R*T)/L] + """ + return gbt(tf, sample_per, S.Zero) + +def backward_diff(tf, sample_per): + r""" + Returns falling coefficients of H(z) from numerator and denominator. + + Explanation + =========== + + Where H(z) is the corresponding discretized transfer function, + discretized with the backward difference transform method. + H(z) is obtained from the continuous transfer function H(s) + by substituting $s(z) = \frac{z-1}{Tz}$ into H(s), where T is the + sample period. + Coefficients are falling, i.e. $H(z) = \frac{az+b}{cz+d}$ is returned + as [a, b], [c, d]. + + Examples + ======== + + >>> from sympy.physics.control.lti import TransferFunction, backward_diff + >>> from sympy.abc import s, L, R, T + + >>> tf = TransferFunction(1, s*L + R, s) + >>> numZ, denZ = backward_diff(tf, T) + >>> numZ + [T/(L + R*T), 0] + >>> denZ + [1, -L/(L + R*T)] + """ + return gbt(tf, sample_per, S.One) + +def phase_margin(system): + r""" + Returns the phase margin of a continuous time system. + Only applicable to Transfer Functions which can generate valid bode plots. + + Raises + ====== + + NotImplementedError + When time delay terms are present in the system. + + ValueError + When a SISO LTI system is not passed. + + When more than one free symbol is present in the system. + The only variable in the transfer function should be + the variable of the Laplace transform. + + Examples + ======== + + >>> from sympy.physics.control import TransferFunction, phase_margin + >>> from sympy.abc import s + + >>> tf = TransferFunction(1, s**3 + 2*s**2 + s, s) + >>> phase_margin(tf) + 180*(-pi + atan((-1 + (-2*18**(1/3)/(9 + sqrt(93))**(1/3) + 12**(1/3)*(9 + sqrt(93))**(1/3))**2/36)/(-12**(1/3)*(9 + sqrt(93))**(1/3)/3 + 2*18**(1/3)/(3*(9 + sqrt(93))**(1/3)))))/pi + 180 + >>> phase_margin(tf).n() + 21.3863897518751 + + >>> tf1 = TransferFunction(s**3, s**2 + 5*s, s) + >>> phase_margin(tf1) + -180 + 180*(atan(sqrt(2)*(-51/10 - sqrt(101)/10)*sqrt(1 + sqrt(101))/(2*(sqrt(101)/2 + 51/2))) + pi)/pi + >>> phase_margin(tf1).n() + -25.1783920627277 + + >>> tf2 = TransferFunction(1, s + 1, s) + >>> phase_margin(tf2) + -180 + + See Also + ======== + + gain_margin + + References + ========== + + .. [1] https://en.wikipedia.org/wiki/Phase_margin + + """ + from sympy.functions import arg + + if not isinstance(system, SISOLinearTimeInvariant): + raise ValueError("Margins are only applicable for SISO LTI systems.") + + _w = Dummy("w", real=True) + repl = I*_w + expr = system.to_expr() + len_free_symbols = len(expr.free_symbols) + if expr.has(exp): + raise NotImplementedError("Margins for systems with Time delay terms are not supported.") + elif len_free_symbols > 1: + raise ValueError("Extra degree of freedom found. Make sure" + " that there are no free symbols in the dynamical system other" + " than the variable of Laplace transform.") + + w_expr = expr.subs({system.var: repl}) + + mag = 20*log(Abs(w_expr), 10) + mag_sol = list(solveset(mag, _w, Interval(0, oo, left_open=True))) + + if (len(mag_sol) == 0): + pm = S(-180) + else: + wcp = mag_sol[0] + pm = ((arg(w_expr)*S(180)/pi).subs({_w:wcp}) + S(180)) % 360 + + if(pm >= 180): + pm = pm - 360 + + return pm + +def gain_margin(system): + r""" + Returns the gain margin of a continuous time system. + Only applicable to Transfer Functions which can generate valid bode plots. + + Raises + ====== + + NotImplementedError + When time delay terms are present in the system. + + ValueError + When a SISO LTI system is not passed. + + When more than one free symbol is present in the system. + The only variable in the transfer function should be + the variable of the Laplace transform. + + Examples + ======== + + >>> from sympy.physics.control import TransferFunction, gain_margin + >>> from sympy.abc import s + + >>> tf = TransferFunction(1, s**3 + 2*s**2 + s, s) + >>> gain_margin(tf) + 20*log(2)/log(10) + >>> gain_margin(tf).n() + 6.02059991327962 + + >>> tf1 = TransferFunction(s**3, s**2 + 5*s, s) + >>> gain_margin(tf1) + oo + + See Also + ======== + + phase_margin + + References + ========== + + https://en.wikipedia.org/wiki/Bode_plot + + """ + if not isinstance(system, SISOLinearTimeInvariant): + raise ValueError("Margins are only applicable for SISO LTI systems.") + + _w = Dummy("w", real=True) + repl = I*_w + expr = system.to_expr() + len_free_symbols = len(expr.free_symbols) + if expr.has(exp): + raise NotImplementedError("Margins for systems with Time delay terms are not supported.") + elif len_free_symbols > 1: + raise ValueError("Extra degree of freedom found. Make sure" + " that there are no free symbols in the dynamical system other" + " than the variable of Laplace transform.") + + w_expr = expr.subs({system.var: repl}) + + mag = 20*log(Abs(w_expr), 10) + phase = w_expr + phase_sol = list(solveset(numer(phase.as_real_imag()[1].cancel()),_w, Interval(0, oo, left_open = True))) + + if (len(phase_sol) == 0): + gm = oo + else: + wcg = phase_sol[0] + gm = -mag.subs({_w:wcg}) + + return gm + +class LinearTimeInvariant(Basic, EvalfMixin): + """A common class for all the Linear Time-Invariant Dynamical Systems.""" + + _clstype: Type + + # Users should not directly interact with this class. + def __new__(cls, *system, **kwargs): + if cls is LinearTimeInvariant: + raise NotImplementedError('The LTICommon class is not meant to be used directly.') + return super(LinearTimeInvariant, cls).__new__(cls, *system, **kwargs) + + @classmethod + def _check_args(cls, args): + if not args: + raise ValueError("At least 1 argument must be passed.") + if not all(isinstance(arg, cls._clstype) for arg in args): + raise TypeError(f"All arguments must be of type {cls._clstype}.") + var_set = {arg.var for arg in args} + if len(var_set) != 1: + raise ValueError(filldedent(f""" + All transfer functions should use the same complex variable + of the Laplace transform. {len(var_set)} different + values found.""")) + + @property + def is_SISO(self): + """Returns `True` if the passed LTI system is SISO else returns False.""" + return self._is_SISO + + +class SISOLinearTimeInvariant(LinearTimeInvariant): + """A common class for all the SISO Linear Time-Invariant Dynamical Systems.""" + # Users should not directly interact with this class. + _is_SISO = True + + +class MIMOLinearTimeInvariant(LinearTimeInvariant): + """A common class for all the MIMO Linear Time-Invariant Dynamical Systems.""" + # Users should not directly interact with this class. + _is_SISO = False + + +SISOLinearTimeInvariant._clstype = SISOLinearTimeInvariant +MIMOLinearTimeInvariant._clstype = MIMOLinearTimeInvariant + + +def _check_other_SISO(func): + def wrapper(*args, **kwargs): + if not isinstance(args[-1], SISOLinearTimeInvariant): + return NotImplemented + else: + return func(*args, **kwargs) + return wrapper + + +def _check_other_MIMO(func): + def wrapper(*args, **kwargs): + if not isinstance(args[-1], MIMOLinearTimeInvariant): + return NotImplemented + else: + return func(*args, **kwargs) + return wrapper + + +class TransferFunction(SISOLinearTimeInvariant): + r""" + A class for representing LTI (Linear, time-invariant) systems that can be strictly described + by ratio of polynomials in the Laplace transform complex variable. The arguments + are ``num``, ``den``, and ``var``, where ``num`` and ``den`` are numerator and + denominator polynomials of the ``TransferFunction`` respectively, and the third argument is + a complex variable of the Laplace transform used by these polynomials of the transfer function. + ``num`` and ``den`` can be either polynomials or numbers, whereas ``var`` + has to be a :py:class:`~.Symbol`. + + Explanation + =========== + + Generally, a dynamical system representing a physical model can be described in terms of Linear + Ordinary Differential Equations like - + + $\small{b_{m}y^{\left(m\right)}+b_{m-1}y^{\left(m-1\right)}+\dots+b_{1}y^{\left(1\right)}+b_{0}y= + a_{n}x^{\left(n\right)}+a_{n-1}x^{\left(n-1\right)}+\dots+a_{1}x^{\left(1\right)}+a_{0}x}$ + + Here, $x$ is the input signal and $y$ is the output signal and superscript on both is the order of derivative + (not exponent). Derivative is taken with respect to the independent variable, $t$. Also, generally $m$ is greater + than $n$. + + It is not feasible to analyse the properties of such systems in their native form therefore, we use + mathematical tools like Laplace transform to get a better perspective. Taking the Laplace transform + of both the sides in the equation (at zero initial conditions), we get - + + $\small{\mathcal{L}[b_{m}y^{\left(m\right)}+b_{m-1}y^{\left(m-1\right)}+\dots+b_{1}y^{\left(1\right)}+b_{0}y]= + \mathcal{L}[a_{n}x^{\left(n\right)}+a_{n-1}x^{\left(n-1\right)}+\dots+a_{1}x^{\left(1\right)}+a_{0}x]}$ + + Using the linearity property of Laplace transform and also considering zero initial conditions + (i.e. $\small{y(0^{-}) = 0}$, $\small{y'(0^{-}) = 0}$ and so on), the equation + above gets translated to - + + $\small{b_{m}\mathcal{L}[y^{\left(m\right)}]+\dots+b_{1}\mathcal{L}[y^{\left(1\right)}]+b_{0}\mathcal{L}[y]= + a_{n}\mathcal{L}[x^{\left(n\right)}]+\dots+a_{1}\mathcal{L}[x^{\left(1\right)}]+a_{0}\mathcal{L}[x]}$ + + Now, applying Derivative property of Laplace transform, + + $\small{b_{m}s^{m}\mathcal{L}[y]+\dots+b_{1}s\mathcal{L}[y]+b_{0}\mathcal{L}[y]= + a_{n}s^{n}\mathcal{L}[x]+\dots+a_{1}s\mathcal{L}[x]+a_{0}\mathcal{L}[x]}$ + + Here, the superscript on $s$ is **exponent**. Note that the zero initial conditions assumption, mentioned above, is very important + and cannot be ignored otherwise the dynamical system cannot be considered time-independent and the simplified equation above + cannot be reached. + + Collecting $\mathcal{L}[y]$ and $\mathcal{L}[x]$ terms from both the sides and taking the ratio + $\frac{ \mathcal{L}\left\{y\right\} }{ \mathcal{L}\left\{x\right\} }$, we get the typical rational form of transfer + function. + + The numerator of the transfer function is, therefore, the Laplace transform of the output signal + (The signals are represented as functions of time) and similarly, the denominator + of the transfer function is the Laplace transform of the input signal. It is also a convention + to denote the input and output signal's Laplace transform with capital alphabets like shown below. + + $H(s) = \frac{Y(s)}{X(s)} = \frac{ \mathcal{L}\left\{y(t)\right\} }{ \mathcal{L}\left\{x(t)\right\} }$ + + $s$, also known as complex frequency, is a complex variable in the Laplace domain. It corresponds to the + equivalent variable $t$, in the time domain. Transfer functions are sometimes also referred to as the Laplace + transform of the system's impulse response. Transfer function, $H$, is represented as a rational + function in $s$ like, + + $H(s) =\ \frac{a_{n}s^{n}+a_{n-1}s^{n-1}+\dots+a_{1}s+a_{0}}{b_{m}s^{m}+b_{m-1}s^{m-1}+\dots+b_{1}s+b_{0}}$ + + Parameters + ========== + + num : Expr, Number + The numerator polynomial of the transfer function. + den : Expr, Number + The denominator polynomial of the transfer function. + var : Symbol + Complex variable of the Laplace transform used by the + polynomials of the transfer function. + + Raises + ====== + + TypeError + When ``var`` is not a Symbol or when ``num`` or ``den`` is not a + number or a polynomial. + ValueError + When ``den`` is zero. + + Examples + ======== + + >>> from sympy.abc import s, p, a + >>> from sympy.physics.control.lti import TransferFunction + >>> tf1 = TransferFunction(s + a, s**2 + s + 1, s) + >>> tf1 + TransferFunction(a + s, s**2 + s + 1, s) + >>> tf1.num + a + s + >>> tf1.den + s**2 + s + 1 + >>> tf1.var + s + >>> tf1.args + (a + s, s**2 + s + 1, s) + + Any complex variable can be used for ``var``. + + >>> tf2 = TransferFunction(a*p**3 - a*p**2 + s*p, p + a**2, p) + >>> tf2 + TransferFunction(a*p**3 - a*p**2 + p*s, a**2 + p, p) + >>> tf3 = TransferFunction((p + 3)*(p - 1), (p - 1)*(p + 5), p) + >>> tf3 + TransferFunction((p - 1)*(p + 3), (p - 1)*(p + 5), p) + + To negate a transfer function the ``-`` operator can be prepended: + + >>> tf4 = TransferFunction(-a + s, p**2 + s, p) + >>> -tf4 + TransferFunction(a - s, p**2 + s, p) + >>> tf5 = TransferFunction(s**4 - 2*s**3 + 5*s + 4, s + 4, s) + >>> -tf5 + TransferFunction(-s**4 + 2*s**3 - 5*s - 4, s + 4, s) + + You can use a float or an integer (or other constants) as numerator and denominator: + + >>> tf6 = TransferFunction(1/2, 4, s) + >>> tf6.num + 0.500000000000000 + >>> tf6.den + 4 + >>> tf6.var + s + >>> tf6.args + (0.5, 4, s) + + You can take the integer power of a transfer function using the ``**`` operator: + + >>> tf7 = TransferFunction(s + a, s - a, s) + >>> tf7**3 + TransferFunction((a + s)**3, (-a + s)**3, s) + >>> tf7**0 + TransferFunction(1, 1, s) + >>> tf8 = TransferFunction(p + 4, p - 3, p) + >>> tf8**-1 + TransferFunction(p - 3, p + 4, p) + + Addition, subtraction, and multiplication of transfer functions can form + unevaluated ``Series`` or ``Parallel`` objects. + + >>> tf9 = TransferFunction(s + 1, s**2 + s + 1, s) + >>> tf10 = TransferFunction(s - p, s + 3, s) + >>> tf11 = TransferFunction(4*s**2 + 2*s - 4, s - 1, s) + >>> tf12 = TransferFunction(1 - s, s**2 + 4, s) + >>> tf9 + tf10 + Parallel(TransferFunction(s + 1, s**2 + s + 1, s), TransferFunction(-p + s, s + 3, s)) + >>> tf10 - tf11 + Parallel(TransferFunction(-p + s, s + 3, s), TransferFunction(-4*s**2 - 2*s + 4, s - 1, s)) + >>> tf9 * tf10 + Series(TransferFunction(s + 1, s**2 + s + 1, s), TransferFunction(-p + s, s + 3, s)) + >>> tf10 - (tf9 + tf12) + Parallel(TransferFunction(-p + s, s + 3, s), TransferFunction(-s - 1, s**2 + s + 1, s), TransferFunction(s - 1, s**2 + 4, s)) + >>> tf10 - (tf9 * tf12) + Parallel(TransferFunction(-p + s, s + 3, s), Series(TransferFunction(-1, 1, s), TransferFunction(s + 1, s**2 + s + 1, s), TransferFunction(1 - s, s**2 + 4, s))) + >>> tf11 * tf10 * tf9 + Series(TransferFunction(4*s**2 + 2*s - 4, s - 1, s), TransferFunction(-p + s, s + 3, s), TransferFunction(s + 1, s**2 + s + 1, s)) + >>> tf9 * tf11 + tf10 * tf12 + Parallel(Series(TransferFunction(s + 1, s**2 + s + 1, s), TransferFunction(4*s**2 + 2*s - 4, s - 1, s)), Series(TransferFunction(-p + s, s + 3, s), TransferFunction(1 - s, s**2 + 4, s))) + >>> (tf9 + tf12) * (tf10 + tf11) + Series(Parallel(TransferFunction(s + 1, s**2 + s + 1, s), TransferFunction(1 - s, s**2 + 4, s)), Parallel(TransferFunction(-p + s, s + 3, s), TransferFunction(4*s**2 + 2*s - 4, s - 1, s))) + + These unevaluated ``Series`` or ``Parallel`` objects can convert into the + resultant transfer function using ``.doit()`` method or by ``.rewrite(TransferFunction)``. + + >>> ((tf9 + tf10) * tf12).doit() + TransferFunction((1 - s)*((-p + s)*(s**2 + s + 1) + (s + 1)*(s + 3)), (s + 3)*(s**2 + 4)*(s**2 + s + 1), s) + >>> (tf9 * tf10 - tf11 * tf12).rewrite(TransferFunction) + TransferFunction(-(1 - s)*(s + 3)*(s**2 + s + 1)*(4*s**2 + 2*s - 4) + (-p + s)*(s - 1)*(s + 1)*(s**2 + 4), (s - 1)*(s + 3)*(s**2 + 4)*(s**2 + s + 1), s) + + See Also + ======== + + Feedback, Series, Parallel + + References + ========== + + .. [1] https://en.wikipedia.org/wiki/Transfer_function + .. [2] https://en.wikipedia.org/wiki/Laplace_transform + + """ + def __new__(cls, num, den, var): + num, den = _sympify(num), _sympify(den) + + if not isinstance(var, Symbol): + raise TypeError("Variable input must be a Symbol.") + + if den == 0: + raise ValueError("TransferFunction cannot have a zero denominator.") + + if (((isinstance(num, (Expr, TransferFunction, Series, Parallel)) and num.has(Symbol)) or num.is_number) and + ((isinstance(den, (Expr, TransferFunction, Series, Parallel)) and den.has(Symbol)) or den.is_number)): + return super(TransferFunction, cls).__new__(cls, num, den, var) + + else: + raise TypeError("Unsupported type for numerator or denominator of TransferFunction.") + + @classmethod + def from_rational_expression(cls, expr, var=None): + r""" + Creates a new ``TransferFunction`` efficiently from a rational expression. + + Parameters + ========== + + expr : Expr, Number + The rational expression representing the ``TransferFunction``. + var : Symbol, optional + Complex variable of the Laplace transform used by the + polynomials of the transfer function. + + Raises + ====== + + ValueError + When ``expr`` is of type ``Number`` and optional parameter ``var`` + is not passed. + + When ``expr`` has more than one variables and an optional parameter + ``var`` is not passed. + ZeroDivisionError + When denominator of ``expr`` is zero or it has ``ComplexInfinity`` + in its numerator. + + Examples + ======== + + >>> from sympy.abc import s, p, a + >>> from sympy.physics.control.lti import TransferFunction + >>> expr1 = (s + 5)/(3*s**2 + 2*s + 1) + >>> tf1 = TransferFunction.from_rational_expression(expr1) + >>> tf1 + TransferFunction(s + 5, 3*s**2 + 2*s + 1, s) + >>> expr2 = (a*p**3 - a*p**2 + s*p)/(p + a**2) # Expr with more than one variables + >>> tf2 = TransferFunction.from_rational_expression(expr2, p) + >>> tf2 + TransferFunction(a*p**3 - a*p**2 + p*s, a**2 + p, p) + + In case of conflict between two or more variables in a expression, SymPy will + raise a ``ValueError``, if ``var`` is not passed by the user. + + >>> tf = TransferFunction.from_rational_expression((a + a*s)/(s**2 + s + 1)) + Traceback (most recent call last): + ... + ValueError: Conflicting values found for positional argument `var` ({a, s}). Specify it manually. + + This can be corrected by specifying the ``var`` parameter manually. + + >>> tf = TransferFunction.from_rational_expression((a + a*s)/(s**2 + s + 1), s) + >>> tf + TransferFunction(a*s + a, s**2 + s + 1, s) + + ``var`` also need to be specified when ``expr`` is a ``Number`` + + >>> tf3 = TransferFunction.from_rational_expression(10, s) + >>> tf3 + TransferFunction(10, 1, s) + + """ + expr = _sympify(expr) + if var is None: + _free_symbols = expr.free_symbols + _len_free_symbols = len(_free_symbols) + if _len_free_symbols == 1: + var = list(_free_symbols)[0] + elif _len_free_symbols == 0: + raise ValueError(filldedent(""" + Positional argument `var` not found in the + TransferFunction defined. Specify it manually.""")) + else: + raise ValueError(filldedent(""" + Conflicting values found for positional argument `var` ({}). + Specify it manually.""".format(_free_symbols))) + + _num, _den = expr.as_numer_denom() + if _den == 0 or _num.has(S.ComplexInfinity): + raise ZeroDivisionError("TransferFunction cannot have a zero denominator.") + return cls(_num, _den, var) + + @classmethod + def from_coeff_lists(cls, num_list, den_list, var): + r""" + Creates a new ``TransferFunction`` efficiently from a list of coefficients. + + Parameters + ========== + + num_list : Sequence + Sequence comprising of numerator coefficients. + den_list : Sequence + Sequence comprising of denominator coefficients. + var : Symbol + Complex variable of the Laplace transform used by the + polynomials of the transfer function. + + Raises + ====== + + ZeroDivisionError + When the constructed denominator is zero. + + Examples + ======== + + >>> from sympy.abc import s, p + >>> from sympy.physics.control.lti import TransferFunction + >>> num = [1, 0, 2] + >>> den = [3, 2, 2, 1] + >>> tf = TransferFunction.from_coeff_lists(num, den, s) + >>> tf + TransferFunction(s**2 + 2, 3*s**3 + 2*s**2 + 2*s + 1, s) + + # Create a Transfer Function with more than one variable + >>> tf1 = TransferFunction.from_coeff_lists([p, 1], [2*p, 0, 4], s) + >>> tf1 + TransferFunction(p*s + 1, 2*p*s**2 + 4, s) + + """ + num_list = num_list[::-1] + den_list = den_list[::-1] + num_var_powers = [var**i for i in range(len(num_list))] + den_var_powers = [var**i for i in range(len(den_list))] + + _num = sum(coeff * var_power for coeff, var_power in zip(num_list, num_var_powers)) + _den = sum(coeff * var_power for coeff, var_power in zip(den_list, den_var_powers)) + + if _den == 0: + raise ZeroDivisionError("TransferFunction cannot have a zero denominator.") + + return cls(_num, _den, var) + + @classmethod + def from_zpk(cls, zeros, poles, gain, var): + r""" + Creates a new ``TransferFunction`` from given zeros, poles and gain. + + Parameters + ========== + + zeros : Sequence + Sequence comprising of zeros of transfer function. + poles : Sequence + Sequence comprising of poles of transfer function. + gain : Number, Symbol, Expression + A scalar value specifying gain of the model. + var : Symbol + Complex variable of the Laplace transform used by the + polynomials of the transfer function. + + Examples + ======== + + >>> from sympy.abc import s, p, k + >>> from sympy.physics.control.lti import TransferFunction + >>> zeros = [1, 2, 3] + >>> poles = [6, 5, 4] + >>> gain = 7 + >>> tf = TransferFunction.from_zpk(zeros, poles, gain, s) + >>> tf + TransferFunction(7*(s - 3)*(s - 2)*(s - 1), (s - 6)*(s - 5)*(s - 4), s) + + # Create a Transfer Function with variable poles and zeros + >>> tf1 = TransferFunction.from_zpk([p, k], [p + k, p - k], 2, s) + >>> tf1 + TransferFunction(2*(-k + s)*(-p + s), (-k - p + s)*(k - p + s), s) + + # Complex poles or zeros are acceptable + >>> tf2 = TransferFunction.from_zpk([0], [1-1j, 1+1j, 2], -2, s) + >>> tf2 + TransferFunction(-2*s, (s - 2)*(s - 1.0 - 1.0*I)*(s - 1.0 + 1.0*I), s) + + """ + num_poly = 1 + den_poly = 1 + for zero in zeros: + num_poly *= var - zero + for pole in poles: + den_poly *= var - pole + + return cls(gain*num_poly, den_poly, var) + + @property + def num(self): + """ + Returns the numerator polynomial of the transfer function. + + Examples + ======== + + >>> from sympy.abc import s, p + >>> from sympy.physics.control.lti import TransferFunction + >>> G1 = TransferFunction(s**2 + p*s + 3, s - 4, s) + >>> G1.num + p*s + s**2 + 3 + >>> G2 = TransferFunction((p + 5)*(p - 3), (p - 3)*(p + 1), p) + >>> G2.num + (p - 3)*(p + 5) + + """ + return self.args[0] + + @property + def den(self): + """ + Returns the denominator polynomial of the transfer function. + + Examples + ======== + + >>> from sympy.abc import s, p + >>> from sympy.physics.control.lti import TransferFunction + >>> G1 = TransferFunction(s + 4, p**3 - 2*p + 4, s) + >>> G1.den + p**3 - 2*p + 4 + >>> G2 = TransferFunction(3, 4, s) + >>> G2.den + 4 + + """ + return self.args[1] + + @property + def var(self): + """ + Returns the complex variable of the Laplace transform used by the polynomials of + the transfer function. + + Examples + ======== + + >>> from sympy.abc import s, p + >>> from sympy.physics.control.lti import TransferFunction + >>> G1 = TransferFunction(p**2 + 2*p + 4, p - 6, p) + >>> G1.var + p + >>> G2 = TransferFunction(0, s - 5, s) + >>> G2.var + s + + """ + return self.args[2] + + def _eval_subs(self, old, new): + arg_num = self.num.subs(old, new) + arg_den = self.den.subs(old, new) + argnew = TransferFunction(arg_num, arg_den, self.var) + return self if old == self.var else argnew + + def _eval_evalf(self, prec): + return TransferFunction( + self.num._eval_evalf(prec), + self.den._eval_evalf(prec), + self.var) + + def _eval_simplify(self, **kwargs): + tf = cancel(Mul(self.num, 1/self.den, evaluate=False), expand=False).as_numer_denom() + num_, den_ = tf[0], tf[1] + return TransferFunction(num_, den_, self.var) + + def _eval_rewrite_as_StateSpace(self, *args): + """ + Returns the equivalent space space model of the transfer function model. + The state space model will be returned in the controllable cannonical form. + + Unlike the space state to transfer function model conversion, the transfer function + to state space model conversion is not unique. There can be multiple state space + representations of a given transfer function model. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control import TransferFunction, StateSpace + >>> tf = TransferFunction(s**2 + 1, s**3 + 2*s + 10, s) + >>> tf.rewrite(StateSpace) + StateSpace(Matrix([ + [ 0, 1, 0], + [ 0, 0, 1], + [-10, -2, 0]]), Matrix([ + [0], + [0], + [1]]), Matrix([[1, 0, 1]]), Matrix([[0]])) + + """ + if not self.is_proper: + raise ValueError("Transfer Function must be proper.") + + num_poly = Poly(self.num, self.var) + den_poly = Poly(self.den, self.var) + n = den_poly.degree() + + num_coeffs = num_poly.all_coeffs() + den_coeffs = den_poly.all_coeffs() + diff = n - num_poly.degree() + num_coeffs = [0]*diff + num_coeffs + + a = den_coeffs[1:] + a_mat = Matrix([[(-1)*coefficient/den_coeffs[0] for coefficient in reversed(a)]]) + vert = zeros(n-1, 1) + mat = eye(n-1) + A = vert.row_join(mat) + A = A.col_join(a_mat) + + B = zeros(n, 1) + B[n-1] = 1 + + i = n + C = [] + while(i > 0): + C.append(num_coeffs[i] - den_coeffs[i]*num_coeffs[0]) + i -= 1 + C = Matrix([C]) + + D = Matrix([num_coeffs[0]]) + + return StateSpace(A, B, C, D) + + def expand(self): + """ + Returns the transfer function with numerator and denominator + in expanded form. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction + >>> G1 = TransferFunction((a - s)**2, (s**2 + a)**2, s) + >>> G1.expand() + TransferFunction(a**2 - 2*a*s + s**2, a**2 + 2*a*s**2 + s**4, s) + >>> G2 = TransferFunction((p + 3*b)*(p - b), (p - b)*(p + 2*b), p) + >>> G2.expand() + TransferFunction(-3*b**2 + 2*b*p + p**2, -2*b**2 + b*p + p**2, p) + + """ + return TransferFunction(expand(self.num), expand(self.den), self.var) + + def dc_gain(self): + """ + Computes the gain of the response as the frequency approaches zero. + + The DC gain is infinite for systems with pure integrators. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction + >>> tf1 = TransferFunction(s + 3, s**2 - 9, s) + >>> tf1.dc_gain() + -1/3 + >>> tf2 = TransferFunction(p**2, p - 3 + p**3, p) + >>> tf2.dc_gain() + 0 + >>> tf3 = TransferFunction(a*p**2 - b, s + b, s) + >>> tf3.dc_gain() + (a*p**2 - b)/b + >>> tf4 = TransferFunction(1, s, s) + >>> tf4.dc_gain() + oo + + """ + m = Mul(self.num, Pow(self.den, -1, evaluate=False), evaluate=False) + return limit(m, self.var, 0) + + def poles(self): + """ + Returns the poles of a transfer function. + + Examples + ======== + + >>> from sympy.abc import s, p, a + >>> from sympy.physics.control.lti import TransferFunction + >>> tf1 = TransferFunction((p + 3)*(p - 1), (p - 1)*(p + 5), p) + >>> tf1.poles() + [-5, 1] + >>> tf2 = TransferFunction((1 - s)**2, (s**2 + 1)**2, s) + >>> tf2.poles() + [I, I, -I, -I] + >>> tf3 = TransferFunction(s**2, a*s + p, s) + >>> tf3.poles() + [-p/a] + + """ + return _roots(Poly(self.den, self.var), self.var) + + def zeros(self): + """ + Returns the zeros of a transfer function. + + Examples + ======== + + >>> from sympy.abc import s, p, a + >>> from sympy.physics.control.lti import TransferFunction + >>> tf1 = TransferFunction((p + 3)*(p - 1), (p - 1)*(p + 5), p) + >>> tf1.zeros() + [-3, 1] + >>> tf2 = TransferFunction((1 - s)**2, (s**2 + 1)**2, s) + >>> tf2.zeros() + [1, 1] + >>> tf3 = TransferFunction(s**2, a*s + p, s) + >>> tf3.zeros() + [0, 0] + + """ + return _roots(Poly(self.num, self.var), self.var) + + def eval_frequency(self, other): + """ + Returns the system response at any point in the real or complex plane. + + Examples + ======== + + >>> from sympy.abc import s, p, a + >>> from sympy.physics.control.lti import TransferFunction + >>> from sympy import I + >>> tf1 = TransferFunction(1, s**2 + 2*s + 1, s) + >>> omega = 0.1 + >>> tf1.eval_frequency(I*omega) + 1/(0.99 + 0.2*I) + >>> tf2 = TransferFunction(s**2, a*s + p, s) + >>> tf2.eval_frequency(2) + 4/(2*a + p) + >>> tf2.eval_frequency(I*2) + -4/(2*I*a + p) + """ + arg_num = self.num.subs(self.var, other) + arg_den = self.den.subs(self.var, other) + argnew = TransferFunction(arg_num, arg_den, self.var).to_expr() + return argnew.expand() + + def is_stable(self): + """ + Returns True if the transfer function is asymptotically stable; else False. + + This would not check the marginal or conditional stability of the system. + + Examples + ======== + + >>> from sympy.abc import s, p, a + >>> from sympy import symbols + >>> from sympy.physics.control.lti import TransferFunction + >>> q, r = symbols('q, r', negative=True) + >>> tf1 = TransferFunction((1 - s)**2, (s + 1)**2, s) + >>> tf1.is_stable() + True + >>> tf2 = TransferFunction((1 - p)**2, (s**2 + 1)**2, s) + >>> tf2.is_stable() + False + >>> tf3 = TransferFunction(4, q*s - r, s) + >>> tf3.is_stable() + False + >>> tf4 = TransferFunction(p + 1, a*p - s**2, p) + >>> tf4.is_stable() is None # Not enough info about the symbols to determine stability + True + + """ + return fuzzy_and(pole.as_real_imag()[0].is_negative for pole in self.poles()) + + def __add__(self, other): + if isinstance(other, (TransferFunction, Series)): + if not self.var == other.var: + raise ValueError(filldedent(""" + All the transfer functions should use the same complex variable + of the Laplace transform.""")) + return Parallel(self, other) + elif isinstance(other, Parallel): + if not self.var == other.var: + raise ValueError(filldedent(""" + All the transfer functions should use the same complex variable + of the Laplace transform.""")) + arg_list = list(other.args) + return Parallel(self, *arg_list) + else: + raise ValueError("TransferFunction cannot be added with {}.". + format(type(other))) + + def __radd__(self, other): + return self + other + + def __sub__(self, other): + if isinstance(other, (TransferFunction, Series)): + if not self.var == other.var: + raise ValueError(filldedent(""" + All the transfer functions should use the same complex variable + of the Laplace transform.""")) + return Parallel(self, -other) + elif isinstance(other, Parallel): + if not self.var == other.var: + raise ValueError(filldedent(""" + All the transfer functions should use the same complex variable + of the Laplace transform.""")) + arg_list = [-i for i in list(other.args)] + return Parallel(self, *arg_list) + else: + raise ValueError("{} cannot be subtracted from a TransferFunction." + .format(type(other))) + + def __rsub__(self, other): + return -self + other + + def __mul__(self, other): + if isinstance(other, (TransferFunction, Parallel)): + if not self.var == other.var: + raise ValueError(filldedent(""" + All the transfer functions should use the same complex variable + of the Laplace transform.""")) + return Series(self, other) + elif isinstance(other, Series): + if not self.var == other.var: + raise ValueError(filldedent(""" + All the transfer functions should use the same complex variable + of the Laplace transform.""")) + arg_list = list(other.args) + return Series(self, *arg_list) + else: + raise ValueError("TransferFunction cannot be multiplied with {}." + .format(type(other))) + + __rmul__ = __mul__ + + def __truediv__(self, other): + if isinstance(other, TransferFunction): + if not self.var == other.var: + raise ValueError(filldedent(""" + All the transfer functions should use the same complex variable + of the Laplace transform.""")) + return Series(self, TransferFunction(other.den, other.num, self.var)) + elif (isinstance(other, Parallel) and len(other.args + ) == 2 and isinstance(other.args[0], TransferFunction) + and isinstance(other.args[1], (Series, TransferFunction))): + + if not self.var == other.var: + raise ValueError(filldedent(""" + Both TransferFunction and Parallel should use the + same complex variable of the Laplace transform.""")) + if other.args[1] == self: + # plant and controller with unit feedback. + return Feedback(self, other.args[0]) + other_arg_list = list(other.args[1].args) if isinstance( + other.args[1], Series) else other.args[1] + if other_arg_list == other.args[1]: + return Feedback(self, other_arg_list) + elif self in other_arg_list: + other_arg_list.remove(self) + else: + return Feedback(self, Series(*other_arg_list)) + + if len(other_arg_list) == 1: + return Feedback(self, *other_arg_list) + else: + return Feedback(self, Series(*other_arg_list)) + else: + raise ValueError("TransferFunction cannot be divided by {}.". + format(type(other))) + + __rtruediv__ = __truediv__ + + def __pow__(self, p): + p = sympify(p) + if not p.is_Integer: + raise ValueError("Exponent must be an integer.") + if p is S.Zero: + return TransferFunction(1, 1, self.var) + elif p > 0: + num_, den_ = self.num**p, self.den**p + else: + p = abs(p) + num_, den_ = self.den**p, self.num**p + + return TransferFunction(num_, den_, self.var) + + def __neg__(self): + return TransferFunction(-self.num, self.den, self.var) + + @property + def is_proper(self): + """ + Returns True if degree of the numerator polynomial is less than + or equal to degree of the denominator polynomial, else False. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction + >>> tf1 = TransferFunction(b*s**2 + p**2 - a*p + s, b - p**2, s) + >>> tf1.is_proper + False + >>> tf2 = TransferFunction(p**2 - 4*p, p**3 + 3*p + 2, p) + >>> tf2.is_proper + True + + """ + return degree(self.num, self.var) <= degree(self.den, self.var) + + @property + def is_strictly_proper(self): + """ + Returns True if degree of the numerator polynomial is strictly less + than degree of the denominator polynomial, else False. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction + >>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s) + >>> tf1.is_strictly_proper + False + >>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s) + >>> tf2.is_strictly_proper + True + + """ + return degree(self.num, self.var) < degree(self.den, self.var) + + @property + def is_biproper(self): + """ + Returns True if degree of the numerator polynomial is equal to + degree of the denominator polynomial, else False. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction + >>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s) + >>> tf1.is_biproper + True + >>> tf2 = TransferFunction(p**2, p + a, p) + >>> tf2.is_biproper + False + + """ + return degree(self.num, self.var) == degree(self.den, self.var) + + def to_expr(self): + """ + Converts a ``TransferFunction`` object to SymPy Expr. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction + >>> from sympy import Expr + >>> tf1 = TransferFunction(s, a*s**2 + 1, s) + >>> tf1.to_expr() + s/(a*s**2 + 1) + >>> isinstance(_, Expr) + True + >>> tf2 = TransferFunction(1, (p + 3*b)*(b - p), p) + >>> tf2.to_expr() + 1/((b - p)*(3*b + p)) + >>> tf3 = TransferFunction((s - 2)*(s - 3), (s - 1)*(s - 2)*(s - 3), s) + >>> tf3.to_expr() + ((s - 3)*(s - 2))/(((s - 3)*(s - 2)*(s - 1))) + + """ + + if self.num != 1: + return Mul(self.num, Pow(self.den, -1, evaluate=False), evaluate=False) + else: + return Pow(self.den, -1, evaluate=False) + + +def _flatten_args(args, _cls): + temp_args = [] + for arg in args: + if isinstance(arg, _cls): + temp_args.extend(arg.args) + else: + temp_args.append(arg) + return tuple(temp_args) + + +def _dummify_args(_arg, var): + dummy_dict = {} + dummy_arg_list = [] + + for arg in _arg: + _s = Dummy() + dummy_dict[_s] = var + dummy_arg = arg.subs({var: _s}) + dummy_arg_list.append(dummy_arg) + + return dummy_arg_list, dummy_dict + + +class Series(SISOLinearTimeInvariant): + r""" + A class for representing a series configuration of SISO systems. + + Parameters + ========== + + args : SISOLinearTimeInvariant + SISO systems in a series configuration. + evaluate : Boolean, Keyword + When passed ``True``, returns the equivalent + ``Series(*args).doit()``. Set to ``False`` by default. + + Raises + ====== + + ValueError + When no argument is passed. + + ``var`` attribute is not same for every system. + TypeError + Any of the passed ``*args`` has unsupported type + + A combination of SISO and MIMO systems is + passed. There should be homogeneity in the + type of systems passed, SISO in this case. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction, Series, Parallel + >>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s) + >>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s) + >>> tf3 = TransferFunction(p**2, p + s, s) + >>> S1 = Series(tf1, tf2) + >>> S1 + Series(TransferFunction(a*p**2 + b*s, -p + s, s), TransferFunction(s**3 - 2, s**4 + 5*s + 6, s)) + >>> S1.var + s + >>> S2 = Series(tf2, Parallel(tf3, -tf1)) + >>> S2 + Series(TransferFunction(s**3 - 2, s**4 + 5*s + 6, s), Parallel(TransferFunction(p**2, p + s, s), TransferFunction(-a*p**2 - b*s, -p + s, s))) + >>> S2.var + s + >>> S3 = Series(Parallel(tf1, tf2), Parallel(tf2, tf3)) + >>> S3 + Series(Parallel(TransferFunction(a*p**2 + b*s, -p + s, s), TransferFunction(s**3 - 2, s**4 + 5*s + 6, s)), Parallel(TransferFunction(s**3 - 2, s**4 + 5*s + 6, s), TransferFunction(p**2, p + s, s))) + >>> S3.var + s + + You can get the resultant transfer function by using ``.doit()`` method: + + >>> S3 = Series(tf1, tf2, -tf3) + >>> S3.doit() + TransferFunction(-p**2*(s**3 - 2)*(a*p**2 + b*s), (-p + s)*(p + s)*(s**4 + 5*s + 6), s) + >>> S4 = Series(tf2, Parallel(tf1, -tf3)) + >>> S4.doit() + TransferFunction((s**3 - 2)*(-p**2*(-p + s) + (p + s)*(a*p**2 + b*s)), (-p + s)*(p + s)*(s**4 + 5*s + 6), s) + + Notes + ===== + + All the transfer functions should use the same complex variable + ``var`` of the Laplace transform. + + See Also + ======== + + MIMOSeries, Parallel, TransferFunction, Feedback + + """ + def __new__(cls, *args, evaluate=False): + + args = _flatten_args(args, Series) + cls._check_args(args) + obj = super().__new__(cls, *args) + + return obj.doit() if evaluate else obj + + @property + def var(self): + """ + Returns the complex variable used by all the transfer functions. + + Examples + ======== + + >>> from sympy.abc import p + >>> from sympy.physics.control.lti import TransferFunction, Series, Parallel + >>> G1 = TransferFunction(p**2 + 2*p + 4, p - 6, p) + >>> G2 = TransferFunction(p, 4 - p, p) + >>> G3 = TransferFunction(0, p**4 - 1, p) + >>> Series(G1, G2).var + p + >>> Series(-G3, Parallel(G1, G2)).var + p + + """ + return self.args[0].var + + def doit(self, **hints): + """ + Returns the resultant transfer function obtained after evaluating + the transfer functions in series configuration. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction, Series + >>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s) + >>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s) + >>> Series(tf2, tf1).doit() + TransferFunction((s**3 - 2)*(a*p**2 + b*s), (-p + s)*(s**4 + 5*s + 6), s) + >>> Series(-tf1, -tf2).doit() + TransferFunction((2 - s**3)*(-a*p**2 - b*s), (-p + s)*(s**4 + 5*s + 6), s) + + """ + + _num_arg = (arg.doit().num for arg in self.args) + _den_arg = (arg.doit().den for arg in self.args) + res_num = Mul(*_num_arg, evaluate=True) + res_den = Mul(*_den_arg, evaluate=True) + return TransferFunction(res_num, res_den, self.var) + + def _eval_rewrite_as_TransferFunction(self, *args, **kwargs): + return self.doit() + + @_check_other_SISO + def __add__(self, other): + + if isinstance(other, Parallel): + arg_list = list(other.args) + return Parallel(self, *arg_list) + + return Parallel(self, other) + + __radd__ = __add__ + + @_check_other_SISO + def __sub__(self, other): + return self + (-other) + + def __rsub__(self, other): + return -self + other + + @_check_other_SISO + def __mul__(self, other): + + arg_list = list(self.args) + return Series(*arg_list, other) + + def __truediv__(self, other): + if isinstance(other, TransferFunction): + return Series(*self.args, TransferFunction(other.den, other.num, other.var)) + elif isinstance(other, Series): + tf_self = self.rewrite(TransferFunction) + tf_other = other.rewrite(TransferFunction) + return tf_self / tf_other + elif (isinstance(other, Parallel) and len(other.args) == 2 + and isinstance(other.args[0], TransferFunction) and isinstance(other.args[1], Series)): + + if not self.var == other.var: + raise ValueError(filldedent(""" + All the transfer functions should use the same complex variable + of the Laplace transform.""")) + self_arg_list = set(self.args) + other_arg_list = set(other.args[1].args) + res = list(self_arg_list ^ other_arg_list) + if len(res) == 0: + return Feedback(self, other.args[0]) + elif len(res) == 1: + return Feedback(self, *res) + else: + return Feedback(self, Series(*res)) + else: + raise ValueError("This transfer function expression is invalid.") + + def __neg__(self): + return Series(TransferFunction(-1, 1, self.var), self) + + def to_expr(self): + """Returns the equivalent ``Expr`` object.""" + return Mul(*(arg.to_expr() for arg in self.args), evaluate=False) + + @property + def is_proper(self): + """ + Returns True if degree of the numerator polynomial of the resultant transfer + function is less than or equal to degree of the denominator polynomial of + the same, else False. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction, Series + >>> tf1 = TransferFunction(b*s**2 + p**2 - a*p + s, b - p**2, s) + >>> tf2 = TransferFunction(p**2 - 4*p, p**3 + 3*s + 2, s) + >>> tf3 = TransferFunction(s, s**2 + s + 1, s) + >>> S1 = Series(-tf2, tf1) + >>> S1.is_proper + False + >>> S2 = Series(tf1, tf2, tf3) + >>> S2.is_proper + True + + """ + return self.doit().is_proper + + @property + def is_strictly_proper(self): + """ + Returns True if degree of the numerator polynomial of the resultant transfer + function is strictly less than degree of the denominator polynomial of + the same, else False. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction, Series + >>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s) + >>> tf2 = TransferFunction(s**3 - 2, s**2 + 5*s + 6, s) + >>> tf3 = TransferFunction(1, s**2 + s + 1, s) + >>> S1 = Series(tf1, tf2) + >>> S1.is_strictly_proper + False + >>> S2 = Series(tf1, tf2, tf3) + >>> S2.is_strictly_proper + True + + """ + return self.doit().is_strictly_proper + + @property + def is_biproper(self): + r""" + Returns True if degree of the numerator polynomial of the resultant transfer + function is equal to degree of the denominator polynomial of + the same, else False. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction, Series + >>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s) + >>> tf2 = TransferFunction(p, s**2, s) + >>> tf3 = TransferFunction(s**2, 1, s) + >>> S1 = Series(tf1, -tf2) + >>> S1.is_biproper + False + >>> S2 = Series(tf2, tf3) + >>> S2.is_biproper + True + + """ + return self.doit().is_biproper + + +def _mat_mul_compatible(*args): + """To check whether shapes are compatible for matrix mul.""" + return all(args[i].num_outputs == args[i+1].num_inputs for i in range(len(args)-1)) + + +class MIMOSeries(MIMOLinearTimeInvariant): + r""" + A class for representing a series configuration of MIMO systems. + + Parameters + ========== + + args : MIMOLinearTimeInvariant + MIMO systems in a series configuration. + evaluate : Boolean, Keyword + When passed ``True``, returns the equivalent + ``MIMOSeries(*args).doit()``. Set to ``False`` by default. + + Raises + ====== + + ValueError + When no argument is passed. + + ``var`` attribute is not same for every system. + + ``num_outputs`` of the MIMO system is not equal to the + ``num_inputs`` of its adjacent MIMO system. (Matrix + multiplication constraint, basically) + TypeError + Any of the passed ``*args`` has unsupported type + + A combination of SISO and MIMO systems is + passed. There should be homogeneity in the + type of systems passed, MIMO in this case. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import MIMOSeries, TransferFunctionMatrix + >>> from sympy import Matrix, pprint + >>> mat_a = Matrix([[5*s], [5]]) # 2 Outputs 1 Input + >>> mat_b = Matrix([[5, 1/(6*s**2)]]) # 1 Output 2 Inputs + >>> mat_c = Matrix([[1, s], [5/s, 1]]) # 2 Outputs 2 Inputs + >>> tfm_a = TransferFunctionMatrix.from_Matrix(mat_a, s) + >>> tfm_b = TransferFunctionMatrix.from_Matrix(mat_b, s) + >>> tfm_c = TransferFunctionMatrix.from_Matrix(mat_c, s) + >>> MIMOSeries(tfm_c, tfm_b, tfm_a) + MIMOSeries(TransferFunctionMatrix(((TransferFunction(1, 1, s), TransferFunction(s, 1, s)), (TransferFunction(5, s, s), TransferFunction(1, 1, s)))), TransferFunctionMatrix(((TransferFunction(5, 1, s), TransferFunction(1, 6*s**2, s)),)), TransferFunctionMatrix(((TransferFunction(5*s, 1, s),), (TransferFunction(5, 1, s),)))) + >>> pprint(_, use_unicode=False) # For Better Visualization + [5*s] [1 s] + [---] [5 1 ] [- -] + [ 1 ] [- ----] [1 1] + [ ] *[1 2] *[ ] + [ 5 ] [ 6*s ]{t} [5 1] + [ - ] [- -] + [ 1 ]{t} [s 1]{t} + >>> MIMOSeries(tfm_c, tfm_b, tfm_a).doit() + TransferFunctionMatrix(((TransferFunction(150*s**4 + 25*s, 6*s**3, s), TransferFunction(150*s**4 + 5*s, 6*s**2, s)), (TransferFunction(150*s**3 + 25, 6*s**3, s), TransferFunction(150*s**3 + 5, 6*s**2, s)))) + >>> pprint(_, use_unicode=False) # (2 Inputs -A-> 2 Outputs) -> (2 Inputs -B-> 1 Output) -> (1 Input -C-> 2 Outputs) is equivalent to (2 Inputs -Series Equivalent-> 2 Outputs). + [ 4 4 ] + [150*s + 25*s 150*s + 5*s] + [------------- ------------] + [ 3 2 ] + [ 6*s 6*s ] + [ ] + [ 3 3 ] + [ 150*s + 25 150*s + 5 ] + [ ----------- ---------- ] + [ 3 2 ] + [ 6*s 6*s ]{t} + + Notes + ===== + + All the transfer function matrices should use the same complex variable ``var`` of the Laplace transform. + + ``MIMOSeries(A, B)`` is not equivalent to ``A*B``. It is always in the reverse order, that is ``B*A``. + + See Also + ======== + + Series, MIMOParallel + + """ + def __new__(cls, *args, evaluate=False): + + cls._check_args(args) + + if _mat_mul_compatible(*args): + obj = super().__new__(cls, *args) + + else: + raise ValueError(filldedent(""" + Number of input signals do not match the number + of output signals of adjacent systems for some args.""")) + + return obj.doit() if evaluate else obj + + @property + def var(self): + """ + Returns the complex variable used by all the transfer functions. + + Examples + ======== + + >>> from sympy.abc import p + >>> from sympy.physics.control.lti import TransferFunction, MIMOSeries, TransferFunctionMatrix + >>> G1 = TransferFunction(p**2 + 2*p + 4, p - 6, p) + >>> G2 = TransferFunction(p, 4 - p, p) + >>> G3 = TransferFunction(0, p**4 - 1, p) + >>> tfm_1 = TransferFunctionMatrix([[G1, G2, G3]]) + >>> tfm_2 = TransferFunctionMatrix([[G1], [G2], [G3]]) + >>> MIMOSeries(tfm_2, tfm_1).var + p + + """ + return self.args[0].var + + @property + def num_inputs(self): + """Returns the number of input signals of the series system.""" + return self.args[0].num_inputs + + @property + def num_outputs(self): + """Returns the number of output signals of the series system.""" + return self.args[-1].num_outputs + + @property + def shape(self): + """Returns the shape of the equivalent MIMO system.""" + return self.num_outputs, self.num_inputs + + def doit(self, cancel=False, **kwargs): + """ + Returns the resultant transfer function matrix obtained after evaluating + the MIMO systems arranged in a series configuration. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction, MIMOSeries, TransferFunctionMatrix + >>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s) + >>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s) + >>> tfm1 = TransferFunctionMatrix([[tf1, tf2], [tf2, tf2]]) + >>> tfm2 = TransferFunctionMatrix([[tf2, tf1], [tf1, tf1]]) + >>> MIMOSeries(tfm2, tfm1).doit() + TransferFunctionMatrix(((TransferFunction(2*(-p + s)*(s**3 - 2)*(a*p**2 + b*s)*(s**4 + 5*s + 6), (-p + s)**2*(s**4 + 5*s + 6)**2, s), TransferFunction((-p + s)**2*(s**3 - 2)*(a*p**2 + b*s) + (-p + s)*(a*p**2 + b*s)**2*(s**4 + 5*s + 6), (-p + s)**3*(s**4 + 5*s + 6), s)), (TransferFunction((-p + s)*(s**3 - 2)**2*(s**4 + 5*s + 6) + (s**3 - 2)*(a*p**2 + b*s)*(s**4 + 5*s + 6)**2, (-p + s)*(s**4 + 5*s + 6)**3, s), TransferFunction(2*(s**3 - 2)*(a*p**2 + b*s), (-p + s)*(s**4 + 5*s + 6), s)))) + + """ + _arg = (arg.doit()._expr_mat for arg in reversed(self.args)) + + if cancel: + res = MatMul(*_arg, evaluate=True) + return TransferFunctionMatrix.from_Matrix(res, self.var) + + _dummy_args, _dummy_dict = _dummify_args(_arg, self.var) + res = MatMul(*_dummy_args, evaluate=True) + temp_tfm = TransferFunctionMatrix.from_Matrix(res, self.var) + return temp_tfm.subs(_dummy_dict) + + def _eval_rewrite_as_TransferFunctionMatrix(self, *args, **kwargs): + return self.doit() + + @_check_other_MIMO + def __add__(self, other): + + if isinstance(other, MIMOParallel): + arg_list = list(other.args) + return MIMOParallel(self, *arg_list) + + return MIMOParallel(self, other) + + __radd__ = __add__ + + @_check_other_MIMO + def __sub__(self, other): + return self + (-other) + + def __rsub__(self, other): + return -self + other + + @_check_other_MIMO + def __mul__(self, other): + + if isinstance(other, MIMOSeries): + self_arg_list = list(self.args) + other_arg_list = list(other.args) + return MIMOSeries(*other_arg_list, *self_arg_list) # A*B = MIMOSeries(B, A) + + arg_list = list(self.args) + return MIMOSeries(other, *arg_list) + + def __neg__(self): + arg_list = list(self.args) + arg_list[0] = -arg_list[0] + return MIMOSeries(*arg_list) + + +class Parallel(SISOLinearTimeInvariant): + r""" + A class for representing a parallel configuration of SISO systems. + + Parameters + ========== + + args : SISOLinearTimeInvariant + SISO systems in a parallel arrangement. + evaluate : Boolean, Keyword + When passed ``True``, returns the equivalent + ``Parallel(*args).doit()``. Set to ``False`` by default. + + Raises + ====== + + ValueError + When no argument is passed. + + ``var`` attribute is not same for every system. + TypeError + Any of the passed ``*args`` has unsupported type + + A combination of SISO and MIMO systems is + passed. There should be homogeneity in the + type of systems passed. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction, Parallel, Series + >>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s) + >>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s) + >>> tf3 = TransferFunction(p**2, p + s, s) + >>> P1 = Parallel(tf1, tf2) + >>> P1 + Parallel(TransferFunction(a*p**2 + b*s, -p + s, s), TransferFunction(s**3 - 2, s**4 + 5*s + 6, s)) + >>> P1.var + s + >>> P2 = Parallel(tf2, Series(tf3, -tf1)) + >>> P2 + Parallel(TransferFunction(s**3 - 2, s**4 + 5*s + 6, s), Series(TransferFunction(p**2, p + s, s), TransferFunction(-a*p**2 - b*s, -p + s, s))) + >>> P2.var + s + >>> P3 = Parallel(Series(tf1, tf2), Series(tf2, tf3)) + >>> P3 + Parallel(Series(TransferFunction(a*p**2 + b*s, -p + s, s), TransferFunction(s**3 - 2, s**4 + 5*s + 6, s)), Series(TransferFunction(s**3 - 2, s**4 + 5*s + 6, s), TransferFunction(p**2, p + s, s))) + >>> P3.var + s + + You can get the resultant transfer function by using ``.doit()`` method: + + >>> Parallel(tf1, tf2, -tf3).doit() + TransferFunction(-p**2*(-p + s)*(s**4 + 5*s + 6) + (-p + s)*(p + s)*(s**3 - 2) + (p + s)*(a*p**2 + b*s)*(s**4 + 5*s + 6), (-p + s)*(p + s)*(s**4 + 5*s + 6), s) + >>> Parallel(tf2, Series(tf1, -tf3)).doit() + TransferFunction(-p**2*(a*p**2 + b*s)*(s**4 + 5*s + 6) + (-p + s)*(p + s)*(s**3 - 2), (-p + s)*(p + s)*(s**4 + 5*s + 6), s) + + Notes + ===== + + All the transfer functions should use the same complex variable + ``var`` of the Laplace transform. + + See Also + ======== + + Series, TransferFunction, Feedback + + """ + def __new__(cls, *args, evaluate=False): + + args = _flatten_args(args, Parallel) + cls._check_args(args) + obj = super().__new__(cls, *args) + + return obj.doit() if evaluate else obj + + @property + def var(self): + """ + Returns the complex variable used by all the transfer functions. + + Examples + ======== + + >>> from sympy.abc import p + >>> from sympy.physics.control.lti import TransferFunction, Parallel, Series + >>> G1 = TransferFunction(p**2 + 2*p + 4, p - 6, p) + >>> G2 = TransferFunction(p, 4 - p, p) + >>> G3 = TransferFunction(0, p**4 - 1, p) + >>> Parallel(G1, G2).var + p + >>> Parallel(-G3, Series(G1, G2)).var + p + + """ + return self.args[0].var + + def doit(self, **hints): + """ + Returns the resultant transfer function obtained after evaluating + the transfer functions in parallel configuration. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction, Parallel + >>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s) + >>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s) + >>> Parallel(tf2, tf1).doit() + TransferFunction((-p + s)*(s**3 - 2) + (a*p**2 + b*s)*(s**4 + 5*s + 6), (-p + s)*(s**4 + 5*s + 6), s) + >>> Parallel(-tf1, -tf2).doit() + TransferFunction((2 - s**3)*(-p + s) + (-a*p**2 - b*s)*(s**4 + 5*s + 6), (-p + s)*(s**4 + 5*s + 6), s) + + """ + + _arg = (arg.doit().to_expr() for arg in self.args) + res = Add(*_arg).as_numer_denom() + return TransferFunction(*res, self.var) + + def _eval_rewrite_as_TransferFunction(self, *args, **kwargs): + return self.doit() + + @_check_other_SISO + def __add__(self, other): + + self_arg_list = list(self.args) + return Parallel(*self_arg_list, other) + + __radd__ = __add__ + + @_check_other_SISO + def __sub__(self, other): + return self + (-other) + + def __rsub__(self, other): + return -self + other + + @_check_other_SISO + def __mul__(self, other): + + if isinstance(other, Series): + arg_list = list(other.args) + return Series(self, *arg_list) + + return Series(self, other) + + def __neg__(self): + return Series(TransferFunction(-1, 1, self.var), self) + + def to_expr(self): + """Returns the equivalent ``Expr`` object.""" + return Add(*(arg.to_expr() for arg in self.args), evaluate=False) + + @property + def is_proper(self): + """ + Returns True if degree of the numerator polynomial of the resultant transfer + function is less than or equal to degree of the denominator polynomial of + the same, else False. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction, Parallel + >>> tf1 = TransferFunction(b*s**2 + p**2 - a*p + s, b - p**2, s) + >>> tf2 = TransferFunction(p**2 - 4*p, p**3 + 3*s + 2, s) + >>> tf3 = TransferFunction(s, s**2 + s + 1, s) + >>> P1 = Parallel(-tf2, tf1) + >>> P1.is_proper + False + >>> P2 = Parallel(tf2, tf3) + >>> P2.is_proper + True + + """ + return self.doit().is_proper + + @property + def is_strictly_proper(self): + """ + Returns True if degree of the numerator polynomial of the resultant transfer + function is strictly less than degree of the denominator polynomial of + the same, else False. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction, Parallel + >>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s) + >>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s) + >>> tf3 = TransferFunction(s, s**2 + s + 1, s) + >>> P1 = Parallel(tf1, tf2) + >>> P1.is_strictly_proper + False + >>> P2 = Parallel(tf2, tf3) + >>> P2.is_strictly_proper + True + + """ + return self.doit().is_strictly_proper + + @property + def is_biproper(self): + """ + Returns True if degree of the numerator polynomial of the resultant transfer + function is equal to degree of the denominator polynomial of + the same, else False. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction, Parallel + >>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s) + >>> tf2 = TransferFunction(p**2, p + s, s) + >>> tf3 = TransferFunction(s, s**2 + s + 1, s) + >>> P1 = Parallel(tf1, -tf2) + >>> P1.is_biproper + True + >>> P2 = Parallel(tf2, tf3) + >>> P2.is_biproper + False + + """ + return self.doit().is_biproper + + +class MIMOParallel(MIMOLinearTimeInvariant): + r""" + A class for representing a parallel configuration of MIMO systems. + + Parameters + ========== + + args : MIMOLinearTimeInvariant + MIMO Systems in a parallel arrangement. + evaluate : Boolean, Keyword + When passed ``True``, returns the equivalent + ``MIMOParallel(*args).doit()``. Set to ``False`` by default. + + Raises + ====== + + ValueError + When no argument is passed. + + ``var`` attribute is not same for every system. + + All MIMO systems passed do not have same shape. + TypeError + Any of the passed ``*args`` has unsupported type + + A combination of SISO and MIMO systems is + passed. There should be homogeneity in the + type of systems passed, MIMO in this case. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunctionMatrix, MIMOParallel + >>> from sympy import Matrix, pprint + >>> expr_1 = 1/s + >>> expr_2 = s/(s**2-1) + >>> expr_3 = (2 + s)/(s**2 - 1) + >>> expr_4 = 5 + >>> tfm_a = TransferFunctionMatrix.from_Matrix(Matrix([[expr_1, expr_2], [expr_3, expr_4]]), s) + >>> tfm_b = TransferFunctionMatrix.from_Matrix(Matrix([[expr_2, expr_1], [expr_4, expr_3]]), s) + >>> tfm_c = TransferFunctionMatrix.from_Matrix(Matrix([[expr_3, expr_4], [expr_1, expr_2]]), s) + >>> MIMOParallel(tfm_a, tfm_b, tfm_c) + MIMOParallel(TransferFunctionMatrix(((TransferFunction(1, s, s), TransferFunction(s, s**2 - 1, s)), (TransferFunction(s + 2, s**2 - 1, s), TransferFunction(5, 1, s)))), TransferFunctionMatrix(((TransferFunction(s, s**2 - 1, s), TransferFunction(1, s, s)), (TransferFunction(5, 1, s), TransferFunction(s + 2, s**2 - 1, s)))), TransferFunctionMatrix(((TransferFunction(s + 2, s**2 - 1, s), TransferFunction(5, 1, s)), (TransferFunction(1, s, s), TransferFunction(s, s**2 - 1, s))))) + >>> pprint(_, use_unicode=False) # For Better Visualization + [ 1 s ] [ s 1 ] [s + 2 5 ] + [ - ------] [------ - ] [------ - ] + [ s 2 ] [ 2 s ] [ 2 1 ] + [ s - 1] [s - 1 ] [s - 1 ] + [ ] + [ ] + [ ] + [s + 2 5 ] [ 5 s + 2 ] [ 1 s ] + [------ - ] [ - ------] [ - ------] + [ 2 1 ] [ 1 2 ] [ s 2 ] + [s - 1 ]{t} [ s - 1]{t} [ s - 1]{t} + >>> MIMOParallel(tfm_a, tfm_b, tfm_c).doit() + TransferFunctionMatrix(((TransferFunction(s**2 + s*(2*s + 2) - 1, s*(s**2 - 1), s), TransferFunction(2*s**2 + 5*s*(s**2 - 1) - 1, s*(s**2 - 1), s)), (TransferFunction(s**2 + s*(s + 2) + 5*s*(s**2 - 1) - 1, s*(s**2 - 1), s), TransferFunction(5*s**2 + 2*s - 3, s**2 - 1, s)))) + >>> pprint(_, use_unicode=False) + [ 2 2 / 2 \ ] + [ s + s*(2*s + 2) - 1 2*s + 5*s*\s - 1/ - 1] + [ -------------------- -----------------------] + [ / 2 \ / 2 \ ] + [ s*\s - 1/ s*\s - 1/ ] + [ ] + [ 2 / 2 \ 2 ] + [s + s*(s + 2) + 5*s*\s - 1/ - 1 5*s + 2*s - 3 ] + [--------------------------------- -------------- ] + [ / 2 \ 2 ] + [ s*\s - 1/ s - 1 ]{t} + + Notes + ===== + + All the transfer function matrices should use the same complex variable + ``var`` of the Laplace transform. + + See Also + ======== + + Parallel, MIMOSeries + + """ + def __new__(cls, *args, evaluate=False): + + args = _flatten_args(args, MIMOParallel) + + cls._check_args(args) + + if any(arg.shape != args[0].shape for arg in args): + raise TypeError("Shape of all the args is not equal.") + + obj = super().__new__(cls, *args) + + return obj.doit() if evaluate else obj + + @property + def var(self): + """ + Returns the complex variable used by all the systems. + + Examples + ======== + + >>> from sympy.abc import p + >>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, MIMOParallel + >>> G1 = TransferFunction(p**2 + 2*p + 4, p - 6, p) + >>> G2 = TransferFunction(p, 4 - p, p) + >>> G3 = TransferFunction(0, p**4 - 1, p) + >>> G4 = TransferFunction(p**2, p**2 - 1, p) + >>> tfm_a = TransferFunctionMatrix([[G1, G2], [G3, G4]]) + >>> tfm_b = TransferFunctionMatrix([[G2, G1], [G4, G3]]) + >>> MIMOParallel(tfm_a, tfm_b).var + p + + """ + return self.args[0].var + + @property + def num_inputs(self): + """Returns the number of input signals of the parallel system.""" + return self.args[0].num_inputs + + @property + def num_outputs(self): + """Returns the number of output signals of the parallel system.""" + return self.args[0].num_outputs + + @property + def shape(self): + """Returns the shape of the equivalent MIMO system.""" + return self.num_outputs, self.num_inputs + + def doit(self, **hints): + """ + Returns the resultant transfer function matrix obtained after evaluating + the MIMO systems arranged in a parallel configuration. + + Examples + ======== + + >>> from sympy.abc import s, p, a, b + >>> from sympy.physics.control.lti import TransferFunction, MIMOParallel, TransferFunctionMatrix + >>> tf1 = TransferFunction(a*p**2 + b*s, s - p, s) + >>> tf2 = TransferFunction(s**3 - 2, s**4 + 5*s + 6, s) + >>> tfm_1 = TransferFunctionMatrix([[tf1, tf2], [tf2, tf1]]) + >>> tfm_2 = TransferFunctionMatrix([[tf2, tf1], [tf1, tf2]]) + >>> MIMOParallel(tfm_1, tfm_2).doit() + TransferFunctionMatrix(((TransferFunction((-p + s)*(s**3 - 2) + (a*p**2 + b*s)*(s**4 + 5*s + 6), (-p + s)*(s**4 + 5*s + 6), s), TransferFunction((-p + s)*(s**3 - 2) + (a*p**2 + b*s)*(s**4 + 5*s + 6), (-p + s)*(s**4 + 5*s + 6), s)), (TransferFunction((-p + s)*(s**3 - 2) + (a*p**2 + b*s)*(s**4 + 5*s + 6), (-p + s)*(s**4 + 5*s + 6), s), TransferFunction((-p + s)*(s**3 - 2) + (a*p**2 + b*s)*(s**4 + 5*s + 6), (-p + s)*(s**4 + 5*s + 6), s)))) + + """ + _arg = (arg.doit()._expr_mat for arg in self.args) + res = MatAdd(*_arg, evaluate=True) + return TransferFunctionMatrix.from_Matrix(res, self.var) + + def _eval_rewrite_as_TransferFunctionMatrix(self, *args, **kwargs): + return self.doit() + + @_check_other_MIMO + def __add__(self, other): + + self_arg_list = list(self.args) + return MIMOParallel(*self_arg_list, other) + + __radd__ = __add__ + + @_check_other_MIMO + def __sub__(self, other): + return self + (-other) + + def __rsub__(self, other): + return -self + other + + @_check_other_MIMO + def __mul__(self, other): + + if isinstance(other, MIMOSeries): + arg_list = list(other.args) + return MIMOSeries(*arg_list, self) + + return MIMOSeries(other, self) + + def __neg__(self): + arg_list = [-arg for arg in list(self.args)] + return MIMOParallel(*arg_list) + + +class Feedback(TransferFunction): + r""" + A class for representing closed-loop feedback interconnection between two + SISO input/output systems. + + The first argument, ``sys1``, is the feedforward part of the closed-loop + system or in simple words, the dynamical model representing the process + to be controlled. The second argument, ``sys2``, is the feedback system + and controls the fed back signal to ``sys1``. Both ``sys1`` and ``sys2`` + can either be ``Series`` or ``TransferFunction`` objects. + + Parameters + ========== + + sys1 : Series, TransferFunction + The feedforward path system. + sys2 : Series, TransferFunction, optional + The feedback path system (often a feedback controller). + It is the model sitting on the feedback path. + + If not specified explicitly, the sys2 is + assumed to be unit (1.0) transfer function. + sign : int, optional + The sign of feedback. Can either be ``1`` + (for positive feedback) or ``-1`` (for negative feedback). + Default value is `-1`. + + Raises + ====== + + ValueError + When ``sys1`` and ``sys2`` are not using the + same complex variable of the Laplace transform. + + When a combination of ``sys1`` and ``sys2`` yields + zero denominator. + + TypeError + When either ``sys1`` or ``sys2`` is not a ``Series`` or a + ``TransferFunction`` object. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction, Feedback + >>> plant = TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s) + >>> controller = TransferFunction(5*s - 10, s + 7, s) + >>> F1 = Feedback(plant, controller) + >>> F1 + Feedback(TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s), TransferFunction(5*s - 10, s + 7, s), -1) + >>> F1.var + s + >>> F1.args + (TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s), TransferFunction(5*s - 10, s + 7, s), -1) + + You can get the feedforward and feedback path systems by using ``.sys1`` and ``.sys2`` respectively. + + >>> F1.sys1 + TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s) + >>> F1.sys2 + TransferFunction(5*s - 10, s + 7, s) + + You can get the resultant closed loop transfer function obtained by negative feedback + interconnection using ``.doit()`` method. + + >>> F1.doit() + TransferFunction((s + 7)*(s**2 - 4*s + 2)*(3*s**2 + 7*s - 3), ((s + 7)*(s**2 - 4*s + 2) + (5*s - 10)*(3*s**2 + 7*s - 3))*(s**2 - 4*s + 2), s) + >>> G = TransferFunction(2*s**2 + 5*s + 1, s**2 + 2*s + 3, s) + >>> C = TransferFunction(5*s + 10, s + 10, s) + >>> F2 = Feedback(G*C, TransferFunction(1, 1, s)) + >>> F2.doit() + TransferFunction((s + 10)*(5*s + 10)*(s**2 + 2*s + 3)*(2*s**2 + 5*s + 1), (s + 10)*((s + 10)*(s**2 + 2*s + 3) + (5*s + 10)*(2*s**2 + 5*s + 1))*(s**2 + 2*s + 3), s) + + To negate a ``Feedback`` object, the ``-`` operator can be prepended: + + >>> -F1 + Feedback(TransferFunction(-3*s**2 - 7*s + 3, s**2 - 4*s + 2, s), TransferFunction(10 - 5*s, s + 7, s), -1) + >>> -F2 + Feedback(Series(TransferFunction(-1, 1, s), TransferFunction(2*s**2 + 5*s + 1, s**2 + 2*s + 3, s), TransferFunction(5*s + 10, s + 10, s)), TransferFunction(-1, 1, s), -1) + + See Also + ======== + + MIMOFeedback, Series, Parallel + + """ + def __new__(cls, sys1, sys2=None, sign=-1): + if not sys2: + sys2 = TransferFunction(1, 1, sys1.var) + + if not (isinstance(sys1, (TransferFunction, Series, Feedback)) + and isinstance(sys2, (TransferFunction, Series, Feedback))): + raise TypeError("Unsupported type for `sys1` or `sys2` of Feedback.") + + if sign not in [-1, 1]: + raise ValueError(filldedent(""" + Unsupported type for feedback. `sign` arg should + either be 1 (positive feedback loop) or -1 + (negative feedback loop).""")) + + if Mul(sys1.to_expr(), sys2.to_expr()).simplify() == sign: + raise ValueError("The equivalent system will have zero denominator.") + + if sys1.var != sys2.var: + raise ValueError(filldedent(""" + Both `sys1` and `sys2` should be using the + same complex variable.""")) + + return super(TransferFunction, cls).__new__(cls, sys1, sys2, _sympify(sign)) + + @property + def sys1(self): + """ + Returns the feedforward system of the feedback interconnection. + + Examples + ======== + + >>> from sympy.abc import s, p + >>> from sympy.physics.control.lti import TransferFunction, Feedback + >>> plant = TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s) + >>> controller = TransferFunction(5*s - 10, s + 7, s) + >>> F1 = Feedback(plant, controller) + >>> F1.sys1 + TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s) + >>> G = TransferFunction(2*s**2 + 5*s + 1, p**2 + 2*p + 3, p) + >>> C = TransferFunction(5*p + 10, p + 10, p) + >>> P = TransferFunction(1 - s, p + 2, p) + >>> F2 = Feedback(TransferFunction(1, 1, p), G*C*P) + >>> F2.sys1 + TransferFunction(1, 1, p) + + """ + return self.args[0] + + @property + def sys2(self): + """ + Returns the feedback controller of the feedback interconnection. + + Examples + ======== + + >>> from sympy.abc import s, p + >>> from sympy.physics.control.lti import TransferFunction, Feedback + >>> plant = TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s) + >>> controller = TransferFunction(5*s - 10, s + 7, s) + >>> F1 = Feedback(plant, controller) + >>> F1.sys2 + TransferFunction(5*s - 10, s + 7, s) + >>> G = TransferFunction(2*s**2 + 5*s + 1, p**2 + 2*p + 3, p) + >>> C = TransferFunction(5*p + 10, p + 10, p) + >>> P = TransferFunction(1 - s, p + 2, p) + >>> F2 = Feedback(TransferFunction(1, 1, p), G*C*P) + >>> F2.sys2 + Series(TransferFunction(2*s**2 + 5*s + 1, p**2 + 2*p + 3, p), TransferFunction(5*p + 10, p + 10, p), TransferFunction(1 - s, p + 2, p)) + + """ + return self.args[1] + + @property + def var(self): + """ + Returns the complex variable of the Laplace transform used by all + the transfer functions involved in the feedback interconnection. + + Examples + ======== + + >>> from sympy.abc import s, p + >>> from sympy.physics.control.lti import TransferFunction, Feedback + >>> plant = TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s) + >>> controller = TransferFunction(5*s - 10, s + 7, s) + >>> F1 = Feedback(plant, controller) + >>> F1.var + s + >>> G = TransferFunction(2*s**2 + 5*s + 1, p**2 + 2*p + 3, p) + >>> C = TransferFunction(5*p + 10, p + 10, p) + >>> P = TransferFunction(1 - s, p + 2, p) + >>> F2 = Feedback(TransferFunction(1, 1, p), G*C*P) + >>> F2.var + p + + """ + return self.sys1.var + + @property + def sign(self): + """ + Returns the type of MIMO Feedback model. ``1`` + for Positive and ``-1`` for Negative. + """ + return self.args[2] + + @property + def num(self): + """ + Returns the numerator of the closed loop feedback system. + """ + return self.sys1 + + @property + def den(self): + """ + Returns the denominator of the closed loop feedback model. + """ + unit = TransferFunction(1, 1, self.var) + arg_list = list(self.sys1.args) if isinstance(self.sys1, Series) else [self.sys1] + if self.sign == 1: + return Parallel(unit, -Series(self.sys2, *arg_list)) + return Parallel(unit, Series(self.sys2, *arg_list)) + + @property + def sensitivity(self): + """ + Returns the sensitivity function of the feedback loop. + + Sensitivity of a Feedback system is the ratio + of change in the open loop gain to the change in + the closed loop gain. + + .. note:: + This method would not return the complementary + sensitivity function. + + Examples + ======== + + >>> from sympy.abc import p + >>> from sympy.physics.control.lti import TransferFunction, Feedback + >>> C = TransferFunction(5*p + 10, p + 10, p) + >>> P = TransferFunction(1 - p, p + 2, p) + >>> F_1 = Feedback(P, C) + >>> F_1.sensitivity + 1/((1 - p)*(5*p + 10)/((p + 2)*(p + 10)) + 1) + + """ + + return 1/(1 - self.sign*self.sys1.to_expr()*self.sys2.to_expr()) + + def doit(self, cancel=False, expand=False, **hints): + """ + Returns the resultant transfer function obtained by the + feedback interconnection. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction, Feedback + >>> plant = TransferFunction(3*s**2 + 7*s - 3, s**2 - 4*s + 2, s) + >>> controller = TransferFunction(5*s - 10, s + 7, s) + >>> F1 = Feedback(plant, controller) + >>> F1.doit() + TransferFunction((s + 7)*(s**2 - 4*s + 2)*(3*s**2 + 7*s - 3), ((s + 7)*(s**2 - 4*s + 2) + (5*s - 10)*(3*s**2 + 7*s - 3))*(s**2 - 4*s + 2), s) + >>> G = TransferFunction(2*s**2 + 5*s + 1, s**2 + 2*s + 3, s) + >>> F2 = Feedback(G, TransferFunction(1, 1, s)) + >>> F2.doit() + TransferFunction((s**2 + 2*s + 3)*(2*s**2 + 5*s + 1), (s**2 + 2*s + 3)*(3*s**2 + 7*s + 4), s) + + Use kwarg ``expand=True`` to expand the resultant transfer function. + Use ``cancel=True`` to cancel out the common terms in numerator and + denominator. + + >>> F2.doit(cancel=True, expand=True) + TransferFunction(2*s**2 + 5*s + 1, 3*s**2 + 7*s + 4, s) + >>> F2.doit(expand=True) + TransferFunction(2*s**4 + 9*s**3 + 17*s**2 + 17*s + 3, 3*s**4 + 13*s**3 + 27*s**2 + 29*s + 12, s) + + """ + arg_list = list(self.sys1.args) if isinstance(self.sys1, Series) else [self.sys1] + # F_n and F_d are resultant TFs of num and den of Feedback. + F_n, unit = self.sys1.doit(), TransferFunction(1, 1, self.sys1.var) + if self.sign == -1: + F_d = Parallel(unit, Series(self.sys2, *arg_list)).doit() + else: + F_d = Parallel(unit, -Series(self.sys2, *arg_list)).doit() + + _resultant_tf = TransferFunction(F_n.num * F_d.den, F_n.den * F_d.num, F_n.var) + + if cancel: + _resultant_tf = _resultant_tf.simplify() + + if expand: + _resultant_tf = _resultant_tf.expand() + + return _resultant_tf + + def _eval_rewrite_as_TransferFunction(self, num, den, sign, **kwargs): + return self.doit() + + def to_expr(self): + """ + Converts a ``Feedback`` object to SymPy Expr. + + Examples + ======== + + >>> from sympy.abc import s, a, b + >>> from sympy.physics.control.lti import TransferFunction, Feedback + >>> from sympy import Expr + >>> tf1 = TransferFunction(a+s, 1, s) + >>> tf2 = TransferFunction(b+s, 1, s) + >>> fd1 = Feedback(tf1, tf2) + >>> fd1.to_expr() + (a + s)/((a + s)*(b + s) + 1) + >>> isinstance(_, Expr) + True + """ + + return self.doit().to_expr() + + def __neg__(self): + return Feedback(-self.sys1, -self.sys2, self.sign) + + +def _is_invertible(a, b, sign): + """ + Checks whether a given pair of MIMO + systems passed is invertible or not. + """ + _mat = eye(a.num_outputs) - sign*(a.doit()._expr_mat)*(b.doit()._expr_mat) + _det = _mat.det() + + return _det != 0 + + +class MIMOFeedback(MIMOLinearTimeInvariant): + r""" + A class for representing closed-loop feedback interconnection between two + MIMO input/output systems. + + Parameters + ========== + + sys1 : MIMOSeries, TransferFunctionMatrix + The MIMO system placed on the feedforward path. + sys2 : MIMOSeries, TransferFunctionMatrix + The system placed on the feedback path + (often a feedback controller). + sign : int, optional + The sign of feedback. Can either be ``1`` + (for positive feedback) or ``-1`` (for negative feedback). + Default value is `-1`. + + Raises + ====== + + ValueError + When ``sys1`` and ``sys2`` are not using the + same complex variable of the Laplace transform. + + Forward path model should have an equal number of inputs/outputs + to the feedback path outputs/inputs. + + When product of ``sys1`` and ``sys2`` is not a square matrix. + + When the equivalent MIMO system is not invertible. + + TypeError + When either ``sys1`` or ``sys2`` is not a ``MIMOSeries`` or a + ``TransferFunctionMatrix`` object. + + Examples + ======== + + >>> from sympy import Matrix, pprint + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunctionMatrix, MIMOFeedback + >>> plant_mat = Matrix([[1, 1/s], [0, 1]]) + >>> controller_mat = Matrix([[10, 0], [0, 10]]) # Constant Gain + >>> plant = TransferFunctionMatrix.from_Matrix(plant_mat, s) + >>> controller = TransferFunctionMatrix.from_Matrix(controller_mat, s) + >>> feedback = MIMOFeedback(plant, controller) # Negative Feedback (default) + >>> pprint(feedback, use_unicode=False) + / [1 1] [10 0 ] \-1 [1 1] + | [- -] [-- - ] | [- -] + | [1 s] [1 1 ] | [1 s] + |I + [ ] *[ ] | * [ ] + | [0 1] [0 10] | [0 1] + | [- -] [- --] | [- -] + \ [1 1]{t} [1 1 ]{t}/ [1 1]{t} + + To get the equivalent system matrix, use either ``doit`` or ``rewrite`` method. + + >>> pprint(feedback.doit(), use_unicode=False) + [1 1 ] + [-- -----] + [11 121*s] + [ ] + [0 1 ] + [- -- ] + [1 11 ]{t} + + To negate the ``MIMOFeedback`` object, use ``-`` operator. + + >>> neg_feedback = -feedback + >>> pprint(neg_feedback.doit(), use_unicode=False) + [-1 -1 ] + [--- -----] + [11 121*s] + [ ] + [ 0 -1 ] + [ - --- ] + [ 1 11 ]{t} + + See Also + ======== + + Feedback, MIMOSeries, MIMOParallel + + """ + def __new__(cls, sys1, sys2, sign=-1): + if not (isinstance(sys1, (TransferFunctionMatrix, MIMOSeries)) + and isinstance(sys2, (TransferFunctionMatrix, MIMOSeries))): + raise TypeError("Unsupported type for `sys1` or `sys2` of MIMO Feedback.") + + if sys1.num_inputs != sys2.num_outputs or \ + sys1.num_outputs != sys2.num_inputs: + raise ValueError(filldedent(""" + Product of `sys1` and `sys2` must + yield a square matrix.""")) + + if sign not in (-1, 1): + raise ValueError(filldedent(""" + Unsupported type for feedback. `sign` arg should + either be 1 (positive feedback loop) or -1 + (negative feedback loop).""")) + + if not _is_invertible(sys1, sys2, sign): + raise ValueError("Non-Invertible system inputted.") + if sys1.var != sys2.var: + raise ValueError(filldedent(""" + Both `sys1` and `sys2` should be using the + same complex variable.""")) + + return super().__new__(cls, sys1, sys2, _sympify(sign)) + + @property + def sys1(self): + r""" + Returns the system placed on the feedforward path of the MIMO feedback interconnection. + + Examples + ======== + + >>> from sympy import pprint + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, MIMOFeedback + >>> tf1 = TransferFunction(s**2 + s + 1, s**2 - s + 1, s) + >>> tf2 = TransferFunction(1, s, s) + >>> tf3 = TransferFunction(1, 1, s) + >>> sys1 = TransferFunctionMatrix([[tf1, tf2], [tf2, tf1]]) + >>> sys2 = TransferFunctionMatrix([[tf3, tf3], [tf3, tf2]]) + >>> F_1 = MIMOFeedback(sys1, sys2, 1) + >>> F_1.sys1 + TransferFunctionMatrix(((TransferFunction(s**2 + s + 1, s**2 - s + 1, s), TransferFunction(1, s, s)), (TransferFunction(1, s, s), TransferFunction(s**2 + s + 1, s**2 - s + 1, s)))) + >>> pprint(_, use_unicode=False) + [ 2 ] + [s + s + 1 1 ] + [---------- - ] + [ 2 s ] + [s - s + 1 ] + [ ] + [ 2 ] + [ 1 s + s + 1] + [ - ----------] + [ s 2 ] + [ s - s + 1]{t} + + """ + return self.args[0] + + @property + def sys2(self): + r""" + Returns the feedback controller of the MIMO feedback interconnection. + + Examples + ======== + + >>> from sympy import pprint + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, MIMOFeedback + >>> tf1 = TransferFunction(s**2, s**3 - s + 1, s) + >>> tf2 = TransferFunction(1, s, s) + >>> tf3 = TransferFunction(1, 1, s) + >>> sys1 = TransferFunctionMatrix([[tf1, tf2], [tf2, tf1]]) + >>> sys2 = TransferFunctionMatrix([[tf1, tf3], [tf3, tf2]]) + >>> F_1 = MIMOFeedback(sys1, sys2) + >>> F_1.sys2 + TransferFunctionMatrix(((TransferFunction(s**2, s**3 - s + 1, s), TransferFunction(1, 1, s)), (TransferFunction(1, 1, s), TransferFunction(1, s, s)))) + >>> pprint(_, use_unicode=False) + [ 2 ] + [ s 1] + [---------- -] + [ 3 1] + [s - s + 1 ] + [ ] + [ 1 1] + [ - -] + [ 1 s]{t} + + """ + return self.args[1] + + @property + def var(self): + r""" + Returns the complex variable of the Laplace transform used by all + the transfer functions involved in the MIMO feedback loop. + + Examples + ======== + + >>> from sympy.abc import p + >>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, MIMOFeedback + >>> tf1 = TransferFunction(p, 1 - p, p) + >>> tf2 = TransferFunction(1, p, p) + >>> tf3 = TransferFunction(1, 1, p) + >>> sys1 = TransferFunctionMatrix([[tf1, tf2], [tf2, tf1]]) + >>> sys2 = TransferFunctionMatrix([[tf1, tf3], [tf3, tf2]]) + >>> F_1 = MIMOFeedback(sys1, sys2, 1) # Positive feedback + >>> F_1.var + p + + """ + return self.sys1.var + + @property + def sign(self): + r""" + Returns the type of feedback interconnection of two models. ``1`` + for Positive and ``-1`` for Negative. + """ + return self.args[2] + + @property + def sensitivity(self): + r""" + Returns the sensitivity function matrix of the feedback loop. + + Sensitivity of a closed-loop system is the ratio of change + in the open loop gain to the change in the closed loop gain. + + .. note:: + This method would not return the complementary + sensitivity function. + + Examples + ======== + + >>> from sympy import pprint + >>> from sympy.abc import p + >>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, MIMOFeedback + >>> tf1 = TransferFunction(p, 1 - p, p) + >>> tf2 = TransferFunction(1, p, p) + >>> tf3 = TransferFunction(1, 1, p) + >>> sys1 = TransferFunctionMatrix([[tf1, tf2], [tf2, tf1]]) + >>> sys2 = TransferFunctionMatrix([[tf1, tf3], [tf3, tf2]]) + >>> F_1 = MIMOFeedback(sys1, sys2, 1) # Positive feedback + >>> F_2 = MIMOFeedback(sys1, sys2) # Negative feedback + >>> pprint(F_1.sensitivity, use_unicode=False) + [ 4 3 2 5 4 2 ] + [- p + 3*p - 4*p + 3*p - 1 p - 2*p + 3*p - 3*p + 1 ] + [---------------------------- -----------------------------] + [ 4 3 2 5 4 3 2 ] + [ p + 3*p - 8*p + 8*p - 3 p + 3*p - 8*p + 8*p - 3*p] + [ ] + [ 4 3 2 3 2 ] + [ p - p - p + p 3*p - 6*p + 4*p - 1 ] + [ -------------------------- -------------------------- ] + [ 4 3 2 4 3 2 ] + [ p + 3*p - 8*p + 8*p - 3 p + 3*p - 8*p + 8*p - 3 ] + >>> pprint(F_2.sensitivity, use_unicode=False) + [ 4 3 2 5 4 2 ] + [p - 3*p + 2*p + p - 1 p - 2*p + 3*p - 3*p + 1] + [------------------------ --------------------------] + [ 4 3 5 4 2 ] + [ p - 3*p + 2*p - 1 p - 3*p + 2*p - p ] + [ ] + [ 4 3 2 4 3 ] + [ p - p - p + p 2*p - 3*p + 2*p - 1 ] + [ ------------------- --------------------- ] + [ 4 3 4 3 ] + [ p - 3*p + 2*p - 1 p - 3*p + 2*p - 1 ] + + """ + _sys1_mat = self.sys1.doit()._expr_mat + _sys2_mat = self.sys2.doit()._expr_mat + + return (eye(self.sys1.num_inputs) - \ + self.sign*_sys1_mat*_sys2_mat).inv() + + def doit(self, cancel=True, expand=False, **hints): + r""" + Returns the resultant transfer function matrix obtained by the + feedback interconnection. + + Examples + ======== + + >>> from sympy import pprint + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, MIMOFeedback + >>> tf1 = TransferFunction(s, 1 - s, s) + >>> tf2 = TransferFunction(1, s, s) + >>> tf3 = TransferFunction(5, 1, s) + >>> tf4 = TransferFunction(s - 1, s, s) + >>> tf5 = TransferFunction(0, 1, s) + >>> sys1 = TransferFunctionMatrix([[tf1, tf2], [tf3, tf4]]) + >>> sys2 = TransferFunctionMatrix([[tf3, tf5], [tf5, tf5]]) + >>> F_1 = MIMOFeedback(sys1, sys2, 1) + >>> pprint(F_1, use_unicode=False) + / [ s 1 ] [5 0] \-1 [ s 1 ] + | [----- - ] [- -] | [----- - ] + | [1 - s s ] [1 1] | [1 - s s ] + |I - [ ] *[ ] | * [ ] + | [ 5 s - 1] [0 0] | [ 5 s - 1] + | [ - -----] [- -] | [ - -----] + \ [ 1 s ]{t} [1 1]{t}/ [ 1 s ]{t} + >>> pprint(F_1.doit(), use_unicode=False) + [ -s s - 1 ] + [------- ----------- ] + [6*s - 1 s*(6*s - 1) ] + [ ] + [5*s - 5 (s - 1)*(6*s + 24)] + [------- ------------------] + [6*s - 1 s*(6*s - 1) ]{t} + + If the user wants the resultant ``TransferFunctionMatrix`` object without + canceling the common factors then the ``cancel`` kwarg should be passed ``False``. + + >>> pprint(F_1.doit(cancel=False), use_unicode=False) + [ s*(s - 1) s - 1 ] + [ ----------------- ----------- ] + [ (1 - s)*(6*s - 1) s*(6*s - 1) ] + [ ] + [s*(25*s - 25) + 5*(1 - s)*(6*s - 1) s*(s - 1)*(6*s - 1) + s*(25*s - 25)] + [----------------------------------- -----------------------------------] + [ (1 - s)*(6*s - 1) 2 ] + [ s *(6*s - 1) ]{t} + + If the user wants the expanded form of the resultant transfer function matrix, + the ``expand`` kwarg should be passed as ``True``. + + >>> pprint(F_1.doit(expand=True), use_unicode=False) + [ -s s - 1 ] + [------- -------- ] + [6*s - 1 2 ] + [ 6*s - s ] + [ ] + [ 2 ] + [5*s - 5 6*s + 18*s - 24] + [------- ----------------] + [6*s - 1 2 ] + [ 6*s - s ]{t} + + """ + _mat = self.sensitivity * self.sys1.doit()._expr_mat + + _resultant_tfm = _to_TFM(_mat, self.var) + + if cancel: + _resultant_tfm = _resultant_tfm.simplify() + + if expand: + _resultant_tfm = _resultant_tfm.expand() + + return _resultant_tfm + + def _eval_rewrite_as_TransferFunctionMatrix(self, sys1, sys2, sign, **kwargs): + return self.doit() + + def __neg__(self): + return MIMOFeedback(-self.sys1, -self.sys2, self.sign) + + +def _to_TFM(mat, var): + """Private method to convert ImmutableMatrix to TransferFunctionMatrix efficiently""" + to_tf = lambda expr: TransferFunction.from_rational_expression(expr, var) + arg = [[to_tf(expr) for expr in row] for row in mat.tolist()] + return TransferFunctionMatrix(arg) + + +class TransferFunctionMatrix(MIMOLinearTimeInvariant): + r""" + A class for representing the MIMO (multiple-input and multiple-output) + generalization of the SISO (single-input and single-output) transfer function. + + It is a matrix of transfer functions (``TransferFunction``, SISO-``Series`` or SISO-``Parallel``). + There is only one argument, ``arg`` which is also the compulsory argument. + ``arg`` is expected to be strictly of the type list of lists + which holds the transfer functions or reducible to transfer functions. + + Parameters + ========== + + arg : Nested ``List`` (strictly). + Users are expected to input a nested list of ``TransferFunction``, ``Series`` + and/or ``Parallel`` objects. + + Examples + ======== + + .. note:: + ``pprint()`` can be used for better visualization of ``TransferFunctionMatrix`` objects. + + >>> from sympy.abc import s, p, a + >>> from sympy import pprint + >>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, Series, Parallel + >>> tf_1 = TransferFunction(s + a, s**2 + s + 1, s) + >>> tf_2 = TransferFunction(p**4 - 3*p + 2, s + p, s) + >>> tf_3 = TransferFunction(3, s + 2, s) + >>> tf_4 = TransferFunction(-a + p, 9*s - 9, s) + >>> tfm_1 = TransferFunctionMatrix([[tf_1], [tf_2], [tf_3]]) + >>> tfm_1 + TransferFunctionMatrix(((TransferFunction(a + s, s**2 + s + 1, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(3, s + 2, s),))) + >>> tfm_1.var + s + >>> tfm_1.num_inputs + 1 + >>> tfm_1.num_outputs + 3 + >>> tfm_1.shape + (3, 1) + >>> tfm_1.args + (((TransferFunction(a + s, s**2 + s + 1, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(3, s + 2, s),)),) + >>> tfm_2 = TransferFunctionMatrix([[tf_1, -tf_3], [tf_2, -tf_1], [tf_3, -tf_2]]) + >>> tfm_2 + TransferFunctionMatrix(((TransferFunction(a + s, s**2 + s + 1, s), TransferFunction(-3, s + 2, s)), (TransferFunction(p**4 - 3*p + 2, p + s, s), TransferFunction(-a - s, s**2 + s + 1, s)), (TransferFunction(3, s + 2, s), TransferFunction(-p**4 + 3*p - 2, p + s, s)))) + >>> pprint(tfm_2, use_unicode=False) # pretty-printing for better visualization + [ a + s -3 ] + [ ---------- ----- ] + [ 2 s + 2 ] + [ s + s + 1 ] + [ ] + [ 4 ] + [p - 3*p + 2 -a - s ] + [------------ ---------- ] + [ p + s 2 ] + [ s + s + 1 ] + [ ] + [ 4 ] + [ 3 - p + 3*p - 2] + [ ----- --------------] + [ s + 2 p + s ]{t} + + TransferFunctionMatrix can be transposed, if user wants to switch the input and output transfer functions + + >>> tfm_2.transpose() + TransferFunctionMatrix(((TransferFunction(a + s, s**2 + s + 1, s), TransferFunction(p**4 - 3*p + 2, p + s, s), TransferFunction(3, s + 2, s)), (TransferFunction(-3, s + 2, s), TransferFunction(-a - s, s**2 + s + 1, s), TransferFunction(-p**4 + 3*p - 2, p + s, s)))) + >>> pprint(_, use_unicode=False) + [ 4 ] + [ a + s p - 3*p + 2 3 ] + [---------- ------------ ----- ] + [ 2 p + s s + 2 ] + [s + s + 1 ] + [ ] + [ 4 ] + [ -3 -a - s - p + 3*p - 2] + [ ----- ---------- --------------] + [ s + 2 2 p + s ] + [ s + s + 1 ]{t} + + >>> tf_5 = TransferFunction(5, s, s) + >>> tf_6 = TransferFunction(5*s, (2 + s**2), s) + >>> tf_7 = TransferFunction(5, (s*(2 + s**2)), s) + >>> tf_8 = TransferFunction(5, 1, s) + >>> tfm_3 = TransferFunctionMatrix([[tf_5, tf_6], [tf_7, tf_8]]) + >>> tfm_3 + TransferFunctionMatrix(((TransferFunction(5, s, s), TransferFunction(5*s, s**2 + 2, s)), (TransferFunction(5, s*(s**2 + 2), s), TransferFunction(5, 1, s)))) + >>> pprint(tfm_3, use_unicode=False) + [ 5 5*s ] + [ - ------] + [ s 2 ] + [ s + 2] + [ ] + [ 5 5 ] + [---------- - ] + [ / 2 \ 1 ] + [s*\s + 2/ ]{t} + >>> tfm_3.var + s + >>> tfm_3.shape + (2, 2) + >>> tfm_3.num_outputs + 2 + >>> tfm_3.num_inputs + 2 + >>> tfm_3.args + (((TransferFunction(5, s, s), TransferFunction(5*s, s**2 + 2, s)), (TransferFunction(5, s*(s**2 + 2), s), TransferFunction(5, 1, s))),) + + To access the ``TransferFunction`` at any index in the ``TransferFunctionMatrix``, use the index notation. + + >>> tfm_3[1, 0] # gives the TransferFunction present at 2nd Row and 1st Col. Similar to that in Matrix classes + TransferFunction(5, s*(s**2 + 2), s) + >>> tfm_3[0, 0] # gives the TransferFunction present at 1st Row and 1st Col. + TransferFunction(5, s, s) + >>> tfm_3[:, 0] # gives the first column + TransferFunctionMatrix(((TransferFunction(5, s, s),), (TransferFunction(5, s*(s**2 + 2), s),))) + >>> pprint(_, use_unicode=False) + [ 5 ] + [ - ] + [ s ] + [ ] + [ 5 ] + [----------] + [ / 2 \] + [s*\s + 2/]{t} + >>> tfm_3[0, :] # gives the first row + TransferFunctionMatrix(((TransferFunction(5, s, s), TransferFunction(5*s, s**2 + 2, s)),)) + >>> pprint(_, use_unicode=False) + [5 5*s ] + [- ------] + [s 2 ] + [ s + 2]{t} + + To negate a transfer function matrix, ``-`` operator can be prepended: + + >>> tfm_4 = TransferFunctionMatrix([[tf_2], [-tf_1], [tf_3]]) + >>> -tfm_4 + TransferFunctionMatrix(((TransferFunction(-p**4 + 3*p - 2, p + s, s),), (TransferFunction(a + s, s**2 + s + 1, s),), (TransferFunction(-3, s + 2, s),))) + >>> tfm_5 = TransferFunctionMatrix([[tf_1, tf_2], [tf_3, -tf_1]]) + >>> -tfm_5 + TransferFunctionMatrix(((TransferFunction(-a - s, s**2 + s + 1, s), TransferFunction(-p**4 + 3*p - 2, p + s, s)), (TransferFunction(-3, s + 2, s), TransferFunction(a + s, s**2 + s + 1, s)))) + + ``subs()`` returns the ``TransferFunctionMatrix`` object with the value substituted in the expression. This will not + mutate your original ``TransferFunctionMatrix``. + + >>> tfm_2.subs(p, 2) # substituting p everywhere in tfm_2 with 2. + TransferFunctionMatrix(((TransferFunction(a + s, s**2 + s + 1, s), TransferFunction(-3, s + 2, s)), (TransferFunction(12, s + 2, s), TransferFunction(-a - s, s**2 + s + 1, s)), (TransferFunction(3, s + 2, s), TransferFunction(-12, s + 2, s)))) + >>> pprint(_, use_unicode=False) + [ a + s -3 ] + [---------- ----- ] + [ 2 s + 2 ] + [s + s + 1 ] + [ ] + [ 12 -a - s ] + [ ----- ----------] + [ s + 2 2 ] + [ s + s + 1] + [ ] + [ 3 -12 ] + [ ----- ----- ] + [ s + 2 s + 2 ]{t} + >>> pprint(tfm_2, use_unicode=False) # State of tfm_2 is unchanged after substitution + [ a + s -3 ] + [ ---------- ----- ] + [ 2 s + 2 ] + [ s + s + 1 ] + [ ] + [ 4 ] + [p - 3*p + 2 -a - s ] + [------------ ---------- ] + [ p + s 2 ] + [ s + s + 1 ] + [ ] + [ 4 ] + [ 3 - p + 3*p - 2] + [ ----- --------------] + [ s + 2 p + s ]{t} + + ``subs()`` also supports multiple substitutions. + + >>> tfm_2.subs({p: 2, a: 1}) # substituting p with 2 and a with 1 + TransferFunctionMatrix(((TransferFunction(s + 1, s**2 + s + 1, s), TransferFunction(-3, s + 2, s)), (TransferFunction(12, s + 2, s), TransferFunction(-s - 1, s**2 + s + 1, s)), (TransferFunction(3, s + 2, s), TransferFunction(-12, s + 2, s)))) + >>> pprint(_, use_unicode=False) + [ s + 1 -3 ] + [---------- ----- ] + [ 2 s + 2 ] + [s + s + 1 ] + [ ] + [ 12 -s - 1 ] + [ ----- ----------] + [ s + 2 2 ] + [ s + s + 1] + [ ] + [ 3 -12 ] + [ ----- ----- ] + [ s + 2 s + 2 ]{t} + + Users can reduce the ``Series`` and ``Parallel`` elements of the matrix to ``TransferFunction`` by using + ``doit()``. + + >>> tfm_6 = TransferFunctionMatrix([[Series(tf_3, tf_4), Parallel(tf_3, tf_4)]]) + >>> tfm_6 + TransferFunctionMatrix(((Series(TransferFunction(3, s + 2, s), TransferFunction(-a + p, 9*s - 9, s)), Parallel(TransferFunction(3, s + 2, s), TransferFunction(-a + p, 9*s - 9, s))),)) + >>> pprint(tfm_6, use_unicode=False) + [-a + p 3 -a + p 3 ] + [-------*----- ------- + -----] + [9*s - 9 s + 2 9*s - 9 s + 2]{t} + >>> tfm_6.doit() + TransferFunctionMatrix(((TransferFunction(-3*a + 3*p, (s + 2)*(9*s - 9), s), TransferFunction(27*s + (-a + p)*(s + 2) - 27, (s + 2)*(9*s - 9), s)),)) + >>> pprint(_, use_unicode=False) + [ -3*a + 3*p 27*s + (-a + p)*(s + 2) - 27] + [----------------- ----------------------------] + [(s + 2)*(9*s - 9) (s + 2)*(9*s - 9) ]{t} + >>> tf_9 = TransferFunction(1, s, s) + >>> tf_10 = TransferFunction(1, s**2, s) + >>> tfm_7 = TransferFunctionMatrix([[Series(tf_9, tf_10), tf_9], [tf_10, Parallel(tf_9, tf_10)]]) + >>> tfm_7 + TransferFunctionMatrix(((Series(TransferFunction(1, s, s), TransferFunction(1, s**2, s)), TransferFunction(1, s, s)), (TransferFunction(1, s**2, s), Parallel(TransferFunction(1, s, s), TransferFunction(1, s**2, s))))) + >>> pprint(tfm_7, use_unicode=False) + [ 1 1 ] + [---- - ] + [ 2 s ] + [s*s ] + [ ] + [ 1 1 1] + [ -- -- + -] + [ 2 2 s] + [ s s ]{t} + >>> tfm_7.doit() + TransferFunctionMatrix(((TransferFunction(1, s**3, s), TransferFunction(1, s, s)), (TransferFunction(1, s**2, s), TransferFunction(s**2 + s, s**3, s)))) + >>> pprint(_, use_unicode=False) + [1 1 ] + [-- - ] + [ 3 s ] + [s ] + [ ] + [ 2 ] + [1 s + s] + [-- ------] + [ 2 3 ] + [s s ]{t} + + Addition, subtraction, and multiplication of transfer function matrices can form + unevaluated ``Series`` or ``Parallel`` objects. + + - For addition and subtraction: + All the transfer function matrices must have the same shape. + + - For multiplication (C = A * B): + The number of inputs of the first transfer function matrix (A) must be equal to the + number of outputs of the second transfer function matrix (B). + + Also, use pretty-printing (``pprint``) to analyse better. + + >>> tfm_8 = TransferFunctionMatrix([[tf_3], [tf_2], [-tf_1]]) + >>> tfm_9 = TransferFunctionMatrix([[-tf_3]]) + >>> tfm_10 = TransferFunctionMatrix([[tf_1], [tf_2], [tf_4]]) + >>> tfm_11 = TransferFunctionMatrix([[tf_4], [-tf_1]]) + >>> tfm_12 = TransferFunctionMatrix([[tf_4, -tf_1, tf_3], [-tf_2, -tf_4, -tf_3]]) + >>> tfm_8 + tfm_10 + MIMOParallel(TransferFunctionMatrix(((TransferFunction(3, s + 2, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(-a - s, s**2 + s + 1, s),))), TransferFunctionMatrix(((TransferFunction(a + s, s**2 + s + 1, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(-a + p, 9*s - 9, s),)))) + >>> pprint(_, use_unicode=False) + [ 3 ] [ a + s ] + [ ----- ] [ ---------- ] + [ s + 2 ] [ 2 ] + [ ] [ s + s + 1 ] + [ 4 ] [ ] + [p - 3*p + 2] [ 4 ] + [------------] + [p - 3*p + 2] + [ p + s ] [------------] + [ ] [ p + s ] + [ -a - s ] [ ] + [ ---------- ] [ -a + p ] + [ 2 ] [ ------- ] + [ s + s + 1 ]{t} [ 9*s - 9 ]{t} + >>> -tfm_10 - tfm_8 + MIMOParallel(TransferFunctionMatrix(((TransferFunction(-a - s, s**2 + s + 1, s),), (TransferFunction(-p**4 + 3*p - 2, p + s, s),), (TransferFunction(a - p, 9*s - 9, s),))), TransferFunctionMatrix(((TransferFunction(-3, s + 2, s),), (TransferFunction(-p**4 + 3*p - 2, p + s, s),), (TransferFunction(a + s, s**2 + s + 1, s),)))) + >>> pprint(_, use_unicode=False) + [ -a - s ] [ -3 ] + [ ---------- ] [ ----- ] + [ 2 ] [ s + 2 ] + [ s + s + 1 ] [ ] + [ ] [ 4 ] + [ 4 ] [- p + 3*p - 2] + [- p + 3*p - 2] + [--------------] + [--------------] [ p + s ] + [ p + s ] [ ] + [ ] [ a + s ] + [ a - p ] [ ---------- ] + [ ------- ] [ 2 ] + [ 9*s - 9 ]{t} [ s + s + 1 ]{t} + >>> tfm_12 * tfm_8 + MIMOSeries(TransferFunctionMatrix(((TransferFunction(3, s + 2, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(-a - s, s**2 + s + 1, s),))), TransferFunctionMatrix(((TransferFunction(-a + p, 9*s - 9, s), TransferFunction(-a - s, s**2 + s + 1, s), TransferFunction(3, s + 2, s)), (TransferFunction(-p**4 + 3*p - 2, p + s, s), TransferFunction(a - p, 9*s - 9, s), TransferFunction(-3, s + 2, s))))) + >>> pprint(_, use_unicode=False) + [ 3 ] + [ ----- ] + [ -a + p -a - s 3 ] [ s + 2 ] + [ ------- ---------- -----] [ ] + [ 9*s - 9 2 s + 2] [ 4 ] + [ s + s + 1 ] [p - 3*p + 2] + [ ] *[------------] + [ 4 ] [ p + s ] + [- p + 3*p - 2 a - p -3 ] [ ] + [-------------- ------- -----] [ -a - s ] + [ p + s 9*s - 9 s + 2]{t} [ ---------- ] + [ 2 ] + [ s + s + 1 ]{t} + >>> tfm_12 * tfm_8 * tfm_9 + MIMOSeries(TransferFunctionMatrix(((TransferFunction(-3, s + 2, s),),)), TransferFunctionMatrix(((TransferFunction(3, s + 2, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(-a - s, s**2 + s + 1, s),))), TransferFunctionMatrix(((TransferFunction(-a + p, 9*s - 9, s), TransferFunction(-a - s, s**2 + s + 1, s), TransferFunction(3, s + 2, s)), (TransferFunction(-p**4 + 3*p - 2, p + s, s), TransferFunction(a - p, 9*s - 9, s), TransferFunction(-3, s + 2, s))))) + >>> pprint(_, use_unicode=False) + [ 3 ] + [ ----- ] + [ -a + p -a - s 3 ] [ s + 2 ] + [ ------- ---------- -----] [ ] + [ 9*s - 9 2 s + 2] [ 4 ] + [ s + s + 1 ] [p - 3*p + 2] [ -3 ] + [ ] *[------------] *[-----] + [ 4 ] [ p + s ] [s + 2]{t} + [- p + 3*p - 2 a - p -3 ] [ ] + [-------------- ------- -----] [ -a - s ] + [ p + s 9*s - 9 s + 2]{t} [ ---------- ] + [ 2 ] + [ s + s + 1 ]{t} + >>> tfm_10 + tfm_8*tfm_9 + MIMOParallel(TransferFunctionMatrix(((TransferFunction(a + s, s**2 + s + 1, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(-a + p, 9*s - 9, s),))), MIMOSeries(TransferFunctionMatrix(((TransferFunction(-3, s + 2, s),),)), TransferFunctionMatrix(((TransferFunction(3, s + 2, s),), (TransferFunction(p**4 - 3*p + 2, p + s, s),), (TransferFunction(-a - s, s**2 + s + 1, s),))))) + >>> pprint(_, use_unicode=False) + [ a + s ] [ 3 ] + [ ---------- ] [ ----- ] + [ 2 ] [ s + 2 ] + [ s + s + 1 ] [ ] + [ ] [ 4 ] + [ 4 ] [p - 3*p + 2] [ -3 ] + [p - 3*p + 2] + [------------] *[-----] + [------------] [ p + s ] [s + 2]{t} + [ p + s ] [ ] + [ ] [ -a - s ] + [ -a + p ] [ ---------- ] + [ ------- ] [ 2 ] + [ 9*s - 9 ]{t} [ s + s + 1 ]{t} + + These unevaluated ``Series`` or ``Parallel`` objects can convert into the + resultant transfer function matrix using ``.doit()`` method or by + ``.rewrite(TransferFunctionMatrix)``. + + >>> (-tfm_8 + tfm_10 + tfm_8*tfm_9).doit() + TransferFunctionMatrix(((TransferFunction((a + s)*(s + 2)**3 - 3*(s + 2)**2*(s**2 + s + 1) - 9*(s + 2)*(s**2 + s + 1), (s + 2)**3*(s**2 + s + 1), s),), (TransferFunction((p + s)*(-3*p**4 + 9*p - 6), (p + s)**2*(s + 2), s),), (TransferFunction((-a + p)*(s + 2)*(s**2 + s + 1)**2 + (a + s)*(s + 2)*(9*s - 9)*(s**2 + s + 1) + (3*a + 3*s)*(9*s - 9)*(s**2 + s + 1), (s + 2)*(9*s - 9)*(s**2 + s + 1)**2, s),))) + >>> (-tfm_12 * -tfm_8 * -tfm_9).rewrite(TransferFunctionMatrix) + TransferFunctionMatrix(((TransferFunction(3*(-3*a + 3*p)*(p + s)*(s + 2)*(s**2 + s + 1)**2 + 3*(-3*a - 3*s)*(p + s)*(s + 2)*(9*s - 9)*(s**2 + s + 1) + 3*(a + s)*(s + 2)**2*(9*s - 9)*(-p**4 + 3*p - 2)*(s**2 + s + 1), (p + s)*(s + 2)**3*(9*s - 9)*(s**2 + s + 1)**2, s),), (TransferFunction(3*(-a + p)*(p + s)*(s + 2)**2*(-p**4 + 3*p - 2)*(s**2 + s + 1) + 3*(3*a + 3*s)*(p + s)**2*(s + 2)*(9*s - 9) + 3*(p + s)*(s + 2)*(9*s - 9)*(-3*p**4 + 9*p - 6)*(s**2 + s + 1), (p + s)**2*(s + 2)**3*(9*s - 9)*(s**2 + s + 1), s),))) + + See Also + ======== + + TransferFunction, MIMOSeries, MIMOParallel, Feedback + + """ + def __new__(cls, arg): + + expr_mat_arg = [] + try: + var = arg[0][0].var + except TypeError: + raise ValueError(filldedent(""" + `arg` param in TransferFunctionMatrix should + strictly be a nested list containing TransferFunction + objects.""")) + for row in arg: + temp = [] + for element in row: + if not isinstance(element, SISOLinearTimeInvariant): + raise TypeError(filldedent(""" + Each element is expected to be of + type `SISOLinearTimeInvariant`.""")) + + if var != element.var: + raise ValueError(filldedent(""" + Conflicting value(s) found for `var`. All TransferFunction + instances in TransferFunctionMatrix should use the same + complex variable in Laplace domain.""")) + + temp.append(element.to_expr()) + expr_mat_arg.append(temp) + + if isinstance(arg, (tuple, list, Tuple)): + # Making nested Tuple (sympy.core.containers.Tuple) from nested list or nested Python tuple + arg = Tuple(*(Tuple(*r, sympify=False) for r in arg), sympify=False) + + obj = super(TransferFunctionMatrix, cls).__new__(cls, arg) + obj._expr_mat = ImmutableMatrix(expr_mat_arg) + return obj + + @classmethod + def from_Matrix(cls, matrix, var): + """ + Creates a new ``TransferFunctionMatrix`` efficiently from a SymPy Matrix of ``Expr`` objects. + + Parameters + ========== + + matrix : ``ImmutableMatrix`` having ``Expr``/``Number`` elements. + var : Symbol + Complex variable of the Laplace transform which will be used by the + all the ``TransferFunction`` objects in the ``TransferFunctionMatrix``. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunctionMatrix + >>> from sympy import Matrix, pprint + >>> M = Matrix([[s, 1/s], [1/(s+1), s]]) + >>> M_tf = TransferFunctionMatrix.from_Matrix(M, s) + >>> pprint(M_tf, use_unicode=False) + [ s 1] + [ - -] + [ 1 s] + [ ] + [ 1 s] + [----- -] + [s + 1 1]{t} + >>> M_tf.elem_poles() + [[[], [0]], [[-1], []]] + >>> M_tf.elem_zeros() + [[[0], []], [[], [0]]] + + """ + return _to_TFM(matrix, var) + + @property + def var(self): + """ + Returns the complex variable used by all the transfer functions or + ``Series``/``Parallel`` objects in a transfer function matrix. + + Examples + ======== + + >>> from sympy.abc import p, s + >>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix, Series, Parallel + >>> G1 = TransferFunction(p**2 + 2*p + 4, p - 6, p) + >>> G2 = TransferFunction(p, 4 - p, p) + >>> G3 = TransferFunction(0, p**4 - 1, p) + >>> G4 = TransferFunction(s + 1, s**2 + s + 1, s) + >>> S1 = Series(G1, G2) + >>> S2 = Series(-G3, Parallel(G2, -G1)) + >>> tfm1 = TransferFunctionMatrix([[G1], [G2], [G3]]) + >>> tfm1.var + p + >>> tfm2 = TransferFunctionMatrix([[-S1, -S2], [S1, S2]]) + >>> tfm2.var + p + >>> tfm3 = TransferFunctionMatrix([[G4]]) + >>> tfm3.var + s + + """ + return self.args[0][0][0].var + + @property + def num_inputs(self): + """ + Returns the number of inputs of the system. + + Examples + ======== + + >>> from sympy.abc import s, p + >>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix + >>> G1 = TransferFunction(s + 3, s**2 - 3, s) + >>> G2 = TransferFunction(4, s**2, s) + >>> G3 = TransferFunction(p**2 + s**2, p - 3, s) + >>> tfm_1 = TransferFunctionMatrix([[G2, -G1, G3], [-G2, -G1, -G3]]) + >>> tfm_1.num_inputs + 3 + + See Also + ======== + + num_outputs + + """ + return self._expr_mat.shape[1] + + @property + def num_outputs(self): + """ + Returns the number of outputs of the system. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunctionMatrix + >>> from sympy import Matrix + >>> M_1 = Matrix([[s], [1/s]]) + >>> TFM = TransferFunctionMatrix.from_Matrix(M_1, s) + >>> print(TFM) + TransferFunctionMatrix(((TransferFunction(s, 1, s),), (TransferFunction(1, s, s),))) + >>> TFM.num_outputs + 2 + + See Also + ======== + + num_inputs + + """ + return self._expr_mat.shape[0] + + @property + def shape(self): + """ + Returns the shape of the transfer function matrix, that is, ``(# of outputs, # of inputs)``. + + Examples + ======== + + >>> from sympy.abc import s, p + >>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix + >>> tf1 = TransferFunction(p**2 - 1, s**4 + s**3 - p, p) + >>> tf2 = TransferFunction(1 - p, p**2 - 3*p + 7, p) + >>> tf3 = TransferFunction(3, 4, p) + >>> tfm1 = TransferFunctionMatrix([[tf1, -tf2]]) + >>> tfm1.shape + (1, 2) + >>> tfm2 = TransferFunctionMatrix([[-tf2, tf3], [tf1, -tf1]]) + >>> tfm2.shape + (2, 2) + + """ + return self._expr_mat.shape + + def __neg__(self): + neg = -self._expr_mat + return _to_TFM(neg, self.var) + + @_check_other_MIMO + def __add__(self, other): + + if not isinstance(other, MIMOParallel): + return MIMOParallel(self, other) + other_arg_list = list(other.args) + return MIMOParallel(self, *other_arg_list) + + @_check_other_MIMO + def __sub__(self, other): + return self + (-other) + + @_check_other_MIMO + def __mul__(self, other): + + if not isinstance(other, MIMOSeries): + return MIMOSeries(other, self) + other_arg_list = list(other.args) + return MIMOSeries(*other_arg_list, self) + + def __getitem__(self, key): + trunc = self._expr_mat.__getitem__(key) + if isinstance(trunc, ImmutableMatrix): + return _to_TFM(trunc, self.var) + return TransferFunction.from_rational_expression(trunc, self.var) + + def transpose(self): + """Returns the transpose of the ``TransferFunctionMatrix`` (switched input and output layers).""" + transposed_mat = self._expr_mat.transpose() + return _to_TFM(transposed_mat, self.var) + + def elem_poles(self): + """ + Returns the poles of each element of the ``TransferFunctionMatrix``. + + .. note:: + Actual poles of a MIMO system are NOT the poles of individual elements. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix + >>> tf_1 = TransferFunction(3, (s + 1), s) + >>> tf_2 = TransferFunction(s + 6, (s + 1)*(s + 2), s) + >>> tf_3 = TransferFunction(s + 3, s**2 + 3*s + 2, s) + >>> tf_4 = TransferFunction(s + 2, s**2 + 5*s - 10, s) + >>> tfm_1 = TransferFunctionMatrix([[tf_1, tf_2], [tf_3, tf_4]]) + >>> tfm_1 + TransferFunctionMatrix(((TransferFunction(3, s + 1, s), TransferFunction(s + 6, (s + 1)*(s + 2), s)), (TransferFunction(s + 3, s**2 + 3*s + 2, s), TransferFunction(s + 2, s**2 + 5*s - 10, s)))) + >>> tfm_1.elem_poles() + [[[-1], [-2, -1]], [[-2, -1], [-5/2 + sqrt(65)/2, -sqrt(65)/2 - 5/2]]] + + See Also + ======== + + elem_zeros + + """ + return [[element.poles() for element in row] for row in self.doit().args[0]] + + def elem_zeros(self): + """ + Returns the zeros of each element of the ``TransferFunctionMatrix``. + + .. note:: + Actual zeros of a MIMO system are NOT the zeros of individual elements. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix + >>> tf_1 = TransferFunction(3, (s + 1), s) + >>> tf_2 = TransferFunction(s + 6, (s + 1)*(s + 2), s) + >>> tf_3 = TransferFunction(s + 3, s**2 + 3*s + 2, s) + >>> tf_4 = TransferFunction(s**2 - 9*s + 20, s**2 + 5*s - 10, s) + >>> tfm_1 = TransferFunctionMatrix([[tf_1, tf_2], [tf_3, tf_4]]) + >>> tfm_1 + TransferFunctionMatrix(((TransferFunction(3, s + 1, s), TransferFunction(s + 6, (s + 1)*(s + 2), s)), (TransferFunction(s + 3, s**2 + 3*s + 2, s), TransferFunction(s**2 - 9*s + 20, s**2 + 5*s - 10, s)))) + >>> tfm_1.elem_zeros() + [[[], [-6]], [[-3], [4, 5]]] + + See Also + ======== + + elem_poles + + """ + return [[element.zeros() for element in row] for row in self.doit().args[0]] + + def eval_frequency(self, other): + """ + Evaluates system response of each transfer function in the ``TransferFunctionMatrix`` at any point in the real or complex plane. + + Examples + ======== + + >>> from sympy.abc import s + >>> from sympy.physics.control.lti import TransferFunction, TransferFunctionMatrix + >>> from sympy import I + >>> tf_1 = TransferFunction(3, (s + 1), s) + >>> tf_2 = TransferFunction(s + 6, (s + 1)*(s + 2), s) + >>> tf_3 = TransferFunction(s + 3, s**2 + 3*s + 2, s) + >>> tf_4 = TransferFunction(s**2 - 9*s + 20, s**2 + 5*s - 10, s) + >>> tfm_1 = TransferFunctionMatrix([[tf_1, tf_2], [tf_3, tf_4]]) + >>> tfm_1 + TransferFunctionMatrix(((TransferFunction(3, s + 1, s), TransferFunction(s + 6, (s + 1)*(s + 2), s)), (TransferFunction(s + 3, s**2 + 3*s + 2, s), TransferFunction(s**2 - 9*s + 20, s**2 + 5*s - 10, s)))) + >>> tfm_1.eval_frequency(2) + Matrix([ + [ 1, 2/3], + [5/12, 3/2]]) + >>> tfm_1.eval_frequency(I*2) + Matrix([ + [ 3/5 - 6*I/5, -I], + [3/20 - 11*I/20, -101/74 + 23*I/74]]) + """ + mat = self._expr_mat.subs(self.var, other) + return mat.expand() + + def _flat(self): + """Returns flattened list of args in TransferFunctionMatrix""" + return [elem for tup in self.args[0] for elem in tup] + + def _eval_evalf(self, prec): + """Calls evalf() on each transfer function in the transfer function matrix""" + dps = prec_to_dps(prec) + mat = self._expr_mat.applyfunc(lambda a: a.evalf(n=dps)) + return _to_TFM(mat, self.var) + + def _eval_simplify(self, **kwargs): + """Simplifies the transfer function matrix""" + simp_mat = self._expr_mat.applyfunc(lambda a: cancel(a, expand=False)) + return _to_TFM(simp_mat, self.var) + + def expand(self, **hints): + """Expands the transfer function matrix""" + expand_mat = self._expr_mat.expand(**hints) + return _to_TFM(expand_mat, self.var) + +class StateSpace(LinearTimeInvariant): + r""" + State space model (ssm) of a linear, time invariant control system. + + Represents the standard state-space model with A, B, C, D as state-space matrices. + This makes the linear control system: + (1) x'(t) = A * x(t) + B * u(t); x in R^n , u in R^k + (2) y(t) = C * x(t) + D * u(t); y in R^m + where u(t) is any input signal, y(t) the corresponding output, and x(t) the system's state. + + Parameters + ========== + + A : Matrix + The State matrix of the state space model. + B : Matrix + The Input-to-State matrix of the state space model. + C : Matrix + The State-to-Output matrix of the state space model. + D : Matrix + The Feedthrough matrix of the state space model. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + + The easiest way to create a StateSpaceModel is via four matrices: + + >>> A = Matrix([[1, 2], [1, 0]]) + >>> B = Matrix([1, 1]) + >>> C = Matrix([[0, 1]]) + >>> D = Matrix([0]) + >>> StateSpace(A, B, C, D) + StateSpace(Matrix([ + [1, 2], + [1, 0]]), Matrix([ + [1], + [1]]), Matrix([[0, 1]]), Matrix([[0]])) + + + One can use less matrices. The rest will be filled with a minimum of zeros: + + >>> StateSpace(A, B) + StateSpace(Matrix([ + [1, 2], + [1, 0]]), Matrix([ + [1], + [1]]), Matrix([[0, 0]]), Matrix([[0]])) + + + See Also + ======== + + TransferFunction, TransferFunctionMatrix + + References + ========== + .. [1] https://en.wikipedia.org/wiki/State-space_representation + .. [2] https://in.mathworks.com/help/control/ref/ss.html + + """ + def __new__(cls, A=None, B=None, C=None, D=None): + if A is None: + A = zeros(1) + if B is None: + B = zeros(A.rows, 1) + if C is None: + C = zeros(1, A.cols) + if D is None: + D = zeros(C.rows, B.cols) + + A = _sympify(A) + B = _sympify(B) + C = _sympify(C) + D = _sympify(D) + + if (isinstance(A, ImmutableDenseMatrix) and isinstance(B, ImmutableDenseMatrix) and + isinstance(C, ImmutableDenseMatrix) and isinstance(D, ImmutableDenseMatrix)): + # Check State Matrix is square + if A.rows != A.cols: + raise ShapeError("Matrix A must be a square matrix.") + + # Check State and Input matrices have same rows + if A.rows != B.rows: + raise ShapeError("Matrices A and B must have the same number of rows.") + + # Check Ouput and Feedthrough matrices have same rows + if C.rows != D.rows: + raise ShapeError("Matrices C and D must have the same number of rows.") + + # Check State and Ouput matrices have same columns + if A.cols != C.cols: + raise ShapeError("Matrices A and C must have the same number of columns.") + + # Check Input and Feedthrough matrices have same columns + if B.cols != D.cols: + raise ShapeError("Matrices B and D must have the same number of columns.") + + obj = super(StateSpace, cls).__new__(cls, A, B, C, D) + obj._A = A + obj._B = B + obj._C = C + obj._D = D + + # Determine if the system is SISO or MIMO + num_outputs = D.rows + num_inputs = D.cols + if num_inputs == 1 and num_outputs == 1: + obj._is_SISO = True + obj._clstype = SISOLinearTimeInvariant + else: + obj._is_SISO = False + obj._clstype = MIMOLinearTimeInvariant + + return obj + + else: + raise TypeError("A, B, C and D inputs must all be sympy Matrices.") + + @property + def state_matrix(self): + """ + Returns the state matrix of the model. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[1, 2], [1, 0]]) + >>> B = Matrix([1, 1]) + >>> C = Matrix([[0, 1]]) + >>> D = Matrix([0]) + >>> ss = StateSpace(A, B, C, D) + >>> ss.state_matrix + Matrix([ + [1, 2], + [1, 0]]) + + """ + return self._A + + @property + def input_matrix(self): + """ + Returns the input matrix of the model. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[1, 2], [1, 0]]) + >>> B = Matrix([1, 1]) + >>> C = Matrix([[0, 1]]) + >>> D = Matrix([0]) + >>> ss = StateSpace(A, B, C, D) + >>> ss.input_matrix + Matrix([ + [1], + [1]]) + + """ + return self._B + + @property + def output_matrix(self): + """ + Returns the output matrix of the model. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[1, 2], [1, 0]]) + >>> B = Matrix([1, 1]) + >>> C = Matrix([[0, 1]]) + >>> D = Matrix([0]) + >>> ss = StateSpace(A, B, C, D) + >>> ss.output_matrix + Matrix([[0, 1]]) + + """ + return self._C + + @property + def feedforward_matrix(self): + """ + Returns the feedforward matrix of the model. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[1, 2], [1, 0]]) + >>> B = Matrix([1, 1]) + >>> C = Matrix([[0, 1]]) + >>> D = Matrix([0]) + >>> ss = StateSpace(A, B, C, D) + >>> ss.feedforward_matrix + Matrix([[0]]) + + """ + return self._D + + @property + def num_states(self): + """ + Returns the number of states of the model. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[1, 2], [1, 0]]) + >>> B = Matrix([1, 1]) + >>> C = Matrix([[0, 1]]) + >>> D = Matrix([0]) + >>> ss = StateSpace(A, B, C, D) + >>> ss.num_states + 2 + + """ + return self._A.rows + + @property + def num_inputs(self): + """ + Returns the number of inputs of the model. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[1, 2], [1, 0]]) + >>> B = Matrix([1, 1]) + >>> C = Matrix([[0, 1]]) + >>> D = Matrix([0]) + >>> ss = StateSpace(A, B, C, D) + >>> ss.num_inputs + 1 + + """ + return self._D.cols + + @property + def num_outputs(self): + """ + Returns the number of outputs of the model. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[1, 2], [1, 0]]) + >>> B = Matrix([1, 1]) + >>> C = Matrix([[0, 1]]) + >>> D = Matrix([0]) + >>> ss = StateSpace(A, B, C, D) + >>> ss.num_outputs + 1 + + """ + return self._D.rows + + def _eval_evalf(self, prec): + """ + Returns state space model where numerical expressions are evaluated into floating point numbers. + """ + dps = prec_to_dps(prec) + return StateSpace( + self._A.evalf(n = dps), + self._B.evalf(n = dps), + self._C.evalf(n = dps), + self._D.evalf(n = dps)) + + def _eval_rewrite_as_TransferFunction(self, *args): + """ + Returns the equivalent Transfer Function of the state space model. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import TransferFunction, StateSpace + >>> A = Matrix([[-5, -1], [3, -1]]) + >>> B = Matrix([2, 5]) + >>> C = Matrix([[1, 2]]) + >>> D = Matrix([0]) + >>> ss = StateSpace(A, B, C, D) + >>> ss.rewrite(TransferFunction) + [[TransferFunction(12*s + 59, s**2 + 6*s + 8, s)]] + + """ + s = Symbol('s') + n = self._A.shape[0] + I = eye(n) + G = self._C*(s*I - self._A).solve(self._B) + self._D + G = G.simplify() + to_tf = lambda expr: TransferFunction.from_rational_expression(expr, s) + tf_mat = [[to_tf(expr) for expr in sublist] for sublist in G.tolist()] + return tf_mat + + def __add__(self, other): + """ + Add two State Space systems (parallel connection). + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A1 = Matrix([[1]]) + >>> B1 = Matrix([[2]]) + >>> C1 = Matrix([[-1]]) + >>> D1 = Matrix([[-2]]) + >>> A2 = Matrix([[-1]]) + >>> B2 = Matrix([[-2]]) + >>> C2 = Matrix([[1]]) + >>> D2 = Matrix([[2]]) + >>> ss1 = StateSpace(A1, B1, C1, D1) + >>> ss2 = StateSpace(A2, B2, C2, D2) + >>> ss1 + ss2 + StateSpace(Matrix([ + [1, 0], + [0, -1]]), Matrix([ + [ 2], + [-2]]), Matrix([[-1, 1]]), Matrix([[0]])) + + """ + # Check for scalars + if isinstance(other, (int, float, complex, Symbol)): + A = self._A + B = self._B + C = self._C + D = self._D.applyfunc(lambda element: element + other) + + else: + # Check nature of system + if not isinstance(other, StateSpace): + raise ValueError("Addition is only supported for 2 State Space models.") + # Check dimensions of system + elif ((self.num_inputs != other.num_inputs) or (self.num_outputs != other.num_outputs)): + raise ShapeError("Systems with incompatible inputs and outputs cannot be added.") + + m1 = (self._A).row_join(zeros(self._A.shape[0], other._A.shape[-1])) + m2 = zeros(other._A.shape[0], self._A.shape[-1]).row_join(other._A) + + A = m1.col_join(m2) + B = self._B.col_join(other._B) + C = self._C.row_join(other._C) + D = self._D + other._D + + return StateSpace(A, B, C, D) + + def __radd__(self, other): + """ + Right add two State Space systems. + + Examples + ======== + + >>> from sympy.physics.control import StateSpace + >>> s = StateSpace() + >>> 5 + s + StateSpace(Matrix([[0]]), Matrix([[0]]), Matrix([[0]]), Matrix([[5]])) + + """ + return self + other + + def __sub__(self, other): + """ + Subtract two State Space systems. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A1 = Matrix([[1]]) + >>> B1 = Matrix([[2]]) + >>> C1 = Matrix([[-1]]) + >>> D1 = Matrix([[-2]]) + >>> A2 = Matrix([[-1]]) + >>> B2 = Matrix([[-2]]) + >>> C2 = Matrix([[1]]) + >>> D2 = Matrix([[2]]) + >>> ss1 = StateSpace(A1, B1, C1, D1) + >>> ss2 = StateSpace(A2, B2, C2, D2) + >>> ss1 - ss2 + StateSpace(Matrix([ + [1, 0], + [0, -1]]), Matrix([ + [ 2], + [-2]]), Matrix([[-1, -1]]), Matrix([[-4]])) + + """ + return self + (-other) + + def __rsub__(self, other): + """ + Right subtract two tate Space systems. + + Examples + ======== + + >>> from sympy.physics.control import StateSpace + >>> s = StateSpace() + >>> 5 - s + StateSpace(Matrix([[0]]), Matrix([[0]]), Matrix([[0]]), Matrix([[5]])) + + """ + return other + (-self) + + def __neg__(self): + """ + Returns the negation of the state space model. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[-5, -1], [3, -1]]) + >>> B = Matrix([2, 5]) + >>> C = Matrix([[1, 2]]) + >>> D = Matrix([0]) + >>> ss = StateSpace(A, B, C, D) + >>> -ss + StateSpace(Matrix([ + [-5, -1], + [ 3, -1]]), Matrix([ + [2], + [5]]), Matrix([[-1, -2]]), Matrix([[0]])) + + """ + return StateSpace(self._A, self._B, -self._C, -self._D) + + def __mul__(self, other): + """ + Multiplication of two State Space systems (serial connection). + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[-5, -1], [3, -1]]) + >>> B = Matrix([2, 5]) + >>> C = Matrix([[1, 2]]) + >>> D = Matrix([0]) + >>> ss = StateSpace(A, B, C, D) + >>> ss*5 + StateSpace(Matrix([ + [-5, -1], + [ 3, -1]]), Matrix([ + [2], + [5]]), Matrix([[5, 10]]), Matrix([[0]])) + + """ + # Check for scalars + if isinstance(other, (int, float, complex, Symbol)): + A = self._A + B = self._B + C = self._C.applyfunc(lambda element: element*other) + D = self._D.applyfunc(lambda element: element*other) + + else: + # Check nature of system + if not isinstance(other, StateSpace): + raise ValueError("Multiplication is only supported for 2 State Space models.") + # Check dimensions of system + elif self.num_inputs != other.num_outputs: + raise ShapeError("Systems with incompatible inputs and outputs cannot be multiplied.") + + m1 = (other._A).row_join(zeros(other._A.shape[0], self._A.shape[1])) + m2 = (self._B * other._C).row_join(self._A) + + A = m1.col_join(m2) + B = (other._B).col_join(self._B * other._D) + C = (self._D * other._C).row_join(self._C) + D = self._D * other._D + + return StateSpace(A, B, C, D) + + def __rmul__(self, other): + """ + Right multiply two tate Space systems. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[-5, -1], [3, -1]]) + >>> B = Matrix([2, 5]) + >>> C = Matrix([[1, 2]]) + >>> D = Matrix([0]) + >>> ss = StateSpace(A, B, C, D) + >>> 5*ss + StateSpace(Matrix([ + [-5, -1], + [ 3, -1]]), Matrix([ + [10], + [25]]), Matrix([[1, 2]]), Matrix([[0]])) + + """ + if isinstance(other, (int, float, complex, Symbol)): + A = self._A + C = self._C + B = self._B.applyfunc(lambda element: element*other) + D = self._D.applyfunc(lambda element: element*other) + return StateSpace(A, B, C, D) + else: + return self*other + + def __repr__(self): + A_str = self._A.__repr__() + B_str = self._B.__repr__() + C_str = self._C.__repr__() + D_str = self._D.__repr__() + + return f"StateSpace(\n{A_str},\n\n{B_str},\n\n{C_str},\n\n{D_str})" + + + def append(self, other): + """ + Returns the first model appended with the second model. The order is preserved. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A1 = Matrix([[1]]) + >>> B1 = Matrix([[2]]) + >>> C1 = Matrix([[-1]]) + >>> D1 = Matrix([[-2]]) + >>> A2 = Matrix([[-1]]) + >>> B2 = Matrix([[-2]]) + >>> C2 = Matrix([[1]]) + >>> D2 = Matrix([[2]]) + >>> ss1 = StateSpace(A1, B1, C1, D1) + >>> ss2 = StateSpace(A2, B2, C2, D2) + >>> ss1.append(ss2) + StateSpace(Matrix([ + [1, 0], + [0, -1]]), Matrix([ + [2, 0], + [0, -2]]), Matrix([ + [-1, 0], + [ 0, 1]]), Matrix([ + [-2, 0], + [ 0, 2]])) + + """ + n = self.num_states + other.num_states + m = self.num_inputs + other.num_inputs + p = self.num_outputs + other.num_outputs + + A = zeros(n, n) + B = zeros(n, m) + C = zeros(p, n) + D = zeros(p, m) + + A[:self.num_states, :self.num_states] = self._A + A[self.num_states:, self.num_states:] = other._A + B[:self.num_states, :self.num_inputs] = self._B + B[self.num_states:, self.num_inputs:] = other._B + C[:self.num_outputs, :self.num_states] = self._C + C[self.num_outputs:, self.num_states:] = other._C + D[:self.num_outputs, :self.num_inputs] = self._D + D[self.num_outputs:, self.num_inputs:] = other._D + return StateSpace(A, B, C, D) + + def observability_matrix(self): + """ + Returns the observability matrix of the state space model: + [C, C * A^1, C * A^2, .. , C * A^(n-1)]; A in R^(n x n), C in R^(m x k) + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[-1.5, -2], [1, 0]]) + >>> B = Matrix([0.5, 0]) + >>> C = Matrix([[0, 1]]) + >>> D = Matrix([1]) + >>> ss = StateSpace(A, B, C, D) + >>> ob = ss.observability_matrix() + >>> ob + Matrix([ + [0, 1], + [1, 0]]) + + References + ========== + .. [1] https://in.mathworks.com/help/control/ref/statespacemodel.obsv.html + + """ + n = self.num_states + ob = self._C + for i in range(1,n): + ob = ob.col_join(self._C * self._A**i) + + return ob + + def observable_subspace(self): + """ + Returns the observable subspace of the state space model. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[-1.5, -2], [1, 0]]) + >>> B = Matrix([0.5, 0]) + >>> C = Matrix([[0, 1]]) + >>> D = Matrix([1]) + >>> ss = StateSpace(A, B, C, D) + >>> ob_subspace = ss.observable_subspace() + >>> ob_subspace + [Matrix([ + [0], + [1]]), Matrix([ + [1], + [0]])] + + """ + return self.observability_matrix().columnspace() + + def is_observable(self): + """ + Returns if the state space model is observable. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[-1.5, -2], [1, 0]]) + >>> B = Matrix([0.5, 0]) + >>> C = Matrix([[0, 1]]) + >>> D = Matrix([1]) + >>> ss = StateSpace(A, B, C, D) + >>> ss.is_observable() + True + + """ + return self.observability_matrix().rank() == self.num_states + + def controllability_matrix(self): + """ + Returns the controllability matrix of the system: + [B, A * B, A^2 * B, .. , A^(n-1) * B]; A in R^(n x n), B in R^(n x m) + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[-1.5, -2], [1, 0]]) + >>> B = Matrix([0.5, 0]) + >>> C = Matrix([[0, 1]]) + >>> D = Matrix([1]) + >>> ss = StateSpace(A, B, C, D) + >>> ss.controllability_matrix() + Matrix([ + [0.5, -0.75], + [ 0, 0.5]]) + + References + ========== + .. [1] https://in.mathworks.com/help/control/ref/statespacemodel.ctrb.html + + """ + co = self._B + n = self._A.shape[0] + for i in range(1, n): + co = co.row_join(((self._A)**i) * self._B) + + return co + + def controllable_subspace(self): + """ + Returns the controllable subspace of the state space model. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[-1.5, -2], [1, 0]]) + >>> B = Matrix([0.5, 0]) + >>> C = Matrix([[0, 1]]) + >>> D = Matrix([1]) + >>> ss = StateSpace(A, B, C, D) + >>> co_subspace = ss.controllable_subspace() + >>> co_subspace + [Matrix([ + [0.5], + [ 0]]), Matrix([ + [-0.75], + [ 0.5]])] + + """ + return self.controllability_matrix().columnspace() + + def is_controllable(self): + """ + Returns if the state space model is controllable. + + Examples + ======== + + >>> from sympy import Matrix + >>> from sympy.physics.control import StateSpace + >>> A = Matrix([[-1.5, -2], [1, 0]]) + >>> B = Matrix([0.5, 0]) + >>> C = Matrix([[0, 1]]) + >>> D = Matrix([1]) + >>> ss = StateSpace(A, B, C, D) + >>> ss.is_controllable() + True + + """ + return self.controllability_matrix().rank() == self.num_states diff --git a/lib/python3.12/site-packages/sympy/physics/control/tests/__init__.py b/lib/python3.12/site-packages/sympy/physics/control/tests/__init__.py new file mode 100644 index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 diff --git a/lib/python3.12/site-packages/sympy/physics/control/tests/__pycache__/__init__.cpython-312.pyc b/lib/python3.12/site-packages/sympy/physics/control/tests/__pycache__/__init__.cpython-312.pyc new file mode 100644 index 0000000000000000000000000000000000000000..5266dd00f945bcb2e5fabcba0ae82d22d5a5d0a4 Binary files /dev/null and b/lib/python3.12/site-packages/sympy/physics/control/tests/__pycache__/__init__.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/control/tests/__pycache__/test_control_plots.cpython-312.pyc b/lib/python3.12/site-packages/sympy/physics/control/tests/__pycache__/test_control_plots.cpython-312.pyc new file mode 100644 index 0000000000000000000000000000000000000000..28fbd05088fabe91e727a8a729bf386afce8a8cd Binary files /dev/null and b/lib/python3.12/site-packages/sympy/physics/control/tests/__pycache__/test_control_plots.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/control/tests/test_control_plots.py b/lib/python3.12/site-packages/sympy/physics/control/tests/test_control_plots.py new file mode 100644 index 0000000000000000000000000000000000000000..673fcee6cfdbde67ab691d2fbe2f8c36d86c9443 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/control/tests/test_control_plots.py @@ -0,0 +1,299 @@ +from math import isclose +from sympy.core.numbers import I +from sympy.core.symbol import Dummy +from sympy.functions.elementary.complexes import (Abs, arg) +from sympy.functions.elementary.exponential import log +from sympy.abc import s, p, a +from sympy.external import import_module +from sympy.physics.control.control_plots import \ + (pole_zero_numerical_data, pole_zero_plot, step_response_numerical_data, + step_response_plot, impulse_response_numerical_data, + impulse_response_plot, ramp_response_numerical_data, + ramp_response_plot, bode_magnitude_numerical_data, + bode_phase_numerical_data, bode_plot) +from sympy.physics.control.lti import (TransferFunction, + Series, Parallel, TransferFunctionMatrix) +from sympy.testing.pytest import raises, skip + +matplotlib = import_module( + 'matplotlib', import_kwargs={'fromlist': ['pyplot']}, + catch=(RuntimeError,)) + +numpy = import_module('numpy') + +tf1 = TransferFunction(1, p**2 + 0.5*p + 2, p) +tf2 = TransferFunction(p, 6*p**2 + 3*p + 1, p) +tf3 = TransferFunction(p, p**3 - 1, p) +tf4 = TransferFunction(10, p**3, p) +tf5 = TransferFunction(5, s**2 + 2*s + 10, s) +tf6 = TransferFunction(1, 1, s) +tf7 = TransferFunction(4*s*3 + 9*s**2 + 0.1*s + 11, 8*s**6 + 9*s**4 + 11, s) +tf8 = TransferFunction(5, s**2 + (2+I)*s + 10, s) + +ser1 = Series(tf4, TransferFunction(1, p - 5, p)) +ser2 = Series(tf3, TransferFunction(p, p + 2, p)) + +par1 = Parallel(tf1, tf2) + + +def _to_tuple(a, b): + return tuple(a), tuple(b) + +def _trim_tuple(a, b): + a, b = _to_tuple(a, b) + return tuple(a[0: 2] + a[len(a)//2 : len(a)//2 + 1] + a[-2:]), \ + tuple(b[0: 2] + b[len(b)//2 : len(b)//2 + 1] + b[-2:]) + +def y_coordinate_equality(plot_data_func, evalf_func, system): + """Checks whether the y-coordinate value of the plotted + data point is equal to the value of the function at a + particular x.""" + x, y = plot_data_func(system) + x, y = _trim_tuple(x, y) + y_exp = tuple(evalf_func(system, x_i) for x_i in x) + return all(Abs(y_exp_i - y_i) < 1e-8 for y_exp_i, y_i in zip(y_exp, y)) + + +def test_errors(): + if not matplotlib: + skip("Matplotlib not the default backend") + + # Invalid `system` check + tfm = TransferFunctionMatrix([[tf6, tf5], [tf5, tf6]]) + expr = 1/(s**2 - 1) + raises(NotImplementedError, lambda: pole_zero_plot(tfm)) + raises(NotImplementedError, lambda: pole_zero_numerical_data(expr)) + raises(NotImplementedError, lambda: impulse_response_plot(expr)) + raises(NotImplementedError, lambda: impulse_response_numerical_data(tfm)) + raises(NotImplementedError, lambda: step_response_plot(tfm)) + raises(NotImplementedError, lambda: step_response_numerical_data(expr)) + raises(NotImplementedError, lambda: ramp_response_plot(expr)) + raises(NotImplementedError, lambda: ramp_response_numerical_data(tfm)) + raises(NotImplementedError, lambda: bode_plot(tfm)) + + # More than 1 variables + tf_a = TransferFunction(a, s + 1, s) + raises(ValueError, lambda: pole_zero_plot(tf_a)) + raises(ValueError, lambda: pole_zero_numerical_data(tf_a)) + raises(ValueError, lambda: impulse_response_plot(tf_a)) + raises(ValueError, lambda: impulse_response_numerical_data(tf_a)) + raises(ValueError, lambda: step_response_plot(tf_a)) + raises(ValueError, lambda: step_response_numerical_data(tf_a)) + raises(ValueError, lambda: ramp_response_plot(tf_a)) + raises(ValueError, lambda: ramp_response_numerical_data(tf_a)) + raises(ValueError, lambda: bode_plot(tf_a)) + + # lower_limit > 0 for response plots + raises(ValueError, lambda: impulse_response_plot(tf1, lower_limit=-1)) + raises(ValueError, lambda: step_response_plot(tf1, lower_limit=-0.1)) + raises(ValueError, lambda: ramp_response_plot(tf1, lower_limit=-4/3)) + + # slope in ramp_response_plot() is negative + raises(ValueError, lambda: ramp_response_plot(tf1, slope=-0.1)) + + # incorrect frequency or phase unit + raises(ValueError, lambda: bode_plot(tf1,freq_unit = 'hz')) + raises(ValueError, lambda: bode_plot(tf1,phase_unit = 'degree')) + + +def test_pole_zero(): + if not numpy: + skip("NumPy is required for this test") + + def pz_tester(sys, expected_value): + z, p = pole_zero_numerical_data(sys) + z_check = numpy.allclose(z, expected_value[0]) + p_check = numpy.allclose(p, expected_value[1]) + return p_check and z_check + + exp1 = [[], [-0.24999999999999994+1.3919410907075054j, -0.24999999999999994-1.3919410907075054j]] + exp2 = [[0.0], [-0.25+0.3227486121839514j, -0.25-0.3227486121839514j]] + exp3 = [[0.0], [-0.5000000000000004+0.8660254037844395j, + -0.5000000000000004-0.8660254037844395j, 0.9999999999999998+0j]] + exp4 = [[], [5.0, 0.0, 0.0, 0.0]] + exp5 = [[-5.645751311064592, -0.5000000000000008, -0.3542486889354093], + [-0.24999999999999986+1.3919410907075052j, + -0.24999999999999986-1.3919410907075052j, -0.2499999999999998+0.32274861218395134j, + -0.2499999999999998-0.32274861218395134j]] + exp6 = [[], [-1.1641600331447917-3.545808351896439j, + -0.8358399668552097+2.5458083518964383j]] + + assert pz_tester(tf1, exp1) + assert pz_tester(tf2, exp2) + assert pz_tester(tf3, exp3) + assert pz_tester(ser1, exp4) + assert pz_tester(par1, exp5) + assert pz_tester(tf8, exp6) + + +def test_bode(): + if not numpy: + skip("NumPy is required for this test") + + def bode_phase_evalf(system, point): + expr = system.to_expr() + _w = Dummy("w", real=True) + w_expr = expr.subs({system.var: I*_w}) + return arg(w_expr).subs({_w: point}).evalf() + + def bode_mag_evalf(system, point): + expr = system.to_expr() + _w = Dummy("w", real=True) + w_expr = expr.subs({system.var: I*_w}) + return 20*log(Abs(w_expr), 10).subs({_w: point}).evalf() + + def test_bode_data(sys): + return y_coordinate_equality(bode_magnitude_numerical_data, bode_mag_evalf, sys) \ + and y_coordinate_equality(bode_phase_numerical_data, bode_phase_evalf, sys) + + assert test_bode_data(tf1) + assert test_bode_data(tf2) + assert test_bode_data(tf3) + assert test_bode_data(tf4) + assert test_bode_data(tf5) + + +def check_point_accuracy(a, b): + return all(isclose(*_, rel_tol=1e-1, abs_tol=1e-6 + ) for _ in zip(a, b)) + + +def test_impulse_response(): + if not numpy: + skip("NumPy is required for this test") + + def impulse_res_tester(sys, expected_value): + x, y = _to_tuple(*impulse_response_numerical_data(sys, + adaptive=False, n=10)) + x_check = check_point_accuracy(x, expected_value[0]) + y_check = check_point_accuracy(y, expected_value[1]) + return x_check and y_check + + exp1 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, + 5.555555555555555, 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), + (0.0, 0.544019738507865, 0.01993849743234938, -0.31140243360893216, -0.022852779906491996, 0.1778306498155759, + 0.01962941084328499, -0.1013115194573652, -0.014975541213105696, 0.0575789724730714)) + exp2 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, 5.555555555555555, + 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), (0.1666666675, 0.08389223412935855, + 0.02338051973475047, -0.014966807776379383, -0.034645954223054234, -0.040560075735512804, + -0.037658628907103885, -0.030149507719590022, -0.021162090730736834, -0.012721292737437523)) + exp3 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, 5.555555555555555, + 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), (4.369893391586999e-09, 1.1750333000630964, + 3.2922404058312473, 9.432290008148343, 28.37098083007151, 86.18577464367974, 261.90356653762115, + 795.6538758627842, 2416.9920942096983, 7342.159505206647)) + exp4 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, 5.555555555555555, + 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), (0.0, 6.17283950617284, 24.69135802469136, + 55.555555555555564, 98.76543209876544, 154.320987654321, 222.22222222222226, 302.46913580246917, + 395.0617283950618, 500.0)) + exp5 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, 5.555555555555555, + 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), (0.0, -0.10455606138085417, + 0.06757671513476461, -0.03234567568833768, 0.013582514927757873, -0.005273419510705473, + 0.0019364083003354075, -0.000680070134067832, 0.00022969845960406913, -7.476094359583917e-05)) + exp6 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, + 5.555555555555555, 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), + (-6.016699583000218e-09, 0.35039802056107394, 3.3728423827689884, 12.119846079276684, + 25.86101014293389, 29.352480635282088, -30.49475907497664, -273.8717189554019, -863.2381702029659, + -1747.0262164682233)) + exp7 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, + 4.444444444444445, 5.555555555555555, 6.666666666666667, 7.777777777777779, + 8.88888888888889, 10.0), (0.0, 18.934638095560974, 5346.93244680907, 1384609.8718249386, + 358161126.65801865, 92645770015.70108, 23964739753087.42, 6198974342083139.0, 1.603492601616059e+18, + 4.147764422869658e+20)) + + assert impulse_res_tester(tf1, exp1) + assert impulse_res_tester(tf2, exp2) + assert impulse_res_tester(tf3, exp3) + assert impulse_res_tester(tf4, exp4) + assert impulse_res_tester(tf5, exp5) + assert impulse_res_tester(tf7, exp6) + assert impulse_res_tester(ser1, exp7) + + +def test_step_response(): + if not numpy: + skip("NumPy is required for this test") + + def step_res_tester(sys, expected_value): + x, y = _to_tuple(*step_response_numerical_data(sys, + adaptive=False, n=10)) + x_check = check_point_accuracy(x, expected_value[0]) + y_check = check_point_accuracy(y, expected_value[1]) + return x_check and y_check + + exp1 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, + 5.555555555555555, 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), + (-1.9193285738516863e-08, 0.42283495488246126, 0.7840485977945262, 0.5546841805655717, + 0.33903033806932087, 0.4627251747410237, 0.5909907598988051, 0.5247213989553071, + 0.4486997874319281, 0.4839358435839171)) + exp2 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, + 5.555555555555555, 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), + (0.0, 0.13728409095645816, 0.19474559355325086, 0.1974909129243011, 0.16841657696573073, + 0.12559777736159378, 0.08153828016664713, 0.04360471317348958, 0.015072994568868221, + -0.003636420058445484)) + exp3 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, + 5.555555555555555, 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), + (0.0, 0.6314542141914303, 2.9356520038101035, 9.37731009663807, 28.452300356688376, + 86.25721933273988, 261.9236645044672, 795.6435410577224, 2416.9786984578764, 7342.154119725917)) + exp4 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, + 5.555555555555555, 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), + (0.0, 2.286236899862826, 18.28989519890261, 61.72839629629631, 146.31916159122088, 285.7796124828532, + 493.8271703703705, 784.1792566529494, 1170.553292729767, 1666.6667)) + exp5 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, + 5.555555555555555, 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), + (-3.999999997894577e-09, 0.6720357068882895, 0.4429938256137113, 0.5182010838004518, + 0.4944139147159695, 0.5016379853883338, 0.4995466896527733, 0.5001154784851325, + 0.49997448824584123, 0.5000039745919259)) + exp6 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, + 5.555555555555555, 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), + (-1.5433688493882158e-09, 0.3428705539937336, 1.1253619102202777, 3.1849962651016517, + 9.47532757182671, 28.727231099148135, 87.29426924860557, 265.2138681048606, 805.6636260007757, + 2447.387582370878)) + + assert step_res_tester(tf1, exp1) + assert step_res_tester(tf2, exp2) + assert step_res_tester(tf3, exp3) + assert step_res_tester(tf4, exp4) + assert step_res_tester(tf5, exp5) + assert step_res_tester(ser2, exp6) + + +def test_ramp_response(): + if not numpy: + skip("NumPy is required for this test") + + def ramp_res_tester(sys, num_points, expected_value, slope=1): + x, y = _to_tuple(*ramp_response_numerical_data(sys, + slope=slope, adaptive=False, n=num_points)) + x_check = check_point_accuracy(x, expected_value[0]) + y_check = check_point_accuracy(y, expected_value[1]) + return x_check and y_check + + exp1 = ((0.0, 2.0, 4.0, 6.0, 8.0, 10.0), (0.0, 0.7324667795033895, 1.9909720978650398, + 2.7956587704217783, 3.9224897567931514, 4.85022655284895)) + exp2 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, + 5.555555555555555, 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), + (2.4360213402019326e-08, 0.10175320182493253, 0.33057612497658406, 0.5967937263298935, + 0.8431511866718248, 1.0398805391471613, 1.1776043125035738, 1.2600994825747305, 1.2981042689274653, + 1.304684417610106)) + exp3 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, 5.555555555555555, + 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), (-3.9329040468771836e-08, + 0.34686634635794555, 2.9998828170537903, 12.33303690737476, 40.993913948137795, 127.84145222317912, + 391.41713691996, 1192.0006858708389, 3623.9808672503405, 11011.728034546572)) + exp4 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, 5.555555555555555, + 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), (0.0, 1.9051973784484078, 30.483158055174524, + 154.32098765432104, 487.7305288827924, 1190.7483615302544, 2469.1358024691367, 4574.3789056546275, + 7803.688462124678, 12500.0)) + exp5 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, 5.555555555555555, + 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), (0.0, 3.8844361856975635, 9.141792069209865, + 14.096349157657231, 19.09783068994694, 24.10179770390321, 29.09907319114121, 34.10040420185154, + 39.09983919254265, 44.10006013058409)) + exp6 = ((0.0, 1.1111111111111112, 2.2222222222222223, 3.3333333333333335, 4.444444444444445, 5.555555555555555, + 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0), (0.0, 1.1111111111111112, 2.2222222222222223, + 3.3333333333333335, 4.444444444444445, 5.555555555555555, 6.666666666666667, 7.777777777777779, 8.88888888888889, 10.0)) + + assert ramp_res_tester(tf1, 6, exp1) + assert ramp_res_tester(tf2, 10, exp2, 1.2) + assert ramp_res_tester(tf3, 10, exp3, 1.5) + assert ramp_res_tester(tf4, 10, exp4, 3) + assert ramp_res_tester(tf5, 10, exp5, 9) + assert ramp_res_tester(tf6, 10, exp6) diff --git a/lib/python3.12/site-packages/sympy/physics/control/tests/test_lti.py b/lib/python3.12/site-packages/sympy/physics/control/tests/test_lti.py new file mode 100644 index 0000000000000000000000000000000000000000..9a3f599cbe240827cf24c7473782f7b71ad9a562 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/control/tests/test_lti.py @@ -0,0 +1,1750 @@ +from sympy.core.add import Add +from sympy.core.function import Function +from sympy.core.mul import Mul +from sympy.core.numbers import (I, pi, Rational, oo) +from sympy.core.power import Pow +from sympy.core.singleton import S +from sympy.core.symbol import symbols +from sympy.functions.elementary.exponential import (exp, log) +from sympy.functions.elementary.miscellaneous import sqrt +from sympy.functions.elementary.trigonometric import atan +from sympy.matrices.dense import eye +from sympy.polys.polytools import factor +from sympy.polys.rootoftools import CRootOf +from sympy.simplify.simplify import simplify +from sympy.core.containers import Tuple +from sympy.matrices import ImmutableMatrix, Matrix, ShapeError +from sympy.physics.control import (TransferFunction, Series, Parallel, + Feedback, TransferFunctionMatrix, MIMOSeries, MIMOParallel, MIMOFeedback, + StateSpace, gbt, bilinear, forward_diff, backward_diff, phase_margin, gain_margin) +from sympy.testing.pytest import raises + +a, x, b, c, s, g, d, p, k, tau, zeta, wn, T = symbols('a, x, b, c, s, g, d, p, k,\ + tau, zeta, wn, T') +a0, a1, a2, a3, b0, b1, b2, b3, c0, c1, c2, c3, d0, d1, d2, d3 = symbols('a0:4,\ + b0:4, c0:4, d0:4') +TF1 = TransferFunction(1, s**2 + 2*zeta*wn*s + wn**2, s) +TF2 = TransferFunction(k, 1, s) +TF3 = TransferFunction(a2*p - s, a2*s + p, s) + + +def test_TransferFunction_construction(): + tf = TransferFunction(s + 1, s**2 + s + 1, s) + assert tf.num == (s + 1) + assert tf.den == (s**2 + s + 1) + assert tf.args == (s + 1, s**2 + s + 1, s) + + tf1 = TransferFunction(s + 4, s - 5, s) + assert tf1.num == (s + 4) + assert tf1.den == (s - 5) + assert tf1.args == (s + 4, s - 5, s) + + # using different polynomial variables. + tf2 = TransferFunction(p + 3, p**2 - 9, p) + assert tf2.num == (p + 3) + assert tf2.den == (p**2 - 9) + assert tf2.args == (p + 3, p**2 - 9, p) + + tf3 = TransferFunction(p**3 + 5*p**2 + 4, p**4 + 3*p + 1, p) + assert tf3.args == (p**3 + 5*p**2 + 4, p**4 + 3*p + 1, p) + + # no pole-zero cancellation on its own. + tf4 = TransferFunction((s + 3)*(s - 1), (s - 1)*(s + 5), s) + assert tf4.den == (s - 1)*(s + 5) + assert tf4.args == ((s + 3)*(s - 1), (s - 1)*(s + 5), s) + + tf4_ = TransferFunction(p + 2, p + 2, p) + assert tf4_.args == (p + 2, p + 2, p) + + tf5 = TransferFunction(s - 1, 4 - p, s) + assert tf5.args == (s - 1, 4 - p, s) + + tf5_ = TransferFunction(s - 1, s - 1, s) + assert tf5_.args == (s - 1, s - 1, s) + + tf6 = TransferFunction(5, 6, s) + assert tf6.num == 5 + assert tf6.den == 6 + assert tf6.args == (5, 6, s) + + tf6_ = TransferFunction(1/2, 4, s) + assert tf6_.num == 0.5 + assert tf6_.den == 4 + assert tf6_.args == (0.500000000000000, 4, s) + + tf7 = TransferFunction(3*s**2 + 2*p + 4*s, 8*p**2 + 7*s, s) + tf8 = TransferFunction(3*s**2 + 2*p + 4*s, 8*p**2 + 7*s, p) + assert not tf7 == tf8 + + tf7_ = TransferFunction(a0*s + a1*s**2 + a2*s**3, b0*p - b1*s, s) + tf8_ = TransferFunction(a0*s + a1*s**2 + a2*s**3, b0*p - b1*s, s) + assert tf7_ == tf8_ + assert -(-tf7_) == tf7_ == -(-(-(-tf7_))) + + tf9 = TransferFunction(a*s**3 + b*s**2 + g*s + d, d*p + g*p**2 + g*s, s) + assert tf9.args == (a*s**3 + b*s**2 + d + g*s, d*p + g*p**2 + g*s, s) + + tf10 = TransferFunction(p**3 + d, g*s**2 + d*s + a, p) + tf10_ = TransferFunction(p**3 + d, g*s**2 + d*s + a, p) + assert tf10.args == (d + p**3, a + d*s + g*s**2, p) + assert tf10_ == tf10 + + tf11 = TransferFunction(a1*s + a0, b2*s**2 + b1*s + b0, s) + assert tf11.num == (a0 + a1*s) + assert tf11.den == (b0 + b1*s + b2*s**2) + assert tf11.args == (a0 + a1*s, b0 + b1*s + b2*s**2, s) + + # when just the numerator is 0, leave the denominator alone. + tf12 = TransferFunction(0, p**2 - p + 1, p) + assert tf12.args == (0, p**2 - p + 1, p) + + tf13 = TransferFunction(0, 1, s) + assert tf13.args == (0, 1, s) + + # float exponents + tf14 = TransferFunction(a0*s**0.5 + a2*s**0.6 - a1, a1*p**(-8.7), s) + assert tf14.args == (a0*s**0.5 - a1 + a2*s**0.6, a1*p**(-8.7), s) + + tf15 = TransferFunction(a2**2*p**(1/4) + a1*s**(-4/5), a0*s - p, p) + assert tf15.args == (a1*s**(-0.8) + a2**2*p**0.25, a0*s - p, p) + + omega_o, k_p, k_o, k_i = symbols('omega_o, k_p, k_o, k_i') + tf18 = TransferFunction((k_p + k_o*s + k_i/s), s**2 + 2*omega_o*s + omega_o**2, s) + assert tf18.num == k_i/s + k_o*s + k_p + assert tf18.args == (k_i/s + k_o*s + k_p, omega_o**2 + 2*omega_o*s + s**2, s) + + # ValueError when denominator is zero. + raises(ValueError, lambda: TransferFunction(4, 0, s)) + raises(ValueError, lambda: TransferFunction(s, 0, s)) + raises(ValueError, lambda: TransferFunction(0, 0, s)) + + raises(TypeError, lambda: TransferFunction(Matrix([1, 2, 3]), s, s)) + + raises(TypeError, lambda: TransferFunction(s**2 + 2*s - 1, s + 3, 3)) + raises(TypeError, lambda: TransferFunction(p + 1, 5 - p, 4)) + raises(TypeError, lambda: TransferFunction(3, 4, 8)) + + +def test_TransferFunction_functions(): + # classmethod from_rational_expression + expr_1 = Mul(0, Pow(s, -1, evaluate=False), evaluate=False) + expr_2 = s/0 + expr_3 = (p*s**2 + 5*s)/(s + 1)**3 + expr_4 = 6 + expr_5 = ((2 + 3*s)*(5 + 2*s))/((9 + 3*s)*(5 + 2*s**2)) + expr_6 = (9*s**4 + 4*s**2 + 8)/((s + 1)*(s + 9)) + tf = TransferFunction(s + 1, s**2 + 2, s) + delay = exp(-s/tau) + expr_7 = delay*tf.to_expr() + H1 = TransferFunction.from_rational_expression(expr_7, s) + H2 = TransferFunction(s + 1, (s**2 + 2)*exp(s/tau), s) + expr_8 = Add(2, 3*s/(s**2 + 1), evaluate=False) + + assert TransferFunction.from_rational_expression(expr_1) == TransferFunction(0, s, s) + raises(ZeroDivisionError, lambda: TransferFunction.from_rational_expression(expr_2)) + raises(ValueError, lambda: TransferFunction.from_rational_expression(expr_3)) + assert TransferFunction.from_rational_expression(expr_3, s) == TransferFunction((p*s**2 + 5*s), (s + 1)**3, s) + assert TransferFunction.from_rational_expression(expr_3, p) == TransferFunction((p*s**2 + 5*s), (s + 1)**3, p) + raises(ValueError, lambda: TransferFunction.from_rational_expression(expr_4)) + assert TransferFunction.from_rational_expression(expr_4, s) == TransferFunction(6, 1, s) + assert TransferFunction.from_rational_expression(expr_5, s) == \ + TransferFunction((2 + 3*s)*(5 + 2*s), (9 + 3*s)*(5 + 2*s**2), s) + assert TransferFunction.from_rational_expression(expr_6, s) == \ + TransferFunction((9*s**4 + 4*s**2 + 8), (s + 1)*(s + 9), s) + assert H1 == H2 + assert TransferFunction.from_rational_expression(expr_8, s) == \ + TransferFunction(2*s**2 + 3*s + 2, s**2 + 1, s) + + # classmethod from_coeff_lists + tf1 = TransferFunction.from_coeff_lists([1, 2], [3, 4, 5], s) + num2 = [p**2, 2*p] + den2 = [p**3, p + 1, 4] + tf2 = TransferFunction.from_coeff_lists(num2, den2, s) + num3 = [1, 2, 3] + den3 = [0, 0] + + assert tf1 == TransferFunction(s + 2, 3*s**2 + 4*s + 5, s) + assert tf2 == TransferFunction(p**2*s + 2*p, p**3*s**2 + s*(p + 1) + 4, s) + raises(ZeroDivisionError, lambda: TransferFunction.from_coeff_lists(num3, den3, s)) + + # classmethod from_zpk + zeros = [4] + poles = [-1+2j, -1-2j] + gain = 3 + tf1 = TransferFunction.from_zpk(zeros, poles, gain, s) + + assert tf1 == TransferFunction(3*s - 12, (s + 1.0 - 2.0*I)*(s + 1.0 + 2.0*I), s) + + # explicitly cancel poles and zeros. + tf0 = TransferFunction(s**5 + s**3 + s, s - s**2, s) + a = TransferFunction(-(s**4 + s**2 + 1), s - 1, s) + assert tf0.simplify() == simplify(tf0) == a + + tf1 = TransferFunction((p + 3)*(p - 1), (p - 1)*(p + 5), p) + b = TransferFunction(p + 3, p + 5, p) + assert tf1.simplify() == simplify(tf1) == b + + # expand the numerator and the denominator. + G1 = TransferFunction((1 - s)**2, (s**2 + 1)**2, s) + G2 = TransferFunction(1, -3, p) + c = (a2*s**p + a1*s**s + a0*p**p)*(p**s + s**p) + d = (b0*s**s + b1*p**s)*(b2*s*p + p**p) + e = a0*p**p*p**s + a0*p**p*s**p + a1*p**s*s**s + a1*s**p*s**s + a2*p**s*s**p + a2*s**(2*p) + f = b0*b2*p*s*s**s + b0*p**p*s**s + b1*b2*p*p**s*s + b1*p**p*p**s + g = a1*a2*s*s**p + a1*p*s + a2*b1*p*s*s**p + b1*p**2*s + G3 = TransferFunction(c, d, s) + G4 = TransferFunction(a0*s**s - b0*p**p, (a1*s + b1*s*p)*(a2*s**p + p), p) + + assert G1.expand() == TransferFunction(s**2 - 2*s + 1, s**4 + 2*s**2 + 1, s) + assert tf1.expand() == TransferFunction(p**2 + 2*p - 3, p**2 + 4*p - 5, p) + assert G2.expand() == G2 + assert G3.expand() == TransferFunction(e, f, s) + assert G4.expand() == TransferFunction(a0*s**s - b0*p**p, g, p) + + # purely symbolic polynomials. + p1 = a1*s + a0 + p2 = b2*s**2 + b1*s + b0 + SP1 = TransferFunction(p1, p2, s) + expect1 = TransferFunction(2.0*s + 1.0, 5.0*s**2 + 4.0*s + 3.0, s) + expect1_ = TransferFunction(2*s + 1, 5*s**2 + 4*s + 3, s) + assert SP1.subs({a0: 1, a1: 2, b0: 3, b1: 4, b2: 5}) == expect1_ + assert SP1.subs({a0: 1, a1: 2, b0: 3, b1: 4, b2: 5}).evalf() == expect1 + assert expect1_.evalf() == expect1 + + c1, d0, d1, d2 = symbols('c1, d0:3') + p3, p4 = c1*p, d2*p**3 + d1*p**2 - d0 + SP2 = TransferFunction(p3, p4, p) + expect2 = TransferFunction(2.0*p, 5.0*p**3 + 2.0*p**2 - 3.0, p) + expect2_ = TransferFunction(2*p, 5*p**3 + 2*p**2 - 3, p) + assert SP2.subs({c1: 2, d0: 3, d1: 2, d2: 5}) == expect2_ + assert SP2.subs({c1: 2, d0: 3, d1: 2, d2: 5}).evalf() == expect2 + assert expect2_.evalf() == expect2 + + SP3 = TransferFunction(a0*p**3 + a1*s**2 - b0*s + b1, a1*s + p, s) + expect3 = TransferFunction(2.0*p**3 + 4.0*s**2 - s + 5.0, p + 4.0*s, s) + expect3_ = TransferFunction(2*p**3 + 4*s**2 - s + 5, p + 4*s, s) + assert SP3.subs({a0: 2, a1: 4, b0: 1, b1: 5}) == expect3_ + assert SP3.subs({a0: 2, a1: 4, b0: 1, b1: 5}).evalf() == expect3 + assert expect3_.evalf() == expect3 + + SP4 = TransferFunction(s - a1*p**3, a0*s + p, p) + expect4 = TransferFunction(7.0*p**3 + s, p - s, p) + expect4_ = TransferFunction(7*p**3 + s, p - s, p) + assert SP4.subs({a0: -1, a1: -7}) == expect4_ + assert SP4.subs({a0: -1, a1: -7}).evalf() == expect4 + assert expect4_.evalf() == expect4 + + # evaluate the transfer function at particular frequencies. + assert tf1.eval_frequency(wn) == wn**2/(wn**2 + 4*wn - 5) + 2*wn/(wn**2 + 4*wn - 5) - 3/(wn**2 + 4*wn - 5) + assert G1.eval_frequency(1 + I) == S(3)/25 + S(4)*I/25 + assert G4.eval_frequency(S(5)/3) == \ + a0*s**s/(a1*a2*s**(S(8)/3) + S(5)*a1*s/3 + 5*a2*b1*s**(S(8)/3)/3 + S(25)*b1*s/9) - 5*3**(S(1)/3)*5**(S(2)/3)*b0/(9*a1*a2*s**(S(8)/3) + 15*a1*s + 15*a2*b1*s**(S(8)/3) + 25*b1*s) + + # Low-frequency (or DC) gain. + assert tf0.dc_gain() == 1 + assert tf1.dc_gain() == Rational(3, 5) + assert SP2.dc_gain() == 0 + assert expect4.dc_gain() == -1 + assert expect2_.dc_gain() == 0 + assert TransferFunction(1, s, s).dc_gain() == oo + + # Poles of a transfer function. + tf_ = TransferFunction(x**3 - k, k, x) + _tf = TransferFunction(k, x**4 - k, x) + TF_ = TransferFunction(x**2, x**10 + x + x**2, x) + _TF = TransferFunction(x**10 + x + x**2, x**2, x) + assert G1.poles() == [I, I, -I, -I] + assert G2.poles() == [] + assert tf1.poles() == [-5, 1] + assert expect4_.poles() == [s] + assert SP4.poles() == [-a0*s] + assert expect3.poles() == [-0.25*p] + assert str(expect2.poles()) == str([0.729001428685125, -0.564500714342563 - 0.710198984796332*I, -0.564500714342563 + 0.710198984796332*I]) + assert str(expect1.poles()) == str([-0.4 - 0.66332495807108*I, -0.4 + 0.66332495807108*I]) + assert _tf.poles() == [k**(Rational(1, 4)), -k**(Rational(1, 4)), I*k**(Rational(1, 4)), -I*k**(Rational(1, 4))] + assert TF_.poles() == [CRootOf(x**9 + x + 1, 0), 0, CRootOf(x**9 + x + 1, 1), CRootOf(x**9 + x + 1, 2), + CRootOf(x**9 + x + 1, 3), CRootOf(x**9 + x + 1, 4), CRootOf(x**9 + x + 1, 5), CRootOf(x**9 + x + 1, 6), + CRootOf(x**9 + x + 1, 7), CRootOf(x**9 + x + 1, 8)] + raises(NotImplementedError, lambda: TransferFunction(x**2, a0*x**10 + x + x**2, x).poles()) + + # Stability of a transfer function. + q, r = symbols('q, r', negative=True) + t = symbols('t', positive=True) + TF_ = TransferFunction(s**2 + a0 - a1*p, q*s - r, s) + stable_tf = TransferFunction(s**2 + a0 - a1*p, q*s - 1, s) + stable_tf_ = TransferFunction(s**2 + a0 - a1*p, q*s - t, s) + + assert G1.is_stable() is False + assert G2.is_stable() is True + assert tf1.is_stable() is False # as one pole is +ve, and the other is -ve. + assert expect2.is_stable() is False + assert expect1.is_stable() is True + assert stable_tf.is_stable() is True + assert stable_tf_.is_stable() is True + assert TF_.is_stable() is False + assert expect4_.is_stable() is None # no assumption provided for the only pole 's'. + assert SP4.is_stable() is None + + # Zeros of a transfer function. + assert G1.zeros() == [1, 1] + assert G2.zeros() == [] + assert tf1.zeros() == [-3, 1] + assert expect4_.zeros() == [7**(Rational(2, 3))*(-s)**(Rational(1, 3))/7, -7**(Rational(2, 3))*(-s)**(Rational(1, 3))/14 - + sqrt(3)*7**(Rational(2, 3))*I*(-s)**(Rational(1, 3))/14, -7**(Rational(2, 3))*(-s)**(Rational(1, 3))/14 + sqrt(3)*7**(Rational(2, 3))*I*(-s)**(Rational(1, 3))/14] + assert SP4.zeros() == [(s/a1)**(Rational(1, 3)), -(s/a1)**(Rational(1, 3))/2 - sqrt(3)*I*(s/a1)**(Rational(1, 3))/2, + -(s/a1)**(Rational(1, 3))/2 + sqrt(3)*I*(s/a1)**(Rational(1, 3))/2] + assert str(expect3.zeros()) == str([0.125 - 1.11102430216445*sqrt(-0.405063291139241*p**3 - 1.0), + 1.11102430216445*sqrt(-0.405063291139241*p**3 - 1.0) + 0.125]) + assert tf_.zeros() == [k**(Rational(1, 3)), -k**(Rational(1, 3))/2 - sqrt(3)*I*k**(Rational(1, 3))/2, + -k**(Rational(1, 3))/2 + sqrt(3)*I*k**(Rational(1, 3))/2] + assert _TF.zeros() == [CRootOf(x**9 + x + 1, 0), 0, CRootOf(x**9 + x + 1, 1), CRootOf(x**9 + x + 1, 2), + CRootOf(x**9 + x + 1, 3), CRootOf(x**9 + x + 1, 4), CRootOf(x**9 + x + 1, 5), CRootOf(x**9 + x + 1, 6), + CRootOf(x**9 + x + 1, 7), CRootOf(x**9 + x + 1, 8)] + raises(NotImplementedError, lambda: TransferFunction(a0*x**10 + x + x**2, x**2, x).zeros()) + + # negation of TF. + tf2 = TransferFunction(s + 3, s**2 - s**3 + 9, s) + tf3 = TransferFunction(-3*p + 3, 1 - p, p) + assert -tf2 == TransferFunction(-s - 3, s**2 - s**3 + 9, s) + assert -tf3 == TransferFunction(3*p - 3, 1 - p, p) + + # taking power of a TF. + tf4 = TransferFunction(p + 4, p - 3, p) + tf5 = TransferFunction(s**2 + 1, 1 - s, s) + expect2 = TransferFunction((s**2 + 1)**3, (1 - s)**3, s) + expect1 = TransferFunction((p + 4)**2, (p - 3)**2, p) + assert (tf4*tf4).doit() == tf4**2 == pow(tf4, 2) == expect1 + assert (tf5*tf5*tf5).doit() == tf5**3 == pow(tf5, 3) == expect2 + assert tf5**0 == pow(tf5, 0) == TransferFunction(1, 1, s) + assert Series(tf4).doit()**-1 == tf4**-1 == pow(tf4, -1) == TransferFunction(p - 3, p + 4, p) + assert (tf5*tf5).doit()**-1 == tf5**-2 == pow(tf5, -2) == TransferFunction((1 - s)**2, (s**2 + 1)**2, s) + + raises(ValueError, lambda: tf4**(s**2 + s - 1)) + raises(ValueError, lambda: tf5**s) + raises(ValueError, lambda: tf4**tf5) + + # SymPy's own functions. + tf = TransferFunction(s - 1, s**2 - 2*s + 1, s) + tf6 = TransferFunction(s + p, p**2 - 5, s) + assert factor(tf) == TransferFunction(s - 1, (s - 1)**2, s) + assert tf.num.subs(s, 2) == tf.den.subs(s, 2) == 1 + # subs & xreplace + assert tf.subs(s, 2) == TransferFunction(s - 1, s**2 - 2*s + 1, s) + assert tf6.subs(p, 3) == TransferFunction(s + 3, 4, s) + assert tf3.xreplace({p: s}) == TransferFunction(-3*s + 3, 1 - s, s) + raises(TypeError, lambda: tf3.xreplace({p: exp(2)})) + assert tf3.subs(p, exp(2)) == tf3 + + tf7 = TransferFunction(a0*s**p + a1*p**s, a2*p - s, s) + assert tf7.xreplace({s: k}) == TransferFunction(a0*k**p + a1*p**k, a2*p - k, k) + assert tf7.subs(s, k) == TransferFunction(a0*s**p + a1*p**s, a2*p - s, s) + + # Conversion to Expr with to_expr() + tf8 = TransferFunction(a0*s**5 + 5*s**2 + 3, s**6 - 3, s) + tf9 = TransferFunction((5 + s), (5 + s)*(6 + s), s) + tf10 = TransferFunction(0, 1, s) + tf11 = TransferFunction(1, 1, s) + assert tf8.to_expr() == Mul((a0*s**5 + 5*s**2 + 3), Pow((s**6 - 3), -1, evaluate=False), evaluate=False) + assert tf9.to_expr() == Mul((s + 5), Pow((5 + s)*(6 + s), -1, evaluate=False), evaluate=False) + assert tf10.to_expr() == Mul(S(0), Pow(1, -1, evaluate=False), evaluate=False) + assert tf11.to_expr() == Pow(1, -1, evaluate=False) + +def test_TransferFunction_addition_and_subtraction(): + tf1 = TransferFunction(s + 6, s - 5, s) + tf2 = TransferFunction(s + 3, s + 1, s) + tf3 = TransferFunction(s + 1, s**2 + s + 1, s) + tf4 = TransferFunction(p, 2 - p, p) + + # addition + assert tf1 + tf2 == Parallel(tf1, tf2) + assert tf3 + tf1 == Parallel(tf3, tf1) + assert -tf1 + tf2 + tf3 == Parallel(-tf1, tf2, tf3) + assert tf1 + (tf2 + tf3) == Parallel(tf1, tf2, tf3) + + c = symbols("c", commutative=False) + raises(ValueError, lambda: tf1 + Matrix([1, 2, 3])) + raises(ValueError, lambda: tf2 + c) + raises(ValueError, lambda: tf3 + tf4) + raises(ValueError, lambda: tf1 + (s - 1)) + raises(ValueError, lambda: tf1 + 8) + raises(ValueError, lambda: (1 - p**3) + tf1) + + # subtraction + assert tf1 - tf2 == Parallel(tf1, -tf2) + assert tf3 - tf2 == Parallel(tf3, -tf2) + assert -tf1 - tf3 == Parallel(-tf1, -tf3) + assert tf1 - tf2 + tf3 == Parallel(tf1, -tf2, tf3) + + raises(ValueError, lambda: tf1 - Matrix([1, 2, 3])) + raises(ValueError, lambda: tf3 - tf4) + raises(ValueError, lambda: tf1 - (s - 1)) + raises(ValueError, lambda: tf1 - 8) + raises(ValueError, lambda: (s + 5) - tf2) + raises(ValueError, lambda: (1 + p**4) - tf1) + + +def test_TransferFunction_multiplication_and_division(): + G1 = TransferFunction(s + 3, -s**3 + 9, s) + G2 = TransferFunction(s + 1, s - 5, s) + G3 = TransferFunction(p, p**4 - 6, p) + G4 = TransferFunction(p + 4, p - 5, p) + G5 = TransferFunction(s + 6, s - 5, s) + G6 = TransferFunction(s + 3, s + 1, s) + G7 = TransferFunction(1, 1, s) + + # multiplication + assert G1*G2 == Series(G1, G2) + assert -G1*G5 == Series(-G1, G5) + assert -G2*G5*-G6 == Series(-G2, G5, -G6) + assert -G1*-G2*-G5*-G6 == Series(-G1, -G2, -G5, -G6) + assert G3*G4 == Series(G3, G4) + assert (G1*G2)*-(G5*G6) == \ + Series(G1, G2, TransferFunction(-1, 1, s), Series(G5, G6)) + assert G1*G2*(G5 + G6) == Series(G1, G2, Parallel(G5, G6)) + + # division - See ``test_Feedback_functions()`` for division by Parallel objects. + assert G5/G6 == Series(G5, pow(G6, -1)) + assert -G3/G4 == Series(-G3, pow(G4, -1)) + assert (G5*G6)/G7 == Series(G5, G6, pow(G7, -1)) + + c = symbols("c", commutative=False) + raises(ValueError, lambda: G3 * Matrix([1, 2, 3])) + raises(ValueError, lambda: G1 * c) + raises(ValueError, lambda: G3 * G5) + raises(ValueError, lambda: G5 * (s - 1)) + raises(ValueError, lambda: 9 * G5) + + raises(ValueError, lambda: G3 / Matrix([1, 2, 3])) + raises(ValueError, lambda: G6 / 0) + raises(ValueError, lambda: G3 / G5) + raises(ValueError, lambda: G5 / 2) + raises(ValueError, lambda: G5 / s**2) + raises(ValueError, lambda: (s - 4*s**2) / G2) + raises(ValueError, lambda: 0 / G4) + raises(ValueError, lambda: G7 / (1 + G6)) + raises(ValueError, lambda: G7 / (G5 * G6)) + raises(ValueError, lambda: G7 / (G7 + (G5 + G6))) + + +def test_TransferFunction_is_proper(): + omega_o, zeta, tau = symbols('omega_o, zeta, tau') + G1 = TransferFunction(omega_o**2, s**2 + p*omega_o*zeta*s + omega_o**2, omega_o) + G2 = TransferFunction(tau - s**3, tau + p**4, tau) + G3 = TransferFunction(a*b*s**3 + s**2 - a*p + s, b - s*p**2, p) + G4 = TransferFunction(b*s**2 + p**2 - a*p + s, b - p**2, s) + assert G1.is_proper + assert G2.is_proper + assert G3.is_proper + assert not G4.is_proper + + +def test_TransferFunction_is_strictly_proper(): + omega_o, zeta, tau = symbols('omega_o, zeta, tau') + tf1 = TransferFunction(omega_o**2, s**2 + p*omega_o*zeta*s + omega_o**2, omega_o) + tf2 = TransferFunction(tau - s**3, tau + p**4, tau) + tf3 = TransferFunction(a*b*s**3 + s**2 - a*p + s, b - s*p**2, p) + tf4 = TransferFunction(b*s**2 + p**2 - a*p + s, b - p**2, s) + assert not tf1.is_strictly_proper + assert not tf2.is_strictly_proper + assert tf3.is_strictly_proper + assert not tf4.is_strictly_proper + + +def test_TransferFunction_is_biproper(): + tau, omega_o, zeta = symbols('tau, omega_o, zeta') + tf1 = TransferFunction(omega_o**2, s**2 + p*omega_o*zeta*s + omega_o**2, omega_o) + tf2 = TransferFunction(tau - s**3, tau + p**4, tau) + tf3 = TransferFunction(a*b*s**3 + s**2 - a*p + s, b - s*p**2, p) + tf4 = TransferFunction(b*s**2 + p**2 - a*p + s, b - p**2, s) + assert tf1.is_biproper + assert tf2.is_biproper + assert not tf3.is_biproper + assert not tf4.is_biproper + + +def test_Series_construction(): + tf = TransferFunction(a0*s**3 + a1*s**2 - a2*s, b0*p**4 + b1*p**3 - b2*s*p, s) + tf2 = TransferFunction(a2*p - s, a2*s + p, s) + tf3 = TransferFunction(a0*p + p**a1 - s, p, p) + tf4 = TransferFunction(1, s**2 + 2*zeta*wn*s + wn**2, s) + inp = Function('X_d')(s) + out = Function('X')(s) + + s0 = Series(tf, tf2) + assert s0.args == (tf, tf2) + assert s0.var == s + + s1 = Series(Parallel(tf, -tf2), tf2) + assert s1.args == (Parallel(tf, -tf2), tf2) + assert s1.var == s + + tf3_ = TransferFunction(inp, 1, s) + tf4_ = TransferFunction(-out, 1, s) + s2 = Series(tf, Parallel(tf3_, tf4_), tf2) + assert s2.args == (tf, Parallel(tf3_, tf4_), tf2) + + s3 = Series(tf, tf2, tf4) + assert s3.args == (tf, tf2, tf4) + + s4 = Series(tf3_, tf4_) + assert s4.args == (tf3_, tf4_) + assert s4.var == s + + s6 = Series(tf2, tf4, Parallel(tf2, -tf), tf4) + assert s6.args == (tf2, tf4, Parallel(tf2, -tf), tf4) + + s7 = Series(tf, tf2) + assert s0 == s7 + assert not s0 == s2 + + raises(ValueError, lambda: Series(tf, tf3)) + raises(ValueError, lambda: Series(tf, tf2, tf3, tf4)) + raises(ValueError, lambda: Series(-tf3, tf2)) + raises(TypeError, lambda: Series(2, tf, tf4)) + raises(TypeError, lambda: Series(s**2 + p*s, tf3, tf2)) + raises(TypeError, lambda: Series(tf3, Matrix([1, 2, 3, 4]))) + + +def test_MIMOSeries_construction(): + tf_1 = TransferFunction(a0*s**3 + a1*s**2 - a2*s, b0*p**4 + b1*p**3 - b2*s*p, s) + tf_2 = TransferFunction(a2*p - s, a2*s + p, s) + tf_3 = TransferFunction(1, s**2 + 2*zeta*wn*s + wn**2, s) + + tfm_1 = TransferFunctionMatrix([[tf_1, tf_2, tf_3], [-tf_3, -tf_2, tf_1]]) + tfm_2 = TransferFunctionMatrix([[-tf_2], [-tf_2], [-tf_3]]) + tfm_3 = TransferFunctionMatrix([[-tf_3]]) + tfm_4 = TransferFunctionMatrix([[TF3], [TF2], [-TF1]]) + tfm_5 = TransferFunctionMatrix.from_Matrix(Matrix([1/p]), p) + + s8 = MIMOSeries(tfm_2, tfm_1) + assert s8.args == (tfm_2, tfm_1) + assert s8.var == s + assert s8.shape == (s8.num_outputs, s8.num_inputs) == (2, 1) + + s9 = MIMOSeries(tfm_3, tfm_2, tfm_1) + assert s9.args == (tfm_3, tfm_2, tfm_1) + assert s9.var == s + assert s9.shape == (s9.num_outputs, s9.num_inputs) == (2, 1) + + s11 = MIMOSeries(tfm_3, MIMOParallel(-tfm_2, -tfm_4), tfm_1) + assert s11.args == (tfm_3, MIMOParallel(-tfm_2, -tfm_4), tfm_1) + assert s11.shape == (s11.num_outputs, s11.num_inputs) == (2, 1) + + # arg cannot be empty tuple. + raises(ValueError, lambda: MIMOSeries()) + + # arg cannot contain SISO as well as MIMO systems. + raises(TypeError, lambda: MIMOSeries(tfm_1, tf_1)) + + # for all the adjacent transfer function matrices: + # no. of inputs of first TFM must be equal to the no. of outputs of the second TFM. + raises(ValueError, lambda: MIMOSeries(tfm_1, tfm_2, -tfm_1)) + + # all the TFMs must use the same complex variable. + raises(ValueError, lambda: MIMOSeries(tfm_3, tfm_5)) + + # Number or expression not allowed in the arguments. + raises(TypeError, lambda: MIMOSeries(2, tfm_2, tfm_3)) + raises(TypeError, lambda: MIMOSeries(s**2 + p*s, -tfm_2, tfm_3)) + raises(TypeError, lambda: MIMOSeries(Matrix([1/p]), tfm_3)) + + +def test_Series_functions(): + tf1 = TransferFunction(1, s**2 + 2*zeta*wn*s + wn**2, s) + tf2 = TransferFunction(k, 1, s) + tf3 = TransferFunction(a2*p - s, a2*s + p, s) + tf4 = TransferFunction(a0*p + p**a1 - s, p, p) + tf5 = TransferFunction(a1*s**2 + a2*s - a0, s + a0, s) + + assert tf1*tf2*tf3 == Series(tf1, tf2, tf3) == Series(Series(tf1, tf2), tf3) \ + == Series(tf1, Series(tf2, tf3)) + assert tf1*(tf2 + tf3) == Series(tf1, Parallel(tf2, tf3)) + assert tf1*tf2 + tf5 == Parallel(Series(tf1, tf2), tf5) + assert tf1*tf2 - tf5 == Parallel(Series(tf1, tf2), -tf5) + assert tf1*tf2 + tf3 + tf5 == Parallel(Series(tf1, tf2), tf3, tf5) + assert tf1*tf2 - tf3 - tf5 == Parallel(Series(tf1, tf2), -tf3, -tf5) + assert tf1*tf2 - tf3 + tf5 == Parallel(Series(tf1, tf2), -tf3, tf5) + assert tf1*tf2 + tf3*tf5 == Parallel(Series(tf1, tf2), Series(tf3, tf5)) + assert tf1*tf2 - tf3*tf5 == Parallel(Series(tf1, tf2), Series(TransferFunction(-1, 1, s), Series(tf3, tf5))) + assert tf2*tf3*(tf2 - tf1)*tf3 == Series(tf2, tf3, Parallel(tf2, -tf1), tf3) + assert -tf1*tf2 == Series(-tf1, tf2) + assert -(tf1*tf2) == Series(TransferFunction(-1, 1, s), Series(tf1, tf2)) + raises(ValueError, lambda: tf1*tf2*tf4) + raises(ValueError, lambda: tf1*(tf2 - tf4)) + raises(ValueError, lambda: tf3*Matrix([1, 2, 3])) + + # evaluate=True -> doit() + assert Series(tf1, tf2, evaluate=True) == Series(tf1, tf2).doit() == \ + TransferFunction(k, s**2 + 2*s*wn*zeta + wn**2, s) + assert Series(tf1, tf2, Parallel(tf1, -tf3), evaluate=True) == Series(tf1, tf2, Parallel(tf1, -tf3)).doit() == \ + TransferFunction(k*(a2*s + p + (-a2*p + s)*(s**2 + 2*s*wn*zeta + wn**2)), (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2)**2, s) + assert Series(tf2, tf1, -tf3, evaluate=True) == Series(tf2, tf1, -tf3).doit() == \ + TransferFunction(k*(-a2*p + s), (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s) + assert not Series(tf1, -tf2, evaluate=False) == Series(tf1, -tf2).doit() + + assert Series(Parallel(tf1, tf2), Parallel(tf2, -tf3)).doit() == \ + TransferFunction((k*(s**2 + 2*s*wn*zeta + wn**2) + 1)*(-a2*p + k*(a2*s + p) + s), (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s) + assert Series(-tf1, -tf2, -tf3).doit() == \ + TransferFunction(k*(-a2*p + s), (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s) + assert -Series(tf1, tf2, tf3).doit() == \ + TransferFunction(-k*(a2*p - s), (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s) + assert Series(tf2, tf3, Parallel(tf2, -tf1), tf3).doit() == \ + TransferFunction(k*(a2*p - s)**2*(k*(s**2 + 2*s*wn*zeta + wn**2) - 1), (a2*s + p)**2*(s**2 + 2*s*wn*zeta + wn**2), s) + + assert Series(tf1, tf2).rewrite(TransferFunction) == TransferFunction(k, s**2 + 2*s*wn*zeta + wn**2, s) + assert Series(tf2, tf1, -tf3).rewrite(TransferFunction) == \ + TransferFunction(k*(-a2*p + s), (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s) + + S1 = Series(Parallel(tf1, tf2), Parallel(tf2, -tf3)) + assert S1.is_proper + assert not S1.is_strictly_proper + assert S1.is_biproper + + S2 = Series(tf1, tf2, tf3) + assert S2.is_proper + assert S2.is_strictly_proper + assert not S2.is_biproper + + S3 = Series(tf1, -tf2, Parallel(tf1, -tf3)) + assert S3.is_proper + assert S3.is_strictly_proper + assert not S3.is_biproper + + +def test_MIMOSeries_functions(): + tfm1 = TransferFunctionMatrix([[TF1, TF2, TF3], [-TF3, -TF2, TF1]]) + tfm2 = TransferFunctionMatrix([[-TF1], [-TF2], [-TF3]]) + tfm3 = TransferFunctionMatrix([[-TF1]]) + tfm4 = TransferFunctionMatrix([[-TF2, -TF3], [-TF1, TF2]]) + tfm5 = TransferFunctionMatrix([[TF2, -TF2], [-TF3, -TF2]]) + tfm6 = TransferFunctionMatrix([[-TF3], [TF1]]) + tfm7 = TransferFunctionMatrix([[TF1], [-TF2]]) + + assert tfm1*tfm2 + tfm6 == MIMOParallel(MIMOSeries(tfm2, tfm1), tfm6) + assert tfm1*tfm2 + tfm7 + tfm6 == MIMOParallel(MIMOSeries(tfm2, tfm1), tfm7, tfm6) + assert tfm1*tfm2 - tfm6 - tfm7 == MIMOParallel(MIMOSeries(tfm2, tfm1), -tfm6, -tfm7) + assert tfm4*tfm5 + (tfm4 - tfm5) == MIMOParallel(MIMOSeries(tfm5, tfm4), tfm4, -tfm5) + assert tfm4*-tfm6 + (-tfm4*tfm6) == MIMOParallel(MIMOSeries(-tfm6, tfm4), MIMOSeries(tfm6, -tfm4)) + + raises(ValueError, lambda: tfm1*tfm2 + TF1) + raises(TypeError, lambda: tfm1*tfm2 + a0) + raises(TypeError, lambda: tfm4*tfm6 - (s - 1)) + raises(TypeError, lambda: tfm4*-tfm6 - 8) + raises(TypeError, lambda: (-1 + p**5) + tfm1*tfm2) + + # Shape criteria. + + raises(TypeError, lambda: -tfm1*tfm2 + tfm4) + raises(TypeError, lambda: tfm1*tfm2 - tfm4 + tfm5) + raises(TypeError, lambda: tfm1*tfm2 - tfm4*tfm5) + + assert tfm1*tfm2*-tfm3 == MIMOSeries(-tfm3, tfm2, tfm1) + assert (tfm1*-tfm2)*tfm3 == MIMOSeries(tfm3, -tfm2, tfm1) + + # Multiplication of a Series object with a SISO TF not allowed. + + raises(ValueError, lambda: tfm4*tfm5*TF1) + raises(TypeError, lambda: tfm4*tfm5*a1) + raises(TypeError, lambda: tfm4*-tfm5*(s - 2)) + raises(TypeError, lambda: tfm5*tfm4*9) + raises(TypeError, lambda: (-p**3 + 1)*tfm5*tfm4) + + # Transfer function matrix in the arguments. + assert (MIMOSeries(tfm2, tfm1, evaluate=True) == MIMOSeries(tfm2, tfm1).doit() + == TransferFunctionMatrix(((TransferFunction(-k**2*(a2*s + p)**2*(s**2 + 2*s*wn*zeta + wn**2)**2 + (-a2*p + s)*(a2*p - s)*(s**2 + 2*s*wn*zeta + wn**2)**2 - (a2*s + p)**2, + (a2*s + p)**2*(s**2 + 2*s*wn*zeta + wn**2)**2, s),), + (TransferFunction(k**2*(a2*s + p)**2*(s**2 + 2*s*wn*zeta + wn**2)**2 + (-a2*p + s)*(a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2) + (a2*p - s)*(a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), + (a2*s + p)**2*(s**2 + 2*s*wn*zeta + wn**2)**2, s),)))) + + # doit() should not cancel poles and zeros. + mat_1 = Matrix([[1/(1+s), (1+s)/(1+s**2+2*s)**3]]) + mat_2 = Matrix([[(1+s)], [(1+s**2+2*s)**3/(1+s)]]) + tm_1, tm_2 = TransferFunctionMatrix.from_Matrix(mat_1, s), TransferFunctionMatrix.from_Matrix(mat_2, s) + assert (MIMOSeries(tm_2, tm_1).doit() + == TransferFunctionMatrix(((TransferFunction(2*(s + 1)**2*(s**2 + 2*s + 1)**3, (s + 1)**2*(s**2 + 2*s + 1)**3, s),),))) + assert MIMOSeries(tm_2, tm_1).doit().simplify() == TransferFunctionMatrix(((TransferFunction(2, 1, s),),)) + + # calling doit() will expand the internal Series and Parallel objects. + assert (MIMOSeries(-tfm3, -tfm2, tfm1, evaluate=True) + == MIMOSeries(-tfm3, -tfm2, tfm1).doit() + == TransferFunctionMatrix(((TransferFunction(k**2*(a2*s + p)**2*(s**2 + 2*s*wn*zeta + wn**2)**2 + (a2*p - s)**2*(s**2 + 2*s*wn*zeta + wn**2)**2 + (a2*s + p)**2, + (a2*s + p)**2*(s**2 + 2*s*wn*zeta + wn**2)**3, s),), + (TransferFunction(-k**2*(a2*s + p)**2*(s**2 + 2*s*wn*zeta + wn**2)**2 + (-a2*p + s)*(a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2) + (a2*p - s)*(a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), + (a2*s + p)**2*(s**2 + 2*s*wn*zeta + wn**2)**3, s),)))) + assert (MIMOSeries(MIMOParallel(tfm4, tfm5), tfm5, evaluate=True) + == MIMOSeries(MIMOParallel(tfm4, tfm5), tfm5).doit() + == TransferFunctionMatrix(((TransferFunction(-k*(-a2*s - p + (-a2*p + s)*(s**2 + 2*s*wn*zeta + wn**2)), (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s), TransferFunction(k*(-a2*p - \ + k*(a2*s + p) + s), a2*s + p, s)), (TransferFunction(-k*(-a2*s - p + (-a2*p + s)*(s**2 + 2*s*wn*zeta + wn**2)), (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s), \ + TransferFunction((-a2*p + s)*(-a2*p - k*(a2*s + p) + s), (a2*s + p)**2, s)))) == MIMOSeries(MIMOParallel(tfm4, tfm5), tfm5).rewrite(TransferFunctionMatrix)) + + +def test_Parallel_construction(): + tf = TransferFunction(a0*s**3 + a1*s**2 - a2*s, b0*p**4 + b1*p**3 - b2*s*p, s) + tf2 = TransferFunction(a2*p - s, a2*s + p, s) + tf3 = TransferFunction(a0*p + p**a1 - s, p, p) + tf4 = TransferFunction(1, s**2 + 2*zeta*wn*s + wn**2, s) + inp = Function('X_d')(s) + out = Function('X')(s) + + p0 = Parallel(tf, tf2) + assert p0.args == (tf, tf2) + assert p0.var == s + + p1 = Parallel(Series(tf, -tf2), tf2) + assert p1.args == (Series(tf, -tf2), tf2) + assert p1.var == s + + tf3_ = TransferFunction(inp, 1, s) + tf4_ = TransferFunction(-out, 1, s) + p2 = Parallel(tf, Series(tf3_, -tf4_), tf2) + assert p2.args == (tf, Series(tf3_, -tf4_), tf2) + + p3 = Parallel(tf, tf2, tf4) + assert p3.args == (tf, tf2, tf4) + + p4 = Parallel(tf3_, tf4_) + assert p4.args == (tf3_, tf4_) + assert p4.var == s + + p5 = Parallel(tf, tf2) + assert p0 == p5 + assert not p0 == p1 + + p6 = Parallel(tf2, tf4, Series(tf2, -tf4)) + assert p6.args == (tf2, tf4, Series(tf2, -tf4)) + + p7 = Parallel(tf2, tf4, Series(tf2, -tf), tf4) + assert p7.args == (tf2, tf4, Series(tf2, -tf), tf4) + + raises(ValueError, lambda: Parallel(tf, tf3)) + raises(ValueError, lambda: Parallel(tf, tf2, tf3, tf4)) + raises(ValueError, lambda: Parallel(-tf3, tf4)) + raises(TypeError, lambda: Parallel(2, tf, tf4)) + raises(TypeError, lambda: Parallel(s**2 + p*s, tf3, tf2)) + raises(TypeError, lambda: Parallel(tf3, Matrix([1, 2, 3, 4]))) + + +def test_MIMOParallel_construction(): + tfm1 = TransferFunctionMatrix([[TF1], [TF2], [TF3]]) + tfm2 = TransferFunctionMatrix([[-TF3], [TF2], [TF1]]) + tfm3 = TransferFunctionMatrix([[TF1]]) + tfm4 = TransferFunctionMatrix([[TF2], [TF1], [TF3]]) + tfm5 = TransferFunctionMatrix([[TF1, TF2], [TF2, TF1]]) + tfm6 = TransferFunctionMatrix([[TF2, TF1], [TF1, TF2]]) + tfm7 = TransferFunctionMatrix.from_Matrix(Matrix([[1/p]]), p) + + p8 = MIMOParallel(tfm1, tfm2) + assert p8.args == (tfm1, tfm2) + assert p8.var == s + assert p8.shape == (p8.num_outputs, p8.num_inputs) == (3, 1) + + p9 = MIMOParallel(MIMOSeries(tfm3, tfm1), tfm2) + assert p9.args == (MIMOSeries(tfm3, tfm1), tfm2) + assert p9.var == s + assert p9.shape == (p9.num_outputs, p9.num_inputs) == (3, 1) + + p10 = MIMOParallel(tfm1, MIMOSeries(tfm3, tfm4), tfm2) + assert p10.args == (tfm1, MIMOSeries(tfm3, tfm4), tfm2) + assert p10.var == s + assert p10.shape == (p10.num_outputs, p10.num_inputs) == (3, 1) + + p11 = MIMOParallel(tfm2, tfm1, tfm4) + assert p11.args == (tfm2, tfm1, tfm4) + assert p11.shape == (p11.num_outputs, p11.num_inputs) == (3, 1) + + p12 = MIMOParallel(tfm6, tfm5) + assert p12.args == (tfm6, tfm5) + assert p12.shape == (p12.num_outputs, p12.num_inputs) == (2, 2) + + p13 = MIMOParallel(tfm2, tfm4, MIMOSeries(-tfm3, tfm4), -tfm4) + assert p13.args == (tfm2, tfm4, MIMOSeries(-tfm3, tfm4), -tfm4) + assert p13.shape == (p13.num_outputs, p13.num_inputs) == (3, 1) + + # arg cannot be empty tuple. + raises(TypeError, lambda: MIMOParallel(())) + + # arg cannot contain SISO as well as MIMO systems. + raises(TypeError, lambda: MIMOParallel(tfm1, tfm2, TF1)) + + # all TFMs must have same shapes. + raises(TypeError, lambda: MIMOParallel(tfm1, tfm3, tfm4)) + + # all TFMs must be using the same complex variable. + raises(ValueError, lambda: MIMOParallel(tfm3, tfm7)) + + # Number or expression not allowed in the arguments. + raises(TypeError, lambda: MIMOParallel(2, tfm1, tfm4)) + raises(TypeError, lambda: MIMOParallel(s**2 + p*s, -tfm4, tfm2)) + + +def test_Parallel_functions(): + tf1 = TransferFunction(1, s**2 + 2*zeta*wn*s + wn**2, s) + tf2 = TransferFunction(k, 1, s) + tf3 = TransferFunction(a2*p - s, a2*s + p, s) + tf4 = TransferFunction(a0*p + p**a1 - s, p, p) + tf5 = TransferFunction(a1*s**2 + a2*s - a0, s + a0, s) + + assert tf1 + tf2 + tf3 == Parallel(tf1, tf2, tf3) + assert tf1 + tf2 + tf3 + tf5 == Parallel(tf1, tf2, tf3, tf5) + assert tf1 + tf2 - tf3 - tf5 == Parallel(tf1, tf2, -tf3, -tf5) + assert tf1 + tf2*tf3 == Parallel(tf1, Series(tf2, tf3)) + assert tf1 - tf2*tf3 == Parallel(tf1, -Series(tf2,tf3)) + assert -tf1 - tf2 == Parallel(-tf1, -tf2) + assert -(tf1 + tf2) == Series(TransferFunction(-1, 1, s), Parallel(tf1, tf2)) + assert (tf2 + tf3)*tf1 == Series(Parallel(tf2, tf3), tf1) + assert (tf1 + tf2)*(tf3*tf5) == Series(Parallel(tf1, tf2), tf3, tf5) + assert -(tf2 + tf3)*-tf5 == Series(TransferFunction(-1, 1, s), Parallel(tf2, tf3), -tf5) + assert tf2 + tf3 + tf2*tf1 + tf5 == Parallel(tf2, tf3, Series(tf2, tf1), tf5) + assert tf2 + tf3 + tf2*tf1 - tf3 == Parallel(tf2, tf3, Series(tf2, tf1), -tf3) + assert (tf1 + tf2 + tf5)*(tf3 + tf5) == Series(Parallel(tf1, tf2, tf5), Parallel(tf3, tf5)) + raises(ValueError, lambda: tf1 + tf2 + tf4) + raises(ValueError, lambda: tf1 - tf2*tf4) + raises(ValueError, lambda: tf3 + Matrix([1, 2, 3])) + + # evaluate=True -> doit() + assert Parallel(tf1, tf2, evaluate=True) == Parallel(tf1, tf2).doit() == \ + TransferFunction(k*(s**2 + 2*s*wn*zeta + wn**2) + 1, s**2 + 2*s*wn*zeta + wn**2, s) + assert Parallel(tf1, tf2, Series(-tf1, tf3), evaluate=True) == \ + Parallel(tf1, tf2, Series(-tf1, tf3)).doit() == TransferFunction(k*(a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2)**2 + \ + (-a2*p + s)*(s**2 + 2*s*wn*zeta + wn**2) + (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), (a2*s + p)*(s**2 + \ + 2*s*wn*zeta + wn**2)**2, s) + assert Parallel(tf2, tf1, -tf3, evaluate=True) == Parallel(tf2, tf1, -tf3).doit() == \ + TransferFunction(a2*s + k*(a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2) + p + (-a2*p + s)*(s**2 + 2*s*wn*zeta + wn**2) \ + , (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s) + assert not Parallel(tf1, -tf2, evaluate=False) == Parallel(tf1, -tf2).doit() + + assert Parallel(Series(tf1, tf2), Series(tf2, tf3)).doit() == \ + TransferFunction(k*(a2*p - s)*(s**2 + 2*s*wn*zeta + wn**2) + k*(a2*s + p), (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s) + assert Parallel(-tf1, -tf2, -tf3).doit() == \ + TransferFunction(-a2*s - k*(a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2) - p + (-a2*p + s)*(s**2 + 2*s*wn*zeta + wn**2), \ + (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s) + assert -Parallel(tf1, tf2, tf3).doit() == \ + TransferFunction(-a2*s - k*(a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2) - p - (a2*p - s)*(s**2 + 2*s*wn*zeta + wn**2), \ + (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s) + assert Parallel(tf2, tf3, Series(tf2, -tf1), tf3).doit() == \ + TransferFunction(k*(a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2) - k*(a2*s + p) + (2*a2*p - 2*s)*(s**2 + 2*s*wn*zeta \ + + wn**2), (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s) + + assert Parallel(tf1, tf2).rewrite(TransferFunction) == \ + TransferFunction(k*(s**2 + 2*s*wn*zeta + wn**2) + 1, s**2 + 2*s*wn*zeta + wn**2, s) + assert Parallel(tf2, tf1, -tf3).rewrite(TransferFunction) == \ + TransferFunction(a2*s + k*(a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2) + p + (-a2*p + s)*(s**2 + 2*s*wn*zeta + \ + wn**2), (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s) + + assert Parallel(tf1, Parallel(tf2, tf3)) == Parallel(tf1, tf2, tf3) == Parallel(Parallel(tf1, tf2), tf3) + + P1 = Parallel(Series(tf1, tf2), Series(tf2, tf3)) + assert P1.is_proper + assert not P1.is_strictly_proper + assert P1.is_biproper + + P2 = Parallel(tf1, -tf2, -tf3) + assert P2.is_proper + assert not P2.is_strictly_proper + assert P2.is_biproper + + P3 = Parallel(tf1, -tf2, Series(tf1, tf3)) + assert P3.is_proper + assert not P3.is_strictly_proper + assert P3.is_biproper + + +def test_MIMOParallel_functions(): + tf4 = TransferFunction(a0*p + p**a1 - s, p, p) + tf5 = TransferFunction(a1*s**2 + a2*s - a0, s + a0, s) + + tfm1 = TransferFunctionMatrix([[TF1], [TF2], [TF3]]) + tfm2 = TransferFunctionMatrix([[-TF2], [tf5], [-TF1]]) + tfm3 = TransferFunctionMatrix([[tf5], [-tf5], [TF2]]) + tfm4 = TransferFunctionMatrix([[TF2, -tf5], [TF1, tf5]]) + tfm5 = TransferFunctionMatrix([[TF1, TF2], [TF3, -tf5]]) + tfm6 = TransferFunctionMatrix([[-TF2]]) + tfm7 = TransferFunctionMatrix([[tf4], [-tf4], [tf4]]) + + assert tfm1 + tfm2 + tfm3 == MIMOParallel(tfm1, tfm2, tfm3) == MIMOParallel(MIMOParallel(tfm1, tfm2), tfm3) + assert tfm2 - tfm1 - tfm3 == MIMOParallel(tfm2, -tfm1, -tfm3) + assert tfm2 - tfm3 + (-tfm1*tfm6*-tfm6) == MIMOParallel(tfm2, -tfm3, MIMOSeries(-tfm6, tfm6, -tfm1)) + assert tfm1 + tfm1 - (-tfm1*tfm6) == MIMOParallel(tfm1, tfm1, -MIMOSeries(tfm6, -tfm1)) + assert tfm2 - tfm3 - tfm1 + tfm2 == MIMOParallel(tfm2, -tfm3, -tfm1, tfm2) + assert tfm1 + tfm2 - tfm3 - tfm1 == MIMOParallel(tfm1, tfm2, -tfm3, -tfm1) + raises(ValueError, lambda: tfm1 + tfm2 + TF2) + raises(TypeError, lambda: tfm1 - tfm2 - a1) + raises(TypeError, lambda: tfm2 - tfm3 - (s - 1)) + raises(TypeError, lambda: -tfm3 - tfm2 - 9) + raises(TypeError, lambda: (1 - p**3) - tfm3 - tfm2) + # All TFMs must use the same complex var. tfm7 uses 'p'. + raises(ValueError, lambda: tfm3 - tfm2 - tfm7) + raises(ValueError, lambda: tfm2 - tfm1 + tfm7) + # (tfm1 +/- tfm2) has (3, 1) shape while tfm4 has (2, 2) shape. + raises(TypeError, lambda: tfm1 + tfm2 + tfm4) + raises(TypeError, lambda: (tfm1 - tfm2) - tfm4) + + assert (tfm1 + tfm2)*tfm6 == MIMOSeries(tfm6, MIMOParallel(tfm1, tfm2)) + assert (tfm2 - tfm3)*tfm6*-tfm6 == MIMOSeries(-tfm6, tfm6, MIMOParallel(tfm2, -tfm3)) + assert (tfm2 - tfm1 - tfm3)*(tfm6 + tfm6) == MIMOSeries(MIMOParallel(tfm6, tfm6), MIMOParallel(tfm2, -tfm1, -tfm3)) + raises(ValueError, lambda: (tfm4 + tfm5)*TF1) + raises(TypeError, lambda: (tfm2 - tfm3)*a2) + raises(TypeError, lambda: (tfm3 + tfm2)*(s - 6)) + raises(TypeError, lambda: (tfm1 + tfm2 + tfm3)*0) + raises(TypeError, lambda: (1 - p**3)*(tfm1 + tfm3)) + + # (tfm3 - tfm2) has (3, 1) shape while tfm4*tfm5 has (2, 2) shape. + raises(ValueError, lambda: (tfm3 - tfm2)*tfm4*tfm5) + # (tfm1 - tfm2) has (3, 1) shape while tfm5 has (2, 2) shape. + raises(ValueError, lambda: (tfm1 - tfm2)*tfm5) + + # TFM in the arguments. + assert (MIMOParallel(tfm1, tfm2, evaluate=True) == MIMOParallel(tfm1, tfm2).doit() + == MIMOParallel(tfm1, tfm2).rewrite(TransferFunctionMatrix) + == TransferFunctionMatrix(((TransferFunction(-k*(s**2 + 2*s*wn*zeta + wn**2) + 1, s**2 + 2*s*wn*zeta + wn**2, s),), \ + (TransferFunction(-a0 + a1*s**2 + a2*s + k*(a0 + s), a0 + s, s),), (TransferFunction(-a2*s - p + (a2*p - s)* \ + (s**2 + 2*s*wn*zeta + wn**2), (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s),)))) + + +def test_Feedback_construction(): + tf1 = TransferFunction(1, s**2 + 2*zeta*wn*s + wn**2, s) + tf2 = TransferFunction(k, 1, s) + tf3 = TransferFunction(a2*p - s, a2*s + p, s) + tf4 = TransferFunction(a0*p + p**a1 - s, p, p) + tf5 = TransferFunction(a1*s**2 + a2*s - a0, s + a0, s) + tf6 = TransferFunction(s - p, p + s, p) + + f1 = Feedback(TransferFunction(1, 1, s), tf1*tf2*tf3) + assert f1.args == (TransferFunction(1, 1, s), Series(tf1, tf2, tf3), -1) + assert f1.sys1 == TransferFunction(1, 1, s) + assert f1.sys2 == Series(tf1, tf2, tf3) + assert f1.var == s + + f2 = Feedback(tf1, tf2*tf3) + assert f2.args == (tf1, Series(tf2, tf3), -1) + assert f2.sys1 == tf1 + assert f2.sys2 == Series(tf2, tf3) + assert f2.var == s + + f3 = Feedback(tf1*tf2, tf5) + assert f3.args == (Series(tf1, tf2), tf5, -1) + assert f3.sys1 == Series(tf1, tf2) + + f4 = Feedback(tf4, tf6) + assert f4.args == (tf4, tf6, -1) + assert f4.sys1 == tf4 + assert f4.var == p + + f5 = Feedback(tf5, TransferFunction(1, 1, s)) + assert f5.args == (tf5, TransferFunction(1, 1, s), -1) + assert f5.var == s + assert f5 == Feedback(tf5) # When sys2 is not passed explicitly, it is assumed to be unit tf. + + f6 = Feedback(TransferFunction(1, 1, p), tf4) + assert f6.args == (TransferFunction(1, 1, p), tf4, -1) + assert f6.var == p + + f7 = -Feedback(tf4*tf6, TransferFunction(1, 1, p)) + assert f7.args == (Series(TransferFunction(-1, 1, p), Series(tf4, tf6)), -TransferFunction(1, 1, p), -1) + assert f7.sys1 == Series(TransferFunction(-1, 1, p), Series(tf4, tf6)) + + # denominator can't be a Parallel instance + raises(TypeError, lambda: Feedback(tf1, tf2 + tf3)) + raises(TypeError, lambda: Feedback(tf1, Matrix([1, 2, 3]))) + raises(TypeError, lambda: Feedback(TransferFunction(1, 1, s), s - 1)) + raises(TypeError, lambda: Feedback(1, 1)) + # raises(ValueError, lambda: Feedback(TransferFunction(1, 1, s), TransferFunction(1, 1, s))) + raises(ValueError, lambda: Feedback(tf2, tf4*tf5)) + raises(ValueError, lambda: Feedback(tf2, tf1, 1.5)) # `sign` can only be -1 or 1 + raises(ValueError, lambda: Feedback(tf1, -tf1**-1)) # denominator can't be zero + raises(ValueError, lambda: Feedback(tf4, tf5)) # Both systems should use the same `var` + + +def test_Feedback_functions(): + tf = TransferFunction(1, 1, s) + tf1 = TransferFunction(1, s**2 + 2*zeta*wn*s + wn**2, s) + tf2 = TransferFunction(k, 1, s) + tf3 = TransferFunction(a2*p - s, a2*s + p, s) + tf4 = TransferFunction(a0*p + p**a1 - s, p, p) + tf5 = TransferFunction(a1*s**2 + a2*s - a0, s + a0, s) + tf6 = TransferFunction(s - p, p + s, p) + + assert (tf1*tf2*tf3 / tf3*tf5) == Series(tf1, tf2, tf3, pow(tf3, -1), tf5) + assert (tf1*tf2*tf3) / (tf3*tf5) == Series((tf1*tf2*tf3).doit(), pow((tf3*tf5).doit(),-1)) + assert tf / (tf + tf1) == Feedback(tf, tf1) + assert tf / (tf + tf1*tf2*tf3) == Feedback(tf, tf1*tf2*tf3) + assert tf1 / (tf + tf1*tf2*tf3) == Feedback(tf1, tf2*tf3) + assert (tf1*tf2) / (tf + tf1*tf2) == Feedback(tf1*tf2, tf) + assert (tf1*tf2) / (tf + tf1*tf2*tf5) == Feedback(tf1*tf2, tf5) + assert (tf1*tf2) / (tf + tf1*tf2*tf5*tf3) in (Feedback(tf1*tf2, tf5*tf3), Feedback(tf1*tf2, tf3*tf5)) + assert tf4 / (TransferFunction(1, 1, p) + tf4*tf6) == Feedback(tf4, tf6) + assert tf5 / (tf + tf5) == Feedback(tf5, tf) + + raises(TypeError, lambda: tf1*tf2*tf3 / (1 + tf1*tf2*tf3)) + raises(ValueError, lambda: tf2*tf3 / (tf + tf2*tf3*tf4)) + + assert Feedback(tf, tf1*tf2*tf3).doit() == \ + TransferFunction((a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), k*(a2*p - s) + \ + (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), s) + assert Feedback(tf, tf1*tf2*tf3).sensitivity == \ + 1/(k*(a2*p - s)/((a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2)) + 1) + assert Feedback(tf1, tf2*tf3).doit() == \ + TransferFunction((a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2), (k*(a2*p - s) + \ + (a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2))*(s**2 + 2*s*wn*zeta + wn**2), s) + assert Feedback(tf1, tf2*tf3).sensitivity == \ + 1/(k*(a2*p - s)/((a2*s + p)*(s**2 + 2*s*wn*zeta + wn**2)) + 1) + assert Feedback(tf1*tf2, tf5).doit() == \ + TransferFunction(k*(a0 + s)*(s**2 + 2*s*wn*zeta + wn**2), (k*(-a0 + a1*s**2 + a2*s) + \ + (a0 + s)*(s**2 + 2*s*wn*zeta + wn**2))*(s**2 + 2*s*wn*zeta + wn**2), s) + assert Feedback(tf1*tf2, tf5, 1).sensitivity == \ + 1/(-k*(-a0 + a1*s**2 + a2*s)/((a0 + s)*(s**2 + 2*s*wn*zeta + wn**2)) + 1) + assert Feedback(tf4, tf6).doit() == \ + TransferFunction(p*(p + s)*(a0*p + p**a1 - s), p*(p*(p + s) + (-p + s)*(a0*p + p**a1 - s)), p) + assert -Feedback(tf4*tf6, TransferFunction(1, 1, p)).doit() == \ + TransferFunction(-p*(-p + s)*(p + s)*(a0*p + p**a1 - s), p*(p + s)*(p*(p + s) + (-p + s)*(a0*p + p**a1 - s)), p) + assert Feedback(tf, tf).doit() == TransferFunction(1, 2, s) + + assert Feedback(tf1, tf2*tf5).rewrite(TransferFunction) == \ + TransferFunction((a0 + s)*(s**2 + 2*s*wn*zeta + wn**2), (k*(-a0 + a1*s**2 + a2*s) + \ + (a0 + s)*(s**2 + 2*s*wn*zeta + wn**2))*(s**2 + 2*s*wn*zeta + wn**2), s) + assert Feedback(TransferFunction(1, 1, p), tf4).rewrite(TransferFunction) == \ + TransferFunction(p, a0*p + p + p**a1 - s, p) + + +def test_Feedback_as_TransferFunction(): + # Solves issue https://github.com/sympy/sympy/issues/26161 + tf1 = TransferFunction(s+1, 1, s) + tf2 = TransferFunction(s+2, 1, s) + fd1 = Feedback(tf1, tf2, -1) # Negative Feedback system + fd2 = Feedback(tf1, tf2, 1) # Positive Feedback system + unit = TransferFunction(1, 1, s) + + # Checking the type + assert isinstance(fd1, TransferFunction) + assert isinstance(fd1, Feedback) + + # Testing the numerator and denominator + assert fd1.num == tf1 + assert fd2.num == tf1 + assert fd1.den == Parallel(unit, Series(tf2, tf1)) + assert fd2.den == Parallel(unit, -Series(tf2, tf1)) + + # Testing the Series and Parallel Combination with Feedback and TransferFunction + s1 = Series(tf1, fd1) + p1 = Parallel(tf1, fd1) + assert tf1 * fd1 == s1 + assert tf1 + fd1 == p1 + assert s1.doit() == TransferFunction((s + 1)**2, (s + 1)*(s + 2) + 1, s) + assert p1.doit() == TransferFunction(s + (s + 1)*((s + 1)*(s + 2) + 1) + 1, (s + 1)*(s + 2) + 1, s) + + # Testing the use of Feedback and TransferFunction with Feedback + fd3 = Feedback(tf1*fd1, tf2, -1) + assert fd3 == Feedback(Series(tf1, fd1), tf2) + assert fd3.num == tf1 * fd1 + assert fd3.den == Parallel(unit, Series(tf2, Series(tf1, fd1))) + + # Testing the use of Feedback and TransferFunction with TransferFunction + tf3 = TransferFunction(tf1*fd1, tf2, s) + assert tf3 == TransferFunction(Series(tf1, fd1), tf2, s) + assert tf3.num == tf1*fd1 + +def test_issue_26161(): + # Issue https://github.com/sympy/sympy/issues/26161 + Ib, Is, m, h, l2, l1 = symbols('I_b, I_s, m, h, l2, l1', + real=True, nonnegative=True) + KD, KP, v = symbols('K_D, K_P, v', real=True) + + tau1_sq = (Ib + m * h ** 2) / m / g / h + tau2 = l2 / v + tau3 = v / (l1 + l2) + K = v ** 2 / g / (l1 + l2) + + Gtheta = TransferFunction(-K * (tau2 * s + 1), tau1_sq * s ** 2 - 1, s) + Gdelta = TransferFunction(1, Is * s ** 2 + c * s, s) + Gpsi = TransferFunction(1, tau3 * s, s) + Dcont = TransferFunction(KD * s, 1, s) + PIcont = TransferFunction(KP, s, s) + Gunity = TransferFunction(1, 1, s) + + Ginner = Feedback(Dcont * Gdelta, Gtheta) + Gouter = Feedback(PIcont * Ginner * Gpsi, Gunity) + assert Gouter == Feedback(Series(PIcont, Series(Ginner, Gpsi)), Gunity) + assert Gouter.num == Series(PIcont, Series(Ginner, Gpsi)) + assert Gouter.den == Parallel(Gunity, Series(Gunity, Series(PIcont, Series(Ginner, Gpsi)))) + expr = (KD*KP*g*s**3*v**2*(l1 + l2)*(Is*s**2 + c*s)**2*(-g*h*m + s**2*(Ib + h**2*m))*(-KD*g*h*m*s*v**2*(l2*s + v) + \ + g*v*(l1 + l2)*(Is*s**2 + c*s)*(-g*h*m + s**2*(Ib + h**2*m))))/((s**2*v*(Is*s**2 + c*s)*(-KD*g*h*m*s*v**2* \ + (l2*s + v) + g*v*(l1 + l2)*(Is*s**2 + c*s)*(-g*h*m + s**2*(Ib + h**2*m)))*(KD*KP*g*s*v*(l1 + l2)**2* \ + (Is*s**2 + c*s)*(-g*h*m + s**2*(Ib + h**2*m)) + s**2*v*(Is*s**2 + c*s)*(-KD*g*h*m*s*v**2*(l2*s + v) + \ + g*v*(l1 + l2)*(Is*s**2 + c*s)*(-g*h*m + s**2*(Ib + h**2*m))))/(l1 + l2))) + + assert (Gouter.to_expr() - expr).simplify() == 0 + + +def test_MIMOFeedback_construction(): + tf1 = TransferFunction(1, s, s) + tf2 = TransferFunction(s, s**3 - 1, s) + tf3 = TransferFunction(s, s + 1, s) + tf4 = TransferFunction(s, s**2 + 1, s) + + tfm_1 = TransferFunctionMatrix([[tf1, tf2], [tf3, tf4]]) + tfm_2 = TransferFunctionMatrix([[tf2, tf3], [tf4, tf1]]) + tfm_3 = TransferFunctionMatrix([[tf3, tf4], [tf1, tf2]]) + + f1 = MIMOFeedback(tfm_1, tfm_2) + assert f1.args == (tfm_1, tfm_2, -1) + assert f1.sys1 == tfm_1 + assert f1.sys2 == tfm_2 + assert f1.var == s + assert f1.sign == -1 + assert -(-f1) == f1 + + f2 = MIMOFeedback(tfm_2, tfm_1, 1) + assert f2.args == (tfm_2, tfm_1, 1) + assert f2.sys1 == tfm_2 + assert f2.sys2 == tfm_1 + assert f2.var == s + assert f2.sign == 1 + + f3 = MIMOFeedback(tfm_1, MIMOSeries(tfm_3, tfm_2)) + assert f3.args == (tfm_1, MIMOSeries(tfm_3, tfm_2), -1) + assert f3.sys1 == tfm_1 + assert f3.sys2 == MIMOSeries(tfm_3, tfm_2) + assert f3.var == s + assert f3.sign == -1 + + mat = Matrix([[1, 1/s], [0, 1]]) + sys1 = controller = TransferFunctionMatrix.from_Matrix(mat, s) + f4 = MIMOFeedback(sys1, controller) + assert f4.args == (sys1, controller, -1) + assert f4.sys1 == f4.sys2 == sys1 + + +def test_MIMOFeedback_errors(): + tf1 = TransferFunction(1, s, s) + tf2 = TransferFunction(s, s**3 - 1, s) + tf3 = TransferFunction(s, s - 1, s) + tf4 = TransferFunction(s, s**2 + 1, s) + tf5 = TransferFunction(1, 1, s) + tf6 = TransferFunction(-1, s - 1, s) + + tfm_1 = TransferFunctionMatrix([[tf1, tf2], [tf3, tf4]]) + tfm_2 = TransferFunctionMatrix([[tf2, tf3], [tf4, tf1]]) + tfm_3 = TransferFunctionMatrix.from_Matrix(eye(2), var=s) + tfm_4 = TransferFunctionMatrix([[tf1, tf5], [tf5, tf5]]) + tfm_5 = TransferFunctionMatrix([[-tf3, tf3], [tf3, tf6]]) + # tfm_4 is inverse of tfm_5. Therefore tfm_5*tfm_4 = I + tfm_6 = TransferFunctionMatrix([[-tf3]]) + tfm_7 = TransferFunctionMatrix([[tf3, tf4]]) + + # Unsupported Types + raises(TypeError, lambda: MIMOFeedback(tf1, tf2)) + raises(TypeError, lambda: MIMOFeedback(MIMOParallel(tfm_1, tfm_2), tfm_3)) + # Shape Errors + raises(ValueError, lambda: MIMOFeedback(tfm_1, tfm_6, 1)) + raises(ValueError, lambda: MIMOFeedback(tfm_7, tfm_7)) + # sign not 1/-1 + raises(ValueError, lambda: MIMOFeedback(tfm_1, tfm_2, -2)) + # Non-Invertible Systems + raises(ValueError, lambda: MIMOFeedback(tfm_5, tfm_4, 1)) + raises(ValueError, lambda: MIMOFeedback(tfm_4, -tfm_5)) + raises(ValueError, lambda: MIMOFeedback(tfm_3, tfm_3, 1)) + # Variable not same in both the systems + tfm_8 = TransferFunctionMatrix.from_Matrix(eye(2), var=p) + raises(ValueError, lambda: MIMOFeedback(tfm_1, tfm_8, 1)) + + +def test_MIMOFeedback_functions(): + tf1 = TransferFunction(1, s, s) + tf2 = TransferFunction(s, s - 1, s) + tf3 = TransferFunction(1, 1, s) + tf4 = TransferFunction(-1, s - 1, s) + + tfm_1 = TransferFunctionMatrix.from_Matrix(eye(2), var=s) + tfm_2 = TransferFunctionMatrix([[tf1, tf3], [tf3, tf3]]) + tfm_3 = TransferFunctionMatrix([[-tf2, tf2], [tf2, tf4]]) + tfm_4 = TransferFunctionMatrix([[tf1, tf2], [-tf2, tf1]]) + + # sensitivity, doit(), rewrite() + F_1 = MIMOFeedback(tfm_2, tfm_3) + F_2 = MIMOFeedback(tfm_2, MIMOSeries(tfm_4, -tfm_1), 1) + + assert F_1.sensitivity == Matrix([[S.Half, 0], [0, S.Half]]) + assert F_2.sensitivity == Matrix([[(-2*s**4 + s**2)/(s**2 - s + 1), + (2*s**3 - s**2)/(s**2 - s + 1)], [-s**2, s]]) + + assert F_1.doit() == \ + TransferFunctionMatrix(((TransferFunction(1, 2*s, s), + TransferFunction(1, 2, s)), (TransferFunction(1, 2, s), + TransferFunction(1, 2, s)))) == F_1.rewrite(TransferFunctionMatrix) + assert F_2.doit(cancel=False, expand=True) == \ + TransferFunctionMatrix(((TransferFunction(-s**5 + 2*s**4 - 2*s**3 + s**2, s**5 - 2*s**4 + 3*s**3 - 2*s**2 + s, s), + TransferFunction(-2*s**4 + 2*s**3, s**2 - s + 1, s)), (TransferFunction(0, 1, s), TransferFunction(-s**2 + s, 1, s)))) + assert F_2.doit(cancel=False) == \ + TransferFunctionMatrix(((TransferFunction(s*(2*s**3 - s**2)*(s**2 - s + 1) + \ + (-2*s**4 + s**2)*(s**2 - s + 1), s*(s**2 - s + 1)**2, s), TransferFunction(-2*s**4 + 2*s**3, s**2 - s + 1, s)), + (TransferFunction(0, 1, s), TransferFunction(-s**2 + s, 1, s)))) + assert F_2.doit() == \ + TransferFunctionMatrix(((TransferFunction(s*(-2*s**2 + s*(2*s - 1) + 1), s**2 - s + 1, s), + TransferFunction(-2*s**3*(s - 1), s**2 - s + 1, s)), (TransferFunction(0, 1, s), TransferFunction(s*(1 - s), 1, s)))) + assert F_2.doit(expand=True) == \ + TransferFunctionMatrix(((TransferFunction(-s**2 + s, s**2 - s + 1, s), TransferFunction(-2*s**4 + 2*s**3, s**2 - s + 1, s)), + (TransferFunction(0, 1, s), TransferFunction(-s**2 + s, 1, s)))) + + assert -(F_1.doit()) == (-F_1).doit() # First negating then calculating vs calculating then negating. + + +def test_TransferFunctionMatrix_construction(): + tf5 = TransferFunction(a1*s**2 + a2*s - a0, s + a0, s) + tf4 = TransferFunction(a0*p + p**a1 - s, p, p) + + tfm3_ = TransferFunctionMatrix([[-TF3]]) + assert tfm3_.shape == (tfm3_.num_outputs, tfm3_.num_inputs) == (1, 1) + assert tfm3_.args == Tuple(Tuple(Tuple(-TF3))) + assert tfm3_.var == s + + tfm5 = TransferFunctionMatrix([[TF1, -TF2], [TF3, tf5]]) + assert tfm5.shape == (tfm5.num_outputs, tfm5.num_inputs) == (2, 2) + assert tfm5.args == Tuple(Tuple(Tuple(TF1, -TF2), Tuple(TF3, tf5))) + assert tfm5.var == s + + tfm7 = TransferFunctionMatrix([[TF1, TF2], [TF3, -tf5], [-tf5, TF2]]) + assert tfm7.shape == (tfm7.num_outputs, tfm7.num_inputs) == (3, 2) + assert tfm7.args == Tuple(Tuple(Tuple(TF1, TF2), Tuple(TF3, -tf5), Tuple(-tf5, TF2))) + assert tfm7.var == s + + # all transfer functions will use the same complex variable. tf4 uses 'p'. + raises(ValueError, lambda: TransferFunctionMatrix([[TF1], [TF2], [tf4]])) + raises(ValueError, lambda: TransferFunctionMatrix([[TF1, tf4], [TF3, tf5]])) + + # length of all the lists in the TFM should be equal. + raises(ValueError, lambda: TransferFunctionMatrix([[TF1], [TF3, tf5]])) + raises(ValueError, lambda: TransferFunctionMatrix([[TF1, TF3], [tf5]])) + + # lists should only support transfer functions in them. + raises(TypeError, lambda: TransferFunctionMatrix([[TF1, TF2], [TF3, Matrix([1, 2])]])) + raises(TypeError, lambda: TransferFunctionMatrix([[TF1, Matrix([1, 2])], [TF3, TF2]])) + + # `arg` should strictly be nested list of TransferFunction + raises(ValueError, lambda: TransferFunctionMatrix([TF1, TF2, tf5])) + raises(ValueError, lambda: TransferFunctionMatrix([TF1])) + +def test_TransferFunctionMatrix_functions(): + tf5 = TransferFunction(a1*s**2 + a2*s - a0, s + a0, s) + + # Classmethod (from_matrix) + + mat_1 = ImmutableMatrix([ + [s*(s + 1)*(s - 3)/(s**4 + 1), 2], + [p, p*(s + 1)/(s*(s**1 + 1))] + ]) + mat_2 = ImmutableMatrix([[(2*s + 1)/(s**2 - 9)]]) + mat_3 = ImmutableMatrix([[1, 2], [3, 4]]) + assert TransferFunctionMatrix.from_Matrix(mat_1, s) == \ + TransferFunctionMatrix([[TransferFunction(s*(s - 3)*(s + 1), s**4 + 1, s), TransferFunction(2, 1, s)], + [TransferFunction(p, 1, s), TransferFunction(p, s, s)]]) + assert TransferFunctionMatrix.from_Matrix(mat_2, s) == \ + TransferFunctionMatrix([[TransferFunction(2*s + 1, s**2 - 9, s)]]) + assert TransferFunctionMatrix.from_Matrix(mat_3, p) == \ + TransferFunctionMatrix([[TransferFunction(1, 1, p), TransferFunction(2, 1, p)], + [TransferFunction(3, 1, p), TransferFunction(4, 1, p)]]) + + # Negating a TFM + + tfm1 = TransferFunctionMatrix([[TF1], [TF2]]) + assert -tfm1 == TransferFunctionMatrix([[-TF1], [-TF2]]) + + tfm2 = TransferFunctionMatrix([[TF1, TF2, TF3], [tf5, -TF1, -TF3]]) + assert -tfm2 == TransferFunctionMatrix([[-TF1, -TF2, -TF3], [-tf5, TF1, TF3]]) + + # subs() + + H_1 = TransferFunctionMatrix.from_Matrix(mat_1, s) + H_2 = TransferFunctionMatrix([[TransferFunction(a*p*s, k*s**2, s), TransferFunction(p*s, k*(s**2 - a), s)]]) + assert H_1.subs(p, 1) == TransferFunctionMatrix([[TransferFunction(s*(s - 3)*(s + 1), s**4 + 1, s), TransferFunction(2, 1, s)], [TransferFunction(1, 1, s), TransferFunction(1, s, s)]]) + assert H_1.subs({p: 1}) == TransferFunctionMatrix([[TransferFunction(s*(s - 3)*(s + 1), s**4 + 1, s), TransferFunction(2, 1, s)], [TransferFunction(1, 1, s), TransferFunction(1, s, s)]]) + assert H_1.subs({p: 1, s: 1}) == TransferFunctionMatrix([[TransferFunction(s*(s - 3)*(s + 1), s**4 + 1, s), TransferFunction(2, 1, s)], [TransferFunction(1, 1, s), TransferFunction(1, s, s)]]) # This should ignore `s` as it is `var` + assert H_2.subs(p, 2) == TransferFunctionMatrix([[TransferFunction(2*a*s, k*s**2, s), TransferFunction(2*s, k*(-a + s**2), s)]]) + assert H_2.subs(k, 1) == TransferFunctionMatrix([[TransferFunction(a*p*s, s**2, s), TransferFunction(p*s, -a + s**2, s)]]) + assert H_2.subs(a, 0) == TransferFunctionMatrix([[TransferFunction(0, k*s**2, s), TransferFunction(p*s, k*s**2, s)]]) + assert H_2.subs({p: 1, k: 1, a: a0}) == TransferFunctionMatrix([[TransferFunction(a0*s, s**2, s), TransferFunction(s, -a0 + s**2, s)]]) + + # eval_frequency() + assert H_2.eval_frequency(S(1)/2 + I) == Matrix([[2*a*p/(5*k) - 4*I*a*p/(5*k), I*p/(-a*k - 3*k/4 + I*k) + p/(-2*a*k - 3*k/2 + 2*I*k)]]) + + # transpose() + + assert H_1.transpose() == TransferFunctionMatrix([[TransferFunction(s*(s - 3)*(s + 1), s**4 + 1, s), TransferFunction(p, 1, s)], [TransferFunction(2, 1, s), TransferFunction(p, s, s)]]) + assert H_2.transpose() == TransferFunctionMatrix([[TransferFunction(a*p*s, k*s**2, s)], [TransferFunction(p*s, k*(-a + s**2), s)]]) + assert H_1.transpose().transpose() == H_1 + assert H_2.transpose().transpose() == H_2 + + # elem_poles() + + assert H_1.elem_poles() == [[[-sqrt(2)/2 - sqrt(2)*I/2, -sqrt(2)/2 + sqrt(2)*I/2, sqrt(2)/2 - sqrt(2)*I/2, sqrt(2)/2 + sqrt(2)*I/2], []], + [[], [0]]] + assert H_2.elem_poles() == [[[0, 0], [sqrt(a), -sqrt(a)]]] + assert tfm2.elem_poles() == [[[wn*(-zeta + sqrt((zeta - 1)*(zeta + 1))), wn*(-zeta - sqrt((zeta - 1)*(zeta + 1)))], [], [-p/a2]], + [[-a0], [wn*(-zeta + sqrt((zeta - 1)*(zeta + 1))), wn*(-zeta - sqrt((zeta - 1)*(zeta + 1)))], [-p/a2]]] + + # elem_zeros() + + assert H_1.elem_zeros() == [[[-1, 0, 3], []], [[], []]] + assert H_2.elem_zeros() == [[[0], [0]]] + assert tfm2.elem_zeros() == [[[], [], [a2*p]], + [[-a2/(2*a1) - sqrt(4*a0*a1 + a2**2)/(2*a1), -a2/(2*a1) + sqrt(4*a0*a1 + a2**2)/(2*a1)], [], [a2*p]]] + + # doit() + + H_3 = TransferFunctionMatrix([[Series(TransferFunction(1, s**3 - 3, s), TransferFunction(s**2 - 2*s + 5, 1, s), TransferFunction(1, s, s))]]) + H_4 = TransferFunctionMatrix([[Parallel(TransferFunction(s**3 - 3, 4*s**4 - s**2 - 2*s + 5, s), TransferFunction(4 - s**3, 4*s**4 - s**2 - 2*s + 5, s))]]) + + assert H_3.doit() == TransferFunctionMatrix([[TransferFunction(s**2 - 2*s + 5, s*(s**3 - 3), s)]]) + assert H_4.doit() == TransferFunctionMatrix([[TransferFunction(1, 4*s**4 - s**2 - 2*s + 5, s)]]) + + # _flat() + + assert H_1._flat() == [TransferFunction(s*(s - 3)*(s + 1), s**4 + 1, s), TransferFunction(2, 1, s), TransferFunction(p, 1, s), TransferFunction(p, s, s)] + assert H_2._flat() == [TransferFunction(a*p*s, k*s**2, s), TransferFunction(p*s, k*(-a + s**2), s)] + assert H_3._flat() == [Series(TransferFunction(1, s**3 - 3, s), TransferFunction(s**2 - 2*s + 5, 1, s), TransferFunction(1, s, s))] + assert H_4._flat() == [Parallel(TransferFunction(s**3 - 3, 4*s**4 - s**2 - 2*s + 5, s), TransferFunction(4 - s**3, 4*s**4 - s**2 - 2*s + 5, s))] + + # evalf() + + assert H_1.evalf() == \ + TransferFunctionMatrix(((TransferFunction(s*(s - 3.0)*(s + 1.0), s**4 + 1.0, s), TransferFunction(2.0, 1, s)), (TransferFunction(1.0*p, 1, s), TransferFunction(p, s, s)))) + assert H_2.subs({a:3.141, p:2.88, k:2}).evalf() == \ + TransferFunctionMatrix(((TransferFunction(4.5230399999999999494093572138808667659759521484375, s, s), + TransferFunction(2.87999999999999989341858963598497211933135986328125*s, 2.0*s**2 - 6.282000000000000028421709430404007434844970703125, s)),)) + + # simplify() + + H_5 = TransferFunctionMatrix([[TransferFunction(s**5 + s**3 + s, s - s**2, s), + TransferFunction((s + 3)*(s - 1), (s - 1)*(s + 5), s)]]) + + assert H_5.simplify() == simplify(H_5) == \ + TransferFunctionMatrix(((TransferFunction(-s**4 - s**2 - 1, s - 1, s), TransferFunction(s + 3, s + 5, s)),)) + + # expand() + + assert (H_1.expand() + == TransferFunctionMatrix(((TransferFunction(s**3 - 2*s**2 - 3*s, s**4 + 1, s), TransferFunction(2, 1, s)), + (TransferFunction(p, 1, s), TransferFunction(p, s, s))))) + assert H_5.expand() == \ + TransferFunctionMatrix(((TransferFunction(s**5 + s**3 + s, -s**2 + s, s), TransferFunction(s**2 + 2*s - 3, s**2 + 4*s - 5, s)),)) + +def test_TransferFunction_gbt(): + # simple transfer function, e.g. ohms law + tf = TransferFunction(1, a*s+b, s) + numZ, denZ = gbt(tf, T, 0.5) + # discretized transfer function with coefs from tf.gbt() + tf_test_bilinear = TransferFunction(s * numZ[0] + numZ[1], s * denZ[0] + denZ[1], s) + # corresponding tf with manually calculated coefs + tf_test_manual = TransferFunction(s * T/(2*(a + b*T/2)) + T/(2*(a + b*T/2)), s + (-a + b*T/2)/(a + b*T/2), s) + + assert S.Zero == (tf_test_bilinear.simplify()-tf_test_manual.simplify()).simplify().num + + tf = TransferFunction(1, a*s+b, s) + numZ, denZ = gbt(tf, T, 0) + # discretized transfer function with coefs from tf.gbt() + tf_test_forward = TransferFunction(numZ[0], s*denZ[0]+denZ[1], s) + # corresponding tf with manually calculated coefs + tf_test_manual = TransferFunction(T/a, s + (-a + b*T)/a, s) + + assert S.Zero == (tf_test_forward.simplify()-tf_test_manual.simplify()).simplify().num + + tf = TransferFunction(1, a*s+b, s) + numZ, denZ = gbt(tf, T, 1) + # discretized transfer function with coefs from tf.gbt() + tf_test_backward = TransferFunction(s*numZ[0], s*denZ[0]+denZ[1], s) + # corresponding tf with manually calculated coefs + tf_test_manual = TransferFunction(s * T/(a + b*T), s - a/(a + b*T), s) + + assert S.Zero == (tf_test_backward.simplify()-tf_test_manual.simplify()).simplify().num + + tf = TransferFunction(1, a*s+b, s) + numZ, denZ = gbt(tf, T, 0.3) + # discretized transfer function with coefs from tf.gbt() + tf_test_gbt = TransferFunction(s*numZ[0]+numZ[1], s*denZ[0]+denZ[1], s) + # corresponding tf with manually calculated coefs + tf_test_manual = TransferFunction(s*3*T/(10*(a + 3*b*T/10)) + 7*T/(10*(a + 3*b*T/10)), s + (-a + 7*b*T/10)/(a + 3*b*T/10), s) + + assert S.Zero == (tf_test_gbt.simplify()-tf_test_manual.simplify()).simplify().num + +def test_TransferFunction_bilinear(): + # simple transfer function, e.g. ohms law + tf = TransferFunction(1, a*s+b, s) + numZ, denZ = bilinear(tf, T) + # discretized transfer function with coefs from tf.bilinear() + tf_test_bilinear = TransferFunction(s*numZ[0]+numZ[1], s*denZ[0]+denZ[1], s) + # corresponding tf with manually calculated coefs + tf_test_manual = TransferFunction(s * T/(2*(a + b*T/2)) + T/(2*(a + b*T/2)), s + (-a + b*T/2)/(a + b*T/2), s) + + assert S.Zero == (tf_test_bilinear.simplify()-tf_test_manual.simplify()).simplify().num + +def test_TransferFunction_forward_diff(): + # simple transfer function, e.g. ohms law + tf = TransferFunction(1, a*s+b, s) + numZ, denZ = forward_diff(tf, T) + # discretized transfer function with coefs from tf.forward_diff() + tf_test_forward = TransferFunction(numZ[0], s*denZ[0]+denZ[1], s) + # corresponding tf with manually calculated coefs + tf_test_manual = TransferFunction(T/a, s + (-a + b*T)/a, s) + + assert S.Zero == (tf_test_forward.simplify()-tf_test_manual.simplify()).simplify().num + +def test_TransferFunction_backward_diff(): + # simple transfer function, e.g. ohms law + tf = TransferFunction(1, a*s+b, s) + numZ, denZ = backward_diff(tf, T) + # discretized transfer function with coefs from tf.backward_diff() + tf_test_backward = TransferFunction(s*numZ[0]+numZ[1], s*denZ[0]+denZ[1], s) + # corresponding tf with manually calculated coefs + tf_test_manual = TransferFunction(s * T/(a + b*T), s - a/(a + b*T), s) + + assert S.Zero == (tf_test_backward.simplify()-tf_test_manual.simplify()).simplify().num + +def test_TransferFunction_phase_margin(): + # Test for phase margin + tf1 = TransferFunction(10, p**3 + 1, p) + tf2 = TransferFunction(s**2, 10, s) + tf3 = TransferFunction(1, a*s+b, s) + tf4 = TransferFunction((s + 1)*exp(s/tau), s**2 + 2, s) + tf_m = TransferFunctionMatrix([[tf2],[tf3]]) + + assert phase_margin(tf1) == -180 + 180*atan(3*sqrt(11))/pi + assert phase_margin(tf2) == 0 + + raises(NotImplementedError, lambda: phase_margin(tf4)) + raises(ValueError, lambda: phase_margin(tf3)) + raises(ValueError, lambda: phase_margin(MIMOSeries(tf_m))) + +def test_TransferFunction_gain_margin(): + # Test for gain margin + tf1 = TransferFunction(s**2, 5*(s+1)*(s-5)*(s-10), s) + tf2 = TransferFunction(s**2 + 2*s + 1, 1, s) + tf3 = TransferFunction(1, a*s+b, s) + tf4 = TransferFunction((s + 1)*exp(s/tau), s**2 + 2, s) + tf_m = TransferFunctionMatrix([[tf2],[tf3]]) + + assert gain_margin(tf1) == -20*log(S(7)/540)/log(10) + assert gain_margin(tf2) == oo + + raises(NotImplementedError, lambda: gain_margin(tf4)) + raises(ValueError, lambda: gain_margin(tf3)) + raises(ValueError, lambda: gain_margin(MIMOSeries(tf_m))) + + +def test_StateSpace_construction(): + # using different numbers for a SISO system. + A1 = Matrix([[0, 1], [1, 0]]) + B1 = Matrix([1, 0]) + C1 = Matrix([[0, 1]]) + D1 = Matrix([0]) + ss1 = StateSpace(A1, B1, C1, D1) + + assert ss1.state_matrix == Matrix([[0, 1], [1, 0]]) + assert ss1.input_matrix == Matrix([1, 0]) + assert ss1.output_matrix == Matrix([[0, 1]]) + assert ss1.feedforward_matrix == Matrix([0]) + assert ss1.args == (Matrix([[0, 1], [1, 0]]), Matrix([[1], [0]]), Matrix([[0, 1]]), Matrix([[0]])) + + # using different symbols for a SISO system. + ss2 = StateSpace(Matrix([a0]), Matrix([a1]), + Matrix([a2]), Matrix([a3])) + + assert ss2.state_matrix == Matrix([[a0]]) + assert ss2.input_matrix == Matrix([[a1]]) + assert ss2.output_matrix == Matrix([[a2]]) + assert ss2.feedforward_matrix == Matrix([[a3]]) + assert ss2.args == (Matrix([[a0]]), Matrix([[a1]]), Matrix([[a2]]), Matrix([[a3]])) + + # using different numbers for a MIMO system. + ss3 = StateSpace(Matrix([[-1.5, -2], [1, 0]]), + Matrix([[0.5, 0], [0, 1]]), + Matrix([[0, 1], [0, 2]]), + Matrix([[2, 2], [1, 1]])) + + assert ss3.state_matrix == Matrix([[-1.5, -2], [1, 0]]) + assert ss3.input_matrix == Matrix([[0.5, 0], [0, 1]]) + assert ss3.output_matrix == Matrix([[0, 1], [0, 2]]) + assert ss3.feedforward_matrix == Matrix([[2, 2], [1, 1]]) + assert ss3.args == (Matrix([[-1.5, -2], + [1, 0]]), + Matrix([[0.5, 0], + [0, 1]]), + Matrix([[0, 1], + [0, 2]]), + Matrix([[2, 2], + [1, 1]])) + + # using different symbols for a MIMO system. + A4 = Matrix([[a0, a1], [a2, a3]]) + B4 = Matrix([[b0, b1], [b2, b3]]) + C4 = Matrix([[c0, c1], [c2, c3]]) + D4 = Matrix([[d0, d1], [d2, d3]]) + ss4 = StateSpace(A4, B4, C4, D4) + + assert ss4.state_matrix == Matrix([[a0, a1], [a2, a3]]) + assert ss4.input_matrix == Matrix([[b0, b1], [b2, b3]]) + assert ss4.output_matrix == Matrix([[c0, c1], [c2, c3]]) + assert ss4.feedforward_matrix == Matrix([[d0, d1], [d2, d3]]) + assert ss4.args == (Matrix([[a0, a1], + [a2, a3]]), + Matrix([[b0, b1], + [b2, b3]]), + Matrix([[c0, c1], + [c2, c3]]), + Matrix([[d0, d1], + [d2, d3]])) + + # using less matrices. Rest will be filled with a minimum of zeros. + ss5 = StateSpace() + assert ss5.args == (Matrix([[0]]), Matrix([[0]]), Matrix([[0]]), Matrix([[0]])) + + A6 = Matrix([[0, 1], [1, 0]]) + B6 = Matrix([1, 1]) + ss6 = StateSpace(A6, B6) + + assert ss6.state_matrix == Matrix([[0, 1], [1, 0]]) + assert ss6.input_matrix == Matrix([1, 1]) + assert ss6.output_matrix == Matrix([[0, 0]]) + assert ss6.feedforward_matrix == Matrix([[0]]) + assert ss6.args == (Matrix([[0, 1], + [1, 0]]), + Matrix([[1], + [1]]), + Matrix([[0, 0]]), + Matrix([[0]])) + + # Check if the system is SISO or MIMO. + # If system is not SISO, then it is definitely MIMO. + + assert ss1.is_SISO == True + assert ss2.is_SISO == True + assert ss3.is_SISO == False + assert ss4.is_SISO == False + assert ss5.is_SISO == True + assert ss6.is_SISO == True + + # ShapeError if matrices do not fit. + raises(ShapeError, lambda: StateSpace(Matrix([s, (s+1)**2]), Matrix([s+1]), + Matrix([s**2 - 1]), Matrix([2*s]))) + raises(ShapeError, lambda: StateSpace(Matrix([s]), Matrix([s+1, s**3 + 1]), + Matrix([s**2 - 1]), Matrix([2*s]))) + raises(ShapeError, lambda: StateSpace(Matrix([s]), Matrix([s+1]), + Matrix([[s**2 - 1], [s**2 + 2*s + 1]]), Matrix([2*s]))) + raises(ShapeError, lambda: StateSpace(Matrix([[-s, -s], [s, 0]]), + Matrix([[s/2, 0], [0, s]]), + Matrix([[0, s]]), + Matrix([[2*s, 2*s], [s, s]]))) + + # TypeError if arguments are not sympy matrices. + raises(TypeError, lambda: StateSpace(s**2, s+1, 2*s, 1)) + raises(TypeError, lambda: StateSpace(Matrix([2, 0.5]), Matrix([-1]), + Matrix([1]), 0)) +def test_StateSpace_add(): + A1 = Matrix([[4, 1],[2, -3]]) + B1 = Matrix([[5, 2],[-3, -3]]) + C1 = Matrix([[2, -4],[0, 1]]) + D1 = Matrix([[3, 2],[1, -1]]) + ss1 = StateSpace(A1, B1, C1, D1) + + A2 = Matrix([[-3, 4, 2],[-1, -3, 0],[2, 5, 3]]) + B2 = Matrix([[1, 4],[-3, -3],[-2, 1]]) + C2 = Matrix([[4, 2, -3],[1, 4, 3]]) + D2 = Matrix([[-2, 4],[0, 1]]) + ss2 = StateSpace(A2, B2, C2, D2) + ss3 = StateSpace() + ss4 = StateSpace(Matrix([1]), Matrix([2]), Matrix([3]), Matrix([4])) + + expected_add = \ + StateSpace( + Matrix([ + [4, 1, 0, 0, 0], + [2, -3, 0, 0, 0], + [0, 0, -3, 4, 2], + [0, 0, -1, -3, 0], + [0, 0, 2, 5, 3]]), + Matrix([ + [ 5, 2], + [-3, -3], + [ 1, 4], + [-3, -3], + [-2, 1]]), + Matrix([ + [2, -4, 4, 2, -3], + [0, 1, 1, 4, 3]]), + Matrix([ + [1, 6], + [1, 0]])) + + expected_mul = \ + StateSpace( + Matrix([ + [ -3, 4, 2, 0, 0], + [ -1, -3, 0, 0, 0], + [ 2, 5, 3, 0, 0], + [ 22, 18, -9, 4, 1], + [-15, -18, 0, 2, -3]]), + Matrix([ + [ 1, 4], + [ -3, -3], + [ -2, 1], + [-10, 22], + [ 6, -15]]), + Matrix([ + [14, 14, -3, 2, -4], + [ 3, -2, -6, 0, 1]]), + Matrix([ + [-6, 14], + [-2, 3]])) + + assert ss1 + ss2 == expected_add + assert ss1*ss2 == expected_mul + assert ss3 + 1/2 == StateSpace(Matrix([[0]]), Matrix([[0]]), Matrix([[0]]), Matrix([[0.5]])) + assert ss4*1.5 == StateSpace(Matrix([[1]]), Matrix([[2]]), Matrix([[4.5]]), Matrix([[6.0]])) + assert 1.5*ss4 == StateSpace(Matrix([[1]]), Matrix([[3.0]]), Matrix([[3]]), Matrix([[6.0]])) + raises(ShapeError, lambda: ss1 + ss3) + raises(ShapeError, lambda: ss2*ss4) + +def test_StateSpace_negation(): + A = Matrix([[a0, a1], [a2, a3]]) + B = Matrix([[b0, b1], [b2, b3]]) + C = Matrix([[c0, c1], [c1, c2], [c2, c3]]) + D = Matrix([[d0, d1], [d1, d2], [d2, d3]]) + SS = StateSpace(A, B, C, D) + SS_neg = -SS + + state_mat = Matrix([[-1, 1], [1, -1]]) + input_mat = Matrix([1, -1]) + output_mat = Matrix([[-1, 1]]) + feedforward_mat = Matrix([1]) + system = StateSpace(state_mat, input_mat, output_mat, feedforward_mat) + + assert SS_neg == \ + StateSpace(Matrix([[a0, a1], + [a2, a3]]), + Matrix([[b0, b1], + [b2, b3]]), + Matrix([[-c0, -c1], + [-c1, -c2], + [-c2, -c3]]), + Matrix([[-d0, -d1], + [-d1, -d2], + [-d2, -d3]])) + assert -system == \ + StateSpace(Matrix([[-1, 1], + [ 1, -1]]), + Matrix([[ 1],[-1]]), + Matrix([[1, -1]]), + Matrix([[-1]])) + assert -SS_neg == SS + assert -(-(-(-system))) == system + +def test_SymPy_substitution_functions(): + # subs + ss1 = StateSpace(Matrix([s]), Matrix([(s + 1)**2]), Matrix([s**2 - 1]), Matrix([2*s])) + ss2 = StateSpace(Matrix([s + p]), Matrix([(s + 1)*(p - 1)]), Matrix([p**3 - s**3]), Matrix([s - p])) + + assert ss1.subs({s:5}) == StateSpace(Matrix([[5]]), Matrix([[36]]), Matrix([[24]]), Matrix([[10]])) + assert ss2.subs({p:1}) == StateSpace(Matrix([[s + 1]]), Matrix([[0]]), Matrix([[1 - s**3]]), Matrix([[s - 1]])) + + # xreplace + assert ss1.xreplace({s:p}) == \ + StateSpace(Matrix([[p]]), Matrix([[(p + 1)**2]]), Matrix([[p**2 - 1]]), Matrix([[2*p]])) + assert ss2.xreplace({s:a, p:b}) == \ + StateSpace(Matrix([[a + b]]), Matrix([[(a + 1)*(b - 1)]]), Matrix([[-a**3 + b**3]]), Matrix([[a - b]])) + + # evalf + p1 = a1*s + a0 + p2 = b2*s**2 + b1*s + b0 + G = StateSpace(Matrix([p1]), Matrix([p2])) + expect = StateSpace(Matrix([[2*s + 1]]), Matrix([[5*s**2 + 4*s + 3]]), Matrix([[0]]), Matrix([[0]])) + expect_ = StateSpace(Matrix([[2.0*s + 1.0]]), Matrix([[5.0*s**2 + 4.0*s + 3.0]]), Matrix([[0]]), Matrix([[0]])) + assert G.subs({a0: 1, a1: 2, b0: 3, b1: 4, b2: 5}) == expect + assert G.subs({a0: 1, a1: 2, b0: 3, b1: 4, b2: 5}).evalf() == expect_ + assert expect.evalf() == expect_ + +def test_conversion(): + # StateSpace to TransferFunction for SISO + A1 = Matrix([[-5, -1], [3, -1]]) + B1 = Matrix([2, 5]) + C1 = Matrix([[1, 2]]) + D1 = Matrix([0]) + H1 = StateSpace(A1, B1, C1, D1) + tm1 = H1.rewrite(TransferFunction) + tm2 = (-H1).rewrite(TransferFunction) + + tf1 = tm1[0][0] + tf2 = tm2[0][0] + + assert tf1 == TransferFunction(12*s + 59, s**2 + 6*s + 8, s) + assert tf2.num == -tf1.num + assert tf2.den == tf1.den + + # StateSpace to TransferFunction for MIMO + A2 = Matrix([[-1.5, -2, 3], [1, 0, 1], [2, 1, 1]]) + B2 = Matrix([[0.5, 0, 1], [0, 1, 2], [2, 2, 3]]) + C2 = Matrix([[0, 1, 0], [0, 2, 1], [1, 0, 2]]) + D2 = Matrix([[2, 2, 0], [1, 1, 1], [3, 2, 1]]) + H2 = StateSpace(A2, B2, C2, D2) + tm3 = H2.rewrite(TransferFunction) + + # outputs for input i obtained at Index i-1. Consider input 1 + assert tm3[0][0] == TransferFunction(2.0*s**3 + 1.0*s**2 - 10.5*s + 4.5, 1.0*s**3 + 0.5*s**2 - 6.5*s - 2.5, s) + assert tm3[0][1] == TransferFunction(2.0*s**3 + 2.0*s**2 - 10.5*s - 3.5, 1.0*s**3 + 0.5*s**2 - 6.5*s - 2.5, s) + assert tm3[0][2] == TransferFunction(2.0*s**2 + 5.0*s - 0.5, 1.0*s**3 + 0.5*s**2 - 6.5*s - 2.5, s) + + # TransferFunction to StateSpace + SS = TF1.rewrite(StateSpace) + assert SS == \ + StateSpace(Matrix([[ 0, 1], + [-wn**2, -2*wn*zeta]]), + Matrix([[0], + [1]]), + Matrix([[1, 0]]), + Matrix([[0]])) + assert SS.rewrite(TransferFunction)[0][0] == TF1 + + # Transfer function has to be proper + raises(ValueError, lambda: TransferFunction(b*s**2 + p**2 - a*p + s, b - p**2, s).rewrite(StateSpace)) + + +def test_StateSpace_functions(): + # https://in.mathworks.com/help/control/ref/statespacemodel.obsv.html + + A_mat = Matrix([[-1.5, -2], [1, 0]]) + B_mat = Matrix([0.5, 0]) + C_mat = Matrix([[0, 1]]) + D_mat = Matrix([1]) + SS1 = StateSpace(A_mat, B_mat, C_mat, D_mat) + SS2 = StateSpace(Matrix([[1, 1], [4, -2]]),Matrix([[0, 1], [0, 2]]),Matrix([[-1, 1], [1, -1]])) + SS3 = StateSpace(Matrix([[1, 1], [4, -2]]),Matrix([[1, -1], [1, -1]])) + + # Observability + assert SS1.is_observable() == True + assert SS2.is_observable() == False + assert SS1.observability_matrix() == Matrix([[0, 1], [1, 0]]) + assert SS2.observability_matrix() == Matrix([[-1, 1], [ 1, -1], [ 3, -3], [-3, 3]]) + assert SS1.observable_subspace() == [Matrix([[0], [1]]), Matrix([[1], [0]])] + assert SS2.observable_subspace() == [Matrix([[-1], [ 1], [ 3], [-3]])] + + # Controllability + assert SS1.is_controllable() == True + assert SS3.is_controllable() == False + assert SS1.controllability_matrix() == Matrix([[0.5, -0.75], [ 0, 0.5]]) + assert SS3.controllability_matrix() == Matrix([[1, -1, 2, -2], [1, -1, 2, -2]]) + assert SS1.controllable_subspace() == [Matrix([[0.5], [ 0]]), Matrix([[-0.75], [ 0.5]])] + assert SS3.controllable_subspace() == [Matrix([[1], [1]])] + + # Append + A1 = Matrix([[0, 1], [1, 0]]) + B1 = Matrix([[0], [1]]) + C1 = Matrix([[0, 1]]) + D1 = Matrix([[0]]) + ss1 = StateSpace(A1, B1, C1, D1) + ss2 = StateSpace(Matrix([[1, 0], [0, 1]]), Matrix([[1], [0]]), Matrix([[1, 0]]), Matrix([[1]])) + ss3 = ss1.append(ss2) + + assert ss3.num_states == ss1.num_states + ss2.num_states + assert ss3.num_inputs == ss1.num_inputs + ss2.num_inputs + assert ss3.num_outputs == ss1.num_outputs + ss2.num_outputs + assert ss3.state_matrix == Matrix([[0, 1, 0, 0], [1, 0, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) + assert ss3.input_matrix == Matrix([[0, 0], [1, 0], [0, 1], [0, 0]]) + assert ss3.output_matrix == Matrix([[0, 1, 0, 0], [0, 0, 1, 0]]) + assert ss3.feedforward_matrix == Matrix([[0, 0], [0, 1]]) diff --git a/lib/python3.12/site-packages/sympy/physics/hep/__init__.py b/lib/python3.12/site-packages/sympy/physics/hep/__init__.py new file mode 100644 index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 diff --git a/lib/python3.12/site-packages/sympy/physics/hep/__pycache__/__init__.cpython-312.pyc b/lib/python3.12/site-packages/sympy/physics/hep/__pycache__/__init__.cpython-312.pyc new file mode 100644 index 0000000000000000000000000000000000000000..7d0907be77196ea56965e29e5be411373d986a14 Binary files /dev/null and b/lib/python3.12/site-packages/sympy/physics/hep/__pycache__/__init__.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/hep/__pycache__/gamma_matrices.cpython-312.pyc b/lib/python3.12/site-packages/sympy/physics/hep/__pycache__/gamma_matrices.cpython-312.pyc new file mode 100644 index 0000000000000000000000000000000000000000..3ed9ed130e8fceedd03428ebdc9f51b517ccc342 Binary files /dev/null and b/lib/python3.12/site-packages/sympy/physics/hep/__pycache__/gamma_matrices.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/hep/gamma_matrices.py b/lib/python3.12/site-packages/sympy/physics/hep/gamma_matrices.py new file mode 100644 index 0000000000000000000000000000000000000000..40c3d0754438902f304d01c2df354dd09f9ea257 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/hep/gamma_matrices.py @@ -0,0 +1,716 @@ +""" + Module to handle gamma matrices expressed as tensor objects. + + Examples + ======== + + >>> from sympy.physics.hep.gamma_matrices import GammaMatrix as G, LorentzIndex + >>> from sympy.tensor.tensor import tensor_indices + >>> i = tensor_indices('i', LorentzIndex) + >>> G(i) + GammaMatrix(i) + + Note that there is already an instance of GammaMatrixHead in four dimensions: + GammaMatrix, which is simply declare as + + >>> from sympy.physics.hep.gamma_matrices import GammaMatrix + >>> from sympy.tensor.tensor import tensor_indices + >>> i = tensor_indices('i', LorentzIndex) + >>> GammaMatrix(i) + GammaMatrix(i) + + To access the metric tensor + + >>> LorentzIndex.metric + metric(LorentzIndex,LorentzIndex) + +""" +from sympy.core.mul import Mul +from sympy.core.singleton import S +from sympy.matrices.dense import eye +from sympy.matrices.expressions.trace import trace +from sympy.tensor.tensor import TensorIndexType, TensorIndex,\ + TensMul, TensAdd, tensor_mul, Tensor, TensorHead, TensorSymmetry + + +# DiracSpinorIndex = TensorIndexType('DiracSpinorIndex', dim=4, dummy_name="S") + + +LorentzIndex = TensorIndexType('LorentzIndex', dim=4, dummy_name="L") + + +GammaMatrix = TensorHead("GammaMatrix", [LorentzIndex], + TensorSymmetry.no_symmetry(1), comm=None) + + +def extract_type_tens(expression, component): + """ + Extract from a ``TensExpr`` all tensors with `component`. + + Returns two tensor expressions: + + * the first contains all ``Tensor`` of having `component`. + * the second contains all remaining. + + + """ + if isinstance(expression, Tensor): + sp = [expression] + elif isinstance(expression, TensMul): + sp = expression.args + else: + raise ValueError('wrong type') + + # Collect all gamma matrices of the same dimension + new_expr = S.One + residual_expr = S.One + for i in sp: + if isinstance(i, Tensor) and i.component == component: + new_expr *= i + else: + residual_expr *= i + return new_expr, residual_expr + + +def simplify_gamma_expression(expression): + extracted_expr, residual_expr = extract_type_tens(expression, GammaMatrix) + res_expr = _simplify_single_line(extracted_expr) + return res_expr * residual_expr + + +def simplify_gpgp(ex, sort=True): + """ + simplify products ``G(i)*p(-i)*G(j)*p(-j) -> p(i)*p(-i)`` + + Examples + ======== + + >>> from sympy.physics.hep.gamma_matrices import GammaMatrix as G, \ + LorentzIndex, simplify_gpgp + >>> from sympy.tensor.tensor import tensor_indices, tensor_heads + >>> p, q = tensor_heads('p, q', [LorentzIndex]) + >>> i0,i1,i2,i3,i4,i5 = tensor_indices('i0:6', LorentzIndex) + >>> ps = p(i0)*G(-i0) + >>> qs = q(i0)*G(-i0) + >>> simplify_gpgp(ps*qs*qs) + GammaMatrix(-L_0)*p(L_0)*q(L_1)*q(-L_1) + """ + def _simplify_gpgp(ex): + components = ex.components + a = [] + comp_map = [] + for i, comp in enumerate(components): + comp_map.extend([i]*comp.rank) + dum = [(i[0], i[1], comp_map[i[0]], comp_map[i[1]]) for i in ex.dum] + for i in range(len(components)): + if components[i] != GammaMatrix: + continue + for dx in dum: + if dx[2] == i: + p_pos1 = dx[3] + elif dx[3] == i: + p_pos1 = dx[2] + else: + continue + comp1 = components[p_pos1] + if comp1.comm == 0 and comp1.rank == 1: + a.append((i, p_pos1)) + if not a: + return ex + elim = set() + tv = [] + hit = True + coeff = S.One + ta = None + while hit: + hit = False + for i, ai in enumerate(a[:-1]): + if ai[0] in elim: + continue + if ai[0] != a[i + 1][0] - 1: + continue + if components[ai[1]] != components[a[i + 1][1]]: + continue + elim.add(ai[0]) + elim.add(ai[1]) + elim.add(a[i + 1][0]) + elim.add(a[i + 1][1]) + if not ta: + ta = ex.split() + mu = TensorIndex('mu', LorentzIndex) + hit = True + if i == 0: + coeff = ex.coeff + tx = components[ai[1]](mu)*components[ai[1]](-mu) + if len(a) == 2: + tx *= 4 # eye(4) + tv.append(tx) + break + + if tv: + a = [x for j, x in enumerate(ta) if j not in elim] + a.extend(tv) + t = tensor_mul(*a)*coeff + # t = t.replace(lambda x: x.is_Matrix, lambda x: 1) + return t + else: + return ex + + if sort: + ex = ex.sorted_components() + # this would be better off with pattern matching + while 1: + t = _simplify_gpgp(ex) + if t != ex: + ex = t + else: + return t + + +def gamma_trace(t): + """ + trace of a single line of gamma matrices + + Examples + ======== + + >>> from sympy.physics.hep.gamma_matrices import GammaMatrix as G, \ + gamma_trace, LorentzIndex + >>> from sympy.tensor.tensor import tensor_indices, tensor_heads + >>> p, q = tensor_heads('p, q', [LorentzIndex]) + >>> i0,i1,i2,i3,i4,i5 = tensor_indices('i0:6', LorentzIndex) + >>> ps = p(i0)*G(-i0) + >>> qs = q(i0)*G(-i0) + >>> gamma_trace(G(i0)*G(i1)) + 4*metric(i0, i1) + >>> gamma_trace(ps*ps) - 4*p(i0)*p(-i0) + 0 + >>> gamma_trace(ps*qs + ps*ps) - 4*p(i0)*p(-i0) - 4*p(i0)*q(-i0) + 0 + + """ + if isinstance(t, TensAdd): + res = TensAdd(*[gamma_trace(x) for x in t.args]) + return res + t = _simplify_single_line(t) + res = _trace_single_line(t) + return res + + +def _simplify_single_line(expression): + """ + Simplify single-line product of gamma matrices. + + Examples + ======== + + >>> from sympy.physics.hep.gamma_matrices import GammaMatrix as G, \ + LorentzIndex, _simplify_single_line + >>> from sympy.tensor.tensor import tensor_indices, TensorHead + >>> p = TensorHead('p', [LorentzIndex]) + >>> i0,i1 = tensor_indices('i0:2', LorentzIndex) + >>> _simplify_single_line(G(i0)*G(i1)*p(-i1)*G(-i0)) + 2*G(i0)*p(-i0) + 0 + + """ + t1, t2 = extract_type_tens(expression, GammaMatrix) + if t1 != 1: + t1 = kahane_simplify(t1) + res = t1*t2 + return res + + +def _trace_single_line(t): + """ + Evaluate the trace of a single gamma matrix line inside a ``TensExpr``. + + Notes + ===== + + If there are ``DiracSpinorIndex.auto_left`` and ``DiracSpinorIndex.auto_right`` + indices trace over them; otherwise traces are not implied (explain) + + + Examples + ======== + + >>> from sympy.physics.hep.gamma_matrices import GammaMatrix as G, \ + LorentzIndex, _trace_single_line + >>> from sympy.tensor.tensor import tensor_indices, TensorHead + >>> p = TensorHead('p', [LorentzIndex]) + >>> i0,i1,i2,i3,i4,i5 = tensor_indices('i0:6', LorentzIndex) + >>> _trace_single_line(G(i0)*G(i1)) + 4*metric(i0, i1) + >>> _trace_single_line(G(i0)*p(-i0)*G(i1)*p(-i1)) - 4*p(i0)*p(-i0) + 0 + + """ + def _trace_single_line1(t): + t = t.sorted_components() + components = t.components + ncomps = len(components) + g = LorentzIndex.metric + # gamma matirices are in a[i:j] + hit = 0 + for i in range(ncomps): + if components[i] == GammaMatrix: + hit = 1 + break + + for j in range(i + hit, ncomps): + if components[j] != GammaMatrix: + break + else: + j = ncomps + numG = j - i + if numG == 0: + tcoeff = t.coeff + return t.nocoeff if tcoeff else t + if numG % 2 == 1: + return TensMul.from_data(S.Zero, [], [], []) + elif numG > 4: + # find the open matrix indices and connect them: + a = t.split() + ind1 = a[i].get_indices()[0] + ind2 = a[i + 1].get_indices()[0] + aa = a[:i] + a[i + 2:] + t1 = tensor_mul(*aa)*g(ind1, ind2) + t1 = t1.contract_metric(g) + args = [t1] + sign = 1 + for k in range(i + 2, j): + sign = -sign + ind2 = a[k].get_indices()[0] + aa = a[:i] + a[i + 1:k] + a[k + 1:] + t2 = sign*tensor_mul(*aa)*g(ind1, ind2) + t2 = t2.contract_metric(g) + t2 = simplify_gpgp(t2, False) + args.append(t2) + t3 = TensAdd(*args) + t3 = _trace_single_line(t3) + return t3 + else: + a = t.split() + t1 = _gamma_trace1(*a[i:j]) + a2 = a[:i] + a[j:] + t2 = tensor_mul(*a2) + t3 = t1*t2 + if not t3: + return t3 + t3 = t3.contract_metric(g) + return t3 + + t = t.expand() + if isinstance(t, TensAdd): + a = [_trace_single_line1(x)*x.coeff for x in t.args] + return TensAdd(*a) + elif isinstance(t, (Tensor, TensMul)): + r = t.coeff*_trace_single_line1(t) + return r + else: + return trace(t) + + +def _gamma_trace1(*a): + gctr = 4 # FIXME specific for d=4 + g = LorentzIndex.metric + if not a: + return gctr + n = len(a) + if n%2 == 1: + #return TensMul.from_data(S.Zero, [], [], []) + return S.Zero + if n == 2: + ind0 = a[0].get_indices()[0] + ind1 = a[1].get_indices()[0] + return gctr*g(ind0, ind1) + if n == 4: + ind0 = a[0].get_indices()[0] + ind1 = a[1].get_indices()[0] + ind2 = a[2].get_indices()[0] + ind3 = a[3].get_indices()[0] + + return gctr*(g(ind0, ind1)*g(ind2, ind3) - \ + g(ind0, ind2)*g(ind1, ind3) + g(ind0, ind3)*g(ind1, ind2)) + + +def kahane_simplify(expression): + r""" + This function cancels contracted elements in a product of four + dimensional gamma matrices, resulting in an expression equal to the given + one, without the contracted gamma matrices. + + Parameters + ========== + + `expression` the tensor expression containing the gamma matrices to simplify. + + Notes + ===== + + If spinor indices are given, the matrices must be given in + the order given in the product. + + Algorithm + ========= + + The idea behind the algorithm is to use some well-known identities, + i.e., for contractions enclosing an even number of `\gamma` matrices + + `\gamma^\mu \gamma_{a_1} \cdots \gamma_{a_{2N}} \gamma_\mu = 2 (\gamma_{a_{2N}} \gamma_{a_1} \cdots \gamma_{a_{2N-1}} + \gamma_{a_{2N-1}} \cdots \gamma_{a_1} \gamma_{a_{2N}} )` + + for an odd number of `\gamma` matrices + + `\gamma^\mu \gamma_{a_1} \cdots \gamma_{a_{2N+1}} \gamma_\mu = -2 \gamma_{a_{2N+1}} \gamma_{a_{2N}} \cdots \gamma_{a_{1}}` + + Instead of repeatedly applying these identities to cancel out all contracted indices, + it is possible to recognize the links that would result from such an operation, + the problem is thus reduced to a simple rearrangement of free gamma matrices. + + Examples + ======== + + When using, always remember that the original expression coefficient + has to be handled separately + + >>> from sympy.physics.hep.gamma_matrices import GammaMatrix as G, LorentzIndex + >>> from sympy.physics.hep.gamma_matrices import kahane_simplify + >>> from sympy.tensor.tensor import tensor_indices + >>> i0, i1, i2 = tensor_indices('i0:3', LorentzIndex) + >>> ta = G(i0)*G(-i0) + >>> kahane_simplify(ta) + Matrix([ + [4, 0, 0, 0], + [0, 4, 0, 0], + [0, 0, 4, 0], + [0, 0, 0, 4]]) + >>> tb = G(i0)*G(i1)*G(-i0) + >>> kahane_simplify(tb) + -2*GammaMatrix(i1) + >>> t = G(i0)*G(-i0) + >>> kahane_simplify(t) + Matrix([ + [4, 0, 0, 0], + [0, 4, 0, 0], + [0, 0, 4, 0], + [0, 0, 0, 4]]) + >>> t = G(i0)*G(-i0) + >>> kahane_simplify(t) + Matrix([ + [4, 0, 0, 0], + [0, 4, 0, 0], + [0, 0, 4, 0], + [0, 0, 0, 4]]) + + If there are no contractions, the same expression is returned + + >>> tc = G(i0)*G(i1) + >>> kahane_simplify(tc) + GammaMatrix(i0)*GammaMatrix(i1) + + References + ========== + + [1] Algorithm for Reducing Contracted Products of gamma Matrices, + Joseph Kahane, Journal of Mathematical Physics, Vol. 9, No. 10, October 1968. + """ + + if isinstance(expression, Mul): + return expression + if isinstance(expression, TensAdd): + return TensAdd(*[kahane_simplify(arg) for arg in expression.args]) + + if isinstance(expression, Tensor): + return expression + + assert isinstance(expression, TensMul) + + gammas = expression.args + + for gamma in gammas: + assert gamma.component == GammaMatrix + + free = expression.free + # spinor_free = [_ for _ in expression.free_in_args if _[1] != 0] + + # if len(spinor_free) == 2: + # spinor_free.sort(key=lambda x: x[2]) + # assert spinor_free[0][1] == 1 and spinor_free[-1][1] == 2 + # assert spinor_free[0][2] == 0 + # elif spinor_free: + # raise ValueError('spinor indices do not match') + + dum = [] + for dum_pair in expression.dum: + if expression.index_types[dum_pair[0]] == LorentzIndex: + dum.append((dum_pair[0], dum_pair[1])) + + dum = sorted(dum) + + if len(dum) == 0: # or GammaMatrixHead: + # no contractions in `expression`, just return it. + return expression + + # find the `first_dum_pos`, i.e. the position of the first contracted + # gamma matrix, Kahane's algorithm as described in his paper requires the + # gamma matrix expression to start with a contracted gamma matrix, this is + # a workaround which ignores possible initial free indices, and re-adds + # them later. + + first_dum_pos = min(map(min, dum)) + + # for p1, p2, a1, a2 in expression.dum_in_args: + # if p1 != 0 or p2 != 0: + # # only Lorentz indices, skip Dirac indices: + # continue + # first_dum_pos = min(p1, p2) + # break + + total_number = len(free) + len(dum)*2 + number_of_contractions = len(dum) + + free_pos = [None]*total_number + for i in free: + free_pos[i[1]] = i[0] + + # `index_is_free` is a list of booleans, to identify index position + # and whether that index is free or dummy. + index_is_free = [False]*total_number + + for i, indx in enumerate(free): + index_is_free[indx[1]] = True + + # `links` is a dictionary containing the graph described in Kahane's paper, + # to every key correspond one or two values, representing the linked indices. + # All values in `links` are integers, negative numbers are used in the case + # where it is necessary to insert gamma matrices between free indices, in + # order to make Kahane's algorithm work (see paper). + links = {i: [] for i in range(first_dum_pos, total_number)} + + # `cum_sign` is a step variable to mark the sign of every index, see paper. + cum_sign = -1 + # `cum_sign_list` keeps storage for all `cum_sign` (every index). + cum_sign_list = [None]*total_number + block_free_count = 0 + + # multiply `resulting_coeff` by the coefficient parameter, the rest + # of the algorithm ignores a scalar coefficient. + resulting_coeff = S.One + + # initialize a list of lists of indices. The outer list will contain all + # additive tensor expressions, while the inner list will contain the + # free indices (rearranged according to the algorithm). + resulting_indices = [[]] + + # start to count the `connected_components`, which together with the number + # of contractions, determines a -1 or +1 factor to be multiplied. + connected_components = 1 + + # First loop: here we fill `cum_sign_list`, and draw the links + # among consecutive indices (they are stored in `links`). Links among + # non-consecutive indices will be drawn later. + for i, is_free in enumerate(index_is_free): + # if `expression` starts with free indices, they are ignored here; + # they are later added as they are to the beginning of all + # `resulting_indices` list of lists of indices. + if i < first_dum_pos: + continue + + if is_free: + block_free_count += 1 + # if previous index was free as well, draw an arch in `links`. + if block_free_count > 1: + links[i - 1].append(i) + links[i].append(i - 1) + else: + # Change the sign of the index (`cum_sign`) if the number of free + # indices preceding it is even. + cum_sign *= 1 if (block_free_count % 2) else -1 + if block_free_count == 0 and i != first_dum_pos: + # check if there are two consecutive dummy indices: + # in this case create virtual indices with negative position, + # these "virtual" indices represent the insertion of two + # gamma^0 matrices to separate consecutive dummy indices, as + # Kahane's algorithm requires dummy indices to be separated by + # free indices. The product of two gamma^0 matrices is unity, + # so the new expression being examined is the same as the + # original one. + if cum_sign == -1: + links[-1-i] = [-1-i+1] + links[-1-i+1] = [-1-i] + if (i - cum_sign) in links: + if i != first_dum_pos: + links[i].append(i - cum_sign) + if block_free_count != 0: + if i - cum_sign < len(index_is_free): + if index_is_free[i - cum_sign]: + links[i - cum_sign].append(i) + block_free_count = 0 + + cum_sign_list[i] = cum_sign + + # The previous loop has only created links between consecutive free indices, + # it is necessary to properly create links among dummy (contracted) indices, + # according to the rules described in Kahane's paper. There is only one exception + # to Kahane's rules: the negative indices, which handle the case of some + # consecutive free indices (Kahane's paper just describes dummy indices + # separated by free indices, hinting that free indices can be added without + # altering the expression result). + for i in dum: + # get the positions of the two contracted indices: + pos1 = i[0] + pos2 = i[1] + + # create Kahane's upper links, i.e. the upper arcs between dummy + # (i.e. contracted) indices: + links[pos1].append(pos2) + links[pos2].append(pos1) + + # create Kahane's lower links, this corresponds to the arcs below + # the line described in the paper: + + # first we move `pos1` and `pos2` according to the sign of the indices: + linkpos1 = pos1 + cum_sign_list[pos1] + linkpos2 = pos2 + cum_sign_list[pos2] + + # otherwise, perform some checks before creating the lower arcs: + + # make sure we are not exceeding the total number of indices: + if linkpos1 >= total_number: + continue + if linkpos2 >= total_number: + continue + + # make sure we are not below the first dummy index in `expression`: + if linkpos1 < first_dum_pos: + continue + if linkpos2 < first_dum_pos: + continue + + # check if the previous loop created "virtual" indices between dummy + # indices, in such a case relink `linkpos1` and `linkpos2`: + if (-1-linkpos1) in links: + linkpos1 = -1-linkpos1 + if (-1-linkpos2) in links: + linkpos2 = -1-linkpos2 + + # move only if not next to free index: + if linkpos1 >= 0 and not index_is_free[linkpos1]: + linkpos1 = pos1 + + if linkpos2 >=0 and not index_is_free[linkpos2]: + linkpos2 = pos2 + + # create the lower arcs: + if linkpos2 not in links[linkpos1]: + links[linkpos1].append(linkpos2) + if linkpos1 not in links[linkpos2]: + links[linkpos2].append(linkpos1) + + # This loop starts from the `first_dum_pos` index (first dummy index) + # walks through the graph deleting the visited indices from `links`, + # it adds a gamma matrix for every free index in encounters, while it + # completely ignores dummy indices and virtual indices. + pointer = first_dum_pos + previous_pointer = 0 + while True: + if pointer in links: + next_ones = links.pop(pointer) + else: + break + + if previous_pointer in next_ones: + next_ones.remove(previous_pointer) + + previous_pointer = pointer + + if next_ones: + pointer = next_ones[0] + else: + break + + if pointer == previous_pointer: + break + if pointer >=0 and free_pos[pointer] is not None: + for ri in resulting_indices: + ri.append(free_pos[pointer]) + + # The following loop removes the remaining connected components in `links`. + # If there are free indices inside a connected component, it gives a + # contribution to the resulting expression given by the factor + # `gamma_a gamma_b ... gamma_z + gamma_z ... gamma_b gamma_a`, in Kahanes's + # paper represented as {gamma_a, gamma_b, ... , gamma_z}, + # virtual indices are ignored. The variable `connected_components` is + # increased by one for every connected component this loop encounters. + + # If the connected component has virtual and dummy indices only + # (no free indices), it contributes to `resulting_indices` by a factor of two. + # The multiplication by two is a result of the + # factor {gamma^0, gamma^0} = 2 I, as it appears in Kahane's paper. + # Note: curly brackets are meant as in the paper, as a generalized + # multi-element anticommutator! + + while links: + connected_components += 1 + pointer = min(links.keys()) + previous_pointer = pointer + # the inner loop erases the visited indices from `links`, and it adds + # all free indices to `prepend_indices` list, virtual indices are + # ignored. + prepend_indices = [] + while True: + if pointer in links: + next_ones = links.pop(pointer) + else: + break + + if previous_pointer in next_ones: + if len(next_ones) > 1: + next_ones.remove(previous_pointer) + + previous_pointer = pointer + + if next_ones: + pointer = next_ones[0] + + if pointer >= first_dum_pos and free_pos[pointer] is not None: + prepend_indices.insert(0, free_pos[pointer]) + # if `prepend_indices` is void, it means there are no free indices + # in the loop (and it can be shown that there must be a virtual index), + # loops of virtual indices only contribute by a factor of two: + if len(prepend_indices) == 0: + resulting_coeff *= 2 + # otherwise, add the free indices in `prepend_indices` to + # the `resulting_indices`: + else: + expr1 = prepend_indices + expr2 = list(reversed(prepend_indices)) + resulting_indices = [expri + ri for ri in resulting_indices for expri in (expr1, expr2)] + + # sign correction, as described in Kahane's paper: + resulting_coeff *= -1 if (number_of_contractions - connected_components + 1) % 2 else 1 + # power of two factor, as described in Kahane's paper: + resulting_coeff *= 2**(number_of_contractions) + + # If `first_dum_pos` is not zero, it means that there are trailing free gamma + # matrices in front of `expression`, so multiply by them: + resulting_indices = [ free_pos[0:first_dum_pos] + ri for ri in resulting_indices ] + + resulting_expr = S.Zero + for i in resulting_indices: + temp_expr = S.One + for j in i: + temp_expr *= GammaMatrix(j) + resulting_expr += temp_expr + + t = resulting_coeff * resulting_expr + t1 = None + if isinstance(t, TensAdd): + t1 = t.args[0] + elif isinstance(t, TensMul): + t1 = t + if t1: + pass + else: + t = eye(4)*t + return t diff --git a/lib/python3.12/site-packages/sympy/physics/hep/tests/__init__.py b/lib/python3.12/site-packages/sympy/physics/hep/tests/__init__.py new file mode 100644 index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 diff --git a/lib/python3.12/site-packages/sympy/physics/hep/tests/__pycache__/__init__.cpython-312.pyc b/lib/python3.12/site-packages/sympy/physics/hep/tests/__pycache__/__init__.cpython-312.pyc new file mode 100644 index 0000000000000000000000000000000000000000..14c1e9e08c4d9fe686b0e10122b13a3f7c789263 Binary files /dev/null and b/lib/python3.12/site-packages/sympy/physics/hep/tests/__pycache__/__init__.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/hep/tests/__pycache__/test_gamma_matrices.cpython-312.pyc b/lib/python3.12/site-packages/sympy/physics/hep/tests/__pycache__/test_gamma_matrices.cpython-312.pyc new file mode 100644 index 0000000000000000000000000000000000000000..1c13af59384e822abd53682837d7cba68867b0dc Binary files /dev/null and b/lib/python3.12/site-packages/sympy/physics/hep/tests/__pycache__/test_gamma_matrices.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/hep/tests/test_gamma_matrices.py b/lib/python3.12/site-packages/sympy/physics/hep/tests/test_gamma_matrices.py new file mode 100644 index 0000000000000000000000000000000000000000..1552cf0d19be222ba249a7e32c65c8c3abc54ac2 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/hep/tests/test_gamma_matrices.py @@ -0,0 +1,427 @@ +from sympy.matrices.dense import eye, Matrix +from sympy.tensor.tensor import tensor_indices, TensorHead, tensor_heads, \ + TensExpr, canon_bp +from sympy.physics.hep.gamma_matrices import GammaMatrix as G, LorentzIndex, \ + kahane_simplify, gamma_trace, _simplify_single_line, simplify_gamma_expression +from sympy import Symbol + + +def _is_tensor_eq(arg1, arg2): + arg1 = canon_bp(arg1) + arg2 = canon_bp(arg2) + if isinstance(arg1, TensExpr): + return arg1.equals(arg2) + elif isinstance(arg2, TensExpr): + return arg2.equals(arg1) + return arg1 == arg2 + +def execute_gamma_simplify_tests_for_function(tfunc, D): + """ + Perform tests to check if sfunc is able to simplify gamma matrix expressions. + + Parameters + ========== + + `sfunc` a function to simplify a `TIDS`, shall return the simplified `TIDS`. + `D` the number of dimension (in most cases `D=4`). + + """ + + mu, nu, rho, sigma = tensor_indices("mu, nu, rho, sigma", LorentzIndex) + a1, a2, a3, a4, a5, a6 = tensor_indices("a1:7", LorentzIndex) + mu11, mu12, mu21, mu31, mu32, mu41, mu51, mu52 = tensor_indices("mu11, mu12, mu21, mu31, mu32, mu41, mu51, mu52", LorentzIndex) + mu61, mu71, mu72 = tensor_indices("mu61, mu71, mu72", LorentzIndex) + m0, m1, m2, m3, m4, m5, m6 = tensor_indices("m0:7", LorentzIndex) + + def g(xx, yy): + return (G(xx)*G(yy) + G(yy)*G(xx))/2 + + # Some examples taken from Kahane's paper, 4 dim only: + if D == 4: + t = (G(a1)*G(mu11)*G(a2)*G(mu21)*G(-a1)*G(mu31)*G(-a2)) + assert _is_tensor_eq(tfunc(t), -4*G(mu11)*G(mu31)*G(mu21) - 4*G(mu31)*G(mu11)*G(mu21)) + + t = (G(a1)*G(mu11)*G(mu12)*\ + G(a2)*G(mu21)*\ + G(a3)*G(mu31)*G(mu32)*\ + G(a4)*G(mu41)*\ + G(-a2)*G(mu51)*G(mu52)*\ + G(-a1)*G(mu61)*\ + G(-a3)*G(mu71)*G(mu72)*\ + G(-a4)) + assert _is_tensor_eq(tfunc(t), \ + 16*G(mu31)*G(mu32)*G(mu72)*G(mu71)*G(mu11)*G(mu52)*G(mu51)*G(mu12)*G(mu61)*G(mu21)*G(mu41) + 16*G(mu31)*G(mu32)*G(mu72)*G(mu71)*G(mu12)*G(mu51)*G(mu52)*G(mu11)*G(mu61)*G(mu21)*G(mu41) + 16*G(mu71)*G(mu72)*G(mu32)*G(mu31)*G(mu11)*G(mu52)*G(mu51)*G(mu12)*G(mu61)*G(mu21)*G(mu41) + 16*G(mu71)*G(mu72)*G(mu32)*G(mu31)*G(mu12)*G(mu51)*G(mu52)*G(mu11)*G(mu61)*G(mu21)*G(mu41)) + + # Fully Lorentz-contracted expressions, these return scalars: + + def add_delta(ne): + return ne * eye(4) # DiracSpinorIndex.delta(DiracSpinorIndex.auto_left, -DiracSpinorIndex.auto_right) + + t = (G(mu)*G(-mu)) + ts = add_delta(D) + assert _is_tensor_eq(tfunc(t), ts) + + t = (G(mu)*G(nu)*G(-mu)*G(-nu)) + ts = add_delta(2*D - D**2) # -8 + assert _is_tensor_eq(tfunc(t), ts) + + t = (G(mu)*G(nu)*G(-nu)*G(-mu)) + ts = add_delta(D**2) # 16 + assert _is_tensor_eq(tfunc(t), ts) + + t = (G(mu)*G(nu)*G(-rho)*G(-nu)*G(-mu)*G(rho)) + ts = add_delta(4*D - 4*D**2 + D**3) # 16 + assert _is_tensor_eq(tfunc(t), ts) + + t = (G(mu)*G(nu)*G(rho)*G(-rho)*G(-nu)*G(-mu)) + ts = add_delta(D**3) # 64 + assert _is_tensor_eq(tfunc(t), ts) + + t = (G(a1)*G(a2)*G(a3)*G(a4)*G(-a3)*G(-a1)*G(-a2)*G(-a4)) + ts = add_delta(-8*D + 16*D**2 - 8*D**3 + D**4) # -32 + assert _is_tensor_eq(tfunc(t), ts) + + t = (G(-mu)*G(-nu)*G(-rho)*G(-sigma)*G(nu)*G(mu)*G(sigma)*G(rho)) + ts = add_delta(-16*D + 24*D**2 - 8*D**3 + D**4) # 64 + assert _is_tensor_eq(tfunc(t), ts) + + t = (G(-mu)*G(nu)*G(-rho)*G(sigma)*G(rho)*G(-nu)*G(mu)*G(-sigma)) + ts = add_delta(8*D - 12*D**2 + 6*D**3 - D**4) # -32 + assert _is_tensor_eq(tfunc(t), ts) + + t = (G(a1)*G(a2)*G(a3)*G(a4)*G(a5)*G(-a3)*G(-a2)*G(-a1)*G(-a5)*G(-a4)) + ts = add_delta(64*D - 112*D**2 + 60*D**3 - 12*D**4 + D**5) # 256 + assert _is_tensor_eq(tfunc(t), ts) + + t = (G(a1)*G(a2)*G(a3)*G(a4)*G(a5)*G(-a3)*G(-a1)*G(-a2)*G(-a4)*G(-a5)) + ts = add_delta(64*D - 120*D**2 + 72*D**3 - 16*D**4 + D**5) # -128 + assert _is_tensor_eq(tfunc(t), ts) + + t = (G(a1)*G(a2)*G(a3)*G(a4)*G(a5)*G(a6)*G(-a3)*G(-a2)*G(-a1)*G(-a6)*G(-a5)*G(-a4)) + ts = add_delta(416*D - 816*D**2 + 528*D**3 - 144*D**4 + 18*D**5 - D**6) # -128 + assert _is_tensor_eq(tfunc(t), ts) + + t = (G(a1)*G(a2)*G(a3)*G(a4)*G(a5)*G(a6)*G(-a2)*G(-a3)*G(-a1)*G(-a6)*G(-a4)*G(-a5)) + ts = add_delta(416*D - 848*D**2 + 584*D**3 - 172*D**4 + 22*D**5 - D**6) # -128 + assert _is_tensor_eq(tfunc(t), ts) + + # Expressions with free indices: + + t = (G(mu)*G(nu)*G(rho)*G(sigma)*G(-mu)) + assert _is_tensor_eq(tfunc(t), (-2*G(sigma)*G(rho)*G(nu) + (4-D)*G(nu)*G(rho)*G(sigma))) + + t = (G(mu)*G(nu)*G(-mu)) + assert _is_tensor_eq(tfunc(t), (2-D)*G(nu)) + + t = (G(mu)*G(nu)*G(rho)*G(-mu)) + assert _is_tensor_eq(tfunc(t), 2*G(nu)*G(rho) + 2*G(rho)*G(nu) - (4-D)*G(nu)*G(rho)) + + t = 2*G(m2)*G(m0)*G(m1)*G(-m0)*G(-m1) + st = tfunc(t) + assert _is_tensor_eq(st, (D*(-2*D + 4))*G(m2)) + + t = G(m2)*G(m0)*G(m1)*G(-m0)*G(-m2) + st = tfunc(t) + assert _is_tensor_eq(st, ((-D + 2)**2)*G(m1)) + + t = G(m0)*G(m1)*G(m2)*G(m3)*G(-m1) + st = tfunc(t) + assert _is_tensor_eq(st, (D - 4)*G(m0)*G(m2)*G(m3) + 4*G(m0)*g(m2, m3)) + + t = G(m0)*G(m1)*G(m2)*G(m3)*G(-m1)*G(-m0) + st = tfunc(t) + assert _is_tensor_eq(st, ((D - 4)**2)*G(m2)*G(m3) + (8*D - 16)*g(m2, m3)) + + t = G(m2)*G(m0)*G(m1)*G(-m2)*G(-m0) + st = tfunc(t) + assert _is_tensor_eq(st, ((-D + 2)*(D - 4) + 4)*G(m1)) + + t = G(m3)*G(m1)*G(m0)*G(m2)*G(-m3)*G(-m0)*G(-m2) + st = tfunc(t) + assert _is_tensor_eq(st, (-4*D + (-D + 2)**2*(D - 4) + 8)*G(m1)) + + t = 2*G(m0)*G(m1)*G(m2)*G(m3)*G(-m0) + st = tfunc(t) + assert _is_tensor_eq(st, ((-2*D + 8)*G(m1)*G(m2)*G(m3) - 4*G(m3)*G(m2)*G(m1))) + + t = G(m5)*G(m0)*G(m1)*G(m4)*G(m2)*G(-m4)*G(m3)*G(-m0) + st = tfunc(t) + assert _is_tensor_eq(st, (((-D + 2)*(-D + 4))*G(m5)*G(m1)*G(m2)*G(m3) + (2*D - 4)*G(m5)*G(m3)*G(m2)*G(m1))) + + t = -G(m0)*G(m1)*G(m2)*G(m3)*G(-m0)*G(m4) + st = tfunc(t) + assert _is_tensor_eq(st, ((D - 4)*G(m1)*G(m2)*G(m3)*G(m4) + 2*G(m3)*G(m2)*G(m1)*G(m4))) + + t = G(-m5)*G(m0)*G(m1)*G(m2)*G(m3)*G(m4)*G(-m0)*G(m5) + st = tfunc(t) + + result1 = ((-D + 4)**2 + 4)*G(m1)*G(m2)*G(m3)*G(m4) +\ + (4*D - 16)*G(m3)*G(m2)*G(m1)*G(m4) + (4*D - 16)*G(m4)*G(m1)*G(m2)*G(m3)\ + + 4*G(m2)*G(m1)*G(m4)*G(m3) + 4*G(m3)*G(m4)*G(m1)*G(m2) +\ + 4*G(m4)*G(m3)*G(m2)*G(m1) + + # Kahane's algorithm yields this result, which is equivalent to `result1` + # in four dimensions, but is not automatically recognized as equal: + result2 = 8*G(m1)*G(m2)*G(m3)*G(m4) + 8*G(m4)*G(m3)*G(m2)*G(m1) + + if D == 4: + assert _is_tensor_eq(st, (result1)) or _is_tensor_eq(st, (result2)) + else: + assert _is_tensor_eq(st, (result1)) + + # and a few very simple cases, with no contracted indices: + + t = G(m0) + st = tfunc(t) + assert _is_tensor_eq(st, t) + + t = -7*G(m0) + st = tfunc(t) + assert _is_tensor_eq(st, t) + + t = 224*G(m0)*G(m1)*G(-m2)*G(m3) + st = tfunc(t) + assert _is_tensor_eq(st, t) + + +def test_kahane_algorithm(): + # Wrap this function to convert to and from TIDS: + + def tfunc(e): + return _simplify_single_line(e) + + execute_gamma_simplify_tests_for_function(tfunc, D=4) + + +def test_kahane_simplify1(): + i0,i1,i2,i3,i4,i5,i6,i7,i8,i9,i10,i11,i12,i13,i14,i15 = tensor_indices('i0:16', LorentzIndex) + mu, nu, rho, sigma = tensor_indices("mu, nu, rho, sigma", LorentzIndex) + D = 4 + t = G(i0)*G(i1) + r = kahane_simplify(t) + assert r.equals(t) + + t = G(i0)*G(i1)*G(-i0) + r = kahane_simplify(t) + assert r.equals(-2*G(i1)) + t = G(i0)*G(i1)*G(-i0) + r = kahane_simplify(t) + assert r.equals(-2*G(i1)) + + t = G(i0)*G(i1) + r = kahane_simplify(t) + assert r.equals(t) + t = G(i0)*G(i1) + r = kahane_simplify(t) + assert r.equals(t) + t = G(i0)*G(-i0) + r = kahane_simplify(t) + assert r.equals(4*eye(4)) + t = G(i0)*G(-i0) + r = kahane_simplify(t) + assert r.equals(4*eye(4)) + t = G(i0)*G(-i0) + r = kahane_simplify(t) + assert r.equals(4*eye(4)) + t = G(i0)*G(i1)*G(-i0) + r = kahane_simplify(t) + assert r.equals(-2*G(i1)) + t = G(i0)*G(i1)*G(-i0)*G(-i1) + r = kahane_simplify(t) + assert r.equals((2*D - D**2)*eye(4)) + t = G(i0)*G(i1)*G(-i0)*G(-i1) + r = kahane_simplify(t) + assert r.equals((2*D - D**2)*eye(4)) + t = G(i0)*G(-i0)*G(i1)*G(-i1) + r = kahane_simplify(t) + assert r.equals(16*eye(4)) + t = (G(mu)*G(nu)*G(-nu)*G(-mu)) + r = kahane_simplify(t) + assert r.equals(D**2*eye(4)) + t = (G(mu)*G(nu)*G(-nu)*G(-mu)) + r = kahane_simplify(t) + assert r.equals(D**2*eye(4)) + t = (G(mu)*G(nu)*G(-nu)*G(-mu)) + r = kahane_simplify(t) + assert r.equals(D**2*eye(4)) + t = (G(mu)*G(nu)*G(-rho)*G(-nu)*G(-mu)*G(rho)) + r = kahane_simplify(t) + assert r.equals((4*D - 4*D**2 + D**3)*eye(4)) + t = (G(-mu)*G(-nu)*G(-rho)*G(-sigma)*G(nu)*G(mu)*G(sigma)*G(rho)) + r = kahane_simplify(t) + assert r.equals((-16*D + 24*D**2 - 8*D**3 + D**4)*eye(4)) + t = (G(-mu)*G(nu)*G(-rho)*G(sigma)*G(rho)*G(-nu)*G(mu)*G(-sigma)) + r = kahane_simplify(t) + assert r.equals((8*D - 12*D**2 + 6*D**3 - D**4)*eye(4)) + + # Expressions with free indices: + t = (G(mu)*G(nu)*G(rho)*G(sigma)*G(-mu)) + r = kahane_simplify(t) + assert r.equals(-2*G(sigma)*G(rho)*G(nu)) + t = (G(mu)*G(-mu)*G(rho)*G(sigma)) + r = kahane_simplify(t) + assert r.equals(4*G(rho)*G(sigma)) + t = (G(rho)*G(sigma)*G(mu)*G(-mu)) + r = kahane_simplify(t) + assert r.equals(4*G(rho)*G(sigma)) + +def test_gamma_matrix_class(): + i, j, k = tensor_indices('i,j,k', LorentzIndex) + + # define another type of TensorHead to see if exprs are correctly handled: + A = TensorHead('A', [LorentzIndex]) + + t = A(k)*G(i)*G(-i) + ts = simplify_gamma_expression(t) + assert _is_tensor_eq(ts, Matrix([ + [4, 0, 0, 0], + [0, 4, 0, 0], + [0, 0, 4, 0], + [0, 0, 0, 4]])*A(k)) + + t = G(i)*A(k)*G(j) + ts = simplify_gamma_expression(t) + assert _is_tensor_eq(ts, A(k)*G(i)*G(j)) + + execute_gamma_simplify_tests_for_function(simplify_gamma_expression, D=4) + + +def test_gamma_matrix_trace(): + g = LorentzIndex.metric + + m0, m1, m2, m3, m4, m5, m6 = tensor_indices('m0:7', LorentzIndex) + n0, n1, n2, n3, n4, n5 = tensor_indices('n0:6', LorentzIndex) + + # working in D=4 dimensions + D = 4 + + # traces of odd number of gamma matrices are zero: + t = G(m0) + t1 = gamma_trace(t) + assert t1.equals(0) + + t = G(m0)*G(m1)*G(m2) + t1 = gamma_trace(t) + assert t1.equals(0) + + t = G(m0)*G(m1)*G(-m0) + t1 = gamma_trace(t) + assert t1.equals(0) + + t = G(m0)*G(m1)*G(m2)*G(m3)*G(m4) + t1 = gamma_trace(t) + assert t1.equals(0) + + # traces without internal contractions: + t = G(m0)*G(m1) + t1 = gamma_trace(t) + assert _is_tensor_eq(t1, 4*g(m0, m1)) + + t = G(m0)*G(m1)*G(m2)*G(m3) + t1 = gamma_trace(t) + t2 = -4*g(m0, m2)*g(m1, m3) + 4*g(m0, m1)*g(m2, m3) + 4*g(m0, m3)*g(m1, m2) + assert _is_tensor_eq(t1, t2) + + t = G(m0)*G(m1)*G(m2)*G(m3)*G(m4)*G(m5) + t1 = gamma_trace(t) + t2 = t1*g(-m0, -m5) + t2 = t2.contract_metric(g) + assert _is_tensor_eq(t2, D*gamma_trace(G(m1)*G(m2)*G(m3)*G(m4))) + + # traces of expressions with internal contractions: + t = G(m0)*G(-m0) + t1 = gamma_trace(t) + assert t1.equals(4*D) + + t = G(m0)*G(m1)*G(-m0)*G(-m1) + t1 = gamma_trace(t) + assert t1.equals(8*D - 4*D**2) + + t = G(m0)*G(m1)*G(m2)*G(m3)*G(m4)*G(-m0) + t1 = gamma_trace(t) + t2 = (-4*D)*g(m1, m3)*g(m2, m4) + (4*D)*g(m1, m2)*g(m3, m4) + \ + (4*D)*g(m1, m4)*g(m2, m3) + assert _is_tensor_eq(t1, t2) + + t = G(-m5)*G(m0)*G(m1)*G(m2)*G(m3)*G(m4)*G(-m0)*G(m5) + t1 = gamma_trace(t) + t2 = (32*D + 4*(-D + 4)**2 - 64)*(g(m1, m2)*g(m3, m4) - \ + g(m1, m3)*g(m2, m4) + g(m1, m4)*g(m2, m3)) + assert _is_tensor_eq(t1, t2) + + t = G(m0)*G(m1)*G(-m0)*G(m3) + t1 = gamma_trace(t) + assert t1.equals((-4*D + 8)*g(m1, m3)) + +# p, q = S1('p,q') +# ps = p(m0)*G(-m0) +# qs = q(m0)*G(-m0) +# t = ps*qs*ps*qs +# t1 = gamma_trace(t) +# assert t1 == 8*p(m0)*q(-m0)*p(m1)*q(-m1) - 4*p(m0)*p(-m0)*q(m1)*q(-m1) + + t = G(m0)*G(m1)*G(m2)*G(m3)*G(m4)*G(m5)*G(-m0)*G(-m1)*G(-m2)*G(-m3)*G(-m4)*G(-m5) + t1 = gamma_trace(t) + assert t1.equals(-4*D**6 + 120*D**5 - 1040*D**4 + 3360*D**3 - 4480*D**2 + 2048*D) + + t = G(m0)*G(m1)*G(n1)*G(m2)*G(n2)*G(m3)*G(m4)*G(-n2)*G(-n1)*G(-m0)*G(-m1)*G(-m2)*G(-m3)*G(-m4) + t1 = gamma_trace(t) + tresu = -7168*D + 16768*D**2 - 14400*D**3 + 5920*D**4 - 1232*D**5 + 120*D**6 - 4*D**7 + assert t1.equals(tresu) + + # checked with Mathematica + # In[1]:= <o + | | + |<--l(t)--->| + + Examples + ======== + + To construct an actuator, an expression (or symbol) must be supplied to + represent the force it can produce, alongside a pathway specifying its line + of action. Let's also create a global reference frame and spatially fix one + of the points in it while setting the other to be positioned such that it + can freely move in the frame's x direction specified by the coordinate + ``q``. + + >>> from sympy import symbols + >>> from sympy.physics.mechanics import (ForceActuator, LinearPathway, + ... Point, ReferenceFrame) + >>> from sympy.physics.vector import dynamicsymbols + >>> N = ReferenceFrame('N') + >>> q = dynamicsymbols('q') + >>> force = symbols('F') + >>> pA, pB = Point('pA'), Point('pB') + >>> pA.set_vel(N, 0) + >>> pB.set_pos(pA, q*N.x) + >>> pB.pos_from(pA) + q(t)*N.x + >>> linear_pathway = LinearPathway(pA, pB) + >>> actuator = ForceActuator(force, linear_pathway) + >>> actuator + ForceActuator(F, LinearPathway(pA, pB)) + + Parameters + ========== + + force : Expr + The scalar expression defining the (expansile) force that the actuator + produces. + pathway : PathwayBase + The pathway that the actuator follows. This must be an instance of a + concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``. + + """ + + def __init__(self, force, pathway): + """Initializer for ``ForceActuator``. + + Parameters + ========== + + force : Expr + The scalar expression defining the (expansile) force that the + actuator produces. + pathway : PathwayBase + The pathway that the actuator follows. This must be an instance of + a concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``. + + """ + self.force = force + self.pathway = pathway + + @property + def force(self): + """The magnitude of the force produced by the actuator.""" + return self._force + + @force.setter + def force(self, force): + if hasattr(self, '_force'): + msg = ( + f'Can\'t set attribute `force` to {repr(force)} as it is ' + f'immutable.' + ) + raise AttributeError(msg) + self._force = sympify(force, strict=True) + + @property + def pathway(self): + """The ``Pathway`` defining the actuator's line of action.""" + return self._pathway + + @pathway.setter + def pathway(self, pathway): + if hasattr(self, '_pathway'): + msg = ( + f'Can\'t set attribute `pathway` to {repr(pathway)} as it is ' + f'immutable.' + ) + raise AttributeError(msg) + if not isinstance(pathway, PathwayBase): + msg = ( + f'Value {repr(pathway)} passed to `pathway` was of type ' + f'{type(pathway)}, must be {PathwayBase}.' + ) + raise TypeError(msg) + self._pathway = pathway + + def to_loads(self): + """Loads required by the equations of motion method classes. + + Explanation + =========== + + ``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be + passed to the ``loads`` parameters of its ``kanes_equations`` method + when constructing the equations of motion. This method acts as a + utility to produce the correctly-structred pairs of points and vectors + required so that these can be easily concatenated with other items in + the list of loads and passed to ``KanesMethod.kanes_equations``. These + loads are also in the correct form to also be passed to the other + equations of motion method classes, e.g. ``LagrangesMethod``. + + Examples + ======== + + The below example shows how to generate the loads produced by a force + actuator that follows a linear pathway. In this example we'll assume + that the force actuator is being used to model a simple linear spring. + First, create a linear pathway between two points separated by the + coordinate ``q`` in the ``x`` direction of the global frame ``N``. + + >>> from sympy.physics.mechanics import (LinearPathway, Point, + ... ReferenceFrame) + >>> from sympy.physics.vector import dynamicsymbols + >>> q = dynamicsymbols('q') + >>> N = ReferenceFrame('N') + >>> pA, pB = Point('pA'), Point('pB') + >>> pB.set_pos(pA, q*N.x) + >>> pathway = LinearPathway(pA, pB) + + Now create a symbol ``k`` to describe the spring's stiffness and + instantiate a force actuator that produces a (contractile) force + proportional to both the spring's stiffness and the pathway's length. + Note that actuator classes use the sign convention that expansile + forces are positive, so for a spring to produce a contractile force the + spring force needs to be calculated as the negative for the stiffness + multiplied by the length. + + >>> from sympy import symbols + >>> from sympy.physics.mechanics import ForceActuator + >>> stiffness = symbols('k') + >>> spring_force = -stiffness*pathway.length + >>> spring = ForceActuator(spring_force, pathway) + + The forces produced by the spring can be generated in the list of loads + form that ``KanesMethod`` (and other equations of motion methods) + requires by calling the ``to_loads`` method. + + >>> spring.to_loads() + [(pA, k*q(t)*N.x), (pB, - k*q(t)*N.x)] + + A simple linear damper can be modeled in a similar way. Create another + symbol ``c`` to describe the dampers damping coefficient. This time + instantiate a force actuator that produces a force proportional to both + the damper's damping coefficient and the pathway's extension velocity. + Note that the damping force is negative as it acts in the opposite + direction to which the damper is changing in length. + + >>> damping_coefficient = symbols('c') + >>> damping_force = -damping_coefficient*pathway.extension_velocity + >>> damper = ForceActuator(damping_force, pathway) + + Again, the forces produces by the damper can be generated by calling + the ``to_loads`` method. + + >>> damper.to_loads() + [(pA, c*Derivative(q(t), t)*N.x), (pB, - c*Derivative(q(t), t)*N.x)] + + """ + return self.pathway.to_loads(self.force) + + def __repr__(self): + """Representation of a ``ForceActuator``.""" + return f'{self.__class__.__name__}({self.force}, {self.pathway})' + + +class LinearSpring(ForceActuator): + """A spring with its spring force as a linear function of its length. + + Explanation + =========== + + Note that the "linear" in the name ``LinearSpring`` refers to the fact that + the spring force is a linear function of the springs length. I.e. for a + linear spring with stiffness ``k``, distance between its ends of ``x``, and + an equilibrium length of ``0``, the spring force will be ``-k*x``, which is + a linear function in ``x``. To create a spring that follows a linear, or + straight, pathway between its two ends, a ``LinearPathway`` instance needs + to be passed to the ``pathway`` parameter. + + A ``LinearSpring`` is a subclass of ``ForceActuator`` and so follows the + same sign conventions for length, extension velocity, and the direction of + the forces it applies to its points of attachment on bodies. The sign + convention for the direction of forces is such that, for the case where a + linear spring is instantiated with a ``LinearPathway`` instance as its + pathway, they act to push the two ends of the spring away from one another. + Because springs produces a contractile force and acts to pull the two ends + together towards the equilibrium length when stretched, the scalar portion + of the forces on the endpoint are negative in order to flip the sign of the + forces on the endpoints when converted into vector quantities. The + following diagram shows the positive force sense and the distance between + the points:: + + P Q + o<--- F --->o + | | + |<--l(t)--->| + + Examples + ======== + + To construct a linear spring, an expression (or symbol) must be supplied to + represent the stiffness (spring constant) of the spring, alongside a + pathway specifying its line of action. Let's also create a global reference + frame and spatially fix one of the points in it while setting the other to + be positioned such that it can freely move in the frame's x direction + specified by the coordinate ``q``. + + >>> from sympy import symbols + >>> from sympy.physics.mechanics import (LinearPathway, LinearSpring, + ... Point, ReferenceFrame) + >>> from sympy.physics.vector import dynamicsymbols + >>> N = ReferenceFrame('N') + >>> q = dynamicsymbols('q') + >>> stiffness = symbols('k') + >>> pA, pB = Point('pA'), Point('pB') + >>> pA.set_vel(N, 0) + >>> pB.set_pos(pA, q*N.x) + >>> pB.pos_from(pA) + q(t)*N.x + >>> linear_pathway = LinearPathway(pA, pB) + >>> spring = LinearSpring(stiffness, linear_pathway) + >>> spring + LinearSpring(k, LinearPathway(pA, pB)) + + This spring will produce a force that is proportional to both its stiffness + and the pathway's length. Note that this force is negative as SymPy's sign + convention for actuators is that negative forces are contractile. + + >>> spring.force + -k*sqrt(q(t)**2) + + To create a linear spring with a non-zero equilibrium length, an expression + (or symbol) can be passed to the ``equilibrium_length`` parameter on + construction on a ``LinearSpring`` instance. Let's create a symbol ``l`` + to denote a non-zero equilibrium length and create another linear spring. + + >>> l = symbols('l') + >>> spring = LinearSpring(stiffness, linear_pathway, equilibrium_length=l) + >>> spring + LinearSpring(k, LinearPathway(pA, pB), equilibrium_length=l) + + The spring force of this new spring is again proportional to both its + stiffness and the pathway's length. However, the spring will not produce + any force when ``q(t)`` equals ``l``. Note that the force will become + expansile when ``q(t)`` is less than ``l``, as expected. + + >>> spring.force + -k*(-l + sqrt(q(t)**2)) + + Parameters + ========== + + stiffness : Expr + The spring constant. + pathway : PathwayBase + The pathway that the actuator follows. This must be an instance of a + concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``. + equilibrium_length : Expr, optional + The length at which the spring is in equilibrium, i.e. it produces no + force. The default value is 0, i.e. the spring force is a linear + function of the pathway's length with no constant offset. + + See Also + ======== + + ForceActuator: force-producing actuator (superclass of ``LinearSpring``). + LinearPathway: straight-line pathway between a pair of points. + + """ + + def __init__(self, stiffness, pathway, equilibrium_length=S.Zero): + """Initializer for ``LinearSpring``. + + Parameters + ========== + + stiffness : Expr + The spring constant. + pathway : PathwayBase + The pathway that the actuator follows. This must be an instance of + a concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``. + equilibrium_length : Expr, optional + The length at which the spring is in equilibrium, i.e. it produces + no force. The default value is 0, i.e. the spring force is a linear + function of the pathway's length with no constant offset. + + """ + self.stiffness = stiffness + self.pathway = pathway + self.equilibrium_length = equilibrium_length + + @property + def force(self): + """The spring force produced by the linear spring.""" + return -self.stiffness*(self.pathway.length - self.equilibrium_length) + + @force.setter + def force(self, force): + raise AttributeError('Can\'t set computed attribute `force`.') + + @property + def stiffness(self): + """The spring constant for the linear spring.""" + return self._stiffness + + @stiffness.setter + def stiffness(self, stiffness): + if hasattr(self, '_stiffness'): + msg = ( + f'Can\'t set attribute `stiffness` to {repr(stiffness)} as it ' + f'is immutable.' + ) + raise AttributeError(msg) + self._stiffness = sympify(stiffness, strict=True) + + @property + def equilibrium_length(self): + """The length of the spring at which it produces no force.""" + return self._equilibrium_length + + @equilibrium_length.setter + def equilibrium_length(self, equilibrium_length): + if hasattr(self, '_equilibrium_length'): + msg = ( + f'Can\'t set attribute `equilibrium_length` to ' + f'{repr(equilibrium_length)} as it is immutable.' + ) + raise AttributeError(msg) + self._equilibrium_length = sympify(equilibrium_length, strict=True) + + def __repr__(self): + """Representation of a ``LinearSpring``.""" + string = f'{self.__class__.__name__}({self.stiffness}, {self.pathway}' + if self.equilibrium_length == S.Zero: + string += ')' + else: + string += f', equilibrium_length={self.equilibrium_length})' + return string + + +class LinearDamper(ForceActuator): + """A damper whose force is a linear function of its extension velocity. + + Explanation + =========== + + Note that the "linear" in the name ``LinearDamper`` refers to the fact that + the damping force is a linear function of the damper's rate of change in + its length. I.e. for a linear damper with damping ``c`` and extension + velocity ``v``, the damping force will be ``-c*v``, which is a linear + function in ``v``. To create a damper that follows a linear, or straight, + pathway between its two ends, a ``LinearPathway`` instance needs to be + passed to the ``pathway`` parameter. + + A ``LinearDamper`` is a subclass of ``ForceActuator`` and so follows the + same sign conventions for length, extension velocity, and the direction of + the forces it applies to its points of attachment on bodies. The sign + convention for the direction of forces is such that, for the case where a + linear damper is instantiated with a ``LinearPathway`` instance as its + pathway, they act to push the two ends of the damper away from one another. + Because dampers produce a force that opposes the direction of change in + length, when extension velocity is positive the scalar portions of the + forces applied at the two endpoints are negative in order to flip the sign + of the forces on the endpoints wen converted into vector quantities. When + extension velocity is negative (i.e. when the damper is shortening), the + scalar portions of the fofces applied are also negative so that the signs + cancel producing forces on the endpoints that are in the same direction as + the positive sign convention for the forces at the endpoints of the pathway + (i.e. they act to push the endpoints away from one another). The following + diagram shows the positive force sense and the distance between the + points:: + + P Q + o<--- F --->o + | | + |<--l(t)--->| + + Examples + ======== + + To construct a linear damper, an expression (or symbol) must be supplied to + represent the damping coefficient of the damper (we'll use the symbol + ``c``), alongside a pathway specifying its line of action. Let's also + create a global reference frame and spatially fix one of the points in it + while setting the other to be positioned such that it can freely move in + the frame's x direction specified by the coordinate ``q``. The velocity + that the two points move away from one another can be specified by the + coordinate ``u`` where ``u`` is the first time derivative of ``q`` + (i.e., ``u = Derivative(q(t), t)``). + + >>> from sympy import symbols + >>> from sympy.physics.mechanics import (LinearDamper, LinearPathway, + ... Point, ReferenceFrame) + >>> from sympy.physics.vector import dynamicsymbols + >>> N = ReferenceFrame('N') + >>> q = dynamicsymbols('q') + >>> damping = symbols('c') + >>> pA, pB = Point('pA'), Point('pB') + >>> pA.set_vel(N, 0) + >>> pB.set_pos(pA, q*N.x) + >>> pB.pos_from(pA) + q(t)*N.x + >>> pB.vel(N) + Derivative(q(t), t)*N.x + >>> linear_pathway = LinearPathway(pA, pB) + >>> damper = LinearDamper(damping, linear_pathway) + >>> damper + LinearDamper(c, LinearPathway(pA, pB)) + + This damper will produce a force that is proportional to both its damping + coefficient and the pathway's extension length. Note that this force is + negative as SymPy's sign convention for actuators is that negative forces + are contractile and the damping force of the damper will oppose the + direction of length change. + + >>> damper.force + -c*sqrt(q(t)**2)*Derivative(q(t), t)/q(t) + + Parameters + ========== + + damping : Expr + The damping constant. + pathway : PathwayBase + The pathway that the actuator follows. This must be an instance of a + concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``. + + See Also + ======== + + ForceActuator: force-producing actuator (superclass of ``LinearDamper``). + LinearPathway: straight-line pathway between a pair of points. + + """ + + def __init__(self, damping, pathway): + """Initializer for ``LinearDamper``. + + Parameters + ========== + + damping : Expr + The damping constant. + pathway : PathwayBase + The pathway that the actuator follows. This must be an instance of + a concrete subclass of ``PathwayBase``, e.g. ``LinearPathway``. + + """ + self.damping = damping + self.pathway = pathway + + @property + def force(self): + """The damping force produced by the linear damper.""" + return -self.damping*self.pathway.extension_velocity + + @force.setter + def force(self, force): + raise AttributeError('Can\'t set computed attribute `force`.') + + @property + def damping(self): + """The damping constant for the linear damper.""" + return self._damping + + @damping.setter + def damping(self, damping): + if hasattr(self, '_damping'): + msg = ( + f'Can\'t set attribute `damping` to {repr(damping)} as it is ' + f'immutable.' + ) + raise AttributeError(msg) + self._damping = sympify(damping, strict=True) + + def __repr__(self): + """Representation of a ``LinearDamper``.""" + return f'{self.__class__.__name__}({self.damping}, {self.pathway})' + + +class TorqueActuator(ActuatorBase): + """Torque-producing actuator. + + Explanation + =========== + + A ``TorqueActuator`` is an actuator that produces a pair of equal and + opposite torques on a pair of bodies. + + Examples + ======== + + To construct a torque actuator, an expression (or symbol) must be supplied + to represent the torque it can produce, alongside a vector specifying the + axis about which the torque will act, and a pair of frames on which the + torque will act. + + >>> from sympy import symbols + >>> from sympy.physics.mechanics import (ReferenceFrame, RigidBody, + ... TorqueActuator) + >>> N = ReferenceFrame('N') + >>> A = ReferenceFrame('A') + >>> torque = symbols('T') + >>> axis = N.z + >>> parent = RigidBody('parent', frame=N) + >>> child = RigidBody('child', frame=A) + >>> bodies = (child, parent) + >>> actuator = TorqueActuator(torque, axis, *bodies) + >>> actuator + TorqueActuator(T, axis=N.z, target_frame=A, reaction_frame=N) + + Note that because torques actually act on frames, not bodies, + ``TorqueActuator`` will extract the frame associated with a ``RigidBody`` + when one is passed instead of a ``ReferenceFrame``. + + Parameters + ========== + + torque : Expr + The scalar expression defining the torque that the actuator produces. + axis : Vector + The axis about which the actuator applies torques. + target_frame : ReferenceFrame | RigidBody + The primary frame on which the actuator will apply the torque. + reaction_frame : ReferenceFrame | RigidBody | None + The secondary frame on which the actuator will apply the torque. Note + that the (equal and opposite) reaction torque is applied to this frame. + + """ + + def __init__(self, torque, axis, target_frame, reaction_frame=None): + """Initializer for ``TorqueActuator``. + + Parameters + ========== + + torque : Expr + The scalar expression defining the torque that the actuator + produces. + axis : Vector + The axis about which the actuator applies torques. + target_frame : ReferenceFrame | RigidBody + The primary frame on which the actuator will apply the torque. + reaction_frame : ReferenceFrame | RigidBody | None + The secondary frame on which the actuator will apply the torque. + Note that the (equal and opposite) reaction torque is applied to + this frame. + + """ + self.torque = torque + self.axis = axis + self.target_frame = target_frame + self.reaction_frame = reaction_frame + + @classmethod + def at_pin_joint(cls, torque, pin_joint): + """Alternate construtor to instantiate from a ``PinJoint`` instance. + + Examples + ======== + + To create a pin joint the ``PinJoint`` class requires a name, parent + body, and child body to be passed to its constructor. It is also + possible to control the joint axis using the ``joint_axis`` keyword + argument. In this example let's use the parent body's reference frame's + z-axis as the joint axis. + + >>> from sympy.physics.mechanics import (PinJoint, ReferenceFrame, + ... RigidBody, TorqueActuator) + >>> N = ReferenceFrame('N') + >>> A = ReferenceFrame('A') + >>> parent = RigidBody('parent', frame=N) + >>> child = RigidBody('child', frame=A) + >>> pin_joint = PinJoint( + ... 'pin', + ... parent, + ... child, + ... joint_axis=N.z, + ... ) + + Let's also create a symbol ``T`` that will represent the torque applied + by the torque actuator. + + >>> from sympy import symbols + >>> torque = symbols('T') + + To create the torque actuator from the ``torque`` and ``pin_joint`` + variables previously instantiated, these can be passed to the alternate + constructor class method ``at_pin_joint`` of the ``TorqueActuator`` + class. It should be noted that a positive torque will cause a positive + displacement of the joint coordinate or that the torque is applied on + the child body with a reaction torque on the parent. + + >>> actuator = TorqueActuator.at_pin_joint(torque, pin_joint) + >>> actuator + TorqueActuator(T, axis=N.z, target_frame=A, reaction_frame=N) + + Parameters + ========== + + torque : Expr + The scalar expression defining the torque that the actuator + produces. + pin_joint : PinJoint + The pin joint, and by association the parent and child bodies, on + which the torque actuator will act. The pair of bodies acted upon + by the torque actuator are the parent and child bodies of the pin + joint, with the child acting as the reaction body. The pin joint's + axis is used as the axis about which the torque actuator will apply + its torque. + + """ + if not isinstance(pin_joint, PinJoint): + msg = ( + f'Value {repr(pin_joint)} passed to `pin_joint` was of type ' + f'{type(pin_joint)}, must be {PinJoint}.' + ) + raise TypeError(msg) + return cls( + torque, + pin_joint.joint_axis, + pin_joint.child_interframe, + pin_joint.parent_interframe, + ) + + @property + def torque(self): + """The magnitude of the torque produced by the actuator.""" + return self._torque + + @torque.setter + def torque(self, torque): + if hasattr(self, '_torque'): + msg = ( + f'Can\'t set attribute `torque` to {repr(torque)} as it is ' + f'immutable.' + ) + raise AttributeError(msg) + self._torque = sympify(torque, strict=True) + + @property + def axis(self): + """The axis about which the torque acts.""" + return self._axis + + @axis.setter + def axis(self, axis): + if hasattr(self, '_axis'): + msg = ( + f'Can\'t set attribute `axis` to {repr(axis)} as it is ' + f'immutable.' + ) + raise AttributeError(msg) + if not isinstance(axis, Vector): + msg = ( + f'Value {repr(axis)} passed to `axis` was of type ' + f'{type(axis)}, must be {Vector}.' + ) + raise TypeError(msg) + self._axis = axis + + @property + def target_frame(self): + """The primary reference frames on which the torque will act.""" + return self._target_frame + + @target_frame.setter + def target_frame(self, target_frame): + if hasattr(self, '_target_frame'): + msg = ( + f'Can\'t set attribute `target_frame` to {repr(target_frame)} ' + f'as it is immutable.' + ) + raise AttributeError(msg) + if isinstance(target_frame, RigidBody): + target_frame = target_frame.frame + elif not isinstance(target_frame, ReferenceFrame): + msg = ( + f'Value {repr(target_frame)} passed to `target_frame` was of ' + f'type {type(target_frame)}, must be {ReferenceFrame}.' + ) + raise TypeError(msg) + self._target_frame = target_frame + + @property + def reaction_frame(self): + """The primary reference frames on which the torque will act.""" + return self._reaction_frame + + @reaction_frame.setter + def reaction_frame(self, reaction_frame): + if hasattr(self, '_reaction_frame'): + msg = ( + f'Can\'t set attribute `reaction_frame` to ' + f'{repr(reaction_frame)} as it is immutable.' + ) + raise AttributeError(msg) + if isinstance(reaction_frame, RigidBody): + reaction_frame = reaction_frame.frame + elif ( + not isinstance(reaction_frame, ReferenceFrame) + and reaction_frame is not None + ): + msg = ( + f'Value {repr(reaction_frame)} passed to `reaction_frame` was ' + f'of type {type(reaction_frame)}, must be {ReferenceFrame}.' + ) + raise TypeError(msg) + self._reaction_frame = reaction_frame + + def to_loads(self): + """Loads required by the equations of motion method classes. + + Explanation + =========== + + ``KanesMethod`` requires a list of ``Point``-``Vector`` tuples to be + passed to the ``loads`` parameters of its ``kanes_equations`` method + when constructing the equations of motion. This method acts as a + utility to produce the correctly-structred pairs of points and vectors + required so that these can be easily concatenated with other items in + the list of loads and passed to ``KanesMethod.kanes_equations``. These + loads are also in the correct form to also be passed to the other + equations of motion method classes, e.g. ``LagrangesMethod``. + + Examples + ======== + + The below example shows how to generate the loads produced by a torque + actuator that acts on a pair of bodies attached by a pin joint. + + >>> from sympy import symbols + >>> from sympy.physics.mechanics import (PinJoint, ReferenceFrame, + ... RigidBody, TorqueActuator) + >>> torque = symbols('T') + >>> N = ReferenceFrame('N') + >>> A = ReferenceFrame('A') + >>> parent = RigidBody('parent', frame=N) + >>> child = RigidBody('child', frame=A) + >>> pin_joint = PinJoint( + ... 'pin', + ... parent, + ... child, + ... joint_axis=N.z, + ... ) + >>> actuator = TorqueActuator.at_pin_joint(torque, pin_joint) + + The forces produces by the damper can be generated by calling the + ``to_loads`` method. + + >>> actuator.to_loads() + [(A, T*N.z), (N, - T*N.z)] + + Alternatively, if a torque actuator is created without a reaction frame + then the loads returned by the ``to_loads`` method will contain just + the single load acting on the target frame. + + >>> actuator = TorqueActuator(torque, N.z, N) + >>> actuator.to_loads() + [(N, T*N.z)] + + """ + loads = [ + Torque(self.target_frame, self.torque*self.axis), + ] + if self.reaction_frame is not None: + loads.append(Torque(self.reaction_frame, -self.torque*self.axis)) + return loads + + def __repr__(self): + """Representation of a ``TorqueActuator``.""" + string = ( + f'{self.__class__.__name__}({self.torque}, axis={self.axis}, ' + f'target_frame={self.target_frame}' + ) + if self.reaction_frame is not None: + string += f', reaction_frame={self.reaction_frame})' + else: + string += ')' + return string + + +class DuffingSpring(ForceActuator): + """A nonlinear spring based on the Duffing equation. + + Explanation + =========== + + Here, ``DuffingSpring`` represents the force exerted by a nonlinear spring based on the Duffing equation: + F = -beta*x-alpha*x**3, where x is the displacement from the equilibrium position, beta is the linear spring constant, + and alpha is the coefficient for the nonlinear cubic term. + + Parameters + ========== + + linear_stiffness : Expr + The linear stiffness coefficient (beta). + nonlinear_stiffness : Expr + The nonlinear stiffness coefficient (alpha). + pathway : PathwayBase + The pathway that the actuator follows. + equilibrium_length : Expr, optional + The length at which the spring is in equilibrium (x). + """ + + def __init__(self, linear_stiffness, nonlinear_stiffness, pathway, equilibrium_length=S.Zero): + self.linear_stiffness = sympify(linear_stiffness, strict=True) + self.nonlinear_stiffness = sympify(nonlinear_stiffness, strict=True) + self.equilibrium_length = sympify(equilibrium_length, strict=True) + + if not isinstance(pathway, PathwayBase): + raise TypeError("pathway must be an instance of PathwayBase.") + self._pathway = pathway + + @property + def linear_stiffness(self): + return self._linear_stiffness + + @linear_stiffness.setter + def linear_stiffness(self, linear_stiffness): + if hasattr(self, '_linear_stiffness'): + msg = ( + f'Can\'t set attribute `linear_stiffness` to ' + f'{repr(linear_stiffness)} as it is immutable.' + ) + raise AttributeError(msg) + self._linear_stiffness = sympify(linear_stiffness, strict=True) + + @property + def nonlinear_stiffness(self): + return self._nonlinear_stiffness + + @nonlinear_stiffness.setter + def nonlinear_stiffness(self, nonlinear_stiffness): + if hasattr(self, '_nonlinear_stiffness'): + msg = ( + f'Can\'t set attribute `nonlinear_stiffness` to ' + f'{repr(nonlinear_stiffness)} as it is immutable.' + ) + raise AttributeError(msg) + self._nonlinear_stiffness = sympify(nonlinear_stiffness, strict=True) + + @property + def pathway(self): + return self._pathway + + @pathway.setter + def pathway(self, pathway): + if hasattr(self, '_pathway'): + msg = ( + f'Can\'t set attribute `pathway` to {repr(pathway)} as it is ' + f'immutable.' + ) + raise AttributeError(msg) + if not isinstance(pathway, PathwayBase): + msg = ( + f'Value {repr(pathway)} passed to `pathway` was of type ' + f'{type(pathway)}, must be {PathwayBase}.' + ) + raise TypeError(msg) + self._pathway = pathway + + @property + def equilibrium_length(self): + return self._equilibrium_length + + @equilibrium_length.setter + def equilibrium_length(self, equilibrium_length): + if hasattr(self, '_equilibrium_length'): + msg = ( + f'Can\'t set attribute `equilibrium_length` to ' + f'{repr(equilibrium_length)} as it is immutable.' + ) + raise AttributeError(msg) + self._equilibrium_length = sympify(equilibrium_length, strict=True) + + @property + def force(self): + """The force produced by the Duffing spring.""" + displacement = self.pathway.length - self.equilibrium_length + return -self.linear_stiffness * displacement - self.nonlinear_stiffness * displacement**3 + + @force.setter + def force(self, force): + if hasattr(self, '_force'): + msg = ( + f'Can\'t set attribute `force` to {repr(force)} as it is ' + f'immutable.' + ) + raise AttributeError(msg) + self._force = sympify(force, strict=True) + + def __repr__(self): + return (f"{self.__class__.__name__}(" + f"{self.linear_stiffness}, {self.nonlinear_stiffness}, {self.pathway}, " + f"equilibrium_length={self.equilibrium_length})") diff --git a/lib/python3.12/site-packages/sympy/physics/mechanics/body.py b/lib/python3.12/site-packages/sympy/physics/mechanics/body.py new file mode 100644 index 0000000000000000000000000000000000000000..efc367158bbf51e7d9929318ac9286ba5c3fb3ac --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/mechanics/body.py @@ -0,0 +1,710 @@ +from sympy import Symbol +from sympy.physics.vector import Point, Vector, ReferenceFrame, Dyadic +from sympy.physics.mechanics import RigidBody, Particle, Inertia +from sympy.physics.mechanics.body_base import BodyBase +from sympy.utilities.exceptions import sympy_deprecation_warning + +__all__ = ['Body'] + + +# XXX: We use type:ignore because the classes RigidBody and Particle have +# inconsistent parallel axis methods that take different numbers of arguments. +class Body(RigidBody, Particle): # type: ignore + """ + Body is a common representation of either a RigidBody or a Particle SymPy + object depending on what is passed in during initialization. If a mass is + passed in and central_inertia is left as None, the Particle object is + created. Otherwise a RigidBody object will be created. + + .. deprecated:: 1.13 + The Body class is deprecated. Its functionality is captured by + :class:`~.RigidBody` and :class:`~.Particle`. + + Explanation + =========== + + The attributes that Body possesses will be the same as a Particle instance + or a Rigid Body instance depending on which was created. Additional + attributes are listed below. + + Attributes + ========== + + name : string + The body's name + masscenter : Point + The point which represents the center of mass of the rigid body + frame : ReferenceFrame + The reference frame which the body is fixed in + mass : Sympifyable + The body's mass + inertia : (Dyadic, Point) + The body's inertia around its center of mass. This attribute is specific + to the rigid body form of Body and is left undefined for the Particle + form + loads : iterable + This list contains information on the different loads acting on the + Body. Forces are listed as a (point, vector) tuple and torques are + listed as (reference frame, vector) tuples. + + Parameters + ========== + + name : String + Defines the name of the body. It is used as the base for defining + body specific properties. + masscenter : Point, optional + A point that represents the center of mass of the body or particle. + If no point is given, a point is generated. + mass : Sympifyable, optional + A Sympifyable object which represents the mass of the body. If no + mass is passed, one is generated. + frame : ReferenceFrame, optional + The ReferenceFrame that represents the reference frame of the body. + If no frame is given, a frame is generated. + central_inertia : Dyadic, optional + Central inertia dyadic of the body. If none is passed while creating + RigidBody, a default inertia is generated. + + Examples + ======== + + As Body has been deprecated, the following examples are for illustrative + purposes only. The functionality of Body is fully captured by + :class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation + warning we can use the ignore_warnings context manager. + + >>> from sympy.utilities.exceptions import ignore_warnings + + Default behaviour. This results in the creation of a RigidBody object for + which the mass, mass center, frame and inertia attributes are given default + values. :: + + >>> from sympy.physics.mechanics import Body + >>> with ignore_warnings(DeprecationWarning): + ... body = Body('name_of_body') + + This next example demonstrates the code required to specify all of the + values of the Body object. Note this will also create a RigidBody version of + the Body object. :: + + >>> from sympy import Symbol + >>> from sympy.physics.mechanics import ReferenceFrame, Point, inertia + >>> from sympy.physics.mechanics import Body + >>> mass = Symbol('mass') + >>> masscenter = Point('masscenter') + >>> frame = ReferenceFrame('frame') + >>> ixx = Symbol('ixx') + >>> body_inertia = inertia(frame, ixx, 0, 0) + >>> with ignore_warnings(DeprecationWarning): + ... body = Body('name_of_body', masscenter, mass, frame, body_inertia) + + The minimal code required to create a Particle version of the Body object + involves simply passing in a name and a mass. :: + + >>> from sympy import Symbol + >>> from sympy.physics.mechanics import Body + >>> mass = Symbol('mass') + >>> with ignore_warnings(DeprecationWarning): + ... body = Body('name_of_body', mass=mass) + + The Particle version of the Body object can also receive a masscenter point + and a reference frame, just not an inertia. + """ + + def __init__(self, name, masscenter=None, mass=None, frame=None, + central_inertia=None): + sympy_deprecation_warning( + """ + Support for the Body class has been removed, as its functionality is + fully captured by RigidBody and Particle. + """, + deprecated_since_version="1.13", + active_deprecations_target="deprecated-mechanics-body-class" + ) + + self._loads = [] + + if frame is None: + frame = ReferenceFrame(name + '_frame') + + if masscenter is None: + masscenter = Point(name + '_masscenter') + + if central_inertia is None and mass is None: + ixx = Symbol(name + '_ixx') + iyy = Symbol(name + '_iyy') + izz = Symbol(name + '_izz') + izx = Symbol(name + '_izx') + ixy = Symbol(name + '_ixy') + iyz = Symbol(name + '_iyz') + _inertia = Inertia.from_inertia_scalars(masscenter, frame, ixx, iyy, + izz, ixy, iyz, izx) + else: + _inertia = (central_inertia, masscenter) + + if mass is None: + _mass = Symbol(name + '_mass') + else: + _mass = mass + + masscenter.set_vel(frame, 0) + + # If user passes masscenter and mass then a particle is created + # otherwise a rigidbody. As a result a body may or may not have inertia. + # Note: BodyBase.__init__ is used to prevent problems with super() calls in + # Particle and RigidBody arising due to multiple inheritance. + if central_inertia is None and mass is not None: + BodyBase.__init__(self, name, masscenter, _mass) + self.frame = frame + self._central_inertia = Dyadic(0) + else: + BodyBase.__init__(self, name, masscenter, _mass) + self.frame = frame + self.inertia = _inertia + + def __repr__(self): + if self.is_rigidbody: + return RigidBody.__repr__(self) + return Particle.__repr__(self) + + @property + def loads(self): + return self._loads + + @property + def x(self): + """The basis Vector for the Body, in the x direction.""" + return self.frame.x + + @property + def y(self): + """The basis Vector for the Body, in the y direction.""" + return self.frame.y + + @property + def z(self): + """The basis Vector for the Body, in the z direction.""" + return self.frame.z + + @property + def inertia(self): + """The body's inertia about a point; stored as (Dyadic, Point).""" + if self.is_rigidbody: + return RigidBody.inertia.fget(self) + return (self.central_inertia, self.masscenter) + + @inertia.setter + def inertia(self, I): + RigidBody.inertia.fset(self, I) + + @property + def is_rigidbody(self): + if hasattr(self, '_inertia'): + return True + return False + + def kinetic_energy(self, frame): + """Kinetic energy of the body. + + Parameters + ========== + + frame : ReferenceFrame or Body + The Body's angular velocity and the velocity of it's mass + center are typically defined with respect to an inertial frame but + any relevant frame in which the velocities are known can be supplied. + + Examples + ======== + + As Body has been deprecated, the following examples are for illustrative + purposes only. The functionality of Body is fully captured by + :class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation + warning we can use the ignore_warnings context manager. + + >>> from sympy.utilities.exceptions import ignore_warnings + >>> from sympy.physics.mechanics import Body, ReferenceFrame, Point + >>> from sympy import symbols + >>> m, v, r, omega = symbols('m v r omega') + >>> N = ReferenceFrame('N') + >>> O = Point('O') + >>> with ignore_warnings(DeprecationWarning): + ... P = Body('P', masscenter=O, mass=m) + >>> P.masscenter.set_vel(N, v * N.y) + >>> P.kinetic_energy(N) + m*v**2/2 + + >>> N = ReferenceFrame('N') + >>> b = ReferenceFrame('b') + >>> b.set_ang_vel(N, omega * b.x) + >>> P = Point('P') + >>> P.set_vel(N, v * N.x) + >>> with ignore_warnings(DeprecationWarning): + ... B = Body('B', masscenter=P, frame=b) + >>> B.kinetic_energy(N) + B_ixx*omega**2/2 + B_mass*v**2/2 + + See Also + ======== + + sympy.physics.mechanics : Particle, RigidBody + + """ + if isinstance(frame, Body): + frame = Body.frame + if self.is_rigidbody: + return RigidBody(self.name, self.masscenter, self.frame, self.mass, + (self.central_inertia, self.masscenter)).kinetic_energy(frame) + return Particle(self.name, self.masscenter, self.mass).kinetic_energy(frame) + + def apply_force(self, force, point=None, reaction_body=None, reaction_point=None): + """Add force to the body(s). + + Explanation + =========== + + Applies the force on self or equal and opposite forces on + self and other body if both are given on the desired point on the bodies. + The force applied on other body is taken opposite of self, i.e, -force. + + Parameters + ========== + + force: Vector + The force to be applied. + point: Point, optional + The point on self on which force is applied. + By default self's masscenter. + reaction_body: Body, optional + Second body on which equal and opposite force + is to be applied. + reaction_point : Point, optional + The point on other body on which equal and opposite + force is applied. By default masscenter of other body. + + Example + ======= + + As Body has been deprecated, the following examples are for illustrative + purposes only. The functionality of Body is fully captured by + :class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation + warning we can use the ignore_warnings context manager. + + >>> from sympy.utilities.exceptions import ignore_warnings + >>> from sympy import symbols + >>> from sympy.physics.mechanics import Body, Point, dynamicsymbols + >>> m, g = symbols('m g') + >>> with ignore_warnings(DeprecationWarning): + ... B = Body('B') + >>> force1 = m*g*B.z + >>> B.apply_force(force1) #Applying force on B's masscenter + >>> B.loads + [(B_masscenter, g*m*B_frame.z)] + + We can also remove some part of force from any point on the body by + adding the opposite force to the body on that point. + + >>> f1, f2 = dynamicsymbols('f1 f2') + >>> P = Point('P') #Considering point P on body B + >>> B.apply_force(f1*B.x + f2*B.y, P) + >>> B.loads + [(B_masscenter, g*m*B_frame.z), (P, f1(t)*B_frame.x + f2(t)*B_frame.y)] + + Let's remove f1 from point P on body B. + + >>> B.apply_force(-f1*B.x, P) + >>> B.loads + [(B_masscenter, g*m*B_frame.z), (P, f2(t)*B_frame.y)] + + To further demonstrate the use of ``apply_force`` attribute, + consider two bodies connected through a spring. + + >>> from sympy.physics.mechanics import Body, dynamicsymbols + >>> with ignore_warnings(DeprecationWarning): + ... N = Body('N') #Newtonion Frame + >>> x = dynamicsymbols('x') + >>> with ignore_warnings(DeprecationWarning): + ... B1 = Body('B1') + ... B2 = Body('B2') + >>> spring_force = x*N.x + + Now let's apply equal and opposite spring force to the bodies. + + >>> P1 = Point('P1') + >>> P2 = Point('P2') + >>> B1.apply_force(spring_force, point=P1, reaction_body=B2, reaction_point=P2) + + We can check the loads(forces) applied to bodies now. + + >>> B1.loads + [(P1, x(t)*N_frame.x)] + >>> B2.loads + [(P2, - x(t)*N_frame.x)] + + Notes + ===== + + If a new force is applied to a body on a point which already has some + force applied on it, then the new force is added to the already applied + force on that point. + + """ + + if not isinstance(point, Point): + if point is None: + point = self.masscenter # masscenter + else: + raise TypeError("Force must be applied to a point on the body.") + if not isinstance(force, Vector): + raise TypeError("Force must be a vector.") + + if reaction_body is not None: + reaction_body.apply_force(-force, point=reaction_point) + + for load in self._loads: + if point in load: + force += load[1] + self._loads.remove(load) + break + + self._loads.append((point, force)) + + def apply_torque(self, torque, reaction_body=None): + """Add torque to the body(s). + + Explanation + =========== + + Applies the torque on self or equal and opposite torques on + self and other body if both are given. + The torque applied on other body is taken opposite of self, + i.e, -torque. + + Parameters + ========== + + torque: Vector + The torque to be applied. + reaction_body: Body, optional + Second body on which equal and opposite torque + is to be applied. + + Example + ======= + + As Body has been deprecated, the following examples are for illustrative + purposes only. The functionality of Body is fully captured by + :class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation + warning we can use the ignore_warnings context manager. + + >>> from sympy.utilities.exceptions import ignore_warnings + >>> from sympy import symbols + >>> from sympy.physics.mechanics import Body, dynamicsymbols + >>> t = symbols('t') + >>> with ignore_warnings(DeprecationWarning): + ... B = Body('B') + >>> torque1 = t*B.z + >>> B.apply_torque(torque1) + >>> B.loads + [(B_frame, t*B_frame.z)] + + We can also remove some part of torque from the body by + adding the opposite torque to the body. + + >>> t1, t2 = dynamicsymbols('t1 t2') + >>> B.apply_torque(t1*B.x + t2*B.y) + >>> B.loads + [(B_frame, t1(t)*B_frame.x + t2(t)*B_frame.y + t*B_frame.z)] + + Let's remove t1 from Body B. + + >>> B.apply_torque(-t1*B.x) + >>> B.loads + [(B_frame, t2(t)*B_frame.y + t*B_frame.z)] + + To further demonstrate the use, let us consider two bodies such that + a torque `T` is acting on one body, and `-T` on the other. + + >>> from sympy.physics.mechanics import Body, dynamicsymbols + >>> with ignore_warnings(DeprecationWarning): + ... N = Body('N') #Newtonion frame + ... B1 = Body('B1') + ... B2 = Body('B2') + >>> v = dynamicsymbols('v') + >>> T = v*N.y #Torque + + Now let's apply equal and opposite torque to the bodies. + + >>> B1.apply_torque(T, B2) + + We can check the loads (torques) applied to bodies now. + + >>> B1.loads + [(B1_frame, v(t)*N_frame.y)] + >>> B2.loads + [(B2_frame, - v(t)*N_frame.y)] + + Notes + ===== + + If a new torque is applied on body which already has some torque applied on it, + then the new torque is added to the previous torque about the body's frame. + + """ + + if not isinstance(torque, Vector): + raise TypeError("A Vector must be supplied to add torque.") + + if reaction_body is not None: + reaction_body.apply_torque(-torque) + + for load in self._loads: + if self.frame in load: + torque += load[1] + self._loads.remove(load) + break + self._loads.append((self.frame, torque)) + + def clear_loads(self): + """ + Clears the Body's loads list. + + Example + ======= + + As Body has been deprecated, the following examples are for illustrative + purposes only. The functionality of Body is fully captured by + :class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation + warning we can use the ignore_warnings context manager. + + >>> from sympy.utilities.exceptions import ignore_warnings + >>> from sympy.physics.mechanics import Body + >>> with ignore_warnings(DeprecationWarning): + ... B = Body('B') + >>> force = B.x + B.y + >>> B.apply_force(force) + >>> B.loads + [(B_masscenter, B_frame.x + B_frame.y)] + >>> B.clear_loads() + >>> B.loads + [] + + """ + + self._loads = [] + + def remove_load(self, about=None): + """ + Remove load about a point or frame. + + Parameters + ========== + + about : Point or ReferenceFrame, optional + The point about which force is applied, + and is to be removed. + If about is None, then the torque about + self's frame is removed. + + Example + ======= + + As Body has been deprecated, the following examples are for illustrative + purposes only. The functionality of Body is fully captured by + :class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation + warning we can use the ignore_warnings context manager. + + >>> from sympy.utilities.exceptions import ignore_warnings + >>> from sympy.physics.mechanics import Body, Point + >>> with ignore_warnings(DeprecationWarning): + ... B = Body('B') + >>> P = Point('P') + >>> f1 = B.x + >>> f2 = B.y + >>> B.apply_force(f1) + >>> B.apply_force(f2, P) + >>> B.loads + [(B_masscenter, B_frame.x), (P, B_frame.y)] + + >>> B.remove_load(P) + >>> B.loads + [(B_masscenter, B_frame.x)] + + """ + + if about is not None: + if not isinstance(about, Point): + raise TypeError('Load is applied about Point or ReferenceFrame.') + else: + about = self.frame + + for load in self._loads: + if about in load: + self._loads.remove(load) + break + + def masscenter_vel(self, body): + """ + Returns the velocity of the mass center with respect to the provided + rigid body or reference frame. + + Parameters + ========== + + body: Body or ReferenceFrame + The rigid body or reference frame to calculate the velocity in. + + Example + ======= + + As Body has been deprecated, the following examples are for illustrative + purposes only. The functionality of Body is fully captured by + :class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation + warning we can use the ignore_warnings context manager. + + >>> from sympy.utilities.exceptions import ignore_warnings + >>> from sympy.physics.mechanics import Body + >>> with ignore_warnings(DeprecationWarning): + ... A = Body('A') + ... B = Body('B') + >>> A.masscenter.set_vel(B.frame, 5*B.frame.x) + >>> A.masscenter_vel(B) + 5*B_frame.x + >>> A.masscenter_vel(B.frame) + 5*B_frame.x + + """ + + if isinstance(body, ReferenceFrame): + frame=body + elif isinstance(body, Body): + frame = body.frame + return self.masscenter.vel(frame) + + def ang_vel_in(self, body): + """ + Returns this body's angular velocity with respect to the provided + rigid body or reference frame. + + Parameters + ========== + + body: Body or ReferenceFrame + The rigid body or reference frame to calculate the angular velocity in. + + Example + ======= + + As Body has been deprecated, the following examples are for illustrative + purposes only. The functionality of Body is fully captured by + :class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation + warning we can use the ignore_warnings context manager. + + >>> from sympy.utilities.exceptions import ignore_warnings + >>> from sympy.physics.mechanics import Body, ReferenceFrame + >>> with ignore_warnings(DeprecationWarning): + ... A = Body('A') + >>> N = ReferenceFrame('N') + >>> with ignore_warnings(DeprecationWarning): + ... B = Body('B', frame=N) + >>> A.frame.set_ang_vel(N, 5*N.x) + >>> A.ang_vel_in(B) + 5*N.x + >>> A.ang_vel_in(N) + 5*N.x + + """ + + if isinstance(body, ReferenceFrame): + frame=body + elif isinstance(body, Body): + frame = body.frame + return self.frame.ang_vel_in(frame) + + def dcm(self, body): + """ + Returns the direction cosine matrix of this body relative to the + provided rigid body or reference frame. + + Parameters + ========== + + body: Body or ReferenceFrame + The rigid body or reference frame to calculate the dcm. + + Example + ======= + + As Body has been deprecated, the following examples are for illustrative + purposes only. The functionality of Body is fully captured by + :class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation + warning we can use the ignore_warnings context manager. + + >>> from sympy.utilities.exceptions import ignore_warnings + >>> from sympy.physics.mechanics import Body + >>> with ignore_warnings(DeprecationWarning): + ... A = Body('A') + ... B = Body('B') + >>> A.frame.orient_axis(B.frame, B.frame.x, 5) + >>> A.dcm(B) + Matrix([ + [1, 0, 0], + [0, cos(5), sin(5)], + [0, -sin(5), cos(5)]]) + >>> A.dcm(B.frame) + Matrix([ + [1, 0, 0], + [0, cos(5), sin(5)], + [0, -sin(5), cos(5)]]) + + """ + + if isinstance(body, ReferenceFrame): + frame=body + elif isinstance(body, Body): + frame = body.frame + return self.frame.dcm(frame) + + def parallel_axis(self, point, frame=None): + """Returns the inertia dyadic of the body with respect to another + point. + + Parameters + ========== + + point : sympy.physics.vector.Point + The point to express the inertia dyadic about. + frame : sympy.physics.vector.ReferenceFrame + The reference frame used to construct the dyadic. + + Returns + ======= + + inertia : sympy.physics.vector.Dyadic + The inertia dyadic of the rigid body expressed about the provided + point. + + Example + ======= + + As Body has been deprecated, the following examples are for illustrative + purposes only. The functionality of Body is fully captured by + :class:`~.RigidBody` and :class:`~.Particle`. To ignore the deprecation + warning we can use the ignore_warnings context manager. + + >>> from sympy.utilities.exceptions import ignore_warnings + >>> from sympy.physics.mechanics import Body + >>> with ignore_warnings(DeprecationWarning): + ... A = Body('A') + >>> P = A.masscenter.locatenew('point', 3 * A.x + 5 * A.y) + >>> A.parallel_axis(P).to_matrix(A.frame) + Matrix([ + [A_ixx + 25*A_mass, A_ixy - 15*A_mass, A_izx], + [A_ixy - 15*A_mass, A_iyy + 9*A_mass, A_iyz], + [ A_izx, A_iyz, A_izz + 34*A_mass]]) + + """ + if self.is_rigidbody: + return RigidBody.parallel_axis(self, point, frame) + return Particle.parallel_axis(self, point, frame) diff --git a/lib/python3.12/site-packages/sympy/physics/mechanics/body_base.py b/lib/python3.12/site-packages/sympy/physics/mechanics/body_base.py new file mode 100644 index 0000000000000000000000000000000000000000..d2546faf685f579d2aea10ed7f139a4beced7dd0 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/mechanics/body_base.py @@ -0,0 +1,94 @@ +from abc import ABC, abstractmethod +from sympy import Symbol, sympify +from sympy.physics.vector import Point + +__all__ = ['BodyBase'] + + +class BodyBase(ABC): + """Abstract class for body type objects.""" + def __init__(self, name, masscenter=None, mass=None): + # Note: If frame=None, no auto-generated frame is created, because a + # Particle does not need to have a frame by default. + if not isinstance(name, str): + raise TypeError('Supply a valid name.') + self._name = name + if mass is None: + mass = Symbol(f'{name}_mass') + if masscenter is None: + masscenter = Point(f'{name}_masscenter') + self.mass = mass + self.masscenter = masscenter + self.potential_energy = 0 + self.points = [] + + def __str__(self): + return self.name + + def __repr__(self): + return (f'{self.__class__.__name__}({repr(self.name)}, masscenter=' + f'{repr(self.masscenter)}, mass={repr(self.mass)})') + + @property + def name(self): + """The name of the body.""" + return self._name + + @property + def masscenter(self): + """The body's center of mass.""" + return self._masscenter + + @masscenter.setter + def masscenter(self, point): + if not isinstance(point, Point): + raise TypeError("The body's center of mass must be a Point object.") + self._masscenter = point + + @property + def mass(self): + """The body's mass.""" + return self._mass + + @mass.setter + def mass(self, mass): + self._mass = sympify(mass) + + @property + def potential_energy(self): + """The potential energy of the body. + + Examples + ======== + + >>> from sympy.physics.mechanics import Particle, Point + >>> from sympy import symbols + >>> m, g, h = symbols('m g h') + >>> O = Point('O') + >>> P = Particle('P', O, m) + >>> P.potential_energy = m * g * h + >>> P.potential_energy + g*h*m + + """ + return self._potential_energy + + @potential_energy.setter + def potential_energy(self, scalar): + self._potential_energy = sympify(scalar) + + @abstractmethod + def kinetic_energy(self, frame): + pass + + @abstractmethod + def linear_momentum(self, frame): + pass + + @abstractmethod + def angular_momentum(self, point, frame): + pass + + @abstractmethod + def parallel_axis(self, point, frame): + pass diff --git a/lib/python3.12/site-packages/sympy/physics/mechanics/joint.py b/lib/python3.12/site-packages/sympy/physics/mechanics/joint.py new file mode 100644 index 0000000000000000000000000000000000000000..af53cc67e4d70abc7b651da123a9361ddf263b60 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/mechanics/joint.py @@ -0,0 +1,2188 @@ +# coding=utf-8 + +from abc import ABC, abstractmethod + +from sympy import pi, Derivative, Matrix +from sympy.core.function import AppliedUndef +from sympy.physics.mechanics.body_base import BodyBase +from sympy.physics.mechanics.functions import _validate_coordinates +from sympy.physics.vector import (Vector, dynamicsymbols, cross, Point, + ReferenceFrame) +from sympy.utilities.iterables import iterable +from sympy.utilities.exceptions import sympy_deprecation_warning + +__all__ = ['Joint', 'PinJoint', 'PrismaticJoint', 'CylindricalJoint', + 'PlanarJoint', 'SphericalJoint', 'WeldJoint'] + + +class Joint(ABC): + """Abstract base class for all specific joints. + + Explanation + =========== + + A joint subtracts degrees of freedom from a body. This is the base class + for all specific joints and holds all common methods acting as an interface + for all joints. Custom joint can be created by inheriting Joint class and + defining all abstract functions. + + The abstract methods are: + + - ``_generate_coordinates`` + - ``_generate_speeds`` + - ``_orient_frames`` + - ``_set_angular_velocity`` + - ``_set_linear_velocity`` + + Parameters + ========== + + name : string + A unique name for the joint. + parent : Particle or RigidBody or Body + The parent body of joint. + child : Particle or RigidBody or Body + The child body of joint. + coordinates : iterable of dynamicsymbols, optional + Generalized coordinates of the joint. + speeds : iterable of dynamicsymbols, optional + Generalized speeds of joint. + parent_point : Point or Vector, optional + Attachment point where the joint is fixed to the parent body. If a + vector is provided, then the attachment point is computed by adding the + vector to the body's mass center. The default value is the parent's mass + center. + child_point : Point or Vector, optional + Attachment point where the joint is fixed to the child body. If a + vector is provided, then the attachment point is computed by adding the + vector to the body's mass center. The default value is the child's mass + center. + parent_axis : Vector, optional + .. deprecated:: 1.12 + Axis fixed in the parent body which aligns with an axis fixed in the + child body. The default is the x axis of parent's reference frame. + For more information on this deprecation, see + :ref:`deprecated-mechanics-joint-axis`. + child_axis : Vector, optional + .. deprecated:: 1.12 + Axis fixed in the child body which aligns with an axis fixed in the + parent body. The default is the x axis of child's reference frame. + For more information on this deprecation, see + :ref:`deprecated-mechanics-joint-axis`. + parent_interframe : ReferenceFrame, optional + Intermediate frame of the parent body with respect to which the joint + transformation is formulated. If a Vector is provided then an interframe + is created which aligns its X axis with the given vector. The default + value is the parent's own frame. + child_interframe : ReferenceFrame, optional + Intermediate frame of the child body with respect to which the joint + transformation is formulated. If a Vector is provided then an interframe + is created which aligns its X axis with the given vector. The default + value is the child's own frame. + parent_joint_pos : Point or Vector, optional + .. deprecated:: 1.12 + This argument is replaced by parent_point and will be removed in a + future version. + See :ref:`deprecated-mechanics-joint-pos` for more information. + child_joint_pos : Point or Vector, optional + .. deprecated:: 1.12 + This argument is replaced by child_point and will be removed in a + future version. + See :ref:`deprecated-mechanics-joint-pos` for more information. + + Attributes + ========== + + name : string + The joint's name. + parent : Particle or RigidBody or Body + The joint's parent body. + child : Particle or RigidBody or Body + The joint's child body. + coordinates : Matrix + Matrix of the joint's generalized coordinates. + speeds : Matrix + Matrix of the joint's generalized speeds. + parent_point : Point + Attachment point where the joint is fixed to the parent body. + child_point : Point + Attachment point where the joint is fixed to the child body. + parent_axis : Vector + The axis fixed in the parent frame that represents the joint. + child_axis : Vector + The axis fixed in the child frame that represents the joint. + parent_interframe : ReferenceFrame + Intermediate frame of the parent body with respect to which the joint + transformation is formulated. + child_interframe : ReferenceFrame + Intermediate frame of the child body with respect to which the joint + transformation is formulated. + kdes : Matrix + Kinematical differential equations of the joint. + + Notes + ===== + + When providing a vector as the intermediate frame, a new intermediate frame + is created which aligns its X axis with the provided vector. This is done + with a single fixed rotation about a rotation axis. This rotation axis is + determined by taking the cross product of the ``body.x`` axis with the + provided vector. In the case where the provided vector is in the ``-body.x`` + direction, the rotation is done about the ``body.y`` axis. + + """ + + def __init__(self, name, parent, child, coordinates=None, speeds=None, + parent_point=None, child_point=None, parent_interframe=None, + child_interframe=None, parent_axis=None, child_axis=None, + parent_joint_pos=None, child_joint_pos=None): + + if not isinstance(name, str): + raise TypeError('Supply a valid name.') + self._name = name + + if not isinstance(parent, BodyBase): + raise TypeError('Parent must be a body.') + self._parent = parent + + if not isinstance(child, BodyBase): + raise TypeError('Child must be a body.') + self._child = child + + if parent_axis is not None or child_axis is not None: + sympy_deprecation_warning( + """ + The parent_axis and child_axis arguments for the Joint classes + are deprecated. Instead use parent_interframe, child_interframe. + """, + deprecated_since_version="1.12", + active_deprecations_target="deprecated-mechanics-joint-axis", + stacklevel=4 + ) + if parent_interframe is None: + parent_interframe = parent_axis + if child_interframe is None: + child_interframe = child_axis + + # Set parent and child frame attributes + if hasattr(self._parent, 'frame'): + self._parent_frame = self._parent.frame + else: + if isinstance(parent_interframe, ReferenceFrame): + self._parent_frame = parent_interframe + else: + self._parent_frame = ReferenceFrame( + f'{self.name}_{self._parent.name}_frame') + if hasattr(self._child, 'frame'): + self._child_frame = self._child.frame + else: + if isinstance(child_interframe, ReferenceFrame): + self._child_frame = child_interframe + else: + self._child_frame = ReferenceFrame( + f'{self.name}_{self._child.name}_frame') + + self._parent_interframe = self._locate_joint_frame( + self._parent, parent_interframe, self._parent_frame) + self._child_interframe = self._locate_joint_frame( + self._child, child_interframe, self._child_frame) + self._parent_axis = self._axis(parent_axis, self._parent_frame) + self._child_axis = self._axis(child_axis, self._child_frame) + + if parent_joint_pos is not None or child_joint_pos is not None: + sympy_deprecation_warning( + """ + The parent_joint_pos and child_joint_pos arguments for the Joint + classes are deprecated. Instead use parent_point and child_point. + """, + deprecated_since_version="1.12", + active_deprecations_target="deprecated-mechanics-joint-pos", + stacklevel=4 + ) + if parent_point is None: + parent_point = parent_joint_pos + if child_point is None: + child_point = child_joint_pos + self._parent_point = self._locate_joint_pos( + self._parent, parent_point, self._parent_frame) + self._child_point = self._locate_joint_pos( + self._child, child_point, self._child_frame) + + self._coordinates = self._generate_coordinates(coordinates) + self._speeds = self._generate_speeds(speeds) + _validate_coordinates(self.coordinates, self.speeds) + self._kdes = self._generate_kdes() + + self._orient_frames() + self._set_angular_velocity() + self._set_linear_velocity() + + def __str__(self): + return self.name + + def __repr__(self): + return self.__str__() + + @property + def name(self): + """Name of the joint.""" + return self._name + + @property + def parent(self): + """Parent body of Joint.""" + return self._parent + + @property + def child(self): + """Child body of Joint.""" + return self._child + + @property + def coordinates(self): + """Matrix of the joint's generalized coordinates.""" + return self._coordinates + + @property + def speeds(self): + """Matrix of the joint's generalized speeds.""" + return self._speeds + + @property + def kdes(self): + """Kinematical differential equations of the joint.""" + return self._kdes + + @property + def parent_axis(self): + """The axis of parent frame.""" + # Will be removed with `deprecated-mechanics-joint-axis` + return self._parent_axis + + @property + def child_axis(self): + """The axis of child frame.""" + # Will be removed with `deprecated-mechanics-joint-axis` + return self._child_axis + + @property + def parent_point(self): + """Attachment point where the joint is fixed to the parent body.""" + return self._parent_point + + @property + def child_point(self): + """Attachment point where the joint is fixed to the child body.""" + return self._child_point + + @property + def parent_interframe(self): + return self._parent_interframe + + @property + def child_interframe(self): + return self._child_interframe + + @abstractmethod + def _generate_coordinates(self, coordinates): + """Generate Matrix of the joint's generalized coordinates.""" + pass + + @abstractmethod + def _generate_speeds(self, speeds): + """Generate Matrix of the joint's generalized speeds.""" + pass + + @abstractmethod + def _orient_frames(self): + """Orient frames as per the joint.""" + pass + + @abstractmethod + def _set_angular_velocity(self): + """Set angular velocity of the joint related frames.""" + pass + + @abstractmethod + def _set_linear_velocity(self): + """Set velocity of related points to the joint.""" + pass + + @staticmethod + def _to_vector(matrix, frame): + """Converts a matrix to a vector in the given frame.""" + return Vector([(matrix, frame)]) + + @staticmethod + def _axis(ax, *frames): + """Check whether an axis is fixed in one of the frames.""" + if ax is None: + ax = frames[0].x + return ax + if not isinstance(ax, Vector): + raise TypeError("Axis must be a Vector.") + ref_frame = None # Find a body in which the axis can be expressed + for frame in frames: + try: + ax.to_matrix(frame) + except ValueError: + pass + else: + ref_frame = frame + break + if ref_frame is None: + raise ValueError("Axis cannot be expressed in one of the body's " + "frames.") + if not ax.dt(ref_frame) == 0: + raise ValueError('Axis cannot be time-varying when viewed from the ' + 'associated body.') + return ax + + @staticmethod + def _choose_rotation_axis(frame, axis): + components = axis.to_matrix(frame) + x, y, z = components[0], components[1], components[2] + + if x != 0: + if y != 0: + if z != 0: + return cross(axis, frame.x) + if z != 0: + return frame.y + return frame.z + else: + if y != 0: + return frame.x + return frame.y + + @staticmethod + def _create_aligned_interframe(frame, align_axis, frame_axis=None, + frame_name=None): + """ + Returns an intermediate frame, where the ``frame_axis`` defined in + ``frame`` is aligned with ``axis``. By default this means that the X + axis will be aligned with ``axis``. + + Parameters + ========== + + frame : BodyBase or ReferenceFrame + The body or reference frame with respect to which the intermediate + frame is oriented. + align_axis : Vector + The vector with respect to which the intermediate frame will be + aligned. + frame_axis : Vector + The vector of the frame which should get aligned with ``axis``. The + default is the X axis of the frame. + frame_name : string + Name of the to be created intermediate frame. The default adds + "_int_frame" to the name of ``frame``. + + Example + ======= + + An intermediate frame, where the X axis of the parent becomes aligned + with ``parent.y + parent.z`` can be created as follows: + + >>> from sympy.physics.mechanics.joint import Joint + >>> from sympy.physics.mechanics import RigidBody + >>> parent = RigidBody('parent') + >>> parent_interframe = Joint._create_aligned_interframe( + ... parent, parent.y + parent.z) + >>> parent_interframe + parent_int_frame + >>> parent.frame.dcm(parent_interframe) + Matrix([ + [ 0, -sqrt(2)/2, -sqrt(2)/2], + [sqrt(2)/2, 1/2, -1/2], + [sqrt(2)/2, -1/2, 1/2]]) + >>> (parent.y + parent.z).express(parent_interframe) + sqrt(2)*parent_int_frame.x + + Notes + ===== + + The direction cosine matrix between the given frame and intermediate + frame is formed using a simple rotation about an axis that is normal to + both ``align_axis`` and ``frame_axis``. In general, the normal axis is + formed by crossing the ``frame_axis`` with the ``align_axis``. The + exception is if the axes are parallel with opposite directions, in which + case the rotation vector is chosen using the rules in the following + table with the vectors expressed in the given frame: + + .. list-table:: + :header-rows: 1 + + * - ``align_axis`` + - ``frame_axis`` + - ``rotation_axis`` + * - ``-x`` + - ``x`` + - ``z`` + * - ``-y`` + - ``y`` + - ``x`` + * - ``-z`` + - ``z`` + - ``y`` + * - ``-x-y`` + - ``x+y`` + - ``z`` + * - ``-y-z`` + - ``y+z`` + - ``x`` + * - ``-x-z`` + - ``x+z`` + - ``y`` + * - ``-x-y-z`` + - ``x+y+z`` + - ``(x+y+z) × x`` + + """ + if isinstance(frame, BodyBase): + frame = frame.frame + if frame_axis is None: + frame_axis = frame.x + if frame_name is None: + if frame.name[-6:] == '_frame': + frame_name = f'{frame.name[:-6]}_int_frame' + else: + frame_name = f'{frame.name}_int_frame' + angle = frame_axis.angle_between(align_axis) + rotation_axis = cross(frame_axis, align_axis) + if rotation_axis == Vector(0) and angle == 0: + return frame + if angle == pi: + rotation_axis = Joint._choose_rotation_axis(frame, align_axis) + + int_frame = ReferenceFrame(frame_name) + int_frame.orient_axis(frame, rotation_axis, angle) + int_frame.set_ang_vel(frame, 0 * rotation_axis) + return int_frame + + def _generate_kdes(self): + """Generate kinematical differential equations.""" + kdes = [] + t = dynamicsymbols._t + for i in range(len(self.coordinates)): + kdes.append(-self.coordinates[i].diff(t) + self.speeds[i]) + return Matrix(kdes) + + def _locate_joint_pos(self, body, joint_pos, body_frame=None): + """Returns the attachment point of a body.""" + if body_frame is None: + body_frame = body.frame + if joint_pos is None: + return body.masscenter + if not isinstance(joint_pos, (Point, Vector)): + raise TypeError('Attachment point must be a Point or Vector.') + if isinstance(joint_pos, Vector): + point_name = f'{self.name}_{body.name}_joint' + joint_pos = body.masscenter.locatenew(point_name, joint_pos) + if not joint_pos.pos_from(body.masscenter).dt(body_frame) == 0: + raise ValueError('Attachment point must be fixed to the associated ' + 'body.') + return joint_pos + + def _locate_joint_frame(self, body, interframe, body_frame=None): + """Returns the attachment frame of a body.""" + if body_frame is None: + body_frame = body.frame + if interframe is None: + return body_frame + if isinstance(interframe, Vector): + interframe = Joint._create_aligned_interframe( + body_frame, interframe, + frame_name=f'{self.name}_{body.name}_int_frame') + elif not isinstance(interframe, ReferenceFrame): + raise TypeError('Interframe must be a ReferenceFrame.') + if not interframe.ang_vel_in(body_frame) == 0: + raise ValueError(f'Interframe {interframe} is not fixed to body ' + f'{body}.') + body.masscenter.set_vel(interframe, 0) # Fixate interframe to body + return interframe + + def _fill_coordinate_list(self, coordinates, n_coords, label='q', offset=0, + number_single=False): + """Helper method for _generate_coordinates and _generate_speeds. + + Parameters + ========== + + coordinates : iterable + Iterable of coordinates or speeds that have been provided. + n_coords : Integer + Number of coordinates that should be returned. + label : String, optional + Coordinate type either 'q' (coordinates) or 'u' (speeds). The + Default is 'q'. + offset : Integer + Count offset when creating new dynamicsymbols. The default is 0. + number_single : Boolean + Boolean whether if n_coords == 1, number should still be used. The + default is False. + + """ + + def create_symbol(number): + if n_coords == 1 and not number_single: + return dynamicsymbols(f'{label}_{self.name}') + return dynamicsymbols(f'{label}{number}_{self.name}') + + name = 'generalized coordinate' if label == 'q' else 'generalized speed' + generated_coordinates = [] + if coordinates is None: + coordinates = [] + elif not iterable(coordinates): + coordinates = [coordinates] + if not (len(coordinates) == 0 or len(coordinates) == n_coords): + raise ValueError(f'Expected {n_coords} {name}s, instead got ' + f'{len(coordinates)} {name}s.') + # Supports more iterables, also Matrix + for i, coord in enumerate(coordinates): + if coord is None: + generated_coordinates.append(create_symbol(i + offset)) + elif isinstance(coord, (AppliedUndef, Derivative)): + generated_coordinates.append(coord) + else: + raise TypeError(f'The {name} {coord} should have been a ' + f'dynamicsymbol.') + for i in range(len(coordinates) + offset, n_coords + offset): + generated_coordinates.append(create_symbol(i)) + return Matrix(generated_coordinates) + + +class PinJoint(Joint): + """Pin (Revolute) Joint. + + .. raw:: html + :file: ../../../doc/src/modules/physics/mechanics/api/PinJoint.svg + + Explanation + =========== + + A pin joint is defined such that the joint rotation axis is fixed in both + the child and parent and the location of the joint is relative to the mass + center of each body. The child rotates an angle, θ, from the parent about + the rotation axis and has a simple angular speed, ω, relative to the + parent. The direction cosine matrix between the child interframe and + parent interframe is formed using a simple rotation about the joint axis. + The page on the joints framework gives a more detailed explanation of the + intermediate frames. + + Parameters + ========== + + name : string + A unique name for the joint. + parent : Particle or RigidBody or Body + The parent body of joint. + child : Particle or RigidBody or Body + The child body of joint. + coordinates : dynamicsymbol, optional + Generalized coordinates of the joint. + speeds : dynamicsymbol, optional + Generalized speeds of joint. + parent_point : Point or Vector, optional + Attachment point where the joint is fixed to the parent body. If a + vector is provided, then the attachment point is computed by adding the + vector to the body's mass center. The default value is the parent's mass + center. + child_point : Point or Vector, optional + Attachment point where the joint is fixed to the child body. If a + vector is provided, then the attachment point is computed by adding the + vector to the body's mass center. The default value is the child's mass + center. + parent_axis : Vector, optional + .. deprecated:: 1.12 + Axis fixed in the parent body which aligns with an axis fixed in the + child body. The default is the x axis of parent's reference frame. + For more information on this deprecation, see + :ref:`deprecated-mechanics-joint-axis`. + child_axis : Vector, optional + .. deprecated:: 1.12 + Axis fixed in the child body which aligns with an axis fixed in the + parent body. The default is the x axis of child's reference frame. + For more information on this deprecation, see + :ref:`deprecated-mechanics-joint-axis`. + parent_interframe : ReferenceFrame, optional + Intermediate frame of the parent body with respect to which the joint + transformation is formulated. If a Vector is provided then an interframe + is created which aligns its X axis with the given vector. The default + value is the parent's own frame. + child_interframe : ReferenceFrame, optional + Intermediate frame of the child body with respect to which the joint + transformation is formulated. If a Vector is provided then an interframe + is created which aligns its X axis with the given vector. The default + value is the child's own frame. + joint_axis : Vector + The axis about which the rotation occurs. Note that the components + of this axis are the same in the parent_interframe and child_interframe. + parent_joint_pos : Point or Vector, optional + .. deprecated:: 1.12 + This argument is replaced by parent_point and will be removed in a + future version. + See :ref:`deprecated-mechanics-joint-pos` for more information. + child_joint_pos : Point or Vector, optional + .. deprecated:: 1.12 + This argument is replaced by child_point and will be removed in a + future version. + See :ref:`deprecated-mechanics-joint-pos` for more information. + + Attributes + ========== + + name : string + The joint's name. + parent : Particle or RigidBody or Body + The joint's parent body. + child : Particle or RigidBody or Body + The joint's child body. + coordinates : Matrix + Matrix of the joint's generalized coordinates. The default value is + ``dynamicsymbols(f'q_{joint.name}')``. + speeds : Matrix + Matrix of the joint's generalized speeds. The default value is + ``dynamicsymbols(f'u_{joint.name}')``. + parent_point : Point + Attachment point where the joint is fixed to the parent body. + child_point : Point + Attachment point where the joint is fixed to the child body. + parent_axis : Vector + The axis fixed in the parent frame that represents the joint. + child_axis : Vector + The axis fixed in the child frame that represents the joint. + parent_interframe : ReferenceFrame + Intermediate frame of the parent body with respect to which the joint + transformation is formulated. + child_interframe : ReferenceFrame + Intermediate frame of the child body with respect to which the joint + transformation is formulated. + joint_axis : Vector + The axis about which the rotation occurs. Note that the components of + this axis are the same in the parent_interframe and child_interframe. + kdes : Matrix + Kinematical differential equations of the joint. + + Examples + ========= + + A single pin joint is created from two bodies and has the following basic + attributes: + + >>> from sympy.physics.mechanics import RigidBody, PinJoint + >>> parent = RigidBody('P') + >>> parent + P + >>> child = RigidBody('C') + >>> child + C + >>> joint = PinJoint('PC', parent, child) + >>> joint + PinJoint: PC parent: P child: C + >>> joint.name + 'PC' + >>> joint.parent + P + >>> joint.child + C + >>> joint.parent_point + P_masscenter + >>> joint.child_point + C_masscenter + >>> joint.parent_axis + P_frame.x + >>> joint.child_axis + C_frame.x + >>> joint.coordinates + Matrix([[q_PC(t)]]) + >>> joint.speeds + Matrix([[u_PC(t)]]) + >>> child.frame.ang_vel_in(parent.frame) + u_PC(t)*P_frame.x + >>> child.frame.dcm(parent.frame) + Matrix([ + [1, 0, 0], + [0, cos(q_PC(t)), sin(q_PC(t))], + [0, -sin(q_PC(t)), cos(q_PC(t))]]) + >>> joint.child_point.pos_from(joint.parent_point) + 0 + + To further demonstrate the use of the pin joint, the kinematics of simple + double pendulum that rotates about the Z axis of each connected body can be + created as follows. + + >>> from sympy import symbols, trigsimp + >>> from sympy.physics.mechanics import RigidBody, PinJoint + >>> l1, l2 = symbols('l1 l2') + + First create bodies to represent the fixed ceiling and one to represent + each pendulum bob. + + >>> ceiling = RigidBody('C') + >>> upper_bob = RigidBody('U') + >>> lower_bob = RigidBody('L') + + The first joint will connect the upper bob to the ceiling by a distance of + ``l1`` and the joint axis will be about the Z axis for each body. + + >>> ceiling_joint = PinJoint('P1', ceiling, upper_bob, + ... child_point=-l1*upper_bob.frame.x, + ... joint_axis=ceiling.frame.z) + + The second joint will connect the lower bob to the upper bob by a distance + of ``l2`` and the joint axis will also be about the Z axis for each body. + + >>> pendulum_joint = PinJoint('P2', upper_bob, lower_bob, + ... child_point=-l2*lower_bob.frame.x, + ... joint_axis=upper_bob.frame.z) + + Once the joints are established the kinematics of the connected bodies can + be accessed. First the direction cosine matrices of pendulum link relative + to the ceiling are found: + + >>> upper_bob.frame.dcm(ceiling.frame) + Matrix([ + [ cos(q_P1(t)), sin(q_P1(t)), 0], + [-sin(q_P1(t)), cos(q_P1(t)), 0], + [ 0, 0, 1]]) + >>> trigsimp(lower_bob.frame.dcm(ceiling.frame)) + Matrix([ + [ cos(q_P1(t) + q_P2(t)), sin(q_P1(t) + q_P2(t)), 0], + [-sin(q_P1(t) + q_P2(t)), cos(q_P1(t) + q_P2(t)), 0], + [ 0, 0, 1]]) + + The position of the lower bob's masscenter is found with: + + >>> lower_bob.masscenter.pos_from(ceiling.masscenter) + l1*U_frame.x + l2*L_frame.x + + The angular velocities of the two pendulum links can be computed with + respect to the ceiling. + + >>> upper_bob.frame.ang_vel_in(ceiling.frame) + u_P1(t)*C_frame.z + >>> lower_bob.frame.ang_vel_in(ceiling.frame) + u_P1(t)*C_frame.z + u_P2(t)*U_frame.z + + And finally, the linear velocities of the two pendulum bobs can be computed + with respect to the ceiling. + + >>> upper_bob.masscenter.vel(ceiling.frame) + l1*u_P1(t)*U_frame.y + >>> lower_bob.masscenter.vel(ceiling.frame) + l1*u_P1(t)*U_frame.y + l2*(u_P1(t) + u_P2(t))*L_frame.y + + """ + + def __init__(self, name, parent, child, coordinates=None, speeds=None, + parent_point=None, child_point=None, parent_interframe=None, + child_interframe=None, parent_axis=None, child_axis=None, + joint_axis=None, parent_joint_pos=None, child_joint_pos=None): + + self._joint_axis = joint_axis + super().__init__(name, parent, child, coordinates, speeds, parent_point, + child_point, parent_interframe, child_interframe, + parent_axis, child_axis, parent_joint_pos, + child_joint_pos) + + def __str__(self): + return (f'PinJoint: {self.name} parent: {self.parent} ' + f'child: {self.child}') + + @property + def joint_axis(self): + """Axis about which the child rotates with respect to the parent.""" + return self._joint_axis + + def _generate_coordinates(self, coordinate): + return self._fill_coordinate_list(coordinate, 1, 'q') + + def _generate_speeds(self, speed): + return self._fill_coordinate_list(speed, 1, 'u') + + def _orient_frames(self): + self._joint_axis = self._axis(self.joint_axis, self.parent_interframe) + self.child_interframe.orient_axis( + self.parent_interframe, self.joint_axis, self.coordinates[0]) + + def _set_angular_velocity(self): + self.child_interframe.set_ang_vel(self.parent_interframe, self.speeds[ + 0] * self.joint_axis.normalize()) + + def _set_linear_velocity(self): + self.child_point.set_pos(self.parent_point, 0) + self.parent_point.set_vel(self._parent_frame, 0) + self.child_point.set_vel(self._child_frame, 0) + self.child.masscenter.v2pt_theory(self.parent_point, + self._parent_frame, self._child_frame) + + +class PrismaticJoint(Joint): + """Prismatic (Sliding) Joint. + + .. image:: PrismaticJoint.svg + + Explanation + =========== + + It is defined such that the child body translates with respect to the parent + body along the body-fixed joint axis. The location of the joint is defined + by two points, one in each body, which coincide when the generalized + coordinate is zero. The direction cosine matrix between the + parent_interframe and child_interframe is the identity matrix. Therefore, + the direction cosine matrix between the parent and child frames is fully + defined by the definition of the intermediate frames. The page on the joints + framework gives a more detailed explanation of the intermediate frames. + + Parameters + ========== + + name : string + A unique name for the joint. + parent : Particle or RigidBody or Body + The parent body of joint. + child : Particle or RigidBody or Body + The child body of joint. + coordinates : dynamicsymbol, optional + Generalized coordinates of the joint. The default value is + ``dynamicsymbols(f'q_{joint.name}')``. + speeds : dynamicsymbol, optional + Generalized speeds of joint. The default value is + ``dynamicsymbols(f'u_{joint.name}')``. + parent_point : Point or Vector, optional + Attachment point where the joint is fixed to the parent body. If a + vector is provided, then the attachment point is computed by adding the + vector to the body's mass center. The default value is the parent's mass + center. + child_point : Point or Vector, optional + Attachment point where the joint is fixed to the child body. If a + vector is provided, then the attachment point is computed by adding the + vector to the body's mass center. The default value is the child's mass + center. + parent_axis : Vector, optional + .. deprecated:: 1.12 + Axis fixed in the parent body which aligns with an axis fixed in the + child body. The default is the x axis of parent's reference frame. + For more information on this deprecation, see + :ref:`deprecated-mechanics-joint-axis`. + child_axis : Vector, optional + .. deprecated:: 1.12 + Axis fixed in the child body which aligns with an axis fixed in the + parent body. The default is the x axis of child's reference frame. + For more information on this deprecation, see + :ref:`deprecated-mechanics-joint-axis`. + parent_interframe : ReferenceFrame, optional + Intermediate frame of the parent body with respect to which the joint + transformation is formulated. If a Vector is provided then an interframe + is created which aligns its X axis with the given vector. The default + value is the parent's own frame. + child_interframe : ReferenceFrame, optional + Intermediate frame of the child body with respect to which the joint + transformation is formulated. If a Vector is provided then an interframe + is created which aligns its X axis with the given vector. The default + value is the child's own frame. + joint_axis : Vector + The axis along which the translation occurs. Note that the components + of this axis are the same in the parent_interframe and child_interframe. + parent_joint_pos : Point or Vector, optional + .. deprecated:: 1.12 + This argument is replaced by parent_point and will be removed in a + future version. + See :ref:`deprecated-mechanics-joint-pos` for more information. + child_joint_pos : Point or Vector, optional + .. deprecated:: 1.12 + This argument is replaced by child_point and will be removed in a + future version. + See :ref:`deprecated-mechanics-joint-pos` for more information. + + Attributes + ========== + + name : string + The joint's name. + parent : Particle or RigidBody or Body + The joint's parent body. + child : Particle or RigidBody or Body + The joint's child body. + coordinates : Matrix + Matrix of the joint's generalized coordinates. + speeds : Matrix + Matrix of the joint's generalized speeds. + parent_point : Point + Attachment point where the joint is fixed to the parent body. + child_point : Point + Attachment point where the joint is fixed to the child body. + parent_axis : Vector + The axis fixed in the parent frame that represents the joint. + child_axis : Vector + The axis fixed in the child frame that represents the joint. + parent_interframe : ReferenceFrame + Intermediate frame of the parent body with respect to which the joint + transformation is formulated. + child_interframe : ReferenceFrame + Intermediate frame of the child body with respect to which the joint + transformation is formulated. + kdes : Matrix + Kinematical differential equations of the joint. + + Examples + ========= + + A single prismatic joint is created from two bodies and has the following + basic attributes: + + >>> from sympy.physics.mechanics import RigidBody, PrismaticJoint + >>> parent = RigidBody('P') + >>> parent + P + >>> child = RigidBody('C') + >>> child + C + >>> joint = PrismaticJoint('PC', parent, child) + >>> joint + PrismaticJoint: PC parent: P child: C + >>> joint.name + 'PC' + >>> joint.parent + P + >>> joint.child + C + >>> joint.parent_point + P_masscenter + >>> joint.child_point + C_masscenter + >>> joint.parent_axis + P_frame.x + >>> joint.child_axis + C_frame.x + >>> joint.coordinates + Matrix([[q_PC(t)]]) + >>> joint.speeds + Matrix([[u_PC(t)]]) + >>> child.frame.ang_vel_in(parent.frame) + 0 + >>> child.frame.dcm(parent.frame) + Matrix([ + [1, 0, 0], + [0, 1, 0], + [0, 0, 1]]) + >>> joint.child_point.pos_from(joint.parent_point) + q_PC(t)*P_frame.x + + To further demonstrate the use of the prismatic joint, the kinematics of two + masses sliding, one moving relative to a fixed body and the other relative + to the moving body. about the X axis of each connected body can be created + as follows. + + >>> from sympy.physics.mechanics import PrismaticJoint, RigidBody + + First create bodies to represent the fixed ceiling and one to represent + a particle. + + >>> wall = RigidBody('W') + >>> Part1 = RigidBody('P1') + >>> Part2 = RigidBody('P2') + + The first joint will connect the particle to the ceiling and the + joint axis will be about the X axis for each body. + + >>> J1 = PrismaticJoint('J1', wall, Part1) + + The second joint will connect the second particle to the first particle + and the joint axis will also be about the X axis for each body. + + >>> J2 = PrismaticJoint('J2', Part1, Part2) + + Once the joint is established the kinematics of the connected bodies can + be accessed. First the direction cosine matrices of Part relative + to the ceiling are found: + + >>> Part1.frame.dcm(wall.frame) + Matrix([ + [1, 0, 0], + [0, 1, 0], + [0, 0, 1]]) + + >>> Part2.frame.dcm(wall.frame) + Matrix([ + [1, 0, 0], + [0, 1, 0], + [0, 0, 1]]) + + The position of the particles' masscenter is found with: + + >>> Part1.masscenter.pos_from(wall.masscenter) + q_J1(t)*W_frame.x + + >>> Part2.masscenter.pos_from(wall.masscenter) + q_J1(t)*W_frame.x + q_J2(t)*P1_frame.x + + The angular velocities of the two particle links can be computed with + respect to the ceiling. + + >>> Part1.frame.ang_vel_in(wall.frame) + 0 + + >>> Part2.frame.ang_vel_in(wall.frame) + 0 + + And finally, the linear velocities of the two particles can be computed + with respect to the ceiling. + + >>> Part1.masscenter.vel(wall.frame) + u_J1(t)*W_frame.x + + >>> Part2.masscenter.vel(wall.frame) + u_J1(t)*W_frame.x + Derivative(q_J2(t), t)*P1_frame.x + + """ + + def __init__(self, name, parent, child, coordinates=None, speeds=None, + parent_point=None, child_point=None, parent_interframe=None, + child_interframe=None, parent_axis=None, child_axis=None, + joint_axis=None, parent_joint_pos=None, child_joint_pos=None): + + self._joint_axis = joint_axis + super().__init__(name, parent, child, coordinates, speeds, parent_point, + child_point, parent_interframe, child_interframe, + parent_axis, child_axis, parent_joint_pos, + child_joint_pos) + + def __str__(self): + return (f'PrismaticJoint: {self.name} parent: {self.parent} ' + f'child: {self.child}') + + @property + def joint_axis(self): + """Axis along which the child translates with respect to the parent.""" + return self._joint_axis + + def _generate_coordinates(self, coordinate): + return self._fill_coordinate_list(coordinate, 1, 'q') + + def _generate_speeds(self, speed): + return self._fill_coordinate_list(speed, 1, 'u') + + def _orient_frames(self): + self._joint_axis = self._axis(self.joint_axis, self.parent_interframe) + self.child_interframe.orient_axis( + self.parent_interframe, self.joint_axis, 0) + + def _set_angular_velocity(self): + self.child_interframe.set_ang_vel(self.parent_interframe, 0) + + def _set_linear_velocity(self): + axis = self.joint_axis.normalize() + self.child_point.set_pos(self.parent_point, self.coordinates[0] * axis) + self.parent_point.set_vel(self._parent_frame, 0) + self.child_point.set_vel(self._child_frame, 0) + self.child_point.set_vel(self._parent_frame, self.speeds[0] * axis) + self.child.masscenter.set_vel(self._parent_frame, self.speeds[0] * axis) + + +class CylindricalJoint(Joint): + """Cylindrical Joint. + + .. image:: CylindricalJoint.svg + :align: center + :width: 600 + + Explanation + =========== + + A cylindrical joint is defined such that the child body both rotates about + and translates along the body-fixed joint axis with respect to the parent + body. The joint axis is both the rotation axis and translation axis. The + location of the joint is defined by two points, one in each body, which + coincide when the generalized coordinate corresponding to the translation is + zero. The direction cosine matrix between the child interframe and parent + interframe is formed using a simple rotation about the joint axis. The page + on the joints framework gives a more detailed explanation of the + intermediate frames. + + Parameters + ========== + + name : string + A unique name for the joint. + parent : Particle or RigidBody or Body + The parent body of joint. + child : Particle or RigidBody or Body + The child body of joint. + rotation_coordinate : dynamicsymbol, optional + Generalized coordinate corresponding to the rotation angle. The default + value is ``dynamicsymbols(f'q0_{joint.name}')``. + translation_coordinate : dynamicsymbol, optional + Generalized coordinate corresponding to the translation distance. The + default value is ``dynamicsymbols(f'q1_{joint.name}')``. + rotation_speed : dynamicsymbol, optional + Generalized speed corresponding to the angular velocity. The default + value is ``dynamicsymbols(f'u0_{joint.name}')``. + translation_speed : dynamicsymbol, optional + Generalized speed corresponding to the translation velocity. The default + value is ``dynamicsymbols(f'u1_{joint.name}')``. + parent_point : Point or Vector, optional + Attachment point where the joint is fixed to the parent body. If a + vector is provided, then the attachment point is computed by adding the + vector to the body's mass center. The default value is the parent's mass + center. + child_point : Point or Vector, optional + Attachment point where the joint is fixed to the child body. If a + vector is provided, then the attachment point is computed by adding the + vector to the body's mass center. The default value is the child's mass + center. + parent_interframe : ReferenceFrame, optional + Intermediate frame of the parent body with respect to which the joint + transformation is formulated. If a Vector is provided then an interframe + is created which aligns its X axis with the given vector. The default + value is the parent's own frame. + child_interframe : ReferenceFrame, optional + Intermediate frame of the child body with respect to which the joint + transformation is formulated. If a Vector is provided then an interframe + is created which aligns its X axis with the given vector. The default + value is the child's own frame. + joint_axis : Vector, optional + The rotation as well as translation axis. Note that the components of + this axis are the same in the parent_interframe and child_interframe. + + Attributes + ========== + + name : string + The joint's name. + parent : Particle or RigidBody or Body + The joint's parent body. + child : Particle or RigidBody or Body + The joint's child body. + rotation_coordinate : dynamicsymbol + Generalized coordinate corresponding to the rotation angle. + translation_coordinate : dynamicsymbol + Generalized coordinate corresponding to the translation distance. + rotation_speed : dynamicsymbol + Generalized speed corresponding to the angular velocity. + translation_speed : dynamicsymbol + Generalized speed corresponding to the translation velocity. + coordinates : Matrix + Matrix of the joint's generalized coordinates. + speeds : Matrix + Matrix of the joint's generalized speeds. + parent_point : Point + Attachment point where the joint is fixed to the parent body. + child_point : Point + Attachment point where the joint is fixed to the child body. + parent_interframe : ReferenceFrame + Intermediate frame of the parent body with respect to which the joint + transformation is formulated. + child_interframe : ReferenceFrame + Intermediate frame of the child body with respect to which the joint + transformation is formulated. + kdes : Matrix + Kinematical differential equations of the joint. + joint_axis : Vector + The axis of rotation and translation. + + Examples + ========= + + A single cylindrical joint is created between two bodies and has the + following basic attributes: + + >>> from sympy.physics.mechanics import RigidBody, CylindricalJoint + >>> parent = RigidBody('P') + >>> parent + P + >>> child = RigidBody('C') + >>> child + C + >>> joint = CylindricalJoint('PC', parent, child) + >>> joint + CylindricalJoint: PC parent: P child: C + >>> joint.name + 'PC' + >>> joint.parent + P + >>> joint.child + C + >>> joint.parent_point + P_masscenter + >>> joint.child_point + C_masscenter + >>> joint.parent_axis + P_frame.x + >>> joint.child_axis + C_frame.x + >>> joint.coordinates + Matrix([ + [q0_PC(t)], + [q1_PC(t)]]) + >>> joint.speeds + Matrix([ + [u0_PC(t)], + [u1_PC(t)]]) + >>> child.frame.ang_vel_in(parent.frame) + u0_PC(t)*P_frame.x + >>> child.frame.dcm(parent.frame) + Matrix([ + [1, 0, 0], + [0, cos(q0_PC(t)), sin(q0_PC(t))], + [0, -sin(q0_PC(t)), cos(q0_PC(t))]]) + >>> joint.child_point.pos_from(joint.parent_point) + q1_PC(t)*P_frame.x + >>> child.masscenter.vel(parent.frame) + u1_PC(t)*P_frame.x + + To further demonstrate the use of the cylindrical joint, the kinematics of + two cylindrical joints perpendicular to each other can be created as follows. + + >>> from sympy import symbols + >>> from sympy.physics.mechanics import RigidBody, CylindricalJoint + >>> r, l, w = symbols('r l w') + + First create bodies to represent the fixed floor with a fixed pole on it. + The second body represents a freely moving tube around that pole. The third + body represents a solid flag freely translating along and rotating around + the Y axis of the tube. + + >>> floor = RigidBody('floor') + >>> tube = RigidBody('tube') + >>> flag = RigidBody('flag') + + The first joint will connect the first tube to the floor with it translating + along and rotating around the Z axis of both bodies. + + >>> floor_joint = CylindricalJoint('C1', floor, tube, joint_axis=floor.z) + + The second joint will connect the tube perpendicular to the flag along the Y + axis of both the tube and the flag, with the joint located at a distance + ``r`` from the tube's center of mass and a combination of the distances + ``l`` and ``w`` from the flag's center of mass. + + >>> flag_joint = CylindricalJoint('C2', tube, flag, + ... parent_point=r * tube.y, + ... child_point=-w * flag.y + l * flag.z, + ... joint_axis=tube.y) + + Once the joints are established the kinematics of the connected bodies can + be accessed. First the direction cosine matrices of both the body and the + flag relative to the floor are found: + + >>> tube.frame.dcm(floor.frame) + Matrix([ + [ cos(q0_C1(t)), sin(q0_C1(t)), 0], + [-sin(q0_C1(t)), cos(q0_C1(t)), 0], + [ 0, 0, 1]]) + >>> flag.frame.dcm(floor.frame) + Matrix([ + [cos(q0_C1(t))*cos(q0_C2(t)), sin(q0_C1(t))*cos(q0_C2(t)), -sin(q0_C2(t))], + [ -sin(q0_C1(t)), cos(q0_C1(t)), 0], + [sin(q0_C2(t))*cos(q0_C1(t)), sin(q0_C1(t))*sin(q0_C2(t)), cos(q0_C2(t))]]) + + The position of the flag's center of mass is found with: + + >>> flag.masscenter.pos_from(floor.masscenter) + q1_C1(t)*floor_frame.z + (r + q1_C2(t))*tube_frame.y + w*flag_frame.y - l*flag_frame.z + + The angular velocities of the two tubes can be computed with respect to the + floor. + + >>> tube.frame.ang_vel_in(floor.frame) + u0_C1(t)*floor_frame.z + >>> flag.frame.ang_vel_in(floor.frame) + u0_C1(t)*floor_frame.z + u0_C2(t)*tube_frame.y + + Finally, the linear velocities of the two tube centers of mass can be + computed with respect to the floor, while expressed in the tube's frame. + + >>> tube.masscenter.vel(floor.frame).to_matrix(tube.frame) + Matrix([ + [ 0], + [ 0], + [u1_C1(t)]]) + >>> flag.masscenter.vel(floor.frame).to_matrix(tube.frame).simplify() + Matrix([ + [-l*u0_C2(t)*cos(q0_C2(t)) - r*u0_C1(t) - w*u0_C1(t) - q1_C2(t)*u0_C1(t)], + [ -l*u0_C1(t)*sin(q0_C2(t)) + Derivative(q1_C2(t), t)], + [ l*u0_C2(t)*sin(q0_C2(t)) + u1_C1(t)]]) + + """ + + def __init__(self, name, parent, child, rotation_coordinate=None, + translation_coordinate=None, rotation_speed=None, + translation_speed=None, parent_point=None, child_point=None, + parent_interframe=None, child_interframe=None, + joint_axis=None): + self._joint_axis = joint_axis + coordinates = (rotation_coordinate, translation_coordinate) + speeds = (rotation_speed, translation_speed) + super().__init__(name, parent, child, coordinates, speeds, + parent_point, child_point, + parent_interframe=parent_interframe, + child_interframe=child_interframe) + + def __str__(self): + return (f'CylindricalJoint: {self.name} parent: {self.parent} ' + f'child: {self.child}') + + @property + def joint_axis(self): + """Axis about and along which the rotation and translation occurs.""" + return self._joint_axis + + @property + def rotation_coordinate(self): + """Generalized coordinate corresponding to the rotation angle.""" + return self.coordinates[0] + + @property + def translation_coordinate(self): + """Generalized coordinate corresponding to the translation distance.""" + return self.coordinates[1] + + @property + def rotation_speed(self): + """Generalized speed corresponding to the angular velocity.""" + return self.speeds[0] + + @property + def translation_speed(self): + """Generalized speed corresponding to the translation velocity.""" + return self.speeds[1] + + def _generate_coordinates(self, coordinates): + return self._fill_coordinate_list(coordinates, 2, 'q') + + def _generate_speeds(self, speeds): + return self._fill_coordinate_list(speeds, 2, 'u') + + def _orient_frames(self): + self._joint_axis = self._axis(self.joint_axis, self.parent_interframe) + self.child_interframe.orient_axis( + self.parent_interframe, self.joint_axis, self.rotation_coordinate) + + def _set_angular_velocity(self): + self.child_interframe.set_ang_vel( + self.parent_interframe, + self.rotation_speed * self.joint_axis.normalize()) + + def _set_linear_velocity(self): + self.child_point.set_pos( + self.parent_point, + self.translation_coordinate * self.joint_axis.normalize()) + self.parent_point.set_vel(self._parent_frame, 0) + self.child_point.set_vel(self._child_frame, 0) + self.child_point.set_vel( + self._parent_frame, + self.translation_speed * self.joint_axis.normalize()) + self.child.masscenter.v2pt_theory(self.child_point, self._parent_frame, + self.child_interframe) + + +class PlanarJoint(Joint): + """Planar Joint. + + .. raw:: html + :file: ../../../doc/src/modules/physics/mechanics/api/PlanarJoint.svg + + Explanation + =========== + + A planar joint is defined such that the child body translates over a fixed + plane of the parent body as well as rotate about the rotation axis, which + is perpendicular to that plane. The origin of this plane is the + ``parent_point`` and the plane is spanned by two nonparallel planar vectors. + The location of the ``child_point`` is based on the planar vectors + ($\\vec{v}_1$, $\\vec{v}_2$) and generalized coordinates ($q_1$, $q_2$), + i.e. $\\vec{r} = q_1 \\hat{v}_1 + q_2 \\hat{v}_2$. The direction cosine + matrix between the ``child_interframe`` and ``parent_interframe`` is formed + using a simple rotation ($q_0$) about the rotation axis. + + In order to simplify the definition of the ``PlanarJoint``, the + ``rotation_axis`` and ``planar_vectors`` are set to be the unit vectors of + the ``parent_interframe`` according to the table below. This ensures that + you can only define these vectors by creating a separate frame and supplying + that as the interframe. If you however would only like to supply the normals + of the plane with respect to the parent and child bodies, then you can also + supply those to the ``parent_interframe`` and ``child_interframe`` + arguments. An example of both of these cases is in the examples section + below and the page on the joints framework provides a more detailed + explanation of the intermediate frames. + + .. list-table:: + + * - ``rotation_axis`` + - ``parent_interframe.x`` + * - ``planar_vectors[0]`` + - ``parent_interframe.y`` + * - ``planar_vectors[1]`` + - ``parent_interframe.z`` + + Parameters + ========== + + name : string + A unique name for the joint. + parent : Particle or RigidBody or Body + The parent body of joint. + child : Particle or RigidBody or Body + The child body of joint. + rotation_coordinate : dynamicsymbol, optional + Generalized coordinate corresponding to the rotation angle. The default + value is ``dynamicsymbols(f'q0_{joint.name}')``. + planar_coordinates : iterable of dynamicsymbols, optional + Two generalized coordinates used for the planar translation. The default + value is ``dynamicsymbols(f'q1_{joint.name} q2_{joint.name}')``. + rotation_speed : dynamicsymbol, optional + Generalized speed corresponding to the angular velocity. The default + value is ``dynamicsymbols(f'u0_{joint.name}')``. + planar_speeds : dynamicsymbols, optional + Two generalized speeds used for the planar translation velocity. The + default value is ``dynamicsymbols(f'u1_{joint.name} u2_{joint.name}')``. + parent_point : Point or Vector, optional + Attachment point where the joint is fixed to the parent body. If a + vector is provided, then the attachment point is computed by adding the + vector to the body's mass center. The default value is the parent's mass + center. + child_point : Point or Vector, optional + Attachment point where the joint is fixed to the child body. If a + vector is provided, then the attachment point is computed by adding the + vector to the body's mass center. The default value is the child's mass + center. + parent_interframe : ReferenceFrame, optional + Intermediate frame of the parent body with respect to which the joint + transformation is formulated. If a Vector is provided then an interframe + is created which aligns its X axis with the given vector. The default + value is the parent's own frame. + child_interframe : ReferenceFrame, optional + Intermediate frame of the child body with respect to which the joint + transformation is formulated. If a Vector is provided then an interframe + is created which aligns its X axis with the given vector. The default + value is the child's own frame. + + Attributes + ========== + + name : string + The joint's name. + parent : Particle or RigidBody or Body + The joint's parent body. + child : Particle or RigidBody or Body + The joint's child body. + rotation_coordinate : dynamicsymbol + Generalized coordinate corresponding to the rotation angle. + planar_coordinates : Matrix + Two generalized coordinates used for the planar translation. + rotation_speed : dynamicsymbol + Generalized speed corresponding to the angular velocity. + planar_speeds : Matrix + Two generalized speeds used for the planar translation velocity. + coordinates : Matrix + Matrix of the joint's generalized coordinates. + speeds : Matrix + Matrix of the joint's generalized speeds. + parent_point : Point + Attachment point where the joint is fixed to the parent body. + child_point : Point + Attachment point where the joint is fixed to the child body. + parent_interframe : ReferenceFrame + Intermediate frame of the parent body with respect to which the joint + transformation is formulated. + child_interframe : ReferenceFrame + Intermediate frame of the child body with respect to which the joint + transformation is formulated. + kdes : Matrix + Kinematical differential equations of the joint. + rotation_axis : Vector + The axis about which the rotation occurs. + planar_vectors : list + The vectors that describe the planar translation directions. + + Examples + ========= + + A single planar joint is created between two bodies and has the following + basic attributes: + + >>> from sympy.physics.mechanics import RigidBody, PlanarJoint + >>> parent = RigidBody('P') + >>> parent + P + >>> child = RigidBody('C') + >>> child + C + >>> joint = PlanarJoint('PC', parent, child) + >>> joint + PlanarJoint: PC parent: P child: C + >>> joint.name + 'PC' + >>> joint.parent + P + >>> joint.child + C + >>> joint.parent_point + P_masscenter + >>> joint.child_point + C_masscenter + >>> joint.rotation_axis + P_frame.x + >>> joint.planar_vectors + [P_frame.y, P_frame.z] + >>> joint.rotation_coordinate + q0_PC(t) + >>> joint.planar_coordinates + Matrix([ + [q1_PC(t)], + [q2_PC(t)]]) + >>> joint.coordinates + Matrix([ + [q0_PC(t)], + [q1_PC(t)], + [q2_PC(t)]]) + >>> joint.rotation_speed + u0_PC(t) + >>> joint.planar_speeds + Matrix([ + [u1_PC(t)], + [u2_PC(t)]]) + >>> joint.speeds + Matrix([ + [u0_PC(t)], + [u1_PC(t)], + [u2_PC(t)]]) + >>> child.frame.ang_vel_in(parent.frame) + u0_PC(t)*P_frame.x + >>> child.frame.dcm(parent.frame) + Matrix([ + [1, 0, 0], + [0, cos(q0_PC(t)), sin(q0_PC(t))], + [0, -sin(q0_PC(t)), cos(q0_PC(t))]]) + >>> joint.child_point.pos_from(joint.parent_point) + q1_PC(t)*P_frame.y + q2_PC(t)*P_frame.z + >>> child.masscenter.vel(parent.frame) + u1_PC(t)*P_frame.y + u2_PC(t)*P_frame.z + + To further demonstrate the use of the planar joint, the kinematics of a + block sliding on a slope, can be created as follows. + + >>> from sympy import symbols + >>> from sympy.physics.mechanics import PlanarJoint, RigidBody, ReferenceFrame + >>> a, d, h = symbols('a d h') + + First create bodies to represent the slope and the block. + + >>> ground = RigidBody('G') + >>> block = RigidBody('B') + + To define the slope you can either define the plane by specifying the + ``planar_vectors`` or/and the ``rotation_axis``. However it is advisable to + create a rotated intermediate frame, so that the ``parent_vectors`` and + ``rotation_axis`` will be the unit vectors of this intermediate frame. + + >>> slope = ReferenceFrame('A') + >>> slope.orient_axis(ground.frame, ground.y, a) + + The planar joint can be created using these bodies and intermediate frame. + We can specify the origin of the slope to be ``d`` above the slope's center + of mass and the block's center of mass to be a distance ``h`` above the + slope's surface. Note that we can specify the normal of the plane using the + rotation axis argument. + + >>> joint = PlanarJoint('PC', ground, block, parent_point=d * ground.x, + ... child_point=-h * block.x, parent_interframe=slope) + + Once the joint is established the kinematics of the bodies can be accessed. + First the ``rotation_axis``, which is normal to the plane and the + ``plane_vectors``, can be found. + + >>> joint.rotation_axis + A.x + >>> joint.planar_vectors + [A.y, A.z] + + The direction cosine matrix of the block with respect to the ground can be + found with: + + >>> block.frame.dcm(ground.frame) + Matrix([ + [ cos(a), 0, -sin(a)], + [sin(a)*sin(q0_PC(t)), cos(q0_PC(t)), sin(q0_PC(t))*cos(a)], + [sin(a)*cos(q0_PC(t)), -sin(q0_PC(t)), cos(a)*cos(q0_PC(t))]]) + + The angular velocity of the block can be computed with respect to the + ground. + + >>> block.frame.ang_vel_in(ground.frame) + u0_PC(t)*A.x + + The position of the block's center of mass can be found with: + + >>> block.masscenter.pos_from(ground.masscenter) + d*G_frame.x + h*B_frame.x + q1_PC(t)*A.y + q2_PC(t)*A.z + + Finally, the linear velocity of the block's center of mass can be + computed with respect to the ground. + + >>> block.masscenter.vel(ground.frame) + u1_PC(t)*A.y + u2_PC(t)*A.z + + In some cases it could be your preference to only define the normals of the + plane with respect to both bodies. This can most easily be done by supplying + vectors to the ``interframe`` arguments. What will happen in this case is + that an interframe will be created with its ``x`` axis aligned with the + provided vector. For a further explanation of how this is done see the notes + of the ``Joint`` class. In the code below, the above example (with the block + on the slope) is recreated by supplying vectors to the interframe arguments. + Note that the previously described option is however more computationally + efficient, because the algorithm now has to compute the rotation angle + between the provided vector and the 'x' axis. + + >>> from sympy import symbols, cos, sin + >>> from sympy.physics.mechanics import PlanarJoint, RigidBody + >>> a, d, h = symbols('a d h') + >>> ground = RigidBody('G') + >>> block = RigidBody('B') + >>> joint = PlanarJoint( + ... 'PC', ground, block, parent_point=d * ground.x, + ... child_point=-h * block.x, child_interframe=block.x, + ... parent_interframe=cos(a) * ground.x + sin(a) * ground.z) + >>> block.frame.dcm(ground.frame).simplify() + Matrix([ + [ cos(a), 0, sin(a)], + [-sin(a)*sin(q0_PC(t)), cos(q0_PC(t)), sin(q0_PC(t))*cos(a)], + [-sin(a)*cos(q0_PC(t)), -sin(q0_PC(t)), cos(a)*cos(q0_PC(t))]]) + + """ + + def __init__(self, name, parent, child, rotation_coordinate=None, + planar_coordinates=None, rotation_speed=None, + planar_speeds=None, parent_point=None, child_point=None, + parent_interframe=None, child_interframe=None): + # A ready to merge implementation of setting the planar_vectors and + # rotation_axis was added and removed in PR #24046 + coordinates = (rotation_coordinate, planar_coordinates) + speeds = (rotation_speed, planar_speeds) + super().__init__(name, parent, child, coordinates, speeds, + parent_point, child_point, + parent_interframe=parent_interframe, + child_interframe=child_interframe) + + def __str__(self): + return (f'PlanarJoint: {self.name} parent: {self.parent} ' + f'child: {self.child}') + + @property + def rotation_coordinate(self): + """Generalized coordinate corresponding to the rotation angle.""" + return self.coordinates[0] + + @property + def planar_coordinates(self): + """Two generalized coordinates used for the planar translation.""" + return self.coordinates[1:, 0] + + @property + def rotation_speed(self): + """Generalized speed corresponding to the angular velocity.""" + return self.speeds[0] + + @property + def planar_speeds(self): + """Two generalized speeds used for the planar translation velocity.""" + return self.speeds[1:, 0] + + @property + def rotation_axis(self): + """The axis about which the rotation occurs.""" + return self.parent_interframe.x + + @property + def planar_vectors(self): + """The vectors that describe the planar translation directions.""" + return [self.parent_interframe.y, self.parent_interframe.z] + + def _generate_coordinates(self, coordinates): + rotation_speed = self._fill_coordinate_list(coordinates[0], 1, 'q', + number_single=True) + planar_speeds = self._fill_coordinate_list(coordinates[1], 2, 'q', 1) + return rotation_speed.col_join(planar_speeds) + + def _generate_speeds(self, speeds): + rotation_speed = self._fill_coordinate_list(speeds[0], 1, 'u', + number_single=True) + planar_speeds = self._fill_coordinate_list(speeds[1], 2, 'u', 1) + return rotation_speed.col_join(planar_speeds) + + def _orient_frames(self): + self.child_interframe.orient_axis( + self.parent_interframe, self.rotation_axis, + self.rotation_coordinate) + + def _set_angular_velocity(self): + self.child_interframe.set_ang_vel( + self.parent_interframe, + self.rotation_speed * self.rotation_axis) + + def _set_linear_velocity(self): + self.child_point.set_pos( + self.parent_point, + self.planar_coordinates[0] * self.planar_vectors[0] + + self.planar_coordinates[1] * self.planar_vectors[1]) + self.parent_point.set_vel(self.parent_interframe, 0) + self.child_point.set_vel(self.child_interframe, 0) + self.child_point.set_vel( + self._parent_frame, self.planar_speeds[0] * self.planar_vectors[0] + + self.planar_speeds[1] * self.planar_vectors[1]) + self.child.masscenter.v2pt_theory(self.child_point, self._parent_frame, + self._child_frame) + + +class SphericalJoint(Joint): + """Spherical (Ball-and-Socket) Joint. + + .. image:: SphericalJoint.svg + :align: center + :width: 600 + + Explanation + =========== + + A spherical joint is defined such that the child body is free to rotate in + any direction, without allowing a translation of the ``child_point``. As can + also be seen in the image, the ``parent_point`` and ``child_point`` are + fixed on top of each other, i.e. the ``joint_point``. This rotation is + defined using the :func:`parent_interframe.orient(child_interframe, + rot_type, amounts, rot_order) + ` method. The default + rotation consists of three relative rotations, i.e. body-fixed rotations. + Based on the direction cosine matrix following from these rotations, the + angular velocity is computed based on the generalized coordinates and + generalized speeds. + + Parameters + ========== + + name : string + A unique name for the joint. + parent : Particle or RigidBody or Body + The parent body of joint. + child : Particle or RigidBody or Body + The child body of joint. + coordinates: iterable of dynamicsymbols, optional + Generalized coordinates of the joint. + speeds : iterable of dynamicsymbols, optional + Generalized speeds of joint. + parent_point : Point or Vector, optional + Attachment point where the joint is fixed to the parent body. If a + vector is provided, then the attachment point is computed by adding the + vector to the body's mass center. The default value is the parent's mass + center. + child_point : Point or Vector, optional + Attachment point where the joint is fixed to the child body. If a + vector is provided, then the attachment point is computed by adding the + vector to the body's mass center. The default value is the child's mass + center. + parent_interframe : ReferenceFrame, optional + Intermediate frame of the parent body with respect to which the joint + transformation is formulated. If a Vector is provided then an interframe + is created which aligns its X axis with the given vector. The default + value is the parent's own frame. + child_interframe : ReferenceFrame, optional + Intermediate frame of the child body with respect to which the joint + transformation is formulated. If a Vector is provided then an interframe + is created which aligns its X axis with the given vector. The default + value is the child's own frame. + rot_type : str, optional + The method used to generate the direction cosine matrix. Supported + methods are: + + - ``'Body'``: three successive rotations about new intermediate axes, + also called "Euler and Tait-Bryan angles" + - ``'Space'``: three successive rotations about the parent frames' unit + vectors + + The default method is ``'Body'``. + amounts : + Expressions defining the rotation angles or direction cosine matrix. + These must match the ``rot_type``. See examples below for details. The + input types are: + + - ``'Body'``: 3-tuple of expressions, symbols, or functions + - ``'Space'``: 3-tuple of expressions, symbols, or functions + + The default amounts are the given ``coordinates``. + rot_order : str or int, optional + If applicable, the order of the successive of rotations. The string + ``'123'`` and integer ``123`` are equivalent, for example. Required for + ``'Body'`` and ``'Space'``. The default value is ``123``. + + Attributes + ========== + + name : string + The joint's name. + parent : Particle or RigidBody or Body + The joint's parent body. + child : Particle or RigidBody or Body + The joint's child body. + coordinates : Matrix + Matrix of the joint's generalized coordinates. + speeds : Matrix + Matrix of the joint's generalized speeds. + parent_point : Point + Attachment point where the joint is fixed to the parent body. + child_point : Point + Attachment point where the joint is fixed to the child body. + parent_interframe : ReferenceFrame + Intermediate frame of the parent body with respect to which the joint + transformation is formulated. + child_interframe : ReferenceFrame + Intermediate frame of the child body with respect to which the joint + transformation is formulated. + kdes : Matrix + Kinematical differential equations of the joint. + + Examples + ========= + + A single spherical joint is created from two bodies and has the following + basic attributes: + + >>> from sympy.physics.mechanics import RigidBody, SphericalJoint + >>> parent = RigidBody('P') + >>> parent + P + >>> child = RigidBody('C') + >>> child + C + >>> joint = SphericalJoint('PC', parent, child) + >>> joint + SphericalJoint: PC parent: P child: C + >>> joint.name + 'PC' + >>> joint.parent + P + >>> joint.child + C + >>> joint.parent_point + P_masscenter + >>> joint.child_point + C_masscenter + >>> joint.parent_interframe + P_frame + >>> joint.child_interframe + C_frame + >>> joint.coordinates + Matrix([ + [q0_PC(t)], + [q1_PC(t)], + [q2_PC(t)]]) + >>> joint.speeds + Matrix([ + [u0_PC(t)], + [u1_PC(t)], + [u2_PC(t)]]) + >>> child.frame.ang_vel_in(parent.frame).to_matrix(child.frame) + Matrix([ + [ u0_PC(t)*cos(q1_PC(t))*cos(q2_PC(t)) + u1_PC(t)*sin(q2_PC(t))], + [-u0_PC(t)*sin(q2_PC(t))*cos(q1_PC(t)) + u1_PC(t)*cos(q2_PC(t))], + [ u0_PC(t)*sin(q1_PC(t)) + u2_PC(t)]]) + >>> child.frame.x.to_matrix(parent.frame) + Matrix([ + [ cos(q1_PC(t))*cos(q2_PC(t))], + [sin(q0_PC(t))*sin(q1_PC(t))*cos(q2_PC(t)) + sin(q2_PC(t))*cos(q0_PC(t))], + [sin(q0_PC(t))*sin(q2_PC(t)) - sin(q1_PC(t))*cos(q0_PC(t))*cos(q2_PC(t))]]) + >>> joint.child_point.pos_from(joint.parent_point) + 0 + + To further demonstrate the use of the spherical joint, the kinematics of a + spherical joint with a ZXZ rotation can be created as follows. + + >>> from sympy import symbols + >>> from sympy.physics.mechanics import RigidBody, SphericalJoint + >>> l1 = symbols('l1') + + First create bodies to represent the fixed floor and a pendulum bob. + + >>> floor = RigidBody('F') + >>> bob = RigidBody('B') + + The joint will connect the bob to the floor, with the joint located at a + distance of ``l1`` from the child's center of mass and the rotation set to a + body-fixed ZXZ rotation. + + >>> joint = SphericalJoint('S', floor, bob, child_point=l1 * bob.y, + ... rot_type='body', rot_order='ZXZ') + + Now that the joint is established, the kinematics of the connected body can + be accessed. + + The position of the bob's masscenter is found with: + + >>> bob.masscenter.pos_from(floor.masscenter) + - l1*B_frame.y + + The angular velocities of the pendulum link can be computed with respect to + the floor. + + >>> bob.frame.ang_vel_in(floor.frame).to_matrix( + ... floor.frame).simplify() + Matrix([ + [u1_S(t)*cos(q0_S(t)) + u2_S(t)*sin(q0_S(t))*sin(q1_S(t))], + [u1_S(t)*sin(q0_S(t)) - u2_S(t)*sin(q1_S(t))*cos(q0_S(t))], + [ u0_S(t) + u2_S(t)*cos(q1_S(t))]]) + + Finally, the linear velocity of the bob's center of mass can be computed. + + >>> bob.masscenter.vel(floor.frame).to_matrix(bob.frame) + Matrix([ + [ l1*(u0_S(t)*cos(q1_S(t)) + u2_S(t))], + [ 0], + [-l1*(u0_S(t)*sin(q1_S(t))*sin(q2_S(t)) + u1_S(t)*cos(q2_S(t)))]]) + + """ + def __init__(self, name, parent, child, coordinates=None, speeds=None, + parent_point=None, child_point=None, parent_interframe=None, + child_interframe=None, rot_type='BODY', amounts=None, + rot_order=123): + self._rot_type = rot_type + self._amounts = amounts + self._rot_order = rot_order + super().__init__(name, parent, child, coordinates, speeds, + parent_point, child_point, + parent_interframe=parent_interframe, + child_interframe=child_interframe) + + def __str__(self): + return (f'SphericalJoint: {self.name} parent: {self.parent} ' + f'child: {self.child}') + + def _generate_coordinates(self, coordinates): + return self._fill_coordinate_list(coordinates, 3, 'q') + + def _generate_speeds(self, speeds): + return self._fill_coordinate_list(speeds, len(self.coordinates), 'u') + + def _orient_frames(self): + supported_rot_types = ('BODY', 'SPACE') + if self._rot_type.upper() not in supported_rot_types: + raise NotImplementedError( + f'Rotation type "{self._rot_type}" is not implemented. ' + f'Implemented rotation types are: {supported_rot_types}') + amounts = self.coordinates if self._amounts is None else self._amounts + self.child_interframe.orient(self.parent_interframe, self._rot_type, + amounts, self._rot_order) + + def _set_angular_velocity(self): + t = dynamicsymbols._t + vel = self.child_interframe.ang_vel_in(self.parent_interframe).xreplace( + {q.diff(t): u for q, u in zip(self.coordinates, self.speeds)} + ) + self.child_interframe.set_ang_vel(self.parent_interframe, vel) + + def _set_linear_velocity(self): + self.child_point.set_pos(self.parent_point, 0) + self.parent_point.set_vel(self._parent_frame, 0) + self.child_point.set_vel(self._child_frame, 0) + self.child.masscenter.v2pt_theory(self.parent_point, self._parent_frame, + self._child_frame) + + +class WeldJoint(Joint): + """Weld Joint. + + .. raw:: html + :file: ../../../doc/src/modules/physics/mechanics/api/WeldJoint.svg + + Explanation + =========== + + A weld joint is defined such that there is no relative motion between the + child and parent bodies. The direction cosine matrix between the attachment + frame (``parent_interframe`` and ``child_interframe``) is the identity + matrix and the attachment points (``parent_point`` and ``child_point``) are + coincident. The page on the joints framework gives a more detailed + explanation of the intermediate frames. + + Parameters + ========== + + name : string + A unique name for the joint. + parent : Particle or RigidBody or Body + The parent body of joint. + child : Particle or RigidBody or Body + The child body of joint. + parent_point : Point or Vector, optional + Attachment point where the joint is fixed to the parent body. If a + vector is provided, then the attachment point is computed by adding the + vector to the body's mass center. The default value is the parent's mass + center. + child_point : Point or Vector, optional + Attachment point where the joint is fixed to the child body. If a + vector is provided, then the attachment point is computed by adding the + vector to the body's mass center. The default value is the child's mass + center. + parent_interframe : ReferenceFrame, optional + Intermediate frame of the parent body with respect to which the joint + transformation is formulated. If a Vector is provided then an interframe + is created which aligns its X axis with the given vector. The default + value is the parent's own frame. + child_interframe : ReferenceFrame, optional + Intermediate frame of the child body with respect to which the joint + transformation is formulated. If a Vector is provided then an interframe + is created which aligns its X axis with the given vector. The default + value is the child's own frame. + + Attributes + ========== + + name : string + The joint's name. + parent : Particle or RigidBody or Body + The joint's parent body. + child : Particle or RigidBody or Body + The joint's child body. + coordinates : Matrix + Matrix of the joint's generalized coordinates. The default value is + ``dynamicsymbols(f'q_{joint.name}')``. + speeds : Matrix + Matrix of the joint's generalized speeds. The default value is + ``dynamicsymbols(f'u_{joint.name}')``. + parent_point : Point + Attachment point where the joint is fixed to the parent body. + child_point : Point + Attachment point where the joint is fixed to the child body. + parent_interframe : ReferenceFrame + Intermediate frame of the parent body with respect to which the joint + transformation is formulated. + child_interframe : ReferenceFrame + Intermediate frame of the child body with respect to which the joint + transformation is formulated. + kdes : Matrix + Kinematical differential equations of the joint. + + Examples + ========= + + A single weld joint is created from two bodies and has the following basic + attributes: + + >>> from sympy.physics.mechanics import RigidBody, WeldJoint + >>> parent = RigidBody('P') + >>> parent + P + >>> child = RigidBody('C') + >>> child + C + >>> joint = WeldJoint('PC', parent, child) + >>> joint + WeldJoint: PC parent: P child: C + >>> joint.name + 'PC' + >>> joint.parent + P + >>> joint.child + C + >>> joint.parent_point + P_masscenter + >>> joint.child_point + C_masscenter + >>> joint.coordinates + Matrix(0, 0, []) + >>> joint.speeds + Matrix(0, 0, []) + >>> child.frame.ang_vel_in(parent.frame) + 0 + >>> child.frame.dcm(parent.frame) + Matrix([ + [1, 0, 0], + [0, 1, 0], + [0, 0, 1]]) + >>> joint.child_point.pos_from(joint.parent_point) + 0 + + To further demonstrate the use of the weld joint, two relatively-fixed + bodies rotated by a quarter turn about the Y axis can be created as follows: + + >>> from sympy import symbols, pi + >>> from sympy.physics.mechanics import ReferenceFrame, RigidBody, WeldJoint + >>> l1, l2 = symbols('l1 l2') + + First create the bodies to represent the parent and rotated child body. + + >>> parent = RigidBody('P') + >>> child = RigidBody('C') + + Next the intermediate frame specifying the fixed rotation with respect to + the parent can be created. + + >>> rotated_frame = ReferenceFrame('Pr') + >>> rotated_frame.orient_axis(parent.frame, parent.y, pi / 2) + + The weld between the parent body and child body is located at a distance + ``l1`` from the parent's center of mass in the X direction and ``l2`` from + the child's center of mass in the child's negative X direction. + + >>> weld = WeldJoint('weld', parent, child, parent_point=l1 * parent.x, + ... child_point=-l2 * child.x, + ... parent_interframe=rotated_frame) + + Now that the joint has been established, the kinematics of the bodies can be + accessed. The direction cosine matrix of the child body with respect to the + parent can be found: + + >>> child.frame.dcm(parent.frame) + Matrix([ + [0, 0, -1], + [0, 1, 0], + [1, 0, 0]]) + + As can also been seen from the direction cosine matrix, the parent X axis is + aligned with the child's Z axis: + >>> parent.x == child.z + True + + The position of the child's center of mass with respect to the parent's + center of mass can be found with: + + >>> child.masscenter.pos_from(parent.masscenter) + l1*P_frame.x + l2*C_frame.x + + The angular velocity of the child with respect to the parent is 0 as one + would expect. + + >>> child.frame.ang_vel_in(parent.frame) + 0 + + """ + + def __init__(self, name, parent, child, parent_point=None, child_point=None, + parent_interframe=None, child_interframe=None): + super().__init__(name, parent, child, [], [], parent_point, + child_point, parent_interframe=parent_interframe, + child_interframe=child_interframe) + self._kdes = Matrix(1, 0, []).T # Removes stackability problems #10770 + + def __str__(self): + return (f'WeldJoint: {self.name} parent: {self.parent} ' + f'child: {self.child}') + + def _generate_coordinates(self, coordinate): + return Matrix() + + def _generate_speeds(self, speed): + return Matrix() + + def _orient_frames(self): + self.child_interframe.orient_axis(self.parent_interframe, + self.parent_interframe.x, 0) + + def _set_angular_velocity(self): + self.child_interframe.set_ang_vel(self.parent_interframe, 0) + + def _set_linear_velocity(self): + self.child_point.set_pos(self.parent_point, 0) + self.parent_point.set_vel(self._parent_frame, 0) + self.child_point.set_vel(self._child_frame, 0) + self.child.masscenter.set_vel(self._parent_frame, 0) diff --git a/lib/python3.12/site-packages/sympy/physics/mechanics/jointsmethod.py b/lib/python3.12/site-packages/sympy/physics/mechanics/jointsmethod.py new file mode 100644 index 0000000000000000000000000000000000000000..df7bd56360072feb57a65e5f78c2d116f0d4842d --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/mechanics/jointsmethod.py @@ -0,0 +1,318 @@ +from sympy.physics.mechanics import (Body, Lagrangian, KanesMethod, LagrangesMethod, + RigidBody, Particle) +from sympy.physics.mechanics.body_base import BodyBase +from sympy.physics.mechanics.method import _Methods +from sympy import Matrix +from sympy.utilities.exceptions import sympy_deprecation_warning + +__all__ = ['JointsMethod'] + + +class JointsMethod(_Methods): + """Method for formulating the equations of motion using a set of interconnected bodies with joints. + + .. deprecated:: 1.13 + The JointsMethod class is deprecated. Its functionality has been + replaced by the new :class:`~.System` class. + + Parameters + ========== + + newtonion : Body or ReferenceFrame + The newtonion(inertial) frame. + *joints : Joint + The joints in the system + + Attributes + ========== + + q, u : iterable + Iterable of the generalized coordinates and speeds + bodies : iterable + Iterable of Body objects in the system. + loads : iterable + Iterable of (Point, vector) or (ReferenceFrame, vector) tuples + describing the forces on the system. + mass_matrix : Matrix, shape(n, n) + The system's mass matrix + forcing : Matrix, shape(n, 1) + The system's forcing vector + mass_matrix_full : Matrix, shape(2*n, 2*n) + The "mass matrix" for the u's and q's + forcing_full : Matrix, shape(2*n, 1) + The "forcing vector" for the u's and q's + method : KanesMethod or Lagrange's method + Method's object. + kdes : iterable + Iterable of kde in they system. + + Examples + ======== + + As Body and JointsMethod have been deprecated, the following examples are + for illustrative purposes only. The functionality of Body is fully captured + by :class:`~.RigidBody` and :class:`~.Particle` and the functionality of + JointsMethod is fully captured by :class:`~.System`. To ignore the + deprecation warning we can use the ignore_warnings context manager. + + >>> from sympy.utilities.exceptions import ignore_warnings + + This is a simple example for a one degree of freedom translational + spring-mass-damper. + + >>> from sympy import symbols + >>> from sympy.physics.mechanics import Body, JointsMethod, PrismaticJoint + >>> from sympy.physics.vector import dynamicsymbols + >>> c, k = symbols('c k') + >>> x, v = dynamicsymbols('x v') + >>> with ignore_warnings(DeprecationWarning): + ... wall = Body('W') + ... body = Body('B') + >>> J = PrismaticJoint('J', wall, body, coordinates=x, speeds=v) + >>> wall.apply_force(c*v*wall.x, reaction_body=body) + >>> wall.apply_force(k*x*wall.x, reaction_body=body) + >>> with ignore_warnings(DeprecationWarning): + ... method = JointsMethod(wall, J) + >>> method.form_eoms() + Matrix([[-B_mass*Derivative(v(t), t) - c*v(t) - k*x(t)]]) + >>> M = method.mass_matrix_full + >>> F = method.forcing_full + >>> rhs = M.LUsolve(F) + >>> rhs + Matrix([ + [ v(t)], + [(-c*v(t) - k*x(t))/B_mass]]) + + Notes + ===== + + ``JointsMethod`` currently only works with systems that do not have any + configuration or motion constraints. + + """ + + def __init__(self, newtonion, *joints): + sympy_deprecation_warning( + """ + The JointsMethod class is deprecated. + Its functionality has been replaced by the new System class. + """, + deprecated_since_version="1.13", + active_deprecations_target="deprecated-mechanics-jointsmethod" + ) + if isinstance(newtonion, BodyBase): + self.frame = newtonion.frame + else: + self.frame = newtonion + + self._joints = joints + self._bodies = self._generate_bodylist() + self._loads = self._generate_loadlist() + self._q = self._generate_q() + self._u = self._generate_u() + self._kdes = self._generate_kdes() + + self._method = None + + @property + def bodies(self): + """List of bodies in they system.""" + return self._bodies + + @property + def loads(self): + """List of loads on the system.""" + return self._loads + + @property + def q(self): + """List of the generalized coordinates.""" + return self._q + + @property + def u(self): + """List of the generalized speeds.""" + return self._u + + @property + def kdes(self): + """List of the generalized coordinates.""" + return self._kdes + + @property + def forcing_full(self): + """The "forcing vector" for the u's and q's.""" + return self.method.forcing_full + + @property + def mass_matrix_full(self): + """The "mass matrix" for the u's and q's.""" + return self.method.mass_matrix_full + + @property + def mass_matrix(self): + """The system's mass matrix.""" + return self.method.mass_matrix + + @property + def forcing(self): + """The system's forcing vector.""" + return self.method.forcing + + @property + def method(self): + """Object of method used to form equations of systems.""" + return self._method + + def _generate_bodylist(self): + bodies = [] + for joint in self._joints: + if joint.child not in bodies: + bodies.append(joint.child) + if joint.parent not in bodies: + bodies.append(joint.parent) + return bodies + + def _generate_loadlist(self): + load_list = [] + for body in self.bodies: + if isinstance(body, Body): + load_list.extend(body.loads) + return load_list + + def _generate_q(self): + q_ind = [] + for joint in self._joints: + for coordinate in joint.coordinates: + if coordinate in q_ind: + raise ValueError('Coordinates of joints should be unique.') + q_ind.append(coordinate) + return Matrix(q_ind) + + def _generate_u(self): + u_ind = [] + for joint in self._joints: + for speed in joint.speeds: + if speed in u_ind: + raise ValueError('Speeds of joints should be unique.') + u_ind.append(speed) + return Matrix(u_ind) + + def _generate_kdes(self): + kd_ind = Matrix(1, 0, []).T + for joint in self._joints: + kd_ind = kd_ind.col_join(joint.kdes) + return kd_ind + + def _convert_bodies(self): + # Convert `Body` to `Particle` and `RigidBody` + bodylist = [] + for body in self.bodies: + if not isinstance(body, Body): + bodylist.append(body) + continue + if body.is_rigidbody: + rb = RigidBody(body.name, body.masscenter, body.frame, body.mass, + (body.central_inertia, body.masscenter)) + rb.potential_energy = body.potential_energy + bodylist.append(rb) + else: + part = Particle(body.name, body.masscenter, body.mass) + part.potential_energy = body.potential_energy + bodylist.append(part) + return bodylist + + def form_eoms(self, method=KanesMethod): + """Method to form system's equation of motions. + + Parameters + ========== + + method : Class + Class name of method. + + Returns + ======== + + Matrix + Vector of equations of motions. + + Examples + ======== + + As Body and JointsMethod have been deprecated, the following examples + are for illustrative purposes only. The functionality of Body is fully + captured by :class:`~.RigidBody` and :class:`~.Particle` and the + functionality of JointsMethod is fully captured by :class:`~.System`. To + ignore the deprecation warning we can use the ignore_warnings context + manager. + + >>> from sympy.utilities.exceptions import ignore_warnings + + This is a simple example for a one degree of freedom translational + spring-mass-damper. + + >>> from sympy import S, symbols + >>> from sympy.physics.mechanics import LagrangesMethod, dynamicsymbols, Body + >>> from sympy.physics.mechanics import PrismaticJoint, JointsMethod + >>> q = dynamicsymbols('q') + >>> qd = dynamicsymbols('q', 1) + >>> m, k, b = symbols('m k b') + >>> with ignore_warnings(DeprecationWarning): + ... wall = Body('W') + ... part = Body('P', mass=m) + >>> part.potential_energy = k * q**2 / S(2) + >>> J = PrismaticJoint('J', wall, part, coordinates=q, speeds=qd) + >>> wall.apply_force(b * qd * wall.x, reaction_body=part) + >>> with ignore_warnings(DeprecationWarning): + ... method = JointsMethod(wall, J) + >>> method.form_eoms(LagrangesMethod) + Matrix([[b*Derivative(q(t), t) + k*q(t) + m*Derivative(q(t), (t, 2))]]) + + We can also solve for the states using the 'rhs' method. + + >>> method.rhs() + Matrix([ + [ Derivative(q(t), t)], + [(-b*Derivative(q(t), t) - k*q(t))/m]]) + + """ + + bodylist = self._convert_bodies() + if issubclass(method, LagrangesMethod): #LagrangesMethod or similar + L = Lagrangian(self.frame, *bodylist) + self._method = method(L, self.q, self.loads, bodylist, self.frame) + else: #KanesMethod or similar + self._method = method(self.frame, q_ind=self.q, u_ind=self.u, kd_eqs=self.kdes, + forcelist=self.loads, bodies=bodylist) + soln = self.method._form_eoms() + return soln + + def rhs(self, inv_method=None): + """Returns equations that can be solved numerically. + + Parameters + ========== + + inv_method : str + The specific sympy inverse matrix calculation method to use. For a + list of valid methods, see + :meth:`~sympy.matrices.matrixbase.MatrixBase.inv` + + Returns + ======== + + Matrix + Numerically solvable equations. + + See Also + ======== + + sympy.physics.mechanics.kane.KanesMethod.rhs: + KanesMethod's rhs function. + sympy.physics.mechanics.lagrange.LagrangesMethod.rhs: + LagrangesMethod's rhs function. + + """ + + return self.method.rhs(inv_method=inv_method) diff --git a/lib/python3.12/site-packages/sympy/physics/mechanics/kane.py b/lib/python3.12/site-packages/sympy/physics/mechanics/kane.py new file mode 100644 index 0000000000000000000000000000000000000000..7edea5fa881cd89ae366c3141e575b00c0e5ac34 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/mechanics/kane.py @@ -0,0 +1,860 @@ +from sympy import zeros, Matrix, diff, eye +from sympy.core.sorting import default_sort_key +from sympy.physics.vector import (ReferenceFrame, dynamicsymbols, + partial_velocity) +from sympy.physics.mechanics.method import _Methods +from sympy.physics.mechanics.particle import Particle +from sympy.physics.mechanics.rigidbody import RigidBody +from sympy.physics.mechanics.functions import (msubs, find_dynamicsymbols, + _f_list_parser, + _validate_coordinates, + _parse_linear_solver) +from sympy.physics.mechanics.linearize import Linearizer +from sympy.utilities.iterables import iterable + +__all__ = ['KanesMethod'] + + +class KanesMethod(_Methods): + r"""Kane's method object. + + Explanation + =========== + + This object is used to do the "book-keeping" as you go through and form + equations of motion in the way Kane presents in: + Kane, T., Levinson, D. Dynamics Theory and Applications. 1985 McGraw-Hill + + The attributes are for equations in the form [M] udot = forcing. + + Attributes + ========== + + q, u : Matrix + Matrices of the generalized coordinates and speeds + bodies : iterable + Iterable of Particle and RigidBody objects in the system. + loads : iterable + Iterable of (Point, vector) or (ReferenceFrame, vector) tuples + describing the forces on the system. + auxiliary_eqs : Matrix + If applicable, the set of auxiliary Kane's + equations used to solve for non-contributing + forces. + mass_matrix : Matrix + The system's dynamics mass matrix: [k_d; k_dnh] + forcing : Matrix + The system's dynamics forcing vector: -[f_d; f_dnh] + mass_matrix_kin : Matrix + The "mass matrix" for kinematic differential equations: k_kqdot + forcing_kin : Matrix + The forcing vector for kinematic differential equations: -(k_ku*u + f_k) + mass_matrix_full : Matrix + The "mass matrix" for the u's and q's with dynamics and kinematics + forcing_full : Matrix + The "forcing vector" for the u's and q's with dynamics and kinematics + + Parameters + ========== + + frame : ReferenceFrame + The inertial reference frame for the system. + q_ind : iterable of dynamicsymbols + Independent generalized coordinates. + u_ind : iterable of dynamicsymbols + Independent generalized speeds. + kd_eqs : iterable of Expr, optional + Kinematic differential equations, which linearly relate the generalized + speeds to the time-derivatives of the generalized coordinates. + q_dependent : iterable of dynamicsymbols, optional + Dependent generalized coordinates. + configuration_constraints : iterable of Expr, optional + Constraints on the system's configuration, i.e. holonomic constraints. + u_dependent : iterable of dynamicsymbols, optional + Dependent generalized speeds. + velocity_constraints : iterable of Expr, optional + Constraints on the system's velocity, i.e. the combination of the + nonholonomic constraints and the time-derivative of the holonomic + constraints. + acceleration_constraints : iterable of Expr, optional + Constraints on the system's acceleration, by default these are the + time-derivative of the velocity constraints. + u_auxiliary : iterable of dynamicsymbols, optional + Auxiliary generalized speeds. + bodies : iterable of Particle and/or RigidBody, optional + The particles and rigid bodies in the system. + forcelist : iterable of tuple[Point | ReferenceFrame, Vector], optional + Forces and torques applied on the system. + explicit_kinematics : bool + Boolean whether the mass matrices and forcing vectors should use the + explicit form (default) or implicit form for kinematics. + See the notes for more details. + kd_eqs_solver : str, callable + Method used to solve the kinematic differential equations. If a string + is supplied, it should be a valid method that can be used with the + :meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is + supplied, it should have the format ``f(A, rhs)``, where it solves the + equations and returns the solution. The default utilizes LU solve. See + the notes for more information. + constraint_solver : str, callable + Method used to solve the velocity constraints. If a string is + supplied, it should be a valid method that can be used with the + :meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is + supplied, it should have the format ``f(A, rhs)``, where it solves the + equations and returns the solution. The default utilizes LU solve. See + the notes for more information. + + Notes + ===== + + The mass matrices and forcing vectors related to kinematic equations + are given in the explicit form by default. In other words, the kinematic + mass matrix is $\mathbf{k_{k\dot{q}}} = \mathbf{I}$. + In order to get the implicit form of those matrices/vectors, you can set the + ``explicit_kinematics`` attribute to ``False``. So $\mathbf{k_{k\dot{q}}}$ + is not necessarily an identity matrix. This can provide more compact + equations for non-simple kinematics. + + Two linear solvers can be supplied to ``KanesMethod``: one for solving the + kinematic differential equations and one to solve the velocity constraints. + Both of these sets of equations can be expressed as a linear system ``Ax = rhs``, + which have to be solved in order to obtain the equations of motion. + + The default solver ``'LU'``, which stands for LU solve, results relatively low + number of operations. The weakness of this method is that it can result in zero + division errors. + + If zero divisions are encountered, a possible solver which may solve the problem + is ``"CRAMER"``. This method uses Cramer's rule to solve the system. This method + is slower and results in more operations than the default solver. However it only + uses a single division by default per entry of the solution. + + While a valid list of solvers can be found at + :meth:`sympy.matrices.matrixbase.MatrixBase.solve`, it is also possible to supply a + `callable`. This way it is possible to use a different solver routine. If the + kinematic differential equations are not too complex it can be worth it to simplify + the solution by using ``lambda A, b: simplify(Matrix.LUsolve(A, b))``. Another + option solver one may use is :func:`sympy.solvers.solveset.linsolve`. This can be + done using `lambda A, b: tuple(linsolve((A, b)))[0]`, where we select the first + solution as our system should have only one unique solution. + + Examples + ======== + + This is a simple example for a one degree of freedom translational + spring-mass-damper. + + In this example, we first need to do the kinematics. + This involves creating generalized speeds and coordinates and their + derivatives. + Then we create a point and set its velocity in a frame. + + >>> from sympy import symbols + >>> from sympy.physics.mechanics import dynamicsymbols, ReferenceFrame + >>> from sympy.physics.mechanics import Point, Particle, KanesMethod + >>> q, u = dynamicsymbols('q u') + >>> qd, ud = dynamicsymbols('q u', 1) + >>> m, c, k = symbols('m c k') + >>> N = ReferenceFrame('N') + >>> P = Point('P') + >>> P.set_vel(N, u * N.x) + + Next we need to arrange/store information in the way that KanesMethod + requires. The kinematic differential equations should be an iterable of + expressions. A list of forces/torques must be constructed, where each entry + in the list is a (Point, Vector) or (ReferenceFrame, Vector) tuple, where + the Vectors represent the Force or Torque. + Next a particle needs to be created, and it needs to have a point and mass + assigned to it. + Finally, a list of all bodies and particles needs to be created. + + >>> kd = [qd - u] + >>> FL = [(P, (-k * q - c * u) * N.x)] + >>> pa = Particle('pa', P, m) + >>> BL = [pa] + + Finally we can generate the equations of motion. + First we create the KanesMethod object and supply an inertial frame, + coordinates, generalized speeds, and the kinematic differential equations. + Additional quantities such as configuration and motion constraints, + dependent coordinates and speeds, and auxiliary speeds are also supplied + here (see the online documentation). + Next we form FR* and FR to complete: Fr + Fr* = 0. + We have the equations of motion at this point. + It makes sense to rearrange them though, so we calculate the mass matrix and + the forcing terms, for E.o.M. in the form: [MM] udot = forcing, where MM is + the mass matrix, udot is a vector of the time derivatives of the + generalized speeds, and forcing is a vector representing "forcing" terms. + + >>> KM = KanesMethod(N, q_ind=[q], u_ind=[u], kd_eqs=kd) + >>> (fr, frstar) = KM.kanes_equations(BL, FL) + >>> MM = KM.mass_matrix + >>> forcing = KM.forcing + >>> rhs = MM.inv() * forcing + >>> rhs + Matrix([[(-c*u(t) - k*q(t))/m]]) + >>> KM.linearize(A_and_B=True)[0] + Matrix([ + [ 0, 1], + [-k/m, -c/m]]) + + Please look at the documentation pages for more information on how to + perform linearization and how to deal with dependent coordinates & speeds, + and how do deal with bringing non-contributing forces into evidence. + + """ + + def __init__(self, frame, q_ind, u_ind, kd_eqs=None, q_dependent=None, + configuration_constraints=None, u_dependent=None, + velocity_constraints=None, acceleration_constraints=None, + u_auxiliary=None, bodies=None, forcelist=None, + explicit_kinematics=True, kd_eqs_solver='LU', + constraint_solver='LU'): + + """Please read the online documentation. """ + if not q_ind: + q_ind = [dynamicsymbols('dummy_q')] + kd_eqs = [dynamicsymbols('dummy_kd')] + + if not isinstance(frame, ReferenceFrame): + raise TypeError('An inertial ReferenceFrame must be supplied') + self._inertial = frame + + self._fr = None + self._frstar = None + + self._forcelist = forcelist + self._bodylist = bodies + + self.explicit_kinematics = explicit_kinematics + self._constraint_solver = constraint_solver + self._initialize_vectors(q_ind, q_dependent, u_ind, u_dependent, + u_auxiliary) + _validate_coordinates(self.q, self.u) + self._initialize_kindiffeq_matrices(kd_eqs, kd_eqs_solver) + self._initialize_constraint_matrices( + configuration_constraints, velocity_constraints, + acceleration_constraints, constraint_solver) + + def _initialize_vectors(self, q_ind, q_dep, u_ind, u_dep, u_aux): + """Initialize the coordinate and speed vectors.""" + + none_handler = lambda x: Matrix(x) if x else Matrix() + + # Initialize generalized coordinates + q_dep = none_handler(q_dep) + if not iterable(q_ind): + raise TypeError('Generalized coordinates must be an iterable.') + if not iterable(q_dep): + raise TypeError('Dependent coordinates must be an iterable.') + q_ind = Matrix(q_ind) + self._qdep = q_dep + self._q = Matrix([q_ind, q_dep]) + self._qdot = self.q.diff(dynamicsymbols._t) + + # Initialize generalized speeds + u_dep = none_handler(u_dep) + if not iterable(u_ind): + raise TypeError('Generalized speeds must be an iterable.') + if not iterable(u_dep): + raise TypeError('Dependent speeds must be an iterable.') + u_ind = Matrix(u_ind) + self._udep = u_dep + self._u = Matrix([u_ind, u_dep]) + self._udot = self.u.diff(dynamicsymbols._t) + self._uaux = none_handler(u_aux) + + def _initialize_constraint_matrices(self, config, vel, acc, linear_solver='LU'): + """Initializes constraint matrices.""" + linear_solver = _parse_linear_solver(linear_solver) + # Define vector dimensions + o = len(self.u) + m = len(self._udep) + p = o - m + none_handler = lambda x: Matrix(x) if x else Matrix() + + # Initialize configuration constraints + config = none_handler(config) + if len(self._qdep) != len(config): + raise ValueError('There must be an equal number of dependent ' + 'coordinates and configuration constraints.') + self._f_h = none_handler(config) + + # Initialize velocity and acceleration constraints + vel = none_handler(vel) + acc = none_handler(acc) + if len(vel) != m: + raise ValueError('There must be an equal number of dependent ' + 'speeds and velocity constraints.') + if acc and (len(acc) != m): + raise ValueError('There must be an equal number of dependent ' + 'speeds and acceleration constraints.') + if vel: + u_zero = dict.fromkeys(self.u, 0) + udot_zero = dict.fromkeys(self._udot, 0) + + # When calling kanes_equations, another class instance will be + # created if auxiliary u's are present. In this case, the + # computation of kinetic differential equation matrices will be + # skipped as this was computed during the original KanesMethod + # object, and the qd_u_map will not be available. + if self._qdot_u_map is not None: + vel = msubs(vel, self._qdot_u_map) + + self._f_nh = msubs(vel, u_zero) + self._k_nh = (vel - self._f_nh).jacobian(self.u) + # If no acceleration constraints given, calculate them. + if not acc: + _f_dnh = (self._k_nh.diff(dynamicsymbols._t) * self.u + + self._f_nh.diff(dynamicsymbols._t)) + if self._qdot_u_map is not None: + _f_dnh = msubs(_f_dnh, self._qdot_u_map) + self._f_dnh = _f_dnh + self._k_dnh = self._k_nh + else: + if self._qdot_u_map is not None: + acc = msubs(acc, self._qdot_u_map) + self._f_dnh = msubs(acc, udot_zero) + self._k_dnh = (acc - self._f_dnh).jacobian(self._udot) + + # Form of non-holonomic constraints is B*u + C = 0. + # We partition B into independent and dependent columns: + # Ars is then -B_dep.inv() * B_ind, and it relates dependent speeds + # to independent speeds as: udep = Ars*uind, neglecting the C term. + B_ind = self._k_nh[:, :p] + B_dep = self._k_nh[:, p:o] + self._Ars = -linear_solver(B_dep, B_ind) + else: + self._f_nh = Matrix() + self._k_nh = Matrix() + self._f_dnh = Matrix() + self._k_dnh = Matrix() + self._Ars = Matrix() + + def _initialize_kindiffeq_matrices(self, kdeqs, linear_solver='LU'): + """Initialize the kinematic differential equation matrices. + + Parameters + ========== + kdeqs : sequence of sympy expressions + Kinematic differential equations in the form of f(u,q',q,t) where + f() = 0. The equations have to be linear in the generalized + coordinates and generalized speeds. + + """ + linear_solver = _parse_linear_solver(linear_solver) + if kdeqs: + if len(self.q) != len(kdeqs): + raise ValueError('There must be an equal number of kinematic ' + 'differential equations and coordinates.') + + u = self.u + qdot = self._qdot + + kdeqs = Matrix(kdeqs) + + u_zero = dict.fromkeys(u, 0) + uaux_zero = dict.fromkeys(self._uaux, 0) + qdot_zero = dict.fromkeys(qdot, 0) + + # Extract the linear coefficient matrices as per the following + # equation: + # + # k_ku(q,t)*u(t) + k_kqdot(q,t)*q'(t) + f_k(q,t) = 0 + # + k_ku = kdeqs.jacobian(u) + k_kqdot = kdeqs.jacobian(qdot) + f_k = kdeqs.xreplace(u_zero).xreplace(qdot_zero) + + # The kinematic differential equations should be linear in both q' + # and u, so check for u and q' in the components. + dy_syms = find_dynamicsymbols(k_ku.row_join(k_kqdot).row_join(f_k)) + nonlin_vars = [vari for vari in u[:] + qdot[:] if vari in dy_syms] + if nonlin_vars: + msg = ('The provided kinematic differential equations are ' + 'nonlinear in {}. They must be linear in the ' + 'generalized speeds and derivatives of the generalized ' + 'coordinates.') + raise ValueError(msg.format(nonlin_vars)) + + self._f_k_implicit = f_k.xreplace(uaux_zero) + self._k_ku_implicit = k_ku.xreplace(uaux_zero) + self._k_kqdot_implicit = k_kqdot + + # Solve for q'(t) such that the coefficient matrices are now in + # this form: + # + # k_kqdot^-1*k_ku*u(t) + I*q'(t) + k_kqdot^-1*f_k = 0 + # + # NOTE : Solving the kinematic differential equations here is not + # necessary and prevents the equations from being provided in fully + # implicit form. + f_k_explicit = linear_solver(k_kqdot, f_k) + k_ku_explicit = linear_solver(k_kqdot, k_ku) + self._qdot_u_map = dict(zip(qdot, -(k_ku_explicit*u + f_k_explicit))) + + self._f_k = f_k_explicit.xreplace(uaux_zero) + self._k_ku = k_ku_explicit.xreplace(uaux_zero) + self._k_kqdot = eye(len(qdot)) + + else: + self._qdot_u_map = None + self._f_k_implicit = self._f_k = Matrix() + self._k_ku_implicit = self._k_ku = Matrix() + self._k_kqdot_implicit = self._k_kqdot = Matrix() + + def _form_fr(self, fl): + """Form the generalized active force.""" + if fl is not None and (len(fl) == 0 or not iterable(fl)): + raise ValueError('Force pairs must be supplied in an ' + 'non-empty iterable or None.') + + N = self._inertial + # pull out relevant velocities for constructing partial velocities + vel_list, f_list = _f_list_parser(fl, N) + vel_list = [msubs(i, self._qdot_u_map) for i in vel_list] + f_list = [msubs(i, self._qdot_u_map) for i in f_list] + + # Fill Fr with dot product of partial velocities and forces + o = len(self.u) + b = len(f_list) + FR = zeros(o, 1) + partials = partial_velocity(vel_list, self.u, N) + for i in range(o): + FR[i] = sum(partials[j][i].dot(f_list[j]) for j in range(b)) + + # In case there are dependent speeds + if self._udep: + p = o - len(self._udep) + FRtilde = FR[:p, 0] + FRold = FR[p:o, 0] + FRtilde += self._Ars.T * FRold + FR = FRtilde + + self._forcelist = fl + self._fr = FR + return FR + + def _form_frstar(self, bl): + """Form the generalized inertia force.""" + + if not iterable(bl): + raise TypeError('Bodies must be supplied in an iterable.') + + t = dynamicsymbols._t + N = self._inertial + # Dicts setting things to zero + udot_zero = dict.fromkeys(self._udot, 0) + uaux_zero = dict.fromkeys(self._uaux, 0) + uauxdot = [diff(i, t) for i in self._uaux] + uauxdot_zero = dict.fromkeys(uauxdot, 0) + # Dictionary of q' and q'' to u and u' + q_ddot_u_map = {k.diff(t): v.diff(t).xreplace( + self._qdot_u_map) for (k, v) in self._qdot_u_map.items()} + q_ddot_u_map.update(self._qdot_u_map) + + # Fill up the list of partials: format is a list with num elements + # equal to number of entries in body list. Each of these elements is a + # list - either of length 1 for the translational components of + # particles or of length 2 for the translational and rotational + # components of rigid bodies. The inner most list is the list of + # partial velocities. + def get_partial_velocity(body): + if isinstance(body, RigidBody): + vlist = [body.masscenter.vel(N), body.frame.ang_vel_in(N)] + elif isinstance(body, Particle): + vlist = [body.point.vel(N),] + else: + raise TypeError('The body list may only contain either ' + 'RigidBody or Particle as list elements.') + v = [msubs(vel, self._qdot_u_map) for vel in vlist] + return partial_velocity(v, self.u, N) + partials = [get_partial_velocity(body) for body in bl] + + # Compute fr_star in two components: + # fr_star = -(MM*u' + nonMM) + o = len(self.u) + MM = zeros(o, o) + nonMM = zeros(o, 1) + zero_uaux = lambda expr: msubs(expr, uaux_zero) + zero_udot_uaux = lambda expr: msubs(msubs(expr, udot_zero), uaux_zero) + for i, body in enumerate(bl): + if isinstance(body, RigidBody): + M = zero_uaux(body.mass) + I = zero_uaux(body.central_inertia) + vel = zero_uaux(body.masscenter.vel(N)) + omega = zero_uaux(body.frame.ang_vel_in(N)) + acc = zero_udot_uaux(body.masscenter.acc(N)) + inertial_force = (M.diff(t) * vel + M * acc) + inertial_torque = zero_uaux((I.dt(body.frame).dot(omega)) + + msubs(I.dot(body.frame.ang_acc_in(N)), udot_zero) + + (omega.cross(I.dot(omega)))) + for j in range(o): + tmp_vel = zero_uaux(partials[i][0][j]) + tmp_ang = zero_uaux(I.dot(partials[i][1][j])) + for k in range(o): + # translational + MM[j, k] += M*tmp_vel.dot(partials[i][0][k]) + # rotational + MM[j, k] += tmp_ang.dot(partials[i][1][k]) + nonMM[j] += inertial_force.dot(partials[i][0][j]) + nonMM[j] += inertial_torque.dot(partials[i][1][j]) + else: + M = zero_uaux(body.mass) + vel = zero_uaux(body.point.vel(N)) + acc = zero_udot_uaux(body.point.acc(N)) + inertial_force = (M.diff(t) * vel + M * acc) + for j in range(o): + temp = zero_uaux(partials[i][0][j]) + for k in range(o): + MM[j, k] += M*temp.dot(partials[i][0][k]) + nonMM[j] += inertial_force.dot(partials[i][0][j]) + # Compose fr_star out of MM and nonMM + MM = zero_uaux(msubs(MM, q_ddot_u_map)) + nonMM = msubs(msubs(nonMM, q_ddot_u_map), + udot_zero, uauxdot_zero, uaux_zero) + fr_star = -(MM * msubs(Matrix(self._udot), uauxdot_zero) + nonMM) + + # If there are dependent speeds, we need to find fr_star_tilde + if self._udep: + p = o - len(self._udep) + fr_star_ind = fr_star[:p, 0] + fr_star_dep = fr_star[p:o, 0] + fr_star = fr_star_ind + (self._Ars.T * fr_star_dep) + # Apply the same to MM + MMi = MM[:p, :] + MMd = MM[p:o, :] + MM = MMi + (self._Ars.T * MMd) + # Apply the same to nonMM + nonMM = nonMM[:p, :] + (self._Ars.T * nonMM[p:o, :]) + + self._bodylist = bl + self._frstar = fr_star + self._k_d = MM + self._f_d = -(self._fr - nonMM) + return fr_star + + def to_linearizer(self, linear_solver='LU'): + """Returns an instance of the Linearizer class, initiated from the + data in the KanesMethod class. This may be more desirable than using + the linearize class method, as the Linearizer object will allow more + efficient recalculation (i.e. about varying operating points). + + Parameters + ========== + linear_solver : str, callable + Method used to solve the several symbolic linear systems of the + form ``A*x=b`` in the linearization process. If a string is + supplied, it should be a valid method that can be used with the + :meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is + supplied, it should have the format ``x = f(A, b)``, where it + solves the equations and returns the solution. The default is + ``'LU'`` which corresponds to SymPy's ``A.LUsolve(b)``. + ``LUsolve()`` is fast to compute but will often result in + divide-by-zero and thus ``nan`` results. + + Returns + ======= + Linearizer + An instantiated + :class:`sympy.physics.mechanics.linearize.Linearizer`. + + """ + + if (self._fr is None) or (self._frstar is None): + raise ValueError('Need to compute Fr, Fr* first.') + + # Get required equation components. The Kane's method class breaks + # these into pieces. Need to reassemble + f_c = self._f_h + if self._f_nh and self._k_nh: + f_v = self._f_nh + self._k_nh*Matrix(self.u) + else: + f_v = Matrix() + if self._f_dnh and self._k_dnh: + f_a = self._f_dnh + self._k_dnh*Matrix(self._udot) + else: + f_a = Matrix() + # Dicts to sub to zero, for splitting up expressions + u_zero = dict.fromkeys(self.u, 0) + ud_zero = dict.fromkeys(self._udot, 0) + qd_zero = dict.fromkeys(self._qdot, 0) + qd_u_zero = dict.fromkeys(Matrix([self._qdot, self.u]), 0) + # Break the kinematic differential eqs apart into f_0 and f_1 + f_0 = msubs(self._f_k, u_zero) + self._k_kqdot*Matrix(self._qdot) + f_1 = msubs(self._f_k, qd_zero) + self._k_ku*Matrix(self.u) + # Break the dynamic differential eqs into f_2 and f_3 + f_2 = msubs(self._frstar, qd_u_zero) + f_3 = msubs(self._frstar, ud_zero) + self._fr + f_4 = zeros(len(f_2), 1) + + # Get the required vector components + q = self.q + u = self.u + if self._qdep: + q_i = q[:-len(self._qdep)] + else: + q_i = q + q_d = self._qdep + if self._udep: + u_i = u[:-len(self._udep)] + else: + u_i = u + u_d = self._udep + + # Form dictionary to set auxiliary speeds & their derivatives to 0. + uaux = self._uaux + uauxdot = uaux.diff(dynamicsymbols._t) + uaux_zero = dict.fromkeys(Matrix([uaux, uauxdot]), 0) + + # Checking for dynamic symbols outside the dynamic differential + # equations; throws error if there is. + sym_list = set(Matrix([q, self._qdot, u, self._udot, uaux, uauxdot])) + if any(find_dynamicsymbols(i, sym_list) for i in [self._k_kqdot, + self._k_ku, self._f_k, self._k_dnh, self._f_dnh, self._k_d]): + raise ValueError('Cannot have dynamicsymbols outside dynamic \ + forcing vector.') + + # Find all other dynamic symbols, forming the forcing vector r. + # Sort r to make it canonical. + r = list(find_dynamicsymbols(msubs(self._f_d, uaux_zero), sym_list)) + r.sort(key=default_sort_key) + + # Check for any derivatives of variables in r that are also found in r. + for i in r: + if diff(i, dynamicsymbols._t) in r: + raise ValueError('Cannot have derivatives of specified \ + quantities when linearizing forcing terms.') + return Linearizer(f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a, q, u, q_i, + q_d, u_i, u_d, r, linear_solver=linear_solver) + + # TODO : Remove `new_method` after 1.1 has been released. + def linearize(self, *, new_method=None, linear_solver='LU', **kwargs): + """ Linearize the equations of motion about a symbolic operating point. + + Parameters + ========== + new_method + Deprecated, does nothing and will be removed. + linear_solver : str, callable + Method used to solve the several symbolic linear systems of the + form ``A*x=b`` in the linearization process. If a string is + supplied, it should be a valid method that can be used with the + :meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is + supplied, it should have the format ``x = f(A, b)``, where it + solves the equations and returns the solution. The default is + ``'LU'`` which corresponds to SymPy's ``A.LUsolve(b)``. + ``LUsolve()`` is fast to compute but will often result in + divide-by-zero and thus ``nan`` results. + **kwargs + Extra keyword arguments are passed to + :meth:`sympy.physics.mechanics.linearize.Linearizer.linearize`. + + Explanation + =========== + + If kwarg A_and_B is False (default), returns M, A, B, r for the + linearized form, M*[q', u']^T = A*[q_ind, u_ind]^T + B*r. + + If kwarg A_and_B is True, returns A, B, r for the linearized form + dx = A*x + B*r, where x = [q_ind, u_ind]^T. Note that this is + computationally intensive if there are many symbolic parameters. For + this reason, it may be more desirable to use the default A_and_B=False, + returning M, A, and B. Values may then be substituted in to these + matrices, and the state space form found as + A = P.T*M.inv()*A, B = P.T*M.inv()*B, where P = Linearizer.perm_mat. + + In both cases, r is found as all dynamicsymbols in the equations of + motion that are not part of q, u, q', or u'. They are sorted in + canonical form. + + The operating points may be also entered using the ``op_point`` kwarg. + This takes a dictionary of {symbol: value}, or a an iterable of such + dictionaries. The values may be numeric or symbolic. The more values + you can specify beforehand, the faster this computation will run. + + For more documentation, please see the ``Linearizer`` class. + + """ + + linearizer = self.to_linearizer(linear_solver=linear_solver) + result = linearizer.linearize(**kwargs) + return result + (linearizer.r,) + + def kanes_equations(self, bodies=None, loads=None): + """ Method to form Kane's equations, Fr + Fr* = 0. + + Explanation + =========== + + Returns (Fr, Fr*). In the case where auxiliary generalized speeds are + present (say, s auxiliary speeds, o generalized speeds, and m motion + constraints) the length of the returned vectors will be o - m + s in + length. The first o - m equations will be the constrained Kane's + equations, then the s auxiliary Kane's equations. These auxiliary + equations can be accessed with the auxiliary_eqs property. + + Parameters + ========== + + bodies : iterable + An iterable of all RigidBody's and Particle's in the system. + A system must have at least one body. + loads : iterable + Takes in an iterable of (Particle, Vector) or (ReferenceFrame, Vector) + tuples which represent the force at a point or torque on a frame. + Must be either a non-empty iterable of tuples or None which corresponds + to a system with no constraints. + """ + if bodies is None: + bodies = self.bodies + if loads is None and self._forcelist is not None: + loads = self._forcelist + if loads == []: + loads = None + if not self._k_kqdot: + raise AttributeError('Create an instance of KanesMethod with ' + 'kinematic differential equations to use this method.') + fr = self._form_fr(loads) + frstar = self._form_frstar(bodies) + if self._uaux: + if not self._udep: + km = KanesMethod(self._inertial, self.q, self._uaux, + u_auxiliary=self._uaux, constraint_solver=self._constraint_solver) + else: + km = KanesMethod(self._inertial, self.q, self._uaux, + u_auxiliary=self._uaux, u_dependent=self._udep, + velocity_constraints=(self._k_nh * self.u + + self._f_nh), + acceleration_constraints=(self._k_dnh * self._udot + + self._f_dnh), + constraint_solver=self._constraint_solver + ) + km._qdot_u_map = self._qdot_u_map + self._km = km + fraux = km._form_fr(loads) + frstaraux = km._form_frstar(bodies) + self._aux_eq = fraux + frstaraux + self._fr = fr.col_join(fraux) + self._frstar = frstar.col_join(frstaraux) + return (self._fr, self._frstar) + + def _form_eoms(self): + fr, frstar = self.kanes_equations(self.bodylist, self.forcelist) + return fr + frstar + + def rhs(self, inv_method=None): + """Returns the system's equations of motion in first order form. The + output is the right hand side of:: + + x' = |q'| =: f(q, u, r, p, t) + |u'| + + The right hand side is what is needed by most numerical ODE + integrators. + + Parameters + ========== + + inv_method : str + The specific sympy inverse matrix calculation method to use. For a + list of valid methods, see + :meth:`~sympy.matrices.matrixbase.MatrixBase.inv` + + """ + rhs = zeros(len(self.q) + len(self.u), 1) + kdes = self.kindiffdict() + for i, q_i in enumerate(self.q): + rhs[i] = kdes[q_i.diff()] + + if inv_method is None: + rhs[len(self.q):, 0] = self.mass_matrix.LUsolve(self.forcing) + else: + rhs[len(self.q):, 0] = (self.mass_matrix.inv(inv_method, + try_block_diag=True) * + self.forcing) + + return rhs + + def kindiffdict(self): + """Returns a dictionary mapping q' to u.""" + if not self._qdot_u_map: + raise AttributeError('Create an instance of KanesMethod with ' + 'kinematic differential equations to use this method.') + return self._qdot_u_map + + @property + def auxiliary_eqs(self): + """A matrix containing the auxiliary equations.""" + if not self._fr or not self._frstar: + raise ValueError('Need to compute Fr, Fr* first.') + if not self._uaux: + raise ValueError('No auxiliary speeds have been declared.') + return self._aux_eq + + @property + def mass_matrix_kin(self): + r"""The kinematic "mass matrix" $\mathbf{k_{k\dot{q}}}$ of the system.""" + return self._k_kqdot if self.explicit_kinematics else self._k_kqdot_implicit + + @property + def forcing_kin(self): + """The kinematic "forcing vector" of the system.""" + if self.explicit_kinematics: + return -(self._k_ku * Matrix(self.u) + self._f_k) + else: + return -(self._k_ku_implicit * Matrix(self.u) + self._f_k_implicit) + + @property + def mass_matrix(self): + """The mass matrix of the system.""" + if not self._fr or not self._frstar: + raise ValueError('Need to compute Fr, Fr* first.') + return Matrix([self._k_d, self._k_dnh]) + + @property + def forcing(self): + """The forcing vector of the system.""" + if not self._fr or not self._frstar: + raise ValueError('Need to compute Fr, Fr* first.') + return -Matrix([self._f_d, self._f_dnh]) + + @property + def mass_matrix_full(self): + """The mass matrix of the system, augmented by the kinematic + differential equations in explicit or implicit form.""" + if not self._fr or not self._frstar: + raise ValueError('Need to compute Fr, Fr* first.') + o, n = len(self.u), len(self.q) + return (self.mass_matrix_kin.row_join(zeros(n, o))).col_join( + zeros(o, n).row_join(self.mass_matrix)) + + @property + def forcing_full(self): + """The forcing vector of the system, augmented by the kinematic + differential equations in explicit or implicit form.""" + return Matrix([self.forcing_kin, self.forcing]) + + @property + def q(self): + return self._q + + @property + def u(self): + return self._u + + @property + def bodylist(self): + return self._bodylist + + @property + def forcelist(self): + return self._forcelist + + @property + def bodies(self): + return self._bodylist + + @property + def loads(self): + return self._forcelist diff --git a/lib/python3.12/site-packages/sympy/physics/mechanics/linearize.py b/lib/python3.12/site-packages/sympy/physics/mechanics/linearize.py new file mode 100644 index 0000000000000000000000000000000000000000..9d102c61f8f60318f1a2c9896e94324c8cf02889 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/mechanics/linearize.py @@ -0,0 +1,474 @@ +__all__ = ['Linearizer'] + +from sympy import Matrix, eye, zeros +from sympy.core.symbol import Dummy +from sympy.utilities.iterables import flatten +from sympy.physics.vector import dynamicsymbols +from sympy.physics.mechanics.functions import msubs, _parse_linear_solver + +from collections import namedtuple +from collections.abc import Iterable + + +class Linearizer: + """This object holds the general model form for a dynamic system. This + model is used for computing the linearized form of the system, while + properly dealing with constraints leading to dependent coordinates and + speeds. The notation and method is described in [1]_. + + Attributes + ========== + + f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a : Matrix + Matrices holding the general system form. + q, u, r : Matrix + Matrices holding the generalized coordinates, speeds, and + input vectors. + q_i, u_i : Matrix + Matrices of the independent generalized coordinates and speeds. + q_d, u_d : Matrix + Matrices of the dependent generalized coordinates and speeds. + perm_mat : Matrix + Permutation matrix such that [q_ind, u_ind]^T = perm_mat*[q, u]^T + + References + ========== + + .. [1] D. L. Peterson, G. Gede, and M. Hubbard, "Symbolic linearization of + equations of motion of constrained multibody systems," Multibody + Syst Dyn, vol. 33, no. 2, pp. 143-161, Feb. 2015, doi: + 10.1007/s11044-014-9436-5. + + """ + + def __init__(self, f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a, q, u, q_i=None, + q_d=None, u_i=None, u_d=None, r=None, lams=None, + linear_solver='LU'): + """ + Parameters + ========== + + f_0, f_1, f_2, f_3, f_4, f_c, f_v, f_a : array_like + System of equations holding the general system form. + Supply empty array or Matrix if the parameter + does not exist. + q : array_like + The generalized coordinates. + u : array_like + The generalized speeds + q_i, u_i : array_like, optional + The independent generalized coordinates and speeds. + q_d, u_d : array_like, optional + The dependent generalized coordinates and speeds. + r : array_like, optional + The input variables. + lams : array_like, optional + The lagrange multipliers + linear_solver : str, callable + Method used to solve the several symbolic linear systems of the + form ``A*x=b`` in the linearization process. If a string is + supplied, it should be a valid method that can be used with the + :meth:`sympy.matrices.matrixbase.MatrixBase.solve`. If a callable is + supplied, it should have the format ``x = f(A, b)``, where it + solves the equations and returns the solution. The default is + ``'LU'`` which corresponds to SymPy's ``A.LUsolve(b)``. + ``LUsolve()`` is fast to compute but will often result in + divide-by-zero and thus ``nan`` results. + + """ + self.linear_solver = _parse_linear_solver(linear_solver) + + # Generalized equation form + self.f_0 = Matrix(f_0) + self.f_1 = Matrix(f_1) + self.f_2 = Matrix(f_2) + self.f_3 = Matrix(f_3) + self.f_4 = Matrix(f_4) + self.f_c = Matrix(f_c) + self.f_v = Matrix(f_v) + self.f_a = Matrix(f_a) + + # Generalized equation variables + self.q = Matrix(q) + self.u = Matrix(u) + none_handler = lambda x: Matrix(x) if x else Matrix() + self.q_i = none_handler(q_i) + self.q_d = none_handler(q_d) + self.u_i = none_handler(u_i) + self.u_d = none_handler(u_d) + self.r = none_handler(r) + self.lams = none_handler(lams) + + # Derivatives of generalized equation variables + self._qd = self.q.diff(dynamicsymbols._t) + self._ud = self.u.diff(dynamicsymbols._t) + # If the user doesn't actually use generalized variables, and the + # qd and u vectors have any intersecting variables, this can cause + # problems. We'll fix this with some hackery, and Dummy variables + dup_vars = set(self._qd).intersection(self.u) + self._qd_dup = Matrix([var if var not in dup_vars else Dummy() for var + in self._qd]) + + # Derive dimesion terms + l = len(self.f_c) + m = len(self.f_v) + n = len(self.q) + o = len(self.u) + s = len(self.r) + k = len(self.lams) + dims = namedtuple('dims', ['l', 'm', 'n', 'o', 's', 'k']) + self._dims = dims(l, m, n, o, s, k) + + self._Pq = None + self._Pqi = None + self._Pqd = None + self._Pu = None + self._Pui = None + self._Pud = None + self._C_0 = None + self._C_1 = None + self._C_2 = None + self.perm_mat = None + + self._setup_done = False + + def _setup(self): + # Calculations here only need to be run once. They are moved out of + # the __init__ method to increase the speed of Linearizer creation. + self._form_permutation_matrices() + self._form_block_matrices() + self._form_coefficient_matrices() + self._setup_done = True + + def _form_permutation_matrices(self): + """Form the permutation matrices Pq and Pu.""" + + # Extract dimension variables + l, m, n, o, s, k = self._dims + # Compute permutation matrices + if n != 0: + self._Pq = permutation_matrix(self.q, Matrix([self.q_i, self.q_d])) + if l > 0: + self._Pqi = self._Pq[:, :-l] + self._Pqd = self._Pq[:, -l:] + else: + self._Pqi = self._Pq + self._Pqd = Matrix() + if o != 0: + self._Pu = permutation_matrix(self.u, Matrix([self.u_i, self.u_d])) + if m > 0: + self._Pui = self._Pu[:, :-m] + self._Pud = self._Pu[:, -m:] + else: + self._Pui = self._Pu + self._Pud = Matrix() + # Compute combination permutation matrix for computing A and B + P_col1 = Matrix([self._Pqi, zeros(o + k, n - l)]) + P_col2 = Matrix([zeros(n, o - m), self._Pui, zeros(k, o - m)]) + if P_col1: + if P_col2: + self.perm_mat = P_col1.row_join(P_col2) + else: + self.perm_mat = P_col1 + else: + self.perm_mat = P_col2 + + def _form_coefficient_matrices(self): + """Form the coefficient matrices C_0, C_1, and C_2.""" + + # Extract dimension variables + l, m, n, o, s, k = self._dims + # Build up the coefficient matrices C_0, C_1, and C_2 + # If there are configuration constraints (l > 0), form C_0 as normal. + # If not, C_0 is I_(nxn). Note that this works even if n=0 + if l > 0: + f_c_jac_q = self.f_c.jacobian(self.q) + self._C_0 = (eye(n) - self._Pqd * + self.linear_solver(f_c_jac_q*self._Pqd, + f_c_jac_q))*self._Pqi + else: + self._C_0 = eye(n) + # If there are motion constraints (m > 0), form C_1 and C_2 as normal. + # If not, C_1 is 0, and C_2 is I_(oxo). Note that this works even if + # o = 0. + if m > 0: + f_v_jac_u = self.f_v.jacobian(self.u) + temp = f_v_jac_u * self._Pud + if n != 0: + f_v_jac_q = self.f_v.jacobian(self.q) + self._C_1 = -self._Pud * self.linear_solver(temp, f_v_jac_q) + else: + self._C_1 = zeros(o, n) + self._C_2 = (eye(o) - self._Pud * + self.linear_solver(temp, f_v_jac_u))*self._Pui + else: + self._C_1 = zeros(o, n) + self._C_2 = eye(o) + + def _form_block_matrices(self): + """Form the block matrices for composing M, A, and B.""" + + # Extract dimension variables + l, m, n, o, s, k = self._dims + # Block Matrix Definitions. These are only defined if under certain + # conditions. If undefined, an empty matrix is used instead + if n != 0: + self._M_qq = self.f_0.jacobian(self._qd) + self._A_qq = -(self.f_0 + self.f_1).jacobian(self.q) + else: + self._M_qq = Matrix() + self._A_qq = Matrix() + if n != 0 and m != 0: + self._M_uqc = self.f_a.jacobian(self._qd_dup) + self._A_uqc = -self.f_a.jacobian(self.q) + else: + self._M_uqc = Matrix() + self._A_uqc = Matrix() + if n != 0 and o - m + k != 0: + self._M_uqd = self.f_3.jacobian(self._qd_dup) + self._A_uqd = -(self.f_2 + self.f_3 + self.f_4).jacobian(self.q) + else: + self._M_uqd = Matrix() + self._A_uqd = Matrix() + if o != 0 and m != 0: + self._M_uuc = self.f_a.jacobian(self._ud) + self._A_uuc = -self.f_a.jacobian(self.u) + else: + self._M_uuc = Matrix() + self._A_uuc = Matrix() + if o != 0 and o - m + k != 0: + self._M_uud = self.f_2.jacobian(self._ud) + self._A_uud = -(self.f_2 + self.f_3).jacobian(self.u) + else: + self._M_uud = Matrix() + self._A_uud = Matrix() + if o != 0 and n != 0: + self._A_qu = -self.f_1.jacobian(self.u) + else: + self._A_qu = Matrix() + if k != 0 and o - m + k != 0: + self._M_uld = self.f_4.jacobian(self.lams) + else: + self._M_uld = Matrix() + if s != 0 and o - m + k != 0: + self._B_u = -self.f_3.jacobian(self.r) + else: + self._B_u = Matrix() + + def linearize(self, op_point=None, A_and_B=False, simplify=False): + """Linearize the system about the operating point. Note that + q_op, u_op, qd_op, ud_op must satisfy the equations of motion. + These may be either symbolic or numeric. + + Parameters + ========== + op_point : dict or iterable of dicts, optional + Dictionary or iterable of dictionaries containing the operating + point conditions for all or a subset of the generalized + coordinates, generalized speeds, and time derivatives of the + generalized speeds. These will be substituted into the linearized + system before the linearization is complete. Leave set to ``None`` + if you want the operating point to be an arbitrary set of symbols. + Note that any reduction in symbols (whether substituted for numbers + or expressions with a common parameter) will result in faster + runtime. + A_and_B : bool, optional + If A_and_B=False (default), (M, A, B) is returned and of + A_and_B=True, (A, B) is returned. See below. + simplify : bool, optional + Determines if returned values are simplified before return. + For large expressions this may be time consuming. Default is False. + + Returns + ======= + M, A, B : Matrices, ``A_and_B=False`` + Matrices from the implicit form: + ``[M]*[q', u']^T = [A]*[q_ind, u_ind]^T + [B]*r`` + A, B : Matrices, ``A_and_B=True`` + Matrices from the explicit form: + ``[q_ind', u_ind']^T = [A]*[q_ind, u_ind]^T + [B]*r`` + + Notes + ===== + + Note that the process of solving with A_and_B=True is computationally + intensive if there are many symbolic parameters. For this reason, it + may be more desirable to use the default A_and_B=False, returning M, A, + and B. More values may then be substituted in to these matrices later + on. The state space form can then be found as A = P.T*M.LUsolve(A), B = + P.T*M.LUsolve(B), where P = Linearizer.perm_mat. + + """ + + # Run the setup if needed: + if not self._setup_done: + self._setup() + + # Compose dict of operating conditions + if isinstance(op_point, dict): + op_point_dict = op_point + elif isinstance(op_point, Iterable): + op_point_dict = {} + for op in op_point: + op_point_dict.update(op) + else: + op_point_dict = {} + + # Extract dimension variables + l, m, n, o, s, k = self._dims + + # Rename terms to shorten expressions + M_qq = self._M_qq + M_uqc = self._M_uqc + M_uqd = self._M_uqd + M_uuc = self._M_uuc + M_uud = self._M_uud + M_uld = self._M_uld + A_qq = self._A_qq + A_uqc = self._A_uqc + A_uqd = self._A_uqd + A_qu = self._A_qu + A_uuc = self._A_uuc + A_uud = self._A_uud + B_u = self._B_u + C_0 = self._C_0 + C_1 = self._C_1 + C_2 = self._C_2 + + # Build up Mass Matrix + # |M_qq 0_nxo 0_nxk| + # M = |M_uqc M_uuc 0_mxk| + # |M_uqd M_uud M_uld| + if o != 0: + col2 = Matrix([zeros(n, o), M_uuc, M_uud]) + if k != 0: + col3 = Matrix([zeros(n + m, k), M_uld]) + if n != 0: + col1 = Matrix([M_qq, M_uqc, M_uqd]) + if o != 0 and k != 0: + M = col1.row_join(col2).row_join(col3) + elif o != 0: + M = col1.row_join(col2) + else: + M = col1 + elif k != 0: + M = col2.row_join(col3) + else: + M = col2 + M_eq = msubs(M, op_point_dict) + + # Build up state coefficient matrix A + # |(A_qq + A_qu*C_1)*C_0 A_qu*C_2| + # A = |(A_uqc + A_uuc*C_1)*C_0 A_uuc*C_2| + # |(A_uqd + A_uud*C_1)*C_0 A_uud*C_2| + # Col 1 is only defined if n != 0 + if n != 0: + r1c1 = A_qq + if o != 0: + r1c1 += (A_qu * C_1) + r1c1 = r1c1 * C_0 + if m != 0: + r2c1 = A_uqc + if o != 0: + r2c1 += (A_uuc * C_1) + r2c1 = r2c1 * C_0 + else: + r2c1 = Matrix() + if o - m + k != 0: + r3c1 = A_uqd + if o != 0: + r3c1 += (A_uud * C_1) + r3c1 = r3c1 * C_0 + else: + r3c1 = Matrix() + col1 = Matrix([r1c1, r2c1, r3c1]) + else: + col1 = Matrix() + # Col 2 is only defined if o != 0 + if o != 0: + if n != 0: + r1c2 = A_qu * C_2 + else: + r1c2 = Matrix() + if m != 0: + r2c2 = A_uuc * C_2 + else: + r2c2 = Matrix() + if o - m + k != 0: + r3c2 = A_uud * C_2 + else: + r3c2 = Matrix() + col2 = Matrix([r1c2, r2c2, r3c2]) + else: + col2 = Matrix() + if col1: + if col2: + Amat = col1.row_join(col2) + else: + Amat = col1 + else: + Amat = col2 + Amat_eq = msubs(Amat, op_point_dict) + + # Build up the B matrix if there are forcing variables + # |0_(n + m)xs| + # B = |B_u | + if s != 0 and o - m + k != 0: + Bmat = zeros(n + m, s).col_join(B_u) + Bmat_eq = msubs(Bmat, op_point_dict) + else: + Bmat_eq = Matrix() + + # kwarg A_and_B indicates to return A, B for forming the equation + # dx = [A]x + [B]r, where x = [q_indnd, u_indnd]^T, + if A_and_B: + A_cont = self.perm_mat.T * self.linear_solver(M_eq, Amat_eq) + if Bmat_eq: + B_cont = self.perm_mat.T * self.linear_solver(M_eq, Bmat_eq) + else: + # Bmat = Matrix([]), so no need to sub + B_cont = Bmat_eq + if simplify: + A_cont.simplify() + B_cont.simplify() + return A_cont, B_cont + # Otherwise return M, A, B for forming the equation + # [M]dx = [A]x + [B]r, where x = [q, u]^T + else: + if simplify: + M_eq.simplify() + Amat_eq.simplify() + Bmat_eq.simplify() + return M_eq, Amat_eq, Bmat_eq + + +def permutation_matrix(orig_vec, per_vec): + """Compute the permutation matrix to change order of + orig_vec into order of per_vec. + + Parameters + ========== + + orig_vec : array_like + Symbols in original ordering. + per_vec : array_like + Symbols in new ordering. + + Returns + ======= + + p_matrix : Matrix + Permutation matrix such that orig_vec == (p_matrix * per_vec). + """ + if not isinstance(orig_vec, (list, tuple)): + orig_vec = flatten(orig_vec) + if not isinstance(per_vec, (list, tuple)): + per_vec = flatten(per_vec) + if set(orig_vec) != set(per_vec): + raise ValueError("orig_vec and per_vec must be the same length, " + "and contain the same symbols.") + ind_list = [orig_vec.index(i) for i in per_vec] + p_matrix = zeros(len(orig_vec)) + for i, j in enumerate(ind_list): + p_matrix[i, j] = 1 + return p_matrix diff --git a/lib/python3.12/site-packages/sympy/physics/mechanics/models.py b/lib/python3.12/site-packages/sympy/physics/mechanics/models.py new file mode 100644 index 0000000000000000000000000000000000000000..a89b929ffd540a07787f6f94714850b348c90781 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/mechanics/models.py @@ -0,0 +1,230 @@ +#!/usr/bin/env python +"""This module contains some sample symbolic models used for testing and +examples.""" + +# Internal imports +from sympy.core import backend as sm +import sympy.physics.mechanics as me + + +def multi_mass_spring_damper(n=1, apply_gravity=False, + apply_external_forces=False): + r"""Returns a system containing the symbolic equations of motion and + associated variables for a simple multi-degree of freedom point mass, + spring, damper system with optional gravitational and external + specified forces. For example, a two mass system under the influence of + gravity and external forces looks like: + + :: + + ---------------- + | | | | g + \ | | | V + k0 / --- c0 | + | | | x0, v0 + --------- V + | m0 | ----- + --------- | + | | | | + \ v | | | + k1 / f0 --- c1 | + | | | x1, v1 + --------- V + | m1 | ----- + --------- + | f1 + V + + Parameters + ========== + + n : integer + The number of masses in the serial chain. + apply_gravity : boolean + If true, gravity will be applied to each mass. + apply_external_forces : boolean + If true, a time varying external force will be applied to each mass. + + Returns + ======= + + kane : sympy.physics.mechanics.kane.KanesMethod + A KanesMethod object. + + """ + + mass = sm.symbols('m:{}'.format(n)) + stiffness = sm.symbols('k:{}'.format(n)) + damping = sm.symbols('c:{}'.format(n)) + + acceleration_due_to_gravity = sm.symbols('g') + + coordinates = me.dynamicsymbols('x:{}'.format(n)) + speeds = me.dynamicsymbols('v:{}'.format(n)) + specifieds = me.dynamicsymbols('f:{}'.format(n)) + + ceiling = me.ReferenceFrame('N') + origin = me.Point('origin') + origin.set_vel(ceiling, 0) + + points = [origin] + kinematic_equations = [] + particles = [] + forces = [] + + for i in range(n): + + center = points[-1].locatenew('center{}'.format(i), + coordinates[i] * ceiling.x) + center.set_vel(ceiling, points[-1].vel(ceiling) + + speeds[i] * ceiling.x) + points.append(center) + + block = me.Particle('block{}'.format(i), center, mass[i]) + + kinematic_equations.append(speeds[i] - coordinates[i].diff()) + + total_force = (-stiffness[i] * coordinates[i] - + damping[i] * speeds[i]) + try: + total_force += (stiffness[i + 1] * coordinates[i + 1] + + damping[i + 1] * speeds[i + 1]) + except IndexError: # no force from below on last mass + pass + + if apply_gravity: + total_force += mass[i] * acceleration_due_to_gravity + + if apply_external_forces: + total_force += specifieds[i] + + forces.append((center, total_force * ceiling.x)) + + particles.append(block) + + kane = me.KanesMethod(ceiling, q_ind=coordinates, u_ind=speeds, + kd_eqs=kinematic_equations) + kane.kanes_equations(particles, forces) + + return kane + + +def n_link_pendulum_on_cart(n=1, cart_force=True, joint_torques=False): + r"""Returns the system containing the symbolic first order equations of + motion for a 2D n-link pendulum on a sliding cart under the influence of + gravity. + + :: + + | + o y v + \ 0 ^ g + \ | + --\-|---- + | \| | + F-> | o --|---> x + | | + --------- + o o + + Parameters + ========== + + n : integer + The number of links in the pendulum. + cart_force : boolean, default=True + If true an external specified lateral force is applied to the cart. + joint_torques : boolean, default=False + If true joint torques will be added as specified inputs at each + joint. + + Returns + ======= + + kane : sympy.physics.mechanics.kane.KanesMethod + A KanesMethod object. + + Notes + ===== + + The degrees of freedom of the system are n + 1, i.e. one for each + pendulum link and one for the lateral motion of the cart. + + M x' = F, where x = [u0, ..., un+1, q0, ..., qn+1] + + The joint angles are all defined relative to the ground where the x axis + defines the ground line and the y axis points up. The joint torques are + applied between each adjacent link and the between the cart and the + lower link where a positive torque corresponds to positive angle. + + """ + if n <= 0: + raise ValueError('The number of links must be a positive integer.') + + q = me.dynamicsymbols('q:{}'.format(n + 1)) + u = me.dynamicsymbols('u:{}'.format(n + 1)) + + if joint_torques is True: + T = me.dynamicsymbols('T1:{}'.format(n + 1)) + + m = sm.symbols('m:{}'.format(n + 1)) + l = sm.symbols('l:{}'.format(n)) + g, t = sm.symbols('g t') + + I = me.ReferenceFrame('I') + O = me.Point('O') + O.set_vel(I, 0) + + P0 = me.Point('P0') + P0.set_pos(O, q[0] * I.x) + P0.set_vel(I, u[0] * I.x) + Pa0 = me.Particle('Pa0', P0, m[0]) + + frames = [I] + points = [P0] + particles = [Pa0] + forces = [(P0, -m[0] * g * I.y)] + kindiffs = [q[0].diff(t) - u[0]] + + if cart_force is True or joint_torques is True: + specified = [] + else: + specified = None + + for i in range(n): + Bi = I.orientnew('B{}'.format(i), 'Axis', [q[i + 1], I.z]) + Bi.set_ang_vel(I, u[i + 1] * I.z) + frames.append(Bi) + + Pi = points[-1].locatenew('P{}'.format(i + 1), l[i] * Bi.y) + Pi.v2pt_theory(points[-1], I, Bi) + points.append(Pi) + + Pai = me.Particle('Pa' + str(i + 1), Pi, m[i + 1]) + particles.append(Pai) + + forces.append((Pi, -m[i + 1] * g * I.y)) + + if joint_torques is True: + + specified.append(T[i]) + + if i == 0: + forces.append((I, -T[i] * I.z)) + + if i == n - 1: + forces.append((Bi, T[i] * I.z)) + else: + forces.append((Bi, T[i] * I.z - T[i + 1] * I.z)) + + kindiffs.append(q[i + 1].diff(t) - u[i + 1]) + + if cart_force is True: + F = me.dynamicsymbols('F') + forces.append((P0, F * I.x)) + specified.append(F) + + kane = me.KanesMethod(I, q_ind=q, u_ind=u, kd_eqs=kindiffs) + kane.kanes_equations(particles, forces) + + return kane diff --git a/lib/python3.12/site-packages/sympy/physics/mechanics/particle.py b/lib/python3.12/site-packages/sympy/physics/mechanics/particle.py new file mode 100644 index 0000000000000000000000000000000000000000..5d49d4f811b8d1c7fff16c71991f5e01da6ded02 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/mechanics/particle.py @@ -0,0 +1,209 @@ +from sympy import S +from sympy.physics.vector import cross, dot +from sympy.physics.mechanics.body_base import BodyBase +from sympy.physics.mechanics.inertia import inertia_of_point_mass +from sympy.utilities.exceptions import sympy_deprecation_warning + +__all__ = ['Particle'] + + +class Particle(BodyBase): + """A particle. + + Explanation + =========== + + Particles have a non-zero mass and lack spatial extension; they take up no + space. + + Values need to be supplied on initialization, but can be changed later. + + Parameters + ========== + + name : str + Name of particle + point : Point + A physics/mechanics Point which represents the position, velocity, and + acceleration of this Particle + mass : Sympifyable + A SymPy expression representing the Particle's mass + potential_energy : Sympifyable + The potential energy of the Particle. + + Examples + ======== + + >>> from sympy.physics.mechanics import Particle, Point + >>> from sympy import Symbol + >>> po = Point('po') + >>> m = Symbol('m') + >>> pa = Particle('pa', po, m) + >>> # Or you could change these later + >>> pa.mass = m + >>> pa.point = po + + """ + point = BodyBase.masscenter + + def __init__(self, name, point=None, mass=None): + super().__init__(name, point, mass) + + def linear_momentum(self, frame): + """Linear momentum of the particle. + + Explanation + =========== + + The linear momentum L, of a particle P, with respect to frame N is + given by: + + L = m * v + + where m is the mass of the particle, and v is the velocity of the + particle in the frame N. + + Parameters + ========== + + frame : ReferenceFrame + The frame in which linear momentum is desired. + + Examples + ======== + + >>> from sympy.physics.mechanics import Particle, Point, ReferenceFrame + >>> from sympy.physics.mechanics import dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> m, v = dynamicsymbols('m v') + >>> N = ReferenceFrame('N') + >>> P = Point('P') + >>> A = Particle('A', P, m) + >>> P.set_vel(N, v * N.x) + >>> A.linear_momentum(N) + m*v*N.x + + """ + + return self.mass * self.point.vel(frame) + + def angular_momentum(self, point, frame): + """Angular momentum of the particle about the point. + + Explanation + =========== + + The angular momentum H, about some point O of a particle, P, is given + by: + + ``H = cross(r, m * v)`` + + where r is the position vector from point O to the particle P, m is + the mass of the particle, and v is the velocity of the particle in + the inertial frame, N. + + Parameters + ========== + + point : Point + The point about which angular momentum of the particle is desired. + + frame : ReferenceFrame + The frame in which angular momentum is desired. + + Examples + ======== + + >>> from sympy.physics.mechanics import Particle, Point, ReferenceFrame + >>> from sympy.physics.mechanics import dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> m, v, r = dynamicsymbols('m v r') + >>> N = ReferenceFrame('N') + >>> O = Point('O') + >>> A = O.locatenew('A', r * N.x) + >>> P = Particle('P', A, m) + >>> P.point.set_vel(N, v * N.y) + >>> P.angular_momentum(O, N) + m*r*v*N.z + + """ + + return cross(self.point.pos_from(point), + self.mass * self.point.vel(frame)) + + def kinetic_energy(self, frame): + """Kinetic energy of the particle. + + Explanation + =========== + + The kinetic energy, T, of a particle, P, is given by: + + ``T = 1/2 (dot(m * v, v))`` + + where m is the mass of particle P, and v is the velocity of the + particle in the supplied ReferenceFrame. + + Parameters + ========== + + frame : ReferenceFrame + The Particle's velocity is typically defined with respect to + an inertial frame but any relevant frame in which the velocity is + known can be supplied. + + Examples + ======== + + >>> from sympy.physics.mechanics import Particle, Point, ReferenceFrame + >>> from sympy import symbols + >>> m, v, r = symbols('m v r') + >>> N = ReferenceFrame('N') + >>> O = Point('O') + >>> P = Particle('P', O, m) + >>> P.point.set_vel(N, v * N.y) + >>> P.kinetic_energy(N) + m*v**2/2 + + """ + + return S.Half * self.mass * dot(self.point.vel(frame), + self.point.vel(frame)) + + def set_potential_energy(self, scalar): + sympy_deprecation_warning( + """ +The sympy.physics.mechanics.Particle.set_potential_energy() +method is deprecated. Instead use + + P.potential_energy = scalar + """, + deprecated_since_version="1.5", + active_deprecations_target="deprecated-set-potential-energy", + ) + self.potential_energy = scalar + + def parallel_axis(self, point, frame): + """Returns an inertia dyadic of the particle with respect to another + point and frame. + + Parameters + ========== + + point : sympy.physics.vector.Point + The point to express the inertia dyadic about. + frame : sympy.physics.vector.ReferenceFrame + The reference frame used to construct the dyadic. + + Returns + ======= + + inertia : sympy.physics.vector.Dyadic + The inertia dyadic of the particle expressed about the provided + point and frame. + + """ + return inertia_of_point_mass(self.mass, self.point.pos_from(point), + frame) diff --git a/lib/python3.12/site-packages/sympy/physics/mechanics/rigidbody.py b/lib/python3.12/site-packages/sympy/physics/mechanics/rigidbody.py new file mode 100644 index 0000000000000000000000000000000000000000..7cc61ff468f7f26d98209a48ca59ffa12a570490 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/mechanics/rigidbody.py @@ -0,0 +1,314 @@ +from sympy import Symbol, S +from sympy.physics.vector import ReferenceFrame, Dyadic, Point, dot +from sympy.physics.mechanics.body_base import BodyBase +from sympy.physics.mechanics.inertia import inertia_of_point_mass, Inertia +from sympy.utilities.exceptions import sympy_deprecation_warning + +__all__ = ['RigidBody'] + + +class RigidBody(BodyBase): + """An idealized rigid body. + + Explanation + =========== + + This is essentially a container which holds the various components which + describe a rigid body: a name, mass, center of mass, reference frame, and + inertia. + + All of these need to be supplied on creation, but can be changed + afterwards. + + Attributes + ========== + + name : string + The body's name. + masscenter : Point + The point which represents the center of mass of the rigid body. + frame : ReferenceFrame + The ReferenceFrame which the rigid body is fixed in. + mass : Sympifyable + The body's mass. + inertia : (Dyadic, Point) + The body's inertia about a point; stored in a tuple as shown above. + potential_energy : Sympifyable + The potential energy of the RigidBody. + + Examples + ======== + + >>> from sympy import Symbol + >>> from sympy.physics.mechanics import ReferenceFrame, Point, RigidBody + >>> from sympy.physics.mechanics import outer + >>> m = Symbol('m') + >>> A = ReferenceFrame('A') + >>> P = Point('P') + >>> I = outer (A.x, A.x) + >>> inertia_tuple = (I, P) + >>> B = RigidBody('B', P, A, m, inertia_tuple) + >>> # Or you could change them afterwards + >>> m2 = Symbol('m2') + >>> B.mass = m2 + + """ + + def __init__(self, name, masscenter=None, frame=None, mass=None, + inertia=None): + super().__init__(name, masscenter, mass) + if frame is None: + frame = ReferenceFrame(f'{name}_frame') + self.frame = frame + if inertia is None: + ixx = Symbol(f'{name}_ixx') + iyy = Symbol(f'{name}_iyy') + izz = Symbol(f'{name}_izz') + izx = Symbol(f'{name}_izx') + ixy = Symbol(f'{name}_ixy') + iyz = Symbol(f'{name}_iyz') + inertia = Inertia.from_inertia_scalars(self.masscenter, self.frame, + ixx, iyy, izz, ixy, iyz, izx) + self.inertia = inertia + + def __repr__(self): + return (f'{self.__class__.__name__}({repr(self.name)}, masscenter=' + f'{repr(self.masscenter)}, frame={repr(self.frame)}, mass=' + f'{repr(self.mass)}, inertia={repr(self.inertia)})') + + @property + def frame(self): + """The ReferenceFrame fixed to the body.""" + return self._frame + + @frame.setter + def frame(self, F): + if not isinstance(F, ReferenceFrame): + raise TypeError("RigidBody frame must be a ReferenceFrame object.") + self._frame = F + + @property + def x(self): + """The basis Vector for the body, in the x direction. """ + return self.frame.x + + @property + def y(self): + """The basis Vector for the body, in the y direction. """ + return self.frame.y + + @property + def z(self): + """The basis Vector for the body, in the z direction. """ + return self.frame.z + + @property + def inertia(self): + """The body's inertia about a point; stored as (Dyadic, Point).""" + return self._inertia + + @inertia.setter + def inertia(self, I): + # check if I is of the form (Dyadic, Point) + if len(I) != 2 or not isinstance(I[0], Dyadic) or not isinstance(I[1], Point): + raise TypeError("RigidBody inertia must be a tuple of the form (Dyadic, Point).") + + self._inertia = Inertia(I[0], I[1]) + # have I S/O, want I S/S* + # I S/O = I S/S* + I S*/O; I S/S* = I S/O - I S*/O + # I_S/S* = I_S/O - I_S*/O + I_Ss_O = inertia_of_point_mass(self.mass, + self.masscenter.pos_from(I[1]), + self.frame) + self._central_inertia = I[0] - I_Ss_O + + @property + def central_inertia(self): + """The body's central inertia dyadic.""" + return self._central_inertia + + @central_inertia.setter + def central_inertia(self, I): + if not isinstance(I, Dyadic): + raise TypeError("RigidBody inertia must be a Dyadic object.") + self.inertia = Inertia(I, self.masscenter) + + def linear_momentum(self, frame): + """ Linear momentum of the rigid body. + + Explanation + =========== + + The linear momentum L, of a rigid body B, with respect to frame N is + given by: + + ``L = m * v`` + + where m is the mass of the rigid body, and v is the velocity of the mass + center of B in the frame N. + + Parameters + ========== + + frame : ReferenceFrame + The frame in which linear momentum is desired. + + Examples + ======== + + >>> from sympy.physics.mechanics import Point, ReferenceFrame, outer + >>> from sympy.physics.mechanics import RigidBody, dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> m, v = dynamicsymbols('m v') + >>> N = ReferenceFrame('N') + >>> P = Point('P') + >>> P.set_vel(N, v * N.x) + >>> I = outer (N.x, N.x) + >>> Inertia_tuple = (I, P) + >>> B = RigidBody('B', P, N, m, Inertia_tuple) + >>> B.linear_momentum(N) + m*v*N.x + + """ + + return self.mass * self.masscenter.vel(frame) + + def angular_momentum(self, point, frame): + """Returns the angular momentum of the rigid body about a point in the + given frame. + + Explanation + =========== + + The angular momentum H of a rigid body B about some point O in a frame N + is given by: + + ``H = dot(I, w) + cross(r, m * v)`` + + where I and m are the central inertia dyadic and mass of rigid body B, w + is the angular velocity of body B in the frame N, r is the position + vector from point O to the mass center of B, and v is the velocity of + the mass center in the frame N. + + Parameters + ========== + + point : Point + The point about which angular momentum is desired. + frame : ReferenceFrame + The frame in which angular momentum is desired. + + Examples + ======== + + >>> from sympy.physics.mechanics import Point, ReferenceFrame, outer + >>> from sympy.physics.mechanics import RigidBody, dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> m, v, r, omega = dynamicsymbols('m v r omega') + >>> N = ReferenceFrame('N') + >>> b = ReferenceFrame('b') + >>> b.set_ang_vel(N, omega * b.x) + >>> P = Point('P') + >>> P.set_vel(N, 1 * N.x) + >>> I = outer(b.x, b.x) + >>> B = RigidBody('B', P, b, m, (I, P)) + >>> B.angular_momentum(P, N) + omega*b.x + + """ + I = self.central_inertia + w = self.frame.ang_vel_in(frame) + m = self.mass + r = self.masscenter.pos_from(point) + v = self.masscenter.vel(frame) + + return I.dot(w) + r.cross(m * v) + + def kinetic_energy(self, frame): + """Kinetic energy of the rigid body. + + Explanation + =========== + + The kinetic energy, T, of a rigid body, B, is given by: + + ``T = 1/2 * (dot(dot(I, w), w) + dot(m * v, v))`` + + where I and m are the central inertia dyadic and mass of rigid body B + respectively, w is the body's angular velocity, and v is the velocity of + the body's mass center in the supplied ReferenceFrame. + + Parameters + ========== + + frame : ReferenceFrame + The RigidBody's angular velocity and the velocity of it's mass + center are typically defined with respect to an inertial frame but + any relevant frame in which the velocities are known can be + supplied. + + Examples + ======== + + >>> from sympy.physics.mechanics import Point, ReferenceFrame, outer + >>> from sympy.physics.mechanics import RigidBody + >>> from sympy import symbols + >>> m, v, r, omega = symbols('m v r omega') + >>> N = ReferenceFrame('N') + >>> b = ReferenceFrame('b') + >>> b.set_ang_vel(N, omega * b.x) + >>> P = Point('P') + >>> P.set_vel(N, v * N.x) + >>> I = outer (b.x, b.x) + >>> inertia_tuple = (I, P) + >>> B = RigidBody('B', P, b, m, inertia_tuple) + >>> B.kinetic_energy(N) + m*v**2/2 + omega**2/2 + + """ + + rotational_KE = S.Half * dot( + self.frame.ang_vel_in(frame), + dot(self.central_inertia, self.frame.ang_vel_in(frame))) + translational_KE = S.Half * self.mass * dot(self.masscenter.vel(frame), + self.masscenter.vel(frame)) + return rotational_KE + translational_KE + + def set_potential_energy(self, scalar): + sympy_deprecation_warning( + """ +The sympy.physics.mechanics.RigidBody.set_potential_energy() +method is deprecated. Instead use + + B.potential_energy = scalar + """, + deprecated_since_version="1.5", + active_deprecations_target="deprecated-set-potential-energy", + ) + self.potential_energy = scalar + + def parallel_axis(self, point, frame=None): + """Returns the inertia dyadic of the body with respect to another point. + + Parameters + ========== + + point : sympy.physics.vector.Point + The point to express the inertia dyadic about. + frame : sympy.physics.vector.ReferenceFrame + The reference frame used to construct the dyadic. + + Returns + ======= + + inertia : sympy.physics.vector.Dyadic + The inertia dyadic of the rigid body expressed about the provided + point. + + """ + if frame is None: + frame = self.frame + return self.central_inertia + inertia_of_point_mass( + self.mass, self.masscenter.pos_from(point), frame) diff --git a/lib/python3.12/site-packages/sympy/physics/mechanics/system.py b/lib/python3.12/site-packages/sympy/physics/mechanics/system.py new file mode 100644 index 0000000000000000000000000000000000000000..c8e0657d7da54ca5aaad9b37b816235641968470 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/mechanics/system.py @@ -0,0 +1,1553 @@ +from functools import wraps + +from sympy.core.basic import Basic +from sympy.matrices.immutable import ImmutableMatrix +from sympy.matrices.dense import Matrix, eye, zeros +from sympy.core.containers import OrderedSet +from sympy.physics.mechanics.actuator import ActuatorBase +from sympy.physics.mechanics.body_base import BodyBase +from sympy.physics.mechanics.functions import ( + Lagrangian, _validate_coordinates, find_dynamicsymbols) +from sympy.physics.mechanics.joint import Joint +from sympy.physics.mechanics.kane import KanesMethod +from sympy.physics.mechanics.lagrange import LagrangesMethod +from sympy.physics.mechanics.loads import _parse_load, gravity +from sympy.physics.mechanics.method import _Methods +from sympy.physics.mechanics.particle import Particle +from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols +from sympy.utilities.iterables import iterable +from sympy.utilities.misc import filldedent + +__all__ = ['SymbolicSystem', 'System'] + + +def _reset_eom_method(method): + """Decorator to reset the eom_method if a property is changed.""" + + @wraps(method) + def wrapper(self, *args, **kwargs): + self._eom_method = None + return method(self, *args, **kwargs) + + return wrapper + + +class System(_Methods): + """Class to define a multibody system and form its equations of motion. + + Explanation + =========== + + A ``System`` instance stores the different objects associated with a model, + including bodies, joints, constraints, and other relevant information. With + all the relationships between components defined, the ``System`` can be used + to form the equations of motion using a backend, such as ``KanesMethod``. + The ``System`` has been designed to be compatible with third-party + libraries for greater flexibility and integration with other tools. + + Attributes + ========== + + frame : ReferenceFrame + Inertial reference frame of the system. + fixed_point : Point + A fixed point in the inertial reference frame. + x : Vector + Unit vector fixed in the inertial reference frame. + y : Vector + Unit vector fixed in the inertial reference frame. + z : Vector + Unit vector fixed in the inertial reference frame. + q : ImmutableMatrix + Matrix of all the generalized coordinates, i.e. the independent + generalized coordinates stacked upon the dependent. + u : ImmutableMatrix + Matrix of all the generalized speeds, i.e. the independent generealized + speeds stacked upon the dependent. + q_ind : ImmutableMatrix + Matrix of the independent generalized coordinates. + q_dep : ImmutableMatrix + Matrix of the dependent generalized coordinates. + u_ind : ImmutableMatrix + Matrix of the independent generalized speeds. + u_dep : ImmutableMatrix + Matrix of the dependent generalized speeds. + u_aux : ImmutableMatrix + Matrix of auxiliary generalized speeds. + kdes : ImmutableMatrix + Matrix of the kinematical differential equations as expressions equated + to the zero matrix. + bodies : tuple of BodyBase subclasses + Tuple of all bodies that make up the system. + joints : tuple of Joint + Tuple of all joints that connect bodies in the system. + loads : tuple of LoadBase subclasses + Tuple of all loads that have been applied to the system. + actuators : tuple of ActuatorBase subclasses + Tuple of all actuators present in the system. + holonomic_constraints : ImmutableMatrix + Matrix with the holonomic constraints as expressions equated to the zero + matrix. + nonholonomic_constraints : ImmutableMatrix + Matrix with the nonholonomic constraints as expressions equated to the + zero matrix. + velocity_constraints : ImmutableMatrix + Matrix with the velocity constraints as expressions equated to the zero + matrix. These are by default derived as the time derivatives of the + holonomic constraints extended with the nonholonomic constraints. + eom_method : subclass of KanesMethod or LagrangesMethod + Backend for forming the equations of motion. + + Examples + ======== + + In the example below a cart with a pendulum is created. The cart moves along + the x axis of the rail and the pendulum rotates about the z axis. The length + of the pendulum is ``l`` with the pendulum represented as a particle. To + move the cart a time dependent force ``F`` is applied to the cart. + + We first need to import some functions and create some of our variables. + + >>> from sympy import symbols, simplify + >>> from sympy.physics.mechanics import ( + ... mechanics_printing, dynamicsymbols, RigidBody, Particle, + ... ReferenceFrame, PrismaticJoint, PinJoint, System) + >>> mechanics_printing(pretty_print=False) + >>> g, l = symbols('g l') + >>> F = dynamicsymbols('F') + + The next step is to create bodies. It is also useful to create a frame for + locating the particle with respect to the pin joint later on, as a particle + does not have a body-fixed frame. + + >>> rail = RigidBody('rail') + >>> cart = RigidBody('cart') + >>> bob = Particle('bob') + >>> bob_frame = ReferenceFrame('bob_frame') + + Initialize the system, with the rail as the Newtonian reference. The body is + also automatically added to the system. + + >>> system = System.from_newtonian(rail) + >>> print(system.bodies[0]) + rail + + Create the joints, while immediately also adding them to the system. + + >>> system.add_joints( + ... PrismaticJoint('slider', rail, cart, joint_axis=rail.x), + ... PinJoint('pin', cart, bob, joint_axis=cart.z, + ... child_interframe=bob_frame, + ... child_point=l * bob_frame.y) + ... ) + >>> system.joints + (PrismaticJoint: slider parent: rail child: cart, + PinJoint: pin parent: cart child: bob) + + While adding the joints, the associated generalized coordinates, generalized + speeds, kinematic differential equations and bodies are also added to the + system. + + >>> system.q + Matrix([ + [q_slider], + [ q_pin]]) + >>> system.u + Matrix([ + [u_slider], + [ u_pin]]) + >>> system.kdes + Matrix([ + [u_slider - q_slider'], + [ u_pin - q_pin']]) + >>> [body.name for body in system.bodies] + ['rail', 'cart', 'bob'] + + With the kinematics established, we can now apply gravity and the cart force + ``F``. + + >>> system.apply_uniform_gravity(-g * system.y) + >>> system.add_loads((cart.masscenter, F * rail.x)) + >>> system.loads + ((rail_masscenter, - g*rail_mass*rail_frame.y), + (cart_masscenter, - cart_mass*g*rail_frame.y), + (bob_masscenter, - bob_mass*g*rail_frame.y), + (cart_masscenter, F*rail_frame.x)) + + With the entire system defined, we can now form the equations of motion. + Before forming the equations of motion, one can also run some checks that + will try to identify some common errors. + + >>> system.validate_system() + >>> system.form_eoms() + Matrix([ + [bob_mass*l*u_pin**2*sin(q_pin) - bob_mass*l*cos(q_pin)*u_pin' + - (bob_mass + cart_mass)*u_slider' + F], + [ -bob_mass*g*l*sin(q_pin) - bob_mass*l**2*u_pin' + - bob_mass*l*cos(q_pin)*u_slider']]) + >>> simplify(system.mass_matrix) + Matrix([ + [ bob_mass + cart_mass, bob_mass*l*cos(q_pin)], + [bob_mass*l*cos(q_pin), bob_mass*l**2]]) + >>> system.forcing + Matrix([ + [bob_mass*l*u_pin**2*sin(q_pin) + F], + [ -bob_mass*g*l*sin(q_pin)]]) + + The complexity of the above example can be increased if we add a constraint + to prevent the particle from moving in the horizontal (x) direction. This + can be done by adding a holonomic constraint. After which we should also + redefine what our (in)dependent generalized coordinates and speeds are. + + >>> system.add_holonomic_constraints( + ... bob.masscenter.pos_from(rail.masscenter).dot(system.x) + ... ) + >>> system.q_ind = system.get_joint('pin').coordinates + >>> system.q_dep = system.get_joint('slider').coordinates + >>> system.u_ind = system.get_joint('pin').speeds + >>> system.u_dep = system.get_joint('slider').speeds + + With the updated system the equations of motion can be formed again. + + >>> system.validate_system() + >>> system.form_eoms() + Matrix([[-bob_mass*g*l*sin(q_pin) + - bob_mass*l**2*u_pin' + - bob_mass*l*cos(q_pin)*u_slider' + - l*(bob_mass*l*u_pin**2*sin(q_pin) + - bob_mass*l*cos(q_pin)*u_pin' + - (bob_mass + cart_mass)*u_slider')*cos(q_pin) + - l*F*cos(q_pin)]]) + >>> simplify(system.mass_matrix) + Matrix([ + [bob_mass*l**2*sin(q_pin)**2, -cart_mass*l*cos(q_pin)], + [ l*cos(q_pin), 1]]) + >>> simplify(system.forcing) + Matrix([ + [-l*(bob_mass*g*sin(q_pin) + bob_mass*l*u_pin**2*sin(2*q_pin)/2 + + F*cos(q_pin))], + [ + l*u_pin**2*sin(q_pin)]]) + + """ + + def __init__(self, frame=None, fixed_point=None): + """Initialize the system. + + Parameters + ========== + + frame : ReferenceFrame, optional + The inertial frame of the system. If none is supplied, a new frame + will be created. + fixed_point : Point, optional + A fixed point in the inertial reference frame. If none is supplied, + a new fixed_point will be created. + + """ + if frame is None: + frame = ReferenceFrame('inertial_frame') + elif not isinstance(frame, ReferenceFrame): + raise TypeError('Frame must be an instance of ReferenceFrame.') + self._frame = frame + if fixed_point is None: + fixed_point = Point('inertial_point') + elif not isinstance(fixed_point, Point): + raise TypeError('Fixed point must be an instance of Point.') + self._fixed_point = fixed_point + self._fixed_point.set_vel(self._frame, 0) + self._q_ind = ImmutableMatrix(1, 0, []).T + self._q_dep = ImmutableMatrix(1, 0, []).T + self._u_ind = ImmutableMatrix(1, 0, []).T + self._u_dep = ImmutableMatrix(1, 0, []).T + self._u_aux = ImmutableMatrix(1, 0, []).T + self._kdes = ImmutableMatrix(1, 0, []).T + self._hol_coneqs = ImmutableMatrix(1, 0, []).T + self._nonhol_coneqs = ImmutableMatrix(1, 0, []).T + self._vel_constrs = None + self._bodies = [] + self._joints = [] + self._loads = [] + self._actuators = [] + self._eom_method = None + + @classmethod + def from_newtonian(cls, newtonian): + """Constructs the system with respect to a Newtonian body.""" + if isinstance(newtonian, Particle): + raise TypeError('A Particle has no frame so cannot act as ' + 'the Newtonian.') + system = cls(frame=newtonian.frame, fixed_point=newtonian.masscenter) + system.add_bodies(newtonian) + return system + + @property + def fixed_point(self): + """Fixed point in the inertial reference frame.""" + return self._fixed_point + + @property + def frame(self): + """Inertial reference frame of the system.""" + return self._frame + + @property + def x(self): + """Unit vector fixed in the inertial reference frame.""" + return self._frame.x + + @property + def y(self): + """Unit vector fixed in the inertial reference frame.""" + return self._frame.y + + @property + def z(self): + """Unit vector fixed in the inertial reference frame.""" + return self._frame.z + + @property + def bodies(self): + """Tuple of all bodies that have been added to the system.""" + return tuple(self._bodies) + + @bodies.setter + @_reset_eom_method + def bodies(self, bodies): + bodies = self._objects_to_list(bodies) + self._check_objects(bodies, [], BodyBase, 'Bodies', 'bodies') + self._bodies = bodies + + @property + def joints(self): + """Tuple of all joints that have been added to the system.""" + return tuple(self._joints) + + @joints.setter + @_reset_eom_method + def joints(self, joints): + joints = self._objects_to_list(joints) + self._check_objects(joints, [], Joint, 'Joints', 'joints') + self._joints = [] + self.add_joints(*joints) + + @property + def loads(self): + """Tuple of loads that have been applied on the system.""" + return tuple(self._loads) + + @loads.setter + @_reset_eom_method + def loads(self, loads): + loads = self._objects_to_list(loads) + self._loads = [_parse_load(load) for load in loads] + + @property + def actuators(self): + """Tuple of actuators present in the system.""" + return tuple(self._actuators) + + @actuators.setter + @_reset_eom_method + def actuators(self, actuators): + actuators = self._objects_to_list(actuators) + self._check_objects(actuators, [], ActuatorBase, 'Actuators', + 'actuators') + self._actuators = actuators + + @property + def q(self): + """Matrix of all the generalized coordinates with the independent + stacked upon the dependent.""" + return self._q_ind.col_join(self._q_dep) + + @property + def u(self): + """Matrix of all the generalized speeds with the independent stacked + upon the dependent.""" + return self._u_ind.col_join(self._u_dep) + + @property + def q_ind(self): + """Matrix of the independent generalized coordinates.""" + return self._q_ind + + @q_ind.setter + @_reset_eom_method + def q_ind(self, q_ind): + self._q_ind, self._q_dep = self._parse_coordinates( + self._objects_to_list(q_ind), True, [], self.q_dep, 'coordinates') + + @property + def q_dep(self): + """Matrix of the dependent generalized coordinates.""" + return self._q_dep + + @q_dep.setter + @_reset_eom_method + def q_dep(self, q_dep): + self._q_ind, self._q_dep = self._parse_coordinates( + self._objects_to_list(q_dep), False, self.q_ind, [], 'coordinates') + + @property + def u_ind(self): + """Matrix of the independent generalized speeds.""" + return self._u_ind + + @u_ind.setter + @_reset_eom_method + def u_ind(self, u_ind): + self._u_ind, self._u_dep = self._parse_coordinates( + self._objects_to_list(u_ind), True, [], self.u_dep, 'speeds') + + @property + def u_dep(self): + """Matrix of the dependent generalized speeds.""" + return self._u_dep + + @u_dep.setter + @_reset_eom_method + def u_dep(self, u_dep): + self._u_ind, self._u_dep = self._parse_coordinates( + self._objects_to_list(u_dep), False, self.u_ind, [], 'speeds') + + @property + def u_aux(self): + """Matrix of auxiliary generalized speeds.""" + return self._u_aux + + @u_aux.setter + @_reset_eom_method + def u_aux(self, u_aux): + self._u_aux = self._parse_coordinates( + self._objects_to_list(u_aux), True, [], [], 'u_auxiliary')[0] + + @property + def kdes(self): + """Kinematical differential equations as expressions equated to the zero + matrix. These equations describe the coupling between the generalized + coordinates and the generalized speeds.""" + return self._kdes + + @kdes.setter + @_reset_eom_method + def kdes(self, kdes): + kdes = self._objects_to_list(kdes) + self._kdes = self._parse_expressions( + kdes, [], 'kinematic differential equations') + + @property + def holonomic_constraints(self): + """Matrix with the holonomic constraints as expressions equated to the + zero matrix.""" + return self._hol_coneqs + + @holonomic_constraints.setter + @_reset_eom_method + def holonomic_constraints(self, constraints): + constraints = self._objects_to_list(constraints) + self._hol_coneqs = self._parse_expressions( + constraints, [], 'holonomic constraints') + + @property + def nonholonomic_constraints(self): + """Matrix with the nonholonomic constraints as expressions equated to + the zero matrix.""" + return self._nonhol_coneqs + + @nonholonomic_constraints.setter + @_reset_eom_method + def nonholonomic_constraints(self, constraints): + constraints = self._objects_to_list(constraints) + self._nonhol_coneqs = self._parse_expressions( + constraints, [], 'nonholonomic constraints') + + @property + def velocity_constraints(self): + """Matrix with the velocity constraints as expressions equated to the + zero matrix. The velocity constraints are by default derived from the + holonomic and nonholonomic constraints unless they are explicitly set. + """ + if self._vel_constrs is None: + return self.holonomic_constraints.diff(dynamicsymbols._t).col_join( + self.nonholonomic_constraints) + return self._vel_constrs + + @velocity_constraints.setter + @_reset_eom_method + def velocity_constraints(self, constraints): + if constraints is None: + self._vel_constrs = None + return + constraints = self._objects_to_list(constraints) + self._vel_constrs = self._parse_expressions( + constraints, [], 'velocity constraints') + + @property + def eom_method(self): + """Backend for forming the equations of motion.""" + return self._eom_method + + @staticmethod + def _objects_to_list(lst): + """Helper to convert passed objects to a list.""" + if not iterable(lst): # Only one object + return [lst] + return list(lst[:]) # converts Matrix and tuple to flattened list + + @staticmethod + def _check_objects(objects, obj_lst, expected_type, obj_name, type_name): + """Helper to check the objects that are being added to the system. + + Explanation + =========== + This method checks that the objects that are being added to the system + are of the correct type and have not already been added. If any of the + objects are not of the correct type or have already been added, then + an error is raised. + + Parameters + ========== + objects : iterable + The objects that would be added to the system. + obj_lst : list + The list of objects that are already in the system. + expected_type : type + The type that the objects should be. + obj_name : str + The name of the category of objects. This string is used to + formulate the error message for the user. + type_name : str + The name of the type that the objects should be. This string is used + to formulate the error message for the user. + + """ + seen = set(obj_lst) + duplicates = set() + wrong_types = set() + for obj in objects: + if not isinstance(obj, expected_type): + wrong_types.add(obj) + if obj in seen: + duplicates.add(obj) + else: + seen.add(obj) + if wrong_types: + raise TypeError(f'{obj_name} {wrong_types} are not {type_name}.') + if duplicates: + raise ValueError(f'{obj_name} {duplicates} have already been added ' + f'to the system.') + + def _parse_coordinates(self, new_coords, independent, old_coords_ind, + old_coords_dep, coord_type='coordinates'): + """Helper to parse coordinates and speeds.""" + # Construct lists of the independent and dependent coordinates + coords_ind, coords_dep = old_coords_ind[:], old_coords_dep[:] + if not iterable(independent): + independent = [independent] * len(new_coords) + for coord, indep in zip(new_coords, independent): + if indep: + coords_ind.append(coord) + else: + coords_dep.append(coord) + # Check types and duplicates + current = {'coordinates': self.q_ind[:] + self.q_dep[:], + 'speeds': self.u_ind[:] + self.u_dep[:], + 'u_auxiliary': self._u_aux[:], + coord_type: coords_ind + coords_dep} + _validate_coordinates(**current) + return (ImmutableMatrix(1, len(coords_ind), coords_ind).T, + ImmutableMatrix(1, len(coords_dep), coords_dep).T) + + @staticmethod + def _parse_expressions(new_expressions, old_expressions, name, + check_negatives=False): + """Helper to parse expressions like constraints.""" + old_expressions = old_expressions[:] + new_expressions = list(new_expressions) # Converts a possible tuple + if check_negatives: + check_exprs = old_expressions + [-expr for expr in old_expressions] + else: + check_exprs = old_expressions + System._check_objects(new_expressions, check_exprs, Basic, name, + 'expressions') + for expr in new_expressions: + if expr == 0: + raise ValueError(f'Parsed {name} are zero.') + return ImmutableMatrix(1, len(old_expressions) + len(new_expressions), + old_expressions + new_expressions).T + + @_reset_eom_method + def add_coordinates(self, *coordinates, independent=True): + """Add generalized coordinate(s) to the system. + + Parameters + ========== + + *coordinates : dynamicsymbols + One or more generalized coordinates to be added to the system. + independent : bool or list of bool, optional + Boolean whether a coordinate is dependent or independent. The + default is True, so the coordinates are added as independent by + default. + + """ + self._q_ind, self._q_dep = self._parse_coordinates( + coordinates, independent, self.q_ind, self.q_dep, 'coordinates') + + @_reset_eom_method + def add_speeds(self, *speeds, independent=True): + """Add generalized speed(s) to the system. + + Parameters + ========== + + *speeds : dynamicsymbols + One or more generalized speeds to be added to the system. + independent : bool or list of bool, optional + Boolean whether a speed is dependent or independent. The default is + True, so the speeds are added as independent by default. + + """ + self._u_ind, self._u_dep = self._parse_coordinates( + speeds, independent, self.u_ind, self.u_dep, 'speeds') + + @_reset_eom_method + def add_auxiliary_speeds(self, *speeds): + """Add auxiliary speed(s) to the system. + + Parameters + ========== + + *speeds : dynamicsymbols + One or more auxiliary speeds to be added to the system. + + """ + self._u_aux = self._parse_coordinates( + speeds, True, self._u_aux, [], 'u_auxiliary')[0] + + @_reset_eom_method + def add_kdes(self, *kdes): + """Add kinematic differential equation(s) to the system. + + Parameters + ========== + + *kdes : Expr + One or more kinematic differential equations. + + """ + self._kdes = self._parse_expressions( + kdes, self.kdes, 'kinematic differential equations', + check_negatives=True) + + @_reset_eom_method + def add_holonomic_constraints(self, *constraints): + """Add holonomic constraint(s) to the system. + + Parameters + ========== + + *constraints : Expr + One or more holonomic constraints, which are expressions that should + be zero. + + """ + self._hol_coneqs = self._parse_expressions( + constraints, self._hol_coneqs, 'holonomic constraints', + check_negatives=True) + + @_reset_eom_method + def add_nonholonomic_constraints(self, *constraints): + """Add nonholonomic constraint(s) to the system. + + Parameters + ========== + + *constraints : Expr + One or more nonholonomic constraints, which are expressions that + should be zero. + + """ + self._nonhol_coneqs = self._parse_expressions( + constraints, self._nonhol_coneqs, 'nonholonomic constraints', + check_negatives=True) + + @_reset_eom_method + def add_bodies(self, *bodies): + """Add body(ies) to the system. + + Parameters + ========== + + bodies : Particle or RigidBody + One or more bodies. + + """ + self._check_objects(bodies, self.bodies, BodyBase, 'Bodies', 'bodies') + self._bodies.extend(bodies) + + @_reset_eom_method + def add_loads(self, *loads): + """Add load(s) to the system. + + Parameters + ========== + + *loads : Force or Torque + One or more loads. + + """ + loads = [_parse_load(load) for load in loads] # Checks the loads + self._loads.extend(loads) + + @_reset_eom_method + def apply_uniform_gravity(self, acceleration): + """Apply uniform gravity to all bodies in the system by adding loads. + + Parameters + ========== + + acceleration : Vector + The acceleration due to gravity. + + """ + self.add_loads(*gravity(acceleration, *self.bodies)) + + @_reset_eom_method + def add_actuators(self, *actuators): + """Add actuator(s) to the system. + + Parameters + ========== + + *actuators : subclass of ActuatorBase + One or more actuators. + + """ + self._check_objects(actuators, self.actuators, ActuatorBase, + 'Actuators', 'actuators') + self._actuators.extend(actuators) + + @_reset_eom_method + def add_joints(self, *joints): + """Add joint(s) to the system. + + Explanation + =========== + + This methods adds one or more joints to the system including its + associated objects, i.e. generalized coordinates, generalized speeds, + kinematic differential equations and the bodies. + + Parameters + ========== + + *joints : subclass of Joint + One or more joints. + + Notes + ===== + + For the generalized coordinates, generalized speeds and bodies it is + checked whether they are already known by the system instance. If they + are, then they are not added. The kinematic differential equations are + however always added to the system, so you should not also manually add + those on beforehand. + + """ + self._check_objects(joints, self.joints, Joint, 'Joints', 'joints') + self._joints.extend(joints) + coordinates, speeds, kdes, bodies = (OrderedSet() for _ in range(4)) + for joint in joints: + coordinates.update(joint.coordinates) + speeds.update(joint.speeds) + kdes.update(joint.kdes) + bodies.update((joint.parent, joint.child)) + coordinates = coordinates.difference(self.q) + speeds = speeds.difference(self.u) + kdes = kdes.difference(self.kdes[:] + (-self.kdes)[:]) + bodies = bodies.difference(self.bodies) + self.add_coordinates(*tuple(coordinates)) + self.add_speeds(*tuple(speeds)) + self.add_kdes(*(kde for kde in tuple(kdes) if not kde == 0)) + self.add_bodies(*tuple(bodies)) + + def get_body(self, name): + """Retrieve a body from the system by name. + + Parameters + ========== + + name : str + The name of the body to retrieve. + + Returns + ======= + + RigidBody or Particle + The body with the given name, or None if no such body exists. + + """ + for body in self._bodies: + if body.name == name: + return body + + def get_joint(self, name): + """Retrieve a joint from the system by name. + + Parameters + ========== + + name : str + The name of the joint to retrieve. + + Returns + ======= + + subclass of Joint + The joint with the given name, or None if no such joint exists. + + """ + for joint in self._joints: + if joint.name == name: + return joint + + def _form_eoms(self): + return self.form_eoms() + + def form_eoms(self, eom_method=KanesMethod, **kwargs): + """Form the equations of motion of the system. + + Parameters + ========== + + eom_method : subclass of KanesMethod or LagrangesMethod + Backend class to be used for forming the equations of motion. The + default is ``KanesMethod``. + + Returns + ======== + + ImmutableMatrix + Vector of equations of motions. + + Examples + ======== + + This is a simple example for a one degree of freedom translational + spring-mass-damper. + + >>> from sympy import S, symbols + >>> from sympy.physics.mechanics import ( + ... LagrangesMethod, dynamicsymbols, PrismaticJoint, Particle, + ... RigidBody, System) + >>> q = dynamicsymbols('q') + >>> qd = dynamicsymbols('q', 1) + >>> m, k, b = symbols('m k b') + >>> wall = RigidBody('W') + >>> system = System.from_newtonian(wall) + >>> bob = Particle('P', mass=m) + >>> bob.potential_energy = S.Half * k * q**2 + >>> system.add_joints(PrismaticJoint('J', wall, bob, q, qd)) + >>> system.add_loads((bob.masscenter, b * qd * system.x)) + >>> system.form_eoms(LagrangesMethod) + Matrix([[-b*Derivative(q(t), t) + k*q(t) + m*Derivative(q(t), (t, 2))]]) + + We can also solve for the states using the 'rhs' method. + + >>> system.rhs() + Matrix([ + [ Derivative(q(t), t)], + [(b*Derivative(q(t), t) - k*q(t))/m]]) + + """ + # KanesMethod does not accept empty iterables + loads = self.loads + tuple( + load for act in self.actuators for load in act.to_loads()) + loads = loads if loads else None + if issubclass(eom_method, KanesMethod): + disallowed_kwargs = { + "frame", "q_ind", "u_ind", "kd_eqs", "q_dependent", + "u_dependent", "u_auxiliary", "configuration_constraints", + "velocity_constraints", "forcelist", "bodies"} + wrong_kwargs = disallowed_kwargs.intersection(kwargs) + if wrong_kwargs: + raise ValueError( + f"The following keyword arguments are not allowed to be " + f"overwritten in {eom_method.__name__}: {wrong_kwargs}.") + kwargs = {"frame": self.frame, "q_ind": self.q_ind, + "u_ind": self.u_ind, "kd_eqs": self.kdes, + "q_dependent": self.q_dep, "u_dependent": self.u_dep, + "configuration_constraints": self.holonomic_constraints, + "velocity_constraints": self.velocity_constraints, + "u_auxiliary": self.u_aux, + "forcelist": loads, "bodies": self.bodies, + "explicit_kinematics": False, **kwargs} + self._eom_method = eom_method(**kwargs) + elif issubclass(eom_method, LagrangesMethod): + disallowed_kwargs = { + "frame", "qs", "forcelist", "bodies", "hol_coneqs", + "nonhol_coneqs", "Lagrangian"} + wrong_kwargs = disallowed_kwargs.intersection(kwargs) + if wrong_kwargs: + raise ValueError( + f"The following keyword arguments are not allowed to be " + f"overwritten in {eom_method.__name__}: {wrong_kwargs}.") + kwargs = {"frame": self.frame, "qs": self.q, "forcelist": loads, + "bodies": self.bodies, + "hol_coneqs": self.holonomic_constraints, + "nonhol_coneqs": self.nonholonomic_constraints, **kwargs} + if "Lagrangian" not in kwargs: + kwargs["Lagrangian"] = Lagrangian(kwargs["frame"], + *kwargs["bodies"]) + self._eom_method = eom_method(**kwargs) + else: + raise NotImplementedError(f'{eom_method} has not been implemented.') + return self.eom_method._form_eoms() + + def rhs(self, inv_method=None): + """Compute the equations of motion in the explicit form. + + Parameters + ========== + + inv_method : str + The specific sympy inverse matrix calculation method to use. For a + list of valid methods, see + :meth:`~sympy.matrices.matrixbase.MatrixBase.inv` + + Returns + ======== + + ImmutableMatrix + Equations of motion in the explicit form. + + See Also + ======== + + sympy.physics.mechanics.kane.KanesMethod.rhs: + KanesMethod's ``rhs`` function. + sympy.physics.mechanics.lagrange.LagrangesMethod.rhs: + LagrangesMethod's ``rhs`` function. + + """ + return self.eom_method.rhs(inv_method=inv_method) + + @property + def mass_matrix(self): + r"""The mass matrix of the system. + + Explanation + =========== + + The mass matrix $M_d$ and the forcing vector $f_d$ of a system describe + the system's dynamics according to the following equations: + + .. math:: + M_d \dot{u} = f_d + + where $\dot{u}$ is the time derivative of the generalized speeds. + + """ + return self.eom_method.mass_matrix + + @property + def mass_matrix_full(self): + r"""The mass matrix of the system, augmented by the kinematic + differential equations in explicit or implicit form. + + Explanation + =========== + + The full mass matrix $M_m$ and the full forcing vector $f_m$ of a system + describe the dynamics and kinematics according to the following + equation: + + .. math:: + M_m \dot{x} = f_m + + where $x$ is the state vector stacking $q$ and $u$. + + """ + return self.eom_method.mass_matrix_full + + @property + def forcing(self): + """The forcing vector of the system.""" + return self.eom_method.forcing + + @property + def forcing_full(self): + """The forcing vector of the system, augmented by the kinematic + differential equations in explicit or implicit form.""" + return self.eom_method.forcing_full + + def validate_system(self, eom_method=KanesMethod, check_duplicates=False): + """Validates the system using some basic checks. + + Explanation + =========== + + This method validates the system based on the following checks: + + - The number of dependent generalized coordinates should equal the + number of holonomic constraints. + - All generalized coordinates defined by the joints should also be known + to the system. + - If ``KanesMethod`` is used as a ``eom_method``: + - All generalized speeds and kinematic differential equations + defined by the joints should also be known to the system. + - The number of dependent generalized speeds should equal the number + of velocity constraints. + - The number of generalized coordinates should be less than or equal + to the number of generalized speeds. + - The number of generalized coordinates should equal the number of + kinematic differential equations. + - If ``LagrangesMethod`` is used as ``eom_method``: + - There should not be any generalized speeds that are not + derivatives of the generalized coordinates (this includes the + generalized speeds defined by the joints). + + Parameters + ========== + + eom_method : subclass of KanesMethod or LagrangesMethod + Backend class that will be used for forming the equations of motion. + There are different checks for the different backends. The default + is ``KanesMethod``. + check_duplicates : bool + Boolean whether the system should be checked for duplicate + definitions. The default is False, because duplicates are already + checked when adding objects to the system. + + Notes + ===== + + This method is not guaranteed to be backwards compatible as it may + improve over time. The method can become both more and less strict in + certain areas. However a well-defined system should always pass all + these tests. + + """ + msgs = [] + # Save some data in variables + n_hc = self.holonomic_constraints.shape[0] + n_vc = self.velocity_constraints.shape[0] + n_q_dep, n_u_dep = self.q_dep.shape[0], self.u_dep.shape[0] + q_set, u_set = set(self.q), set(self.u) + n_q, n_u = len(q_set), len(u_set) + # Check number of holonomic constraints + if n_q_dep != n_hc: + msgs.append(filldedent(f""" + The number of dependent generalized coordinates {n_q_dep} should be + equal to the number of holonomic constraints {n_hc}.""")) + # Check if all joint coordinates and speeds are present + missing_q = set() + for joint in self.joints: + missing_q.update(set(joint.coordinates).difference(q_set)) + if missing_q: + msgs.append(filldedent(f""" + The generalized coordinates {missing_q} used in joints are not added + to the system.""")) + # Method dependent checks + if issubclass(eom_method, KanesMethod): + n_kdes = len(self.kdes) + missing_kdes, missing_u = set(), set() + for joint in self.joints: + missing_u.update(set(joint.speeds).difference(u_set)) + missing_kdes.update(set(joint.kdes).difference( + self.kdes[:] + (-self.kdes)[:])) + if missing_u: + msgs.append(filldedent(f""" + The generalized speeds {missing_u} used in joints are not added + to the system.""")) + if missing_kdes: + msgs.append(filldedent(f""" + The kinematic differential equations {missing_kdes} used in + joints are not added to the system.""")) + if n_u_dep != n_vc: + msgs.append(filldedent(f""" + The number of dependent generalized speeds {n_u_dep} should be + equal to the number of velocity constraints {n_vc}.""")) + if n_q > n_u: + msgs.append(filldedent(f""" + The number of generalized coordinates {n_q} should be less than + or equal to the number of generalized speeds {n_u}.""")) + if n_u != n_kdes: + msgs.append(filldedent(f""" + The number of generalized speeds {n_u} should be equal to the + number of kinematic differential equations {n_kdes}.""")) + elif issubclass(eom_method, LagrangesMethod): + not_qdots = set(self.u).difference(self.q.diff(dynamicsymbols._t)) + for joint in self.joints: + not_qdots.update(set( + joint.speeds).difference(self.q.diff(dynamicsymbols._t))) + if not_qdots: + msgs.append(filldedent(f""" + The generalized speeds {not_qdots} are not supported by this + method. Only derivatives of the generalized coordinates are + supported. If these symbols are used in your expressions, then + this will result in wrong equations of motion.""")) + if self.u_aux: + msgs.append(filldedent(f""" + This method does not support auxiliary speeds. If these symbols + are used in your expressions, then this will result in wrong + equations of motion. The auxiliary speeds are {self.u_aux}.""")) + else: + raise NotImplementedError(f'{eom_method} has not been implemented.') + if check_duplicates: # Should be redundant + duplicates_to_check = [('generalized coordinates', self.q), + ('generalized speeds', self.u), + ('auxiliary speeds', self.u_aux), + ('bodies', self.bodies), + ('joints', self.joints)] + for name, lst in duplicates_to_check: + seen = set() + duplicates = {x for x in lst if x in seen or seen.add(x)} + if duplicates: + msgs.append(filldedent(f""" + The {name} {duplicates} exist multiple times within the + system.""")) + if msgs: + raise ValueError('\n'.join(msgs)) + + +class SymbolicSystem: + """SymbolicSystem is a class that contains all the information about a + system in a symbolic format such as the equations of motions and the bodies + and loads in the system. + + There are three ways that the equations of motion can be described for + Symbolic System: + + + [1] Explicit form where the kinematics and dynamics are combined + x' = F_1(x, t, r, p) + + [2] Implicit form where the kinematics and dynamics are combined + M_2(x, p) x' = F_2(x, t, r, p) + + [3] Implicit form where the kinematics and dynamics are separate + M_3(q, p) u' = F_3(q, u, t, r, p) + q' = G(q, u, t, r, p) + + where + + x : states, e.g. [q, u] + t : time + r : specified (exogenous) inputs + p : constants + q : generalized coordinates + u : generalized speeds + F_1 : right hand side of the combined equations in explicit form + F_2 : right hand side of the combined equations in implicit form + F_3 : right hand side of the dynamical equations in implicit form + M_2 : mass matrix of the combined equations in implicit form + M_3 : mass matrix of the dynamical equations in implicit form + G : right hand side of the kinematical differential equations + + Parameters + ========== + + coord_states : ordered iterable of functions of time + This input will either be a collection of the coordinates or states + of the system depending on whether or not the speeds are also + given. If speeds are specified this input will be assumed to + be the coordinates otherwise this input will be assumed to + be the states. + + right_hand_side : Matrix + This variable is the right hand side of the equations of motion in + any of the forms. The specific form will be assumed depending on + whether a mass matrix or coordinate derivatives are given. + + speeds : ordered iterable of functions of time, optional + This is a collection of the generalized speeds of the system. If + given it will be assumed that the first argument (coord_states) + will represent the generalized coordinates of the system. + + mass_matrix : Matrix, optional + The matrix of the implicit forms of the equations of motion (forms + [2] and [3]). The distinction between the forms is determined by + whether or not the coordinate derivatives are passed in. If + they are given form [3] will be assumed otherwise form [2] is + assumed. + + coordinate_derivatives : Matrix, optional + The right hand side of the kinematical equations in explicit form. + If given it will be assumed that the equations of motion are being + entered in form [3]. + + alg_con : Iterable, optional + The indexes of the rows in the equations of motion that contain + algebraic constraints instead of differential equations. If the + equations are input in form [3], it will be assumed the indexes are + referencing the mass_matrix/right_hand_side combination and not the + coordinate_derivatives. + + output_eqns : Dictionary, optional + Any output equations that are desired to be tracked are stored in a + dictionary where the key corresponds to the name given for the + specific equation and the value is the equation itself in symbolic + form + + coord_idxs : Iterable, optional + If coord_states corresponds to the states rather than the + coordinates this variable will tell SymbolicSystem which indexes of + the states correspond to generalized coordinates. + + speed_idxs : Iterable, optional + If coord_states corresponds to the states rather than the + coordinates this variable will tell SymbolicSystem which indexes of + the states correspond to generalized speeds. + + bodies : iterable of Body/Rigidbody objects, optional + Iterable containing the bodies of the system + + loads : iterable of load instances (described below), optional + Iterable containing the loads of the system where forces are given + by (point of application, force vector) and torques are given by + (reference frame acting upon, torque vector). Ex [(point, force), + (ref_frame, torque)] + + Attributes + ========== + + coordinates : Matrix, shape(n, 1) + This is a matrix containing the generalized coordinates of the system + + speeds : Matrix, shape(m, 1) + This is a matrix containing the generalized speeds of the system + + states : Matrix, shape(o, 1) + This is a matrix containing the state variables of the system + + alg_con : List + This list contains the indices of the algebraic constraints in the + combined equations of motion. The presence of these constraints + requires that a DAE solver be used instead of an ODE solver. + If the system is given in form [3] the alg_con variable will be + adjusted such that it is a representation of the combined kinematics + and dynamics thus make sure it always matches the mass matrix + entered. + + dyn_implicit_mat : Matrix, shape(m, m) + This is the M matrix in form [3] of the equations of motion (the mass + matrix or generalized inertia matrix of the dynamical equations of + motion in implicit form). + + dyn_implicit_rhs : Matrix, shape(m, 1) + This is the F vector in form [3] of the equations of motion (the right + hand side of the dynamical equations of motion in implicit form). + + comb_implicit_mat : Matrix, shape(o, o) + This is the M matrix in form [2] of the equations of motion. + This matrix contains a block diagonal structure where the top + left block (the first rows) represent the matrix in the + implicit form of the kinematical equations and the bottom right + block (the last rows) represent the matrix in the implicit form + of the dynamical equations. + + comb_implicit_rhs : Matrix, shape(o, 1) + This is the F vector in form [2] of the equations of motion. The top + part of the vector represents the right hand side of the implicit form + of the kinemaical equations and the bottom of the vector represents the + right hand side of the implicit form of the dynamical equations of + motion. + + comb_explicit_rhs : Matrix, shape(o, 1) + This vector represents the right hand side of the combined equations of + motion in explicit form (form [1] from above). + + kin_explicit_rhs : Matrix, shape(m, 1) + This is the right hand side of the explicit form of the kinematical + equations of motion as can be seen in form [3] (the G matrix). + + output_eqns : Dictionary + If output equations were given they are stored in a dictionary where + the key corresponds to the name given for the specific equation and + the value is the equation itself in symbolic form + + bodies : Tuple + If the bodies in the system were given they are stored in a tuple for + future access + + loads : Tuple + If the loads in the system were given they are stored in a tuple for + future access. This includes forces and torques where forces are given + by (point of application, force vector) and torques are given by + (reference frame acted upon, torque vector). + + Example + ======= + + As a simple example, the dynamics of a simple pendulum will be input into a + SymbolicSystem object manually. First some imports will be needed and then + symbols will be set up for the length of the pendulum (l), mass at the end + of the pendulum (m), and a constant for gravity (g). :: + + >>> from sympy import Matrix, sin, symbols + >>> from sympy.physics.mechanics import dynamicsymbols, SymbolicSystem + >>> l, m, g = symbols('l m g') + + The system will be defined by an angle of theta from the vertical and a + generalized speed of omega will be used where omega = theta_dot. :: + + >>> theta, omega = dynamicsymbols('theta omega') + + Now the equations of motion are ready to be formed and passed to the + SymbolicSystem object. :: + + >>> kin_explicit_rhs = Matrix([omega]) + >>> dyn_implicit_mat = Matrix([l**2 * m]) + >>> dyn_implicit_rhs = Matrix([-g * l * m * sin(theta)]) + >>> symsystem = SymbolicSystem([theta], dyn_implicit_rhs, [omega], + ... dyn_implicit_mat) + + Notes + ===== + + m : number of generalized speeds + n : number of generalized coordinates + o : number of states + + """ + + def __init__(self, coord_states, right_hand_side, speeds=None, + mass_matrix=None, coordinate_derivatives=None, alg_con=None, + output_eqns={}, coord_idxs=None, speed_idxs=None, bodies=None, + loads=None): + """Initializes a SymbolicSystem object""" + + # Extract information on speeds, coordinates and states + if speeds is None: + self._states = Matrix(coord_states) + + if coord_idxs is None: + self._coordinates = None + else: + coords = [coord_states[i] for i in coord_idxs] + self._coordinates = Matrix(coords) + + if speed_idxs is None: + self._speeds = None + else: + speeds_inter = [coord_states[i] for i in speed_idxs] + self._speeds = Matrix(speeds_inter) + else: + self._coordinates = Matrix(coord_states) + self._speeds = Matrix(speeds) + self._states = self._coordinates.col_join(self._speeds) + + # Extract equations of motion form + if coordinate_derivatives is not None: + self._kin_explicit_rhs = coordinate_derivatives + self._dyn_implicit_rhs = right_hand_side + self._dyn_implicit_mat = mass_matrix + self._comb_implicit_rhs = None + self._comb_implicit_mat = None + self._comb_explicit_rhs = None + elif mass_matrix is not None: + self._kin_explicit_rhs = None + self._dyn_implicit_rhs = None + self._dyn_implicit_mat = None + self._comb_implicit_rhs = right_hand_side + self._comb_implicit_mat = mass_matrix + self._comb_explicit_rhs = None + else: + self._kin_explicit_rhs = None + self._dyn_implicit_rhs = None + self._dyn_implicit_mat = None + self._comb_implicit_rhs = None + self._comb_implicit_mat = None + self._comb_explicit_rhs = right_hand_side + + # Set the remainder of the inputs as instance attributes + if alg_con is not None and coordinate_derivatives is not None: + alg_con = [i + len(coordinate_derivatives) for i in alg_con] + self._alg_con = alg_con + self.output_eqns = output_eqns + + # Change the body and loads iterables to tuples if they are not tuples + # already + if not isinstance(bodies, tuple) and bodies is not None: + bodies = tuple(bodies) + if not isinstance(loads, tuple) and loads is not None: + loads = tuple(loads) + self._bodies = bodies + self._loads = loads + + @property + def coordinates(self): + """Returns the column matrix of the generalized coordinates""" + if self._coordinates is None: + raise AttributeError("The coordinates were not specified.") + else: + return self._coordinates + + @property + def speeds(self): + """Returns the column matrix of generalized speeds""" + if self._speeds is None: + raise AttributeError("The speeds were not specified.") + else: + return self._speeds + + @property + def states(self): + """Returns the column matrix of the state variables""" + return self._states + + @property + def alg_con(self): + """Returns a list with the indices of the rows containing algebraic + constraints in the combined form of the equations of motion""" + return self._alg_con + + @property + def dyn_implicit_mat(self): + """Returns the matrix, M, corresponding to the dynamic equations in + implicit form, M x' = F, where the kinematical equations are not + included""" + if self._dyn_implicit_mat is None: + raise AttributeError("dyn_implicit_mat is not specified for " + "equations of motion form [1] or [2].") + else: + return self._dyn_implicit_mat + + @property + def dyn_implicit_rhs(self): + """Returns the column matrix, F, corresponding to the dynamic equations + in implicit form, M x' = F, where the kinematical equations are not + included""" + if self._dyn_implicit_rhs is None: + raise AttributeError("dyn_implicit_rhs is not specified for " + "equations of motion form [1] or [2].") + else: + return self._dyn_implicit_rhs + + @property + def comb_implicit_mat(self): + """Returns the matrix, M, corresponding to the equations of motion in + implicit form (form [2]), M x' = F, where the kinematical equations are + included""" + if self._comb_implicit_mat is None: + if self._dyn_implicit_mat is not None: + num_kin_eqns = len(self._kin_explicit_rhs) + num_dyn_eqns = len(self._dyn_implicit_rhs) + zeros1 = zeros(num_kin_eqns, num_dyn_eqns) + zeros2 = zeros(num_dyn_eqns, num_kin_eqns) + inter1 = eye(num_kin_eqns).row_join(zeros1) + inter2 = zeros2.row_join(self._dyn_implicit_mat) + self._comb_implicit_mat = inter1.col_join(inter2) + return self._comb_implicit_mat + else: + raise AttributeError("comb_implicit_mat is not specified for " + "equations of motion form [1].") + else: + return self._comb_implicit_mat + + @property + def comb_implicit_rhs(self): + """Returns the column matrix, F, corresponding to the equations of + motion in implicit form (form [2]), M x' = F, where the kinematical + equations are included""" + if self._comb_implicit_rhs is None: + if self._dyn_implicit_rhs is not None: + kin_inter = self._kin_explicit_rhs + dyn_inter = self._dyn_implicit_rhs + self._comb_implicit_rhs = kin_inter.col_join(dyn_inter) + return self._comb_implicit_rhs + else: + raise AttributeError("comb_implicit_mat is not specified for " + "equations of motion in form [1].") + else: + return self._comb_implicit_rhs + + def compute_explicit_form(self): + """If the explicit right hand side of the combined equations of motion + is to provided upon initialization, this method will calculate it. This + calculation can potentially take awhile to compute.""" + if self._comb_explicit_rhs is not None: + raise AttributeError("comb_explicit_rhs is already formed.") + + inter1 = getattr(self, 'kin_explicit_rhs', None) + if inter1 is not None: + inter2 = self._dyn_implicit_mat.LUsolve(self._dyn_implicit_rhs) + out = inter1.col_join(inter2) + else: + out = self._comb_implicit_mat.LUsolve(self._comb_implicit_rhs) + + self._comb_explicit_rhs = out + + @property + def comb_explicit_rhs(self): + """Returns the right hand side of the equations of motion in explicit + form, x' = F, where the kinematical equations are included""" + if self._comb_explicit_rhs is None: + raise AttributeError("Please run .combute_explicit_form before " + "attempting to access comb_explicit_rhs.") + else: + return self._comb_explicit_rhs + + @property + def kin_explicit_rhs(self): + """Returns the right hand side of the kinematical equations in explicit + form, q' = G""" + if self._kin_explicit_rhs is None: + raise AttributeError("kin_explicit_rhs is not specified for " + "equations of motion form [1] or [2].") + else: + return self._kin_explicit_rhs + + def dynamic_symbols(self): + """Returns a column matrix containing all of the symbols in the system + that depend on time""" + # Create a list of all of the expressions in the equations of motion + if self._comb_explicit_rhs is None: + eom_expressions = (self.comb_implicit_mat[:] + + self.comb_implicit_rhs[:]) + else: + eom_expressions = (self._comb_explicit_rhs[:]) + + functions_of_time = set() + for expr in eom_expressions: + functions_of_time = functions_of_time.union( + find_dynamicsymbols(expr)) + functions_of_time = functions_of_time.union(self._states) + + return tuple(functions_of_time) + + def constant_symbols(self): + """Returns a column matrix containing all of the symbols in the system + that do not depend on time""" + # Create a list of all of the expressions in the equations of motion + if self._comb_explicit_rhs is None: + eom_expressions = (self.comb_implicit_mat[:] + + self.comb_implicit_rhs[:]) + else: + eom_expressions = (self._comb_explicit_rhs[:]) + + constants = set() + for expr in eom_expressions: + constants = constants.union(expr.free_symbols) + constants.remove(dynamicsymbols._t) + + return tuple(constants) + + @property + def bodies(self): + """Returns the bodies in the system""" + if self._bodies is None: + raise AttributeError("bodies were not specified for the system.") + else: + return self._bodies + + @property + def loads(self): + """Returns the loads in the system""" + if self._loads is None: + raise AttributeError("loads were not specified for the system.") + else: + return self._loads diff --git a/lib/python3.12/site-packages/sympy/physics/mechanics/wrapping_geometry.py b/lib/python3.12/site-packages/sympy/physics/mechanics/wrapping_geometry.py new file mode 100644 index 0000000000000000000000000000000000000000..47ed3c1c463499b024afb9e31cfa2ecd77534132 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/mechanics/wrapping_geometry.py @@ -0,0 +1,641 @@ +"""Geometry objects for use by wrapping pathways.""" + +from abc import ABC, abstractmethod + +from sympy import Integer, acos, pi, sqrt, sympify, tan +from sympy.core.relational import Eq +from sympy.functions.elementary.trigonometric import atan2 +from sympy.polys.polytools import cancel +from sympy.physics.vector import Vector, dot +from sympy.simplify.simplify import trigsimp + + +__all__ = [ + 'WrappingGeometryBase', + 'WrappingCylinder', + 'WrappingSphere', +] + + +class WrappingGeometryBase(ABC): + """Abstract base class for all geometry classes to inherit from. + + Notes + ===== + + Instances of this class cannot be directly instantiated by users. However, + it can be used to created custom geometry types through subclassing. + + """ + + @property + @abstractmethod + def point(cls): + """The point with which the geometry is associated.""" + pass + + @abstractmethod + def point_on_surface(self, point): + """Returns ``True`` if a point is on the geometry's surface. + + Parameters + ========== + point : Point + The point for which it's to be ascertained if it's on the + geometry's surface or not. + + """ + pass + + @abstractmethod + def geodesic_length(self, point_1, point_2): + """Returns the shortest distance between two points on a geometry's + surface. + + Parameters + ========== + + point_1 : Point + The point from which the geodesic length should be calculated. + point_2 : Point + The point to which the geodesic length should be calculated. + + """ + pass + + @abstractmethod + def geodesic_end_vectors(self, point_1, point_2): + """The vectors parallel to the geodesic at the two end points. + + Parameters + ========== + + point_1 : Point + The point from which the geodesic originates. + point_2 : Point + The point at which the geodesic terminates. + + """ + pass + + def __repr__(self): + """Default representation of a geometry object.""" + return f'{self.__class__.__name__}()' + + +class WrappingSphere(WrappingGeometryBase): + """A solid spherical object. + + Explanation + =========== + + A wrapping geometry that allows for circular arcs to be defined between + pairs of points. These paths are always geodetic (the shortest possible). + + Examples + ======== + + To create a ``WrappingSphere`` instance, a ``Symbol`` denoting its radius + and ``Point`` at which its center will be located are needed: + + >>> from sympy import symbols + >>> from sympy.physics.mechanics import Point, WrappingSphere + >>> r = symbols('r') + >>> pO = Point('pO') + + A sphere with radius ``r`` centered on ``pO`` can be instantiated with: + + >>> WrappingSphere(r, pO) + WrappingSphere(radius=r, point=pO) + + Parameters + ========== + + radius : Symbol + Radius of the sphere. This symbol must represent a value that is + positive and constant, i.e. it cannot be a dynamic symbol, nor can it + be an expression. + point : Point + A point at which the sphere is centered. + + See Also + ======== + + WrappingCylinder: Cylindrical geometry where the wrapping direction can be + defined. + + """ + + def __init__(self, radius, point): + """Initializer for ``WrappingSphere``. + + Parameters + ========== + + radius : Symbol + The radius of the sphere. + point : Point + A point on which the sphere is centered. + + """ + self.radius = radius + self.point = point + + @property + def radius(self): + """Radius of the sphere.""" + return self._radius + + @radius.setter + def radius(self, radius): + self._radius = radius + + @property + def point(self): + """A point on which the sphere is centered.""" + return self._point + + @point.setter + def point(self, point): + self._point = point + + def point_on_surface(self, point): + """Returns ``True`` if a point is on the sphere's surface. + + Parameters + ========== + + point : Point + The point for which it's to be ascertained if it's on the sphere's + surface or not. This point's position relative to the sphere's + center must be a simple expression involving the radius of the + sphere, otherwise this check will likely not work. + + """ + point_vector = point.pos_from(self.point) + if isinstance(point_vector, Vector): + point_radius_squared = dot(point_vector, point_vector) + else: + point_radius_squared = point_vector**2 + return Eq(point_radius_squared, self.radius**2) == True + + def geodesic_length(self, point_1, point_2): + r"""Returns the shortest distance between two points on the sphere's + surface. + + Explanation + =========== + + The geodesic length, i.e. the shortest arc along the surface of a + sphere, connecting two points can be calculated using the formula: + + .. math:: + + l = \arccos\left(\mathbf{v}_1 \cdot \mathbf{v}_2\right) + + where $\mathbf{v}_1$ and $\mathbf{v}_2$ are the unit vectors from the + sphere's center to the first and second points on the sphere's surface + respectively. Note that the actual path that the geodesic will take is + undefined when the two points are directly opposite one another. + + Examples + ======== + + A geodesic length can only be calculated between two points on the + sphere's surface. Firstly, a ``WrappingSphere`` instance must be + created along with two points that will lie on its surface: + + >>> from sympy import symbols + >>> from sympy.physics.mechanics import (Point, ReferenceFrame, + ... WrappingSphere) + >>> N = ReferenceFrame('N') + >>> r = symbols('r') + >>> pO = Point('pO') + >>> pO.set_vel(N, 0) + >>> sphere = WrappingSphere(r, pO) + >>> p1 = Point('p1') + >>> p2 = Point('p2') + + Let's assume that ``p1`` lies at a distance of ``r`` in the ``N.x`` + direction from ``pO`` and that ``p2`` is located on the sphere's + surface in the ``N.y + N.z`` direction from ``pO``. These positions can + be set with: + + >>> p1.set_pos(pO, r*N.x) + >>> p1.pos_from(pO) + r*N.x + >>> p2.set_pos(pO, r*(N.y + N.z).normalize()) + >>> p2.pos_from(pO) + sqrt(2)*r/2*N.y + sqrt(2)*r/2*N.z + + The geodesic length, which is in this case is a quarter of the sphere's + circumference, can be calculated using the ``geodesic_length`` method: + + >>> sphere.geodesic_length(p1, p2) + pi*r/2 + + If the ``geodesic_length`` method is passed an argument, the ``Point`` + that doesn't lie on the sphere's surface then a ``ValueError`` is + raised because it's not possible to calculate a value in this case. + + Parameters + ========== + + point_1 : Point + Point from which the geodesic length should be calculated. + point_2 : Point + Point to which the geodesic length should be calculated. + + """ + for point in (point_1, point_2): + if not self.point_on_surface(point): + msg = ( + f'Geodesic length cannot be calculated as point {point} ' + f'with radius {point.pos_from(self.point).magnitude()} ' + f'from the sphere\'s center {self.point} does not lie on ' + f'the surface of {self} with radius {self.radius}.' + ) + raise ValueError(msg) + point_1_vector = point_1.pos_from(self.point).normalize() + point_2_vector = point_2.pos_from(self.point).normalize() + central_angle = acos(point_2_vector.dot(point_1_vector)) + geodesic_length = self.radius*central_angle + return geodesic_length + + def geodesic_end_vectors(self, point_1, point_2): + """The vectors parallel to the geodesic at the two end points. + + Parameters + ========== + + point_1 : Point + The point from which the geodesic originates. + point_2 : Point + The point at which the geodesic terminates. + + """ + pA, pB = point_1, point_2 + pO = self.point + pA_vec = pA.pos_from(pO) + pB_vec = pB.pos_from(pO) + + if pA_vec.cross(pB_vec) == 0: + msg = ( + f'Can\'t compute geodesic end vectors for the pair of points ' + f'{pA} and {pB} on a sphere {self} as they are diametrically ' + f'opposed, thus the geodesic is not defined.' + ) + raise ValueError(msg) + + return ( + pA_vec.cross(pB.pos_from(pA)).cross(pA_vec).normalize(), + pB_vec.cross(pA.pos_from(pB)).cross(pB_vec).normalize(), + ) + + def __repr__(self): + """Representation of a ``WrappingSphere``.""" + return ( + f'{self.__class__.__name__}(radius={self.radius}, ' + f'point={self.point})' + ) + + +class WrappingCylinder(WrappingGeometryBase): + """A solid (infinite) cylindrical object. + + Explanation + =========== + + A wrapping geometry that allows for circular arcs to be defined between + pairs of points. These paths are always geodetic (the shortest possible) in + the sense that they will be a straight line on the unwrapped cylinder's + surface. However, it is also possible for a direction to be specified, i.e. + paths can be influenced such that they either wrap along the shortest side + or the longest side of the cylinder. To define these directions, rotations + are in the positive direction following the right-hand rule. + + Examples + ======== + + To create a ``WrappingCylinder`` instance, a ``Symbol`` denoting its + radius, a ``Vector`` defining its axis, and a ``Point`` through which its + axis passes are needed: + + >>> from sympy import symbols + >>> from sympy.physics.mechanics import (Point, ReferenceFrame, + ... WrappingCylinder) + >>> N = ReferenceFrame('N') + >>> r = symbols('r') + >>> pO = Point('pO') + >>> ax = N.x + + A cylinder with radius ``r``, and axis parallel to ``N.x`` passing through + ``pO`` can be instantiated with: + + >>> WrappingCylinder(r, pO, ax) + WrappingCylinder(radius=r, point=pO, axis=N.x) + + Parameters + ========== + + radius : Symbol + The radius of the cylinder. + point : Point + A point through which the cylinder's axis passes. + axis : Vector + The axis along which the cylinder is aligned. + + See Also + ======== + + WrappingSphere: Spherical geometry where the wrapping direction is always + geodetic. + + """ + + def __init__(self, radius, point, axis): + """Initializer for ``WrappingCylinder``. + + Parameters + ========== + + radius : Symbol + The radius of the cylinder. This symbol must represent a value that + is positive and constant, i.e. it cannot be a dynamic symbol. + point : Point + A point through which the cylinder's axis passes. + axis : Vector + The axis along which the cylinder is aligned. + + """ + self.radius = radius + self.point = point + self.axis = axis + + @property + def radius(self): + """Radius of the cylinder.""" + return self._radius + + @radius.setter + def radius(self, radius): + self._radius = radius + + @property + def point(self): + """A point through which the cylinder's axis passes.""" + return self._point + + @point.setter + def point(self, point): + self._point = point + + @property + def axis(self): + """Axis along which the cylinder is aligned.""" + return self._axis + + @axis.setter + def axis(self, axis): + self._axis = axis.normalize() + + def point_on_surface(self, point): + """Returns ``True`` if a point is on the cylinder's surface. + + Parameters + ========== + + point : Point + The point for which it's to be ascertained if it's on the + cylinder's surface or not. This point's position relative to the + cylinder's axis must be a simple expression involving the radius of + the sphere, otherwise this check will likely not work. + + """ + relative_position = point.pos_from(self.point) + parallel = relative_position.dot(self.axis) * self.axis + point_vector = relative_position - parallel + if isinstance(point_vector, Vector): + point_radius_squared = dot(point_vector, point_vector) + else: + point_radius_squared = point_vector**2 + return Eq(trigsimp(point_radius_squared), self.radius**2) == True + + def geodesic_length(self, point_1, point_2): + """The shortest distance between two points on a geometry's surface. + + Explanation + =========== + + The geodesic length, i.e. the shortest arc along the surface of a + cylinder, connecting two points. It can be calculated using Pythagoras' + theorem. The first short side is the distance between the two points on + the cylinder's surface parallel to the cylinder's axis. The second + short side is the arc of a circle between the two points of the + cylinder's surface perpendicular to the cylinder's axis. The resulting + hypotenuse is the geodesic length. + + Examples + ======== + + A geodesic length can only be calculated between two points on the + cylinder's surface. Firstly, a ``WrappingCylinder`` instance must be + created along with two points that will lie on its surface: + + >>> from sympy import symbols, cos, sin + >>> from sympy.physics.mechanics import (Point, ReferenceFrame, + ... WrappingCylinder, dynamicsymbols) + >>> N = ReferenceFrame('N') + >>> r = symbols('r') + >>> pO = Point('pO') + >>> pO.set_vel(N, 0) + >>> cylinder = WrappingCylinder(r, pO, N.x) + >>> p1 = Point('p1') + >>> p2 = Point('p2') + + Let's assume that ``p1`` is located at ``N.x + r*N.y`` relative to + ``pO`` and that ``p2`` is located at ``r*(cos(q)*N.y + sin(q)*N.z)`` + relative to ``pO``, where ``q(t)`` is a generalized coordinate + specifying the angle rotated around the ``N.x`` axis according to the + right-hand rule where ``N.y`` is zero. These positions can be set with: + + >>> q = dynamicsymbols('q') + >>> p1.set_pos(pO, N.x + r*N.y) + >>> p1.pos_from(pO) + N.x + r*N.y + >>> p2.set_pos(pO, r*(cos(q)*N.y + sin(q)*N.z).normalize()) + >>> p2.pos_from(pO).simplify() + r*cos(q(t))*N.y + r*sin(q(t))*N.z + + The geodesic length, which is in this case a is the hypotenuse of a + right triangle where the other two side lengths are ``1`` (parallel to + the cylinder's axis) and ``r*q(t)`` (parallel to the cylinder's cross + section), can be calculated using the ``geodesic_length`` method: + + >>> cylinder.geodesic_length(p1, p2).simplify() + sqrt(r**2*q(t)**2 + 1) + + If the ``geodesic_length`` method is passed an argument ``Point`` that + doesn't lie on the sphere's surface then a ``ValueError`` is raised + because it's not possible to calculate a value in this case. + + Parameters + ========== + + point_1 : Point + Point from which the geodesic length should be calculated. + point_2 : Point + Point to which the geodesic length should be calculated. + + """ + for point in (point_1, point_2): + if not self.point_on_surface(point): + msg = ( + f'Geodesic length cannot be calculated as point {point} ' + f'with radius {point.pos_from(self.point).magnitude()} ' + f'from the cylinder\'s center {self.point} does not lie on ' + f'the surface of {self} with radius {self.radius} and axis ' + f'{self.axis}.' + ) + raise ValueError(msg) + + relative_position = point_2.pos_from(point_1) + parallel_length = relative_position.dot(self.axis) + + point_1_relative_position = point_1.pos_from(self.point) + point_1_perpendicular_vector = ( + point_1_relative_position + - point_1_relative_position.dot(self.axis)*self.axis + ).normalize() + + point_2_relative_position = point_2.pos_from(self.point) + point_2_perpendicular_vector = ( + point_2_relative_position + - point_2_relative_position.dot(self.axis)*self.axis + ).normalize() + + central_angle = _directional_atan( + cancel(point_1_perpendicular_vector + .cross(point_2_perpendicular_vector) + .dot(self.axis)), + cancel(point_1_perpendicular_vector.dot(point_2_perpendicular_vector)), + ) + + planar_arc_length = self.radius*central_angle + geodesic_length = sqrt(parallel_length**2 + planar_arc_length**2) + return geodesic_length + + def geodesic_end_vectors(self, point_1, point_2): + """The vectors parallel to the geodesic at the two end points. + + Parameters + ========== + + point_1 : Point + The point from which the geodesic originates. + point_2 : Point + The point at which the geodesic terminates. + + """ + point_1_from_origin_point = point_1.pos_from(self.point) + point_2_from_origin_point = point_2.pos_from(self.point) + + if point_1_from_origin_point == point_2_from_origin_point: + msg = ( + f'Cannot compute geodesic end vectors for coincident points ' + f'{point_1} and {point_2} as no geodesic exists.' + ) + raise ValueError(msg) + + point_1_parallel = point_1_from_origin_point.dot(self.axis) * self.axis + point_2_parallel = point_2_from_origin_point.dot(self.axis) * self.axis + point_1_normal = (point_1_from_origin_point - point_1_parallel) + point_2_normal = (point_2_from_origin_point - point_2_parallel) + + if point_1_normal == point_2_normal: + point_1_perpendicular = Vector(0) + point_2_perpendicular = Vector(0) + else: + point_1_perpendicular = self.axis.cross(point_1_normal).normalize() + point_2_perpendicular = -self.axis.cross(point_2_normal).normalize() + + geodesic_length = self.geodesic_length(point_1, point_2) + relative_position = point_2.pos_from(point_1) + parallel_length = relative_position.dot(self.axis) + planar_arc_length = sqrt(geodesic_length**2 - parallel_length**2) + + point_1_vector = ( + planar_arc_length * point_1_perpendicular + + parallel_length * self.axis + ).normalize() + point_2_vector = ( + planar_arc_length * point_2_perpendicular + - parallel_length * self.axis + ).normalize() + + return (point_1_vector, point_2_vector) + + def __repr__(self): + """Representation of a ``WrappingCylinder``.""" + return ( + f'{self.__class__.__name__}(radius={self.radius}, ' + f'point={self.point}, axis={self.axis})' + ) + + +def _directional_atan(numerator, denominator): + """Compute atan in a directional sense as required for geodesics. + + Explanation + =========== + + To be able to control the direction of the geodesic length along the + surface of a cylinder a dedicated arctangent function is needed that + properly handles the directionality of different case. This function + ensures that the central angle is always positive but shifting the case + where ``atan2`` would return a negative angle to be centered around + ``2*pi``. + + Notes + ===== + + This function only handles very specific cases, i.e. the ones that are + expected to be encountered when calculating symbolic geodesics on uniformly + curved surfaces. As such, ``NotImplemented`` errors can be raised in many + cases. This function is named with a leader underscore to indicate that it + only aims to provide very specific functionality within the private scope + of this module. + + """ + + if numerator.is_number and denominator.is_number: + angle = atan2(numerator, denominator) + if angle < 0: + angle += 2 * pi + elif numerator.is_number: + msg = ( + f'Cannot compute a directional atan when the numerator {numerator} ' + f'is numeric and the denominator {denominator} is symbolic.' + ) + raise NotImplementedError(msg) + elif denominator.is_number: + msg = ( + f'Cannot compute a directional atan when the numerator {numerator} ' + f'is symbolic and the denominator {denominator} is numeric.' + ) + raise NotImplementedError(msg) + else: + ratio = sympify(trigsimp(numerator / denominator)) + if isinstance(ratio, tan): + angle = ratio.args[0] + elif ( + ratio.is_Mul + and ratio.args[0] == Integer(-1) + and isinstance(ratio.args[1], tan) + ): + angle = 2 * pi - ratio.args[1].args[0] + else: + msg = f'Cannot 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-1, -1), (-1, 2, -1), (-1, -1, 2))) + assert pat_matrix(1, 1, 1, 1) == mat1 + assert pat_matrix(2, 1, 1, 1) == 2*mat1 + + # Second case, 1 in x, 0 in all others + mat2 = Matrix(((0, 0, 0), (0, 1, 0), (0, 0, 1))) + assert pat_matrix(1, 1, 0, 0) == mat2 + assert pat_matrix(2, 1, 0, 0) == 2*mat2 + + # Third case, 1 in y, 0 in all others + mat3 = Matrix(((1, 0, 0), (0, 0, 0), (0, 0, 1))) + assert pat_matrix(1, 0, 1, 0) == mat3 + assert pat_matrix(2, 0, 1, 0) == 2*mat3 + + # Fourth case, 1 in z, 0 in all others + mat4 = Matrix(((1, 0, 0), (0, 1, 0), (0, 0, 0))) + assert pat_matrix(1, 0, 0, 1) == mat4 + assert pat_matrix(2, 0, 0, 1) == 2*mat4 + + +def test_Pauli(): + #this and the following test are testing both Pauli and Dirac matrices + #and also that the general Matrix class works correctly in a real world + #situation + sigma1 = msigma(1) + sigma2 = msigma(2) + sigma3 = msigma(3) + + assert sigma1 == sigma1 + assert sigma1 != sigma2 + + # sigma*I -> I*sigma (see #354) + assert sigma1*sigma2 == sigma3*I + assert sigma3*sigma1 == sigma2*I + assert sigma2*sigma3 == sigma1*I + + assert sigma1*sigma1 == eye(2) + assert sigma2*sigma2 == eye(2) + assert sigma3*sigma3 == eye(2) + + assert sigma1*2*sigma1 == 2*eye(2) + assert sigma1*sigma3*sigma1 == -sigma3 + + +def test_Dirac(): + gamma0 = mgamma(0) + gamma1 = mgamma(1) + gamma2 = mgamma(2) + gamma3 = mgamma(3) + gamma5 = mgamma(5) + + # gamma*I -> I*gamma (see #354) + assert gamma5 == gamma0 * gamma1 * gamma2 * gamma3 * I + assert gamma1 * gamma2 + gamma2 * gamma1 == zeros(4) + assert gamma0 * gamma0 == eye(4) * minkowski_tensor[0, 0] + assert gamma2 * gamma2 != eye(4) * minkowski_tensor[0, 0] + assert gamma2 * gamma2 == eye(4) * minkowski_tensor[2, 2] + + assert mgamma(5, True) == \ + mgamma(0, True)*mgamma(1, True)*mgamma(2, True)*mgamma(3, True)*I + +def test_mdft(): + with warns_deprecated_sympy(): + assert mdft(1) == Matrix([[1]]) + with warns_deprecated_sympy(): + assert mdft(2) == 1/sqrt(2)*Matrix([[1,1],[1,-1]]) + with warns_deprecated_sympy(): + assert mdft(4) == Matrix([[S.Half, S.Half, S.Half, S.Half], + [S.Half, -I/2, Rational(-1,2), I/2], + [S.Half, Rational(-1,2), S.Half, Rational(-1,2)], + [S.Half, I/2, Rational(-1,2), -I/2]]) diff --git a/lib/python3.12/site-packages/sympy/physics/tests/test_secondquant.py b/lib/python3.12/site-packages/sympy/physics/tests/test_secondquant.py new file mode 100644 index 0000000000000000000000000000000000000000..dc9f4a499a7bee96d5fb5c76e83d84a72db5db8a --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/tests/test_secondquant.py @@ -0,0 +1,1280 @@ +from sympy.physics.secondquant import ( + Dagger, Bd, VarBosonicBasis, BBra, B, BKet, FixedBosonicBasis, + matrix_rep, apply_operators, InnerProduct, Commutator, KroneckerDelta, + AnnihilateBoson, CreateBoson, BosonicOperator, + F, Fd, FKet, BosonState, CreateFermion, AnnihilateFermion, + evaluate_deltas, AntiSymmetricTensor, contraction, NO, wicks, + PermutationOperator, simplify_index_permutations, + _sort_anticommuting_fermions, _get_ordered_dummies, + substitute_dummies, FockStateBosonKet, + ContractionAppliesOnlyToFermions +) + +from sympy.concrete.summations import Sum +from sympy.core.function import (Function, expand) +from sympy.core.numbers import (I, Rational) +from sympy.core.singleton import S +from sympy.core.symbol import (Dummy, Symbol, symbols) +from sympy.functions.elementary.miscellaneous import sqrt +from sympy.printing.repr import srepr +from sympy.simplify.simplify import simplify + +from sympy.testing.pytest import slow, raises +from sympy.printing.latex import latex + + +def test_PermutationOperator(): + p, q, r, s = symbols('p,q,r,s') + f, g, h, i = map(Function, 'fghi') + P = PermutationOperator + assert P(p, q).get_permuted(f(p)*g(q)) == -f(q)*g(p) + assert P(p, q).get_permuted(f(p, q)) == -f(q, p) + assert P(p, q).get_permuted(f(p)) == f(p) + expr = (f(p)*g(q)*h(r)*i(s) + - f(q)*g(p)*h(r)*i(s) + - f(p)*g(q)*h(s)*i(r) + + f(q)*g(p)*h(s)*i(r)) + perms = [P(p, q), P(r, s)] + assert (simplify_index_permutations(expr, perms) == + P(p, q)*P(r, s)*f(p)*g(q)*h(r)*i(s)) + assert latex(P(p, q)) == 'P(pq)' + + +def test_index_permutations_with_dummies(): + a, b, c, d = symbols('a b c d') + p, q, r, s = symbols('p q r s', cls=Dummy) + f, g = map(Function, 'fg') + P = PermutationOperator + + # No dummy substitution necessary + expr = f(a, b, p, q) - f(b, a, p, q) + assert simplify_index_permutations( + expr, [P(a, b)]) == P(a, b)*f(a, b, p, q) + + # Cases where dummy substitution is needed + expected = P(a, b)*substitute_dummies(f(a, b, p, q)) + + expr = f(a, b, p, q) - f(b, a, q, p) + result = simplify_index_permutations(expr, [P(a, b)]) + assert expected == substitute_dummies(result) + + expr = f(a, b, q, p) - f(b, a, p, q) + result = simplify_index_permutations(expr, [P(a, b)]) + assert expected == substitute_dummies(result) + + # A case where nothing can be done + expr = f(a, b, q, p) - g(b, a, p, q) + result = simplify_index_permutations(expr, [P(a, b)]) + assert expr == result + + +def test_dagger(): + i, j, n, m = symbols('i,j,n,m') + assert Dagger(1) == 1 + assert Dagger(1.0) == 1.0 + assert Dagger(2*I) == -2*I + assert Dagger(S.Half*I/3.0) == I*Rational(-1, 2)/3.0 + assert Dagger(BKet([n])) == BBra([n]) + assert Dagger(B(0)) == Bd(0) + assert Dagger(Bd(0)) == B(0) + assert Dagger(B(n)) == Bd(n) + assert Dagger(Bd(n)) == B(n) + assert Dagger(B(0) + B(1)) == Bd(0) + Bd(1) + assert Dagger(n*m) == Dagger(n)*Dagger(m) # n, m commute + assert Dagger(B(n)*B(m)) == Bd(m)*Bd(n) + assert Dagger(B(n)**10) == Dagger(B(n))**10 + assert Dagger('a') == Dagger(Symbol('a')) + assert Dagger(Dagger('a')) == Symbol('a') + + +def test_operator(): + i, j = symbols('i,j') + o = BosonicOperator(i) + assert o.state == i + assert o.is_symbolic + o = BosonicOperator(1) + assert o.state == 1 + assert not o.is_symbolic + + +def test_create(): + i, j, n, m = symbols('i,j,n,m') + o = Bd(i) + assert latex(o) == "{b^\\dagger_{i}}" + assert isinstance(o, CreateBoson) + o = o.subs(i, j) + assert o.atoms(Symbol) == {j} + o = Bd(0) + assert o.apply_operator(BKet([n])) == sqrt(n + 1)*BKet([n + 1]) + o = Bd(n) + assert o.apply_operator(BKet([n])) == o*BKet([n]) + + +def test_annihilate(): + i, j, n, m = symbols('i,j,n,m') + o = B(i) + assert latex(o) == "b_{i}" + assert isinstance(o, AnnihilateBoson) + o = o.subs(i, j) + assert o.atoms(Symbol) == {j} + o = B(0) + assert o.apply_operator(BKet([n])) == sqrt(n)*BKet([n - 1]) + o = B(n) + assert o.apply_operator(BKet([n])) == o*BKet([n]) + + +def test_basic_state(): + i, j, n, m = symbols('i,j,n,m') + s = BosonState([0, 1, 2, 3, 4]) + assert len(s) == 5 + assert s.args[0] == tuple(range(5)) + assert s.up(0) == BosonState([1, 1, 2, 3, 4]) + assert s.down(4) == BosonState([0, 1, 2, 3, 3]) + for i in range(5): + assert s.up(i).down(i) == s + assert s.down(0) == 0 + for i in range(5): + assert s[i] == i + s = BosonState([n, m]) + assert s.down(0) == BosonState([n - 1, m]) + assert s.up(0) == BosonState([n + 1, m]) + + +def test_basic_apply(): + n = symbols("n") + e = B(0)*BKet([n]) + assert apply_operators(e) == sqrt(n)*BKet([n - 1]) + e = Bd(0)*BKet([n]) + assert apply_operators(e) == sqrt(n + 1)*BKet([n + 1]) + + +def test_complex_apply(): + n, m = symbols("n,m") + o = Bd(0)*B(0)*Bd(1)*B(0) + e = apply_operators(o*BKet([n, m])) + answer = sqrt(n)*sqrt(m + 1)*(-1 + n)*BKet([-1 + n, 1 + m]) + assert expand(e) == expand(answer) + + +def test_number_operator(): + n = symbols("n") + o = Bd(0)*B(0) + e = apply_operators(o*BKet([n])) + assert e == n*BKet([n]) + + +def test_inner_product(): + i, j, k, l = symbols('i,j,k,l') + s1 = BBra([0]) + s2 = BKet([1]) + assert InnerProduct(s1, Dagger(s1)) == 1 + assert InnerProduct(s1, s2) == 0 + s1 = BBra([i, j]) + s2 = BKet([k, l]) + r = InnerProduct(s1, s2) + assert r == KroneckerDelta(i, k)*KroneckerDelta(j, l) + + +def test_symbolic_matrix_elements(): + n, m = symbols('n,m') + s1 = BBra([n]) + s2 = BKet([m]) + o = B(0) + e = apply_operators(s1*o*s2) + assert e == sqrt(m)*KroneckerDelta(n, m - 1) + + +def test_matrix_elements(): + b = VarBosonicBasis(5) + o = B(0) + m = matrix_rep(o, b) + for i in range(4): + assert m[i, i + 1] == sqrt(i + 1) + o = Bd(0) + m = matrix_rep(o, b) + for i in range(4): + assert m[i + 1, i] == sqrt(i + 1) + + +def test_fixed_bosonic_basis(): + b = FixedBosonicBasis(2, 2) + # assert b == [FockState((2, 0)), FockState((1, 1)), FockState((0, 2))] + state = b.state(1) + assert state == FockStateBosonKet((1, 1)) + assert b.index(state) == 1 + assert b.state(1) == b[1] + assert len(b) == 3 + assert str(b) == '[FockState((2, 0)), FockState((1, 1)), FockState((0, 2))]' + assert repr(b) == '[FockState((2, 0)), FockState((1, 1)), FockState((0, 2))]' + assert srepr(b) == '[FockState((2, 0)), FockState((1, 1)), FockState((0, 2))]' + + +@slow +def test_sho(): + n, m = symbols('n,m') + h_n = Bd(n)*B(n)*(n + S.Half) + H = Sum(h_n, (n, 0, 5)) + o = H.doit(deep=False) + b = FixedBosonicBasis(2, 6) + m = matrix_rep(o, b) + # We need to double check these energy values to make sure that they + # are correct and have the proper degeneracies! + diag = [1, 2, 3, 3, 4, 5, 4, 5, 6, 7, 5, 6, 7, 8, 9, 6, 7, 8, 9, 10, 11] + for i in range(len(diag)): + assert diag[i] == m[i, i] + + +def test_commutation(): + n, m = symbols("n,m", above_fermi=True) + c = Commutator(B(0), Bd(0)) + assert c == 1 + c = Commutator(Bd(0), B(0)) + assert c == -1 + c = Commutator(B(n), Bd(0)) + assert c == KroneckerDelta(n, 0) + c = Commutator(B(0), B(0)) + assert c == 0 + c = Commutator(B(0), Bd(0)) + e = simplify(apply_operators(c*BKet([n]))) + assert e == BKet([n]) + c = Commutator(B(0), B(1)) + e = simplify(apply_operators(c*BKet([n, m]))) + assert e == 0 + + c = Commutator(F(m), Fd(m)) + assert c == +1 - 2*NO(Fd(m)*F(m)) + c = Commutator(Fd(m), F(m)) + assert c.expand() == -1 + 2*NO(Fd(m)*F(m)) + + C = Commutator + X, Y, Z = symbols('X,Y,Z', commutative=False) + assert C(C(X, Y), Z) != 0 + assert C(C(X, Z), Y) != 0 + assert C(Y, C(X, Z)) != 0 + + i, j, k, l = symbols('i,j,k,l', below_fermi=True) + a, b, c, d = symbols('a,b,c,d', above_fermi=True) + p, q, r, s = symbols('p,q,r,s') + D = KroneckerDelta + + assert C(Fd(a), F(i)) == -2*NO(F(i)*Fd(a)) + assert C(Fd(j), NO(Fd(a)*F(i))).doit(wicks=True) == -D(j, i)*Fd(a) + assert C(Fd(a)*F(i), Fd(b)*F(j)).doit(wicks=True) == 0 + + c1 = Commutator(F(a), Fd(a)) + assert Commutator.eval(c1, c1) == 0 + c = Commutator(Fd(a)*F(i),Fd(b)*F(j)) + assert latex(c) == r'\left[{a^\dagger_{a}} a_{i},{a^\dagger_{b}} a_{j}\right]' + assert repr(c) == 'Commutator(CreateFermion(a)*AnnihilateFermion(i),CreateFermion(b)*AnnihilateFermion(j))' + assert str(c) == '[CreateFermion(a)*AnnihilateFermion(i),CreateFermion(b)*AnnihilateFermion(j)]' + + +def test_create_f(): + i, j, n, m = symbols('i,j,n,m') + o = Fd(i) + assert isinstance(o, CreateFermion) + o = o.subs(i, j) + assert o.atoms(Symbol) == {j} + o = Fd(1) + assert o.apply_operator(FKet([n])) == FKet([1, n]) + assert o.apply_operator(FKet([n])) == -FKet([n, 1]) + o = Fd(n) + assert o.apply_operator(FKet([])) == FKet([n]) + + vacuum = FKet([], fermi_level=4) + assert vacuum == FKet([], fermi_level=4) + + i, j, k, l = symbols('i,j,k,l', below_fermi=True) + a, b, c, d = symbols('a,b,c,d', above_fermi=True) + p, q, r, s = symbols('p,q,r,s') + + assert Fd(i).apply_operator(FKet([i, j, k], 4)) == FKet([j, k], 4) + assert Fd(a).apply_operator(FKet([i, b, k], 4)) == FKet([a, i, b, k], 4) + + assert Dagger(B(p)).apply_operator(q) == q*CreateBoson(p) + assert repr(Fd(p)) == 'CreateFermion(p)' + assert srepr(Fd(p)) == "CreateFermion(Symbol('p'))" + assert latex(Fd(p)) == r'{a^\dagger_{p}}' + + +def test_annihilate_f(): + i, j, n, m = symbols('i,j,n,m') + o = F(i) + assert isinstance(o, AnnihilateFermion) + o = o.subs(i, j) + assert o.atoms(Symbol) == {j} + o = F(1) + assert o.apply_operator(FKet([1, n])) == FKet([n]) + assert o.apply_operator(FKet([n, 1])) == -FKet([n]) + o = F(n) + assert o.apply_operator(FKet([n])) == FKet([]) + + i, j, k, l = symbols('i,j,k,l', below_fermi=True) + a, b, c, d = symbols('a,b,c,d', above_fermi=True) + p, q, r, s = symbols('p,q,r,s') + assert F(i).apply_operator(FKet([i, j, k], 4)) == 0 + assert F(a).apply_operator(FKet([i, b, k], 4)) == 0 + assert F(l).apply_operator(FKet([i, j, k], 3)) == 0 + assert F(l).apply_operator(FKet([i, j, k], 4)) == FKet([l, i, j, k], 4) + assert str(F(p)) == 'f(p)' + assert repr(F(p)) == 'AnnihilateFermion(p)' + assert srepr(F(p)) == "AnnihilateFermion(Symbol('p'))" + assert latex(F(p)) == 'a_{p}' + + +def test_create_b(): + i, j, n, m = symbols('i,j,n,m') + o = Bd(i) + assert isinstance(o, CreateBoson) + o = o.subs(i, j) + assert o.atoms(Symbol) == {j} + o = Bd(0) + assert o.apply_operator(BKet([n])) == sqrt(n + 1)*BKet([n + 1]) + o = Bd(n) + assert o.apply_operator(BKet([n])) == o*BKet([n]) + + +def test_annihilate_b(): + i, j, n, m = symbols('i,j,n,m') + o = B(i) + assert isinstance(o, AnnihilateBoson) + o = o.subs(i, j) + assert o.atoms(Symbol) == {j} + o = B(0) + + +def test_wicks(): + p, q, r, s = symbols('p,q,r,s', above_fermi=True) + + # Testing for particles only + + str = F(p)*Fd(q) + assert wicks(str) == NO(F(p)*Fd(q)) + KroneckerDelta(p, q) + str = Fd(p)*F(q) + assert wicks(str) == NO(Fd(p)*F(q)) + + str = F(p)*Fd(q)*F(r)*Fd(s) + nstr = wicks(str) + fasit = NO( + KroneckerDelta(p, q)*KroneckerDelta(r, s) + + KroneckerDelta(p, q)*AnnihilateFermion(r)*CreateFermion(s) + + KroneckerDelta(r, s)*AnnihilateFermion(p)*CreateFermion(q) + - KroneckerDelta(p, s)*AnnihilateFermion(r)*CreateFermion(q) + - AnnihilateFermion(p)*AnnihilateFermion(r)*CreateFermion(q)*CreateFermion(s)) + assert nstr == fasit + + assert (p*q*nstr).expand() == wicks(p*q*str) + assert (nstr*p*q*2).expand() == wicks(str*p*q*2) + + # Testing CC equations particles and holes + i, j, k, l = symbols('i j k l', below_fermi=True, cls=Dummy) + a, b, c, d = symbols('a b c d', above_fermi=True, cls=Dummy) + p, q, r, s = symbols('p q r s', cls=Dummy) + + assert (wicks(F(a)*NO(F(i)*F(j))*Fd(b)) == + NO(F(a)*F(i)*F(j)*Fd(b)) + + KroneckerDelta(a, b)*NO(F(i)*F(j))) + assert (wicks(F(a)*NO(F(i)*F(j)*F(k))*Fd(b)) == + NO(F(a)*F(i)*F(j)*F(k)*Fd(b)) - + KroneckerDelta(a, b)*NO(F(i)*F(j)*F(k))) + + expr = wicks(Fd(i)*NO(Fd(j)*F(k))*F(l)) + assert (expr == + -KroneckerDelta(i, k)*NO(Fd(j)*F(l)) - + KroneckerDelta(j, l)*NO(Fd(i)*F(k)) - + KroneckerDelta(i, k)*KroneckerDelta(j, l) + + KroneckerDelta(i, l)*NO(Fd(j)*F(k)) + + NO(Fd(i)*Fd(j)*F(k)*F(l))) + expr = wicks(F(a)*NO(F(b)*Fd(c))*Fd(d)) + assert (expr == + -KroneckerDelta(a, c)*NO(F(b)*Fd(d)) - + KroneckerDelta(b, d)*NO(F(a)*Fd(c)) - + KroneckerDelta(a, c)*KroneckerDelta(b, d) + + KroneckerDelta(a, d)*NO(F(b)*Fd(c)) + + NO(F(a)*F(b)*Fd(c)*Fd(d))) + + +def test_NO(): + i, j, k, l = symbols('i j k l', below_fermi=True) + a, b, c, d = symbols('a b c d', above_fermi=True) + p, q, r, s = symbols('p q r s', cls=Dummy) + + assert (NO(Fd(p)*F(q) + Fd(a)*F(b)) == + NO(Fd(p)*F(q)) + NO(Fd(a)*F(b))) + assert (NO(Fd(i)*NO(F(j)*Fd(a))) == + NO(Fd(i)*F(j)*Fd(a))) + assert NO(1) == 1 + assert NO(i) == i + assert (NO(Fd(a)*Fd(b)*(F(c) + F(d))) == + NO(Fd(a)*Fd(b)*F(c)) + + NO(Fd(a)*Fd(b)*F(d))) + + assert NO(Fd(a)*F(b))._remove_brackets() == Fd(a)*F(b) + assert NO(F(j)*Fd(i))._remove_brackets() == F(j)*Fd(i) + + assert (NO(Fd(p)*F(q)).subs(Fd(p), Fd(a) + Fd(i)) == + NO(Fd(a)*F(q)) + NO(Fd(i)*F(q))) + assert (NO(Fd(p)*F(q)).subs(F(q), F(a) + F(i)) == + NO(Fd(p)*F(a)) + NO(Fd(p)*F(i))) + + expr = NO(Fd(p)*F(q))._remove_brackets() + assert wicks(expr) == NO(expr) + + assert NO(Fd(a)*F(b)) == - NO(F(b)*Fd(a)) + + no = NO(Fd(a)*F(i)*F(b)*Fd(j)) + l1 = list(no.iter_q_creators()) + assert l1 == [0, 1] + l2 = list(no.iter_q_annihilators()) + assert l2 == [3, 2] + no = NO(Fd(a)*Fd(i)) + assert no.has_q_creators == 1 + assert no.has_q_annihilators == -1 + assert str(no) == ':CreateFermion(a)*CreateFermion(i):' + assert repr(no) == 'NO(CreateFermion(a)*CreateFermion(i))' + assert latex(no) == r'\left\{{a^\dagger_{a}} {a^\dagger_{i}}\right\}' + raises(NotImplementedError, lambda: NO(Bd(p)*F(q))) + + +def test_sorting(): + i, j = symbols('i,j', below_fermi=True) + a, b = symbols('a,b', above_fermi=True) + p, q = symbols('p,q') + + # p, q + assert _sort_anticommuting_fermions([Fd(p), F(q)]) == ([Fd(p), F(q)], 0) + assert _sort_anticommuting_fermions([F(p), Fd(q)]) == ([Fd(q), F(p)], 1) + + # i, p + assert _sort_anticommuting_fermions([F(p), Fd(i)]) == ([F(p), Fd(i)], 0) + assert _sort_anticommuting_fermions([Fd(i), F(p)]) == ([F(p), Fd(i)], 1) + assert _sort_anticommuting_fermions([Fd(p), Fd(i)]) == ([Fd(p), Fd(i)], 0) + assert _sort_anticommuting_fermions([Fd(i), Fd(p)]) == ([Fd(p), Fd(i)], 1) + assert _sort_anticommuting_fermions([F(p), F(i)]) == ([F(i), F(p)], 1) + assert _sort_anticommuting_fermions([F(i), F(p)]) == ([F(i), F(p)], 0) + assert _sort_anticommuting_fermions([Fd(p), F(i)]) == ([F(i), Fd(p)], 1) + assert _sort_anticommuting_fermions([F(i), Fd(p)]) == ([F(i), Fd(p)], 0) + + # a, p + assert _sort_anticommuting_fermions([F(p), Fd(a)]) == ([Fd(a), F(p)], 1) + assert _sort_anticommuting_fermions([Fd(a), F(p)]) == ([Fd(a), F(p)], 0) + assert _sort_anticommuting_fermions([Fd(p), Fd(a)]) == ([Fd(a), Fd(p)], 1) + assert _sort_anticommuting_fermions([Fd(a), Fd(p)]) == ([Fd(a), Fd(p)], 0) + assert _sort_anticommuting_fermions([F(p), F(a)]) == ([F(p), F(a)], 0) + assert _sort_anticommuting_fermions([F(a), F(p)]) == ([F(p), F(a)], 1) + assert _sort_anticommuting_fermions([Fd(p), F(a)]) == ([Fd(p), F(a)], 0) + assert _sort_anticommuting_fermions([F(a), Fd(p)]) == ([Fd(p), F(a)], 1) + + # i, a + assert _sort_anticommuting_fermions([F(i), Fd(j)]) == ([F(i), Fd(j)], 0) + assert _sort_anticommuting_fermions([Fd(j), F(i)]) == ([F(i), Fd(j)], 1) + assert _sort_anticommuting_fermions([Fd(a), Fd(i)]) == ([Fd(a), Fd(i)], 0) + assert _sort_anticommuting_fermions([Fd(i), Fd(a)]) == ([Fd(a), Fd(i)], 1) + assert _sort_anticommuting_fermions([F(a), F(i)]) == ([F(i), F(a)], 1) + assert _sort_anticommuting_fermions([F(i), F(a)]) == ([F(i), F(a)], 0) + + +def test_contraction(): + i, j, k, l = symbols('i,j,k,l', below_fermi=True) + a, b, c, d = symbols('a,b,c,d', above_fermi=True) + p, q, r, s = symbols('p,q,r,s') + assert contraction(Fd(i), F(j)) == KroneckerDelta(i, j) + assert contraction(F(a), Fd(b)) == KroneckerDelta(a, b) + assert contraction(F(a), Fd(i)) == 0 + assert contraction(Fd(a), F(i)) == 0 + assert contraction(F(i), Fd(a)) == 0 + assert contraction(Fd(i), F(a)) == 0 + assert contraction(Fd(i), F(p)) == KroneckerDelta(i, p) + restr = evaluate_deltas(contraction(Fd(p), F(q))) + assert restr.is_only_below_fermi + restr = evaluate_deltas(contraction(F(p), Fd(q))) + assert restr.is_only_above_fermi + raises(ContractionAppliesOnlyToFermions, lambda: contraction(B(a), Fd(b))) + + +def test_evaluate_deltas(): + i, j, k = symbols('i,j,k') + + r = KroneckerDelta(i, j) * KroneckerDelta(j, k) + assert evaluate_deltas(r) == KroneckerDelta(i, k) + + r = KroneckerDelta(i, 0) * KroneckerDelta(j, k) + assert evaluate_deltas(r) == KroneckerDelta(i, 0) * KroneckerDelta(j, k) + + r = KroneckerDelta(1, j) * KroneckerDelta(j, k) + assert evaluate_deltas(r) == KroneckerDelta(1, k) + + r = KroneckerDelta(j, 2) * KroneckerDelta(k, j) + assert evaluate_deltas(r) == KroneckerDelta(2, k) + + r = KroneckerDelta(i, 0) * KroneckerDelta(i, j) * KroneckerDelta(j, 1) + assert evaluate_deltas(r) == 0 + + r = (KroneckerDelta(0, i) * KroneckerDelta(0, j) + * KroneckerDelta(1, j) * KroneckerDelta(1, j)) + assert evaluate_deltas(r) == 0 + + +def test_Tensors(): + i, j, k, l = symbols('i j k l', below_fermi=True, cls=Dummy) + a, b, c, d = symbols('a b c d', above_fermi=True, cls=Dummy) + p, q, r, s = symbols('p q r s') + + AT = AntiSymmetricTensor + assert AT('t', (a, b), (i, j)) == -AT('t', (b, a), (i, j)) + assert AT('t', (a, b), (i, j)) == AT('t', (b, a), (j, i)) + assert AT('t', (a, b), (i, j)) == -AT('t', (a, b), (j, i)) + assert AT('t', (a, a), (i, j)) == 0 + assert AT('t', (a, b), (i, i)) == 0 + assert AT('t', (a, b, c), (i, j)) == -AT('t', (b, a, c), (i, j)) + assert AT('t', (a, b, c), (i, j, k)) == AT('t', (b, a, c), (i, k, j)) + + tabij = AT('t', (a, b), (i, j)) + assert tabij.has(a) + assert tabij.has(b) + assert tabij.has(i) + assert tabij.has(j) + assert tabij.subs(b, c) == AT('t', (a, c), (i, j)) + assert (2*tabij).subs(i, c) == 2*AT('t', (a, b), (c, j)) + assert tabij.symbol == Symbol('t') + assert latex(tabij) == '{t^{ab}_{ij}}' + assert str(tabij) == 't((_a, _b),(_i, _j))' + + assert AT('t', (a, a), (i, j)).subs(a, b) == AT('t', (b, b), (i, j)) + assert AT('t', (a, i), (a, j)).subs(a, b) == AT('t', (b, i), (b, j)) + + +def test_fully_contracted(): + i, j, k, l = symbols('i j k l', below_fermi=True) + a, b, c, d = symbols('a b c d', above_fermi=True) + p, q, r, s = symbols('p q r s', cls=Dummy) + + Fock = (AntiSymmetricTensor('f', (p,), (q,))* + NO(Fd(p)*F(q))) + V = (AntiSymmetricTensor('v', (p, q), (r, s))* + NO(Fd(p)*Fd(q)*F(s)*F(r)))/4 + + Fai = wicks(NO(Fd(i)*F(a))*Fock, + keep_only_fully_contracted=True, + simplify_kronecker_deltas=True) + assert Fai == AntiSymmetricTensor('f', (a,), (i,)) + Vabij = wicks(NO(Fd(i)*Fd(j)*F(b)*F(a))*V, + keep_only_fully_contracted=True, + simplify_kronecker_deltas=True) + assert Vabij == AntiSymmetricTensor('v', (a, b), (i, j)) + + +def test_substitute_dummies_without_dummies(): + i, j = symbols('i,j') + assert substitute_dummies(att(i, j) + 2) == att(i, j) + 2 + assert substitute_dummies(att(i, j) + 1) == att(i, j) + 1 + + +def test_substitute_dummies_NO_operator(): + i, j = symbols('i j', cls=Dummy) + assert substitute_dummies(att(i, j)*NO(Fd(i)*F(j)) + - att(j, i)*NO(Fd(j)*F(i))) == 0 + + +def test_substitute_dummies_SQ_operator(): + i, j = symbols('i j', cls=Dummy) + assert substitute_dummies(att(i, j)*Fd(i)*F(j) + - att(j, i)*Fd(j)*F(i)) == 0 + + +def test_substitute_dummies_new_indices(): + i, j = symbols('i j', below_fermi=True, cls=Dummy) + a, b = symbols('a b', above_fermi=True, cls=Dummy) + p, q = symbols('p q', cls=Dummy) + f = Function('f') + assert substitute_dummies(f(i, a, p) - f(j, b, q), new_indices=True) == 0 + + +def test_substitute_dummies_substitution_order(): + i, j, k, l = symbols('i j k l', below_fermi=True, cls=Dummy) + f = Function('f') + from sympy.utilities.iterables import variations + for permut in variations([i, j, k, l], 4): + assert substitute_dummies(f(*permut) - f(i, j, k, l)) == 0 + + +def test_dummy_order_inner_outer_lines_VT1T1T1(): + ii = symbols('i', below_fermi=True) + aa = symbols('a', above_fermi=True) + k, l = symbols('k l', below_fermi=True, cls=Dummy) + c, d = symbols('c d', above_fermi=True, cls=Dummy) + + v = Function('v') + t = Function('t') + dums = _get_ordered_dummies + + # Coupled-Cluster T1 terms with V*T1*T1*T1 + # t^{a}_{k} t^{c}_{i} t^{d}_{l} v^{lk}_{dc} + exprs = [ + # permut v and t <=> swapping internal lines, equivalent + # irrespective of symmetries in v + v(k, l, c, d)*t(c, ii)*t(d, l)*t(aa, k), + v(l, k, c, d)*t(c, ii)*t(d, k)*t(aa, l), + v(k, l, d, c)*t(d, ii)*t(c, l)*t(aa, k), + v(l, k, d, c)*t(d, ii)*t(c, k)*t(aa, l), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) != dums(permut) + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + + +def test_dummy_order_inner_outer_lines_VT1T1T1T1(): + ii, jj = symbols('i j', below_fermi=True) + aa, bb = symbols('a b', above_fermi=True) + k, l = symbols('k l', below_fermi=True, cls=Dummy) + c, d = symbols('c d', above_fermi=True, cls=Dummy) + + v = Function('v') + t = Function('t') + dums = _get_ordered_dummies + + # Coupled-Cluster T2 terms with V*T1*T1*T1*T1 + exprs = [ + # permut t <=> swapping external lines, not equivalent + # except if v has certain symmetries. + v(k, l, c, d)*t(c, ii)*t(d, jj)*t(aa, k)*t(bb, l), + v(k, l, c, d)*t(c, jj)*t(d, ii)*t(aa, k)*t(bb, l), + v(k, l, c, d)*t(c, ii)*t(d, jj)*t(bb, k)*t(aa, l), + v(k, l, c, d)*t(c, jj)*t(d, ii)*t(bb, k)*t(aa, l), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) != dums(permut) + assert substitute_dummies(exprs[0]) != substitute_dummies(permut) + exprs = [ + # permut v <=> swapping external lines, not equivalent + # except if v has certain symmetries. + # + # Note that in contrast to above, these permutations have identical + # dummy order. That is because the proximity to external indices + # has higher influence on the canonical dummy ordering than the + # position of a dummy on the factors. In fact, the terms here are + # similar in structure as the result of the dummy substitutions above. + v(k, l, c, d)*t(c, ii)*t(d, jj)*t(aa, k)*t(bb, l), + v(l, k, c, d)*t(c, ii)*t(d, jj)*t(aa, k)*t(bb, l), + v(k, l, d, c)*t(c, ii)*t(d, jj)*t(aa, k)*t(bb, l), + v(l, k, d, c)*t(c, ii)*t(d, jj)*t(aa, k)*t(bb, l), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) == dums(permut) + assert substitute_dummies(exprs[0]) != substitute_dummies(permut) + exprs = [ + # permut t and v <=> swapping internal lines, equivalent. + # Canonical dummy order is different, and a consistent + # substitution reveals the equivalence. + v(k, l, c, d)*t(c, ii)*t(d, jj)*t(aa, k)*t(bb, l), + v(k, l, d, c)*t(c, jj)*t(d, ii)*t(aa, k)*t(bb, l), + v(l, k, c, d)*t(c, ii)*t(d, jj)*t(bb, k)*t(aa, l), + v(l, k, d, c)*t(c, jj)*t(d, ii)*t(bb, k)*t(aa, l), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) != dums(permut) + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + + +def test_get_subNO(): + p, q, r = symbols('p,q,r') + assert NO(F(p)*F(q)*F(r)).get_subNO(1) == NO(F(p)*F(r)) + assert NO(F(p)*F(q)*F(r)).get_subNO(0) == NO(F(q)*F(r)) + assert NO(F(p)*F(q)*F(r)).get_subNO(2) == NO(F(p)*F(q)) + + +def test_equivalent_internal_lines_VT1T1(): + i, j, k, l = symbols('i j k l', below_fermi=True, cls=Dummy) + a, b, c, d = symbols('a b c d', above_fermi=True, cls=Dummy) + + v = Function('v') + t = Function('t') + dums = _get_ordered_dummies + + exprs = [ # permute v. Different dummy order. Not equivalent. + v(i, j, a, b)*t(a, i)*t(b, j), + v(j, i, a, b)*t(a, i)*t(b, j), + v(i, j, b, a)*t(a, i)*t(b, j), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) != dums(permut) + assert substitute_dummies(exprs[0]) != substitute_dummies(permut) + + exprs = [ # permute v. Different dummy order. Equivalent + v(i, j, a, b)*t(a, i)*t(b, j), + v(j, i, b, a)*t(a, i)*t(b, j), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) != dums(permut) + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + + exprs = [ # permute t. Same dummy order, not equivalent. + v(i, j, a, b)*t(a, i)*t(b, j), + v(i, j, a, b)*t(b, i)*t(a, j), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) == dums(permut) + assert substitute_dummies(exprs[0]) != substitute_dummies(permut) + + exprs = [ # permute v and t. Different dummy order, equivalent + v(i, j, a, b)*t(a, i)*t(b, j), + v(j, i, a, b)*t(a, j)*t(b, i), + v(i, j, b, a)*t(b, i)*t(a, j), + v(j, i, b, a)*t(b, j)*t(a, i), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) != dums(permut) + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + + +def test_equivalent_internal_lines_VT2conjT2(): + # this diagram requires special handling in TCE + i, j, k, l, m, n = symbols('i j k l m n', below_fermi=True, cls=Dummy) + a, b, c, d, e, f = symbols('a b c d e f', above_fermi=True, cls=Dummy) + p1, p2, p3, p4 = symbols('p1 p2 p3 p4', above_fermi=True, cls=Dummy) + h1, h2, h3, h4 = symbols('h1 h2 h3 h4', below_fermi=True, cls=Dummy) + + from sympy.utilities.iterables import variations + + v = Function('v') + t = Function('t') + dums = _get_ordered_dummies + + # v(abcd)t(abij)t(ijcd) + template = v(p1, p2, p3, p4)*t(p1, p2, i, j)*t(i, j, p3, p4) + permutator = variations([a, b, c, d], 4) + base = template.subs(zip([p1, p2, p3, p4], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4], permut) + expr = template.subs(subslist) + assert dums(base) != dums(expr) + assert substitute_dummies(expr) == substitute_dummies(base) + template = v(p1, p2, p3, p4)*t(p1, p2, j, i)*t(j, i, p3, p4) + permutator = variations([a, b, c, d], 4) + base = template.subs(zip([p1, p2, p3, p4], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4], permut) + expr = template.subs(subslist) + assert dums(base) != dums(expr) + assert substitute_dummies(expr) == substitute_dummies(base) + + # v(abcd)t(abij)t(jicd) + template = v(p1, p2, p3, p4)*t(p1, p2, i, j)*t(j, i, p3, p4) + permutator = variations([a, b, c, d], 4) + base = template.subs(zip([p1, p2, p3, p4], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4], permut) + expr = template.subs(subslist) + assert dums(base) != dums(expr) + assert substitute_dummies(expr) == substitute_dummies(base) + template = v(p1, p2, p3, p4)*t(p1, p2, j, i)*t(i, j, p3, p4) + permutator = variations([a, b, c, d], 4) + base = template.subs(zip([p1, p2, p3, p4], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4], permut) + expr = template.subs(subslist) + assert dums(base) != dums(expr) + assert substitute_dummies(expr) == substitute_dummies(base) + + +def test_equivalent_internal_lines_VT2conjT2_ambiguous_order(): + # These diagrams invokes _determine_ambiguous() because the + # dummies can not be ordered unambiguously by the key alone + i, j, k, l, m, n = symbols('i j k l m n', below_fermi=True, cls=Dummy) + a, b, c, d, e, f = symbols('a b c d e f', above_fermi=True, cls=Dummy) + p1, p2, p3, p4 = symbols('p1 p2 p3 p4', above_fermi=True, cls=Dummy) + h1, h2, h3, h4 = symbols('h1 h2 h3 h4', below_fermi=True, cls=Dummy) + + from sympy.utilities.iterables import variations + + v = Function('v') + t = Function('t') + dums = _get_ordered_dummies + + # v(abcd)t(abij)t(cdij) + template = v(p1, p2, p3, p4)*t(p1, p2, i, j)*t(p3, p4, i, j) + permutator = variations([a, b, c, d], 4) + base = template.subs(zip([p1, p2, p3, p4], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4], permut) + expr = template.subs(subslist) + assert dums(base) != dums(expr) + assert substitute_dummies(expr) == substitute_dummies(base) + template = v(p1, p2, p3, p4)*t(p1, p2, j, i)*t(p3, p4, i, j) + permutator = variations([a, b, c, d], 4) + base = template.subs(zip([p1, p2, p3, p4], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4], permut) + expr = template.subs(subslist) + assert dums(base) != dums(expr) + assert substitute_dummies(expr) == substitute_dummies(base) + + +def test_equivalent_internal_lines_VT2(): + i, j, k, l = symbols('i j k l', below_fermi=True, cls=Dummy) + a, b, c, d = symbols('a b c d', above_fermi=True, cls=Dummy) + + v = Function('v') + t = Function('t') + dums = _get_ordered_dummies + exprs = [ + # permute v. Same dummy order, not equivalent. + # + # This test show that the dummy order may not be sensitive to all + # index permutations. The following expressions have identical + # structure as the resulting terms from of the dummy substitutions + # in the test above. Here, all expressions have the same dummy + # order, so they cannot be simplified by means of dummy + # substitution. In order to simplify further, it is necessary to + # exploit symmetries in the objects, for instance if t or v is + # antisymmetric. + v(i, j, a, b)*t(a, b, i, j), + v(j, i, a, b)*t(a, b, i, j), + v(i, j, b, a)*t(a, b, i, j), + v(j, i, b, a)*t(a, b, i, j), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) == dums(permut) + assert substitute_dummies(exprs[0]) != substitute_dummies(permut) + + exprs = [ + # permute t. + v(i, j, a, b)*t(a, b, i, j), + v(i, j, a, b)*t(b, a, i, j), + v(i, j, a, b)*t(a, b, j, i), + v(i, j, a, b)*t(b, a, j, i), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) != dums(permut) + assert substitute_dummies(exprs[0]) != substitute_dummies(permut) + + exprs = [ # permute v and t. Relabelling of dummies should be equivalent. + v(i, j, a, b)*t(a, b, i, j), + v(j, i, a, b)*t(a, b, j, i), + v(i, j, b, a)*t(b, a, i, j), + v(j, i, b, a)*t(b, a, j, i), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) != dums(permut) + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + + +def test_internal_external_VT2T2(): + ii, jj = symbols('i j', below_fermi=True) + aa, bb = symbols('a b', above_fermi=True) + k, l = symbols('k l', below_fermi=True, cls=Dummy) + c, d = symbols('c d', above_fermi=True, cls=Dummy) + + v = Function('v') + t = Function('t') + dums = _get_ordered_dummies + + exprs = [ + v(k, l, c, d)*t(aa, c, ii, k)*t(bb, d, jj, l), + v(l, k, c, d)*t(aa, c, ii, l)*t(bb, d, jj, k), + v(k, l, d, c)*t(aa, d, ii, k)*t(bb, c, jj, l), + v(l, k, d, c)*t(aa, d, ii, l)*t(bb, c, jj, k), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) != dums(permut) + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + exprs = [ + v(k, l, c, d)*t(aa, c, ii, k)*t(d, bb, jj, l), + v(l, k, c, d)*t(aa, c, ii, l)*t(d, bb, jj, k), + v(k, l, d, c)*t(aa, d, ii, k)*t(c, bb, jj, l), + v(l, k, d, c)*t(aa, d, ii, l)*t(c, bb, jj, k), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) != dums(permut) + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + exprs = [ + v(k, l, c, d)*t(c, aa, ii, k)*t(bb, d, jj, l), + v(l, k, c, d)*t(c, aa, ii, l)*t(bb, d, jj, k), + v(k, l, d, c)*t(d, aa, ii, k)*t(bb, c, jj, l), + v(l, k, d, c)*t(d, aa, ii, l)*t(bb, c, jj, k), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) != dums(permut) + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + + +def test_internal_external_pqrs(): + ii, jj = symbols('i j') + aa, bb = symbols('a b') + k, l = symbols('k l', cls=Dummy) + c, d = symbols('c d', cls=Dummy) + + v = Function('v') + t = Function('t') + dums = _get_ordered_dummies + + exprs = [ + v(k, l, c, d)*t(aa, c, ii, k)*t(bb, d, jj, l), + v(l, k, c, d)*t(aa, c, ii, l)*t(bb, d, jj, k), + v(k, l, d, c)*t(aa, d, ii, k)*t(bb, c, jj, l), + v(l, k, d, c)*t(aa, d, ii, l)*t(bb, c, jj, k), + ] + for permut in exprs[1:]: + assert dums(exprs[0]) != dums(permut) + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + + +def test_dummy_order_well_defined(): + aa, bb = symbols('a b', above_fermi=True) + k, l, m = symbols('k l m', below_fermi=True, cls=Dummy) + c, d = symbols('c d', above_fermi=True, cls=Dummy) + p, q = symbols('p q', cls=Dummy) + + A = Function('A') + B = Function('B') + C = Function('C') + dums = _get_ordered_dummies + + # We go through all key components in the order of increasing priority, + # and consider only fully orderable expressions. Non-orderable expressions + # are tested elsewhere. + + # pos in first factor determines sort order + assert dums(A(k, l)*B(l, k)) == [k, l] + assert dums(A(l, k)*B(l, k)) == [l, k] + assert dums(A(k, l)*B(k, l)) == [k, l] + assert dums(A(l, k)*B(k, l)) == [l, k] + + # factors involving the index + assert dums(A(k, l)*B(l, m)*C(k, m)) == [l, k, m] + assert dums(A(k, l)*B(l, m)*C(m, k)) == [l, k, m] + assert dums(A(l, k)*B(l, m)*C(k, m)) == [l, k, m] + assert dums(A(l, k)*B(l, m)*C(m, k)) == [l, k, m] + assert dums(A(k, l)*B(m, l)*C(k, m)) == [l, k, m] + assert dums(A(k, l)*B(m, l)*C(m, k)) == [l, k, m] + assert dums(A(l, k)*B(m, l)*C(k, m)) == [l, k, m] + assert dums(A(l, k)*B(m, l)*C(m, k)) == [l, k, m] + + # same, but with factor order determined by non-dummies + assert dums(A(k, aa, l)*A(l, bb, m)*A(bb, k, m)) == [l, k, m] + assert dums(A(k, aa, l)*A(l, bb, m)*A(bb, m, k)) == [l, k, m] + assert dums(A(k, aa, l)*A(m, bb, l)*A(bb, k, m)) == [l, k, m] + assert dums(A(k, aa, l)*A(m, bb, l)*A(bb, m, k)) == [l, k, m] + assert dums(A(l, aa, k)*A(l, bb, m)*A(bb, k, m)) == [l, k, m] + assert dums(A(l, aa, k)*A(l, bb, m)*A(bb, m, k)) == [l, k, m] + assert dums(A(l, aa, k)*A(m, bb, l)*A(bb, k, m)) == [l, k, m] + assert dums(A(l, aa, k)*A(m, bb, l)*A(bb, m, k)) == [l, k, m] + + # index range + assert dums(A(p, c, k)*B(p, c, k)) == [k, c, p] + assert dums(A(p, k, c)*B(p, c, k)) == [k, c, p] + assert dums(A(c, k, p)*B(p, c, k)) == [k, c, p] + assert dums(A(c, p, k)*B(p, c, k)) == [k, c, p] + assert dums(A(k, c, p)*B(p, c, k)) == [k, c, p] + assert dums(A(k, p, c)*B(p, c, k)) == [k, c, p] + assert dums(B(p, c, k)*A(p, c, k)) == [k, c, p] + assert dums(B(p, k, c)*A(p, c, k)) == [k, c, p] + assert dums(B(c, k, p)*A(p, c, k)) == [k, c, p] + assert dums(B(c, p, k)*A(p, c, k)) == [k, c, p] + assert dums(B(k, c, p)*A(p, c, k)) == [k, c, p] + assert dums(B(k, p, c)*A(p, c, k)) == [k, c, p] + + +def test_dummy_order_ambiguous(): + aa, bb = symbols('a b', above_fermi=True) + i, j, k, l, m = symbols('i j k l m', below_fermi=True, cls=Dummy) + a, b, c, d, e = symbols('a b c d e', above_fermi=True, cls=Dummy) + p, q = symbols('p q', cls=Dummy) + p1, p2, p3, p4 = symbols('p1 p2 p3 p4', above_fermi=True, cls=Dummy) + p5, p6, p7, p8 = symbols('p5 p6 p7 p8', above_fermi=True, cls=Dummy) + h1, h2, h3, h4 = symbols('h1 h2 h3 h4', below_fermi=True, cls=Dummy) + h5, h6, h7, h8 = symbols('h5 h6 h7 h8', below_fermi=True, cls=Dummy) + + A = Function('A') + B = Function('B') + + from sympy.utilities.iterables import variations + + # A*A*A*A*B -- ordering of p5 and p4 is used to figure out the rest + template = A(p1, p2)*A(p4, p1)*A(p2, p3)*A(p3, p5)*B(p5, p4) + permutator = variations([a, b, c, d, e], 5) + base = template.subs(zip([p1, p2, p3, p4, p5], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4, p5], permut) + expr = template.subs(subslist) + assert substitute_dummies(expr) == substitute_dummies(base) + + # A*A*A*A*A -- an arbitrary index is assigned and the rest are figured out + template = A(p1, p2)*A(p4, p1)*A(p2, p3)*A(p3, p5)*A(p5, p4) + permutator = variations([a, b, c, d, e], 5) + base = template.subs(zip([p1, p2, p3, p4, p5], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4, p5], permut) + expr = template.subs(subslist) + assert substitute_dummies(expr) == substitute_dummies(base) + + # A*A*A -- ordering of p5 and p4 is used to figure out the rest + template = A(p1, p2, p4, p1)*A(p2, p3, p3, p5)*A(p5, p4) + permutator = variations([a, b, c, d, e], 5) + base = template.subs(zip([p1, p2, p3, p4, p5], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4, p5], permut) + expr = template.subs(subslist) + assert substitute_dummies(expr) == substitute_dummies(base) + + +def atv(*args): + return AntiSymmetricTensor('v', args[:2], args[2:] ) + + +def att(*args): + if len(args) == 4: + return AntiSymmetricTensor('t', args[:2], args[2:] ) + elif len(args) == 2: + return AntiSymmetricTensor('t', (args[0],), (args[1],)) + + +def test_dummy_order_inner_outer_lines_VT1T1T1_AT(): + ii = symbols('i', below_fermi=True) + aa = symbols('a', above_fermi=True) + k, l = symbols('k l', below_fermi=True, cls=Dummy) + c, d = symbols('c d', above_fermi=True, cls=Dummy) + + # Coupled-Cluster T1 terms with V*T1*T1*T1 + # t^{a}_{k} t^{c}_{i} t^{d}_{l} v^{lk}_{dc} + exprs = [ + # permut v and t <=> swapping internal lines, equivalent + # irrespective of symmetries in v + atv(k, l, c, d)*att(c, ii)*att(d, l)*att(aa, k), + atv(l, k, c, d)*att(c, ii)*att(d, k)*att(aa, l), + atv(k, l, d, c)*att(d, ii)*att(c, l)*att(aa, k), + atv(l, k, d, c)*att(d, ii)*att(c, k)*att(aa, l), + ] + for permut in exprs[1:]: + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + + +def test_dummy_order_inner_outer_lines_VT1T1T1T1_AT(): + ii, jj = symbols('i j', below_fermi=True) + aa, bb = symbols('a b', above_fermi=True) + k, l = symbols('k l', below_fermi=True, cls=Dummy) + c, d = symbols('c d', above_fermi=True, cls=Dummy) + + # Coupled-Cluster T2 terms with V*T1*T1*T1*T1 + # non-equivalent substitutions (change of sign) + exprs = [ + # permut t <=> swapping external lines + atv(k, l, c, d)*att(c, ii)*att(d, jj)*att(aa, k)*att(bb, l), + atv(k, l, c, d)*att(c, jj)*att(d, ii)*att(aa, k)*att(bb, l), + atv(k, l, c, d)*att(c, ii)*att(d, jj)*att(bb, k)*att(aa, l), + ] + for permut in exprs[1:]: + assert substitute_dummies(exprs[0]) == -substitute_dummies(permut) + + # equivalent substitutions + exprs = [ + atv(k, l, c, d)*att(c, ii)*att(d, jj)*att(aa, k)*att(bb, l), + # permut t <=> swapping external lines + atv(k, l, c, d)*att(c, jj)*att(d, ii)*att(bb, k)*att(aa, l), + ] + for permut in exprs[1:]: + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + + +def test_equivalent_internal_lines_VT1T1_AT(): + i, j, k, l = symbols('i j k l', below_fermi=True, cls=Dummy) + a, b, c, d = symbols('a b c d', above_fermi=True, cls=Dummy) + + exprs = [ # permute v. Different dummy order. Not equivalent. + atv(i, j, a, b)*att(a, i)*att(b, j), + atv(j, i, a, b)*att(a, i)*att(b, j), + atv(i, j, b, a)*att(a, i)*att(b, j), + ] + for permut in exprs[1:]: + assert substitute_dummies(exprs[0]) != substitute_dummies(permut) + + exprs = [ # permute v. Different dummy order. Equivalent + atv(i, j, a, b)*att(a, i)*att(b, j), + atv(j, i, b, a)*att(a, i)*att(b, j), + ] + for permut in exprs[1:]: + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + + exprs = [ # permute t. Same dummy order, not equivalent. + atv(i, j, a, b)*att(a, i)*att(b, j), + atv(i, j, a, b)*att(b, i)*att(a, j), + ] + for permut in exprs[1:]: + assert substitute_dummies(exprs[0]) != substitute_dummies(permut) + + exprs = [ # permute v and t. Different dummy order, equivalent + atv(i, j, a, b)*att(a, i)*att(b, j), + atv(j, i, a, b)*att(a, j)*att(b, i), + atv(i, j, b, a)*att(b, i)*att(a, j), + atv(j, i, b, a)*att(b, j)*att(a, i), + ] + for permut in exprs[1:]: + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + + +def test_equivalent_internal_lines_VT2conjT2_AT(): + # this diagram requires special handling in TCE + i, j, k, l, m, n = symbols('i j k l m n', below_fermi=True, cls=Dummy) + a, b, c, d, e, f = symbols('a b c d e f', above_fermi=True, cls=Dummy) + p1, p2, p3, p4 = symbols('p1 p2 p3 p4', above_fermi=True, cls=Dummy) + h1, h2, h3, h4 = symbols('h1 h2 h3 h4', below_fermi=True, cls=Dummy) + + from sympy.utilities.iterables import variations + + # atv(abcd)att(abij)att(ijcd) + template = atv(p1, p2, p3, p4)*att(p1, p2, i, j)*att(i, j, p3, p4) + permutator = variations([a, b, c, d], 4) + base = template.subs(zip([p1, p2, p3, p4], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4], permut) + expr = template.subs(subslist) + assert substitute_dummies(expr) == substitute_dummies(base) + template = atv(p1, p2, p3, p4)*att(p1, p2, j, i)*att(j, i, p3, p4) + permutator = variations([a, b, c, d], 4) + base = template.subs(zip([p1, p2, p3, p4], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4], permut) + expr = template.subs(subslist) + assert substitute_dummies(expr) == substitute_dummies(base) + + # atv(abcd)att(abij)att(jicd) + template = atv(p1, p2, p3, p4)*att(p1, p2, i, j)*att(j, i, p3, p4) + permutator = variations([a, b, c, d], 4) + base = template.subs(zip([p1, p2, p3, p4], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4], permut) + expr = template.subs(subslist) + assert substitute_dummies(expr) == substitute_dummies(base) + template = atv(p1, p2, p3, p4)*att(p1, p2, j, i)*att(i, j, p3, p4) + permutator = variations([a, b, c, d], 4) + base = template.subs(zip([p1, p2, p3, p4], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4], permut) + expr = template.subs(subslist) + assert substitute_dummies(expr) == substitute_dummies(base) + + +def test_equivalent_internal_lines_VT2conjT2_ambiguous_order_AT(): + # These diagrams invokes _determine_ambiguous() because the + # dummies can not be ordered unambiguously by the key alone + i, j, k, l, m, n = symbols('i j k l m n', below_fermi=True, cls=Dummy) + a, b, c, d, e, f = symbols('a b c d e f', above_fermi=True, cls=Dummy) + p1, p2, p3, p4 = symbols('p1 p2 p3 p4', above_fermi=True, cls=Dummy) + h1, h2, h3, h4 = symbols('h1 h2 h3 h4', below_fermi=True, cls=Dummy) + + from sympy.utilities.iterables import variations + + # atv(abcd)att(abij)att(cdij) + template = atv(p1, p2, p3, p4)*att(p1, p2, i, j)*att(p3, p4, i, j) + permutator = variations([a, b, c, d], 4) + base = template.subs(zip([p1, p2, p3, p4], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4], permut) + expr = template.subs(subslist) + assert substitute_dummies(expr) == substitute_dummies(base) + template = atv(p1, p2, p3, p4)*att(p1, p2, j, i)*att(p3, p4, i, j) + permutator = variations([a, b, c, d], 4) + base = template.subs(zip([p1, p2, p3, p4], next(permutator))) + for permut in permutator: + subslist = zip([p1, p2, p3, p4], permut) + expr = template.subs(subslist) + assert substitute_dummies(expr) == substitute_dummies(base) + + +def test_equivalent_internal_lines_VT2_AT(): + i, j, k, l = symbols('i j k l', below_fermi=True, cls=Dummy) + a, b, c, d = symbols('a b c d', above_fermi=True, cls=Dummy) + + exprs = [ + # permute v. Same dummy order, not equivalent. + atv(i, j, a, b)*att(a, b, i, j), + atv(j, i, a, b)*att(a, b, i, j), + atv(i, j, b, a)*att(a, b, i, j), + ] + for permut in exprs[1:]: + assert substitute_dummies(exprs[0]) != substitute_dummies(permut) + + exprs = [ + # permute t. + atv(i, j, a, b)*att(a, b, i, j), + atv(i, j, a, b)*att(b, a, i, j), + atv(i, j, a, b)*att(a, b, j, i), + ] + for permut in exprs[1:]: + assert substitute_dummies(exprs[0]) != substitute_dummies(permut) + + exprs = [ # permute v and t. Relabelling of dummies should be equivalent. + atv(i, j, a, b)*att(a, b, i, j), + atv(j, i, a, b)*att(a, b, j, i), + atv(i, j, b, a)*att(b, a, i, j), + atv(j, i, b, a)*att(b, a, j, i), + ] + for permut in exprs[1:]: + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + + +def test_internal_external_VT2T2_AT(): + ii, jj = symbols('i j', below_fermi=True) + aa, bb = symbols('a b', above_fermi=True) + k, l = symbols('k l', below_fermi=True, cls=Dummy) + c, d = symbols('c d', above_fermi=True, cls=Dummy) + + exprs = [ + atv(k, l, c, d)*att(aa, c, ii, k)*att(bb, d, jj, l), + atv(l, k, c, d)*att(aa, c, ii, l)*att(bb, d, jj, k), + atv(k, l, d, c)*att(aa, d, ii, k)*att(bb, c, jj, l), + atv(l, k, d, c)*att(aa, d, ii, l)*att(bb, c, jj, k), + ] + for permut in exprs[1:]: + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + exprs = [ + atv(k, l, c, d)*att(aa, c, ii, k)*att(d, bb, jj, l), + atv(l, k, c, d)*att(aa, c, ii, l)*att(d, bb, jj, k), + atv(k, l, d, c)*att(aa, d, ii, k)*att(c, bb, jj, l), + atv(l, k, d, c)*att(aa, d, ii, l)*att(c, bb, jj, k), + ] + for permut in exprs[1:]: + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + exprs = [ + atv(k, l, c, d)*att(c, aa, ii, k)*att(bb, d, jj, l), + atv(l, k, c, d)*att(c, aa, ii, l)*att(bb, d, jj, k), + atv(k, l, d, c)*att(d, aa, ii, k)*att(bb, c, jj, l), + atv(l, k, d, c)*att(d, aa, ii, l)*att(bb, c, jj, k), + ] + for permut in exprs[1:]: + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + + +def test_internal_external_pqrs_AT(): + ii, jj = symbols('i j') + aa, bb = symbols('a b') + k, l = symbols('k l', cls=Dummy) + c, d = symbols('c d', cls=Dummy) + + exprs = [ + atv(k, l, c, d)*att(aa, c, ii, k)*att(bb, d, jj, l), + atv(l, k, c, d)*att(aa, c, ii, l)*att(bb, d, jj, k), + atv(k, l, d, c)*att(aa, d, ii, k)*att(bb, c, jj, l), + atv(l, k, d, c)*att(aa, d, ii, l)*att(bb, c, jj, k), + ] + for permut in exprs[1:]: + assert substitute_dummies(exprs[0]) == substitute_dummies(permut) + + +def test_issue_19661(): + a = Symbol('0') + assert latex(Commutator(Bd(a)**2, B(a)) + ) == '- \\left[b_{0},{b^\\dagger_{0}}^{2}\\right]' + + +def test_canonical_ordering_AntiSymmetricTensor(): + v = symbols("v") + + c, d = symbols(('c','d'), above_fermi=True, + cls=Dummy) + k, l = symbols(('k','l'), below_fermi=True, + cls=Dummy) + + # formerly, the left gave either the left or the right + assert AntiSymmetricTensor(v, (k, l), (d, c) + ) == -AntiSymmetricTensor(v, (l, k), (d, c)) diff --git a/lib/python3.12/site-packages/sympy/physics/tests/test_sho.py b/lib/python3.12/site-packages/sympy/physics/tests/test_sho.py new file mode 100644 index 0000000000000000000000000000000000000000..7248838b4bb9ad280fd4211bbe208063b65adcf5 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/tests/test_sho.py @@ -0,0 +1,21 @@ +from sympy.core import symbols, Rational, Function, diff +from sympy.physics.sho import R_nl, E_nl +from sympy.simplify.simplify import simplify + + +def test_sho_R_nl(): + omega, r = symbols('omega r') + l = symbols('l', integer=True) + u = Function('u') + + # check that it obeys the Schrodinger equation + for n in range(5): + schreq = ( -diff(u(r), r, 2)/2 + ((l*(l + 1))/(2*r**2) + + omega**2*r**2/2 - E_nl(n, l, omega))*u(r) ) + result = schreq.subs(u(r), r*R_nl(n, l, omega/2, r)) + assert simplify(result.doit()) == 0 + + +def test_energy(): + n, l, hw = symbols('n l hw') + assert simplify(E_nl(n, l, hw) - (2*n + l + Rational(3, 2))*hw) == 0 diff --git a/lib/python3.12/site-packages/sympy/physics/units/__init__.py b/lib/python3.12/site-packages/sympy/physics/units/__init__.py new file mode 100644 index 0000000000000000000000000000000000000000..bf17c7f3051b03d9c0fc794d9d79885c94cc878e --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/__init__.py @@ -0,0 +1,453 @@ +# isort:skip_file +""" +Dimensional analysis and unit systems. + +This module defines dimension/unit systems and physical quantities. It is +based on a group-theoretical construction where dimensions are represented as +vectors (coefficients being the exponents), and units are defined as a dimension +to which we added a scale. + +Quantities are built from a factor and a unit, and are the basic objects that +one will use when doing computations. + +All objects except systems and prefixes can be used in SymPy expressions. +Note that as part of a CAS, various objects do not combine automatically +under operations. + +Details about the implementation can be found in the documentation, and we +will not repeat all the explanations we gave there concerning our approach. +Ideas about future developments can be found on the `Github wiki +`_, and you should consult +this page if you are willing to help. + +Useful functions: + +- ``find_unit``: easily lookup pre-defined units. +- ``convert_to(expr, newunit)``: converts an expression into the same + expression expressed in another unit. + +""" + +from .dimensions import Dimension, DimensionSystem +from .unitsystem import UnitSystem +from .util import convert_to +from .quantities import Quantity + +from .definitions.dimension_definitions import ( + amount_of_substance, acceleration, action, area, + capacitance, charge, conductance, current, energy, + force, frequency, impedance, inductance, length, + luminous_intensity, magnetic_density, + magnetic_flux, mass, momentum, power, pressure, temperature, time, + velocity, voltage, volume +) + +Unit = Quantity + +speed = velocity +luminosity = luminous_intensity +magnetic_flux_density = magnetic_density +amount = amount_of_substance + +from .prefixes import ( + # 10-power based: + yotta, + zetta, + exa, + peta, + tera, + giga, + mega, + kilo, + hecto, + deca, + deci, + centi, + milli, + micro, + nano, + pico, + femto, + atto, + zepto, + yocto, + # 2-power based: + kibi, + mebi, + gibi, + tebi, + pebi, + exbi, +) + +from .definitions import ( + percent, percents, + permille, + rad, radian, radians, + deg, degree, degrees, + sr, steradian, steradians, + mil, angular_mil, angular_mils, + m, meter, meters, + kg, kilogram, kilograms, + s, second, seconds, + A, ampere, amperes, + K, kelvin, kelvins, + mol, mole, moles, + cd, candela, candelas, + g, gram, grams, + mg, milligram, milligrams, + ug, microgram, micrograms, + t, tonne, metric_ton, + newton, newtons, N, + joule, joules, J, + watt, watts, W, + pascal, pascals, Pa, pa, + hertz, hz, Hz, + coulomb, coulombs, C, + volt, volts, v, V, + ohm, ohms, + siemens, S, mho, mhos, + farad, farads, F, + henry, henrys, H, + tesla, teslas, T, + weber, webers, Wb, wb, + optical_power, dioptre, D, + lux, lx, + katal, kat, + gray, Gy, + becquerel, Bq, + km, kilometer, kilometers, + dm, decimeter, decimeters, + cm, centimeter, centimeters, + mm, millimeter, millimeters, + um, micrometer, micrometers, micron, microns, + nm, nanometer, nanometers, + pm, picometer, picometers, + ft, foot, feet, + inch, inches, + yd, yard, yards, + mi, mile, miles, + nmi, nautical_mile, nautical_miles, + angstrom, angstroms, + ha, hectare, + l, L, liter, liters, + dl, dL, deciliter, deciliters, + cl, cL, centiliter, centiliters, + ml, mL, milliliter, milliliters, + ms, millisecond, milliseconds, + us, microsecond, microseconds, + ns, nanosecond, nanoseconds, + ps, picosecond, picoseconds, + minute, minutes, + h, hour, hours, + day, days, + anomalistic_year, anomalistic_years, + sidereal_year, sidereal_years, + tropical_year, tropical_years, + common_year, common_years, + julian_year, julian_years, + draconic_year, draconic_years, + gaussian_year, gaussian_years, + full_moon_cycle, full_moon_cycles, + year, years, + G, gravitational_constant, + c, speed_of_light, + elementary_charge, + hbar, + planck, + eV, electronvolt, electronvolts, + avogadro_number, + avogadro, avogadro_constant, + boltzmann, boltzmann_constant, + stefan, stefan_boltzmann_constant, + R, molar_gas_constant, + faraday_constant, + josephson_constant, + von_klitzing_constant, + Da, dalton, amu, amus, atomic_mass_unit, atomic_mass_constant, + me, electron_rest_mass, + gee, gees, acceleration_due_to_gravity, + u0, magnetic_constant, vacuum_permeability, + e0, electric_constant, vacuum_permittivity, + Z0, vacuum_impedance, + coulomb_constant, electric_force_constant, + atmosphere, atmospheres, atm, + kPa, + bar, bars, + pound, pounds, + psi, + dHg0, + mmHg, torr, + mmu, mmus, milli_mass_unit, + quart, quarts, + ly, lightyear, lightyears, + au, astronomical_unit, astronomical_units, + planck_mass, + planck_time, + planck_temperature, + planck_length, + planck_charge, + planck_area, + planck_volume, + planck_momentum, + planck_energy, + planck_force, + planck_power, + planck_density, + planck_energy_density, + planck_intensity, + planck_angular_frequency, + planck_pressure, + planck_current, + planck_voltage, + planck_impedance, + planck_acceleration, + bit, bits, + byte, + kibibyte, kibibytes, + mebibyte, mebibytes, + gibibyte, gibibytes, + tebibyte, tebibytes, + pebibyte, pebibytes, + exbibyte, exbibytes, +) + +from .systems import ( + mks, mksa, si +) + + +def find_unit(quantity, unit_system="SI"): + """ + Return a list of matching units or dimension names. + + - If ``quantity`` is a string -- units/dimensions containing the string + `quantity`. + - If ``quantity`` is a unit or dimension -- units having matching base + units or dimensions. + + Examples + ======== + + >>> from sympy.physics import units as u + >>> u.find_unit('charge') + ['C', 'coulomb', 'coulombs', 'planck_charge', 'elementary_charge'] + >>> u.find_unit(u.charge) + ['C', 'coulomb', 'coulombs', 'planck_charge', 'elementary_charge'] + >>> u.find_unit("ampere") + ['ampere', 'amperes'] + >>> u.find_unit('angstrom') + ['angstrom', 'angstroms'] + >>> u.find_unit('volt') + ['volt', 'volts', 'electronvolt', 'electronvolts', 'planck_voltage'] + >>> u.find_unit(u.inch**3)[:9] + ['L', 'l', 'cL', 'cl', 'dL', 'dl', 'mL', 'ml', 'liter'] + """ + unit_system = UnitSystem.get_unit_system(unit_system) + + import sympy.physics.units as u + rv = [] + if isinstance(quantity, str): + rv = [i for i in dir(u) if quantity in i and isinstance(getattr(u, i), Quantity)] + dim = getattr(u, quantity) + if isinstance(dim, Dimension): + rv.extend(find_unit(dim)) + else: + for i in sorted(dir(u)): + other = getattr(u, i) + if not isinstance(other, Quantity): + continue + if isinstance(quantity, Quantity): + if quantity.dimension == other.dimension: + rv.append(str(i)) + elif isinstance(quantity, Dimension): + if other.dimension == quantity: + rv.append(str(i)) + elif other.dimension == Dimension(unit_system.get_dimensional_expr(quantity)): + rv.append(str(i)) + return sorted(set(rv), key=lambda x: (len(x), x)) + +# NOTE: the old units module had additional variables: +# 'density', 'illuminance', 'resistance'. +# They were not dimensions, but units (old Unit class). + +__all__ = [ + 'Dimension', 'DimensionSystem', + 'UnitSystem', + 'convert_to', + 'Quantity', + + 'amount_of_substance', 'acceleration', 'action', 'area', + 'capacitance', 'charge', 'conductance', 'current', 'energy', + 'force', 'frequency', 'impedance', 'inductance', 'length', + 'luminous_intensity', 'magnetic_density', + 'magnetic_flux', 'mass', 'momentum', 'power', 'pressure', 'temperature', 'time', + 'velocity', 'voltage', 'volume', + + 'Unit', + + 'speed', + 'luminosity', + 'magnetic_flux_density', + 'amount', + + 'yotta', + 'zetta', + 'exa', + 'peta', + 'tera', + 'giga', + 'mega', + 'kilo', + 'hecto', + 'deca', + 'deci', + 'centi', + 'milli', + 'micro', + 'nano', + 'pico', + 'femto', + 'atto', + 'zepto', + 'yocto', + + 'kibi', + 'mebi', + 'gibi', + 'tebi', + 'pebi', + 'exbi', + + 'percent', 'percents', + 'permille', + 'rad', 'radian', 'radians', + 'deg', 'degree', 'degrees', + 'sr', 'steradian', 'steradians', + 'mil', 'angular_mil', 'angular_mils', + 'm', 'meter', 'meters', + 'kg', 'kilogram', 'kilograms', + 's', 'second', 'seconds', + 'A', 'ampere', 'amperes', + 'K', 'kelvin', 'kelvins', + 'mol', 'mole', 'moles', + 'cd', 'candela', 'candelas', + 'g', 'gram', 'grams', + 'mg', 'milligram', 'milligrams', + 'ug', 'microgram', 'micrograms', + 't', 'tonne', 'metric_ton', + 'newton', 'newtons', 'N', + 'joule', 'joules', 'J', + 'watt', 'watts', 'W', + 'pascal', 'pascals', 'Pa', 'pa', + 'hertz', 'hz', 'Hz', + 'coulomb', 'coulombs', 'C', + 'volt', 'volts', 'v', 'V', + 'ohm', 'ohms', + 'siemens', 'S', 'mho', 'mhos', + 'farad', 'farads', 'F', + 'henry', 'henrys', 'H', + 'tesla', 'teslas', 'T', + 'weber', 'webers', 'Wb', 'wb', + 'optical_power', 'dioptre', 'D', + 'lux', 'lx', + 'katal', 'kat', + 'gray', 'Gy', + 'becquerel', 'Bq', + 'km', 'kilometer', 'kilometers', + 'dm', 'decimeter', 'decimeters', + 'cm', 'centimeter', 'centimeters', + 'mm', 'millimeter', 'millimeters', + 'um', 'micrometer', 'micrometers', 'micron', 'microns', + 'nm', 'nanometer', 'nanometers', + 'pm', 'picometer', 'picometers', + 'ft', 'foot', 'feet', + 'inch', 'inches', + 'yd', 'yard', 'yards', + 'mi', 'mile', 'miles', + 'nmi', 'nautical_mile', 'nautical_miles', + 'angstrom', 'angstroms', + 'ha', 'hectare', + 'l', 'L', 'liter', 'liters', + 'dl', 'dL', 'deciliter', 'deciliters', + 'cl', 'cL', 'centiliter', 'centiliters', + 'ml', 'mL', 'milliliter', 'milliliters', + 'ms', 'millisecond', 'milliseconds', + 'us', 'microsecond', 'microseconds', + 'ns', 'nanosecond', 'nanoseconds', + 'ps', 'picosecond', 'picoseconds', + 'minute', 'minutes', + 'h', 'hour', 'hours', + 'day', 'days', + 'anomalistic_year', 'anomalistic_years', + 'sidereal_year', 'sidereal_years', + 'tropical_year', 'tropical_years', + 'common_year', 'common_years', + 'julian_year', 'julian_years', + 'draconic_year', 'draconic_years', + 'gaussian_year', 'gaussian_years', + 'full_moon_cycle', 'full_moon_cycles', + 'year', 'years', + 'G', 'gravitational_constant', + 'c', 'speed_of_light', + 'elementary_charge', + 'hbar', + 'planck', + 'eV', 'electronvolt', 'electronvolts', + 'avogadro_number', + 'avogadro', 'avogadro_constant', + 'boltzmann', 'boltzmann_constant', + 'stefan', 'stefan_boltzmann_constant', + 'R', 'molar_gas_constant', + 'faraday_constant', + 'josephson_constant', + 'von_klitzing_constant', + 'Da', 'dalton', 'amu', 'amus', 'atomic_mass_unit', 'atomic_mass_constant', + 'me', 'electron_rest_mass', + 'gee', 'gees', 'acceleration_due_to_gravity', + 'u0', 'magnetic_constant', 'vacuum_permeability', + 'e0', 'electric_constant', 'vacuum_permittivity', + 'Z0', 'vacuum_impedance', + 'coulomb_constant', 'electric_force_constant', + 'atmosphere', 'atmospheres', 'atm', + 'kPa', + 'bar', 'bars', + 'pound', 'pounds', + 'psi', + 'dHg0', + 'mmHg', 'torr', + 'mmu', 'mmus', 'milli_mass_unit', + 'quart', 'quarts', + 'ly', 'lightyear', 'lightyears', + 'au', 'astronomical_unit', 'astronomical_units', + 'planck_mass', + 'planck_time', + 'planck_temperature', + 'planck_length', + 'planck_charge', + 'planck_area', + 'planck_volume', + 'planck_momentum', + 'planck_energy', + 'planck_force', + 'planck_power', + 'planck_density', + 'planck_energy_density', + 'planck_intensity', + 'planck_angular_frequency', + 'planck_pressure', + 'planck_current', + 'planck_voltage', + 'planck_impedance', + 'planck_acceleration', + 'bit', 'bits', + 'byte', + 'kibibyte', 'kibibytes', + 'mebibyte', 'mebibytes', + 'gibibyte', 'gibibytes', + 'tebibyte', 'tebibytes', + 'pebibyte', 'pebibytes', + 'exbibyte', 'exbibytes', + + 'mks', 'mksa', 'si', +] diff --git a/lib/python3.12/site-packages/sympy/physics/units/__pycache__/__init__.cpython-312.pyc b/lib/python3.12/site-packages/sympy/physics/units/__pycache__/__init__.cpython-312.pyc new file mode 100644 index 0000000000000000000000000000000000000000..f62beff4dabe82f3e3ddd2fd847dc9646da1c6a7 Binary files /dev/null and b/lib/python3.12/site-packages/sympy/physics/units/__pycache__/__init__.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/units/__pycache__/dimensions.cpython-312.pyc 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b/lib/python3.12/site-packages/sympy/physics/units/__pycache__/util.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/units/definitions/__init__.py b/lib/python3.12/site-packages/sympy/physics/units/definitions/__init__.py new file mode 100644 index 0000000000000000000000000000000000000000..759889695d38c6e78237cc64974da3ecca6425cd --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/definitions/__init__.py @@ -0,0 +1,265 @@ +from .unit_definitions import ( + percent, percents, + permille, + rad, radian, radians, + deg, degree, degrees, + sr, steradian, steradians, + mil, angular_mil, angular_mils, + m, meter, meters, + kg, kilogram, kilograms, + s, second, seconds, + A, ampere, amperes, + K, kelvin, kelvins, + mol, mole, moles, + cd, candela, candelas, + g, gram, grams, + mg, milligram, milligrams, + ug, microgram, micrograms, + t, tonne, metric_ton, + newton, newtons, N, + joule, joules, J, + watt, watts, W, + pascal, pascals, Pa, pa, + hertz, hz, Hz, + coulomb, coulombs, C, + volt, volts, v, V, + ohm, ohms, + siemens, S, mho, mhos, + farad, farads, F, + henry, henrys, H, + tesla, teslas, T, + weber, webers, Wb, wb, + optical_power, dioptre, D, + lux, lx, + katal, kat, + gray, Gy, + becquerel, Bq, + km, kilometer, kilometers, + dm, decimeter, decimeters, + cm, centimeter, centimeters, + mm, millimeter, millimeters, + um, micrometer, micrometers, micron, microns, + nm, nanometer, nanometers, + pm, picometer, picometers, + ft, foot, feet, + inch, inches, + yd, yard, yards, + mi, mile, miles, + nmi, nautical_mile, nautical_miles, + ha, hectare, + l, L, liter, liters, + dl, dL, deciliter, deciliters, + cl, cL, centiliter, centiliters, + ml, mL, milliliter, milliliters, + ms, millisecond, milliseconds, + us, microsecond, microseconds, + ns, nanosecond, nanoseconds, + ps, picosecond, picoseconds, + minute, minutes, + h, hour, hours, + day, days, + anomalistic_year, anomalistic_years, + sidereal_year, sidereal_years, + tropical_year, tropical_years, + common_year, common_years, + julian_year, julian_years, + draconic_year, draconic_years, + gaussian_year, gaussian_years, + full_moon_cycle, full_moon_cycles, + year, years, + G, gravitational_constant, + c, speed_of_light, + elementary_charge, + hbar, + planck, + eV, electronvolt, electronvolts, + avogadro_number, + avogadro, avogadro_constant, + boltzmann, boltzmann_constant, + stefan, stefan_boltzmann_constant, + R, molar_gas_constant, + faraday_constant, + josephson_constant, + von_klitzing_constant, + Da, dalton, amu, amus, atomic_mass_unit, atomic_mass_constant, + me, electron_rest_mass, + gee, gees, acceleration_due_to_gravity, + u0, magnetic_constant, vacuum_permeability, + e0, electric_constant, vacuum_permittivity, + Z0, vacuum_impedance, + coulomb_constant, coulombs_constant, electric_force_constant, + atmosphere, atmospheres, atm, + kPa, kilopascal, + bar, bars, + pound, pounds, + psi, + dHg0, + mmHg, torr, + mmu, mmus, milli_mass_unit, + quart, quarts, + angstrom, angstroms, + ly, lightyear, lightyears, + au, astronomical_unit, astronomical_units, + planck_mass, + planck_time, + planck_temperature, + planck_length, + planck_charge, + planck_area, + planck_volume, + planck_momentum, + planck_energy, + planck_force, + planck_power, + planck_density, + planck_energy_density, + planck_intensity, + planck_angular_frequency, + planck_pressure, + planck_current, + planck_voltage, + planck_impedance, + planck_acceleration, + bit, bits, + byte, + kibibyte, kibibytes, + mebibyte, mebibytes, + gibibyte, gibibytes, + tebibyte, tebibytes, + pebibyte, pebibytes, + exbibyte, exbibytes, + curie, rutherford +) + +__all__ = [ + 'percent', 'percents', + 'permille', + 'rad', 'radian', 'radians', + 'deg', 'degree', 'degrees', + 'sr', 'steradian', 'steradians', + 'mil', 'angular_mil', 'angular_mils', + 'm', 'meter', 'meters', + 'kg', 'kilogram', 'kilograms', + 's', 'second', 'seconds', + 'A', 'ampere', 'amperes', + 'K', 'kelvin', 'kelvins', + 'mol', 'mole', 'moles', + 'cd', 'candela', 'candelas', + 'g', 'gram', 'grams', + 'mg', 'milligram', 'milligrams', + 'ug', 'microgram', 'micrograms', + 't', 'tonne', 'metric_ton', + 'newton', 'newtons', 'N', + 'joule', 'joules', 'J', + 'watt', 'watts', 'W', + 'pascal', 'pascals', 'Pa', 'pa', + 'hertz', 'hz', 'Hz', + 'coulomb', 'coulombs', 'C', + 'volt', 'volts', 'v', 'V', + 'ohm', 'ohms', + 'siemens', 'S', 'mho', 'mhos', + 'farad', 'farads', 'F', + 'henry', 'henrys', 'H', + 'tesla', 'teslas', 'T', + 'weber', 'webers', 'Wb', 'wb', + 'optical_power', 'dioptre', 'D', + 'lux', 'lx', + 'katal', 'kat', + 'gray', 'Gy', + 'becquerel', 'Bq', + 'km', 'kilometer', 'kilometers', + 'dm', 'decimeter', 'decimeters', + 'cm', 'centimeter', 'centimeters', + 'mm', 'millimeter', 'millimeters', + 'um', 'micrometer', 'micrometers', 'micron', 'microns', + 'nm', 'nanometer', 'nanometers', + 'pm', 'picometer', 'picometers', + 'ft', 'foot', 'feet', + 'inch', 'inches', + 'yd', 'yard', 'yards', + 'mi', 'mile', 'miles', + 'nmi', 'nautical_mile', 'nautical_miles', + 'ha', 'hectare', + 'l', 'L', 'liter', 'liters', + 'dl', 'dL', 'deciliter', 'deciliters', + 'cl', 'cL', 'centiliter', 'centiliters', + 'ml', 'mL', 'milliliter', 'milliliters', + 'ms', 'millisecond', 'milliseconds', + 'us', 'microsecond', 'microseconds', + 'ns', 'nanosecond', 'nanoseconds', + 'ps', 'picosecond', 'picoseconds', + 'minute', 'minutes', + 'h', 'hour', 'hours', + 'day', 'days', + 'anomalistic_year', 'anomalistic_years', + 'sidereal_year', 'sidereal_years', + 'tropical_year', 'tropical_years', + 'common_year', 'common_years', + 'julian_year', 'julian_years', + 'draconic_year', 'draconic_years', + 'gaussian_year', 'gaussian_years', + 'full_moon_cycle', 'full_moon_cycles', + 'year', 'years', + 'G', 'gravitational_constant', + 'c', 'speed_of_light', + 'elementary_charge', + 'hbar', + 'planck', + 'eV', 'electronvolt', 'electronvolts', + 'avogadro_number', + 'avogadro', 'avogadro_constant', + 'boltzmann', 'boltzmann_constant', + 'stefan', 'stefan_boltzmann_constant', + 'R', 'molar_gas_constant', + 'faraday_constant', + 'josephson_constant', + 'von_klitzing_constant', + 'Da', 'dalton', 'amu', 'amus', 'atomic_mass_unit', 'atomic_mass_constant', + 'me', 'electron_rest_mass', + 'gee', 'gees', 'acceleration_due_to_gravity', + 'u0', 'magnetic_constant', 'vacuum_permeability', + 'e0', 'electric_constant', 'vacuum_permittivity', + 'Z0', 'vacuum_impedance', + 'coulomb_constant', 'coulombs_constant', 'electric_force_constant', + 'atmosphere', 'atmospheres', 'atm', + 'kPa', 'kilopascal', + 'bar', 'bars', + 'pound', 'pounds', + 'psi', + 'dHg0', + 'mmHg', 'torr', + 'mmu', 'mmus', 'milli_mass_unit', + 'quart', 'quarts', + 'angstrom', 'angstroms', + 'ly', 'lightyear', 'lightyears', + 'au', 'astronomical_unit', 'astronomical_units', + 'planck_mass', + 'planck_time', + 'planck_temperature', + 'planck_length', + 'planck_charge', + 'planck_area', + 'planck_volume', + 'planck_momentum', + 'planck_energy', + 'planck_force', + 'planck_power', + 'planck_density', + 'planck_energy_density', + 'planck_intensity', + 'planck_angular_frequency', + 'planck_pressure', + 'planck_current', + 'planck_voltage', + 'planck_impedance', + 'planck_acceleration', + 'bit', 'bits', + 'byte', + 'kibibyte', 'kibibytes', + 'mebibyte', 'mebibytes', + 'gibibyte', 'gibibytes', + 'tebibyte', 'tebibytes', + 'pebibyte', 'pebibytes', + 'exbibyte', 'exbibytes', + 'curie', 'rutherford', +] diff --git a/lib/python3.12/site-packages/sympy/physics/units/definitions/__pycache__/__init__.cpython-312.pyc b/lib/python3.12/site-packages/sympy/physics/units/definitions/__pycache__/__init__.cpython-312.pyc new file mode 100644 index 0000000000000000000000000000000000000000..e1cc6baaf81324be64b04488029389921cabaa03 Binary files /dev/null and b/lib/python3.12/site-packages/sympy/physics/units/definitions/__pycache__/__init__.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/units/definitions/__pycache__/dimension_definitions.cpython-312.pyc b/lib/python3.12/site-packages/sympy/physics/units/definitions/__pycache__/dimension_definitions.cpython-312.pyc new file mode 100644 index 0000000000000000000000000000000000000000..d1147538cb5b2aa882a98b3c8f25e41034a3539d Binary files /dev/null and b/lib/python3.12/site-packages/sympy/physics/units/definitions/__pycache__/dimension_definitions.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/units/definitions/__pycache__/unit_definitions.cpython-312.pyc b/lib/python3.12/site-packages/sympy/physics/units/definitions/__pycache__/unit_definitions.cpython-312.pyc new file mode 100644 index 0000000000000000000000000000000000000000..3d32227d96e42980b1999921146ceb19e5e84b8c Binary files /dev/null and b/lib/python3.12/site-packages/sympy/physics/units/definitions/__pycache__/unit_definitions.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/units/definitions/dimension_definitions.py b/lib/python3.12/site-packages/sympy/physics/units/definitions/dimension_definitions.py new file mode 100644 index 0000000000000000000000000000000000000000..c9950d5855eea63f803cf42e68d944f18db90608 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/definitions/dimension_definitions.py @@ -0,0 +1,43 @@ +from sympy.physics.units import Dimension + + +angle = Dimension(name="angle") # type: Dimension + +# base dimensions (MKS) +length = Dimension(name="length", symbol="L") +mass = Dimension(name="mass", symbol="M") +time = Dimension(name="time", symbol="T") + +# base dimensions (MKSA not in MKS) +current = Dimension(name='current', symbol='I') # type: Dimension + +# other base dimensions: +temperature = Dimension("temperature", "T") # type: Dimension +amount_of_substance = Dimension("amount_of_substance") # type: Dimension +luminous_intensity = Dimension("luminous_intensity") # type: Dimension + +# derived dimensions (MKS) +velocity = Dimension(name="velocity") +acceleration = Dimension(name="acceleration") +momentum = Dimension(name="momentum") +force = Dimension(name="force", symbol="F") +energy = Dimension(name="energy", symbol="E") +power = Dimension(name="power") +pressure = Dimension(name="pressure") +frequency = Dimension(name="frequency", symbol="f") +action = Dimension(name="action", symbol="A") +area = Dimension("area") +volume = Dimension("volume") + +# derived dimensions (MKSA not in MKS) +voltage = Dimension(name='voltage', symbol='U') # type: Dimension +impedance = Dimension(name='impedance', symbol='Z') # type: Dimension +conductance = Dimension(name='conductance', symbol='G') # type: Dimension +capacitance = Dimension(name='capacitance') # type: Dimension +inductance = Dimension(name='inductance') # type: Dimension +charge = Dimension(name='charge', symbol='Q') # type: Dimension +magnetic_density = Dimension(name='magnetic_density', symbol='B') # type: Dimension +magnetic_flux = Dimension(name='magnetic_flux') # type: Dimension + +# Dimensions in information theory: +information = Dimension(name='information') # type: Dimension diff --git a/lib/python3.12/site-packages/sympy/physics/units/definitions/unit_definitions.py b/lib/python3.12/site-packages/sympy/physics/units/definitions/unit_definitions.py new file mode 100644 index 0000000000000000000000000000000000000000..c0a89802a444a40172a0dc70094321f07a7e396b --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/definitions/unit_definitions.py @@ -0,0 +1,407 @@ +from sympy.physics.units.definitions.dimension_definitions import current, temperature, amount_of_substance, \ + luminous_intensity, angle, charge, voltage, impedance, conductance, capacitance, inductance, magnetic_density, \ + magnetic_flux, information + +from sympy.core.numbers import (Rational, pi) +from sympy.core.singleton import S as S_singleton +from sympy.physics.units.prefixes import kilo, mega, milli, micro, deci, centi, nano, pico, kibi, mebi, gibi, tebi, pebi, exbi +from sympy.physics.units.quantities import PhysicalConstant, Quantity + +One = S_singleton.One + +#### UNITS #### + +# Dimensionless: +percent = percents = Quantity("percent", latex_repr=r"\%") +percent.set_global_relative_scale_factor(Rational(1, 100), One) + +permille = Quantity("permille") +permille.set_global_relative_scale_factor(Rational(1, 1000), One) + + +# Angular units (dimensionless) +rad = radian = radians = Quantity("radian", abbrev="rad") +radian.set_global_dimension(angle) +deg = degree = degrees = Quantity("degree", abbrev="deg", latex_repr=r"^\circ") +degree.set_global_relative_scale_factor(pi/180, radian) +sr = steradian = steradians = Quantity("steradian", abbrev="sr") +mil = angular_mil = angular_mils = Quantity("angular_mil", abbrev="mil") + +# Base units: +m = meter = meters = Quantity("meter", abbrev="m") + +# gram; used to define its prefixed units +g = gram = grams = Quantity("gram", abbrev="g") + +# NOTE: the `kilogram` has scale factor 1000. In SI, kg is a base unit, but +# nonetheless we are trying to be compatible with the `kilo` prefix. In a +# similar manner, people using CGS or gaussian units could argue that the +# `centimeter` rather than `meter` is the fundamental unit for length, but the +# scale factor of `centimeter` will be kept as 1/100 to be compatible with the +# `centi` prefix. The current state of the code assumes SI unit dimensions, in +# the future this module will be modified in order to be unit system-neutral +# (that is, support all kinds of unit systems). +kg = kilogram = kilograms = Quantity("kilogram", abbrev="kg") +kg.set_global_relative_scale_factor(kilo, gram) + +s = second = seconds = Quantity("second", abbrev="s") +A = ampere = amperes = Quantity("ampere", abbrev='A') +ampere.set_global_dimension(current) +K = kelvin = kelvins = Quantity("kelvin", abbrev='K') +kelvin.set_global_dimension(temperature) +mol = mole = moles = Quantity("mole", abbrev="mol") +mole.set_global_dimension(amount_of_substance) +cd = candela = candelas = Quantity("candela", abbrev="cd") +candela.set_global_dimension(luminous_intensity) + +# derived units +newton = newtons = N = Quantity("newton", abbrev="N") + +kilonewton = kilonewtons = kN = Quantity("kilonewton", abbrev="kN") +kilonewton.set_global_relative_scale_factor(kilo, newton) + +meganewton = meganewtons = MN = Quantity("meganewton", abbrev="MN") +meganewton.set_global_relative_scale_factor(mega, newton) + +joule = joules = J = Quantity("joule", abbrev="J") +watt = watts = W = Quantity("watt", abbrev="W") +pascal = pascals = Pa = pa = Quantity("pascal", abbrev="Pa") +hertz = hz = Hz = Quantity("hertz", abbrev="Hz") + +# CGS derived units: +dyne = Quantity("dyne") +dyne.set_global_relative_scale_factor(One/10**5, newton) +erg = Quantity("erg") +erg.set_global_relative_scale_factor(One/10**7, joule) + +# MKSA extension to MKS: derived units +coulomb = coulombs = C = Quantity("coulomb", abbrev='C') +coulomb.set_global_dimension(charge) +volt = volts = v = V = Quantity("volt", abbrev='V') +volt.set_global_dimension(voltage) +ohm = ohms = Quantity("ohm", abbrev='ohm', latex_repr=r"\Omega") +ohm.set_global_dimension(impedance) +siemens = S = mho = mhos = Quantity("siemens", abbrev='S') +siemens.set_global_dimension(conductance) +farad = farads = F = Quantity("farad", abbrev='F') +farad.set_global_dimension(capacitance) +henry = henrys = H = Quantity("henry", abbrev='H') +henry.set_global_dimension(inductance) +tesla = teslas = T = Quantity("tesla", abbrev='T') +tesla.set_global_dimension(magnetic_density) +weber = webers = Wb = wb = Quantity("weber", abbrev='Wb') +weber.set_global_dimension(magnetic_flux) + +# CGS units for electromagnetic quantities: +statampere = Quantity("statampere") +statcoulomb = statC = franklin = Quantity("statcoulomb", abbrev="statC") +statvolt = Quantity("statvolt") +gauss = Quantity("gauss") +maxwell = Quantity("maxwell") +debye = Quantity("debye") +oersted = Quantity("oersted") + +# Other derived units: +optical_power = dioptre = diopter = D = Quantity("dioptre") +lux = lx = Quantity("lux", abbrev="lx") + +# katal is the SI unit of catalytic activity +katal = kat = Quantity("katal", abbrev="kat") + +# gray is the SI unit of absorbed dose +gray = Gy = Quantity("gray") + +# becquerel is the SI unit of radioactivity +becquerel = Bq = Quantity("becquerel", abbrev="Bq") + + +# Common mass units + +mg = milligram = milligrams = Quantity("milligram", abbrev="mg") +mg.set_global_relative_scale_factor(milli, gram) + +ug = microgram = micrograms = Quantity("microgram", abbrev="ug", latex_repr=r"\mu\text{g}") +ug.set_global_relative_scale_factor(micro, gram) + +# Atomic mass constant +Da = dalton = amu = amus = atomic_mass_unit = atomic_mass_constant = PhysicalConstant("atomic_mass_constant") + +t = metric_ton = tonne = Quantity("tonne", abbrev="t") +tonne.set_global_relative_scale_factor(mega, gram) + +# Electron rest mass +me = electron_rest_mass = Quantity("electron_rest_mass", abbrev="me") + + +# Common length units + +km = kilometer = kilometers = Quantity("kilometer", abbrev="km") +km.set_global_relative_scale_factor(kilo, meter) + +dm = decimeter = decimeters = Quantity("decimeter", abbrev="dm") +dm.set_global_relative_scale_factor(deci, meter) + +cm = centimeter = centimeters = Quantity("centimeter", abbrev="cm") +cm.set_global_relative_scale_factor(centi, meter) + +mm = millimeter = millimeters = Quantity("millimeter", abbrev="mm") +mm.set_global_relative_scale_factor(milli, meter) + +um = micrometer = micrometers = micron = microns = \ + Quantity("micrometer", abbrev="um", latex_repr=r'\mu\text{m}') +um.set_global_relative_scale_factor(micro, meter) + +nm = nanometer = nanometers = Quantity("nanometer", abbrev="nm") +nm.set_global_relative_scale_factor(nano, meter) + +pm = picometer = picometers = Quantity("picometer", abbrev="pm") +pm.set_global_relative_scale_factor(pico, meter) + +ft = foot = feet = Quantity("foot", abbrev="ft") +ft.set_global_relative_scale_factor(Rational(3048, 10000), meter) + +inch = inches = Quantity("inch") +inch.set_global_relative_scale_factor(Rational(1, 12), foot) + +yd = yard = yards = Quantity("yard", abbrev="yd") +yd.set_global_relative_scale_factor(3, feet) + +mi = mile = miles = Quantity("mile") +mi.set_global_relative_scale_factor(5280, feet) + +nmi = nautical_mile = nautical_miles = Quantity("nautical_mile") +nmi.set_global_relative_scale_factor(6076, feet) + +angstrom = angstroms = Quantity("angstrom", latex_repr=r'\r{A}') +angstrom.set_global_relative_scale_factor(Rational(1, 10**10), meter) + + +# Common volume and area units + +ha = hectare = Quantity("hectare", abbrev="ha") + +l = L = liter = liters = Quantity("liter", abbrev="l") + +dl = dL = deciliter = deciliters = Quantity("deciliter", abbrev="dl") +dl.set_global_relative_scale_factor(Rational(1, 10), liter) + +cl = cL = centiliter = centiliters = Quantity("centiliter", abbrev="cl") +cl.set_global_relative_scale_factor(Rational(1, 100), liter) + +ml = mL = milliliter = milliliters = Quantity("milliliter", abbrev="ml") +ml.set_global_relative_scale_factor(Rational(1, 1000), liter) + + +# Common time units + +ms = millisecond = milliseconds = Quantity("millisecond", abbrev="ms") +millisecond.set_global_relative_scale_factor(milli, second) + +us = microsecond = microseconds = Quantity("microsecond", abbrev="us", latex_repr=r'\mu\text{s}') +microsecond.set_global_relative_scale_factor(micro, second) + +ns = nanosecond = nanoseconds = Quantity("nanosecond", abbrev="ns") +nanosecond.set_global_relative_scale_factor(nano, second) + +ps = picosecond = picoseconds = Quantity("picosecond", abbrev="ps") +picosecond.set_global_relative_scale_factor(pico, second) + +minute = minutes = Quantity("minute") +minute.set_global_relative_scale_factor(60, second) + +h = hour = hours = Quantity("hour") +hour.set_global_relative_scale_factor(60, minute) + +day = days = Quantity("day") +day.set_global_relative_scale_factor(24, hour) + +anomalistic_year = anomalistic_years = Quantity("anomalistic_year") +anomalistic_year.set_global_relative_scale_factor(365.259636, day) + +sidereal_year = sidereal_years = Quantity("sidereal_year") +sidereal_year.set_global_relative_scale_factor(31558149.540, seconds) + +tropical_year = tropical_years = Quantity("tropical_year") +tropical_year.set_global_relative_scale_factor(365.24219, day) + +common_year = common_years = Quantity("common_year") +common_year.set_global_relative_scale_factor(365, day) + +julian_year = julian_years = Quantity("julian_year") +julian_year.set_global_relative_scale_factor((365 + One/4), day) + +draconic_year = draconic_years = Quantity("draconic_year") +draconic_year.set_global_relative_scale_factor(346.62, day) + +gaussian_year = gaussian_years = Quantity("gaussian_year") +gaussian_year.set_global_relative_scale_factor(365.2568983, day) + +full_moon_cycle = full_moon_cycles = Quantity("full_moon_cycle") +full_moon_cycle.set_global_relative_scale_factor(411.78443029, day) + +year = years = tropical_year + + +#### CONSTANTS #### + +# Newton constant +G = gravitational_constant = PhysicalConstant("gravitational_constant", abbrev="G") + +# speed of light +c = speed_of_light = PhysicalConstant("speed_of_light", abbrev="c") + +# elementary charge +elementary_charge = PhysicalConstant("elementary_charge", abbrev="e") + +# Planck constant +planck = PhysicalConstant("planck", abbrev="h") + +# Reduced Planck constant +hbar = PhysicalConstant("hbar", abbrev="hbar") + +# Electronvolt +eV = electronvolt = electronvolts = PhysicalConstant("electronvolt", abbrev="eV") + +# Avogadro number +avogadro_number = PhysicalConstant("avogadro_number") + +# Avogadro constant +avogadro = avogadro_constant = PhysicalConstant("avogadro_constant") + +# Boltzmann constant +boltzmann = boltzmann_constant = PhysicalConstant("boltzmann_constant") + +# Stefan-Boltzmann constant +stefan = stefan_boltzmann_constant = PhysicalConstant("stefan_boltzmann_constant") + +# Molar gas constant +R = molar_gas_constant = PhysicalConstant("molar_gas_constant", abbrev="R") + +# Faraday constant +faraday_constant = PhysicalConstant("faraday_constant") + +# Josephson constant +josephson_constant = PhysicalConstant("josephson_constant", abbrev="K_j") + +# Von Klitzing constant +von_klitzing_constant = PhysicalConstant("von_klitzing_constant", abbrev="R_k") + +# Acceleration due to gravity (on the Earth surface) +gee = gees = acceleration_due_to_gravity = PhysicalConstant("acceleration_due_to_gravity", abbrev="g") + +# magnetic constant: +u0 = magnetic_constant = vacuum_permeability = PhysicalConstant("magnetic_constant") + +# electric constat: +e0 = electric_constant = vacuum_permittivity = PhysicalConstant("vacuum_permittivity") + +# vacuum impedance: +Z0 = vacuum_impedance = PhysicalConstant("vacuum_impedance", abbrev='Z_0', latex_repr=r'Z_{0}') + +# Coulomb's constant: +coulomb_constant = coulombs_constant = electric_force_constant = \ + PhysicalConstant("coulomb_constant", abbrev="k_e") + + +atmosphere = atmospheres = atm = Quantity("atmosphere", abbrev="atm") + +kPa = kilopascal = Quantity("kilopascal", abbrev="kPa") +kilopascal.set_global_relative_scale_factor(kilo, Pa) + +bar = bars = Quantity("bar", abbrev="bar") + +pound = pounds = Quantity("pound") # exact + +psi = Quantity("psi") + +dHg0 = 13.5951 # approx value at 0 C +mmHg = torr = Quantity("mmHg") + +atmosphere.set_global_relative_scale_factor(101325, pascal) +bar.set_global_relative_scale_factor(100, kPa) +pound.set_global_relative_scale_factor(Rational(45359237, 100000000), kg) + +mmu = mmus = milli_mass_unit = Quantity("milli_mass_unit") + +quart = quarts = Quantity("quart") + + +# Other convenient units and magnitudes + +ly = lightyear = lightyears = Quantity("lightyear", abbrev="ly") + +au = astronomical_unit = astronomical_units = Quantity("astronomical_unit", abbrev="AU") + + +# Fundamental Planck units: +planck_mass = Quantity("planck_mass", abbrev="m_P", latex_repr=r'm_\text{P}') + +planck_time = Quantity("planck_time", abbrev="t_P", latex_repr=r't_\text{P}') + +planck_temperature = Quantity("planck_temperature", abbrev="T_P", + latex_repr=r'T_\text{P}') + +planck_length = Quantity("planck_length", abbrev="l_P", latex_repr=r'l_\text{P}') + +planck_charge = Quantity("planck_charge", abbrev="q_P", latex_repr=r'q_\text{P}') + + +# Derived Planck units: +planck_area = Quantity("planck_area") + +planck_volume = Quantity("planck_volume") + +planck_momentum = Quantity("planck_momentum") + +planck_energy = Quantity("planck_energy", abbrev="E_P", latex_repr=r'E_\text{P}') + +planck_force = Quantity("planck_force", abbrev="F_P", latex_repr=r'F_\text{P}') + +planck_power = Quantity("planck_power", abbrev="P_P", latex_repr=r'P_\text{P}') + +planck_density = Quantity("planck_density", abbrev="rho_P", latex_repr=r'\rho_\text{P}') + +planck_energy_density = Quantity("planck_energy_density", abbrev="rho^E_P") + +planck_intensity = Quantity("planck_intensity", abbrev="I_P", latex_repr=r'I_\text{P}') + +planck_angular_frequency = Quantity("planck_angular_frequency", abbrev="omega_P", + latex_repr=r'\omega_\text{P}') + +planck_pressure = Quantity("planck_pressure", abbrev="p_P", latex_repr=r'p_\text{P}') + +planck_current = Quantity("planck_current", abbrev="I_P", latex_repr=r'I_\text{P}') + +planck_voltage = Quantity("planck_voltage", abbrev="V_P", latex_repr=r'V_\text{P}') + +planck_impedance = Quantity("planck_impedance", abbrev="Z_P", latex_repr=r'Z_\text{P}') + +planck_acceleration = Quantity("planck_acceleration", abbrev="a_P", + latex_repr=r'a_\text{P}') + + +# Information theory units: +bit = bits = Quantity("bit") +bit.set_global_dimension(information) + +byte = bytes = Quantity("byte") + +kibibyte = kibibytes = Quantity("kibibyte") +mebibyte = mebibytes = Quantity("mebibyte") +gibibyte = gibibytes = Quantity("gibibyte") +tebibyte = tebibytes = Quantity("tebibyte") +pebibyte = pebibytes = Quantity("pebibyte") +exbibyte = exbibytes = Quantity("exbibyte") + +byte.set_global_relative_scale_factor(8, bit) +kibibyte.set_global_relative_scale_factor(kibi, byte) +mebibyte.set_global_relative_scale_factor(mebi, byte) +gibibyte.set_global_relative_scale_factor(gibi, byte) +tebibyte.set_global_relative_scale_factor(tebi, byte) +pebibyte.set_global_relative_scale_factor(pebi, byte) +exbibyte.set_global_relative_scale_factor(exbi, byte) + +# Older units for radioactivity +curie = Ci = Quantity("curie", abbrev="Ci") + +rutherford = Rd = Quantity("rutherford", abbrev="Rd") diff --git a/lib/python3.12/site-packages/sympy/physics/units/dimensions.py b/lib/python3.12/site-packages/sympy/physics/units/dimensions.py new file mode 100644 index 0000000000000000000000000000000000000000..951f8ab17a58606e74f1c14ffa312fedbeebb4b6 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/dimensions.py @@ -0,0 +1,590 @@ +""" +Definition of physical dimensions. + +Unit systems will be constructed on top of these dimensions. + +Most of the examples in the doc use MKS system and are presented from the +computer point of view: from a human point, adding length to time is not legal +in MKS but it is in natural system; for a computer in natural system there is +no time dimension (but a velocity dimension instead) - in the basis - so the +question of adding time to length has no meaning. +""" + +from __future__ import annotations + +import collections +from functools import reduce + +from sympy.core.basic import Basic +from sympy.core.containers import (Dict, Tuple) +from sympy.core.singleton import S +from sympy.core.sorting import default_sort_key +from sympy.core.symbol import Symbol +from sympy.core.sympify import sympify +from sympy.matrices.dense import Matrix +from sympy.functions.elementary.trigonometric import TrigonometricFunction +from sympy.core.expr import Expr +from sympy.core.power import Pow + + +class _QuantityMapper: + + _quantity_scale_factors_global: dict[Expr, Expr] = {} + _quantity_dimensional_equivalence_map_global: dict[Expr, Expr] = {} + _quantity_dimension_global: dict[Expr, Expr] = {} + + def __init__(self, *args, **kwargs): + self._quantity_dimension_map = {} + self._quantity_scale_factors = {} + + def set_quantity_dimension(self, quantity, dimension): + """ + Set the dimension for the quantity in a unit system. + + If this relation is valid in every unit system, use + ``quantity.set_global_dimension(dimension)`` instead. + """ + from sympy.physics.units import Quantity + dimension = sympify(dimension) + if not isinstance(dimension, Dimension): + if dimension == 1: + dimension = Dimension(1) + else: + raise ValueError("expected dimension or 1") + elif isinstance(dimension, Quantity): + dimension = self.get_quantity_dimension(dimension) + self._quantity_dimension_map[quantity] = dimension + + def set_quantity_scale_factor(self, quantity, scale_factor): + """ + Set the scale factor of a quantity relative to another quantity. + + It should be used only once per quantity to just one other quantity, + the algorithm will then be able to compute the scale factors to all + other quantities. + + In case the scale factor is valid in every unit system, please use + ``quantity.set_global_relative_scale_factor(scale_factor)`` instead. + """ + from sympy.physics.units import Quantity + from sympy.physics.units.prefixes import Prefix + scale_factor = sympify(scale_factor) + # replace all prefixes by their ratio to canonical units: + scale_factor = scale_factor.replace( + lambda x: isinstance(x, Prefix), + lambda x: x.scale_factor + ) + # replace all quantities by their ratio to canonical units: + scale_factor = scale_factor.replace( + lambda x: isinstance(x, Quantity), + lambda x: self.get_quantity_scale_factor(x) + ) + self._quantity_scale_factors[quantity] = scale_factor + + def get_quantity_dimension(self, unit): + from sympy.physics.units import Quantity + # First look-up the local dimension map, then the global one: + if unit in self._quantity_dimension_map: + return self._quantity_dimension_map[unit] + if unit in self._quantity_dimension_global: + return self._quantity_dimension_global[unit] + if unit in self._quantity_dimensional_equivalence_map_global: + dep_unit = self._quantity_dimensional_equivalence_map_global[unit] + if isinstance(dep_unit, Quantity): + return self.get_quantity_dimension(dep_unit) + else: + return Dimension(self.get_dimensional_expr(dep_unit)) + if isinstance(unit, Quantity): + return Dimension(unit.name) + else: + return Dimension(1) + + def get_quantity_scale_factor(self, unit): + if unit in self._quantity_scale_factors: + return self._quantity_scale_factors[unit] + if unit in self._quantity_scale_factors_global: + mul_factor, other_unit = self._quantity_scale_factors_global[unit] + return mul_factor*self.get_quantity_scale_factor(other_unit) + return S.One + + +class Dimension(Expr): + """ + This class represent the dimension of a physical quantities. + + The ``Dimension`` constructor takes as parameters a name and an optional + symbol. + + For example, in classical mechanics we know that time is different from + temperature and dimensions make this difference (but they do not provide + any measure of these quantites. + + >>> from sympy.physics.units import Dimension + >>> length = Dimension('length') + >>> length + Dimension(length) + >>> time = Dimension('time') + >>> time + Dimension(time) + + Dimensions can be composed using multiplication, division and + exponentiation (by a number) to give new dimensions. Addition and + subtraction is defined only when the two objects are the same dimension. + + >>> velocity = length / time + >>> velocity + Dimension(length/time) + + It is possible to use a dimension system object to get the dimensionsal + dependencies of a dimension, for example the dimension system used by the + SI units convention can be used: + + >>> from sympy.physics.units.systems.si import dimsys_SI + >>> dimsys_SI.get_dimensional_dependencies(velocity) + {Dimension(length, L): 1, Dimension(time, T): -1} + >>> length + length + Dimension(length) + >>> l2 = length**2 + >>> l2 + Dimension(length**2) + >>> dimsys_SI.get_dimensional_dependencies(l2) + {Dimension(length, L): 2} + + """ + + _op_priority = 13.0 + + # XXX: This doesn't seem to be used anywhere... + _dimensional_dependencies = {} # type: ignore + + is_commutative = True + is_number = False + # make sqrt(M**2) --> M + is_positive = True + is_real = True + + def __new__(cls, name, symbol=None): + + if isinstance(name, str): + name = Symbol(name) + else: + name = sympify(name) + + if not isinstance(name, Expr): + raise TypeError("Dimension name needs to be a valid math expression") + + if isinstance(symbol, str): + symbol = Symbol(symbol) + elif symbol is not None: + assert isinstance(symbol, Symbol) + + obj = Expr.__new__(cls, name) + + obj._name = name + obj._symbol = symbol + return obj + + @property + def name(self): + return self._name + + @property + def symbol(self): + return self._symbol + + def __str__(self): + """ + Display the string representation of the dimension. + """ + if self.symbol is None: + return "Dimension(%s)" % (self.name) + else: + return "Dimension(%s, %s)" % (self.name, self.symbol) + + def __repr__(self): + return self.__str__() + + def __neg__(self): + return self + + def __add__(self, other): + from sympy.physics.units.quantities import Quantity + other = sympify(other) + if isinstance(other, Basic): + if other.has(Quantity): + raise TypeError("cannot sum dimension and quantity") + if isinstance(other, Dimension) and self == other: + return self + return super().__add__(other) + return self + + def __radd__(self, other): + return self.__add__(other) + + def __sub__(self, other): + # there is no notion of ordering (or magnitude) among dimension, + # subtraction is equivalent to addition when the operation is legal + return self + other + + def __rsub__(self, other): + # there is no notion of ordering (or magnitude) among dimension, + # subtraction is equivalent to addition when the operation is legal + return self + other + + def __pow__(self, other): + return self._eval_power(other) + + def _eval_power(self, other): + other = sympify(other) + return Dimension(self.name**other) + + def __mul__(self, other): + from sympy.physics.units.quantities import Quantity + if isinstance(other, Basic): + if other.has(Quantity): + raise TypeError("cannot sum dimension and quantity") + if isinstance(other, Dimension): + return Dimension(self.name*other.name) + if not other.free_symbols: # other.is_number cannot be used + return self + return super().__mul__(other) + return self + + def __rmul__(self, other): + return self.__mul__(other) + + def __truediv__(self, other): + return self*Pow(other, -1) + + def __rtruediv__(self, other): + return other * pow(self, -1) + + @classmethod + def _from_dimensional_dependencies(cls, dependencies): + return reduce(lambda x, y: x * y, ( + d**e for d, e in dependencies.items() + ), 1) + + def has_integer_powers(self, dim_sys): + """ + Check if the dimension object has only integer powers. + + All the dimension powers should be integers, but rational powers may + appear in intermediate steps. This method may be used to check that the + final result is well-defined. + """ + + return all(dpow.is_Integer for dpow in dim_sys.get_dimensional_dependencies(self).values()) + + +# Create dimensions according to the base units in MKSA. +# For other unit systems, they can be derived by transforming the base +# dimensional dependency dictionary. + + +class DimensionSystem(Basic, _QuantityMapper): + r""" + DimensionSystem represents a coherent set of dimensions. + + The constructor takes three parameters: + + - base dimensions; + - derived dimensions: these are defined in terms of the base dimensions + (for example velocity is defined from the division of length by time); + - dependency of dimensions: how the derived dimensions depend + on the base dimensions. + + Optionally either the ``derived_dims`` or the ``dimensional_dependencies`` + may be omitted. + """ + + def __new__(cls, base_dims, derived_dims=(), dimensional_dependencies={}): + dimensional_dependencies = dict(dimensional_dependencies) + + def parse_dim(dim): + if isinstance(dim, str): + dim = Dimension(Symbol(dim)) + elif isinstance(dim, Dimension): + pass + elif isinstance(dim, Symbol): + dim = Dimension(dim) + else: + raise TypeError("%s wrong type" % dim) + return dim + + base_dims = [parse_dim(i) for i in base_dims] + derived_dims = [parse_dim(i) for i in derived_dims] + + for dim in base_dims: + if (dim in dimensional_dependencies + and (len(dimensional_dependencies[dim]) != 1 or + dimensional_dependencies[dim].get(dim, None) != 1)): + raise IndexError("Repeated value in base dimensions") + dimensional_dependencies[dim] = Dict({dim: 1}) + + def parse_dim_name(dim): + if isinstance(dim, Dimension): + return dim + elif isinstance(dim, str): + return Dimension(Symbol(dim)) + elif isinstance(dim, Symbol): + return Dimension(dim) + else: + raise TypeError("unrecognized type %s for %s" % (type(dim), dim)) + + for dim in dimensional_dependencies.keys(): + dim = parse_dim(dim) + if (dim not in derived_dims) and (dim not in base_dims): + derived_dims.append(dim) + + def parse_dict(d): + return Dict({parse_dim_name(i): j for i, j in d.items()}) + + # Make sure everything is a SymPy type: + dimensional_dependencies = {parse_dim_name(i): parse_dict(j) for i, j in + dimensional_dependencies.items()} + + for dim in derived_dims: + if dim in base_dims: + raise ValueError("Dimension %s both in base and derived" % dim) + if dim not in dimensional_dependencies: + # TODO: should this raise a warning? + dimensional_dependencies[dim] = Dict({dim: 1}) + + base_dims.sort(key=default_sort_key) + derived_dims.sort(key=default_sort_key) + + base_dims = Tuple(*base_dims) + derived_dims = Tuple(*derived_dims) + dimensional_dependencies = Dict({i: Dict(j) for i, j in dimensional_dependencies.items()}) + obj = Basic.__new__(cls, base_dims, derived_dims, dimensional_dependencies) + return obj + + @property + def base_dims(self): + return self.args[0] + + @property + def derived_dims(self): + return self.args[1] + + @property + def dimensional_dependencies(self): + return self.args[2] + + def _get_dimensional_dependencies_for_name(self, dimension): + if isinstance(dimension, str): + dimension = Dimension(Symbol(dimension)) + elif not isinstance(dimension, Dimension): + dimension = Dimension(dimension) + + if dimension.name.is_Symbol: + # Dimensions not included in the dependencies are considered + # as base dimensions: + return dict(self.dimensional_dependencies.get(dimension, {dimension: 1})) + + if dimension.name.is_number or dimension.name.is_NumberSymbol: + return {} + + get_for_name = self._get_dimensional_dependencies_for_name + + if dimension.name.is_Mul: + ret = collections.defaultdict(int) + dicts = [get_for_name(i) for i in dimension.name.args] + for d in dicts: + for k, v in d.items(): + ret[k] += v + return {k: v for (k, v) in ret.items() if v != 0} + + if dimension.name.is_Add: + dicts = [get_for_name(i) for i in dimension.name.args] + if all(d == dicts[0] for d in dicts[1:]): + return dicts[0] + raise TypeError("Only equivalent dimensions can be added or subtracted.") + + if dimension.name.is_Pow: + dim_base = get_for_name(dimension.name.base) + dim_exp = get_for_name(dimension.name.exp) + if dim_exp == {} or dimension.name.exp.is_Symbol: + return {k: v * dimension.name.exp for (k, v) in dim_base.items()} + else: + raise TypeError("The exponent for the power operator must be a Symbol or dimensionless.") + + if dimension.name.is_Function: + args = (Dimension._from_dimensional_dependencies( + get_for_name(arg)) for arg in dimension.name.args) + result = dimension.name.func(*args) + + dicts = [get_for_name(i) for i in dimension.name.args] + + if isinstance(result, Dimension): + return self.get_dimensional_dependencies(result) + elif result.func == dimension.name.func: + if isinstance(dimension.name, TrigonometricFunction): + if dicts[0] in ({}, {Dimension('angle'): 1}): + return {} + else: + raise TypeError("The input argument for the function {} must be dimensionless or have dimensions of angle.".format(dimension.func)) + else: + if all(item == {} for item in dicts): + return {} + else: + raise TypeError("The input arguments for the function {} must be dimensionless.".format(dimension.func)) + else: + return get_for_name(result) + + raise TypeError("Type {} not implemented for get_dimensional_dependencies".format(type(dimension.name))) + + def get_dimensional_dependencies(self, name, mark_dimensionless=False): + dimdep = self._get_dimensional_dependencies_for_name(name) + if mark_dimensionless and dimdep == {}: + return {Dimension(1): 1} + return dict(dimdep.items()) + + def equivalent_dims(self, dim1, dim2): + deps1 = self.get_dimensional_dependencies(dim1) + deps2 = self.get_dimensional_dependencies(dim2) + return deps1 == deps2 + + def extend(self, new_base_dims, new_derived_dims=(), new_dim_deps=None): + deps = dict(self.dimensional_dependencies) + if new_dim_deps: + deps.update(new_dim_deps) + + new_dim_sys = DimensionSystem( + tuple(self.base_dims) + tuple(new_base_dims), + tuple(self.derived_dims) + tuple(new_derived_dims), + deps + ) + new_dim_sys._quantity_dimension_map.update(self._quantity_dimension_map) + new_dim_sys._quantity_scale_factors.update(self._quantity_scale_factors) + return new_dim_sys + + def is_dimensionless(self, dimension): + """ + Check if the dimension object really has a dimension. + + A dimension should have at least one component with non-zero power. + """ + if dimension.name == 1: + return True + return self.get_dimensional_dependencies(dimension) == {} + + @property + def list_can_dims(self): + """ + Useless method, kept for compatibility with previous versions. + + DO NOT USE. + + List all canonical dimension names. + """ + dimset = set() + for i in self.base_dims: + dimset.update(set(self.get_dimensional_dependencies(i).keys())) + return tuple(sorted(dimset, key=str)) + + @property + def inv_can_transf_matrix(self): + """ + Useless method, kept for compatibility with previous versions. + + DO NOT USE. + + Compute the inverse transformation matrix from the base to the + canonical dimension basis. + + It corresponds to the matrix where columns are the vector of base + dimensions in canonical basis. + + This matrix will almost never be used because dimensions are always + defined with respect to the canonical basis, so no work has to be done + to get them in this basis. Nonetheless if this matrix is not square + (or not invertible) it means that we have chosen a bad basis. + """ + matrix = reduce(lambda x, y: x.row_join(y), + [self.dim_can_vector(d) for d in self.base_dims]) + return matrix + + @property + def can_transf_matrix(self): + """ + Useless method, kept for compatibility with previous versions. + + DO NOT USE. + + Return the canonical transformation matrix from the canonical to the + base dimension basis. + + It is the inverse of the matrix computed with inv_can_transf_matrix(). + """ + + #TODO: the inversion will fail if the system is inconsistent, for + # example if the matrix is not a square + return reduce(lambda x, y: x.row_join(y), + [self.dim_can_vector(d) for d in sorted(self.base_dims, key=str)] + ).inv() + + def dim_can_vector(self, dim): + """ + Useless method, kept for compatibility with previous versions. + + DO NOT USE. + + Dimensional representation in terms of the canonical base dimensions. + """ + + vec = [] + for d in self.list_can_dims: + vec.append(self.get_dimensional_dependencies(dim).get(d, 0)) + return Matrix(vec) + + def dim_vector(self, dim): + """ + Useless method, kept for compatibility with previous versions. + + DO NOT USE. + + + Vector representation in terms of the base dimensions. + """ + return self.can_transf_matrix * Matrix(self.dim_can_vector(dim)) + + def print_dim_base(self, dim): + """ + Give the string expression of a dimension in term of the basis symbols. + """ + dims = self.dim_vector(dim) + symbols = [i.symbol if i.symbol is not None else i.name for i in self.base_dims] + res = S.One + for (s, p) in zip(symbols, dims): + res *= s**p + return res + + @property + def dim(self): + """ + Useless method, kept for compatibility with previous versions. + + DO NOT USE. + + Give the dimension of the system. + + That is return the number of dimensions forming the basis. + """ + return len(self.base_dims) + + @property + def is_consistent(self): + """ + Useless method, kept for compatibility with previous versions. + + DO NOT USE. + + Check if the system is well defined. + """ + + # not enough or too many base dimensions compared to independent + # dimensions + # in vector language: the set of vectors do not form a basis + return self.inv_can_transf_matrix.is_square diff --git a/lib/python3.12/site-packages/sympy/physics/units/prefixes.py b/lib/python3.12/site-packages/sympy/physics/units/prefixes.py new file mode 100644 index 0000000000000000000000000000000000000000..44fd7cb9efe4b1d6307810af6b9cd140817126f9 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/prefixes.py @@ -0,0 +1,219 @@ +""" +Module defining unit prefixe class and some constants. + +Constant dict for SI and binary prefixes are defined as PREFIXES and +BIN_PREFIXES. +""" +from sympy.core.expr import Expr +from sympy.core.sympify import sympify +from sympy.core.singleton import S + +class Prefix(Expr): + """ + This class represent prefixes, with their name, symbol and factor. + + Prefixes are used to create derived units from a given unit. They should + always be encapsulated into units. + + The factor is constructed from a base (default is 10) to some power, and + it gives the total multiple or fraction. For example the kilometer km + is constructed from the meter (factor 1) and the kilo (10 to the power 3, + i.e. 1000). The base can be changed to allow e.g. binary prefixes. + + A prefix multiplied by something will always return the product of this + other object times the factor, except if the other object: + + - is a prefix and they can be combined into a new prefix; + - defines multiplication with prefixes (which is the case for the Unit + class). + """ + _op_priority = 13.0 + is_commutative = True + + def __new__(cls, name, abbrev, exponent, base=sympify(10), latex_repr=None): + + name = sympify(name) + abbrev = sympify(abbrev) + exponent = sympify(exponent) + base = sympify(base) + + obj = Expr.__new__(cls, name, abbrev, exponent, base) + obj._name = name + obj._abbrev = abbrev + obj._scale_factor = base**exponent + obj._exponent = exponent + obj._base = base + obj._latex_repr = latex_repr + return obj + + @property + def name(self): + return self._name + + @property + def abbrev(self): + return self._abbrev + + @property + def scale_factor(self): + return self._scale_factor + + def _latex(self, printer): + if self._latex_repr is None: + return r'\text{%s}' % self._abbrev + return self._latex_repr + + @property + def base(self): + return self._base + + def __str__(self): + return str(self._abbrev) + + def __repr__(self): + if self.base == 10: + return "Prefix(%r, %r, %r)" % ( + str(self.name), str(self.abbrev), self._exponent) + else: + return "Prefix(%r, %r, %r, %r)" % ( + str(self.name), str(self.abbrev), self._exponent, self.base) + + def __mul__(self, other): + from sympy.physics.units import Quantity + if not isinstance(other, (Quantity, Prefix)): + return super().__mul__(other) + + fact = self.scale_factor * other.scale_factor + + if isinstance(other, Prefix): + if fact == 1: + return S.One + # simplify prefix + for p in PREFIXES: + if PREFIXES[p].scale_factor == fact: + return PREFIXES[p] + return fact + + return self.scale_factor * other + + def __truediv__(self, other): + if not hasattr(other, "scale_factor"): + return super().__truediv__(other) + + fact = self.scale_factor / other.scale_factor + + if fact == 1: + return S.One + elif isinstance(other, Prefix): + for p in PREFIXES: + if PREFIXES[p].scale_factor == fact: + return PREFIXES[p] + return fact + + return self.scale_factor / other + + def __rtruediv__(self, other): + if other == 1: + for p in PREFIXES: + if PREFIXES[p].scale_factor == 1 / self.scale_factor: + return PREFIXES[p] + return other / self.scale_factor + + +def prefix_unit(unit, prefixes): + """ + Return a list of all units formed by unit and the given prefixes. + + You can use the predefined PREFIXES or BIN_PREFIXES, but you can also + pass as argument a subdict of them if you do not want all prefixed units. + + >>> from sympy.physics.units.prefixes import (PREFIXES, + ... prefix_unit) + >>> from sympy.physics.units import m + >>> pref = {"m": PREFIXES["m"], "c": PREFIXES["c"], "d": PREFIXES["d"]} + >>> prefix_unit(m, pref) # doctest: +SKIP + [millimeter, centimeter, decimeter] + """ + + from sympy.physics.units.quantities import Quantity + from sympy.physics.units import UnitSystem + + prefixed_units = [] + + for prefix in prefixes.values(): + quantity = Quantity( + "%s%s" % (prefix.name, unit.name), + abbrev=("%s%s" % (prefix.abbrev, unit.abbrev)), + is_prefixed=True, + ) + UnitSystem._quantity_dimensional_equivalence_map_global[quantity] = unit + UnitSystem._quantity_scale_factors_global[quantity] = (prefix.scale_factor, unit) + prefixed_units.append(quantity) + + return prefixed_units + + +yotta = Prefix('yotta', 'Y', 24) +zetta = Prefix('zetta', 'Z', 21) +exa = Prefix('exa', 'E', 18) +peta = Prefix('peta', 'P', 15) +tera = Prefix('tera', 'T', 12) +giga = Prefix('giga', 'G', 9) +mega = Prefix('mega', 'M', 6) +kilo = Prefix('kilo', 'k', 3) +hecto = Prefix('hecto', 'h', 2) +deca = Prefix('deca', 'da', 1) +deci = Prefix('deci', 'd', -1) +centi = Prefix('centi', 'c', -2) +milli = Prefix('milli', 'm', -3) +micro = Prefix('micro', 'mu', -6, latex_repr=r"\mu") +nano = Prefix('nano', 'n', -9) +pico = Prefix('pico', 'p', -12) +femto = Prefix('femto', 'f', -15) +atto = Prefix('atto', 'a', -18) +zepto = Prefix('zepto', 'z', -21) +yocto = Prefix('yocto', 'y', -24) + + +# https://physics.nist.gov/cuu/Units/prefixes.html +PREFIXES = { + 'Y': yotta, + 'Z': zetta, + 'E': exa, + 'P': peta, + 'T': tera, + 'G': giga, + 'M': mega, + 'k': kilo, + 'h': hecto, + 'da': deca, + 'd': deci, + 'c': centi, + 'm': milli, + 'mu': micro, + 'n': nano, + 'p': pico, + 'f': femto, + 'a': atto, + 'z': zepto, + 'y': yocto, +} + + +kibi = Prefix('kibi', 'Y', 10, 2) +mebi = Prefix('mebi', 'Y', 20, 2) +gibi = Prefix('gibi', 'Y', 30, 2) +tebi = Prefix('tebi', 'Y', 40, 2) +pebi = Prefix('pebi', 'Y', 50, 2) +exbi = Prefix('exbi', 'Y', 60, 2) + + +# https://physics.nist.gov/cuu/Units/binary.html +BIN_PREFIXES = { + 'Ki': kibi, + 'Mi': mebi, + 'Gi': gibi, + 'Ti': tebi, + 'Pi': pebi, + 'Ei': exbi, +} diff --git a/lib/python3.12/site-packages/sympy/physics/units/quantities.py b/lib/python3.12/site-packages/sympy/physics/units/quantities.py new file mode 100644 index 0000000000000000000000000000000000000000..cc19e72aea83b5bd8ae7cf2f63dd49388a3815ee --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/quantities.py @@ -0,0 +1,152 @@ +""" +Physical quantities. +""" + +from sympy.core.expr import AtomicExpr +from sympy.core.symbol import Symbol +from sympy.core.sympify import sympify +from sympy.physics.units.dimensions import _QuantityMapper +from sympy.physics.units.prefixes import Prefix + + +class Quantity(AtomicExpr): + """ + Physical quantity: can be a unit of measure, a constant or a generic quantity. + """ + + is_commutative = True + is_real = True + is_number = False + is_nonzero = True + is_physical_constant = False + _diff_wrt = True + + def __new__(cls, name, abbrev=None, + latex_repr=None, pretty_unicode_repr=None, + pretty_ascii_repr=None, mathml_presentation_repr=None, + is_prefixed=False, + **assumptions): + + if not isinstance(name, Symbol): + name = Symbol(name) + + if abbrev is None: + abbrev = name + elif isinstance(abbrev, str): + abbrev = Symbol(abbrev) + + # HACK: These are here purely for type checking. They actually get assigned below. + cls._is_prefixed = is_prefixed + + obj = AtomicExpr.__new__(cls, name, abbrev) + obj._name = name + obj._abbrev = abbrev + obj._latex_repr = latex_repr + obj._unicode_repr = pretty_unicode_repr + obj._ascii_repr = pretty_ascii_repr + obj._mathml_repr = mathml_presentation_repr + obj._is_prefixed = is_prefixed + return obj + + def set_global_dimension(self, dimension): + _QuantityMapper._quantity_dimension_global[self] = dimension + + def set_global_relative_scale_factor(self, scale_factor, reference_quantity): + """ + Setting a scale factor that is valid across all unit system. + """ + from sympy.physics.units import UnitSystem + scale_factor = sympify(scale_factor) + if isinstance(scale_factor, Prefix): + self._is_prefixed = True + # replace all prefixes by their ratio to canonical units: + scale_factor = scale_factor.replace( + lambda x: isinstance(x, Prefix), + lambda x: x.scale_factor + ) + scale_factor = sympify(scale_factor) + UnitSystem._quantity_scale_factors_global[self] = (scale_factor, reference_quantity) + UnitSystem._quantity_dimensional_equivalence_map_global[self] = reference_quantity + + @property + def name(self): + return self._name + + @property + def dimension(self): + from sympy.physics.units import UnitSystem + unit_system = UnitSystem.get_default_unit_system() + return unit_system.get_quantity_dimension(self) + + @property + def abbrev(self): + """ + Symbol representing the unit name. + + Prepend the abbreviation with the prefix symbol if it is defines. + """ + return self._abbrev + + @property + def scale_factor(self): + """ + Overall magnitude of the quantity as compared to the canonical units. + """ + from sympy.physics.units import UnitSystem + unit_system = UnitSystem.get_default_unit_system() + return unit_system.get_quantity_scale_factor(self) + + def _eval_is_positive(self): + return True + + def _eval_is_constant(self): + return True + + def _eval_Abs(self): + return self + + def _eval_subs(self, old, new): + if isinstance(new, Quantity) and self != old: + return self + + def _latex(self, printer): + if self._latex_repr: + return self._latex_repr + else: + return r'\text{{{}}}'.format(self.args[1] \ + if len(self.args) >= 2 else self.args[0]) + + def convert_to(self, other, unit_system="SI"): + """ + Convert the quantity to another quantity of same dimensions. + + Examples + ======== + + >>> from sympy.physics.units import speed_of_light, meter, second + >>> speed_of_light + speed_of_light + >>> speed_of_light.convert_to(meter/second) + 299792458*meter/second + + >>> from sympy.physics.units import liter + >>> liter.convert_to(meter**3) + meter**3/1000 + """ + from .util import convert_to + return convert_to(self, other, unit_system) + + @property + def free_symbols(self): + """Return free symbols from quantity.""" + return set() + + @property + def is_prefixed(self): + """Whether or not the quantity is prefixed. Eg. `kilogram` is prefixed, but `gram` is not.""" + return self._is_prefixed + +class PhysicalConstant(Quantity): + """Represents a physical constant, eg. `speed_of_light` or `avogadro_constant`.""" + + is_physical_constant = True diff --git a/lib/python3.12/site-packages/sympy/physics/units/systems/__init__.py b/lib/python3.12/site-packages/sympy/physics/units/systems/__init__.py new file mode 100644 index 0000000000000000000000000000000000000000..7c4f28d42eec86be8d679227f7b11ed7d48e61f1 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/systems/__init__.py @@ -0,0 +1,6 @@ +from sympy.physics.units.systems.mks import MKS +from sympy.physics.units.systems.mksa import MKSA +from sympy.physics.units.systems.natural import natural +from sympy.physics.units.systems.si import SI + +__all__ = ['MKS', 'MKSA', 'natural', 'SI'] diff --git a/lib/python3.12/site-packages/sympy/physics/units/systems/__pycache__/__init__.cpython-312.pyc 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a/lib/python3.12/site-packages/sympy/physics/units/systems/cgs.py b/lib/python3.12/site-packages/sympy/physics/units/systems/cgs.py new file mode 100644 index 0000000000000000000000000000000000000000..1f5ee0b5454f1998672e1979ae4eaabe57a8edb4 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/systems/cgs.py @@ -0,0 +1,82 @@ +from sympy.core.singleton import S +from sympy.functions.elementary.miscellaneous import sqrt +from sympy.physics.units import UnitSystem, centimeter, gram, second, coulomb, charge, speed_of_light, current, mass, \ + length, voltage, magnetic_density, magnetic_flux +from sympy.physics.units.definitions import coulombs_constant +from sympy.physics.units.definitions.unit_definitions import statcoulomb, statampere, statvolt, volt, tesla, gauss, \ + weber, maxwell, debye, oersted, ohm, farad, henry, erg, ampere, coulomb_constant +from sympy.physics.units.systems.mks import dimsys_length_weight_time + +One = S.One + +dimsys_cgs = dimsys_length_weight_time.extend( + [], + new_dim_deps={ + # Dimensional dependencies for derived dimensions + "impedance": {"time": 1, "length": -1}, + "conductance": {"time": -1, "length": 1}, + "capacitance": {"length": 1}, + "inductance": {"time": 2, "length": -1}, + "charge": {"mass": S.Half, "length": S(3)/2, "time": -1}, + "current": {"mass": One/2, "length": 3*One/2, "time": -2}, + "voltage": {"length": -One/2, "mass": One/2, "time": -1}, + "magnetic_density": {"length": -One/2, "mass": One/2, "time": -1}, + "magnetic_flux": {"length": 3*One/2, "mass": One/2, "time": -1}, + } +) + +cgs_gauss = UnitSystem( + base_units=[centimeter, gram, second], + units=[], + name="cgs_gauss", + dimension_system=dimsys_cgs) + + +cgs_gauss.set_quantity_scale_factor(coulombs_constant, 1) + +cgs_gauss.set_quantity_dimension(statcoulomb, charge) +cgs_gauss.set_quantity_scale_factor(statcoulomb, centimeter**(S(3)/2)*gram**(S.Half)/second) + +cgs_gauss.set_quantity_dimension(coulomb, charge) + +cgs_gauss.set_quantity_dimension(statampere, current) +cgs_gauss.set_quantity_scale_factor(statampere, statcoulomb/second) + +cgs_gauss.set_quantity_dimension(statvolt, voltage) +cgs_gauss.set_quantity_scale_factor(statvolt, erg/statcoulomb) + +cgs_gauss.set_quantity_dimension(volt, voltage) + +cgs_gauss.set_quantity_dimension(gauss, magnetic_density) +cgs_gauss.set_quantity_scale_factor(gauss, sqrt(gram/centimeter)/second) + +cgs_gauss.set_quantity_dimension(tesla, magnetic_density) + +cgs_gauss.set_quantity_dimension(maxwell, magnetic_flux) +cgs_gauss.set_quantity_scale_factor(maxwell, sqrt(centimeter**3*gram)/second) + +# SI units expressed in CGS-gaussian units: +cgs_gauss.set_quantity_scale_factor(coulomb, 10*speed_of_light*statcoulomb) +cgs_gauss.set_quantity_scale_factor(ampere, 10*speed_of_light*statcoulomb/second) +cgs_gauss.set_quantity_scale_factor(volt, 10**6/speed_of_light*statvolt) +cgs_gauss.set_quantity_scale_factor(weber, 10**8*maxwell) +cgs_gauss.set_quantity_scale_factor(tesla, 10**4*gauss) +cgs_gauss.set_quantity_scale_factor(debye, One/10**18*statcoulomb*centimeter) +cgs_gauss.set_quantity_scale_factor(oersted, sqrt(gram/centimeter)/second) +cgs_gauss.set_quantity_scale_factor(ohm, 10**5/speed_of_light**2*second/centimeter) +cgs_gauss.set_quantity_scale_factor(farad, One/10**5*speed_of_light**2*centimeter) +cgs_gauss.set_quantity_scale_factor(henry, 10**5/speed_of_light**2/centimeter*second**2) + +# Coulomb's constant: +cgs_gauss.set_quantity_dimension(coulomb_constant, 1) +cgs_gauss.set_quantity_scale_factor(coulomb_constant, 1) + +__all__ = [ + 'ohm', 'tesla', 'maxwell', 'speed_of_light', 'volt', 'second', 'voltage', + 'debye', 'dimsys_length_weight_time', 'centimeter', 'coulomb_constant', + 'farad', 'sqrt', 'UnitSystem', 'current', 'charge', 'weber', 'gram', + 'statcoulomb', 'gauss', 'S', 'statvolt', 'oersted', 'statampere', + 'dimsys_cgs', 'coulomb', 'magnetic_density', 'magnetic_flux', 'One', + 'length', 'erg', 'mass', 'coulombs_constant', 'henry', 'ampere', + 'cgs_gauss', +] diff --git a/lib/python3.12/site-packages/sympy/physics/units/systems/length_weight_time.py b/lib/python3.12/site-packages/sympy/physics/units/systems/length_weight_time.py new file mode 100644 index 0000000000000000000000000000000000000000..dca4ded82afb8ff0e45f197e51c23850ca824737 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/systems/length_weight_time.py @@ -0,0 +1,156 @@ +from sympy.core.singleton import S + +from sympy.core.numbers import pi + +from sympy.physics.units import DimensionSystem, hertz, kilogram +from sympy.physics.units.definitions import ( + G, Hz, J, N, Pa, W, c, g, kg, m, s, meter, gram, second, newton, + joule, watt, pascal) +from sympy.physics.units.definitions.dimension_definitions import ( + acceleration, action, energy, force, frequency, momentum, + power, pressure, velocity, length, mass, time) +from sympy.physics.units.prefixes import PREFIXES, prefix_unit +from sympy.physics.units.prefixes import ( + kibi, mebi, gibi, tebi, pebi, exbi +) +from sympy.physics.units.definitions import ( + cd, K, coulomb, volt, ohm, siemens, farad, henry, tesla, weber, dioptre, + lux, katal, gray, becquerel, inch, hectare, liter, julian_year, + gravitational_constant, speed_of_light, elementary_charge, planck, hbar, + electronvolt, avogadro_number, avogadro_constant, boltzmann_constant, + stefan_boltzmann_constant, atomic_mass_constant, molar_gas_constant, + faraday_constant, josephson_constant, von_klitzing_constant, + acceleration_due_to_gravity, magnetic_constant, vacuum_permittivity, + vacuum_impedance, coulomb_constant, atmosphere, bar, pound, psi, mmHg, + milli_mass_unit, quart, lightyear, astronomical_unit, planck_mass, + planck_time, planck_temperature, planck_length, planck_charge, + planck_area, planck_volume, planck_momentum, planck_energy, planck_force, + planck_power, planck_density, planck_energy_density, planck_intensity, + planck_angular_frequency, planck_pressure, planck_current, planck_voltage, + planck_impedance, planck_acceleration, bit, byte, kibibyte, mebibyte, + gibibyte, tebibyte, pebibyte, exbibyte, curie, rutherford, radian, degree, + steradian, angular_mil, atomic_mass_unit, gee, kPa, ampere, u0, kelvin, + mol, mole, candela, electric_constant, boltzmann, angstrom +) + + +dimsys_length_weight_time = DimensionSystem([ + # Dimensional dependencies for MKS base dimensions + length, + mass, + time, +], dimensional_dependencies={ + # Dimensional dependencies for derived dimensions + "velocity": {"length": 1, "time": -1}, + "acceleration": {"length": 1, "time": -2}, + "momentum": {"mass": 1, "length": 1, "time": -1}, + "force": {"mass": 1, "length": 1, "time": -2}, + "energy": {"mass": 1, "length": 2, "time": -2}, + "power": {"length": 2, "mass": 1, "time": -3}, + "pressure": {"mass": 1, "length": -1, "time": -2}, + "frequency": {"time": -1}, + "action": {"length": 2, "mass": 1, "time": -1}, + "area": {"length": 2}, + "volume": {"length": 3}, +}) + + +One = S.One + + +# Base units: +dimsys_length_weight_time.set_quantity_dimension(meter, length) +dimsys_length_weight_time.set_quantity_scale_factor(meter, One) + +# gram; used to define its prefixed units +dimsys_length_weight_time.set_quantity_dimension(gram, mass) +dimsys_length_weight_time.set_quantity_scale_factor(gram, One) + +dimsys_length_weight_time.set_quantity_dimension(second, time) +dimsys_length_weight_time.set_quantity_scale_factor(second, One) + +# derived units + +dimsys_length_weight_time.set_quantity_dimension(newton, force) +dimsys_length_weight_time.set_quantity_scale_factor(newton, kilogram*meter/second**2) + +dimsys_length_weight_time.set_quantity_dimension(joule, energy) +dimsys_length_weight_time.set_quantity_scale_factor(joule, newton*meter) + +dimsys_length_weight_time.set_quantity_dimension(watt, power) +dimsys_length_weight_time.set_quantity_scale_factor(watt, joule/second) + +dimsys_length_weight_time.set_quantity_dimension(pascal, pressure) +dimsys_length_weight_time.set_quantity_scale_factor(pascal, newton/meter**2) + +dimsys_length_weight_time.set_quantity_dimension(hertz, frequency) +dimsys_length_weight_time.set_quantity_scale_factor(hertz, One) + +# Other derived units: + +dimsys_length_weight_time.set_quantity_dimension(dioptre, 1 / length) +dimsys_length_weight_time.set_quantity_scale_factor(dioptre, 1/meter) + +# Common volume and area units + +dimsys_length_weight_time.set_quantity_dimension(hectare, length**2) +dimsys_length_weight_time.set_quantity_scale_factor(hectare, (meter**2)*(10000)) + +dimsys_length_weight_time.set_quantity_dimension(liter, length**3) +dimsys_length_weight_time.set_quantity_scale_factor(liter, meter**3/1000) + + +# Newton constant +# REF: NIST SP 959 (June 2019) + +dimsys_length_weight_time.set_quantity_dimension(gravitational_constant, length ** 3 * mass ** -1 * time ** -2) +dimsys_length_weight_time.set_quantity_scale_factor(gravitational_constant, 6.67430e-11*m**3/(kg*s**2)) + +# speed of light + +dimsys_length_weight_time.set_quantity_dimension(speed_of_light, velocity) +dimsys_length_weight_time.set_quantity_scale_factor(speed_of_light, 299792458*meter/second) + + +# Planck constant +# REF: NIST SP 959 (June 2019) + +dimsys_length_weight_time.set_quantity_dimension(planck, action) +dimsys_length_weight_time.set_quantity_scale_factor(planck, 6.62607015e-34*joule*second) + +# Reduced Planck constant +# REF: NIST SP 959 (June 2019) + +dimsys_length_weight_time.set_quantity_dimension(hbar, action) +dimsys_length_weight_time.set_quantity_scale_factor(hbar, planck / (2 * pi)) + + +__all__ = [ + 'mmHg', 'atmosphere', 'newton', 'meter', 'vacuum_permittivity', 'pascal', + 'magnetic_constant', 'angular_mil', 'julian_year', 'weber', 'exbibyte', + 'liter', 'molar_gas_constant', 'faraday_constant', 'avogadro_constant', + 'planck_momentum', 'planck_density', 'gee', 'mol', 'bit', 'gray', 'kibi', + 'bar', 'curie', 'prefix_unit', 'PREFIXES', 'planck_time', 'gram', + 'candela', 'force', 'planck_intensity', 'energy', 'becquerel', + 'planck_acceleration', 'speed_of_light', 'dioptre', 'second', 'frequency', + 'Hz', 'power', 'lux', 'planck_current', 'momentum', 'tebibyte', + 'planck_power', 'degree', 'mebi', 'K', 'planck_volume', + 'quart', 'pressure', 'W', 'joule', 'boltzmann_constant', 'c', 'g', + 'planck_force', 'exbi', 's', 'watt', 'action', 'hbar', 'gibibyte', + 'DimensionSystem', 'cd', 'volt', 'planck_charge', 'angstrom', + 'dimsys_length_weight_time', 'pebi', 'vacuum_impedance', 'planck', + 'farad', 'gravitational_constant', 'u0', 'hertz', 'tesla', 'steradian', + 'josephson_constant', 'planck_area', 'stefan_boltzmann_constant', + 'astronomical_unit', 'J', 'N', 'planck_voltage', 'planck_energy', + 'atomic_mass_constant', 'rutherford', 'elementary_charge', 'Pa', + 'planck_mass', 'henry', 'planck_angular_frequency', 'ohm', 'pound', + 'planck_pressure', 'G', 'avogadro_number', 'psi', 'von_klitzing_constant', + 'planck_length', 'radian', 'mole', 'acceleration', + 'planck_energy_density', 'mebibyte', 'length', + 'acceleration_due_to_gravity', 'planck_temperature', 'tebi', 'inch', + 'electronvolt', 'coulomb_constant', 'kelvin', 'kPa', 'boltzmann', + 'milli_mass_unit', 'gibi', 'planck_impedance', 'electric_constant', 'kg', + 'coulomb', 'siemens', 'byte', 'atomic_mass_unit', 'm', 'kibibyte', + 'kilogram', 'lightyear', 'mass', 'time', 'pebibyte', 'velocity', + 'ampere', 'katal', +] diff --git a/lib/python3.12/site-packages/sympy/physics/units/systems/mks.py b/lib/python3.12/site-packages/sympy/physics/units/systems/mks.py new file mode 100644 index 0000000000000000000000000000000000000000..18cc4b1be5e2cbf5773845e48a0cb552fb750fae --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/systems/mks.py @@ -0,0 +1,46 @@ +""" +MKS unit system. + +MKS stands for "meter, kilogram, second". +""" + +from sympy.physics.units import UnitSystem +from sympy.physics.units.definitions import gravitational_constant, hertz, joule, newton, pascal, watt, speed_of_light, gram, kilogram, meter, second +from sympy.physics.units.definitions.dimension_definitions import ( + acceleration, action, energy, force, frequency, momentum, + power, pressure, velocity, length, mass, time) +from sympy.physics.units.prefixes import PREFIXES, prefix_unit +from sympy.physics.units.systems.length_weight_time import dimsys_length_weight_time + +dims = (velocity, acceleration, momentum, force, energy, power, pressure, + frequency, action) + +units = [meter, gram, second, joule, newton, watt, pascal, hertz] +all_units = [] + +# Prefixes of units like gram, joule, newton etc get added using `prefix_unit` +# in the for loop, but the actual units have to be added manually. +all_units.extend([gram, joule, newton, watt, pascal, hertz]) + +for u in units: + all_units.extend(prefix_unit(u, PREFIXES)) +all_units.extend([gravitational_constant, speed_of_light]) + +# unit system +MKS = UnitSystem(base_units=(meter, kilogram, second), units=all_units, name="MKS", dimension_system=dimsys_length_weight_time, derived_units={ + power: watt, + time: second, + pressure: pascal, + length: meter, + frequency: hertz, + mass: kilogram, + force: newton, + energy: joule, + velocity: meter/second, + acceleration: meter/(second**2), +}) + + +__all__ = [ + 'MKS', 'units', 'all_units', 'dims', +] diff --git a/lib/python3.12/site-packages/sympy/physics/units/systems/mksa.py b/lib/python3.12/site-packages/sympy/physics/units/systems/mksa.py new file mode 100644 index 0000000000000000000000000000000000000000..c18c0d6ae3801358d8828e2309d091cb9cb987d8 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/systems/mksa.py @@ -0,0 +1,54 @@ +""" +MKS unit system. + +MKS stands for "meter, kilogram, second, ampere". +""" + +from __future__ import annotations + +from sympy.physics.units.definitions import Z0, ampere, coulomb, farad, henry, siemens, tesla, volt, weber, ohm +from sympy.physics.units.definitions.dimension_definitions import ( + capacitance, charge, conductance, current, impedance, inductance, + magnetic_density, magnetic_flux, voltage) +from sympy.physics.units.prefixes import PREFIXES, prefix_unit +from sympy.physics.units.systems.mks import MKS, dimsys_length_weight_time +from sympy.physics.units.quantities import Quantity + +dims = (voltage, impedance, conductance, current, capacitance, inductance, charge, + magnetic_density, magnetic_flux) + +units = [ampere, volt, ohm, siemens, farad, henry, coulomb, tesla, weber] + +all_units: list[Quantity] = [] +for u in units: + all_units.extend(prefix_unit(u, PREFIXES)) +all_units.extend(units) + +all_units.append(Z0) + +dimsys_MKSA = dimsys_length_weight_time.extend([ + # Dimensional dependencies for base dimensions (MKSA not in MKS) + current, +], new_dim_deps={ + # Dimensional dependencies for derived dimensions + "voltage": {"mass": 1, "length": 2, "current": -1, "time": -3}, + "impedance": {"mass": 1, "length": 2, "current": -2, "time": -3}, + "conductance": {"mass": -1, "length": -2, "current": 2, "time": 3}, + "capacitance": {"mass": -1, "length": -2, "current": 2, "time": 4}, + "inductance": {"mass": 1, "length": 2, "current": -2, "time": -2}, + "charge": {"current": 1, "time": 1}, + "magnetic_density": {"mass": 1, "current": -1, "time": -2}, + "magnetic_flux": {"length": 2, "mass": 1, "current": -1, "time": -2}, +}) + +MKSA = MKS.extend(base=(ampere,), units=all_units, name='MKSA', dimension_system=dimsys_MKSA, derived_units={ + magnetic_flux: weber, + impedance: ohm, + current: ampere, + voltage: volt, + inductance: henry, + conductance: siemens, + magnetic_density: tesla, + charge: coulomb, + capacitance: farad, +}) diff --git a/lib/python3.12/site-packages/sympy/physics/units/systems/natural.py b/lib/python3.12/site-packages/sympy/physics/units/systems/natural.py new file mode 100644 index 0000000000000000000000000000000000000000..13eb2c19e982438fab4b1422ddc5a25b16204be8 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/systems/natural.py @@ -0,0 +1,27 @@ +""" +Naturalunit system. + +The natural system comes from "setting c = 1, hbar = 1". From the computer +point of view it means that we use velocity and action instead of length and +time. Moreover instead of mass we use energy. +""" + +from sympy.physics.units import DimensionSystem +from sympy.physics.units.definitions import c, eV, hbar +from sympy.physics.units.definitions.dimension_definitions import ( + action, energy, force, frequency, length, mass, momentum, + power, time, velocity) +from sympy.physics.units.prefixes import PREFIXES, prefix_unit +from sympy.physics.units.unitsystem import UnitSystem + + +# dimension system +_natural_dim = DimensionSystem( + base_dims=(action, energy, velocity), + derived_dims=(length, mass, time, momentum, force, power, frequency) +) + +units = prefix_unit(eV, PREFIXES) + +# unit system +natural = UnitSystem(base_units=(hbar, eV, c), units=units, name="Natural system") diff --git a/lib/python3.12/site-packages/sympy/physics/units/systems/si.py b/lib/python3.12/site-packages/sympy/physics/units/systems/si.py new file mode 100644 index 0000000000000000000000000000000000000000..2bfa7805871b8663c70b8af7da9ca1dc9b4afab3 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/systems/si.py @@ -0,0 +1,377 @@ +""" +SI unit system. +Based on MKSA, which stands for "meter, kilogram, second, ampere". +Added kelvin, candela and mole. + +""" + +from __future__ import annotations + +from sympy.physics.units import DimensionSystem, Dimension, dHg0 + +from sympy.physics.units.quantities import Quantity + +from sympy.core.numbers import (Rational, pi) +from sympy.core.singleton import S +from sympy.functions.elementary.miscellaneous import sqrt +from sympy.physics.units.definitions.dimension_definitions import ( + acceleration, action, current, impedance, length, mass, time, velocity, + amount_of_substance, temperature, information, frequency, force, pressure, + energy, power, charge, voltage, capacitance, conductance, magnetic_flux, + magnetic_density, inductance, luminous_intensity +) +from sympy.physics.units.definitions import ( + kilogram, newton, second, meter, gram, cd, K, joule, watt, pascal, hertz, + coulomb, volt, ohm, siemens, farad, henry, tesla, weber, dioptre, lux, + katal, gray, becquerel, inch, liter, julian_year, gravitational_constant, + speed_of_light, elementary_charge, planck, hbar, electronvolt, + avogadro_number, avogadro_constant, boltzmann_constant, electron_rest_mass, + stefan_boltzmann_constant, Da, atomic_mass_constant, molar_gas_constant, + faraday_constant, josephson_constant, von_klitzing_constant, + acceleration_due_to_gravity, magnetic_constant, vacuum_permittivity, + vacuum_impedance, coulomb_constant, atmosphere, bar, pound, psi, mmHg, + milli_mass_unit, quart, lightyear, astronomical_unit, planck_mass, + planck_time, planck_temperature, planck_length, planck_charge, planck_area, + planck_volume, planck_momentum, planck_energy, planck_force, planck_power, + planck_density, planck_energy_density, planck_intensity, + planck_angular_frequency, planck_pressure, planck_current, planck_voltage, + planck_impedance, planck_acceleration, bit, byte, kibibyte, mebibyte, + gibibyte, tebibyte, pebibyte, exbibyte, curie, rutherford, radian, degree, + steradian, angular_mil, atomic_mass_unit, gee, kPa, ampere, u0, c, kelvin, + mol, mole, candela, m, kg, s, electric_constant, G, boltzmann +) +from sympy.physics.units.prefixes import PREFIXES, prefix_unit +from sympy.physics.units.systems.mksa import MKSA, dimsys_MKSA + +derived_dims = (frequency, force, pressure, energy, power, charge, voltage, + capacitance, conductance, magnetic_flux, + magnetic_density, inductance, luminous_intensity) +base_dims = (amount_of_substance, luminous_intensity, temperature) + +units = [mol, cd, K, lux, hertz, newton, pascal, joule, watt, coulomb, volt, + farad, ohm, siemens, weber, tesla, henry, candela, lux, becquerel, + gray, katal] + +all_units: list[Quantity] = [] +for u in units: + all_units.extend(prefix_unit(u, PREFIXES)) + +all_units.extend(units) +all_units.extend([mol, cd, K, lux]) + + +dimsys_SI = dimsys_MKSA.extend( + [ + # Dimensional dependencies for other base dimensions: + temperature, + amount_of_substance, + luminous_intensity, + ]) + +dimsys_default = dimsys_SI.extend( + [information], +) + +SI = MKSA.extend(base=(mol, cd, K), units=all_units, name='SI', dimension_system=dimsys_SI, derived_units={ + power: watt, + magnetic_flux: weber, + time: second, + impedance: ohm, + pressure: pascal, + current: ampere, + voltage: volt, + length: meter, + frequency: hertz, + inductance: henry, + temperature: kelvin, + amount_of_substance: mole, + luminous_intensity: candela, + conductance: siemens, + mass: kilogram, + magnetic_density: tesla, + charge: coulomb, + force: newton, + capacitance: farad, + energy: joule, + velocity: meter/second, +}) + +One = S.One + +SI.set_quantity_dimension(radian, One) + +SI.set_quantity_scale_factor(ampere, One) + +SI.set_quantity_scale_factor(kelvin, One) + +SI.set_quantity_scale_factor(mole, One) + +SI.set_quantity_scale_factor(candela, One) + +# MKSA extension to MKS: derived units + +SI.set_quantity_scale_factor(coulomb, One) + +SI.set_quantity_scale_factor(volt, joule/coulomb) + +SI.set_quantity_scale_factor(ohm, volt/ampere) + +SI.set_quantity_scale_factor(siemens, ampere/volt) + +SI.set_quantity_scale_factor(farad, coulomb/volt) + +SI.set_quantity_scale_factor(henry, volt*second/ampere) + +SI.set_quantity_scale_factor(tesla, volt*second/meter**2) + +SI.set_quantity_scale_factor(weber, joule/ampere) + + +SI.set_quantity_dimension(lux, luminous_intensity / length ** 2) +SI.set_quantity_scale_factor(lux, steradian*candela/meter**2) + +# katal is the SI unit of catalytic activity + +SI.set_quantity_dimension(katal, amount_of_substance / time) +SI.set_quantity_scale_factor(katal, mol/second) + +# gray is the SI unit of absorbed dose + +SI.set_quantity_dimension(gray, energy / mass) +SI.set_quantity_scale_factor(gray, meter**2/second**2) + +# becquerel is the SI unit of radioactivity + +SI.set_quantity_dimension(becquerel, 1 / time) +SI.set_quantity_scale_factor(becquerel, 1/second) + +#### CONSTANTS #### + +# elementary charge +# REF: NIST SP 959 (June 2019) + +SI.set_quantity_dimension(elementary_charge, charge) +SI.set_quantity_scale_factor(elementary_charge, 1.602176634e-19*coulomb) + +# Electronvolt +# REF: NIST SP 959 (June 2019) + +SI.set_quantity_dimension(electronvolt, energy) +SI.set_quantity_scale_factor(electronvolt, 1.602176634e-19*joule) + +# Avogadro number +# REF: NIST SP 959 (June 2019) + +SI.set_quantity_dimension(avogadro_number, One) +SI.set_quantity_scale_factor(avogadro_number, 6.02214076e23) + +# Avogadro constant + +SI.set_quantity_dimension(avogadro_constant, amount_of_substance ** -1) +SI.set_quantity_scale_factor(avogadro_constant, avogadro_number / mol) + +# Boltzmann constant +# REF: NIST SP 959 (June 2019) + +SI.set_quantity_dimension(boltzmann_constant, energy / temperature) +SI.set_quantity_scale_factor(boltzmann_constant, 1.380649e-23*joule/kelvin) + +# Stefan-Boltzmann constant +# REF: NIST SP 959 (June 2019) + +SI.set_quantity_dimension(stefan_boltzmann_constant, energy * time ** -1 * length ** -2 * temperature ** -4) +SI.set_quantity_scale_factor(stefan_boltzmann_constant, pi**2 * boltzmann_constant**4 / (60 * hbar**3 * speed_of_light ** 2)) + +# Atomic mass +# REF: NIST SP 959 (June 2019) + +SI.set_quantity_dimension(atomic_mass_constant, mass) +SI.set_quantity_scale_factor(atomic_mass_constant, 1.66053906660e-24*gram) + +# Molar gas constant +# REF: NIST SP 959 (June 2019) + +SI.set_quantity_dimension(molar_gas_constant, energy / (temperature * amount_of_substance)) +SI.set_quantity_scale_factor(molar_gas_constant, boltzmann_constant * avogadro_constant) + +# Faraday constant + +SI.set_quantity_dimension(faraday_constant, charge / amount_of_substance) +SI.set_quantity_scale_factor(faraday_constant, elementary_charge * avogadro_constant) + +# Josephson constant + +SI.set_quantity_dimension(josephson_constant, frequency / voltage) +SI.set_quantity_scale_factor(josephson_constant, 0.5 * planck / elementary_charge) + +# Von Klitzing constant + +SI.set_quantity_dimension(von_klitzing_constant, voltage / current) +SI.set_quantity_scale_factor(von_klitzing_constant, hbar / elementary_charge ** 2) + +# Acceleration due to gravity (on the Earth surface) + +SI.set_quantity_dimension(acceleration_due_to_gravity, acceleration) +SI.set_quantity_scale_factor(acceleration_due_to_gravity, 9.80665*meter/second**2) + +# magnetic constant: + +SI.set_quantity_dimension(magnetic_constant, force / current ** 2) +SI.set_quantity_scale_factor(magnetic_constant, 4*pi/10**7 * newton/ampere**2) + +# electric constant: + +SI.set_quantity_dimension(vacuum_permittivity, capacitance / length) +SI.set_quantity_scale_factor(vacuum_permittivity, 1/(u0 * c**2)) + +# vacuum impedance: + +SI.set_quantity_dimension(vacuum_impedance, impedance) +SI.set_quantity_scale_factor(vacuum_impedance, u0 * c) + +# Electron rest mass +SI.set_quantity_dimension(electron_rest_mass, mass) +SI.set_quantity_scale_factor(electron_rest_mass, 9.1093837015e-31*kilogram) + +# Coulomb's constant: +SI.set_quantity_dimension(coulomb_constant, force * length ** 2 / charge ** 2) +SI.set_quantity_scale_factor(coulomb_constant, 1/(4*pi*vacuum_permittivity)) + +SI.set_quantity_dimension(psi, pressure) +SI.set_quantity_scale_factor(psi, pound * gee / inch ** 2) + +SI.set_quantity_dimension(mmHg, pressure) +SI.set_quantity_scale_factor(mmHg, dHg0 * acceleration_due_to_gravity * kilogram / meter**2) + +SI.set_quantity_dimension(milli_mass_unit, mass) +SI.set_quantity_scale_factor(milli_mass_unit, atomic_mass_unit/1000) + +SI.set_quantity_dimension(quart, length ** 3) +SI.set_quantity_scale_factor(quart, Rational(231, 4) * inch**3) + +# Other convenient units and magnitudes + +SI.set_quantity_dimension(lightyear, length) +SI.set_quantity_scale_factor(lightyear, speed_of_light*julian_year) + +SI.set_quantity_dimension(astronomical_unit, length) +SI.set_quantity_scale_factor(astronomical_unit, 149597870691*meter) + +# Fundamental Planck units: + +SI.set_quantity_dimension(planck_mass, mass) +SI.set_quantity_scale_factor(planck_mass, sqrt(hbar*speed_of_light/G)) + +SI.set_quantity_dimension(planck_time, time) +SI.set_quantity_scale_factor(planck_time, sqrt(hbar*G/speed_of_light**5)) + +SI.set_quantity_dimension(planck_temperature, temperature) +SI.set_quantity_scale_factor(planck_temperature, sqrt(hbar*speed_of_light**5/G/boltzmann**2)) + +SI.set_quantity_dimension(planck_length, length) +SI.set_quantity_scale_factor(planck_length, sqrt(hbar*G/speed_of_light**3)) + +SI.set_quantity_dimension(planck_charge, charge) +SI.set_quantity_scale_factor(planck_charge, sqrt(4*pi*electric_constant*hbar*speed_of_light)) + +# Derived Planck units: + +SI.set_quantity_dimension(planck_area, length ** 2) +SI.set_quantity_scale_factor(planck_area, planck_length**2) + +SI.set_quantity_dimension(planck_volume, length ** 3) +SI.set_quantity_scale_factor(planck_volume, planck_length**3) + +SI.set_quantity_dimension(planck_momentum, mass * velocity) +SI.set_quantity_scale_factor(planck_momentum, planck_mass * speed_of_light) + +SI.set_quantity_dimension(planck_energy, energy) +SI.set_quantity_scale_factor(planck_energy, planck_mass * speed_of_light**2) + +SI.set_quantity_dimension(planck_force, force) +SI.set_quantity_scale_factor(planck_force, planck_energy / planck_length) + +SI.set_quantity_dimension(planck_power, power) +SI.set_quantity_scale_factor(planck_power, planck_energy / planck_time) + +SI.set_quantity_dimension(planck_density, mass / length ** 3) +SI.set_quantity_scale_factor(planck_density, planck_mass / planck_length**3) + +SI.set_quantity_dimension(planck_energy_density, energy / length ** 3) +SI.set_quantity_scale_factor(planck_energy_density, planck_energy / planck_length**3) + +SI.set_quantity_dimension(planck_intensity, mass * time ** (-3)) +SI.set_quantity_scale_factor(planck_intensity, planck_energy_density * speed_of_light) + +SI.set_quantity_dimension(planck_angular_frequency, 1 / time) +SI.set_quantity_scale_factor(planck_angular_frequency, 1 / planck_time) + +SI.set_quantity_dimension(planck_pressure, pressure) +SI.set_quantity_scale_factor(planck_pressure, planck_force / planck_length**2) + +SI.set_quantity_dimension(planck_current, current) +SI.set_quantity_scale_factor(planck_current, planck_charge / planck_time) + +SI.set_quantity_dimension(planck_voltage, voltage) +SI.set_quantity_scale_factor(planck_voltage, planck_energy / planck_charge) + +SI.set_quantity_dimension(planck_impedance, impedance) +SI.set_quantity_scale_factor(planck_impedance, planck_voltage / planck_current) + +SI.set_quantity_dimension(planck_acceleration, acceleration) +SI.set_quantity_scale_factor(planck_acceleration, speed_of_light / planck_time) + +# Older units for radioactivity + +SI.set_quantity_dimension(curie, 1 / time) +SI.set_quantity_scale_factor(curie, 37000000000*becquerel) + +SI.set_quantity_dimension(rutherford, 1 / time) +SI.set_quantity_scale_factor(rutherford, 1000000*becquerel) + + +# check that scale factors are the right SI dimensions: +for _scale_factor, _dimension in zip( + SI._quantity_scale_factors.values(), + SI._quantity_dimension_map.values() +): + dimex = SI.get_dimensional_expr(_scale_factor) + if dimex != 1: + # XXX: equivalent_dims is an instance method taking two arguments in + # addition to self so this can not work: + if not DimensionSystem.equivalent_dims(_dimension, Dimension(dimex)): # type: ignore + raise ValueError("quantity value and dimension mismatch") +del _scale_factor, _dimension + +__all__ = [ + 'mmHg', 'atmosphere', 'inductance', 'newton', 'meter', + 'vacuum_permittivity', 'pascal', 'magnetic_constant', 'voltage', + 'angular_mil', 'luminous_intensity', 'all_units', + 'julian_year', 'weber', 'exbibyte', 'liter', + 'molar_gas_constant', 'faraday_constant', 'avogadro_constant', + 'lightyear', 'planck_density', 'gee', 'mol', 'bit', 'gray', + 'planck_momentum', 'bar', 'magnetic_density', 'prefix_unit', 'PREFIXES', + 'planck_time', 'dimex', 'gram', 'candela', 'force', 'planck_intensity', + 'energy', 'becquerel', 'planck_acceleration', 'speed_of_light', + 'conductance', 'frequency', 'coulomb_constant', 'degree', 'lux', 'planck', + 'current', 'planck_current', 'tebibyte', 'planck_power', 'MKSA', 'power', + 'K', 'planck_volume', 'quart', 'pressure', 'amount_of_substance', + 'joule', 'boltzmann_constant', 'Dimension', 'c', 'planck_force', 'length', + 'watt', 'action', 'hbar', 'gibibyte', 'DimensionSystem', 'cd', 'volt', + 'planck_charge', 'dioptre', 'vacuum_impedance', 'dimsys_default', 'farad', + 'charge', 'gravitational_constant', 'temperature', 'u0', 'hertz', + 'capacitance', 'tesla', 'steradian', 'planck_mass', 'josephson_constant', + 'planck_area', 'stefan_boltzmann_constant', 'base_dims', + 'astronomical_unit', 'radian', 'planck_voltage', 'impedance', + 'planck_energy', 'Da', 'atomic_mass_constant', 'rutherford', 'second', 'inch', + 'elementary_charge', 'SI', 'electronvolt', 'dimsys_SI', 'henry', + 'planck_angular_frequency', 'ohm', 'pound', 'planck_pressure', 'G', 'psi', + 'dHg0', 'von_klitzing_constant', 'planck_length', 'avogadro_number', + 'mole', 'acceleration', 'information', 'planck_energy_density', + 'mebibyte', 's', 'acceleration_due_to_gravity', 'electron_rest_mass', + 'planck_temperature', 'units', 'mass', 'dimsys_MKSA', 'kelvin', 'kPa', + 'boltzmann', 'milli_mass_unit', 'planck_impedance', 'electric_constant', + 'derived_dims', 'kg', 'coulomb', 'siemens', 'byte', 'magnetic_flux', + 'atomic_mass_unit', 'm', 'kibibyte', 'kilogram', 'One', 'curie', 'u', + 'time', 'pebibyte', 'velocity', 'ampere', 'katal', +] diff --git a/lib/python3.12/site-packages/sympy/physics/units/tests/__init__.py b/lib/python3.12/site-packages/sympy/physics/units/tests/__init__.py new file mode 100644 index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 diff 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b/lib/python3.12/site-packages/sympy/physics/units/tests/test_dimensions.py new file mode 100644 index 0000000000000000000000000000000000000000..6455df41068a07c966c5f3e782e561fec4d16a97 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/tests/test_dimensions.py @@ -0,0 +1,150 @@ +from sympy.physics.units.systems.si import dimsys_SI + +from sympy.core.numbers import pi +from sympy.core.singleton import S +from sympy.core.symbol import Symbol +from sympy.functions.elementary.complexes import Abs +from sympy.functions.elementary.exponential import log +from sympy.functions.elementary.miscellaneous import sqrt +from sympy.functions.elementary.trigonometric import (acos, atan2, cos) +from sympy.physics.units.dimensions import Dimension +from sympy.physics.units.definitions.dimension_definitions import ( + length, time, mass, force, pressure, angle +) +from sympy.physics.units import foot +from sympy.testing.pytest import raises + + +def test_Dimension_definition(): + assert dimsys_SI.get_dimensional_dependencies(length) == {length: 1} + assert length.name == Symbol("length") + assert length.symbol == Symbol("L") + + halflength = sqrt(length) + assert dimsys_SI.get_dimensional_dependencies(halflength) == {length: S.Half} + + +def test_Dimension_error_definition(): + # tuple with more or less than two entries + raises(TypeError, lambda: Dimension(("length", 1, 2))) + raises(TypeError, lambda: Dimension(["length"])) + + # non-number power + raises(TypeError, lambda: Dimension({"length": "a"})) + + # non-number with named argument + raises(TypeError, lambda: Dimension({"length": (1, 2)})) + + # symbol should by Symbol or str + raises(AssertionError, lambda: Dimension("length", symbol=1)) + + +def test_str(): + assert str(Dimension("length")) == "Dimension(length)" + assert str(Dimension("length", "L")) == "Dimension(length, L)" + + +def test_Dimension_properties(): + assert dimsys_SI.is_dimensionless(length) is False + assert dimsys_SI.is_dimensionless(length/length) is True + assert dimsys_SI.is_dimensionless(Dimension("undefined")) is False + + assert length.has_integer_powers(dimsys_SI) is True + assert (length**(-1)).has_integer_powers(dimsys_SI) is True + assert (length**1.5).has_integer_powers(dimsys_SI) is False + + +def test_Dimension_add_sub(): + assert length + length == length + assert length - length == length + assert -length == length + + raises(TypeError, lambda: length + foot) + raises(TypeError, lambda: foot + length) + raises(TypeError, lambda: length - foot) + raises(TypeError, lambda: foot - length) + + # issue 14547 - only raise error for dimensional args; allow + # others to pass + x = Symbol('x') + e = length + x + assert e == x + length and e.is_Add and set(e.args) == {length, x} + e = length + 1 + assert e == 1 + length == 1 - length and e.is_Add and set(e.args) == {length, 1} + + assert dimsys_SI.get_dimensional_dependencies(mass * length / time**2 + force) == \ + {length: 1, mass: 1, time: -2} + assert dimsys_SI.get_dimensional_dependencies(mass * length / time**2 + force - + pressure * length**2) == \ + {length: 1, mass: 1, time: -2} + + raises(TypeError, lambda: dimsys_SI.get_dimensional_dependencies(mass * length / time**2 + pressure)) + +def test_Dimension_mul_div_exp(): + assert 2*length == length*2 == length/2 == length + assert 2/length == 1/length + x = Symbol('x') + m = x*length + assert m == length*x and m.is_Mul and set(m.args) == {x, length} + d = x/length + assert d == x*length**-1 and d.is_Mul and set(d.args) == {x, 1/length} + d = length/x + assert d == length*x**-1 and d.is_Mul and set(d.args) == {1/x, length} + + velo = length / time + + assert (length * length) == length ** 2 + + assert dimsys_SI.get_dimensional_dependencies(length * length) == {length: 2} + assert dimsys_SI.get_dimensional_dependencies(length ** 2) == {length: 2} + assert dimsys_SI.get_dimensional_dependencies(length * time) == {length: 1, time: 1} + assert dimsys_SI.get_dimensional_dependencies(velo) == {length: 1, time: -1} + assert dimsys_SI.get_dimensional_dependencies(velo ** 2) == {length: 2, time: -2} + + assert dimsys_SI.get_dimensional_dependencies(length / length) == {} + assert dimsys_SI.get_dimensional_dependencies(velo / length * time) == {} + assert dimsys_SI.get_dimensional_dependencies(length ** -1) == {length: -1} + assert dimsys_SI.get_dimensional_dependencies(velo ** -1.5) == {length: -1.5, time: 1.5} + + length_a = length**"a" + assert dimsys_SI.get_dimensional_dependencies(length_a) == {length: Symbol("a")} + + assert dimsys_SI.get_dimensional_dependencies(length**pi) == {length: pi} + assert dimsys_SI.get_dimensional_dependencies(length**(length/length)) == {length: Dimension(1)} + + raises(TypeError, lambda: dimsys_SI.get_dimensional_dependencies(length**length)) + + assert length != 1 + assert length / length != 1 + + length_0 = length ** 0 + assert dimsys_SI.get_dimensional_dependencies(length_0) == {} + + # issue 18738 + a = Symbol('a') + b = Symbol('b') + c = sqrt(a**2 + b**2) + c_dim = c.subs({a: length, b: length}) + assert dimsys_SI.equivalent_dims(c_dim, length) + +def test_Dimension_functions(): + raises(TypeError, lambda: dimsys_SI.get_dimensional_dependencies(cos(length))) + raises(TypeError, lambda: dimsys_SI.get_dimensional_dependencies(acos(angle))) + raises(TypeError, lambda: dimsys_SI.get_dimensional_dependencies(atan2(length, time))) + raises(TypeError, lambda: dimsys_SI.get_dimensional_dependencies(log(length))) + raises(TypeError, lambda: dimsys_SI.get_dimensional_dependencies(log(100, length))) + raises(TypeError, lambda: dimsys_SI.get_dimensional_dependencies(log(length, 10))) + + assert dimsys_SI.get_dimensional_dependencies(pi) == {} + + assert dimsys_SI.get_dimensional_dependencies(cos(1)) == {} + assert dimsys_SI.get_dimensional_dependencies(cos(angle)) == {} + + assert dimsys_SI.get_dimensional_dependencies(atan2(length, length)) == {} + + assert dimsys_SI.get_dimensional_dependencies(log(length / length, length / length)) == {} + + assert dimsys_SI.get_dimensional_dependencies(Abs(length)) == {length: 1} + assert dimsys_SI.get_dimensional_dependencies(Abs(length / length)) == {} + + assert dimsys_SI.get_dimensional_dependencies(sqrt(-1)) == {} diff --git a/lib/python3.12/site-packages/sympy/physics/units/tests/test_dimensionsystem.py b/lib/python3.12/site-packages/sympy/physics/units/tests/test_dimensionsystem.py new file mode 100644 index 0000000000000000000000000000000000000000..8a55ac398c38adf24d93bfa376c9cc51c1ec40fe --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/tests/test_dimensionsystem.py @@ -0,0 +1,95 @@ +from sympy.core.symbol import symbols +from sympy.matrices.dense import (Matrix, eye) +from sympy.physics.units.definitions.dimension_definitions import ( + action, current, length, mass, time, + velocity) +from sympy.physics.units.dimensions import DimensionSystem + + +def test_extend(): + ms = DimensionSystem((length, time), (velocity,)) + + mks = ms.extend((mass,), (action,)) + + res = DimensionSystem((length, time, mass), (velocity, action)) + assert mks.base_dims == res.base_dims + assert mks.derived_dims == res.derived_dims + + +def test_list_dims(): + dimsys = DimensionSystem((length, time, mass)) + + assert dimsys.list_can_dims == (length, mass, time) + + +def test_dim_can_vector(): + dimsys = DimensionSystem( + [length, mass, time], + [velocity, action], + { + velocity: {length: 1, time: -1} + } + ) + + assert dimsys.dim_can_vector(length) == Matrix([1, 0, 0]) + assert dimsys.dim_can_vector(velocity) == Matrix([1, 0, -1]) + + dimsys = DimensionSystem( + (length, velocity, action), + (mass, time), + { + time: {length: 1, velocity: -1} + } + ) + + assert dimsys.dim_can_vector(length) == Matrix([0, 1, 0]) + assert dimsys.dim_can_vector(velocity) == Matrix([0, 0, 1]) + assert dimsys.dim_can_vector(time) == Matrix([0, 1, -1]) + + dimsys = DimensionSystem( + (length, mass, time), + (velocity, action), + {velocity: {length: 1, time: -1}, + action: {mass: 1, length: 2, time: -1}}) + + assert dimsys.dim_vector(length) == Matrix([1, 0, 0]) + assert dimsys.dim_vector(velocity) == Matrix([1, 0, -1]) + + +def test_inv_can_transf_matrix(): + dimsys = DimensionSystem((length, mass, time)) + assert dimsys.inv_can_transf_matrix == eye(3) + + +def test_can_transf_matrix(): + dimsys = DimensionSystem((length, mass, time)) + assert dimsys.can_transf_matrix == eye(3) + + dimsys = DimensionSystem((length, velocity, action)) + assert dimsys.can_transf_matrix == eye(3) + + dimsys = DimensionSystem((length, time), (velocity,), {velocity: {length: 1, time: -1}}) + assert dimsys.can_transf_matrix == eye(2) + + +def test_is_consistent(): + assert DimensionSystem((length, time)).is_consistent is True + + +def test_print_dim_base(): + mksa = DimensionSystem( + (length, time, mass, current), + (action,), + {action: {mass: 1, length: 2, time: -1}}) + L, M, T = symbols("L M T") + assert mksa.print_dim_base(action) == L**2*M/T + + +def test_dim(): + dimsys = DimensionSystem( + (length, mass, time), + (velocity, action), + {velocity: {length: 1, time: -1}, + action: {mass: 1, length: 2, time: -1}} + ) + assert dimsys.dim == 3 diff --git a/lib/python3.12/site-packages/sympy/physics/units/tests/test_prefixes.py b/lib/python3.12/site-packages/sympy/physics/units/tests/test_prefixes.py new file mode 100644 index 0000000000000000000000000000000000000000..7b180102ecd00abf3ff5f8cb4c24aa82ae76ef77 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/tests/test_prefixes.py @@ -0,0 +1,86 @@ +from sympy.core.mul import Mul +from sympy.core.numbers import Rational +from sympy.core.singleton import S +from sympy.core.symbol import (Symbol, symbols) +from sympy.physics.units import Quantity, length, meter, W +from sympy.physics.units.prefixes import PREFIXES, Prefix, prefix_unit, kilo, \ + kibi +from sympy.physics.units.systems import SI + +x = Symbol('x') + + +def test_prefix_operations(): + m = PREFIXES['m'] + k = PREFIXES['k'] + M = PREFIXES['M'] + + dodeca = Prefix('dodeca', 'dd', 1, base=12) + + assert m * k is S.One + assert m * W == W / 1000 + assert k * k == M + assert 1 / m == k + assert k / m == M + + assert dodeca * dodeca == 144 + assert 1 / dodeca == S.One / 12 + assert k / dodeca == S(1000) / 12 + assert dodeca / dodeca is S.One + + m = Quantity("fake_meter") + SI.set_quantity_dimension(m, S.One) + SI.set_quantity_scale_factor(m, S.One) + + assert dodeca * m == 12 * m + assert dodeca / m == 12 / m + + expr1 = kilo * 3 + assert isinstance(expr1, Mul) + assert expr1.args == (3, kilo) + + expr2 = kilo * x + assert isinstance(expr2, Mul) + assert expr2.args == (x, kilo) + + expr3 = kilo / 3 + assert isinstance(expr3, Mul) + assert expr3.args == (Rational(1, 3), kilo) + assert expr3.args == (S.One/3, kilo) + + expr4 = kilo / x + assert isinstance(expr4, Mul) + assert expr4.args == (1/x, kilo) + + +def test_prefix_unit(): + m = Quantity("fake_meter", abbrev="m") + m.set_global_relative_scale_factor(1, meter) + + pref = {"m": PREFIXES["m"], "c": PREFIXES["c"], "d": PREFIXES["d"]} + + q1 = Quantity("millifake_meter", abbrev="mm") + q2 = Quantity("centifake_meter", abbrev="cm") + q3 = Quantity("decifake_meter", abbrev="dm") + + SI.set_quantity_dimension(q1, length) + + SI.set_quantity_scale_factor(q1, PREFIXES["m"]) + SI.set_quantity_scale_factor(q1, PREFIXES["c"]) + SI.set_quantity_scale_factor(q1, PREFIXES["d"]) + + res = [q1, q2, q3] + + prefs = prefix_unit(m, pref) + assert set(prefs) == set(res) + assert {v.abbrev for v in prefs} == set(symbols("mm,cm,dm")) + + +def test_bases(): + assert kilo.base == 10 + assert kibi.base == 2 + + +def test_repr(): + assert eval(repr(kilo)) == kilo + assert eval(repr(kibi)) == kibi diff --git a/lib/python3.12/site-packages/sympy/physics/units/tests/test_quantities.py b/lib/python3.12/site-packages/sympy/physics/units/tests/test_quantities.py new file mode 100644 index 0000000000000000000000000000000000000000..4e24ca48cc858bd8afd0b3c9762c4f8b6d0c5194 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/tests/test_quantities.py @@ -0,0 +1,575 @@ +import warnings + +from sympy.core.add import Add +from sympy.core.function import (Function, diff) +from sympy.core.numbers import (Number, Rational) +from sympy.core.singleton import S +from sympy.core.symbol import (Symbol, symbols) +from sympy.functions.elementary.complexes import Abs +from sympy.functions.elementary.exponential import (exp, log) +from sympy.functions.elementary.miscellaneous import sqrt +from sympy.functions.elementary.trigonometric import sin +from sympy.integrals.integrals import integrate +from sympy.physics.units import (amount_of_substance, area, convert_to, find_unit, + volume, kilometer, joule, molar_gas_constant, + vacuum_permittivity, elementary_charge, volt, + ohm) +from sympy.physics.units.definitions import (amu, au, centimeter, coulomb, + day, foot, grams, hour, inch, kg, km, m, meter, millimeter, + minute, quart, s, second, speed_of_light, bit, + byte, kibibyte, mebibyte, gibibyte, tebibyte, pebibyte, exbibyte, + kilogram, gravitational_constant, electron_rest_mass) + +from sympy.physics.units.definitions.dimension_definitions import ( + Dimension, charge, length, time, temperature, pressure, + energy, mass +) +from sympy.physics.units.prefixes import PREFIXES, kilo +from sympy.physics.units.quantities import PhysicalConstant, Quantity +from sympy.physics.units.systems import SI +from sympy.testing.pytest import raises + +k = PREFIXES["k"] + + +def test_str_repr(): + assert str(kg) == "kilogram" + + +def test_eq(): + # simple test + assert 10*m == 10*m + assert 10*m != 10*s + + +def test_convert_to(): + q = Quantity("q1") + q.set_global_relative_scale_factor(S(5000), meter) + + assert q.convert_to(m) == 5000*m + + assert speed_of_light.convert_to(m / s) == 299792458 * m / s + assert day.convert_to(s) == 86400*s + + # Wrong dimension to convert: + assert q.convert_to(s) == q + assert speed_of_light.convert_to(m) == speed_of_light + + expr = joule*second + conv = convert_to(expr, joule) + assert conv == joule*second + + +def test_Quantity_definition(): + q = Quantity("s10", abbrev="sabbr") + q.set_global_relative_scale_factor(10, second) + u = Quantity("u", abbrev="dam") + u.set_global_relative_scale_factor(10, meter) + km = Quantity("km") + km.set_global_relative_scale_factor(kilo, meter) + v = Quantity("u") + v.set_global_relative_scale_factor(5*kilo, meter) + + assert q.scale_factor == 10 + assert q.dimension == time + assert q.abbrev == Symbol("sabbr") + + assert u.dimension == length + assert u.scale_factor == 10 + assert u.abbrev == Symbol("dam") + + assert km.scale_factor == 1000 + assert km.func(*km.args) == km + assert km.func(*km.args).args == km.args + + assert v.dimension == length + assert v.scale_factor == 5000 + + +def test_abbrev(): + u = Quantity("u") + u.set_global_relative_scale_factor(S.One, meter) + + assert u.name == Symbol("u") + assert u.abbrev == Symbol("u") + + u = Quantity("u", abbrev="om") + u.set_global_relative_scale_factor(S(2), meter) + + assert u.name == Symbol("u") + assert u.abbrev == Symbol("om") + assert u.scale_factor == 2 + assert isinstance(u.scale_factor, Number) + + u = Quantity("u", abbrev="ikm") + u.set_global_relative_scale_factor(3*kilo, meter) + + assert u.abbrev == Symbol("ikm") + assert u.scale_factor == 3000 + + +def test_print(): + u = Quantity("unitname", abbrev="dam") + assert repr(u) == "unitname" + assert str(u) == "unitname" + + +def test_Quantity_eq(): + u = Quantity("u", abbrev="dam") + v = Quantity("v1") + assert u != v + v = Quantity("v2", abbrev="ds") + assert u != v + v = Quantity("v3", abbrev="dm") + assert u != v + + +def test_add_sub(): + u = Quantity("u") + v = Quantity("v") + w = Quantity("w") + + u.set_global_relative_scale_factor(S(10), meter) + v.set_global_relative_scale_factor(S(5), meter) + w.set_global_relative_scale_factor(S(2), second) + + assert isinstance(u + v, Add) + assert (u + v.convert_to(u)) == (1 + S.Half)*u + assert isinstance(u - v, Add) + assert (u - v.convert_to(u)) == S.Half*u + + +def test_quantity_abs(): + v_w1 = Quantity('v_w1') + v_w2 = Quantity('v_w2') + v_w3 = Quantity('v_w3') + + v_w1.set_global_relative_scale_factor(1, meter/second) + v_w2.set_global_relative_scale_factor(1, meter/second) + v_w3.set_global_relative_scale_factor(1, meter/second) + + expr = v_w3 - Abs(v_w1 - v_w2) + + assert SI.get_dimensional_expr(v_w1) == (length/time).name + + Dq = Dimension(SI.get_dimensional_expr(expr)) + + assert SI.get_dimension_system().get_dimensional_dependencies(Dq) == { + length: 1, + time: -1, + } + assert meter == sqrt(meter**2) + + +def test_check_unit_consistency(): + u = Quantity("u") + v = Quantity("v") + w = Quantity("w") + + u.set_global_relative_scale_factor(S(10), meter) + v.set_global_relative_scale_factor(S(5), meter) + w.set_global_relative_scale_factor(S(2), second) + + def check_unit_consistency(expr): + SI._collect_factor_and_dimension(expr) + + raises(ValueError, lambda: check_unit_consistency(u + w)) + raises(ValueError, lambda: check_unit_consistency(u - w)) + raises(ValueError, lambda: check_unit_consistency(u + 1)) + raises(ValueError, lambda: check_unit_consistency(u - 1)) + raises(ValueError, lambda: check_unit_consistency(1 - exp(u / w))) + + +def test_mul_div(): + u = Quantity("u") + v = Quantity("v") + t = Quantity("t") + ut = Quantity("ut") + v2 = Quantity("v") + + u.set_global_relative_scale_factor(S(10), meter) + v.set_global_relative_scale_factor(S(5), meter) + t.set_global_relative_scale_factor(S(2), second) + ut.set_global_relative_scale_factor(S(20), meter*second) + v2.set_global_relative_scale_factor(S(5), meter/second) + + assert 1 / u == u**(-1) + assert u / 1 == u + + v1 = u / t + v2 = v + + # Pow only supports structural equality: + assert v1 != v2 + assert v1 == v2.convert_to(v1) + + # TODO: decide whether to allow such expression in the future + # (requires somehow manipulating the core). + # assert u / Quantity('l2', dimension=length, scale_factor=2) == 5 + + assert u * 1 == u + + ut1 = u * t + ut2 = ut + + # Mul only supports structural equality: + assert ut1 != ut2 + assert ut1 == ut2.convert_to(ut1) + + # Mul only supports structural equality: + lp1 = Quantity("lp1") + lp1.set_global_relative_scale_factor(S(2), 1/meter) + assert u * lp1 != 20 + + assert u**0 == 1 + assert u**1 == u + + # TODO: Pow only support structural equality: + u2 = Quantity("u2") + u3 = Quantity("u3") + u2.set_global_relative_scale_factor(S(100), meter**2) + u3.set_global_relative_scale_factor(Rational(1, 10), 1/meter) + + assert u ** 2 != u2 + assert u ** -1 != u3 + + assert u ** 2 == u2.convert_to(u) + assert u ** -1 == u3.convert_to(u) + + +def test_units(): + assert convert_to((5*m/s * day) / km, 1) == 432 + assert convert_to(foot / meter, meter) == Rational(3048, 10000) + # amu is a pure mass so mass/mass gives a number, not an amount (mol) + # TODO: need better simplification routine: + assert str(convert_to(grams/amu, grams).n(2)) == '6.0e+23' + + # Light from the sun needs about 8.3 minutes to reach earth + t = (1*au / speed_of_light) / minute + # TODO: need a better way to simplify expressions containing units: + t = convert_to(convert_to(t, meter / minute), meter) + assert t.simplify() == Rational(49865956897, 5995849160) + + # TODO: fix this, it should give `m` without `Abs` + assert sqrt(m**2) == m + assert (sqrt(m))**2 == m + + t = Symbol('t') + assert integrate(t*m/s, (t, 1*s, 5*s)) == 12*m*s + assert (t * m/s).integrate((t, 1*s, 5*s)) == 12*m*s + + +def test_issue_quart(): + assert convert_to(4 * quart / inch ** 3, meter) == 231 + assert convert_to(4 * quart / inch ** 3, millimeter) == 231 + +def test_electron_rest_mass(): + assert convert_to(electron_rest_mass, kilogram) == 9.1093837015e-31*kilogram + assert convert_to(electron_rest_mass, grams) == 9.1093837015e-28*grams + +def test_issue_5565(): + assert (m < s).is_Relational + + +def test_find_unit(): + assert find_unit('coulomb') == ['coulomb', 'coulombs', 'coulomb_constant'] + assert find_unit(coulomb) == ['C', 'coulomb', 'coulombs', 'planck_charge', 'elementary_charge'] + assert find_unit(charge) == ['C', 'coulomb', 'coulombs', 'planck_charge', 'elementary_charge'] + assert find_unit(inch) == [ + 'm', 'au', 'cm', 'dm', 'ft', 'km', 'ly', 'mi', 'mm', 'nm', 'pm', 'um', 'yd', + 'nmi', 'feet', 'foot', 'inch', 'mile', 'yard', 'meter', 'miles', 'yards', + 'inches', 'meters', 'micron', 'microns', 'angstrom', 'angstroms', 'decimeter', + 'kilometer', 'lightyear', 'nanometer', 'picometer', 'centimeter', 'decimeters', + 'kilometers', 'lightyears', 'micrometer', 'millimeter', 'nanometers', 'picometers', + 'centimeters', 'micrometers', 'millimeters', 'nautical_mile', 'planck_length', + 'nautical_miles', 'astronomical_unit', 'astronomical_units'] + assert find_unit(inch**-1) == ['D', 'dioptre', 'optical_power'] + assert find_unit(length**-1) == ['D', 'dioptre', 'optical_power'] + assert find_unit(inch ** 2) == ['ha', 'hectare', 'planck_area'] + assert find_unit(inch ** 3) == [ + 'L', 'l', 'cL', 'cl', 'dL', 'dl', 'mL', 'ml', 'liter', 'quart', 'liters', 'quarts', + 'deciliter', 'centiliter', 'deciliters', 'milliliter', + 'centiliters', 'milliliters', 'planck_volume'] + assert find_unit('voltage') == ['V', 'v', 'volt', 'volts', 'planck_voltage'] + assert find_unit(grams) == ['g', 't', 'Da', 'kg', 'me', 'mg', 'ug', 'amu', 'mmu', 'amus', + 'gram', 'mmus', 'grams', 'pound', 'tonne', 'dalton', 'pounds', + 'kilogram', 'kilograms', 'microgram', 'milligram', 'metric_ton', + 'micrograms', 'milligrams', 'planck_mass', 'milli_mass_unit', 'atomic_mass_unit', + 'electron_rest_mass', 'atomic_mass_constant'] + + +def test_Quantity_derivative(): + x = symbols("x") + assert diff(x*meter, x) == meter + assert diff(x**3*meter**2, x) == 3*x**2*meter**2 + assert diff(meter, meter) == 1 + assert diff(meter**2, meter) == 2*meter + + +def test_quantity_postprocessing(): + q1 = Quantity('q1') + q2 = Quantity('q2') + + SI.set_quantity_dimension(q1, length*pressure**2*temperature/time) + SI.set_quantity_dimension(q2, energy*pressure*temperature/(length**2*time)) + + assert q1 + q2 + q = q1 + q2 + Dq = Dimension(SI.get_dimensional_expr(q)) + assert SI.get_dimension_system().get_dimensional_dependencies(Dq) == { + length: -1, + mass: 2, + temperature: 1, + time: -5, + } + + +def test_factor_and_dimension(): + assert (3000, Dimension(1)) == SI._collect_factor_and_dimension(3000) + assert (1001, length) == SI._collect_factor_and_dimension(meter + km) + assert (2, length/time) == SI._collect_factor_and_dimension( + meter/second + 36*km/(10*hour)) + + x, y = symbols('x y') + assert (x + y/100, length) == SI._collect_factor_and_dimension( + x*m + y*centimeter) + + cH = Quantity('cH') + SI.set_quantity_dimension(cH, amount_of_substance/volume) + + pH = -log(cH) + + assert (1, volume/amount_of_substance) == SI._collect_factor_and_dimension( + exp(pH)) + + v_w1 = Quantity('v_w1') + v_w2 = Quantity('v_w2') + + v_w1.set_global_relative_scale_factor(Rational(3, 2), meter/second) + v_w2.set_global_relative_scale_factor(2, meter/second) + + expr = Abs(v_w1/2 - v_w2) + assert (Rational(5, 4), length/time) == \ + SI._collect_factor_and_dimension(expr) + + expr = Rational(5, 2)*second/meter*v_w1 - 3000 + assert (-(2996 + Rational(1, 4)), Dimension(1)) == \ + SI._collect_factor_and_dimension(expr) + + expr = v_w1**(v_w2/v_w1) + assert ((Rational(3, 2))**Rational(4, 3), (length/time)**Rational(4, 3)) == \ + SI._collect_factor_and_dimension(expr) + + +def test_dimensional_expr_of_derivative(): + l = Quantity('l') + t = Quantity('t') + t1 = Quantity('t1') + l.set_global_relative_scale_factor(36, km) + t.set_global_relative_scale_factor(1, hour) + t1.set_global_relative_scale_factor(1, second) + x = Symbol('x') + y = Symbol('y') + f = Function('f') + dfdx = f(x, y).diff(x, y) + dl_dt = dfdx.subs({f(x, y): l, x: t, y: t1}) + assert SI.get_dimensional_expr(dl_dt) ==\ + SI.get_dimensional_expr(l / t / t1) ==\ + Symbol("length")/Symbol("time")**2 + assert SI._collect_factor_and_dimension(dl_dt) ==\ + SI._collect_factor_and_dimension(l / t / t1) ==\ + (10, length/time**2) + + +def test_get_dimensional_expr_with_function(): + v_w1 = Quantity('v_w1') + v_w2 = Quantity('v_w2') + v_w1.set_global_relative_scale_factor(1, meter/second) + v_w2.set_global_relative_scale_factor(1, meter/second) + + assert SI.get_dimensional_expr(sin(v_w1)) == \ + sin(SI.get_dimensional_expr(v_w1)) + assert SI.get_dimensional_expr(sin(v_w1/v_w2)) == 1 + + +def test_binary_information(): + assert convert_to(kibibyte, byte) == 1024*byte + assert convert_to(mebibyte, byte) == 1024**2*byte + assert convert_to(gibibyte, byte) == 1024**3*byte + assert convert_to(tebibyte, byte) == 1024**4*byte + assert convert_to(pebibyte, byte) == 1024**5*byte + assert convert_to(exbibyte, byte) == 1024**6*byte + + assert kibibyte.convert_to(bit) == 8*1024*bit + assert byte.convert_to(bit) == 8*bit + + a = 10*kibibyte*hour + + assert convert_to(a, byte) == 10240*byte*hour + assert convert_to(a, minute) == 600*kibibyte*minute + assert convert_to(a, [byte, minute]) == 614400*byte*minute + + +def test_conversion_with_2_nonstandard_dimensions(): + good_grade = Quantity("good_grade") + kilo_good_grade = Quantity("kilo_good_grade") + centi_good_grade = Quantity("centi_good_grade") + + kilo_good_grade.set_global_relative_scale_factor(1000, good_grade) + centi_good_grade.set_global_relative_scale_factor(S.One/10**5, kilo_good_grade) + + charity_points = Quantity("charity_points") + milli_charity_points = Quantity("milli_charity_points") + missions = Quantity("missions") + + milli_charity_points.set_global_relative_scale_factor(S.One/1000, charity_points) + missions.set_global_relative_scale_factor(251, charity_points) + + assert convert_to( + kilo_good_grade*milli_charity_points*millimeter, + [centi_good_grade, missions, centimeter] + ) == S.One * 10**5 / (251*1000) / 10 * centi_good_grade*missions*centimeter + + +def test_eval_subs(): + energy, mass, force = symbols('energy mass force') + expr1 = energy/mass + units = {energy: kilogram*meter**2/second**2, mass: kilogram} + assert expr1.subs(units) == meter**2/second**2 + expr2 = force/mass + units = {force:gravitational_constant*kilogram**2/meter**2, mass:kilogram} + assert expr2.subs(units) == gravitational_constant*kilogram/meter**2 + + +def test_issue_14932(): + assert (log(inch) - log(2)).simplify() == log(inch/2) + assert (log(inch) - log(foot)).simplify() == -log(12) + p = symbols('p', positive=True) + assert (log(inch) - log(p)).simplify() == log(inch/p) + + +def test_issue_14547(): + # the root issue is that an argument with dimensions should + # not raise an error when the `arg - 1` calculation is + # performed in the assumptions system + from sympy.physics.units import foot, inch + from sympy.core.relational import Eq + assert log(foot).is_zero is None + assert log(foot).is_positive is None + assert log(foot).is_nonnegative is None + assert log(foot).is_negative is None + assert log(foot).is_algebraic is None + assert log(foot).is_rational is None + # doesn't raise error + assert Eq(log(foot), log(inch)) is not None # might be False or unevaluated + + x = Symbol('x') + e = foot + x + assert e.is_Add and set(e.args) == {foot, x} + e = foot + 1 + assert e.is_Add and set(e.args) == {foot, 1} + + +def test_issue_22164(): + warnings.simplefilter("error") + dm = Quantity("dm") + SI.set_quantity_dimension(dm, length) + SI.set_quantity_scale_factor(dm, 1) + + bad_exp = Quantity("bad_exp") + SI.set_quantity_dimension(bad_exp, length) + SI.set_quantity_scale_factor(bad_exp, 1) + + expr = dm ** bad_exp + + # deprecation warning is not expected here + SI._collect_factor_and_dimension(expr) + + +def test_issue_22819(): + from sympy.physics.units import tonne, gram, Da + from sympy.physics.units.systems.si import dimsys_SI + assert tonne.convert_to(gram) == 1000000*gram + assert dimsys_SI.get_dimensional_dependencies(area) == {length: 2} + assert Da.scale_factor == 1.66053906660000e-24 + + +def test_issue_20288(): + from sympy.core.numbers import E + from sympy.physics.units import energy + u = Quantity('u') + v = Quantity('v') + SI.set_quantity_dimension(u, energy) + SI.set_quantity_dimension(v, energy) + u.set_global_relative_scale_factor(1, joule) + v.set_global_relative_scale_factor(1, joule) + expr = 1 + exp(u**2/v**2) + assert SI._collect_factor_and_dimension(expr) == (1 + E, Dimension(1)) + + +def test_issue_24062(): + from sympy.core.numbers import E + from sympy.physics.units import impedance, capacitance, time, ohm, farad, second + + R = Quantity('R') + C = Quantity('C') + T = Quantity('T') + SI.set_quantity_dimension(R, impedance) + SI.set_quantity_dimension(C, capacitance) + SI.set_quantity_dimension(T, time) + R.set_global_relative_scale_factor(1, ohm) + C.set_global_relative_scale_factor(1, farad) + T.set_global_relative_scale_factor(1, second) + expr = T / (R * C) + dim = SI._collect_factor_and_dimension(expr)[1] + assert SI.get_dimension_system().is_dimensionless(dim) + + exp_expr = 1 + exp(expr) + assert SI._collect_factor_and_dimension(exp_expr) == (1 + E, Dimension(1)) + +def test_issue_24211(): + from sympy.physics.units import time, velocity, acceleration, second, meter + V1 = Quantity('V1') + SI.set_quantity_dimension(V1, velocity) + SI.set_quantity_scale_factor(V1, 1 * meter / second) + A1 = Quantity('A1') + SI.set_quantity_dimension(A1, acceleration) + SI.set_quantity_scale_factor(A1, 1 * meter / second**2) + T1 = Quantity('T1') + SI.set_quantity_dimension(T1, time) + SI.set_quantity_scale_factor(T1, 1 * second) + + expr = A1*T1 + V1 + # should not throw ValueError here + SI._collect_factor_and_dimension(expr) + + +def test_prefixed_property(): + assert not meter.is_prefixed + assert not joule.is_prefixed + assert not day.is_prefixed + assert not second.is_prefixed + assert not volt.is_prefixed + assert not ohm.is_prefixed + assert centimeter.is_prefixed + assert kilometer.is_prefixed + assert kilogram.is_prefixed + assert pebibyte.is_prefixed + +def test_physics_constant(): + from sympy.physics.units import definitions + + for name in dir(definitions): + quantity = getattr(definitions, name) + if not isinstance(quantity, Quantity): + continue + if name.endswith('_constant'): + assert isinstance(quantity, PhysicalConstant), f"{quantity} must be PhysicalConstant, but is {type(quantity)}" + assert quantity.is_physical_constant, f"{name} is not marked as physics constant when it should be" + + for const in [gravitational_constant, molar_gas_constant, vacuum_permittivity, speed_of_light, elementary_charge]: + assert isinstance(const, PhysicalConstant), f"{const} must be PhysicalConstant, but is {type(const)}" + assert const.is_physical_constant, f"{const} is not marked as physics constant when it should be" + + assert not meter.is_physical_constant + assert not joule.is_physical_constant diff --git a/lib/python3.12/site-packages/sympy/physics/units/tests/test_unit_system_cgs_gauss.py b/lib/python3.12/site-packages/sympy/physics/units/tests/test_unit_system_cgs_gauss.py new file mode 100644 index 0000000000000000000000000000000000000000..12629280785c94fa8be33bc97bdd714140a3e346 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/tests/test_unit_system_cgs_gauss.py @@ -0,0 +1,55 @@ +from sympy.concrete.tests.test_sums_products import NS + +from sympy.core.singleton import S +from sympy.functions.elementary.miscellaneous import sqrt +from sympy.physics.units import convert_to, coulomb_constant, elementary_charge, gravitational_constant, planck +from sympy.physics.units.definitions.unit_definitions import angstrom, statcoulomb, coulomb, second, gram, centimeter, erg, \ + newton, joule, dyne, speed_of_light, meter, farad, henry, statvolt, volt, ohm +from sympy.physics.units.systems import SI +from sympy.physics.units.systems.cgs import cgs_gauss + + +def test_conversion_to_from_si(): + assert convert_to(statcoulomb, coulomb, cgs_gauss) == coulomb/2997924580 + assert convert_to(coulomb, statcoulomb, cgs_gauss) == 2997924580*statcoulomb + assert convert_to(statcoulomb, sqrt(gram*centimeter**3)/second, cgs_gauss) == centimeter**(S(3)/2)*sqrt(gram)/second + assert convert_to(coulomb, sqrt(gram*centimeter**3)/second, cgs_gauss) == 2997924580*centimeter**(S(3)/2)*sqrt(gram)/second + + # SI units have an additional base unit, no conversion in case of electromagnetism: + assert convert_to(coulomb, statcoulomb, SI) == coulomb + assert convert_to(statcoulomb, coulomb, SI) == statcoulomb + + # SI without electromagnetism: + assert convert_to(erg, joule, SI) == joule/10**7 + assert convert_to(erg, joule, cgs_gauss) == joule/10**7 + assert convert_to(joule, erg, SI) == 10**7*erg + assert convert_to(joule, erg, cgs_gauss) == 10**7*erg + + + assert convert_to(dyne, newton, SI) == newton/10**5 + assert convert_to(dyne, newton, cgs_gauss) == newton/10**5 + assert convert_to(newton, dyne, SI) == 10**5*dyne + assert convert_to(newton, dyne, cgs_gauss) == 10**5*dyne + + +def test_cgs_gauss_convert_constants(): + + assert convert_to(speed_of_light, centimeter/second, cgs_gauss) == 29979245800*centimeter/second + + assert convert_to(coulomb_constant, 1, cgs_gauss) == 1 + assert convert_to(coulomb_constant, newton*meter**2/coulomb**2, cgs_gauss) == 22468879468420441*meter**2*newton/(2500000*coulomb**2) + assert convert_to(coulomb_constant, newton*meter**2/coulomb**2, SI) == 22468879468420441*meter**2*newton/(2500000*coulomb**2) + assert convert_to(coulomb_constant, dyne*centimeter**2/statcoulomb**2, cgs_gauss) == centimeter**2*dyne/statcoulomb**2 + assert convert_to(coulomb_constant, 1, SI) == coulomb_constant + assert NS(convert_to(coulomb_constant, newton*meter**2/coulomb**2, SI)) == '8987551787.36818*meter**2*newton/coulomb**2' + + assert convert_to(elementary_charge, statcoulomb, cgs_gauss) + assert convert_to(angstrom, centimeter, cgs_gauss) == 1*centimeter/10**8 + assert convert_to(gravitational_constant, dyne*centimeter**2/gram**2, cgs_gauss) + assert NS(convert_to(planck, erg*second, cgs_gauss)) == '6.62607015e-27*erg*second' + + spc = 25000*second/(22468879468420441*centimeter) + assert convert_to(ohm, second/centimeter, cgs_gauss) == spc + assert convert_to(henry, second**2/centimeter, cgs_gauss) == spc*second + assert convert_to(volt, statvolt, cgs_gauss) == 10**6*statvolt/299792458 + assert convert_to(farad, centimeter, cgs_gauss) == 299792458**2*centimeter/10**5 diff --git a/lib/python3.12/site-packages/sympy/physics/units/tests/test_unitsystem.py b/lib/python3.12/site-packages/sympy/physics/units/tests/test_unitsystem.py new file mode 100644 index 0000000000000000000000000000000000000000..a04f3aabb6274bed4f1b82ac0719fa618b55eed7 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/tests/test_unitsystem.py @@ -0,0 +1,86 @@ +from sympy.physics.units import DimensionSystem, joule, second, ampere + +from sympy.core.numbers import Rational +from sympy.core.singleton import S +from sympy.physics.units.definitions import c, kg, m, s +from sympy.physics.units.definitions.dimension_definitions import length, time +from sympy.physics.units.quantities import Quantity +from sympy.physics.units.unitsystem import UnitSystem +from sympy.physics.units.util import convert_to + + +def test_definition(): + # want to test if the system can have several units of the same dimension + dm = Quantity("dm") + base = (m, s) + # base_dim = (m.dimension, s.dimension) + ms = UnitSystem(base, (c, dm), "MS", "MS system") + ms.set_quantity_dimension(dm, length) + ms.set_quantity_scale_factor(dm, Rational(1, 10)) + + assert set(ms._base_units) == set(base) + assert set(ms._units) == {m, s, c, dm} + # assert ms._units == DimensionSystem._sort_dims(base + (velocity,)) + assert ms.name == "MS" + assert ms.descr == "MS system" + + +def test_str_repr(): + assert str(UnitSystem((m, s), name="MS")) == "MS" + assert str(UnitSystem((m, s))) == "UnitSystem((meter, second))" + + assert repr(UnitSystem((m, s))) == "" % (m, s) + + +def test_convert_to(): + A = Quantity("A") + A.set_global_relative_scale_factor(S.One, ampere) + + Js = Quantity("Js") + Js.set_global_relative_scale_factor(S.One, joule*second) + + mksa = UnitSystem((m, kg, s, A), (Js,)) + assert convert_to(Js, mksa._base_units) == m**2*kg*s**-1/1000 + + +def test_extend(): + ms = UnitSystem((m, s), (c,)) + Js = Quantity("Js") + Js.set_global_relative_scale_factor(1, joule*second) + mks = ms.extend((kg,), (Js,)) + + res = UnitSystem((m, s, kg), (c, Js)) + assert set(mks._base_units) == set(res._base_units) + assert set(mks._units) == set(res._units) + + +def test_dim(): + dimsys = UnitSystem((m, kg, s), (c,)) + assert dimsys.dim == 3 + + +def test_is_consistent(): + dimension_system = DimensionSystem([length, time]) + us = UnitSystem([m, s], dimension_system=dimension_system) + assert us.is_consistent == True + + +def test_get_units_non_prefixed(): + from sympy.physics.units import volt, ohm + unit_system = UnitSystem.get_unit_system("SI") + units = unit_system.get_units_non_prefixed() + for prefix in ["giga", "tera", "peta", "exa", "zetta", "yotta", "kilo", "hecto", "deca", "deci", "centi", "milli", "micro", "nano", "pico", "femto", "atto", "zepto", "yocto"]: + for unit in units: + assert isinstance(unit, Quantity), f"{unit} must be a Quantity, not {type(unit)}" + assert not unit.is_prefixed, f"{unit} is marked as prefixed" + assert not unit.is_physical_constant, f"{unit} is marked as physics constant" + assert not unit.name.name.startswith(prefix), f"Unit {unit.name} has prefix {prefix}" + assert volt in units + assert ohm in units + +def test_derived_units_must_exist_in_unit_system(): + for unit_system in UnitSystem._unit_systems.values(): + for preferred_unit in unit_system.derived_units.values(): + units = preferred_unit.atoms(Quantity) + for unit in units: + assert unit in unit_system._units, f"Unit {unit} is not in unit system {unit_system}" diff --git a/lib/python3.12/site-packages/sympy/physics/units/tests/test_util.py b/lib/python3.12/site-packages/sympy/physics/units/tests/test_util.py new file mode 100644 index 0000000000000000000000000000000000000000..3522af675d33275f322e2b731309e19bffde1e1d --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/tests/test_util.py @@ -0,0 +1,178 @@ +from sympy.core.containers import Tuple +from sympy.core.numbers import pi +from sympy.core.power import Pow +from sympy.core.symbol import symbols +from sympy.core.sympify import sympify +from sympy.printing.str import sstr +from sympy.physics.units import ( + G, centimeter, coulomb, day, degree, gram, hbar, hour, inch, joule, kelvin, + kilogram, kilometer, length, meter, mile, minute, newton, planck, + planck_length, planck_mass, planck_temperature, planck_time, radians, + second, speed_of_light, steradian, time, km) +from sympy.physics.units.util import convert_to, check_dimensions +from sympy.testing.pytest import raises +from sympy.functions.elementary.miscellaneous import sqrt + + +def NS(e, n=15, **options): + return sstr(sympify(e).evalf(n, **options), full_prec=True) + + +L = length +T = time + + +def test_dim_simplify_add(): + # assert Add(L, L) == L + assert L + L == L + + +def test_dim_simplify_mul(): + # assert Mul(L, T) == L*T + assert L*T == L*T + + +def test_dim_simplify_pow(): + assert Pow(L, 2) == L**2 + + +def test_dim_simplify_rec(): + # assert Mul(Add(L, L), T) == L*T + assert (L + L) * T == L*T + + +def test_convert_to_quantities(): + assert convert_to(3, meter) == 3 + + assert convert_to(mile, kilometer) == 25146*kilometer/15625 + assert convert_to(meter/second, speed_of_light) == speed_of_light/299792458 + assert convert_to(299792458*meter/second, speed_of_light) == speed_of_light + assert convert_to(2*299792458*meter/second, speed_of_light) == 2*speed_of_light + assert convert_to(speed_of_light, meter/second) == 299792458*meter/second + assert convert_to(2*speed_of_light, meter/second) == 599584916*meter/second + assert convert_to(day, second) == 86400*second + assert convert_to(2*hour, minute) == 120*minute + assert convert_to(mile, meter) == 201168*meter/125 + assert convert_to(mile/hour, kilometer/hour) == 25146*kilometer/(15625*hour) + assert convert_to(3*newton, meter/second) == 3*newton + assert convert_to(3*newton, kilogram*meter/second**2) == 3*meter*kilogram/second**2 + assert convert_to(kilometer + mile, meter) == 326168*meter/125 + assert convert_to(2*kilometer + 3*mile, meter) == 853504*meter/125 + assert convert_to(inch**2, meter**2) == 16129*meter**2/25000000 + assert convert_to(3*inch**2, meter) == 48387*meter**2/25000000 + assert convert_to(2*kilometer/hour + 3*mile/hour, meter/second) == 53344*meter/(28125*second) + assert convert_to(2*kilometer/hour + 3*mile/hour, centimeter/second) == 213376*centimeter/(1125*second) + assert convert_to(kilometer * (mile + kilometer), meter) == 2609344 * meter ** 2 + + assert convert_to(steradian, coulomb) == steradian + assert convert_to(radians, degree) == 180*degree/pi + assert convert_to(radians, [meter, degree]) == 180*degree/pi + assert convert_to(pi*radians, degree) == 180*degree + assert convert_to(pi, degree) == 180*degree + + # https://github.com/sympy/sympy/issues/26263 + assert convert_to(sqrt(meter**2 + meter**2.0), meter) == sqrt(meter**2 + meter**2.0) + assert convert_to((meter**2 + meter**2.0)**2, meter) == (meter**2 + meter**2.0)**2 + + +def test_convert_to_tuples_of_quantities(): + from sympy.core.symbol import symbols + + alpha, beta = symbols('alpha beta') + + assert convert_to(speed_of_light, [meter, second]) == 299792458 * meter / second + assert convert_to(speed_of_light, (meter, second)) == 299792458 * meter / second + assert convert_to(speed_of_light, Tuple(meter, second)) == 299792458 * meter / second + assert convert_to(joule, [meter, kilogram, second]) == kilogram*meter**2/second**2 + assert convert_to(joule, [centimeter, gram, second]) == 10000000*centimeter**2*gram/second**2 + assert convert_to(299792458*meter/second, [speed_of_light]) == speed_of_light + assert convert_to(speed_of_light / 2, [meter, second, kilogram]) == meter/second*299792458 / 2 + # This doesn't make physically sense, but let's keep it as a conversion test: + assert convert_to(2 * speed_of_light, [meter, second, kilogram]) == 2 * 299792458 * meter / second + assert convert_to(G, [G, speed_of_light, planck]) == 1.0*G + + assert NS(convert_to(meter, [G, speed_of_light, hbar]), n=7) == '6.187142e+34*gravitational_constant**0.5000000*hbar**0.5000000/speed_of_light**1.500000' + assert NS(convert_to(planck_mass, kilogram), n=7) == '2.176434e-8*kilogram' + assert NS(convert_to(planck_length, meter), n=7) == '1.616255e-35*meter' + assert NS(convert_to(planck_time, second), n=6) == '5.39125e-44*second' + assert NS(convert_to(planck_temperature, kelvin), n=7) == '1.416784e+32*kelvin' + assert NS(convert_to(convert_to(meter, [G, speed_of_light, planck]), meter), n=10) == '1.000000000*meter' + + # similar to https://github.com/sympy/sympy/issues/26263 + assert convert_to(sqrt(meter**2 + second**2.0), [meter, second]) == sqrt(meter**2 + second**2.0) + assert convert_to((meter**2 + second**2.0)**2, [meter, second]) == (meter**2 + second**2.0)**2 + + # similar to https://github.com/sympy/sympy/issues/21463 + assert convert_to(1/(beta*meter + meter), 1/meter) == 1/(beta*meter + meter) + assert convert_to(1/(beta*meter + alpha*meter), 1/kilometer) == (1/(kilometer*beta/1000 + alpha*kilometer/1000)) + +def test_eval_simplify(): + from sympy.physics.units import cm, mm, km, m, K, kilo + from sympy.core.symbol import symbols + + x, y = symbols('x y') + + assert (cm/mm).simplify() == 10 + assert (km/m).simplify() == 1000 + assert (km/cm).simplify() == 100000 + assert (10*x*K*km**2/m/cm).simplify() == 1000000000*x*kelvin + assert (cm/km/m).simplify() == 1/(10000000*centimeter) + + assert (3*kilo*meter).simplify() == 3000*meter + assert (4*kilo*meter/(2*kilometer)).simplify() == 2 + assert (4*kilometer**2/(kilo*meter)**2).simplify() == 4 + + +def test_quantity_simplify(): + from sympy.physics.units.util import quantity_simplify + from sympy.physics.units import kilo, foot + from sympy.core.symbol import symbols + + x, y = symbols('x y') + + assert quantity_simplify(x*(8*kilo*newton*meter + y)) == x*(8000*meter*newton + y) + assert quantity_simplify(foot*inch*(foot + inch)) == foot**2*(foot + foot/12)/12 + assert quantity_simplify(foot*inch*(foot*foot + inch*(foot + inch))) == foot**2*(foot**2 + foot/12*(foot + foot/12))/12 + assert quantity_simplify(2**(foot/inch*kilo/1000)*inch) == 4096*foot/12 + assert quantity_simplify(foot**2*inch + inch**2*foot) == 13*foot**3/144 + +def test_quantity_simplify_across_dimensions(): + from sympy.physics.units.util import quantity_simplify + from sympy.physics.units import ampere, ohm, volt, joule, pascal, farad, second, watt, siemens, henry, tesla, weber, hour, newton + + assert quantity_simplify(ampere*ohm, across_dimensions=True, unit_system="SI") == volt + assert quantity_simplify(6*ampere*ohm, across_dimensions=True, unit_system="SI") == 6*volt + assert quantity_simplify(volt/ampere, across_dimensions=True, unit_system="SI") == ohm + assert quantity_simplify(volt/ohm, across_dimensions=True, unit_system="SI") == ampere + assert quantity_simplify(joule/meter**3, across_dimensions=True, unit_system="SI") == pascal + assert quantity_simplify(farad*ohm, across_dimensions=True, unit_system="SI") == second + assert quantity_simplify(joule/second, across_dimensions=True, unit_system="SI") == watt + assert quantity_simplify(meter**3/second, across_dimensions=True, unit_system="SI") == meter**3/second + assert quantity_simplify(joule/second, across_dimensions=True, unit_system="SI") == watt + + assert quantity_simplify(joule/coulomb, across_dimensions=True, unit_system="SI") == volt + assert quantity_simplify(volt/ampere, across_dimensions=True, unit_system="SI") == ohm + assert quantity_simplify(ampere/volt, across_dimensions=True, unit_system="SI") == siemens + assert quantity_simplify(coulomb/volt, across_dimensions=True, unit_system="SI") == farad + assert quantity_simplify(volt*second/ampere, across_dimensions=True, unit_system="SI") == henry + assert quantity_simplify(volt*second/meter**2, across_dimensions=True, unit_system="SI") == tesla + assert quantity_simplify(joule/ampere, across_dimensions=True, unit_system="SI") == weber + + assert quantity_simplify(5*kilometer/hour, across_dimensions=True, unit_system="SI") == 25*meter/(18*second) + assert quantity_simplify(5*kilogram*meter/second**2, across_dimensions=True, unit_system="SI") == 5*newton + +def test_check_dimensions(): + x = symbols('x') + assert check_dimensions(inch + x) == inch + x + assert check_dimensions(length + x) == length + x + # after subs we get 2*length; check will clear the constant + assert check_dimensions((length + x).subs(x, length)) == length + assert check_dimensions(newton*meter + joule) == joule + meter*newton + raises(ValueError, lambda: check_dimensions(inch + 1)) + raises(ValueError, lambda: check_dimensions(length + 1)) + raises(ValueError, lambda: check_dimensions(length + time)) + raises(ValueError, lambda: check_dimensions(meter + second)) + raises(ValueError, lambda: check_dimensions(2 * meter + second)) + raises(ValueError, lambda: check_dimensions(2 * meter + 3 * second)) + raises(ValueError, lambda: check_dimensions(1 / second + 1 / meter)) + raises(ValueError, lambda: check_dimensions(2 * meter*(mile + centimeter) + km)) diff --git a/lib/python3.12/site-packages/sympy/physics/units/unitsystem.py b/lib/python3.12/site-packages/sympy/physics/units/unitsystem.py new file mode 100644 index 0000000000000000000000000000000000000000..5705c821c217f781717f9dd5cad6f3c9c77b145f --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/unitsystem.py @@ -0,0 +1,205 @@ +""" +Unit system for physical quantities; include definition of constants. +""" + +from typing import Dict as tDict, Set as tSet + +from sympy.core.add import Add +from sympy.core.function import (Derivative, Function) +from sympy.core.mul import Mul +from sympy.core.power import Pow +from sympy.core.singleton import S +from sympy.physics.units.dimensions import _QuantityMapper +from sympy.physics.units.quantities import Quantity + +from .dimensions import Dimension + + +class UnitSystem(_QuantityMapper): + """ + UnitSystem represents a coherent set of units. + + A unit system is basically a dimension system with notions of scales. Many + of the methods are defined in the same way. + + It is much better if all base units have a symbol. + """ + + _unit_systems = {} # type: tDict[str, UnitSystem] + + def __init__(self, base_units, units=(), name="", descr="", dimension_system=None, derived_units: tDict[Dimension, Quantity]={}): + + UnitSystem._unit_systems[name] = self + + self.name = name + self.descr = descr + + self._base_units = base_units + self._dimension_system = dimension_system + self._units = tuple(set(base_units) | set(units)) + self._base_units = tuple(base_units) + self._derived_units = derived_units + + super().__init__() + + def __str__(self): + """ + Return the name of the system. + + If it does not exist, then it makes a list of symbols (or names) of + the base dimensions. + """ + + if self.name != "": + return self.name + else: + return "UnitSystem((%s))" % ", ".join( + str(d) for d in self._base_units) + + def __repr__(self): + return '' % repr(self._base_units) + + def extend(self, base, units=(), name="", description="", dimension_system=None, derived_units: tDict[Dimension, Quantity]={}): + """Extend the current system into a new one. + + Take the base and normal units of the current system to merge + them to the base and normal units given in argument. + If not provided, name and description are overridden by empty strings. + """ + + base = self._base_units + tuple(base) + units = self._units + tuple(units) + + return UnitSystem(base, units, name, description, dimension_system, {**self._derived_units, **derived_units}) + + def get_dimension_system(self): + return self._dimension_system + + def get_quantity_dimension(self, unit): + qdm = self.get_dimension_system()._quantity_dimension_map + if unit in qdm: + return qdm[unit] + return super().get_quantity_dimension(unit) + + def get_quantity_scale_factor(self, unit): + qsfm = self.get_dimension_system()._quantity_scale_factors + if unit in qsfm: + return qsfm[unit] + return super().get_quantity_scale_factor(unit) + + @staticmethod + def get_unit_system(unit_system): + if isinstance(unit_system, UnitSystem): + return unit_system + + if unit_system not in UnitSystem._unit_systems: + raise ValueError( + "Unit system is not supported. Currently" + "supported unit systems are {}".format( + ", ".join(sorted(UnitSystem._unit_systems)) + ) + ) + + return UnitSystem._unit_systems[unit_system] + + @staticmethod + def get_default_unit_system(): + return UnitSystem._unit_systems["SI"] + + @property + def dim(self): + """ + Give the dimension of the system. + + That is return the number of units forming the basis. + """ + return len(self._base_units) + + @property + def is_consistent(self): + """ + Check if the underlying dimension system is consistent. + """ + # test is performed in DimensionSystem + return self.get_dimension_system().is_consistent + + @property + def derived_units(self) -> tDict[Dimension, Quantity]: + return self._derived_units + + def get_dimensional_expr(self, expr): + from sympy.physics.units import Quantity + if isinstance(expr, Mul): + return Mul(*[self.get_dimensional_expr(i) for i in expr.args]) + elif isinstance(expr, Pow): + return self.get_dimensional_expr(expr.base) ** expr.exp + elif isinstance(expr, Add): + return self.get_dimensional_expr(expr.args[0]) + elif isinstance(expr, Derivative): + dim = self.get_dimensional_expr(expr.expr) + for independent, count in expr.variable_count: + dim /= self.get_dimensional_expr(independent)**count + return dim + elif isinstance(expr, Function): + args = [self.get_dimensional_expr(arg) for arg in expr.args] + if all(i == 1 for i in args): + return S.One + return expr.func(*args) + elif isinstance(expr, Quantity): + return self.get_quantity_dimension(expr).name + return S.One + + def _collect_factor_and_dimension(self, expr): + """ + Return tuple with scale factor expression and dimension expression. + """ + from sympy.physics.units import Quantity + if isinstance(expr, Quantity): + return expr.scale_factor, expr.dimension + elif isinstance(expr, Mul): + factor = 1 + dimension = Dimension(1) + for arg in expr.args: + arg_factor, arg_dim = self._collect_factor_and_dimension(arg) + factor *= arg_factor + dimension *= arg_dim + return factor, dimension + elif isinstance(expr, Pow): + factor, dim = self._collect_factor_and_dimension(expr.base) + exp_factor, exp_dim = self._collect_factor_and_dimension(expr.exp) + if self.get_dimension_system().is_dimensionless(exp_dim): + exp_dim = 1 + return factor ** exp_factor, dim ** (exp_factor * exp_dim) + elif isinstance(expr, Add): + factor, dim = self._collect_factor_and_dimension(expr.args[0]) + for addend in expr.args[1:]: + addend_factor, addend_dim = \ + self._collect_factor_and_dimension(addend) + if not self.get_dimension_system().equivalent_dims(dim, addend_dim): + raise ValueError( + 'Dimension of "{}" is {}, ' + 'but it should be {}'.format( + addend, addend_dim, dim)) + factor += addend_factor + return factor, dim + elif isinstance(expr, Derivative): + factor, dim = self._collect_factor_and_dimension(expr.args[0]) + for independent, count in expr.variable_count: + ifactor, idim = self._collect_factor_and_dimension(independent) + factor /= ifactor**count + dim /= idim**count + return factor, dim + elif isinstance(expr, Function): + fds = [self._collect_factor_and_dimension(arg) for arg in expr.args] + dims = [Dimension(1) if self.get_dimension_system().is_dimensionless(d[1]) else d[1] for d in fds] + return (expr.func(*(f[0] for f in fds)), *dims) + elif isinstance(expr, Dimension): + return S.One, expr + else: + return expr, Dimension(1) + + def get_units_non_prefixed(self) -> tSet[Quantity]: + """ + Return the units of the system that do not have a prefix. + """ + return set(filter(lambda u: not u.is_prefixed and not u.is_physical_constant, self._units)) diff --git a/lib/python3.12/site-packages/sympy/physics/units/util.py b/lib/python3.12/site-packages/sympy/physics/units/util.py new file mode 100644 index 0000000000000000000000000000000000000000..b3f5a004fe9fa93b11039c5a832829715a7d44c6 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/units/util.py @@ -0,0 +1,265 @@ +""" +Several methods to simplify expressions involving unit objects. +""" +from functools import reduce +from collections.abc import Iterable +from typing import Optional + +from sympy import default_sort_key +from sympy.core.add import Add +from sympy.core.containers import Tuple +from sympy.core.mul import Mul +from sympy.core.power import Pow +from sympy.core.sorting import ordered +from sympy.core.sympify import sympify +from sympy.core.function import Function +from sympy.matrices.exceptions import NonInvertibleMatrixError +from sympy.physics.units.dimensions import Dimension, DimensionSystem +from sympy.physics.units.prefixes import Prefix +from sympy.physics.units.quantities import Quantity +from sympy.physics.units.unitsystem import UnitSystem +from sympy.utilities.iterables import sift + + +def _get_conversion_matrix_for_expr(expr, target_units, unit_system): + from sympy.matrices.dense import Matrix + + dimension_system = unit_system.get_dimension_system() + + expr_dim = Dimension(unit_system.get_dimensional_expr(expr)) + dim_dependencies = dimension_system.get_dimensional_dependencies(expr_dim, mark_dimensionless=True) + target_dims = [Dimension(unit_system.get_dimensional_expr(x)) for x in target_units] + canon_dim_units = [i for x in target_dims for i in dimension_system.get_dimensional_dependencies(x, mark_dimensionless=True)] + canon_expr_units = set(dim_dependencies) + + if not canon_expr_units.issubset(set(canon_dim_units)): + return None + + seen = set() + canon_dim_units = [i for i in canon_dim_units if not (i in seen or seen.add(i))] + + camat = Matrix([[dimension_system.get_dimensional_dependencies(i, mark_dimensionless=True).get(j, 0) for i in target_dims] for j in canon_dim_units]) + exprmat = Matrix([dim_dependencies.get(k, 0) for k in canon_dim_units]) + + try: + res_exponents = camat.solve(exprmat) + except NonInvertibleMatrixError: + return None + + return res_exponents + + +def convert_to(expr, target_units, unit_system="SI"): + """ + Convert ``expr`` to the same expression with all of its units and quantities + represented as factors of ``target_units``, whenever the dimension is compatible. + + ``target_units`` may be a single unit/quantity, or a collection of + units/quantities. + + Examples + ======== + + >>> from sympy.physics.units import speed_of_light, meter, gram, second, day + >>> from sympy.physics.units import mile, newton, kilogram, atomic_mass_constant + >>> from sympy.physics.units import kilometer, centimeter + >>> from sympy.physics.units import gravitational_constant, hbar + >>> from sympy.physics.units import convert_to + >>> convert_to(mile, kilometer) + 25146*kilometer/15625 + >>> convert_to(mile, kilometer).n() + 1.609344*kilometer + >>> convert_to(speed_of_light, meter/second) + 299792458*meter/second + >>> convert_to(day, second) + 86400*second + >>> 3*newton + 3*newton + >>> convert_to(3*newton, kilogram*meter/second**2) + 3*kilogram*meter/second**2 + >>> convert_to(atomic_mass_constant, gram) + 1.660539060e-24*gram + + Conversion to multiple units: + + >>> convert_to(speed_of_light, [meter, second]) + 299792458*meter/second + >>> convert_to(3*newton, [centimeter, gram, second]) + 300000*centimeter*gram/second**2 + + Conversion to Planck units: + + >>> convert_to(atomic_mass_constant, [gravitational_constant, speed_of_light, hbar]).n() + 7.62963087839509e-20*hbar**0.5*speed_of_light**0.5/gravitational_constant**0.5 + + """ + from sympy.physics.units import UnitSystem + unit_system = UnitSystem.get_unit_system(unit_system) + + if not isinstance(target_units, (Iterable, Tuple)): + target_units = [target_units] + + def handle_Adds(expr): + return Add.fromiter(convert_to(i, target_units, unit_system) + for i in expr.args) + + if isinstance(expr, Add): + return handle_Adds(expr) + elif isinstance(expr, Pow) and isinstance(expr.base, Add): + return handle_Adds(expr.base) ** expr.exp + + expr = sympify(expr) + target_units = sympify(target_units) + + if isinstance(expr, Function): + expr = expr.together() + + if not isinstance(expr, Quantity) and expr.has(Quantity): + expr = expr.replace(lambda x: isinstance(x, Quantity), + lambda x: x.convert_to(target_units, unit_system)) + + def get_total_scale_factor(expr): + if isinstance(expr, Mul): + return reduce(lambda x, y: x * y, + [get_total_scale_factor(i) for i in expr.args]) + elif isinstance(expr, Pow): + return get_total_scale_factor(expr.base) ** expr.exp + elif isinstance(expr, Quantity): + return unit_system.get_quantity_scale_factor(expr) + return expr + + depmat = _get_conversion_matrix_for_expr(expr, target_units, unit_system) + if depmat is None: + return expr + + expr_scale_factor = get_total_scale_factor(expr) + return expr_scale_factor * Mul.fromiter( + (1/get_total_scale_factor(u)*u)**p for u, p in + zip(target_units, depmat)) + + +def quantity_simplify(expr, across_dimensions: bool=False, unit_system=None): + """Return an equivalent expression in which prefixes are replaced + with numerical values and all units of a given dimension are the + unified in a canonical manner by default. `across_dimensions` allows + for units of different dimensions to be simplified together. + + `unit_system` must be specified if `across_dimensions` is True. + + Examples + ======== + + >>> from sympy.physics.units.util import quantity_simplify + >>> from sympy.physics.units.prefixes import kilo + >>> from sympy.physics.units import foot, inch, joule, coulomb + >>> quantity_simplify(kilo*foot*inch) + 250*foot**2/3 + >>> quantity_simplify(foot - 6*inch) + foot/2 + >>> quantity_simplify(5*joule/coulomb, across_dimensions=True, unit_system="SI") + 5*volt + """ + + if expr.is_Atom or not expr.has(Prefix, Quantity): + return expr + + # replace all prefixes with numerical values + p = expr.atoms(Prefix) + expr = expr.xreplace({p: p.scale_factor for p in p}) + + # replace all quantities of given dimension with a canonical + # quantity, chosen from those in the expression + d = sift(expr.atoms(Quantity), lambda i: i.dimension) + for k in d: + if len(d[k]) == 1: + continue + v = list(ordered(d[k])) + ref = v[0]/v[0].scale_factor + expr = expr.xreplace({vi: ref*vi.scale_factor for vi in v[1:]}) + + if across_dimensions: + # combine quantities of different dimensions into a single + # quantity that is equivalent to the original expression + + if unit_system is None: + raise ValueError("unit_system must be specified if across_dimensions is True") + + unit_system = UnitSystem.get_unit_system(unit_system) + dimension_system: DimensionSystem = unit_system.get_dimension_system() + dim_expr = unit_system.get_dimensional_expr(expr) + dim_deps = dimension_system.get_dimensional_dependencies(dim_expr, mark_dimensionless=True) + + target_dimension: Optional[Dimension] = None + for ds_dim, ds_dim_deps in dimension_system.dimensional_dependencies.items(): + if ds_dim_deps == dim_deps: + target_dimension = ds_dim + break + + if target_dimension is None: + # if we can't find a target dimension, we can't do anything. unsure how to handle this case. + return expr + + target_unit = unit_system.derived_units.get(target_dimension) + if target_unit: + expr = convert_to(expr, target_unit, unit_system) + + return expr + + +def check_dimensions(expr, unit_system="SI"): + """Return expr if units in addends have the same + base dimensions, else raise a ValueError.""" + # the case of adding a number to a dimensional quantity + # is ignored for the sake of SymPy core routines, so this + # function will raise an error now if such an addend is + # found. + # Also, when doing substitutions, multiplicative constants + # might be introduced, so remove those now + + from sympy.physics.units import UnitSystem + unit_system = UnitSystem.get_unit_system(unit_system) + + def addDict(dict1, dict2): + """Merge dictionaries by adding values of common keys and + removing keys with value of 0.""" + dict3 = {**dict1, **dict2} + for key, value in dict3.items(): + if key in dict1 and key in dict2: + dict3[key] = value + dict1[key] + return {key:val for key, val in dict3.items() if val != 0} + + adds = expr.atoms(Add) + DIM_OF = unit_system.get_dimension_system().get_dimensional_dependencies + for a in adds: + deset = set() + for ai in a.args: + if ai.is_number: + deset.add(()) + continue + dims = [] + skip = False + dimdict = {} + for i in Mul.make_args(ai): + if i.has(Quantity): + i = Dimension(unit_system.get_dimensional_expr(i)) + if i.has(Dimension): + dimdict = addDict(dimdict, DIM_OF(i)) + elif i.free_symbols: + skip = True + break + dims.extend(dimdict.items()) + if not skip: + deset.add(tuple(sorted(dims, key=default_sort_key))) + if len(deset) > 1: + raise ValueError( + "addends have incompatible dimensions: {}".format(deset)) + + # clear multiplicative constants on Dimensions which may be + # left after substitution + reps = {} + for m in expr.atoms(Mul): + if any(isinstance(i, Dimension) for i in m.args): + reps[m] = m.func(*[ + i for i in m.args if not i.is_number]) + + return expr.xreplace(reps) diff --git a/lib/python3.12/site-packages/sympy/physics/vector/__init__.py b/lib/python3.12/site-packages/sympy/physics/vector/__init__.py new file mode 100644 index 0000000000000000000000000000000000000000..e714852064c0b940ebda2e5fe7a08faf13f07ed0 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/__init__.py @@ -0,0 +1,36 @@ +__all__ = [ + 'CoordinateSym', 'ReferenceFrame', + + 'Dyadic', + + 'Vector', + + 'Point', + + 'cross', 'dot', 'express', 'time_derivative', 'outer', + 'kinematic_equations', 'get_motion_params', 'partial_velocity', + 'dynamicsymbols', + + 'vprint', 'vsstrrepr', 'vsprint', 'vpprint', 'vlatex', 'init_vprinting', + + 'curl', 'divergence', 'gradient', 'is_conservative', 'is_solenoidal', + 'scalar_potential', 'scalar_potential_difference', + +] +from .frame import CoordinateSym, ReferenceFrame + +from .dyadic import Dyadic + +from .vector import Vector + +from .point import Point + +from .functions import (cross, dot, express, time_derivative, outer, + kinematic_equations, get_motion_params, partial_velocity, + dynamicsymbols) + +from .printing import (vprint, vsstrrepr, vsprint, vpprint, vlatex, + init_vprinting) + +from .fieldfunctions import (curl, divergence, gradient, is_conservative, + is_solenoidal, scalar_potential, scalar_potential_difference) diff --git a/lib/python3.12/site-packages/sympy/physics/vector/__pycache__/__init__.cpython-312.pyc b/lib/python3.12/site-packages/sympy/physics/vector/__pycache__/__init__.cpython-312.pyc new file mode 100644 index 0000000000000000000000000000000000000000..3c38e79d527b3a6fd2ba231bdd19a712b3a8f1d6 Binary files /dev/null and b/lib/python3.12/site-packages/sympy/physics/vector/__pycache__/__init__.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/vector/__pycache__/dyadic.cpython-312.pyc b/lib/python3.12/site-packages/sympy/physics/vector/__pycache__/dyadic.cpython-312.pyc new file mode 100644 index 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0000000000000000000000000000000000000000..514ab2312ba6e40c87a64c3a45f411e5d12a8015 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/dyadic.py @@ -0,0 +1,545 @@ +from sympy import sympify, Add, ImmutableMatrix as Matrix +from sympy.core.evalf import EvalfMixin +from sympy.printing.defaults import Printable + +from mpmath.libmp.libmpf import prec_to_dps + + +__all__ = ['Dyadic'] + + +class Dyadic(Printable, EvalfMixin): + """A Dyadic object. + + See: + https://en.wikipedia.org/wiki/Dyadic_tensor + Kane, T., Levinson, D. Dynamics Theory and Applications. 1985 McGraw-Hill + + A more powerful way to represent a rigid body's inertia. While it is more + complex, by choosing Dyadic components to be in body fixed basis vectors, + the resulting matrix is equivalent to the inertia tensor. + + """ + + is_number = False + + def __init__(self, inlist): + """ + Just like Vector's init, you should not call this unless creating a + zero dyadic. + + zd = Dyadic(0) + + Stores a Dyadic as a list of lists; the inner list has the measure + number and the two unit vectors; the outerlist holds each unique + unit vector pair. + + """ + + self.args = [] + if inlist == 0: + inlist = [] + while len(inlist) != 0: + added = 0 + for i, v in enumerate(self.args): + if ((str(inlist[0][1]) == str(self.args[i][1])) and + (str(inlist[0][2]) == str(self.args[i][2]))): + self.args[i] = (self.args[i][0] + inlist[0][0], + inlist[0][1], inlist[0][2]) + inlist.remove(inlist[0]) + added = 1 + break + if added != 1: + self.args.append(inlist[0]) + inlist.remove(inlist[0]) + i = 0 + # This code is to remove empty parts from the list + while i < len(self.args): + if ((self.args[i][0] == 0) | (self.args[i][1] == 0) | + (self.args[i][2] == 0)): + self.args.remove(self.args[i]) + i -= 1 + i += 1 + + @property + def func(self): + """Returns the class Dyadic. """ + return Dyadic + + def __add__(self, other): + """The add operator for Dyadic. """ + other = _check_dyadic(other) + return Dyadic(self.args + other.args) + + __radd__ = __add__ + + def __mul__(self, other): + """Multiplies the Dyadic by a sympifyable expression. + + Parameters + ========== + + other : Sympafiable + The scalar to multiply this Dyadic with + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, outer + >>> N = ReferenceFrame('N') + >>> d = outer(N.x, N.x) + >>> 5 * d + 5*(N.x|N.x) + + """ + newlist = list(self.args) + other = sympify(other) + for i, v in enumerate(newlist): + newlist[i] = (other * newlist[i][0], newlist[i][1], + newlist[i][2]) + return Dyadic(newlist) + + __rmul__ = __mul__ + + def dot(self, other): + """The inner product operator for a Dyadic and a Dyadic or Vector. + + Parameters + ========== + + other : Dyadic or Vector + The other Dyadic or Vector to take the inner product with + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, outer + >>> N = ReferenceFrame('N') + >>> D1 = outer(N.x, N.y) + >>> D2 = outer(N.y, N.y) + >>> D1.dot(D2) + (N.x|N.y) + >>> D1.dot(N.y) + N.x + + """ + from sympy.physics.vector.vector import Vector, _check_vector + if isinstance(other, Dyadic): + other = _check_dyadic(other) + ol = Dyadic(0) + for v in self.args: + for v2 in other.args: + ol += v[0] * v2[0] * (v[2].dot(v2[1])) * (v[1].outer(v2[2])) + else: + other = _check_vector(other) + ol = Vector(0) + for v in self.args: + ol += v[0] * v[1] * (v[2].dot(other)) + return ol + + # NOTE : supports non-advertised Dyadic & Dyadic, Dyadic & Vector notation + __and__ = dot + + def __truediv__(self, other): + """Divides the Dyadic by a sympifyable expression. """ + return self.__mul__(1 / other) + + def __eq__(self, other): + """Tests for equality. + + Is currently weak; needs stronger comparison testing + + """ + + if other == 0: + other = Dyadic(0) + other = _check_dyadic(other) + if (self.args == []) and (other.args == []): + return True + elif (self.args == []) or (other.args == []): + return False + return set(self.args) == set(other.args) + + def __ne__(self, other): + return not self == other + + def __neg__(self): + return self * -1 + + def _latex(self, printer): + ar = self.args # just to shorten things + if len(ar) == 0: + return str(0) + ol = [] # output list, to be concatenated to a string + for i, v in enumerate(ar): + # if the coef of the dyadic is 1, we skip the 1 + if ar[i][0] == 1: + ol.append(' + ' + printer._print(ar[i][1]) + r"\otimes " + + printer._print(ar[i][2])) + # if the coef of the dyadic is -1, we skip the 1 + elif ar[i][0] == -1: + ol.append(' - ' + + printer._print(ar[i][1]) + + r"\otimes " + + printer._print(ar[i][2])) + # If the coefficient of the dyadic is not 1 or -1, + # we might wrap it in parentheses, for readability. + elif ar[i][0] != 0: + arg_str = printer._print(ar[i][0]) + if isinstance(ar[i][0], Add): + arg_str = '(%s)' % arg_str + if arg_str.startswith('-'): + arg_str = arg_str[1:] + str_start = ' - ' + else: + str_start = ' + ' + ol.append(str_start + arg_str + printer._print(ar[i][1]) + + r"\otimes " + printer._print(ar[i][2])) + outstr = ''.join(ol) + if outstr.startswith(' + '): + outstr = outstr[3:] + elif outstr.startswith(' '): + outstr = outstr[1:] + return outstr + + def _pretty(self, printer): + e = self + + class Fake: + baseline = 0 + + def render(self, *args, **kwargs): + ar = e.args # just to shorten things + mpp = printer + if len(ar) == 0: + return str(0) + bar = "\N{CIRCLED TIMES}" if printer._use_unicode else "|" + ol = [] # output list, to be concatenated to a string + for i, v in enumerate(ar): + # if the coef of the dyadic is 1, we skip the 1 + if ar[i][0] == 1: + ol.extend([" + ", + mpp.doprint(ar[i][1]), + bar, + mpp.doprint(ar[i][2])]) + + # if the coef of the dyadic is -1, we skip the 1 + elif ar[i][0] == -1: + ol.extend([" - ", + mpp.doprint(ar[i][1]), + bar, + mpp.doprint(ar[i][2])]) + + # If the coefficient of the dyadic is not 1 or -1, + # we might wrap it in parentheses, for readability. + elif ar[i][0] != 0: + if isinstance(ar[i][0], Add): + arg_str = mpp._print( + ar[i][0]).parens()[0] + else: + arg_str = mpp.doprint(ar[i][0]) + if arg_str.startswith("-"): + arg_str = arg_str[1:] + str_start = " - " + else: + str_start = " + " + ol.extend([str_start, arg_str, " ", + mpp.doprint(ar[i][1]), + bar, + mpp.doprint(ar[i][2])]) + + outstr = "".join(ol) + if outstr.startswith(" + "): + outstr = outstr[3:] + elif outstr.startswith(" "): + outstr = outstr[1:] + return outstr + return Fake() + + def __rsub__(self, other): + return (-1 * self) + other + + def _sympystr(self, printer): + """Printing method. """ + ar = self.args # just to shorten things + if len(ar) == 0: + return printer._print(0) + ol = [] # output list, to be concatenated to a string + for i, v in enumerate(ar): + # if the coef of the dyadic is 1, we skip the 1 + if ar[i][0] == 1: + ol.append(' + (' + printer._print(ar[i][1]) + '|' + + printer._print(ar[i][2]) + ')') + # if the coef of the dyadic is -1, we skip the 1 + elif ar[i][0] == -1: + ol.append(' - (' + printer._print(ar[i][1]) + '|' + + printer._print(ar[i][2]) + ')') + # If the coefficient of the dyadic is not 1 or -1, + # we might wrap it in parentheses, for readability. + elif ar[i][0] != 0: + arg_str = printer._print(ar[i][0]) + if isinstance(ar[i][0], Add): + arg_str = "(%s)" % arg_str + if arg_str[0] == '-': + arg_str = arg_str[1:] + str_start = ' - ' + else: + str_start = ' + ' + ol.append(str_start + arg_str + '*(' + + printer._print(ar[i][1]) + + '|' + printer._print(ar[i][2]) + ')') + outstr = ''.join(ol) + if outstr.startswith(' + '): + outstr = outstr[3:] + elif outstr.startswith(' '): + outstr = outstr[1:] + return outstr + + def __sub__(self, other): + """The subtraction operator. """ + return self.__add__(other * -1) + + def cross(self, other): + """Returns the dyadic resulting from the dyadic vector cross product: + Dyadic x Vector. + + Parameters + ========== + other : Vector + Vector to cross with. + + Examples + ======== + >>> from sympy.physics.vector import ReferenceFrame, outer, cross + >>> N = ReferenceFrame('N') + >>> d = outer(N.x, N.x) + >>> cross(d, N.y) + (N.x|N.z) + + """ + from sympy.physics.vector.vector import _check_vector + other = _check_vector(other) + ol = Dyadic(0) + for v in self.args: + ol += v[0] * (v[1].outer((v[2].cross(other)))) + return ol + + # NOTE : supports non-advertised Dyadic ^ Vector notation + __xor__ = cross + + def express(self, frame1, frame2=None): + """Expresses this Dyadic in alternate frame(s) + + The first frame is the list side expression, the second frame is the + right side; if Dyadic is in form A.x|B.y, you can express it in two + different frames. If no second frame is given, the Dyadic is + expressed in only one frame. + + Calls the global express function + + Parameters + ========== + + frame1 : ReferenceFrame + The frame to express the left side of the Dyadic in + frame2 : ReferenceFrame + If provided, the frame to express the right side of the Dyadic in + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, outer, dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> N = ReferenceFrame('N') + >>> q = dynamicsymbols('q') + >>> B = N.orientnew('B', 'Axis', [q, N.z]) + >>> d = outer(N.x, N.x) + >>> d.express(B, N) + cos(q)*(B.x|N.x) - sin(q)*(B.y|N.x) + + """ + from sympy.physics.vector.functions import express + return express(self, frame1, frame2) + + def to_matrix(self, reference_frame, second_reference_frame=None): + """Returns the matrix form of the dyadic with respect to one or two + reference frames. + + Parameters + ---------- + reference_frame : ReferenceFrame + The reference frame that the rows and columns of the matrix + correspond to. If a second reference frame is provided, this + only corresponds to the rows of the matrix. + second_reference_frame : ReferenceFrame, optional, default=None + The reference frame that the columns of the matrix correspond + to. + + Returns + ------- + matrix : ImmutableMatrix, shape(3,3) + The matrix that gives the 2D tensor form. + + Examples + ======== + + >>> from sympy import symbols, trigsimp + >>> from sympy.physics.vector import ReferenceFrame + >>> from sympy.physics.mechanics import inertia + >>> Ixx, Iyy, Izz, Ixy, Iyz, Ixz = symbols('Ixx, Iyy, Izz, Ixy, Iyz, Ixz') + >>> N = ReferenceFrame('N') + >>> inertia_dyadic = inertia(N, Ixx, Iyy, Izz, Ixy, Iyz, Ixz) + >>> inertia_dyadic.to_matrix(N) + Matrix([ + [Ixx, Ixy, Ixz], + [Ixy, Iyy, Iyz], + [Ixz, Iyz, Izz]]) + >>> beta = symbols('beta') + >>> A = N.orientnew('A', 'Axis', (beta, N.x)) + >>> trigsimp(inertia_dyadic.to_matrix(A)) + Matrix([ + [ Ixx, Ixy*cos(beta) + Ixz*sin(beta), -Ixy*sin(beta) + Ixz*cos(beta)], + [ Ixy*cos(beta) + Ixz*sin(beta), Iyy*cos(2*beta)/2 + Iyy/2 + Iyz*sin(2*beta) - Izz*cos(2*beta)/2 + Izz/2, -Iyy*sin(2*beta)/2 + Iyz*cos(2*beta) + Izz*sin(2*beta)/2], + [-Ixy*sin(beta) + Ixz*cos(beta), -Iyy*sin(2*beta)/2 + Iyz*cos(2*beta) + Izz*sin(2*beta)/2, -Iyy*cos(2*beta)/2 + Iyy/2 - Iyz*sin(2*beta) + Izz*cos(2*beta)/2 + Izz/2]]) + + """ + + if second_reference_frame is None: + second_reference_frame = reference_frame + + return Matrix([i.dot(self).dot(j) for i in reference_frame for j in + second_reference_frame]).reshape(3, 3) + + def doit(self, **hints): + """Calls .doit() on each term in the Dyadic""" + return sum([Dyadic([(v[0].doit(**hints), v[1], v[2])]) + for v in self.args], Dyadic(0)) + + def dt(self, frame): + """Take the time derivative of this Dyadic in a frame. + + This function calls the global time_derivative method + + Parameters + ========== + + frame : ReferenceFrame + The frame to take the time derivative in + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, outer, dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> N = ReferenceFrame('N') + >>> q = dynamicsymbols('q') + >>> B = N.orientnew('B', 'Axis', [q, N.z]) + >>> d = outer(N.x, N.x) + >>> d.dt(B) + - q'*(N.y|N.x) - q'*(N.x|N.y) + + """ + from sympy.physics.vector.functions import time_derivative + return time_derivative(self, frame) + + def simplify(self): + """Returns a simplified Dyadic.""" + out = Dyadic(0) + for v in self.args: + out += Dyadic([(v[0].simplify(), v[1], v[2])]) + return out + + def subs(self, *args, **kwargs): + """Substitution on the Dyadic. + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> from sympy import Symbol + >>> N = ReferenceFrame('N') + >>> s = Symbol('s') + >>> a = s*(N.x|N.x) + >>> a.subs({s: 2}) + 2*(N.x|N.x) + + """ + + return sum([Dyadic([(v[0].subs(*args, **kwargs), v[1], v[2])]) + for v in self.args], Dyadic(0)) + + def applyfunc(self, f): + """Apply a function to each component of a Dyadic.""" + if not callable(f): + raise TypeError("`f` must be callable.") + + out = Dyadic(0) + for a, b, c in self.args: + out += f(a) * (b.outer(c)) + return out + + def _eval_evalf(self, prec): + if not self.args: + return self + new_args = [] + dps = prec_to_dps(prec) + for inlist in self.args: + new_inlist = list(inlist) + new_inlist[0] = inlist[0].evalf(n=dps) + new_args.append(tuple(new_inlist)) + return Dyadic(new_args) + + def xreplace(self, rule): + """ + Replace occurrences of objects within the measure numbers of the + Dyadic. + + Parameters + ========== + + rule : dict-like + Expresses a replacement rule. + + Returns + ======= + + Dyadic + Result of the replacement. + + Examples + ======== + + >>> from sympy import symbols, pi + >>> from sympy.physics.vector import ReferenceFrame, outer + >>> N = ReferenceFrame('N') + >>> D = outer(N.x, N.x) + >>> x, y, z = symbols('x y z') + >>> ((1 + x*y) * D).xreplace({x: pi}) + (pi*y + 1)*(N.x|N.x) + >>> ((1 + x*y) * D).xreplace({x: pi, y: 2}) + (1 + 2*pi)*(N.x|N.x) + + Replacements occur only if an entire node in the expression tree is + matched: + + >>> ((x*y + z) * D).xreplace({x*y: pi}) + (z + pi)*(N.x|N.x) + >>> ((x*y*z) * D).xreplace({x*y: pi}) + x*y*z*(N.x|N.x) + + """ + + new_args = [] + for inlist in self.args: + new_inlist = list(inlist) + new_inlist[0] = new_inlist[0].xreplace(rule) + new_args.append(tuple(new_inlist)) + return Dyadic(new_args) + + +def _check_dyadic(other): + if not isinstance(other, Dyadic): + raise TypeError('A Dyadic must be supplied') + return other diff --git a/lib/python3.12/site-packages/sympy/physics/vector/fieldfunctions.py b/lib/python3.12/site-packages/sympy/physics/vector/fieldfunctions.py new file mode 100644 index 0000000000000000000000000000000000000000..74169921c587385323b9080709999c65c6ca0843 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/fieldfunctions.py @@ -0,0 +1,313 @@ +from sympy.core.function import diff +from sympy.core.singleton import S +from sympy.integrals.integrals import integrate +from sympy.physics.vector import Vector, express +from sympy.physics.vector.frame import _check_frame +from sympy.physics.vector.vector import _check_vector + + +__all__ = ['curl', 'divergence', 'gradient', 'is_conservative', + 'is_solenoidal', 'scalar_potential', + 'scalar_potential_difference'] + + +def curl(vect, frame): + """ + Returns the curl of a vector field computed wrt the coordinate + symbols of the given frame. + + Parameters + ========== + + vect : Vector + The vector operand + + frame : ReferenceFrame + The reference frame to calculate the curl in + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> from sympy.physics.vector import curl + >>> R = ReferenceFrame('R') + >>> v1 = R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z + >>> curl(v1, R) + 0 + >>> v2 = R[0]*R[1]*R[2]*R.x + >>> curl(v2, R) + R_x*R_y*R.y - R_x*R_z*R.z + + """ + + _check_vector(vect) + if vect == 0: + return Vector(0) + vect = express(vect, frame, variables=True) + # A mechanical approach to avoid looping overheads + vectx = vect.dot(frame.x) + vecty = vect.dot(frame.y) + vectz = vect.dot(frame.z) + outvec = Vector(0) + outvec += (diff(vectz, frame[1]) - diff(vecty, frame[2])) * frame.x + outvec += (diff(vectx, frame[2]) - diff(vectz, frame[0])) * frame.y + outvec += (diff(vecty, frame[0]) - diff(vectx, frame[1])) * frame.z + return outvec + + +def divergence(vect, frame): + """ + Returns the divergence of a vector field computed wrt the coordinate + symbols of the given frame. + + Parameters + ========== + + vect : Vector + The vector operand + + frame : ReferenceFrame + The reference frame to calculate the divergence in + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> from sympy.physics.vector import divergence + >>> R = ReferenceFrame('R') + >>> v1 = R[0]*R[1]*R[2] * (R.x+R.y+R.z) + >>> divergence(v1, R) + R_x*R_y + R_x*R_z + R_y*R_z + >>> v2 = 2*R[1]*R[2]*R.y + >>> divergence(v2, R) + 2*R_z + + """ + + _check_vector(vect) + if vect == 0: + return S.Zero + vect = express(vect, frame, variables=True) + vectx = vect.dot(frame.x) + vecty = vect.dot(frame.y) + vectz = vect.dot(frame.z) + out = S.Zero + out += diff(vectx, frame[0]) + out += diff(vecty, frame[1]) + out += diff(vectz, frame[2]) + return out + + +def gradient(scalar, frame): + """ + Returns the vector gradient of a scalar field computed wrt the + coordinate symbols of the given frame. + + Parameters + ========== + + scalar : sympifiable + The scalar field to take the gradient of + + frame : ReferenceFrame + The frame to calculate the gradient in + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> from sympy.physics.vector import gradient + >>> R = ReferenceFrame('R') + >>> s1 = R[0]*R[1]*R[2] + >>> gradient(s1, R) + R_y*R_z*R.x + R_x*R_z*R.y + R_x*R_y*R.z + >>> s2 = 5*R[0]**2*R[2] + >>> gradient(s2, R) + 10*R_x*R_z*R.x + 5*R_x**2*R.z + + """ + + _check_frame(frame) + outvec = Vector(0) + scalar = express(scalar, frame, variables=True) + for i, x in enumerate(frame): + outvec += diff(scalar, frame[i]) * x + return outvec + + +def is_conservative(field): + """ + Checks if a field is conservative. + + Parameters + ========== + + field : Vector + The field to check for conservative property + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> from sympy.physics.vector import is_conservative + >>> R = ReferenceFrame('R') + >>> is_conservative(R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z) + True + >>> is_conservative(R[2] * R.y) + False + + """ + + # Field is conservative irrespective of frame + # Take the first frame in the result of the separate method of Vector + if field == Vector(0): + return True + frame = list(field.separate())[0] + return curl(field, frame).simplify() == Vector(0) + + +def is_solenoidal(field): + """ + Checks if a field is solenoidal. + + Parameters + ========== + + field : Vector + The field to check for solenoidal property + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> from sympy.physics.vector import is_solenoidal + >>> R = ReferenceFrame('R') + >>> is_solenoidal(R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z) + True + >>> is_solenoidal(R[1] * R.y) + False + + """ + + # Field is solenoidal irrespective of frame + # Take the first frame in the result of the separate method in Vector + if field == Vector(0): + return True + frame = list(field.separate())[0] + return divergence(field, frame).simplify() is S.Zero + + +def scalar_potential(field, frame): + """ + Returns the scalar potential function of a field in a given frame + (without the added integration constant). + + Parameters + ========== + + field : Vector + The vector field whose scalar potential function is to be + calculated + + frame : ReferenceFrame + The frame to do the calculation in + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> from sympy.physics.vector import scalar_potential, gradient + >>> R = ReferenceFrame('R') + >>> scalar_potential(R.z, R) == R[2] + True + >>> scalar_field = 2*R[0]**2*R[1]*R[2] + >>> grad_field = gradient(scalar_field, R) + >>> scalar_potential(grad_field, R) + 2*R_x**2*R_y*R_z + + """ + + # Check whether field is conservative + if not is_conservative(field): + raise ValueError("Field is not conservative") + if field == Vector(0): + return S.Zero + # Express the field exntirely in frame + # Substitute coordinate variables also + _check_frame(frame) + field = express(field, frame, variables=True) + # Make a list of dimensions of the frame + dimensions = list(frame) + # Calculate scalar potential function + temp_function = integrate(field.dot(dimensions[0]), frame[0]) + for i, dim in enumerate(dimensions[1:]): + partial_diff = diff(temp_function, frame[i + 1]) + partial_diff = field.dot(dim) - partial_diff + temp_function += integrate(partial_diff, frame[i + 1]) + return temp_function + + +def scalar_potential_difference(field, frame, point1, point2, origin): + """ + Returns the scalar potential difference between two points in a + certain frame, wrt a given field. + + If a scalar field is provided, its values at the two points are + considered. If a conservative vector field is provided, the values + of its scalar potential function at the two points are used. + + Returns (potential at position 2) - (potential at position 1) + + Parameters + ========== + + field : Vector/sympyfiable + The field to calculate wrt + + frame : ReferenceFrame + The frame to do the calculations in + + point1 : Point + The initial Point in given frame + + position2 : Point + The second Point in the given frame + + origin : Point + The Point to use as reference point for position vector + calculation + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, Point + >>> from sympy.physics.vector import scalar_potential_difference + >>> R = ReferenceFrame('R') + >>> O = Point('O') + >>> P = O.locatenew('P', R[0]*R.x + R[1]*R.y + R[2]*R.z) + >>> vectfield = 4*R[0]*R[1]*R.x + 2*R[0]**2*R.y + >>> scalar_potential_difference(vectfield, R, O, P, O) + 2*R_x**2*R_y + >>> Q = O.locatenew('O', 3*R.x + R.y + 2*R.z) + >>> scalar_potential_difference(vectfield, R, P, Q, O) + -2*R_x**2*R_y + 18 + + """ + + _check_frame(frame) + if isinstance(field, Vector): + # Get the scalar potential function + scalar_fn = scalar_potential(field, frame) + else: + # Field is a scalar + scalar_fn = field + # Express positions in required frame + position1 = express(point1.pos_from(origin), frame, variables=True) + position2 = express(point2.pos_from(origin), frame, variables=True) + # Get the two positions as substitution dicts for coordinate variables + subs_dict1 = {} + subs_dict2 = {} + for i, x in enumerate(frame): + subs_dict1[frame[i]] = x.dot(position1) + subs_dict2[frame[i]] = x.dot(position2) + return scalar_fn.subs(subs_dict2) - scalar_fn.subs(subs_dict1) diff --git a/lib/python3.12/site-packages/sympy/physics/vector/frame.py b/lib/python3.12/site-packages/sympy/physics/vector/frame.py new file mode 100644 index 0000000000000000000000000000000000000000..dd0945fbf38d67b020dd88b67ae23984fa263ce1 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/frame.py @@ -0,0 +1,1575 @@ +from sympy import (diff, expand, sin, cos, sympify, eye, zeros, + ImmutableMatrix as Matrix, MatrixBase) +from sympy.core.symbol import Symbol +from sympy.simplify.trigsimp import trigsimp +from sympy.physics.vector.vector import Vector, _check_vector +from sympy.utilities.misc import translate + +from warnings import warn + +__all__ = ['CoordinateSym', 'ReferenceFrame'] + + +class CoordinateSym(Symbol): + """ + A coordinate symbol/base scalar associated wrt a Reference Frame. + + Ideally, users should not instantiate this class. Instances of + this class must only be accessed through the corresponding frame + as 'frame[index]'. + + CoordinateSyms having the same frame and index parameters are equal + (even though they may be instantiated separately). + + Parameters + ========== + + name : string + The display name of the CoordinateSym + + frame : ReferenceFrame + The reference frame this base scalar belongs to + + index : 0, 1 or 2 + The index of the dimension denoted by this coordinate variable + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, CoordinateSym + >>> A = ReferenceFrame('A') + >>> A[1] + A_y + >>> type(A[0]) + + >>> a_y = CoordinateSym('a_y', A, 1) + >>> a_y == A[1] + True + + """ + + def __new__(cls, name, frame, index): + # We can't use the cached Symbol.__new__ because this class depends on + # frame and index, which are not passed to Symbol.__xnew__. + assumptions = {} + super()._sanitize(assumptions, cls) + obj = super().__xnew__(cls, name, **assumptions) + _check_frame(frame) + if index not in range(0, 3): + raise ValueError("Invalid index specified") + obj._id = (frame, index) + return obj + + def __getnewargs_ex__(self): + return (self.name, *self._id), {} + + @property + def frame(self): + return self._id[0] + + def __eq__(self, other): + # Check if the other object is a CoordinateSym of the same frame and + # same index + if isinstance(other, CoordinateSym): + if other._id == self._id: + return True + return False + + def __ne__(self, other): + return not self == other + + def __hash__(self): + return (self._id[0].__hash__(), self._id[1]).__hash__() + + +class ReferenceFrame: + """A reference frame in classical mechanics. + + ReferenceFrame is a class used to represent a reference frame in classical + mechanics. It has a standard basis of three unit vectors in the frame's + x, y, and z directions. + + It also can have a rotation relative to a parent frame; this rotation is + defined by a direction cosine matrix relating this frame's basis vectors to + the parent frame's basis vectors. It can also have an angular velocity + vector, defined in another frame. + + """ + _count = 0 + + def __init__(self, name, indices=None, latexs=None, variables=None): + """ReferenceFrame initialization method. + + A ReferenceFrame has a set of orthonormal basis vectors, along with + orientations relative to other ReferenceFrames and angular velocities + relative to other ReferenceFrames. + + Parameters + ========== + + indices : tuple of str + Enables the reference frame's basis unit vectors to be accessed by + Python's square bracket indexing notation using the provided three + indice strings and alters the printing of the unit vectors to + reflect this choice. + latexs : tuple of str + Alters the LaTeX printing of the reference frame's basis unit + vectors to the provided three valid LaTeX strings. + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, vlatex + >>> N = ReferenceFrame('N') + >>> N.x + N.x + >>> O = ReferenceFrame('O', indices=('1', '2', '3')) + >>> O.x + O['1'] + >>> O['1'] + O['1'] + >>> P = ReferenceFrame('P', latexs=('A1', 'A2', 'A3')) + >>> vlatex(P.x) + 'A1' + + ``symbols()`` can be used to create multiple Reference Frames in one + step, for example: + + >>> from sympy.physics.vector import ReferenceFrame + >>> from sympy import symbols + >>> A, B, C = symbols('A B C', cls=ReferenceFrame) + >>> D, E = symbols('D E', cls=ReferenceFrame, indices=('1', '2', '3')) + >>> A[0] + A_x + >>> D.x + D['1'] + >>> E.y + E['2'] + >>> type(A) == type(D) + True + + Unit dyads for the ReferenceFrame can be accessed through the attributes ``xx``, ``xy``, etc. For example: + + >>> from sympy.physics.vector import ReferenceFrame + >>> N = ReferenceFrame('N') + >>> N.yz + (N.y|N.z) + >>> N.zx + (N.z|N.x) + >>> P = ReferenceFrame('P', indices=['1', '2', '3']) + >>> P.xx + (P['1']|P['1']) + >>> P.zy + (P['3']|P['2']) + + Unit dyadic is also accessible via the ``u`` attribute: + + >>> from sympy.physics.vector import ReferenceFrame + >>> N = ReferenceFrame('N') + >>> N.u + (N.x|N.x) + (N.y|N.y) + (N.z|N.z) + >>> P = ReferenceFrame('P', indices=['1', '2', '3']) + >>> P.u + (P['1']|P['1']) + (P['2']|P['2']) + (P['3']|P['3']) + + """ + + if not isinstance(name, str): + raise TypeError('Need to supply a valid name') + # The if statements below are for custom printing of basis-vectors for + # each frame. + # First case, when custom indices are supplied + if indices is not None: + if not isinstance(indices, (tuple, list)): + raise TypeError('Supply the indices as a list') + if len(indices) != 3: + raise ValueError('Supply 3 indices') + for i in indices: + if not isinstance(i, str): + raise TypeError('Indices must be strings') + self.str_vecs = [(name + '[\'' + indices[0] + '\']'), + (name + '[\'' + indices[1] + '\']'), + (name + '[\'' + indices[2] + '\']')] + self.pretty_vecs = [(name.lower() + "_" + indices[0]), + (name.lower() + "_" + indices[1]), + (name.lower() + "_" + indices[2])] + self.latex_vecs = [(r"\mathbf{\hat{%s}_{%s}}" % (name.lower(), + indices[0])), + (r"\mathbf{\hat{%s}_{%s}}" % (name.lower(), + indices[1])), + (r"\mathbf{\hat{%s}_{%s}}" % (name.lower(), + indices[2]))] + self.indices = indices + # Second case, when no custom indices are supplied + else: + self.str_vecs = [(name + '.x'), (name + '.y'), (name + '.z')] + self.pretty_vecs = [name.lower() + "_x", + name.lower() + "_y", + name.lower() + "_z"] + self.latex_vecs = [(r"\mathbf{\hat{%s}_x}" % name.lower()), + (r"\mathbf{\hat{%s}_y}" % name.lower()), + (r"\mathbf{\hat{%s}_z}" % name.lower())] + self.indices = ['x', 'y', 'z'] + # Different step, for custom latex basis vectors + if latexs is not None: + if not isinstance(latexs, (tuple, list)): + raise TypeError('Supply the indices as a list') + if len(latexs) != 3: + raise ValueError('Supply 3 indices') + for i in latexs: + if not isinstance(i, str): + raise TypeError('Latex entries must be strings') + self.latex_vecs = latexs + self.name = name + self._var_dict = {} + # The _dcm_dict dictionary will only store the dcms of adjacent + # parent-child relationships. The _dcm_cache dictionary will store + # calculated dcm along with all content of _dcm_dict for faster + # retrieval of dcms. + self._dcm_dict = {} + self._dcm_cache = {} + self._ang_vel_dict = {} + self._ang_acc_dict = {} + self._dlist = [self._dcm_dict, self._ang_vel_dict, self._ang_acc_dict] + self._cur = 0 + self._x = Vector([(Matrix([1, 0, 0]), self)]) + self._y = Vector([(Matrix([0, 1, 0]), self)]) + self._z = Vector([(Matrix([0, 0, 1]), self)]) + # Associate coordinate symbols wrt this frame + if variables is not None: + if not isinstance(variables, (tuple, list)): + raise TypeError('Supply the variable names as a list/tuple') + if len(variables) != 3: + raise ValueError('Supply 3 variable names') + for i in variables: + if not isinstance(i, str): + raise TypeError('Variable names must be strings') + else: + variables = [name + '_x', name + '_y', name + '_z'] + self.varlist = (CoordinateSym(variables[0], self, 0), + CoordinateSym(variables[1], self, 1), + CoordinateSym(variables[2], self, 2)) + ReferenceFrame._count += 1 + self.index = ReferenceFrame._count + + def __getitem__(self, ind): + """ + Returns basis vector for the provided index, if the index is a string. + + If the index is a number, returns the coordinate variable correspon- + -ding to that index. + """ + if not isinstance(ind, str): + if ind < 3: + return self.varlist[ind] + else: + raise ValueError("Invalid index provided") + if self.indices[0] == ind: + return self.x + if self.indices[1] == ind: + return self.y + if self.indices[2] == ind: + return self.z + else: + raise ValueError('Not a defined index') + + def __iter__(self): + return iter([self.x, self.y, self.z]) + + def __str__(self): + """Returns the name of the frame. """ + return self.name + + __repr__ = __str__ + + def _dict_list(self, other, num): + """Returns an inclusive list of reference frames that connect this + reference frame to the provided reference frame. + + Parameters + ========== + other : ReferenceFrame + The other reference frame to look for a connecting relationship to. + num : integer + ``0``, ``1``, and ``2`` will look for orientation, angular + velocity, and angular acceleration relationships between the two + frames, respectively. + + Returns + ======= + list + Inclusive list of reference frames that connect this reference + frame to the other reference frame. + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> A = ReferenceFrame('A') + >>> B = ReferenceFrame('B') + >>> C = ReferenceFrame('C') + >>> D = ReferenceFrame('D') + >>> B.orient_axis(A, A.x, 1.0) + >>> C.orient_axis(B, B.x, 1.0) + >>> D.orient_axis(C, C.x, 1.0) + >>> D._dict_list(A, 0) + [D, C, B, A] + + Raises + ====== + + ValueError + When no path is found between the two reference frames or ``num`` + is an incorrect value. + + """ + + connect_type = {0: 'orientation', + 1: 'angular velocity', + 2: 'angular acceleration'} + + if num not in connect_type.keys(): + raise ValueError('Valid values for num are 0, 1, or 2.') + + possible_connecting_paths = [[self]] + oldlist = [[]] + while possible_connecting_paths != oldlist: + oldlist = possible_connecting_paths[:] # make a copy + for frame_list in possible_connecting_paths: + frames_adjacent_to_last = frame_list[-1]._dlist[num].keys() + for adjacent_frame in frames_adjacent_to_last: + if adjacent_frame not in frame_list: + connecting_path = frame_list + [adjacent_frame] + if connecting_path not in possible_connecting_paths: + possible_connecting_paths.append(connecting_path) + + for connecting_path in oldlist: + if connecting_path[-1] != other: + possible_connecting_paths.remove(connecting_path) + possible_connecting_paths.sort(key=len) + + if len(possible_connecting_paths) != 0: + return possible_connecting_paths[0] # selects the shortest path + + msg = 'No connecting {} path found between {} and {}.' + raise ValueError(msg.format(connect_type[num], self.name, other.name)) + + def _w_diff_dcm(self, otherframe): + """Angular velocity from time differentiating the DCM. """ + from sympy.physics.vector.functions import dynamicsymbols + dcm2diff = otherframe.dcm(self) + diffed = dcm2diff.diff(dynamicsymbols._t) + angvelmat = diffed * dcm2diff.T + w1 = trigsimp(expand(angvelmat[7]), recursive=True) + w2 = trigsimp(expand(angvelmat[2]), recursive=True) + w3 = trigsimp(expand(angvelmat[3]), recursive=True) + return Vector([(Matrix([w1, w2, w3]), otherframe)]) + + def variable_map(self, otherframe): + """ + Returns a dictionary which expresses the coordinate variables + of this frame in terms of the variables of otherframe. + + If Vector.simp is True, returns a simplified version of the mapped + values. Else, returns them without simplification. + + Simplification of the expressions may take time. + + Parameters + ========== + + otherframe : ReferenceFrame + The other frame to map the variables to + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, dynamicsymbols + >>> A = ReferenceFrame('A') + >>> q = dynamicsymbols('q') + >>> B = A.orientnew('B', 'Axis', [q, A.z]) + >>> A.variable_map(B) + {A_x: B_x*cos(q(t)) - B_y*sin(q(t)), A_y: B_x*sin(q(t)) + B_y*cos(q(t)), A_z: B_z} + + """ + + _check_frame(otherframe) + if (otherframe, Vector.simp) in self._var_dict: + return self._var_dict[(otherframe, Vector.simp)] + else: + vars_matrix = self.dcm(otherframe) * Matrix(otherframe.varlist) + mapping = {} + for i, x in enumerate(self): + if Vector.simp: + mapping[self.varlist[i]] = trigsimp(vars_matrix[i], + method='fu') + else: + mapping[self.varlist[i]] = vars_matrix[i] + self._var_dict[(otherframe, Vector.simp)] = mapping + return mapping + + def ang_acc_in(self, otherframe): + """Returns the angular acceleration Vector of the ReferenceFrame. + + Effectively returns the Vector: + + ``N_alpha_B`` + + which represent the angular acceleration of B in N, where B is self, + and N is otherframe. + + Parameters + ========== + + otherframe : ReferenceFrame + The ReferenceFrame which the angular acceleration is returned in. + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> N = ReferenceFrame('N') + >>> A = ReferenceFrame('A') + >>> V = 10 * N.x + >>> A.set_ang_acc(N, V) + >>> A.ang_acc_in(N) + 10*N.x + + """ + + _check_frame(otherframe) + if otherframe in self._ang_acc_dict: + return self._ang_acc_dict[otherframe] + else: + return self.ang_vel_in(otherframe).dt(otherframe) + + def ang_vel_in(self, otherframe): + """Returns the angular velocity Vector of the ReferenceFrame. + + Effectively returns the Vector: + + ^N omega ^B + + which represent the angular velocity of B in N, where B is self, and + N is otherframe. + + Parameters + ========== + + otherframe : ReferenceFrame + The ReferenceFrame which the angular velocity is returned in. + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> N = ReferenceFrame('N') + >>> A = ReferenceFrame('A') + >>> V = 10 * N.x + >>> A.set_ang_vel(N, V) + >>> A.ang_vel_in(N) + 10*N.x + + """ + + _check_frame(otherframe) + flist = self._dict_list(otherframe, 1) + outvec = Vector(0) + for i in range(len(flist) - 1): + outvec += flist[i]._ang_vel_dict[flist[i + 1]] + return outvec + + def dcm(self, otherframe): + r"""Returns the direction cosine matrix of this reference frame + relative to the provided reference frame. + + The returned matrix can be used to express the orthogonal unit vectors + of this frame in terms of the orthogonal unit vectors of + ``otherframe``. + + Parameters + ========== + + otherframe : ReferenceFrame + The reference frame which the direction cosine matrix of this frame + is formed relative to. + + Examples + ======== + + The following example rotates the reference frame A relative to N by a + simple rotation and then calculates the direction cosine matrix of N + relative to A. + + >>> from sympy import symbols, sin, cos + >>> from sympy.physics.vector import ReferenceFrame + >>> q1 = symbols('q1') + >>> N = ReferenceFrame('N') + >>> A = ReferenceFrame('A') + >>> A.orient_axis(N, q1, N.x) + >>> N.dcm(A) + Matrix([ + [1, 0, 0], + [0, cos(q1), -sin(q1)], + [0, sin(q1), cos(q1)]]) + + The second row of the above direction cosine matrix represents the + ``N.y`` unit vector in N expressed in A. Like so: + + >>> Ny = 0*A.x + cos(q1)*A.y - sin(q1)*A.z + + Thus, expressing ``N.y`` in A should return the same result: + + >>> N.y.express(A) + cos(q1)*A.y - sin(q1)*A.z + + Notes + ===== + + It is important to know what form of the direction cosine matrix is + returned. If ``B.dcm(A)`` is called, it means the "direction cosine + matrix of B rotated relative to A". This is the matrix + :math:`{}^B\mathbf{C}^A` shown in the following relationship: + + .. math:: + + \begin{bmatrix} + \hat{\mathbf{b}}_1 \\ + \hat{\mathbf{b}}_2 \\ + \hat{\mathbf{b}}_3 + \end{bmatrix} + = + {}^B\mathbf{C}^A + \begin{bmatrix} + \hat{\mathbf{a}}_1 \\ + \hat{\mathbf{a}}_2 \\ + \hat{\mathbf{a}}_3 + \end{bmatrix}. + + :math:`{}^B\mathbf{C}^A` is the matrix that expresses the B unit + vectors in terms of the A unit vectors. + + """ + + _check_frame(otherframe) + # Check if the dcm wrt that frame has already been calculated + if otherframe in self._dcm_cache: + return self._dcm_cache[otherframe] + flist = self._dict_list(otherframe, 0) + outdcm = eye(3) + for i in range(len(flist) - 1): + outdcm = outdcm * flist[i]._dcm_dict[flist[i + 1]] + # After calculation, store the dcm in dcm cache for faster future + # retrieval + self._dcm_cache[otherframe] = outdcm + otherframe._dcm_cache[self] = outdcm.T + return outdcm + + def _dcm(self, parent, parent_orient): + # If parent.oreint(self) is already defined,then + # update the _dcm_dict of parent while over write + # all content of self._dcm_dict and self._dcm_cache + # with new dcm relation. + # Else update _dcm_cache and _dcm_dict of both + # self and parent. + frames = self._dcm_cache.keys() + dcm_dict_del = [] + dcm_cache_del = [] + if parent in frames: + for frame in frames: + if frame in self._dcm_dict: + dcm_dict_del += [frame] + dcm_cache_del += [frame] + # Reset the _dcm_cache of this frame, and remove it from the + # _dcm_caches of the frames it is linked to. Also remove it from + # the _dcm_dict of its parent + for frame in dcm_dict_del: + del frame._dcm_dict[self] + for frame in dcm_cache_del: + del frame._dcm_cache[self] + # Reset the _dcm_dict + self._dcm_dict = self._dlist[0] = {} + # Reset the _dcm_cache + self._dcm_cache = {} + + else: + # Check for loops and raise warning accordingly. + visited = [] + queue = list(frames) + cont = True # Flag to control queue loop. + while queue and cont: + node = queue.pop(0) + if node not in visited: + visited.append(node) + neighbors = node._dcm_dict.keys() + for neighbor in neighbors: + if neighbor == parent: + warn('Loops are defined among the orientation of ' + 'frames. This is likely not desired and may ' + 'cause errors in your calculations.') + cont = False + break + queue.append(neighbor) + + # Add the dcm relationship to _dcm_dict + self._dcm_dict.update({parent: parent_orient.T}) + parent._dcm_dict.update({self: parent_orient}) + # Update the dcm cache + self._dcm_cache.update({parent: parent_orient.T}) + parent._dcm_cache.update({self: parent_orient}) + + def orient_axis(self, parent, axis, angle): + """Sets the orientation of this reference frame with respect to a + parent reference frame by rotating through an angle about an axis fixed + in the parent reference frame. + + Parameters + ========== + + parent : ReferenceFrame + Reference frame that this reference frame will be rotated relative + to. + axis : Vector + Vector fixed in the parent frame about about which this frame is + rotated. It need not be a unit vector and the rotation follows the + right hand rule. + angle : sympifiable + Angle in radians by which it the frame is to be rotated. + + Warns + ====== + + UserWarning + If the orientation creates a kinematic loop. + + Examples + ======== + + Setup variables for the examples: + + >>> from sympy import symbols + >>> from sympy.physics.vector import ReferenceFrame + >>> q1 = symbols('q1') + >>> N = ReferenceFrame('N') + >>> B = ReferenceFrame('B') + >>> B.orient_axis(N, N.x, q1) + + The ``orient_axis()`` method generates a direction cosine matrix and + its transpose which defines the orientation of B relative to N and vice + versa. Once orient is called, ``dcm()`` outputs the appropriate + direction cosine matrix: + + >>> B.dcm(N) + Matrix([ + [1, 0, 0], + [0, cos(q1), sin(q1)], + [0, -sin(q1), cos(q1)]]) + >>> N.dcm(B) + Matrix([ + [1, 0, 0], + [0, cos(q1), -sin(q1)], + [0, sin(q1), cos(q1)]]) + + The following two lines show that the sense of the rotation can be + defined by negating the vector direction or the angle. Both lines + produce the same result. + + >>> B.orient_axis(N, -N.x, q1) + >>> B.orient_axis(N, N.x, -q1) + + """ + + from sympy.physics.vector.functions import dynamicsymbols + _check_frame(parent) + + if not isinstance(axis, Vector) and isinstance(angle, Vector): + axis, angle = angle, axis + + axis = _check_vector(axis) + theta = sympify(angle) + + if not axis.dt(parent) == 0: + raise ValueError('Axis cannot be time-varying.') + unit_axis = axis.express(parent).normalize() + unit_col = unit_axis.args[0][0] + parent_orient_axis = ( + (eye(3) - unit_col * unit_col.T) * cos(theta) + + Matrix([[0, -unit_col[2], unit_col[1]], + [unit_col[2], 0, -unit_col[0]], + [-unit_col[1], unit_col[0], 0]]) * + sin(theta) + unit_col * unit_col.T) + + self._dcm(parent, parent_orient_axis) + + thetad = (theta).diff(dynamicsymbols._t) + wvec = thetad*axis.express(parent).normalize() + self._ang_vel_dict.update({parent: wvec}) + parent._ang_vel_dict.update({self: -wvec}) + self._var_dict = {} + + def orient_explicit(self, parent, dcm): + """Sets the orientation of this reference frame relative to another (parent) reference frame + using a direction cosine matrix that describes the rotation from the parent to the child. + + Parameters + ========== + + parent : ReferenceFrame + Reference frame that this reference frame will be rotated relative + to. + dcm : Matrix, shape(3, 3) + Direction cosine matrix that specifies the relative rotation + between the two reference frames. + + Warns + ====== + + UserWarning + If the orientation creates a kinematic loop. + + Examples + ======== + + Setup variables for the examples: + + >>> from sympy import symbols, Matrix, sin, cos + >>> from sympy.physics.vector import ReferenceFrame + >>> q1 = symbols('q1') + >>> A = ReferenceFrame('A') + >>> B = ReferenceFrame('B') + >>> N = ReferenceFrame('N') + + A simple rotation of ``A`` relative to ``N`` about ``N.x`` is defined + by the following direction cosine matrix: + + >>> dcm = Matrix([[1, 0, 0], + ... [0, cos(q1), -sin(q1)], + ... [0, sin(q1), cos(q1)]]) + >>> A.orient_explicit(N, dcm) + >>> A.dcm(N) + Matrix([ + [1, 0, 0], + [0, cos(q1), sin(q1)], + [0, -sin(q1), cos(q1)]]) + + This is equivalent to using ``orient_axis()``: + + >>> B.orient_axis(N, N.x, q1) + >>> B.dcm(N) + Matrix([ + [1, 0, 0], + [0, cos(q1), sin(q1)], + [0, -sin(q1), cos(q1)]]) + + **Note carefully that** ``N.dcm(B)`` **(the transpose) would be passed + into** ``orient_explicit()`` **for** ``A.dcm(N)`` **to match** + ``B.dcm(N)``: + + >>> A.orient_explicit(N, N.dcm(B)) + >>> A.dcm(N) + Matrix([ + [1, 0, 0], + [0, cos(q1), sin(q1)], + [0, -sin(q1), cos(q1)]]) + + """ + _check_frame(parent) + # amounts must be a Matrix type object + # (e.g. sympy.matrices.dense.MutableDenseMatrix). + if not isinstance(dcm, MatrixBase): + raise TypeError("Amounts must be a SymPy Matrix type object.") + + self.orient_dcm(parent, dcm.T) + + def orient_dcm(self, parent, dcm): + """Sets the orientation of this reference frame relative to another (parent) reference frame + using a direction cosine matrix that describes the rotation from the child to the parent. + + Parameters + ========== + + parent : ReferenceFrame + Reference frame that this reference frame will be rotated relative + to. + dcm : Matrix, shape(3, 3) + Direction cosine matrix that specifies the relative rotation + between the two reference frames. + + Warns + ====== + + UserWarning + If the orientation creates a kinematic loop. + + Examples + ======== + + Setup variables for the examples: + + >>> from sympy import symbols, Matrix, sin, cos + >>> from sympy.physics.vector import ReferenceFrame + >>> q1 = symbols('q1') + >>> A = ReferenceFrame('A') + >>> B = ReferenceFrame('B') + >>> N = ReferenceFrame('N') + + A simple rotation of ``A`` relative to ``N`` about ``N.x`` is defined + by the following direction cosine matrix: + + >>> dcm = Matrix([[1, 0, 0], + ... [0, cos(q1), sin(q1)], + ... [0, -sin(q1), cos(q1)]]) + >>> A.orient_dcm(N, dcm) + >>> A.dcm(N) + Matrix([ + [1, 0, 0], + [0, cos(q1), sin(q1)], + [0, -sin(q1), cos(q1)]]) + + This is equivalent to using ``orient_axis()``: + + >>> B.orient_axis(N, N.x, q1) + >>> B.dcm(N) + Matrix([ + [1, 0, 0], + [0, cos(q1), sin(q1)], + [0, -sin(q1), cos(q1)]]) + + """ + + _check_frame(parent) + # amounts must be a Matrix type object + # (e.g. sympy.matrices.dense.MutableDenseMatrix). + if not isinstance(dcm, MatrixBase): + raise TypeError("Amounts must be a SymPy Matrix type object.") + + self._dcm(parent, dcm.T) + + wvec = self._w_diff_dcm(parent) + self._ang_vel_dict.update({parent: wvec}) + parent._ang_vel_dict.update({self: -wvec}) + self._var_dict = {} + + def _rot(self, axis, angle): + """DCM for simple axis 1,2,or 3 rotations.""" + if axis == 1: + return Matrix([[1, 0, 0], + [0, cos(angle), -sin(angle)], + [0, sin(angle), cos(angle)]]) + elif axis == 2: + return Matrix([[cos(angle), 0, sin(angle)], + [0, 1, 0], + [-sin(angle), 0, cos(angle)]]) + elif axis == 3: + return Matrix([[cos(angle), -sin(angle), 0], + [sin(angle), cos(angle), 0], + [0, 0, 1]]) + + def _parse_consecutive_rotations(self, angles, rotation_order): + """Helper for orient_body_fixed and orient_space_fixed. + + Parameters + ========== + angles : 3-tuple of sympifiable + Three angles in radians used for the successive rotations. + rotation_order : 3 character string or 3 digit integer + Order of the rotations. The order can be specified by the strings + ``'XZX'``, ``'131'``, or the integer ``131``. There are 12 unique + valid rotation orders. + + Returns + ======= + + amounts : list + List of sympifiables corresponding to the rotation angles. + rot_order : list + List of integers corresponding to the axis of rotation. + rot_matrices : list + List of DCM around the given axis with corresponding magnitude. + + """ + amounts = list(angles) + for i, v in enumerate(amounts): + if not isinstance(v, Vector): + amounts[i] = sympify(v) + + approved_orders = ('123', '231', '312', '132', '213', '321', '121', + '131', '212', '232', '313', '323', '') + # make sure XYZ => 123 + rot_order = translate(str(rotation_order), 'XYZxyz', '123123') + if rot_order not in approved_orders: + raise TypeError('The rotation order is not a valid order.') + + rot_order = [int(r) for r in rot_order] + if not (len(amounts) == 3 & len(rot_order) == 3): + raise TypeError('Body orientation takes 3 values & 3 orders') + rot_matrices = [self._rot(order, amount) + for (order, amount) in zip(rot_order, amounts)] + return amounts, rot_order, rot_matrices + + def orient_body_fixed(self, parent, angles, rotation_order): + """Rotates this reference frame relative to the parent reference frame + by right hand rotating through three successive body fixed simple axis + rotations. Each subsequent axis of rotation is about the "body fixed" + unit vectors of a new intermediate reference frame. This type of + rotation is also referred to rotating through the `Euler and Tait-Bryan + Angles`_. + + .. _Euler and Tait-Bryan Angles: https://en.wikipedia.org/wiki/Euler_angles + + The computed angular velocity in this method is by default expressed in + the child's frame, so it is most preferable to use ``u1 * child.x + u2 * + child.y + u3 * child.z`` as generalized speeds. + + Parameters + ========== + + parent : ReferenceFrame + Reference frame that this reference frame will be rotated relative + to. + angles : 3-tuple of sympifiable + Three angles in radians used for the successive rotations. + rotation_order : 3 character string or 3 digit integer + Order of the rotations about each intermediate reference frames' + unit vectors. The Euler rotation about the X, Z', X'' axes can be + specified by the strings ``'XZX'``, ``'131'``, or the integer + ``131``. There are 12 unique valid rotation orders (6 Euler and 6 + Tait-Bryan): zxz, xyx, yzy, zyz, xzx, yxy, xyz, yzx, zxy, xzy, zyx, + and yxz. + + Warns + ====== + + UserWarning + If the orientation creates a kinematic loop. + + Examples + ======== + + Setup variables for the examples: + + >>> from sympy import symbols + >>> from sympy.physics.vector import ReferenceFrame + >>> q1, q2, q3 = symbols('q1, q2, q3') + >>> N = ReferenceFrame('N') + >>> B = ReferenceFrame('B') + >>> B1 = ReferenceFrame('B1') + >>> B2 = ReferenceFrame('B2') + >>> B3 = ReferenceFrame('B3') + + For example, a classic Euler Angle rotation can be done by: + + >>> B.orient_body_fixed(N, (q1, q2, q3), 'XYX') + >>> B.dcm(N) + Matrix([ + [ cos(q2), sin(q1)*sin(q2), -sin(q2)*cos(q1)], + [sin(q2)*sin(q3), -sin(q1)*sin(q3)*cos(q2) + cos(q1)*cos(q3), sin(q1)*cos(q3) + sin(q3)*cos(q1)*cos(q2)], + [sin(q2)*cos(q3), -sin(q1)*cos(q2)*cos(q3) - sin(q3)*cos(q1), -sin(q1)*sin(q3) + cos(q1)*cos(q2)*cos(q3)]]) + + This rotates reference frame B relative to reference frame N through + ``q1`` about ``N.x``, then rotates B again through ``q2`` about + ``B.y``, and finally through ``q3`` about ``B.x``. It is equivalent to + three successive ``orient_axis()`` calls: + + >>> B1.orient_axis(N, N.x, q1) + >>> B2.orient_axis(B1, B1.y, q2) + >>> B3.orient_axis(B2, B2.x, q3) + >>> B3.dcm(N) + Matrix([ + [ cos(q2), sin(q1)*sin(q2), -sin(q2)*cos(q1)], + [sin(q2)*sin(q3), -sin(q1)*sin(q3)*cos(q2) + cos(q1)*cos(q3), sin(q1)*cos(q3) + sin(q3)*cos(q1)*cos(q2)], + [sin(q2)*cos(q3), -sin(q1)*cos(q2)*cos(q3) - sin(q3)*cos(q1), -sin(q1)*sin(q3) + cos(q1)*cos(q2)*cos(q3)]]) + + Acceptable rotation orders are of length 3, expressed in as a string + ``'XYZ'`` or ``'123'`` or integer ``123``. Rotations about an axis + twice in a row are prohibited. + + >>> B.orient_body_fixed(N, (q1, q2, 0), 'ZXZ') + >>> B.orient_body_fixed(N, (q1, q2, 0), '121') + >>> B.orient_body_fixed(N, (q1, q2, q3), 123) + + """ + from sympy.physics.vector.functions import dynamicsymbols + + _check_frame(parent) + + amounts, rot_order, rot_matrices = self._parse_consecutive_rotations( + angles, rotation_order) + self._dcm(parent, rot_matrices[0] * rot_matrices[1] * rot_matrices[2]) + + rot_vecs = [zeros(3, 1) for _ in range(3)] + for i, order in enumerate(rot_order): + rot_vecs[i][order - 1] = amounts[i].diff(dynamicsymbols._t) + u1, u2, u3 = rot_vecs[2] + rot_matrices[2].T * ( + rot_vecs[1] + rot_matrices[1].T * rot_vecs[0]) + wvec = u1 * self.x + u2 * self.y + u3 * self.z # There is a double - + self._ang_vel_dict.update({parent: wvec}) + parent._ang_vel_dict.update({self: -wvec}) + self._var_dict = {} + + def orient_space_fixed(self, parent, angles, rotation_order): + """Rotates this reference frame relative to the parent reference frame + by right hand rotating through three successive space fixed simple axis + rotations. Each subsequent axis of rotation is about the "space fixed" + unit vectors of the parent reference frame. + + The computed angular velocity in this method is by default expressed in + the child's frame, so it is most preferable to use ``u1 * child.x + u2 * + child.y + u3 * child.z`` as generalized speeds. + + Parameters + ========== + parent : ReferenceFrame + Reference frame that this reference frame will be rotated relative + to. + angles : 3-tuple of sympifiable + Three angles in radians used for the successive rotations. + rotation_order : 3 character string or 3 digit integer + Order of the rotations about the parent reference frame's unit + vectors. The order can be specified by the strings ``'XZX'``, + ``'131'``, or the integer ``131``. There are 12 unique valid + rotation orders. + + Warns + ====== + + UserWarning + If the orientation creates a kinematic loop. + + Examples + ======== + + Setup variables for the examples: + + >>> from sympy import symbols + >>> from sympy.physics.vector import ReferenceFrame + >>> q1, q2, q3 = symbols('q1, q2, q3') + >>> N = ReferenceFrame('N') + >>> B = ReferenceFrame('B') + >>> B1 = ReferenceFrame('B1') + >>> B2 = ReferenceFrame('B2') + >>> B3 = ReferenceFrame('B3') + + >>> B.orient_space_fixed(N, (q1, q2, q3), '312') + >>> B.dcm(N) + Matrix([ + [ sin(q1)*sin(q2)*sin(q3) + cos(q1)*cos(q3), sin(q1)*cos(q2), sin(q1)*sin(q2)*cos(q3) - sin(q3)*cos(q1)], + [-sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1), cos(q1)*cos(q2), sin(q1)*sin(q3) + sin(q2)*cos(q1)*cos(q3)], + [ sin(q3)*cos(q2), -sin(q2), cos(q2)*cos(q3)]]) + + is equivalent to: + + >>> B1.orient_axis(N, N.z, q1) + >>> B2.orient_axis(B1, N.x, q2) + >>> B3.orient_axis(B2, N.y, q3) + >>> B3.dcm(N).simplify() + Matrix([ + [ sin(q1)*sin(q2)*sin(q3) + cos(q1)*cos(q3), sin(q1)*cos(q2), sin(q1)*sin(q2)*cos(q3) - sin(q3)*cos(q1)], + [-sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1), cos(q1)*cos(q2), sin(q1)*sin(q3) + sin(q2)*cos(q1)*cos(q3)], + [ sin(q3)*cos(q2), -sin(q2), cos(q2)*cos(q3)]]) + + It is worth noting that space-fixed and body-fixed rotations are + related by the order of the rotations, i.e. the reverse order of body + fixed will give space fixed and vice versa. + + >>> B.orient_space_fixed(N, (q1, q2, q3), '231') + >>> B.dcm(N) + Matrix([ + [cos(q1)*cos(q2), sin(q1)*sin(q3) + sin(q2)*cos(q1)*cos(q3), -sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1)], + [ -sin(q2), cos(q2)*cos(q3), sin(q3)*cos(q2)], + [sin(q1)*cos(q2), sin(q1)*sin(q2)*cos(q3) - sin(q3)*cos(q1), sin(q1)*sin(q2)*sin(q3) + cos(q1)*cos(q3)]]) + + >>> B.orient_body_fixed(N, (q3, q2, q1), '132') + >>> B.dcm(N) + Matrix([ + [cos(q1)*cos(q2), sin(q1)*sin(q3) + sin(q2)*cos(q1)*cos(q3), -sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1)], + [ -sin(q2), cos(q2)*cos(q3), sin(q3)*cos(q2)], + [sin(q1)*cos(q2), sin(q1)*sin(q2)*cos(q3) - sin(q3)*cos(q1), sin(q1)*sin(q2)*sin(q3) + cos(q1)*cos(q3)]]) + + """ + from sympy.physics.vector.functions import dynamicsymbols + + _check_frame(parent) + + amounts, rot_order, rot_matrices = self._parse_consecutive_rotations( + angles, rotation_order) + self._dcm(parent, rot_matrices[2] * rot_matrices[1] * rot_matrices[0]) + + rot_vecs = [zeros(3, 1) for _ in range(3)] + for i, order in enumerate(rot_order): + rot_vecs[i][order - 1] = amounts[i].diff(dynamicsymbols._t) + u1, u2, u3 = rot_vecs[0] + rot_matrices[0].T * ( + rot_vecs[1] + rot_matrices[1].T * rot_vecs[2]) + wvec = u1 * self.x + u2 * self.y + u3 * self.z # There is a double - + self._ang_vel_dict.update({parent: wvec}) + parent._ang_vel_dict.update({self: -wvec}) + self._var_dict = {} + + def orient_quaternion(self, parent, numbers): + """Sets the orientation of this reference frame relative to a parent + reference frame via an orientation quaternion. An orientation + quaternion is defined as a finite rotation a unit vector, ``(lambda_x, + lambda_y, lambda_z)``, by an angle ``theta``. The orientation + quaternion is described by four parameters: + + - ``q0 = cos(theta/2)`` + - ``q1 = lambda_x*sin(theta/2)`` + - ``q2 = lambda_y*sin(theta/2)`` + - ``q3 = lambda_z*sin(theta/2)`` + + See `Quaternions and Spatial Rotation + `_ on + Wikipedia for more information. + + Parameters + ========== + parent : ReferenceFrame + Reference frame that this reference frame will be rotated relative + to. + numbers : 4-tuple of sympifiable + The four quaternion scalar numbers as defined above: ``q0``, + ``q1``, ``q2``, ``q3``. + + Warns + ====== + + UserWarning + If the orientation creates a kinematic loop. + + Examples + ======== + + Setup variables for the examples: + + >>> from sympy import symbols + >>> from sympy.physics.vector import ReferenceFrame + >>> q0, q1, q2, q3 = symbols('q0 q1 q2 q3') + >>> N = ReferenceFrame('N') + >>> B = ReferenceFrame('B') + + Set the orientation: + + >>> B.orient_quaternion(N, (q0, q1, q2, q3)) + >>> B.dcm(N) + Matrix([ + [q0**2 + q1**2 - q2**2 - q3**2, 2*q0*q3 + 2*q1*q2, -2*q0*q2 + 2*q1*q3], + [ -2*q0*q3 + 2*q1*q2, q0**2 - q1**2 + q2**2 - q3**2, 2*q0*q1 + 2*q2*q3], + [ 2*q0*q2 + 2*q1*q3, -2*q0*q1 + 2*q2*q3, q0**2 - q1**2 - q2**2 + q3**2]]) + + """ + + from sympy.physics.vector.functions import dynamicsymbols + _check_frame(parent) + + numbers = list(numbers) + for i, v in enumerate(numbers): + if not isinstance(v, Vector): + numbers[i] = sympify(v) + + if not (isinstance(numbers, (list, tuple)) & (len(numbers) == 4)): + raise TypeError('Amounts are a list or tuple of length 4') + q0, q1, q2, q3 = numbers + parent_orient_quaternion = ( + Matrix([[q0**2 + q1**2 - q2**2 - q3**2, + 2 * (q1 * q2 - q0 * q3), + 2 * (q0 * q2 + q1 * q3)], + [2 * (q1 * q2 + q0 * q3), + q0**2 - q1**2 + q2**2 - q3**2, + 2 * (q2 * q3 - q0 * q1)], + [2 * (q1 * q3 - q0 * q2), + 2 * (q0 * q1 + q2 * q3), + q0**2 - q1**2 - q2**2 + q3**2]])) + + self._dcm(parent, parent_orient_quaternion) + + t = dynamicsymbols._t + q0, q1, q2, q3 = numbers + q0d = diff(q0, t) + q1d = diff(q1, t) + q2d = diff(q2, t) + q3d = diff(q3, t) + w1 = 2 * (q1d * q0 + q2d * q3 - q3d * q2 - q0d * q1) + w2 = 2 * (q2d * q0 + q3d * q1 - q1d * q3 - q0d * q2) + w3 = 2 * (q3d * q0 + q1d * q2 - q2d * q1 - q0d * q3) + wvec = Vector([(Matrix([w1, w2, w3]), self)]) + + self._ang_vel_dict.update({parent: wvec}) + parent._ang_vel_dict.update({self: -wvec}) + self._var_dict = {} + + def orient(self, parent, rot_type, amounts, rot_order=''): + """Sets the orientation of this reference frame relative to another + (parent) reference frame. + + .. note:: It is now recommended to use the ``.orient_axis, + .orient_body_fixed, .orient_space_fixed, .orient_quaternion`` + methods for the different rotation types. + + Parameters + ========== + + parent : ReferenceFrame + Reference frame that this reference frame will be rotated relative + to. + rot_type : str + The method used to generate the direction cosine matrix. Supported + methods are: + + - ``'Axis'``: simple rotations about a single common axis + - ``'DCM'``: for setting the direction cosine matrix directly + - ``'Body'``: three successive rotations about new intermediate + axes, also called "Euler and Tait-Bryan angles" + - ``'Space'``: three successive rotations about the parent + frames' unit vectors + - ``'Quaternion'``: rotations defined by four parameters which + result in a singularity free direction cosine matrix + + amounts : + Expressions defining the rotation angles or direction cosine + matrix. These must match the ``rot_type``. See examples below for + details. The input types are: + + - ``'Axis'``: 2-tuple (expr/sym/func, Vector) + - ``'DCM'``: Matrix, shape(3,3) + - ``'Body'``: 3-tuple of expressions, symbols, or functions + - ``'Space'``: 3-tuple of expressions, symbols, or functions + - ``'Quaternion'``: 4-tuple of expressions, symbols, or + functions + + rot_order : str or int, optional + If applicable, the order of the successive of rotations. The string + ``'123'`` and integer ``123`` are equivalent, for example. Required + for ``'Body'`` and ``'Space'``. + + Warns + ====== + + UserWarning + If the orientation creates a kinematic loop. + + """ + + _check_frame(parent) + + approved_orders = ('123', '231', '312', '132', '213', '321', '121', + '131', '212', '232', '313', '323', '') + rot_order = translate(str(rot_order), 'XYZxyz', '123123') + rot_type = rot_type.upper() + + if rot_order not in approved_orders: + raise TypeError('The supplied order is not an approved type') + + if rot_type == 'AXIS': + self.orient_axis(parent, amounts[1], amounts[0]) + + elif rot_type == 'DCM': + self.orient_explicit(parent, amounts) + + elif rot_type == 'BODY': + self.orient_body_fixed(parent, amounts, rot_order) + + elif rot_type == 'SPACE': + self.orient_space_fixed(parent, amounts, rot_order) + + elif rot_type == 'QUATERNION': + self.orient_quaternion(parent, amounts) + + else: + raise NotImplementedError('That is not an implemented rotation') + + def orientnew(self, newname, rot_type, amounts, rot_order='', + variables=None, indices=None, latexs=None): + r"""Returns a new reference frame oriented with respect to this + reference frame. + + See ``ReferenceFrame.orient()`` for detailed examples of how to orient + reference frames. + + Parameters + ========== + + newname : str + Name for the new reference frame. + rot_type : str + The method used to generate the direction cosine matrix. Supported + methods are: + + - ``'Axis'``: simple rotations about a single common axis + - ``'DCM'``: for setting the direction cosine matrix directly + - ``'Body'``: three successive rotations about new intermediate + axes, also called "Euler and Tait-Bryan angles" + - ``'Space'``: three successive rotations about the parent + frames' unit vectors + - ``'Quaternion'``: rotations defined by four parameters which + result in a singularity free direction cosine matrix + + amounts : + Expressions defining the rotation angles or direction cosine + matrix. These must match the ``rot_type``. See examples below for + details. The input types are: + + - ``'Axis'``: 2-tuple (expr/sym/func, Vector) + - ``'DCM'``: Matrix, shape(3,3) + - ``'Body'``: 3-tuple of expressions, symbols, or functions + - ``'Space'``: 3-tuple of expressions, symbols, or functions + - ``'Quaternion'``: 4-tuple of expressions, symbols, or + functions + + rot_order : str or int, optional + If applicable, the order of the successive of rotations. The string + ``'123'`` and integer ``123`` are equivalent, for example. Required + for ``'Body'`` and ``'Space'``. + indices : tuple of str + Enables the reference frame's basis unit vectors to be accessed by + Python's square bracket indexing notation using the provided three + indice strings and alters the printing of the unit vectors to + reflect this choice. + latexs : tuple of str + Alters the LaTeX printing of the reference frame's basis unit + vectors to the provided three valid LaTeX strings. + + Examples + ======== + + >>> from sympy import symbols + >>> from sympy.physics.vector import ReferenceFrame, vlatex + >>> q0, q1, q2, q3 = symbols('q0 q1 q2 q3') + >>> N = ReferenceFrame('N') + + Create a new reference frame A rotated relative to N through a simple + rotation. + + >>> A = N.orientnew('A', 'Axis', (q0, N.x)) + + Create a new reference frame B rotated relative to N through body-fixed + rotations. + + >>> B = N.orientnew('B', 'Body', (q1, q2, q3), '123') + + Create a new reference frame C rotated relative to N through a simple + rotation with unique indices and LaTeX printing. + + >>> C = N.orientnew('C', 'Axis', (q0, N.x), indices=('1', '2', '3'), + ... latexs=(r'\hat{\mathbf{c}}_1',r'\hat{\mathbf{c}}_2', + ... r'\hat{\mathbf{c}}_3')) + >>> C['1'] + C['1'] + >>> print(vlatex(C['1'])) + \hat{\mathbf{c}}_1 + + """ + + newframe = self.__class__(newname, variables=variables, + indices=indices, latexs=latexs) + + approved_orders = ('123', '231', '312', '132', '213', '321', '121', + '131', '212', '232', '313', '323', '') + rot_order = translate(str(rot_order), 'XYZxyz', '123123') + rot_type = rot_type.upper() + + if rot_order not in approved_orders: + raise TypeError('The supplied order is not an approved type') + + if rot_type == 'AXIS': + newframe.orient_axis(self, amounts[1], amounts[0]) + + elif rot_type == 'DCM': + newframe.orient_explicit(self, amounts) + + elif rot_type == 'BODY': + newframe.orient_body_fixed(self, amounts, rot_order) + + elif rot_type == 'SPACE': + newframe.orient_space_fixed(self, amounts, rot_order) + + elif rot_type == 'QUATERNION': + newframe.orient_quaternion(self, amounts) + + else: + raise NotImplementedError('That is not an implemented rotation') + return newframe + + def set_ang_acc(self, otherframe, value): + """Define the angular acceleration Vector in a ReferenceFrame. + + Defines the angular acceleration of this ReferenceFrame, in another. + Angular acceleration can be defined with respect to multiple different + ReferenceFrames. Care must be taken to not create loops which are + inconsistent. + + Parameters + ========== + + otherframe : ReferenceFrame + A ReferenceFrame to define the angular acceleration in + value : Vector + The Vector representing angular acceleration + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> N = ReferenceFrame('N') + >>> A = ReferenceFrame('A') + >>> V = 10 * N.x + >>> A.set_ang_acc(N, V) + >>> A.ang_acc_in(N) + 10*N.x + + """ + + if value == 0: + value = Vector(0) + value = _check_vector(value) + _check_frame(otherframe) + self._ang_acc_dict.update({otherframe: value}) + otherframe._ang_acc_dict.update({self: -value}) + + def set_ang_vel(self, otherframe, value): + """Define the angular velocity vector in a ReferenceFrame. + + Defines the angular velocity of this ReferenceFrame, in another. + Angular velocity can be defined with respect to multiple different + ReferenceFrames. Care must be taken to not create loops which are + inconsistent. + + Parameters + ========== + + otherframe : ReferenceFrame + A ReferenceFrame to define the angular velocity in + value : Vector + The Vector representing angular velocity + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> N = ReferenceFrame('N') + >>> A = ReferenceFrame('A') + >>> V = 10 * N.x + >>> A.set_ang_vel(N, V) + >>> A.ang_vel_in(N) + 10*N.x + + """ + + if value == 0: + value = Vector(0) + value = _check_vector(value) + _check_frame(otherframe) + self._ang_vel_dict.update({otherframe: value}) + otherframe._ang_vel_dict.update({self: -value}) + + @property + def x(self): + """The basis Vector for the ReferenceFrame, in the x direction. """ + return self._x + + @property + def y(self): + """The basis Vector for the ReferenceFrame, in the y direction. """ + return self._y + + @property + def z(self): + """The basis Vector for the ReferenceFrame, in the z direction. """ + return self._z + + @property + def xx(self): + """Unit dyad of basis Vectors x and x for the ReferenceFrame.""" + return Vector.outer(self.x, self.x) + + @property + def xy(self): + """Unit dyad of basis Vectors x and y for the ReferenceFrame.""" + return Vector.outer(self.x, self.y) + + @property + def xz(self): + """Unit dyad of basis Vectors x and z for the ReferenceFrame.""" + return Vector.outer(self.x, self.z) + + @property + def yx(self): + """Unit dyad of basis Vectors y and x for the ReferenceFrame.""" + return Vector.outer(self.y, self.x) + + @property + def yy(self): + """Unit dyad of basis Vectors y and y for the ReferenceFrame.""" + return Vector.outer(self.y, self.y) + + @property + def yz(self): + """Unit dyad of basis Vectors y and z for the ReferenceFrame.""" + return Vector.outer(self.y, self.z) + + @property + def zx(self): + """Unit dyad of basis Vectors z and x for the ReferenceFrame.""" + return Vector.outer(self.z, self.x) + + @property + def zy(self): + """Unit dyad of basis Vectors z and y for the ReferenceFrame.""" + return Vector.outer(self.z, self.y) + + @property + def zz(self): + """Unit dyad of basis Vectors z and z for the ReferenceFrame.""" + return Vector.outer(self.z, self.z) + + @property + def u(self): + """Unit dyadic for the ReferenceFrame.""" + return self.xx + self.yy + self.zz + + def partial_velocity(self, frame, *gen_speeds): + """Returns the partial angular velocities of this frame in the given + frame with respect to one or more provided generalized speeds. + + Parameters + ========== + frame : ReferenceFrame + The frame with which the angular velocity is defined in. + gen_speeds : functions of time + The generalized speeds. + + Returns + ======= + partial_velocities : tuple of Vector + The partial angular velocity vectors corresponding to the provided + generalized speeds. + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, dynamicsymbols + >>> N = ReferenceFrame('N') + >>> A = ReferenceFrame('A') + >>> u1, u2 = dynamicsymbols('u1, u2') + >>> A.set_ang_vel(N, u1 * A.x + u2 * N.y) + >>> A.partial_velocity(N, u1) + A.x + >>> A.partial_velocity(N, u1, u2) + (A.x, N.y) + + """ + + from sympy.physics.vector.functions import partial_velocity + + vel = self.ang_vel_in(frame) + partials = partial_velocity([vel], gen_speeds, frame)[0] + + if len(partials) == 1: + return partials[0] + else: + return tuple(partials) + + +def _check_frame(other): + from .vector import VectorTypeError + if not isinstance(other, ReferenceFrame): + raise VectorTypeError(other, ReferenceFrame('A')) diff --git a/lib/python3.12/site-packages/sympy/physics/vector/functions.py b/lib/python3.12/site-packages/sympy/physics/vector/functions.py new file mode 100644 index 0000000000000000000000000000000000000000..6775b4b23bb376992d6a9e7651ba73a951c84287 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/functions.py @@ -0,0 +1,650 @@ +from functools import reduce + +from sympy import (sympify, diff, sin, cos, Matrix, symbols, + Function, S, Symbol, linear_eq_to_matrix) +from sympy.integrals.integrals import integrate +from sympy.simplify.trigsimp import trigsimp +from .vector import Vector, _check_vector +from .frame import CoordinateSym, _check_frame +from .dyadic import Dyadic +from .printing import vprint, vsprint, vpprint, vlatex, init_vprinting +from sympy.utilities.iterables import iterable +from sympy.utilities.misc import translate + +__all__ = ['cross', 'dot', 'express', 'time_derivative', 'outer', + 'kinematic_equations', 'get_motion_params', 'partial_velocity', + 'dynamicsymbols', 'vprint', 'vsprint', 'vpprint', 'vlatex', + 'init_vprinting'] + + +def cross(vec1, vec2): + """Cross product convenience wrapper for Vector.cross(): \n""" + if not isinstance(vec1, (Vector, Dyadic)): + raise TypeError('Cross product is between two vectors') + return vec1 ^ vec2 + + +cross.__doc__ += Vector.cross.__doc__ # type: ignore + + +def dot(vec1, vec2): + """Dot product convenience wrapper for Vector.dot(): \n""" + if not isinstance(vec1, (Vector, Dyadic)): + raise TypeError('Dot product is between two vectors') + return vec1 & vec2 + + +dot.__doc__ += Vector.dot.__doc__ # type: ignore + + +def express(expr, frame, frame2=None, variables=False): + """ + Global function for 'express' functionality. + + Re-expresses a Vector, scalar(sympyfiable) or Dyadic in given frame. + + Refer to the local methods of Vector and Dyadic for details. + If 'variables' is True, then the coordinate variables (CoordinateSym + instances) of other frames present in the vector/scalar field or + dyadic expression are also substituted in terms of the base scalars of + this frame. + + Parameters + ========== + + expr : Vector/Dyadic/scalar(sympyfiable) + The expression to re-express in ReferenceFrame 'frame' + + frame: ReferenceFrame + The reference frame to express expr in + + frame2 : ReferenceFrame + The other frame required for re-expression(only for Dyadic expr) + + variables : boolean + Specifies whether to substitute the coordinate variables present + in expr, in terms of those of frame + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, outer, dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> N = ReferenceFrame('N') + >>> q = dynamicsymbols('q') + >>> B = N.orientnew('B', 'Axis', [q, N.z]) + >>> d = outer(N.x, N.x) + >>> from sympy.physics.vector import express + >>> express(d, B, N) + cos(q)*(B.x|N.x) - sin(q)*(B.y|N.x) + >>> express(B.x, N) + cos(q)*N.x + sin(q)*N.y + >>> express(N[0], B, variables=True) + B_x*cos(q) - B_y*sin(q) + + """ + + _check_frame(frame) + + if expr == 0: + return expr + + if isinstance(expr, Vector): + # Given expr is a Vector + if variables: + # If variables attribute is True, substitute the coordinate + # variables in the Vector + frame_list = [x[-1] for x in expr.args] + subs_dict = {} + for f in frame_list: + subs_dict.update(f.variable_map(frame)) + expr = expr.subs(subs_dict) + # Re-express in this frame + outvec = Vector([]) + for v in expr.args: + if v[1] != frame: + temp = frame.dcm(v[1]) * v[0] + if Vector.simp: + temp = temp.applyfunc(lambda x: + trigsimp(x, method='fu')) + outvec += Vector([(temp, frame)]) + else: + outvec += Vector([v]) + return outvec + + if isinstance(expr, Dyadic): + if frame2 is None: + frame2 = frame + _check_frame(frame2) + ol = Dyadic(0) + for v in expr.args: + ol += express(v[0], frame, variables=variables) * \ + (express(v[1], frame, variables=variables) | + express(v[2], frame2, variables=variables)) + return ol + + else: + if variables: + # Given expr is a scalar field + frame_set = set() + expr = sympify(expr) + # Substitute all the coordinate variables + for x in expr.free_symbols: + if isinstance(x, CoordinateSym) and x.frame != frame: + frame_set.add(x.frame) + subs_dict = {} + for f in frame_set: + subs_dict.update(f.variable_map(frame)) + return expr.subs(subs_dict) + return expr + + +def time_derivative(expr, frame, order=1): + """ + Calculate the time derivative of a vector/scalar field function + or dyadic expression in given frame. + + References + ========== + + https://en.wikipedia.org/wiki/Rotating_reference_frame#Time_derivatives_in_the_two_frames + + Parameters + ========== + + expr : Vector/Dyadic/sympifyable + The expression whose time derivative is to be calculated + + frame : ReferenceFrame + The reference frame to calculate the time derivative in + + order : integer + The order of the derivative to be calculated + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> from sympy import Symbol + >>> q1 = Symbol('q1') + >>> u1 = dynamicsymbols('u1') + >>> N = ReferenceFrame('N') + >>> A = N.orientnew('A', 'Axis', [q1, N.x]) + >>> v = u1 * N.x + >>> A.set_ang_vel(N, 10*A.x) + >>> from sympy.physics.vector import time_derivative + >>> time_derivative(v, N) + u1'*N.x + >>> time_derivative(u1*A[0], N) + N_x*u1' + >>> B = N.orientnew('B', 'Axis', [u1, N.z]) + >>> from sympy.physics.vector import outer + >>> d = outer(N.x, N.x) + >>> time_derivative(d, B) + - u1'*(N.y|N.x) - u1'*(N.x|N.y) + + """ + + t = dynamicsymbols._t + _check_frame(frame) + + if order == 0: + return expr + if order % 1 != 0 or order < 0: + raise ValueError("Unsupported value of order entered") + + if isinstance(expr, Vector): + outlist = [] + for v in expr.args: + if v[1] == frame: + outlist += [(express(v[0], frame, variables=True).diff(t), + frame)] + else: + outlist += (time_derivative(Vector([v]), v[1]) + + (v[1].ang_vel_in(frame) ^ Vector([v]))).args + outvec = Vector(outlist) + return time_derivative(outvec, frame, order - 1) + + if isinstance(expr, Dyadic): + ol = Dyadic(0) + for v in expr.args: + ol += (v[0].diff(t) * (v[1] | v[2])) + ol += (v[0] * (time_derivative(v[1], frame) | v[2])) + ol += (v[0] * (v[1] | time_derivative(v[2], frame))) + return time_derivative(ol, frame, order - 1) + + else: + return diff(express(expr, frame, variables=True), t, order) + + +def outer(vec1, vec2): + """Outer product convenience wrapper for Vector.outer():\n""" + if not isinstance(vec1, Vector): + raise TypeError('Outer product is between two Vectors') + return vec1.outer(vec2) + + +outer.__doc__ += Vector.outer.__doc__ # type: ignore + + +def kinematic_equations(speeds, coords, rot_type, rot_order=''): + """Gives equations relating the qdot's to u's for a rotation type. + + Supply rotation type and order as in orient. Speeds are assumed to be + body-fixed; if we are defining the orientation of B in A using by rot_type, + the angular velocity of B in A is assumed to be in the form: speed[0]*B.x + + speed[1]*B.y + speed[2]*B.z + + Parameters + ========== + + speeds : list of length 3 + The body fixed angular velocity measure numbers. + coords : list of length 3 or 4 + The coordinates used to define the orientation of the two frames. + rot_type : str + The type of rotation used to create the equations. Body, Space, or + Quaternion only + rot_order : str or int + If applicable, the order of a series of rotations. + + Examples + ======== + + >>> from sympy.physics.vector import dynamicsymbols + >>> from sympy.physics.vector import kinematic_equations, vprint + >>> u1, u2, u3 = dynamicsymbols('u1 u2 u3') + >>> q1, q2, q3 = dynamicsymbols('q1 q2 q3') + >>> vprint(kinematic_equations([u1,u2,u3], [q1,q2,q3], 'body', '313'), + ... order=None) + [-(u1*sin(q3) + u2*cos(q3))/sin(q2) + q1', -u1*cos(q3) + u2*sin(q3) + q2', (u1*sin(q3) + u2*cos(q3))*cos(q2)/sin(q2) - u3 + q3'] + + """ + + # Code below is checking and sanitizing input + approved_orders = ('123', '231', '312', '132', '213', '321', '121', '131', + '212', '232', '313', '323', '1', '2', '3', '') + # make sure XYZ => 123 and rot_type is in lower case + rot_order = translate(str(rot_order), 'XYZxyz', '123123') + rot_type = rot_type.lower() + + if not isinstance(speeds, (list, tuple)): + raise TypeError('Need to supply speeds in a list') + if len(speeds) != 3: + raise TypeError('Need to supply 3 body-fixed speeds') + if not isinstance(coords, (list, tuple)): + raise TypeError('Need to supply coordinates in a list') + if rot_type in ['body', 'space']: + if rot_order not in approved_orders: + raise ValueError('Not an acceptable rotation order') + if len(coords) != 3: + raise ValueError('Need 3 coordinates for body or space') + # Actual hard-coded kinematic differential equations + w1, w2, w3 = speeds + if w1 == w2 == w3 == 0: + return [S.Zero]*3 + q1, q2, q3 = coords + q1d, q2d, q3d = [diff(i, dynamicsymbols._t) for i in coords] + s1, s2, s3 = [sin(q1), sin(q2), sin(q3)] + c1, c2, c3 = [cos(q1), cos(q2), cos(q3)] + if rot_type == 'body': + if rot_order == '123': + return [q1d - (w1 * c3 - w2 * s3) / c2, q2d - w1 * s3 - w2 * + c3, q3d - (-w1 * c3 + w2 * s3) * s2 / c2 - w3] + if rot_order == '231': + return [q1d - (w2 * c3 - w3 * s3) / c2, q2d - w2 * s3 - w3 * + c3, q3d - w1 - (- w2 * c3 + w3 * s3) * s2 / c2] + if rot_order == '312': + return [q1d - (-w1 * s3 + w3 * c3) / c2, q2d - w1 * c3 - w3 * + s3, q3d - (w1 * s3 - w3 * c3) * s2 / c2 - w2] + if rot_order == '132': + return [q1d - (w1 * c3 + w3 * s3) / c2, q2d + w1 * s3 - w3 * + c3, q3d - (w1 * c3 + w3 * s3) * s2 / c2 - w2] + if rot_order == '213': + return [q1d - (w1 * s3 + w2 * c3) / c2, q2d - w1 * c3 + w2 * + s3, q3d - (w1 * s3 + w2 * c3) * s2 / c2 - w3] + if rot_order == '321': + return [q1d - (w2 * s3 + w3 * c3) / c2, q2d - w2 * c3 + w3 * + s3, q3d - w1 - (w2 * s3 + w3 * c3) * s2 / c2] + if rot_order == '121': + return [q1d - (w2 * s3 + w3 * c3) / s2, q2d - w2 * c3 + w3 * + s3, q3d - w1 + (w2 * s3 + w3 * c3) * c2 / s2] + if rot_order == '131': + return [q1d - (-w2 * c3 + w3 * s3) / s2, q2d - w2 * s3 - w3 * + c3, q3d - w1 - (w2 * c3 - w3 * s3) * c2 / s2] + if rot_order == '212': + return [q1d - (w1 * s3 - w3 * c3) / s2, q2d - w1 * c3 - w3 * + s3, q3d - (-w1 * s3 + w3 * c3) * c2 / s2 - w2] + if rot_order == '232': + return [q1d - (w1 * c3 + w3 * s3) / s2, q2d + w1 * s3 - w3 * + c3, q3d + (w1 * c3 + w3 * s3) * c2 / s2 - w2] + if rot_order == '313': + return [q1d - (w1 * s3 + w2 * c3) / s2, q2d - w1 * c3 + w2 * + s3, q3d + (w1 * s3 + w2 * c3) * c2 / s2 - w3] + if rot_order == '323': + return [q1d - (-w1 * c3 + w2 * s3) / s2, q2d - w1 * s3 - w2 * + c3, q3d - (w1 * c3 - w2 * s3) * c2 / s2 - w3] + if rot_type == 'space': + if rot_order == '123': + return [q1d - w1 - (w2 * s1 + w3 * c1) * s2 / c2, q2d - w2 * + c1 + w3 * s1, q3d - (w2 * s1 + w3 * c1) / c2] + if rot_order == '231': + return [q1d - (w1 * c1 + w3 * s1) * s2 / c2 - w2, q2d + w1 * + s1 - w3 * c1, q3d - (w1 * c1 + w3 * s1) / c2] + if rot_order == '312': + return [q1d - (w1 * s1 + w2 * c1) * s2 / c2 - w3, q2d - w1 * + c1 + w2 * s1, q3d - (w1 * s1 + w2 * c1) / c2] + if rot_order == '132': + return [q1d - w1 - (-w2 * c1 + w3 * s1) * s2 / c2, q2d - w2 * + s1 - w3 * c1, q3d - (w2 * c1 - w3 * s1) / c2] + if rot_order == '213': + return [q1d - (w1 * s1 - w3 * c1) * s2 / c2 - w2, q2d - w1 * + c1 - w3 * s1, q3d - (-w1 * s1 + w3 * c1) / c2] + if rot_order == '321': + return [q1d - (-w1 * c1 + w2 * s1) * s2 / c2 - w3, q2d - w1 * + s1 - w2 * c1, q3d - (w1 * c1 - w2 * s1) / c2] + if rot_order == '121': + return [q1d - w1 + (w2 * s1 + w3 * c1) * c2 / s2, q2d - w2 * + c1 + w3 * s1, q3d - (w2 * s1 + w3 * c1) / s2] + if rot_order == '131': + return [q1d - w1 - (w2 * c1 - w3 * s1) * c2 / s2, q2d - w2 * + s1 - w3 * c1, q3d - (-w2 * c1 + w3 * s1) / s2] + if rot_order == '212': + return [q1d - (-w1 * s1 + w3 * c1) * c2 / s2 - w2, q2d - w1 * + c1 - w3 * s1, q3d - (w1 * s1 - w3 * c1) / s2] + if rot_order == '232': + return [q1d + (w1 * c1 + w3 * s1) * c2 / s2 - w2, q2d + w1 * + s1 - w3 * c1, q3d - (w1 * c1 + w3 * s1) / s2] + if rot_order == '313': + return [q1d + (w1 * s1 + w2 * c1) * c2 / s2 - w3, q2d - w1 * + c1 + w2 * s1, q3d - (w1 * s1 + w2 * c1) / s2] + if rot_order == '323': + return [q1d - (w1 * c1 - w2 * s1) * c2 / s2 - w3, q2d - w1 * + s1 - w2 * c1, q3d - (-w1 * c1 + w2 * s1) / s2] + elif rot_type == 'quaternion': + if rot_order != '': + raise ValueError('Cannot have rotation order for quaternion') + if len(coords) != 4: + raise ValueError('Need 4 coordinates for quaternion') + # Actual hard-coded kinematic differential equations + e0, e1, e2, e3 = coords + w = Matrix(speeds + [0]) + E = Matrix([[e0, -e3, e2, e1], + [e3, e0, -e1, e2], + [-e2, e1, e0, e3], + [-e1, -e2, -e3, e0]]) + edots = Matrix([diff(i, dynamicsymbols._t) for i in [e1, e2, e3, e0]]) + return list(edots.T - 0.5 * w.T * E.T) + else: + raise ValueError('Not an approved rotation type for this function') + + +def get_motion_params(frame, **kwargs): + """ + Returns the three motion parameters - (acceleration, velocity, and + position) as vectorial functions of time in the given frame. + + If a higher order differential function is provided, the lower order + functions are used as boundary conditions. For example, given the + acceleration, the velocity and position parameters are taken as + boundary conditions. + + The values of time at which the boundary conditions are specified + are taken from timevalue1(for position boundary condition) and + timevalue2(for velocity boundary condition). + + If any of the boundary conditions are not provided, they are taken + to be zero by default (zero vectors, in case of vectorial inputs). If + the boundary conditions are also functions of time, they are converted + to constants by substituting the time values in the dynamicsymbols._t + time Symbol. + + This function can also be used for calculating rotational motion + parameters. Have a look at the Parameters and Examples for more clarity. + + Parameters + ========== + + frame : ReferenceFrame + The frame to express the motion parameters in + + acceleration : Vector + Acceleration of the object/frame as a function of time + + velocity : Vector + Velocity as function of time or as boundary condition + of velocity at time = timevalue1 + + position : Vector + Velocity as function of time or as boundary condition + of velocity at time = timevalue1 + + timevalue1 : sympyfiable + Value of time for position boundary condition + + timevalue2 : sympyfiable + Value of time for velocity boundary condition + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, get_motion_params, dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> from sympy import symbols + >>> R = ReferenceFrame('R') + >>> v1, v2, v3 = dynamicsymbols('v1 v2 v3') + >>> v = v1*R.x + v2*R.y + v3*R.z + >>> get_motion_params(R, position = v) + (v1''*R.x + v2''*R.y + v3''*R.z, v1'*R.x + v2'*R.y + v3'*R.z, v1*R.x + v2*R.y + v3*R.z) + >>> a, b, c = symbols('a b c') + >>> v = a*R.x + b*R.y + c*R.z + >>> get_motion_params(R, velocity = v) + (0, a*R.x + b*R.y + c*R.z, a*t*R.x + b*t*R.y + c*t*R.z) + >>> parameters = get_motion_params(R, acceleration = v) + >>> parameters[1] + a*t*R.x + b*t*R.y + c*t*R.z + >>> parameters[2] + a*t**2/2*R.x + b*t**2/2*R.y + c*t**2/2*R.z + + """ + + def _process_vector_differential(vectdiff, condition, variable, ordinate, + frame): + """ + Helper function for get_motion methods. Finds derivative of vectdiff + wrt variable, and its integral using the specified boundary condition + at value of variable = ordinate. + Returns a tuple of - (derivative, function and integral) wrt vectdiff + + """ + + # Make sure boundary condition is independent of 'variable' + if condition != 0: + condition = express(condition, frame, variables=True) + # Special case of vectdiff == 0 + if vectdiff == Vector(0): + return (0, 0, condition) + # Express vectdiff completely in condition's frame to give vectdiff1 + vectdiff1 = express(vectdiff, frame) + # Find derivative of vectdiff + vectdiff2 = time_derivative(vectdiff, frame) + # Integrate and use boundary condition + vectdiff0 = Vector(0) + lims = (variable, ordinate, variable) + for dim in frame: + function1 = vectdiff1.dot(dim) + abscissa = dim.dot(condition).subs({variable: ordinate}) + # Indefinite integral of 'function1' wrt 'variable', using + # the given initial condition (ordinate, abscissa). + vectdiff0 += (integrate(function1, lims) + abscissa) * dim + # Return tuple + return (vectdiff2, vectdiff, vectdiff0) + + _check_frame(frame) + # Decide mode of operation based on user's input + if 'acceleration' in kwargs: + mode = 2 + elif 'velocity' in kwargs: + mode = 1 + else: + mode = 0 + # All the possible parameters in kwargs + # Not all are required for every case + # If not specified, set to default values(may or may not be used in + # calculations) + conditions = ['acceleration', 'velocity', 'position', + 'timevalue', 'timevalue1', 'timevalue2'] + for i, x in enumerate(conditions): + if x not in kwargs: + if i < 3: + kwargs[x] = Vector(0) + else: + kwargs[x] = S.Zero + elif i < 3: + _check_vector(kwargs[x]) + else: + kwargs[x] = sympify(kwargs[x]) + if mode == 2: + vel = _process_vector_differential(kwargs['acceleration'], + kwargs['velocity'], + dynamicsymbols._t, + kwargs['timevalue2'], frame)[2] + pos = _process_vector_differential(vel, kwargs['position'], + dynamicsymbols._t, + kwargs['timevalue1'], frame)[2] + return (kwargs['acceleration'], vel, pos) + elif mode == 1: + return _process_vector_differential(kwargs['velocity'], + kwargs['position'], + dynamicsymbols._t, + kwargs['timevalue1'], frame) + else: + vel = time_derivative(kwargs['position'], frame) + acc = time_derivative(vel, frame) + return (acc, vel, kwargs['position']) + + +def partial_velocity(vel_vecs, gen_speeds, frame): + """Returns a list of partial velocities with respect to the provided + generalized speeds in the given reference frame for each of the supplied + velocity vectors. + + The output is a list of lists. The outer list has a number of elements + equal to the number of supplied velocity vectors. The inner lists are, for + each velocity vector, the partial derivatives of that velocity vector with + respect to the generalized speeds supplied. + + Parameters + ========== + + vel_vecs : iterable + An iterable of velocity vectors (angular or linear). + gen_speeds : iterable + An iterable of generalized speeds. + frame : ReferenceFrame + The reference frame that the partial derivatives are going to be taken + in. + + Examples + ======== + + >>> from sympy.physics.vector import Point, ReferenceFrame + >>> from sympy.physics.vector import dynamicsymbols + >>> from sympy.physics.vector import partial_velocity + >>> u = dynamicsymbols('u') + >>> N = ReferenceFrame('N') + >>> P = Point('P') + >>> P.set_vel(N, u * N.x) + >>> vel_vecs = [P.vel(N)] + >>> gen_speeds = [u] + >>> partial_velocity(vel_vecs, gen_speeds, N) + [[N.x]] + + """ + + if not iterable(vel_vecs): + raise TypeError('Velocity vectors must be contained in an iterable.') + + if not iterable(gen_speeds): + raise TypeError('Generalized speeds must be contained in an iterable') + + vec_partials = [] + gen_speeds = list(gen_speeds) + for vel in vel_vecs: + partials = [Vector(0) for _ in gen_speeds] + for components, ref in vel.args: + mat, _ = linear_eq_to_matrix(components, gen_speeds) + for i in range(len(gen_speeds)): + for dim, direction in enumerate(ref): + if mat[dim, i] != 0: + partials[i] += direction * mat[dim, i] + + vec_partials.append(partials) + + return vec_partials + + +def dynamicsymbols(names, level=0, **assumptions): + """Uses symbols and Function for functions of time. + + Creates a SymPy UndefinedFunction, which is then initialized as a function + of a variable, the default being Symbol('t'). + + Parameters + ========== + + names : str + Names of the dynamic symbols you want to create; works the same way as + inputs to symbols + level : int + Level of differentiation of the returned function; d/dt once of t, + twice of t, etc. + assumptions : + - real(bool) : This is used to set the dynamicsymbol as real, + by default is False. + - positive(bool) : This is used to set the dynamicsymbol as positive, + by default is False. + - commutative(bool) : This is used to set the commutative property of + a dynamicsymbol, by default is True. + - integer(bool) : This is used to set the dynamicsymbol as integer, + by default is False. + + Examples + ======== + + >>> from sympy.physics.vector import dynamicsymbols + >>> from sympy import diff, Symbol + >>> q1 = dynamicsymbols('q1') + >>> q1 + q1(t) + >>> q2 = dynamicsymbols('q2', real=True) + >>> q2.is_real + True + >>> q3 = dynamicsymbols('q3', positive=True) + >>> q3.is_positive + True + >>> q4, q5 = dynamicsymbols('q4,q5', commutative=False) + >>> bool(q4*q5 != q5*q4) + True + >>> q6 = dynamicsymbols('q6', integer=True) + >>> q6.is_integer + True + >>> diff(q1, Symbol('t')) + Derivative(q1(t), t) + + """ + esses = symbols(names, cls=Function, **assumptions) + t = dynamicsymbols._t + if iterable(esses): + esses = [reduce(diff, [t] * level, e(t)) for e in esses] + return esses + else: + return reduce(diff, [t] * level, esses(t)) + + +dynamicsymbols._t = Symbol('t') # type: ignore +dynamicsymbols._str = '\'' # type: ignore diff --git a/lib/python3.12/site-packages/sympy/physics/vector/point.py b/lib/python3.12/site-packages/sympy/physics/vector/point.py new file mode 100644 index 0000000000000000000000000000000000000000..39d61aa89694fbd7e3eca21b15fc658b379782fb --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/point.py @@ -0,0 +1,635 @@ +from .vector import Vector, _check_vector +from .frame import _check_frame +from warnings import warn +from sympy.utilities.misc import filldedent + +__all__ = ['Point'] + + +class Point: + """This object represents a point in a dynamic system. + + It stores the: position, velocity, and acceleration of a point. + The position is a vector defined as the vector distance from a parent + point to this point. + + Parameters + ========== + + name : string + The display name of the Point + + Examples + ======== + + >>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> N = ReferenceFrame('N') + >>> O = Point('O') + >>> P = Point('P') + >>> u1, u2, u3 = dynamicsymbols('u1 u2 u3') + >>> O.set_vel(N, u1 * N.x + u2 * N.y + u3 * N.z) + >>> O.acc(N) + u1'*N.x + u2'*N.y + u3'*N.z + + ``symbols()`` can be used to create multiple Points in a single step, for + example: + + >>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> from sympy import symbols + >>> N = ReferenceFrame('N') + >>> u1, u2 = dynamicsymbols('u1 u2') + >>> A, B = symbols('A B', cls=Point) + >>> type(A) + + >>> A.set_vel(N, u1 * N.x + u2 * N.y) + >>> B.set_vel(N, u2 * N.x + u1 * N.y) + >>> A.acc(N) - B.acc(N) + (u1' - u2')*N.x + (-u1' + u2')*N.y + + """ + + def __init__(self, name): + """Initialization of a Point object. """ + self.name = name + self._pos_dict = {} + self._vel_dict = {} + self._acc_dict = {} + self._pdlist = [self._pos_dict, self._vel_dict, self._acc_dict] + + def __str__(self): + return self.name + + __repr__ = __str__ + + def _check_point(self, other): + if not isinstance(other, Point): + raise TypeError('A Point must be supplied') + + def _pdict_list(self, other, num): + """Returns a list of points that gives the shortest path with respect + to position, velocity, or acceleration from this point to the provided + point. + + Parameters + ========== + other : Point + A point that may be related to this point by position, velocity, or + acceleration. + num : integer + 0 for searching the position tree, 1 for searching the velocity + tree, and 2 for searching the acceleration tree. + + Returns + ======= + list of Points + A sequence of points from self to other. + + Notes + ===== + + It is not clear if num = 1 or num = 2 actually works because the keys + to ``_vel_dict`` and ``_acc_dict`` are :class:`ReferenceFrame` objects + which do not have the ``_pdlist`` attribute. + + """ + outlist = [[self]] + oldlist = [[]] + while outlist != oldlist: + oldlist = outlist[:] + for v in outlist: + templist = v[-1]._pdlist[num].keys() + for v2 in templist: + if not v.__contains__(v2): + littletemplist = v + [v2] + if not outlist.__contains__(littletemplist): + outlist.append(littletemplist) + for v in oldlist: + if v[-1] != other: + outlist.remove(v) + outlist.sort(key=len) + if len(outlist) != 0: + return outlist[0] + raise ValueError('No Connecting Path found between ' + other.name + + ' and ' + self.name) + + def a1pt_theory(self, otherpoint, outframe, interframe): + """Sets the acceleration of this point with the 1-point theory. + + The 1-point theory for point acceleration looks like this: + + ^N a^P = ^B a^P + ^N a^O + ^N alpha^B x r^OP + ^N omega^B x (^N omega^B + x r^OP) + 2 ^N omega^B x ^B v^P + + where O is a point fixed in B, P is a point moving in B, and B is + rotating in frame N. + + Parameters + ========== + + otherpoint : Point + The first point of the 1-point theory (O) + outframe : ReferenceFrame + The frame we want this point's acceleration defined in (N) + fixedframe : ReferenceFrame + The intermediate frame in this calculation (B) + + Examples + ======== + + >>> from sympy.physics.vector import Point, ReferenceFrame + >>> from sympy.physics.vector import dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> q = dynamicsymbols('q') + >>> q2 = dynamicsymbols('q2') + >>> qd = dynamicsymbols('q', 1) + >>> q2d = dynamicsymbols('q2', 1) + >>> N = ReferenceFrame('N') + >>> B = ReferenceFrame('B') + >>> B.set_ang_vel(N, 5 * B.y) + >>> O = Point('O') + >>> P = O.locatenew('P', q * B.x + q2 * B.y) + >>> P.set_vel(B, qd * B.x + q2d * B.y) + >>> O.set_vel(N, 0) + >>> P.a1pt_theory(O, N, B) + (-25*q + q'')*B.x + q2''*B.y - 10*q'*B.z + + """ + + _check_frame(outframe) + _check_frame(interframe) + self._check_point(otherpoint) + dist = self.pos_from(otherpoint) + v = self.vel(interframe) + a1 = otherpoint.acc(outframe) + a2 = self.acc(interframe) + omega = interframe.ang_vel_in(outframe) + alpha = interframe.ang_acc_in(outframe) + self.set_acc(outframe, a2 + 2 * (omega.cross(v)) + a1 + + (alpha.cross(dist)) + (omega.cross(omega.cross(dist)))) + return self.acc(outframe) + + def a2pt_theory(self, otherpoint, outframe, fixedframe): + """Sets the acceleration of this point with the 2-point theory. + + The 2-point theory for point acceleration looks like this: + + ^N a^P = ^N a^O + ^N alpha^B x r^OP + ^N omega^B x (^N omega^B x r^OP) + + where O and P are both points fixed in frame B, which is rotating in + frame N. + + Parameters + ========== + + otherpoint : Point + The first point of the 2-point theory (O) + outframe : ReferenceFrame + The frame we want this point's acceleration defined in (N) + fixedframe : ReferenceFrame + The frame in which both points are fixed (B) + + Examples + ======== + + >>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> q = dynamicsymbols('q') + >>> qd = dynamicsymbols('q', 1) + >>> N = ReferenceFrame('N') + >>> B = N.orientnew('B', 'Axis', [q, N.z]) + >>> O = Point('O') + >>> P = O.locatenew('P', 10 * B.x) + >>> O.set_vel(N, 5 * N.x) + >>> P.a2pt_theory(O, N, B) + - 10*q'**2*B.x + 10*q''*B.y + + """ + + _check_frame(outframe) + _check_frame(fixedframe) + self._check_point(otherpoint) + dist = self.pos_from(otherpoint) + a = otherpoint.acc(outframe) + omega = fixedframe.ang_vel_in(outframe) + alpha = fixedframe.ang_acc_in(outframe) + self.set_acc(outframe, a + (alpha.cross(dist)) + + (omega.cross(omega.cross(dist)))) + return self.acc(outframe) + + def acc(self, frame): + """The acceleration Vector of this Point in a ReferenceFrame. + + Parameters + ========== + + frame : ReferenceFrame + The frame in which the returned acceleration vector will be defined + in. + + Examples + ======== + + >>> from sympy.physics.vector import Point, ReferenceFrame + >>> N = ReferenceFrame('N') + >>> p1 = Point('p1') + >>> p1.set_acc(N, 10 * N.x) + >>> p1.acc(N) + 10*N.x + + """ + + _check_frame(frame) + if not (frame in self._acc_dict): + if self.vel(frame) != 0: + return (self._vel_dict[frame]).dt(frame) + else: + return Vector(0) + return self._acc_dict[frame] + + def locatenew(self, name, value): + """Creates a new point with a position defined from this point. + + Parameters + ========== + + name : str + The name for the new point + value : Vector + The position of the new point relative to this point + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, Point + >>> N = ReferenceFrame('N') + >>> P1 = Point('P1') + >>> P2 = P1.locatenew('P2', 10 * N.x) + + """ + + if not isinstance(name, str): + raise TypeError('Must supply a valid name') + if value == 0: + value = Vector(0) + value = _check_vector(value) + p = Point(name) + p.set_pos(self, value) + self.set_pos(p, -value) + return p + + def pos_from(self, otherpoint): + """Returns a Vector distance between this Point and the other Point. + + Parameters + ========== + + otherpoint : Point + The otherpoint we are locating this one relative to + + Examples + ======== + + >>> from sympy.physics.vector import Point, ReferenceFrame + >>> N = ReferenceFrame('N') + >>> p1 = Point('p1') + >>> p2 = Point('p2') + >>> p1.set_pos(p2, 10 * N.x) + >>> p1.pos_from(p2) + 10*N.x + + """ + + outvec = Vector(0) + plist = self._pdict_list(otherpoint, 0) + for i in range(len(plist) - 1): + outvec += plist[i]._pos_dict[plist[i + 1]] + return outvec + + def set_acc(self, frame, value): + """Used to set the acceleration of this Point in a ReferenceFrame. + + Parameters + ========== + + frame : ReferenceFrame + The frame in which this point's acceleration is defined + value : Vector + The vector value of this point's acceleration in the frame + + Examples + ======== + + >>> from sympy.physics.vector import Point, ReferenceFrame + >>> N = ReferenceFrame('N') + >>> p1 = Point('p1') + >>> p1.set_acc(N, 10 * N.x) + >>> p1.acc(N) + 10*N.x + + """ + + if value == 0: + value = Vector(0) + value = _check_vector(value) + _check_frame(frame) + self._acc_dict.update({frame: value}) + + def set_pos(self, otherpoint, value): + """Used to set the position of this point w.r.t. another point. + + Parameters + ========== + + otherpoint : Point + The other point which this point's location is defined relative to + value : Vector + The vector which defines the location of this point + + Examples + ======== + + >>> from sympy.physics.vector import Point, ReferenceFrame + >>> N = ReferenceFrame('N') + >>> p1 = Point('p1') + >>> p2 = Point('p2') + >>> p1.set_pos(p2, 10 * N.x) + >>> p1.pos_from(p2) + 10*N.x + + """ + + if value == 0: + value = Vector(0) + value = _check_vector(value) + self._check_point(otherpoint) + self._pos_dict.update({otherpoint: value}) + otherpoint._pos_dict.update({self: -value}) + + def set_vel(self, frame, value): + """Sets the velocity Vector of this Point in a ReferenceFrame. + + Parameters + ========== + + frame : ReferenceFrame + The frame in which this point's velocity is defined + value : Vector + The vector value of this point's velocity in the frame + + Examples + ======== + + >>> from sympy.physics.vector import Point, ReferenceFrame + >>> N = ReferenceFrame('N') + >>> p1 = Point('p1') + >>> p1.set_vel(N, 10 * N.x) + >>> p1.vel(N) + 10*N.x + + """ + + if value == 0: + value = Vector(0) + value = _check_vector(value) + _check_frame(frame) + self._vel_dict.update({frame: value}) + + def v1pt_theory(self, otherpoint, outframe, interframe): + """Sets the velocity of this point with the 1-point theory. + + The 1-point theory for point velocity looks like this: + + ^N v^P = ^B v^P + ^N v^O + ^N omega^B x r^OP + + where O is a point fixed in B, P is a point moving in B, and B is + rotating in frame N. + + Parameters + ========== + + otherpoint : Point + The first point of the 1-point theory (O) + outframe : ReferenceFrame + The frame we want this point's velocity defined in (N) + interframe : ReferenceFrame + The intermediate frame in this calculation (B) + + Examples + ======== + + >>> from sympy.physics.vector import Point, ReferenceFrame + >>> from sympy.physics.vector import dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> q = dynamicsymbols('q') + >>> q2 = dynamicsymbols('q2') + >>> qd = dynamicsymbols('q', 1) + >>> q2d = dynamicsymbols('q2', 1) + >>> N = ReferenceFrame('N') + >>> B = ReferenceFrame('B') + >>> B.set_ang_vel(N, 5 * B.y) + >>> O = Point('O') + >>> P = O.locatenew('P', q * B.x + q2 * B.y) + >>> P.set_vel(B, qd * B.x + q2d * B.y) + >>> O.set_vel(N, 0) + >>> P.v1pt_theory(O, N, B) + q'*B.x + q2'*B.y - 5*q*B.z + + """ + + _check_frame(outframe) + _check_frame(interframe) + self._check_point(otherpoint) + dist = self.pos_from(otherpoint) + v1 = self.vel(interframe) + v2 = otherpoint.vel(outframe) + omega = interframe.ang_vel_in(outframe) + self.set_vel(outframe, v1 + v2 + (omega.cross(dist))) + return self.vel(outframe) + + def v2pt_theory(self, otherpoint, outframe, fixedframe): + """Sets the velocity of this point with the 2-point theory. + + The 2-point theory for point velocity looks like this: + + ^N v^P = ^N v^O + ^N omega^B x r^OP + + where O and P are both points fixed in frame B, which is rotating in + frame N. + + Parameters + ========== + + otherpoint : Point + The first point of the 2-point theory (O) + outframe : ReferenceFrame + The frame we want this point's velocity defined in (N) + fixedframe : ReferenceFrame + The frame in which both points are fixed (B) + + Examples + ======== + + >>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> q = dynamicsymbols('q') + >>> qd = dynamicsymbols('q', 1) + >>> N = ReferenceFrame('N') + >>> B = N.orientnew('B', 'Axis', [q, N.z]) + >>> O = Point('O') + >>> P = O.locatenew('P', 10 * B.x) + >>> O.set_vel(N, 5 * N.x) + >>> P.v2pt_theory(O, N, B) + 5*N.x + 10*q'*B.y + + """ + + _check_frame(outframe) + _check_frame(fixedframe) + self._check_point(otherpoint) + dist = self.pos_from(otherpoint) + v = otherpoint.vel(outframe) + omega = fixedframe.ang_vel_in(outframe) + self.set_vel(outframe, v + (omega.cross(dist))) + return self.vel(outframe) + + def vel(self, frame): + """The velocity Vector of this Point in the ReferenceFrame. + + Parameters + ========== + + frame : ReferenceFrame + The frame in which the returned velocity vector will be defined in + + Examples + ======== + + >>> from sympy.physics.vector import Point, ReferenceFrame, dynamicsymbols + >>> N = ReferenceFrame('N') + >>> p1 = Point('p1') + >>> p1.set_vel(N, 10 * N.x) + >>> p1.vel(N) + 10*N.x + + Velocities will be automatically calculated if possible, otherwise a + ``ValueError`` will be returned. If it is possible to calculate + multiple different velocities from the relative points, the points + defined most directly relative to this point will be used. In the case + of inconsistent relative positions of points, incorrect velocities may + be returned. It is up to the user to define prior relative positions + and velocities of points in a self-consistent way. + + >>> p = Point('p') + >>> q = dynamicsymbols('q') + >>> p.set_vel(N, 10 * N.x) + >>> p2 = Point('p2') + >>> p2.set_pos(p, q*N.x) + >>> p2.vel(N) + (Derivative(q(t), t) + 10)*N.x + + """ + + _check_frame(frame) + if not (frame in self._vel_dict): + valid_neighbor_found = False + is_cyclic = False + visited = [] + queue = [self] + candidate_neighbor = [] + while queue: # BFS to find nearest point + node = queue.pop(0) + if node not in visited: + visited.append(node) + for neighbor, neighbor_pos in node._pos_dict.items(): + if neighbor in visited: + continue + try: + # Checks if pos vector is valid + neighbor_pos.express(frame) + except ValueError: + continue + if neighbor in queue: + is_cyclic = True + try: + # Checks if point has its vel defined in req frame + neighbor_velocity = neighbor._vel_dict[frame] + except KeyError: + queue.append(neighbor) + continue + candidate_neighbor.append(neighbor) + if not valid_neighbor_found: + self.set_vel(frame, self.pos_from(neighbor).dt(frame) + neighbor_velocity) + valid_neighbor_found = True + if is_cyclic: + warn(filldedent(""" + Kinematic loops are defined among the positions of points. This + is likely not desired and may cause errors in your calculations. + """)) + if len(candidate_neighbor) > 1: + warn(filldedent(f""" + Velocity of {self.name} automatically calculated based on point + {candidate_neighbor[0].name} but it is also possible from + points(s): {str(candidate_neighbor[1:])}. Velocities from these + points are not necessarily the same. This may cause errors in + your calculations.""")) + if valid_neighbor_found: + return self._vel_dict[frame] + else: + raise ValueError(filldedent(f""" + Velocity of point {self.name} has not been defined in + ReferenceFrame {frame.name}.""")) + + return self._vel_dict[frame] + + def partial_velocity(self, frame, *gen_speeds): + """Returns the partial velocities of the linear velocity vector of this + point in the given frame with respect to one or more provided + generalized speeds. + + Parameters + ========== + frame : ReferenceFrame + The frame with which the velocity is defined in. + gen_speeds : functions of time + The generalized speeds. + + Returns + ======= + partial_velocities : tuple of Vector + The partial velocity vectors corresponding to the provided + generalized speeds. + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, Point + >>> from sympy.physics.vector import dynamicsymbols + >>> N = ReferenceFrame('N') + >>> A = ReferenceFrame('A') + >>> p = Point('p') + >>> u1, u2 = dynamicsymbols('u1, u2') + >>> p.set_vel(N, u1 * N.x + u2 * A.y) + >>> p.partial_velocity(N, u1) + N.x + >>> p.partial_velocity(N, u1, u2) + (N.x, A.y) + + """ + + from sympy.physics.vector.functions import partial_velocity + + vel = self.vel(frame) + partials = partial_velocity([vel], gen_speeds, frame)[0] + + if len(partials) == 1: + return partials[0] + else: + return tuple(partials) diff --git a/lib/python3.12/site-packages/sympy/physics/vector/printing.py b/lib/python3.12/site-packages/sympy/physics/vector/printing.py new file mode 100644 index 0000000000000000000000000000000000000000..2b589f673329e1e598b9b568fba6c07b8abe67bc --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/printing.py @@ -0,0 +1,371 @@ +from sympy.core.function import Derivative +from sympy.core.function import UndefinedFunction, AppliedUndef +from sympy.core.symbol import Symbol +from sympy.interactive.printing import init_printing +from sympy.printing.latex import LatexPrinter +from sympy.printing.pretty.pretty import PrettyPrinter +from sympy.printing.pretty.pretty_symbology import center_accent +from sympy.printing.str import StrPrinter +from sympy.printing.precedence import PRECEDENCE + +__all__ = ['vprint', 'vsstrrepr', 'vsprint', 'vpprint', 'vlatex', + 'init_vprinting'] + + +class VectorStrPrinter(StrPrinter): + """String Printer for vector expressions. """ + + def _print_Derivative(self, e): + from sympy.physics.vector.functions import dynamicsymbols + t = dynamicsymbols._t + if (bool(sum(i == t for i in e.variables)) & + isinstance(type(e.args[0]), UndefinedFunction)): + ol = str(e.args[0].func) + for i, v in enumerate(e.variables): + ol += dynamicsymbols._str + return ol + else: + return StrPrinter().doprint(e) + + def _print_Function(self, e): + from sympy.physics.vector.functions import dynamicsymbols + t = dynamicsymbols._t + if isinstance(type(e), UndefinedFunction): + return StrPrinter().doprint(e).replace("(%s)" % t, '') + return e.func.__name__ + "(%s)" % self.stringify(e.args, ", ") + + +class VectorStrReprPrinter(VectorStrPrinter): + """String repr printer for vector expressions.""" + def _print_str(self, s): + return repr(s) + + +class VectorLatexPrinter(LatexPrinter): + """Latex Printer for vector expressions. """ + + def _print_Function(self, expr, exp=None): + from sympy.physics.vector.functions import dynamicsymbols + func = expr.func.__name__ + t = dynamicsymbols._t + + if (hasattr(self, '_print_' + func) and not + isinstance(type(expr), UndefinedFunction)): + return getattr(self, '_print_' + func)(expr, exp) + elif isinstance(type(expr), UndefinedFunction) and (expr.args == (t,)): + # treat this function like a symbol + expr = Symbol(func) + if exp is not None: + # copied from LatexPrinter._helper_print_standard_power, which + # we can't call because we only have exp as a string. + base = self.parenthesize(expr, PRECEDENCE['Pow']) + base = self.parenthesize_super(base) + return r"%s^{%s}" % (base, exp) + else: + return super()._print(expr) + else: + return super()._print_Function(expr, exp) + + def _print_Derivative(self, der_expr): + from sympy.physics.vector.functions import dynamicsymbols + # make sure it is in the right form + der_expr = der_expr.doit() + if not isinstance(der_expr, Derivative): + return r"\left(%s\right)" % self.doprint(der_expr) + + # check if expr is a dynamicsymbol + t = dynamicsymbols._t + expr = der_expr.expr + red = expr.atoms(AppliedUndef) + syms = der_expr.variables + test1 = not all(True for i in red if i.free_symbols == {t}) + test2 = not all(t == i for i in syms) + if test1 or test2: + return super()._print_Derivative(der_expr) + + # done checking + dots = len(syms) + base = self._print_Function(expr) + base_split = base.split('_', 1) + base = base_split[0] + if dots == 1: + base = r"\dot{%s}" % base + elif dots == 2: + base = r"\ddot{%s}" % base + elif dots == 3: + base = r"\dddot{%s}" % base + elif dots == 4: + base = r"\ddddot{%s}" % base + else: # Fallback to standard printing + return super()._print_Derivative(der_expr) + if len(base_split) != 1: + base += '_' + base_split[1] + return base + + +class VectorPrettyPrinter(PrettyPrinter): + """Pretty Printer for vectorialexpressions. """ + + def _print_Derivative(self, deriv): + from sympy.physics.vector.functions import dynamicsymbols + # XXX use U('PARTIAL DIFFERENTIAL') here ? + t = dynamicsymbols._t + dot_i = 0 + syms = list(reversed(deriv.variables)) + + while len(syms) > 0: + if syms[-1] == t: + syms.pop() + dot_i += 1 + else: + return super()._print_Derivative(deriv) + + if not (isinstance(type(deriv.expr), UndefinedFunction) and + (deriv.expr.args == (t,))): + return super()._print_Derivative(deriv) + else: + pform = self._print_Function(deriv.expr) + + # the following condition would happen with some sort of non-standard + # dynamic symbol I guess, so we'll just print the SymPy way + if len(pform.picture) > 1: + return super()._print_Derivative(deriv) + + # There are only special symbols up to fourth-order derivatives + if dot_i >= 5: + return super()._print_Derivative(deriv) + + # Deal with special symbols + dots = {0: "", + 1: "\N{COMBINING DOT ABOVE}", + 2: "\N{COMBINING DIAERESIS}", + 3: "\N{COMBINING THREE DOTS ABOVE}", + 4: "\N{COMBINING FOUR DOTS ABOVE}"} + + d = pform.__dict__ + # if unicode is false then calculate number of apostrophes needed and + # add to output + if not self._use_unicode: + apostrophes = "" + for i in range(0, dot_i): + apostrophes += "'" + d['picture'][0] += apostrophes + "(t)" + else: + d['picture'] = [center_accent(d['picture'][0], dots[dot_i])] + return pform + + def _print_Function(self, e): + from sympy.physics.vector.functions import dynamicsymbols + t = dynamicsymbols._t + # XXX works only for applied functions + func = e.func + args = e.args + func_name = func.__name__ + pform = self._print_Symbol(Symbol(func_name)) + # If this function is an Undefined function of t, it is probably a + # dynamic symbol, so we'll skip the (t). The rest of the code is + # identical to the normal PrettyPrinter code + if not (isinstance(func, UndefinedFunction) and (args == (t,))): + return super()._print_Function(e) + return pform + + +def vprint(expr, **settings): + r"""Function for printing of expressions generated in the + sympy.physics vector package. + + Extends SymPy's StrPrinter, takes the same setting accepted by SymPy's + :func:`~.sstr`, and is equivalent to ``print(sstr(foo))``. + + Parameters + ========== + + expr : valid SymPy object + SymPy expression to print. + settings : args + Same as the settings accepted by SymPy's sstr(). + + Examples + ======== + + >>> from sympy.physics.vector import vprint, dynamicsymbols + >>> u1 = dynamicsymbols('u1') + >>> print(u1) + u1(t) + >>> vprint(u1) + u1 + + """ + + outstr = vsprint(expr, **settings) + + import builtins + if (outstr != 'None'): + builtins._ = outstr + print(outstr) + + +def vsstrrepr(expr, **settings): + """Function for displaying expression representation's with vector + printing enabled. + + Parameters + ========== + + expr : valid SymPy object + SymPy expression to print. + settings : args + Same as the settings accepted by SymPy's sstrrepr(). + + """ + p = VectorStrReprPrinter(settings) + return p.doprint(expr) + + +def vsprint(expr, **settings): + r"""Function for displaying expressions generated in the + sympy.physics vector package. + + Returns the output of vprint() as a string. + + Parameters + ========== + + expr : valid SymPy object + SymPy expression to print + settings : args + Same as the settings accepted by SymPy's sstr(). + + Examples + ======== + + >>> from sympy.physics.vector import vsprint, dynamicsymbols + >>> u1, u2 = dynamicsymbols('u1 u2') + >>> u2d = dynamicsymbols('u2', level=1) + >>> print("%s = %s" % (u1, u2 + u2d)) + u1(t) = u2(t) + Derivative(u2(t), t) + >>> print("%s = %s" % (vsprint(u1), vsprint(u2 + u2d))) + u1 = u2 + u2' + + """ + + string_printer = VectorStrPrinter(settings) + return string_printer.doprint(expr) + + +def vpprint(expr, **settings): + r"""Function for pretty printing of expressions generated in the + sympy.physics vector package. + + Mainly used for expressions not inside a vector; the output of running + scripts and generating equations of motion. Takes the same options as + SymPy's :func:`~.pretty_print`; see that function for more information. + + Parameters + ========== + + expr : valid SymPy object + SymPy expression to pretty print + settings : args + Same as those accepted by SymPy's pretty_print. + + + """ + + pp = VectorPrettyPrinter(settings) + + # Note that this is copied from sympy.printing.pretty.pretty_print: + + # XXX: this is an ugly hack, but at least it works + use_unicode = pp._settings['use_unicode'] + from sympy.printing.pretty.pretty_symbology import pretty_use_unicode + uflag = pretty_use_unicode(use_unicode) + + try: + return pp.doprint(expr) + finally: + pretty_use_unicode(uflag) + + +def vlatex(expr, **settings): + r"""Function for printing latex representation of sympy.physics.vector + objects. + + For latex representation of Vectors, Dyadics, and dynamicsymbols. Takes the + same options as SymPy's :func:`~.latex`; see that function for more + information; + + Parameters + ========== + + expr : valid SymPy object + SymPy expression to represent in LaTeX form + settings : args + Same as latex() + + Examples + ======== + + >>> from sympy.physics.vector import vlatex, ReferenceFrame, dynamicsymbols + >>> N = ReferenceFrame('N') + >>> q1, q2 = dynamicsymbols('q1 q2') + >>> q1d, q2d = dynamicsymbols('q1 q2', 1) + >>> q1dd, q2dd = dynamicsymbols('q1 q2', 2) + >>> vlatex(N.x + N.y) + '\\mathbf{\\hat{n}_x} + \\mathbf{\\hat{n}_y}' + >>> vlatex(q1 + q2) + 'q_{1} + q_{2}' + >>> vlatex(q1d) + '\\dot{q}_{1}' + >>> vlatex(q1 * q2d) + 'q_{1} \\dot{q}_{2}' + >>> vlatex(q1dd * q1 / q1d) + '\\frac{q_{1} \\ddot{q}_{1}}{\\dot{q}_{1}}' + + """ + latex_printer = VectorLatexPrinter(settings) + + return latex_printer.doprint(expr) + + +def init_vprinting(**kwargs): + """Initializes time derivative printing for all SymPy objects, i.e. any + functions of time will be displayed in a more compact notation. The main + benefit of this is for printing of time derivatives; instead of + displaying as ``Derivative(f(t),t)``, it will display ``f'``. This is + only actually needed for when derivatives are present and are not in a + physics.vector.Vector or physics.vector.Dyadic object. This function is a + light wrapper to :func:`~.init_printing`. Any keyword + arguments for it are valid here. + + {0} + + Examples + ======== + + >>> from sympy import Function, symbols + >>> t, x = symbols('t, x') + >>> omega = Function('omega') + >>> omega(x).diff() + Derivative(omega(x), x) + >>> omega(t).diff() + Derivative(omega(t), t) + + Now use the string printer: + + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> omega(x).diff() + Derivative(omega(x), x) + >>> omega(t).diff() + omega' + + """ + kwargs['str_printer'] = vsstrrepr + kwargs['pretty_printer'] = vpprint + kwargs['latex_printer'] = vlatex + init_printing(**kwargs) + + +params = init_printing.__doc__.split('Examples\n ========')[0] # type: ignore +init_vprinting.__doc__ = init_vprinting.__doc__.format(params) # type: ignore diff --git a/lib/python3.12/site-packages/sympy/physics/vector/tests/__init__.py b/lib/python3.12/site-packages/sympy/physics/vector/tests/__init__.py new file mode 100644 index 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b/lib/python3.12/site-packages/sympy/physics/vector/tests/__pycache__/test_vector.cpython-312.pyc new file mode 100644 index 0000000000000000000000000000000000000000..238cabb5d583047c8d38acda99fd3d46d7cd3915 Binary files /dev/null and b/lib/python3.12/site-packages/sympy/physics/vector/tests/__pycache__/test_vector.cpython-312.pyc differ diff --git a/lib/python3.12/site-packages/sympy/physics/vector/tests/test_dyadic.py b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_dyadic.py new file mode 100644 index 0000000000000000000000000000000000000000..ab365b4687162ccbd3b21dd9709b84dbcdec8aa0 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_dyadic.py @@ -0,0 +1,123 @@ +from sympy.core.numbers import (Float, pi) +from sympy.core.symbol import symbols +from sympy.functions.elementary.trigonometric import (cos, sin) +from sympy.matrices.immutable import ImmutableDenseMatrix as Matrix +from sympy.physics.vector import ReferenceFrame, dynamicsymbols, outer +from sympy.physics.vector.dyadic import _check_dyadic +from sympy.testing.pytest import raises + +A = ReferenceFrame('A') + + +def test_dyadic(): + d1 = A.x | A.x + d2 = A.y | A.y + d3 = A.x | A.y + assert d1 * 0 == 0 + assert d1 != 0 + assert d1 * 2 == 2 * A.x | A.x + assert d1 / 2. == 0.5 * d1 + assert d1 & (0 * d1) == 0 + assert d1 & d2 == 0 + assert d1 & A.x == A.x + assert d1 ^ A.x == 0 + assert d1 ^ A.y == A.x | A.z + assert d1 ^ A.z == - A.x | A.y + assert d2 ^ A.x == - A.y | A.z + assert A.x ^ d1 == 0 + assert A.y ^ d1 == - A.z | A.x + assert A.z ^ d1 == A.y | A.x + assert A.x & d1 == A.x + assert A.y & d1 == 0 + assert A.y & d2 == A.y + assert d1 & d3 == A.x | A.y + assert d3 & d1 == 0 + assert d1.dt(A) == 0 + q = dynamicsymbols('q') + qd = dynamicsymbols('q', 1) + B = A.orientnew('B', 'Axis', [q, A.z]) + assert d1.express(B) == d1.express(B, B) + assert d1.express(B) == ((cos(q)**2) * (B.x | B.x) + (-sin(q) * cos(q)) * + (B.x | B.y) + (-sin(q) * cos(q)) * (B.y | B.x) + (sin(q)**2) * + (B.y | B.y)) + assert d1.express(B, A) == (cos(q)) * (B.x | A.x) + (-sin(q)) * (B.y | A.x) + assert d1.express(A, B) == (cos(q)) * (A.x | B.x) + (-sin(q)) * (A.x | B.y) + assert d1.dt(B) == (-qd) * (A.y | A.x) + (-qd) * (A.x | A.y) + + assert d1.to_matrix(A) == Matrix([[1, 0, 0], [0, 0, 0], [0, 0, 0]]) + assert d1.to_matrix(A, B) == Matrix([[cos(q), -sin(q), 0], + [0, 0, 0], + [0, 0, 0]]) + assert d3.to_matrix(A) == Matrix([[0, 1, 0], [0, 0, 0], [0, 0, 0]]) + a, b, c, d, e, f = symbols('a, b, c, d, e, f') + v1 = a * A.x + b * A.y + c * A.z + v2 = d * A.x + e * A.y + f * A.z + d4 = v1.outer(v2) + assert d4.to_matrix(A) == Matrix([[a * d, a * e, a * f], + [b * d, b * e, b * f], + [c * d, c * e, c * f]]) + d5 = v1.outer(v1) + C = A.orientnew('C', 'Axis', [q, A.x]) + for expected, actual in zip(C.dcm(A) * d5.to_matrix(A) * C.dcm(A).T, + d5.to_matrix(C)): + assert (expected - actual).simplify() == 0 + + raises(TypeError, lambda: d1.applyfunc(0)) + + +def test_dyadic_simplify(): + x, y, z, k, n, m, w, f, s, A = symbols('x, y, z, k, n, m, w, f, s, A') + N = ReferenceFrame('N') + + dy = N.x | N.x + test1 = (1 / x + 1 / y) * dy + assert (N.x & test1 & N.x) != (x + y) / (x * y) + test1 = test1.simplify() + assert (N.x & test1 & N.x) == (x + y) / (x * y) + + test2 = (A**2 * s**4 / (4 * pi * k * m**3)) * dy + test2 = test2.simplify() + assert (N.x & test2 & N.x) == (A**2 * s**4 / (4 * pi * k * m**3)) + + test3 = ((4 + 4 * x - 2 * (2 + 2 * x)) / (2 + 2 * x)) * dy + test3 = test3.simplify() + assert (N.x & test3 & N.x) == 0 + + test4 = ((-4 * x * y**2 - 2 * y**3 - 2 * x**2 * y) / (x + y)**2) * dy + test4 = test4.simplify() + assert (N.x & test4 & N.x) == -2 * y + + +def test_dyadic_subs(): + N = ReferenceFrame('N') + s = symbols('s') + a = s*(N.x | N.x) + assert a.subs({s: 2}) == 2*(N.x | N.x) + + +def test_check_dyadic(): + raises(TypeError, lambda: _check_dyadic(0)) + + +def test_dyadic_evalf(): + N = ReferenceFrame('N') + a = pi * (N.x | N.x) + assert a.evalf(3) == Float('3.1416', 3) * (N.x | N.x) + s = symbols('s') + a = 5 * s * pi* (N.x | N.x) + assert a.evalf(2) == Float('5', 2) * Float('3.1416', 2) * s * (N.x | N.x) + assert a.evalf(9, subs={s: 5.124}) == Float('80.48760378', 9) * (N.x | N.x) + + +def test_dyadic_xreplace(): + x, y, z = symbols('x y z') + N = ReferenceFrame('N') + D = outer(N.x, N.x) + v = x*y * D + assert v.xreplace({x : cos(x)}) == cos(x)*y * D + assert v.xreplace({x*y : pi}) == pi * D + v = (x*y)**z * D + assert v.xreplace({(x*y)**z : 1}) == D + assert v.xreplace({x:1, z:0}) == D + raises(TypeError, lambda: v.xreplace()) + raises(TypeError, lambda: v.xreplace([x, y])) diff --git a/lib/python3.12/site-packages/sympy/physics/vector/tests/test_fieldfunctions.py b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_fieldfunctions.py new file mode 100644 index 0000000000000000000000000000000000000000..4e5c67aad44ca972dac6e455c57b60a74bae207a --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_fieldfunctions.py @@ -0,0 +1,133 @@ +from sympy.core.singleton import S +from sympy.core.symbol import Symbol +from sympy.functions.elementary.trigonometric import (cos, sin) +from sympy.physics.vector import ReferenceFrame, Vector, Point, \ + dynamicsymbols +from sympy.physics.vector.fieldfunctions import divergence, \ + gradient, curl, is_conservative, is_solenoidal, \ + scalar_potential, scalar_potential_difference +from sympy.testing.pytest import raises + +R = ReferenceFrame('R') +q = dynamicsymbols('q') +P = R.orientnew('P', 'Axis', [q, R.z]) + + +def test_curl(): + assert curl(Vector(0), R) == Vector(0) + assert curl(R.x, R) == Vector(0) + assert curl(2*R[1]**2*R.y, R) == Vector(0) + assert curl(R[0]*R[1]*R.z, R) == R[0]*R.x - R[1]*R.y + assert curl(R[0]*R[1]*R[2] * (R.x+R.y+R.z), R) == \ + (-R[0]*R[1] + R[0]*R[2])*R.x + (R[0]*R[1] - R[1]*R[2])*R.y + \ + (-R[0]*R[2] + R[1]*R[2])*R.z + assert curl(2*R[0]**2*R.y, R) == 4*R[0]*R.z + assert curl(P[0]**2*R.x + P.y, R) == \ + - 2*(R[0]*cos(q) + R[1]*sin(q))*sin(q)*R.z + assert curl(P[0]*R.y, P) == cos(q)*P.z + + +def test_divergence(): + assert divergence(Vector(0), R) is S.Zero + assert divergence(R.x, R) is S.Zero + assert divergence(R[0]**2*R.x, R) == 2*R[0] + assert divergence(R[0]*R[1]*R[2] * (R.x+R.y+R.z), R) == \ + R[0]*R[1] + R[0]*R[2] + R[1]*R[2] + assert divergence((1/(R[0]*R[1]*R[2])) * (R.x+R.y+R.z), R) == \ + -1/(R[0]*R[1]*R[2]**2) - 1/(R[0]*R[1]**2*R[2]) - \ + 1/(R[0]**2*R[1]*R[2]) + v = P[0]*P.x + P[1]*P.y + P[2]*P.z + assert divergence(v, P) == 3 + assert divergence(v, R).simplify() == 3 + assert divergence(P[0]*R.x + R[0]*P.x, R) == 2*cos(q) + + +def test_gradient(): + a = Symbol('a') + assert gradient(0, R) == Vector(0) + assert gradient(R[0], R) == R.x + assert gradient(R[0]*R[1]*R[2], R) == \ + R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z + assert gradient(2*R[0]**2, R) == 4*R[0]*R.x + assert gradient(a*sin(R[1])/R[0], R) == \ + - a*sin(R[1])/R[0]**2*R.x + a*cos(R[1])/R[0]*R.y + assert gradient(P[0]*P[1], R) == \ + ((-R[0]*sin(q) + R[1]*cos(q))*cos(q) - (R[0]*cos(q) + R[1]*sin(q))*sin(q))*R.x + \ + ((-R[0]*sin(q) + R[1]*cos(q))*sin(q) + (R[0]*cos(q) + R[1]*sin(q))*cos(q))*R.y + assert gradient(P[0]*R[2], P) == P[2]*P.x + P[0]*P.z + + +scalar_field = 2*R[0]**2*R[1]*R[2] +grad_field = gradient(scalar_field, R) +vector_field = R[1]**2*R.x + 3*R[0]*R.y + 5*R[1]*R[2]*R.z +curl_field = curl(vector_field, R) + + +def test_conservative(): + assert is_conservative(0) is True + assert is_conservative(R.x) is True + assert is_conservative(2 * R.x + 3 * R.y + 4 * R.z) is True + assert is_conservative(R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z) is \ + True + assert is_conservative(R[0] * R.y) is False + assert is_conservative(grad_field) is True + assert is_conservative(curl_field) is False + assert is_conservative(4*R[0]*R[1]*R[2]*R.x + 2*R[0]**2*R[2]*R.y) is \ + False + assert is_conservative(R[2]*P.x + P[0]*R.z) is True + + +def test_solenoidal(): + assert is_solenoidal(0) is True + assert is_solenoidal(R.x) is True + assert is_solenoidal(2 * R.x + 3 * R.y + 4 * R.z) is True + assert is_solenoidal(R[1]*R[2]*R.x + R[0]*R[2]*R.y + R[0]*R[1]*R.z) is \ + True + assert is_solenoidal(R[1] * R.y) is False + assert is_solenoidal(grad_field) is False + assert is_solenoidal(curl_field) is True + assert is_solenoidal((-2*R[1] + 3)*R.z) is True + assert is_solenoidal(cos(q)*R.x + sin(q)*R.y + cos(q)*P.z) is True + assert is_solenoidal(R[2]*P.x + P[0]*R.z) is True + + +def test_scalar_potential(): + assert scalar_potential(0, R) == 0 + assert scalar_potential(R.x, R) == R[0] + assert scalar_potential(R.y, R) == R[1] + assert scalar_potential(R.z, R) == R[2] + assert scalar_potential(R[1]*R[2]*R.x + R[0]*R[2]*R.y + \ + R[0]*R[1]*R.z, R) == R[0]*R[1]*R[2] + assert scalar_potential(grad_field, R) == scalar_field + assert scalar_potential(R[2]*P.x + P[0]*R.z, R) == \ + R[0]*R[2]*cos(q) + R[1]*R[2]*sin(q) + assert scalar_potential(R[2]*P.x + P[0]*R.z, P) == P[0]*P[2] + raises(ValueError, lambda: scalar_potential(R[0] * R.y, R)) + + +def test_scalar_potential_difference(): + origin = Point('O') + point1 = origin.locatenew('P1', 1*R.x + 2*R.y + 3*R.z) + point2 = origin.locatenew('P2', 4*R.x + 5*R.y + 6*R.z) + genericpointR = origin.locatenew('RP', R[0]*R.x + R[1]*R.y + R[2]*R.z) + genericpointP = origin.locatenew('PP', P[0]*P.x + P[1]*P.y + P[2]*P.z) + assert scalar_potential_difference(S.Zero, R, point1, point2, \ + origin) == 0 + assert scalar_potential_difference(scalar_field, R, origin, \ + genericpointR, origin) == \ + scalar_field + assert scalar_potential_difference(grad_field, R, origin, \ + genericpointR, origin) == \ + scalar_field + assert scalar_potential_difference(grad_field, R, point1, point2, + origin) == 948 + assert scalar_potential_difference(R[1]*R[2]*R.x + R[0]*R[2]*R.y + \ + R[0]*R[1]*R.z, R, point1, + genericpointR, origin) == \ + R[0]*R[1]*R[2] - 6 + potential_diff_P = 2*P[2]*(P[0]*sin(q) + P[1]*cos(q))*\ + (P[0]*cos(q) - P[1]*sin(q))**2 + assert scalar_potential_difference(grad_field, P, origin, \ + genericpointP, \ + origin).simplify() == \ + potential_diff_P diff --git a/lib/python3.12/site-packages/sympy/physics/vector/tests/test_frame.py b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_frame.py new file mode 100644 index 0000000000000000000000000000000000000000..8e2d0234c7d2d9f91fdb5421c5a92f05495006c6 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_frame.py @@ -0,0 +1,761 @@ +from sympy.core.numbers import pi +from sympy.core.symbol import symbols +from sympy.simplify import trigsimp +from sympy.functions.elementary.trigonometric import (cos, sin) +from sympy.matrices.dense import (eye, zeros) +from sympy.matrices.immutable import ImmutableDenseMatrix as Matrix +from sympy.simplify.simplify import simplify +from sympy.physics.vector import (ReferenceFrame, Vector, CoordinateSym, + dynamicsymbols, time_derivative, express, + dot) +from sympy.physics.vector.frame import _check_frame +from sympy.physics.vector.vector import VectorTypeError +from sympy.testing.pytest import raises +import warnings +import pickle + + +def test_dict_list(): + + A = ReferenceFrame('A') + B = ReferenceFrame('B') + C = ReferenceFrame('C') + D = ReferenceFrame('D') + E = ReferenceFrame('E') + F = ReferenceFrame('F') + + B.orient_axis(A, A.x, 1.0) + C.orient_axis(B, B.x, 1.0) + D.orient_axis(C, C.x, 1.0) + + assert D._dict_list(A, 0) == [D, C, B, A] + + E.orient_axis(D, D.x, 1.0) + + assert C._dict_list(A, 0) == [C, B, A] + assert C._dict_list(E, 0) == [C, D, E] + + # only 0, 1, 2 permitted for second argument + raises(ValueError, lambda: C._dict_list(E, 5)) + # no connecting path + raises(ValueError, lambda: F._dict_list(A, 0)) + + +def test_coordinate_vars(): + """Tests the coordinate variables functionality""" + A = ReferenceFrame('A') + assert CoordinateSym('Ax', A, 0) == A[0] + assert CoordinateSym('Ax', A, 1) == A[1] + assert CoordinateSym('Ax', A, 2) == A[2] + raises(ValueError, lambda: CoordinateSym('Ax', A, 3)) + q = dynamicsymbols('q') + qd = dynamicsymbols('q', 1) + assert isinstance(A[0], CoordinateSym) and \ + isinstance(A[0], CoordinateSym) and \ + isinstance(A[0], CoordinateSym) + assert A.variable_map(A) == {A[0]:A[0], A[1]:A[1], A[2]:A[2]} + assert A[0].frame == A + B = A.orientnew('B', 'Axis', [q, A.z]) + assert B.variable_map(A) == {B[2]: A[2], B[1]: -A[0]*sin(q) + A[1]*cos(q), + B[0]: A[0]*cos(q) + A[1]*sin(q)} + assert A.variable_map(B) == {A[0]: B[0]*cos(q) - B[1]*sin(q), + A[1]: B[0]*sin(q) + B[1]*cos(q), A[2]: B[2]} + assert time_derivative(B[0], A) == -A[0]*sin(q)*qd + A[1]*cos(q)*qd + assert time_derivative(B[1], A) == -A[0]*cos(q)*qd - A[1]*sin(q)*qd + assert time_derivative(B[2], A) == 0 + assert express(B[0], A, variables=True) == A[0]*cos(q) + A[1]*sin(q) + assert express(B[1], A, variables=True) == -A[0]*sin(q) + A[1]*cos(q) + assert express(B[2], A, variables=True) == A[2] + assert time_derivative(A[0]*A.x + A[1]*A.y + A[2]*A.z, B) == A[1]*qd*A.x - A[0]*qd*A.y + assert time_derivative(B[0]*B.x + B[1]*B.y + B[2]*B.z, A) == - B[1]*qd*B.x + B[0]*qd*B.y + assert express(B[0]*B[1]*B[2], A, variables=True) == \ + A[2]*(-A[0]*sin(q) + A[1]*cos(q))*(A[0]*cos(q) + A[1]*sin(q)) + assert (time_derivative(B[0]*B[1]*B[2], A) - + (A[2]*(-A[0]**2*cos(2*q) - + 2*A[0]*A[1]*sin(2*q) + + A[1]**2*cos(2*q))*qd)).trigsimp() == 0 + assert express(B[0]*B.x + B[1]*B.y + B[2]*B.z, A) == \ + (B[0]*cos(q) - B[1]*sin(q))*A.x + (B[0]*sin(q) + \ + B[1]*cos(q))*A.y + B[2]*A.z + assert express(B[0]*B.x + B[1]*B.y + B[2]*B.z, A, + variables=True).simplify() == A[0]*A.x + A[1]*A.y + A[2]*A.z + assert express(A[0]*A.x + A[1]*A.y + A[2]*A.z, B) == \ + (A[0]*cos(q) + A[1]*sin(q))*B.x + \ + (-A[0]*sin(q) + A[1]*cos(q))*B.y + A[2]*B.z + assert express(A[0]*A.x + A[1]*A.y + A[2]*A.z, B, + variables=True).simplify() == B[0]*B.x + B[1]*B.y + B[2]*B.z + N = B.orientnew('N', 'Axis', [-q, B.z]) + assert ({k: v.simplify() for k, v in N.variable_map(A).items()} == + {N[0]: A[0], N[2]: A[2], N[1]: A[1]}) + C = A.orientnew('C', 'Axis', [q, A.x + A.y + A.z]) + mapping = A.variable_map(C) + assert trigsimp(mapping[A[0]]) == (2*C[0]*cos(q)/3 + C[0]/3 - + 2*C[1]*sin(q + pi/6)/3 + + C[1]/3 - 2*C[2]*cos(q + pi/3)/3 + + C[2]/3) + assert trigsimp(mapping[A[1]]) == -2*C[0]*cos(q + pi/3)/3 + \ + C[0]/3 + 2*C[1]*cos(q)/3 + C[1]/3 - 2*C[2]*sin(q + pi/6)/3 + C[2]/3 + assert trigsimp(mapping[A[2]]) == -2*C[0]*sin(q + pi/6)/3 + C[0]/3 - \ + 2*C[1]*cos(q + pi/3)/3 + C[1]/3 + 2*C[2]*cos(q)/3 + C[2]/3 + + +def test_ang_vel(): + q1, q2, q3, q4 = dynamicsymbols('q1 q2 q3 q4') + q1d, q2d, q3d, q4d = dynamicsymbols('q1 q2 q3 q4', 1) + N = ReferenceFrame('N') + A = N.orientnew('A', 'Axis', [q1, N.z]) + B = A.orientnew('B', 'Axis', [q2, A.x]) + C = B.orientnew('C', 'Axis', [q3, B.y]) + D = N.orientnew('D', 'Axis', [q4, N.y]) + u1, u2, u3 = dynamicsymbols('u1 u2 u3') + assert A.ang_vel_in(N) == (q1d)*A.z + assert B.ang_vel_in(N) == (q2d)*B.x + (q1d)*A.z + assert C.ang_vel_in(N) == (q3d)*C.y + (q2d)*B.x + (q1d)*A.z + + A2 = N.orientnew('A2', 'Axis', [q4, N.y]) + assert N.ang_vel_in(N) == 0 + assert N.ang_vel_in(A) == -q1d*N.z + assert N.ang_vel_in(B) == -q1d*A.z - q2d*B.x + assert N.ang_vel_in(C) == -q1d*A.z - q2d*B.x - q3d*B.y + assert N.ang_vel_in(A2) == -q4d*N.y + + assert A.ang_vel_in(N) == q1d*N.z + assert A.ang_vel_in(A) == 0 + assert A.ang_vel_in(B) == - q2d*B.x + assert A.ang_vel_in(C) == - q2d*B.x - q3d*B.y + assert A.ang_vel_in(A2) == q1d*N.z - q4d*N.y + + assert B.ang_vel_in(N) == q1d*A.z + q2d*A.x + assert B.ang_vel_in(A) == q2d*A.x + assert B.ang_vel_in(B) == 0 + assert B.ang_vel_in(C) == -q3d*B.y + assert B.ang_vel_in(A2) == q1d*A.z + q2d*A.x - q4d*N.y + + assert C.ang_vel_in(N) == q1d*A.z + q2d*A.x + q3d*B.y + assert C.ang_vel_in(A) == q2d*A.x + q3d*C.y + assert C.ang_vel_in(B) == q3d*B.y + assert C.ang_vel_in(C) == 0 + assert C.ang_vel_in(A2) == q1d*A.z + q2d*A.x + q3d*B.y - q4d*N.y + + assert A2.ang_vel_in(N) == q4d*A2.y + assert A2.ang_vel_in(A) == q4d*A2.y - q1d*N.z + assert A2.ang_vel_in(B) == q4d*N.y - q1d*A.z - q2d*A.x + assert A2.ang_vel_in(C) == q4d*N.y - q1d*A.z - q2d*A.x - q3d*B.y + assert A2.ang_vel_in(A2) == 0 + + C.set_ang_vel(N, u1*C.x + u2*C.y + u3*C.z) + assert C.ang_vel_in(N) == (u1)*C.x + (u2)*C.y + (u3)*C.z + assert N.ang_vel_in(C) == (-u1)*C.x + (-u2)*C.y + (-u3)*C.z + assert C.ang_vel_in(D) == (u1)*C.x + (u2)*C.y + (u3)*C.z + (-q4d)*D.y + assert D.ang_vel_in(C) == (-u1)*C.x + (-u2)*C.y + (-u3)*C.z + (q4d)*D.y + + q0 = dynamicsymbols('q0') + q0d = dynamicsymbols('q0', 1) + E = N.orientnew('E', 'Quaternion', (q0, q1, q2, q3)) + assert E.ang_vel_in(N) == ( + 2 * (q1d * q0 + q2d * q3 - q3d * q2 - q0d * q1) * E.x + + 2 * (q2d * q0 + q3d * q1 - q1d * q3 - q0d * q2) * E.y + + 2 * (q3d * q0 + q1d * q2 - q2d * q1 - q0d * q3) * E.z) + + F = N.orientnew('F', 'Body', (q1, q2, q3), 313) + assert F.ang_vel_in(N) == ((sin(q2)*sin(q3)*q1d + cos(q3)*q2d)*F.x + + (sin(q2)*cos(q3)*q1d - sin(q3)*q2d)*F.y + (cos(q2)*q1d + q3d)*F.z) + G = N.orientnew('G', 'Axis', (q1, N.x + N.y)) + assert G.ang_vel_in(N) == q1d * (N.x + N.y).normalize() + assert N.ang_vel_in(G) == -q1d * (N.x + N.y).normalize() + + +def test_dcm(): + q1, q2, q3, q4 = dynamicsymbols('q1 q2 q3 q4') + N = ReferenceFrame('N') + A = N.orientnew('A', 'Axis', [q1, N.z]) + B = A.orientnew('B', 'Axis', [q2, A.x]) + C = B.orientnew('C', 'Axis', [q3, B.y]) + D = N.orientnew('D', 'Axis', [q4, N.y]) + E = N.orientnew('E', 'Space', [q1, q2, q3], '123') + assert N.dcm(C) == Matrix([ + [- sin(q1) * sin(q2) * sin(q3) + cos(q1) * cos(q3), - sin(q1) * + cos(q2), sin(q1) * sin(q2) * cos(q3) + sin(q3) * cos(q1)], [sin(q1) * + cos(q3) + sin(q2) * sin(q3) * cos(q1), cos(q1) * cos(q2), sin(q1) * + sin(q3) - sin(q2) * cos(q1) * cos(q3)], [- sin(q3) * cos(q2), sin(q2), + cos(q2) * cos(q3)]]) + # This is a little touchy. Is it ok to use simplify in assert? + test_mat = D.dcm(C) - Matrix( + [[cos(q1) * cos(q3) * cos(q4) - sin(q3) * (- sin(q4) * cos(q2) + + sin(q1) * sin(q2) * cos(q4)), - sin(q2) * sin(q4) - sin(q1) * + cos(q2) * cos(q4), sin(q3) * cos(q1) * cos(q4) + cos(q3) * (- sin(q4) * + cos(q2) + sin(q1) * sin(q2) * cos(q4))], [sin(q1) * cos(q3) + + sin(q2) * sin(q3) * cos(q1), cos(q1) * cos(q2), sin(q1) * sin(q3) - + sin(q2) * cos(q1) * cos(q3)], [sin(q4) * cos(q1) * cos(q3) - + sin(q3) * (cos(q2) * cos(q4) + sin(q1) * sin(q2) * sin(q4)), sin(q2) * + cos(q4) - sin(q1) * sin(q4) * cos(q2), sin(q3) * sin(q4) * cos(q1) + + cos(q3) * (cos(q2) * cos(q4) + sin(q1) * sin(q2) * sin(q4))]]) + assert test_mat.expand() == zeros(3, 3) + assert E.dcm(N) == Matrix( + [[cos(q2)*cos(q3), sin(q3)*cos(q2), -sin(q2)], + [sin(q1)*sin(q2)*cos(q3) - sin(q3)*cos(q1), sin(q1)*sin(q2)*sin(q3) + + cos(q1)*cos(q3), sin(q1)*cos(q2)], [sin(q1)*sin(q3) + + sin(q2)*cos(q1)*cos(q3), - sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1), + cos(q1)*cos(q2)]]) + +def test_w_diff_dcm1(): + # Ref: + # Dynamics Theory and Applications, Kane 1985 + # Sec. 2.1 ANGULAR VELOCITY + A = ReferenceFrame('A') + B = ReferenceFrame('B') + + c11, c12, c13 = dynamicsymbols('C11 C12 C13') + c21, c22, c23 = dynamicsymbols('C21 C22 C23') + c31, c32, c33 = dynamicsymbols('C31 C32 C33') + + c11d, c12d, c13d = dynamicsymbols('C11 C12 C13', level=1) + c21d, c22d, c23d = dynamicsymbols('C21 C22 C23', level=1) + c31d, c32d, c33d = dynamicsymbols('C31 C32 C33', level=1) + + DCM = Matrix([ + [c11, c12, c13], + [c21, c22, c23], + [c31, c32, c33] + ]) + + B.orient(A, 'DCM', DCM) + b1a = (B.x).express(A) + b2a = (B.y).express(A) + b3a = (B.z).express(A) + + # Equation (2.1.1) + B.set_ang_vel(A, B.x*(dot((b3a).dt(A), B.y)) + + B.y*(dot((b1a).dt(A), B.z)) + + B.z*(dot((b2a).dt(A), B.x))) + + # Equation (2.1.21) + expr = ( (c12*c13d + c22*c23d + c32*c33d)*B.x + + (c13*c11d + c23*c21d + c33*c31d)*B.y + + (c11*c12d + c21*c22d + c31*c32d)*B.z) + assert B.ang_vel_in(A) - expr == 0 + +def test_w_diff_dcm2(): + q1, q2, q3 = dynamicsymbols('q1:4') + N = ReferenceFrame('N') + A = N.orientnew('A', 'axis', [q1, N.x]) + B = A.orientnew('B', 'axis', [q2, A.y]) + C = B.orientnew('C', 'axis', [q3, B.z]) + + DCM = C.dcm(N).T + D = N.orientnew('D', 'DCM', DCM) + + # Frames D and C are the same ReferenceFrame, + # since they have equal DCM respect to frame N. + # Therefore, D and C should have same angle velocity in N. + assert D.dcm(N) == C.dcm(N) == Matrix([ + [cos(q2)*cos(q3), sin(q1)*sin(q2)*cos(q3) + + sin(q3)*cos(q1), sin(q1)*sin(q3) - + sin(q2)*cos(q1)*cos(q3)], [-sin(q3)*cos(q2), + -sin(q1)*sin(q2)*sin(q3) + cos(q1)*cos(q3), + sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1)], + [sin(q2), -sin(q1)*cos(q2), cos(q1)*cos(q2)]]) + assert (D.ang_vel_in(N) - C.ang_vel_in(N)).express(N).simplify() == 0 + +def test_orientnew_respects_parent_class(): + class MyReferenceFrame(ReferenceFrame): + pass + B = MyReferenceFrame('B') + C = B.orientnew('C', 'Axis', [0, B.x]) + assert isinstance(C, MyReferenceFrame) + + +def test_orientnew_respects_input_indices(): + N = ReferenceFrame('N') + q1 = dynamicsymbols('q1') + A = N.orientnew('a', 'Axis', [q1, N.z]) + #modify default indices: + minds = [x+'1' for x in N.indices] + B = N.orientnew('b', 'Axis', [q1, N.z], indices=minds) + + assert N.indices == A.indices + assert B.indices == minds + +def test_orientnew_respects_input_latexs(): + N = ReferenceFrame('N') + q1 = dynamicsymbols('q1') + A = N.orientnew('a', 'Axis', [q1, N.z]) + + #build default and alternate latex_vecs: + def_latex_vecs = [(r"\mathbf{\hat{%s}_%s}" % (A.name.lower(), + A.indices[0])), (r"\mathbf{\hat{%s}_%s}" % + (A.name.lower(), A.indices[1])), + (r"\mathbf{\hat{%s}_%s}" % (A.name.lower(), + A.indices[2]))] + + name = 'b' + indices = [x+'1' for x in N.indices] + new_latex_vecs = [(r"\mathbf{\hat{%s}_{%s}}" % (name.lower(), + indices[0])), (r"\mathbf{\hat{%s}_{%s}}" % + (name.lower(), indices[1])), + (r"\mathbf{\hat{%s}_{%s}}" % (name.lower(), + indices[2]))] + + B = N.orientnew(name, 'Axis', [q1, N.z], latexs=new_latex_vecs) + + assert A.latex_vecs == def_latex_vecs + assert B.latex_vecs == new_latex_vecs + assert B.indices != indices + +def test_orientnew_respects_input_variables(): + N = ReferenceFrame('N') + q1 = dynamicsymbols('q1') + A = N.orientnew('a', 'Axis', [q1, N.z]) + + #build non-standard variable names + name = 'b' + new_variables = ['notb_'+x+'1' for x in N.indices] + B = N.orientnew(name, 'Axis', [q1, N.z], variables=new_variables) + + for j,var in enumerate(A.varlist): + assert var.name == A.name + '_' + A.indices[j] + + for j,var in enumerate(B.varlist): + assert var.name == new_variables[j] + +def test_issue_10348(): + u = dynamicsymbols('u:3') + I = ReferenceFrame('I') + I.orientnew('A', 'space', u, 'XYZ') + + +def test_issue_11503(): + A = ReferenceFrame("A") + A.orientnew("B", "Axis", [35, A.y]) + C = ReferenceFrame("C") + A.orient(C, "Axis", [70, C.z]) + + +def test_partial_velocity(): + + N = ReferenceFrame('N') + A = ReferenceFrame('A') + + u1, u2 = dynamicsymbols('u1, u2') + + A.set_ang_vel(N, u1 * A.x + u2 * N.y) + + assert N.partial_velocity(A, u1) == -A.x + assert N.partial_velocity(A, u1, u2) == (-A.x, -N.y) + + assert A.partial_velocity(N, u1) == A.x + assert A.partial_velocity(N, u1, u2) == (A.x, N.y) + + assert N.partial_velocity(N, u1) == 0 + assert A.partial_velocity(A, u1) == 0 + + +def test_issue_11498(): + A = ReferenceFrame('A') + B = ReferenceFrame('B') + + # Identity transformation + A.orient(B, 'DCM', eye(3)) + assert A.dcm(B) == Matrix([[1, 0, 0], [0, 1, 0], [0, 0, 1]]) + assert B.dcm(A) == Matrix([[1, 0, 0], [0, 1, 0], [0, 0, 1]]) + + # x -> y + # y -> -z + # z -> -x + A.orient(B, 'DCM', Matrix([[0, 1, 0], [0, 0, -1], [-1, 0, 0]])) + assert B.dcm(A) == Matrix([[0, 1, 0], [0, 0, -1], [-1, 0, 0]]) + assert A.dcm(B) == Matrix([[0, 0, -1], [1, 0, 0], [0, -1, 0]]) + assert B.dcm(A).T == A.dcm(B) + + +def test_reference_frame(): + raises(TypeError, lambda: ReferenceFrame(0)) + raises(TypeError, lambda: ReferenceFrame('N', 0)) + raises(ValueError, lambda: ReferenceFrame('N', [0, 1])) + raises(TypeError, lambda: ReferenceFrame('N', [0, 1, 2])) + raises(TypeError, lambda: ReferenceFrame('N', ['a', 'b', 'c'], 0)) + raises(ValueError, lambda: ReferenceFrame('N', ['a', 'b', 'c'], [0, 1])) + raises(TypeError, lambda: ReferenceFrame('N', ['a', 'b', 'c'], [0, 1, 2])) + raises(TypeError, lambda: ReferenceFrame('N', ['a', 'b', 'c'], + ['a', 'b', 'c'], 0)) + raises(ValueError, lambda: ReferenceFrame('N', ['a', 'b', 'c'], + ['a', 'b', 'c'], [0, 1])) + raises(TypeError, lambda: ReferenceFrame('N', ['a', 'b', 'c'], + ['a', 'b', 'c'], [0, 1, 2])) + N = ReferenceFrame('N') + assert N[0] == CoordinateSym('N_x', N, 0) + assert N[1] == CoordinateSym('N_y', N, 1) + assert N[2] == CoordinateSym('N_z', N, 2) + raises(ValueError, lambda: N[3]) + N = ReferenceFrame('N', ['a', 'b', 'c']) + assert N['a'] == N.x + assert N['b'] == N.y + assert N['c'] == N.z + raises(ValueError, lambda: N['d']) + assert str(N) == 'N' + + A = ReferenceFrame('A') + B = ReferenceFrame('B') + q0, q1, q2, q3 = symbols('q0 q1 q2 q3') + raises(TypeError, lambda: A.orient(B, 'DCM', 0)) + raises(TypeError, lambda: B.orient(N, 'Space', [q1, q2, q3], '222')) + raises(TypeError, lambda: B.orient(N, 'Axis', [q1, N.x + 2 * N.y], '222')) + raises(TypeError, lambda: B.orient(N, 'Axis', q1)) + raises(IndexError, lambda: B.orient(N, 'Axis', [q1])) + raises(TypeError, lambda: B.orient(N, 'Quaternion', [q0, q1, q2, q3], '222')) + raises(TypeError, lambda: B.orient(N, 'Quaternion', q0)) + raises(TypeError, lambda: B.orient(N, 'Quaternion', [q0, q1, q2])) + raises(NotImplementedError, lambda: B.orient(N, 'Foo', [q0, q1, q2])) + raises(TypeError, lambda: B.orient(N, 'Body', [q1, q2], '232')) + raises(TypeError, lambda: B.orient(N, 'Space', [q1, q2], '232')) + + N.set_ang_acc(B, 0) + assert N.ang_acc_in(B) == Vector(0) + N.set_ang_vel(B, 0) + assert N.ang_vel_in(B) == Vector(0) + + +def test_check_frame(): + raises(VectorTypeError, lambda: _check_frame(0)) + + +def test_dcm_diff_16824(): + # NOTE : This is a regression test for the bug introduced in PR 14758, + # identified in 16824, and solved by PR 16828. + + # This is the solution to Problem 2.2 on page 264 in Kane & Lenvinson's + # 1985 book. + + q1, q2, q3 = dynamicsymbols('q1:4') + + s1 = sin(q1) + c1 = cos(q1) + s2 = sin(q2) + c2 = cos(q2) + s3 = sin(q3) + c3 = cos(q3) + + dcm = Matrix([[c2*c3, s1*s2*c3 - s3*c1, c1*s2*c3 + s3*s1], + [c2*s3, s1*s2*s3 + c3*c1, c1*s2*s3 - c3*s1], + [-s2, s1*c2, c1*c2]]) + + A = ReferenceFrame('A') + B = ReferenceFrame('B') + B.orient(A, 'DCM', dcm) + + AwB = B.ang_vel_in(A) + + alpha2 = s3*c2*q1.diff() + c3*q2.diff() + beta2 = s1*c2*q3.diff() + c1*q2.diff() + + assert simplify(AwB.dot(A.y) - alpha2) == 0 + assert simplify(AwB.dot(B.y) - beta2) == 0 + +def test_orient_explicit(): + cxx, cyy, czz = dynamicsymbols('c_{xx}, c_{yy}, c_{zz}') + cxy, cxz, cyx = dynamicsymbols('c_{xy}, c_{xz}, c_{yx}') + cyz, czx, czy = dynamicsymbols('c_{yz}, c_{zx}, c_{zy}') + dcxx, dcyy, dczz = dynamicsymbols('c_{xx}, c_{yy}, c_{zz}', 1) + dcxy, dcxz, dcyx = dynamicsymbols('c_{xy}, c_{xz}, c_{yx}', 1) + dcyz, dczx, dczy = dynamicsymbols('c_{yz}, c_{zx}, c_{zy}', 1) + A = ReferenceFrame('A') + B = ReferenceFrame('B') + B_C_A = Matrix([[cxx, cxy, cxz], + [cyx, cyy, cyz], + [czx, czy, czz]]) + B_w_A = ((cyx*dczx + cyy*dczy + cyz*dczz)*B.x + + (czx*dcxx + czy*dcxy + czz*dcxz)*B.y + + (cxx*dcyx + cxy*dcyy + cxz*dcyz)*B.z) + A.orient_explicit(B, B_C_A) + assert B.dcm(A) == B_C_A + assert A.ang_vel_in(B) == B_w_A + assert B.ang_vel_in(A) == -B_w_A + +def test_orient_dcm(): + cxx, cyy, czz = dynamicsymbols('c_{xx}, c_{yy}, c_{zz}') + cxy, cxz, cyx = dynamicsymbols('c_{xy}, c_{xz}, c_{yx}') + cyz, czx, czy = dynamicsymbols('c_{yz}, c_{zx}, c_{zy}') + B_C_A = Matrix([[cxx, cxy, cxz], + [cyx, cyy, cyz], + [czx, czy, czz]]) + A = ReferenceFrame('A') + B = ReferenceFrame('B') + B.orient_dcm(A, B_C_A) + assert B.dcm(A) == Matrix([[cxx, cxy, cxz], + [cyx, cyy, cyz], + [czx, czy, czz]]) + +def test_orient_axis(): + A = ReferenceFrame('A') + B = ReferenceFrame('B') + A.orient_axis(B,-B.x, 1) + A1 = A.dcm(B) + A.orient_axis(B, B.x, -1) + A2 = A.dcm(B) + A.orient_axis(B, 1, -B.x) + A3 = A.dcm(B) + assert A1 == A2 + assert A2 == A3 + raises(TypeError, lambda: A.orient_axis(B, 1, 1)) + +def test_orient_body(): + A = ReferenceFrame('A') + B = ReferenceFrame('B') + B.orient_body_fixed(A, (1,1,0), 'XYX') + assert B.dcm(A) == Matrix([[cos(1), sin(1)**2, -sin(1)*cos(1)], [0, cos(1), sin(1)], [sin(1), -sin(1)*cos(1), cos(1)**2]]) + + +def test_orient_body_advanced(): + q1, q2, q3 = dynamicsymbols('q1:4') + c1, c2, c3 = symbols('c1:4') + u1, u2, u3 = dynamicsymbols('q1:4', 1) + + # Test with everything as dynamicsymbols + A, B = ReferenceFrame('A'), ReferenceFrame('B') + B.orient_body_fixed(A, (q1, q2, q3), 'zxy') + assert A.dcm(B) == Matrix([ + [-sin(q1) * sin(q2) * sin(q3) + cos(q1) * cos(q3), -sin(q1) * cos(q2), + sin(q1) * sin(q2) * cos(q3) + sin(q3) * cos(q1)], + [sin(q1) * cos(q3) + sin(q2) * sin(q3) * cos(q1), cos(q1) * cos(q2), + sin(q1) * sin(q3) - sin(q2) * cos(q1) * cos(q3)], + [-sin(q3) * cos(q2), sin(q2), cos(q2) * cos(q3)]]) + assert B.ang_vel_in(A).to_matrix(B) == Matrix([ + [-sin(q3) * cos(q2) * u1 + cos(q3) * u2], + [sin(q2) * u1 + u3], + [sin(q3) * u2 + cos(q2) * cos(q3) * u1]]) + + # Test with constant symbol + A, B = ReferenceFrame('A'), ReferenceFrame('B') + B.orient_body_fixed(A, (q1, c2, q3), 131) + assert A.dcm(B) == Matrix([ + [cos(c2), -sin(c2) * cos(q3), sin(c2) * sin(q3)], + [sin(c2) * cos(q1), -sin(q1) * sin(q3) + cos(c2) * cos(q1) * cos(q3), + -sin(q1) * cos(q3) - sin(q3) * cos(c2) * cos(q1)], + [sin(c2) * sin(q1), sin(q1) * cos(c2) * cos(q3) + sin(q3) * cos(q1), + -sin(q1) * sin(q3) * cos(c2) + cos(q1) * cos(q3)]]) + assert B.ang_vel_in(A).to_matrix(B) == Matrix([ + [cos(c2) * u1 + u3], + [-sin(c2) * cos(q3) * u1], + [sin(c2) * sin(q3) * u1]]) + + # Test all symbols not time dependent + A, B = ReferenceFrame('A'), ReferenceFrame('B') + B.orient_body_fixed(A, (c1, c2, c3), 123) + assert B.ang_vel_in(A) == Vector(0) + + +def test_orient_space_advanced(): + # space fixed is in the end like body fixed only in opposite order + q1, q2, q3 = dynamicsymbols('q1:4') + c1, c2, c3 = symbols('c1:4') + u1, u2, u3 = dynamicsymbols('q1:4', 1) + + # Test with everything as dynamicsymbols + A, B = ReferenceFrame('A'), ReferenceFrame('B') + B.orient_space_fixed(A, (q3, q2, q1), 'yxz') + assert A.dcm(B) == Matrix([ + [-sin(q1) * sin(q2) * sin(q3) + cos(q1) * cos(q3), -sin(q1) * cos(q2), + sin(q1) * sin(q2) * cos(q3) + sin(q3) * cos(q1)], + [sin(q1) * cos(q3) + sin(q2) * sin(q3) * cos(q1), cos(q1) * cos(q2), + sin(q1) * sin(q3) - sin(q2) * cos(q1) * cos(q3)], + [-sin(q3) * cos(q2), sin(q2), cos(q2) * cos(q3)]]) + assert B.ang_vel_in(A).to_matrix(B) == Matrix([ + [-sin(q3) * cos(q2) * u1 + cos(q3) * u2], + [sin(q2) * u1 + u3], + [sin(q3) * u2 + cos(q2) * cos(q3) * u1]]) + + # Test with constant symbol + A, B = ReferenceFrame('A'), ReferenceFrame('B') + B.orient_space_fixed(A, (q3, c2, q1), 131) + assert A.dcm(B) == Matrix([ + [cos(c2), -sin(c2) * cos(q3), sin(c2) * sin(q3)], + [sin(c2) * cos(q1), -sin(q1) * sin(q3) + cos(c2) * cos(q1) * cos(q3), + -sin(q1) * cos(q3) - sin(q3) * cos(c2) * cos(q1)], + [sin(c2) * sin(q1), sin(q1) * cos(c2) * cos(q3) + sin(q3) * cos(q1), + -sin(q1) * sin(q3) * cos(c2) + cos(q1) * cos(q3)]]) + assert B.ang_vel_in(A).to_matrix(B) == Matrix([ + [cos(c2) * u1 + u3], + [-sin(c2) * cos(q3) * u1], + [sin(c2) * sin(q3) * u1]]) + + # Test all symbols not time dependent + A, B = ReferenceFrame('A'), ReferenceFrame('B') + B.orient_space_fixed(A, (c1, c2, c3), 123) + assert B.ang_vel_in(A) == Vector(0) + + +def test_orient_body_simple_ang_vel(): + """This test ensures that the simplest form of that linear system solution + is returned, thus the == for the expression comparison.""" + + psi, theta, phi = dynamicsymbols('psi, theta, varphi') + t = dynamicsymbols._t + A = ReferenceFrame('A') + B = ReferenceFrame('B') + B.orient_body_fixed(A, (psi, theta, phi), 'ZXZ') + A_w_B = B.ang_vel_in(A) + assert A_w_B.args[0][1] == B + assert A_w_B.args[0][0][0] == (sin(theta)*sin(phi)*psi.diff(t) + + cos(phi)*theta.diff(t)) + assert A_w_B.args[0][0][1] == (sin(theta)*cos(phi)*psi.diff(t) - + sin(phi)*theta.diff(t)) + assert A_w_B.args[0][0][2] == cos(theta)*psi.diff(t) + phi.diff(t) + + +def test_orient_space(): + A = ReferenceFrame('A') + B = ReferenceFrame('B') + B.orient_space_fixed(A, (0,0,0), '123') + assert B.dcm(A) == Matrix([[1, 0, 0], [0, 1, 0], [0, 0, 1]]) + +def test_orient_quaternion(): + A = ReferenceFrame('A') + B = ReferenceFrame('B') + B.orient_quaternion(A, (0,0,0,0)) + assert B.dcm(A) == Matrix([[0, 0, 0], [0, 0, 0], [0, 0, 0]]) + +def test_looped_frame_warning(): + A = ReferenceFrame('A') + B = ReferenceFrame('B') + C = ReferenceFrame('C') + + a, b, c = symbols('a b c') + B.orient_axis(A, A.x, a) + C.orient_axis(B, B.x, b) + + with warnings.catch_warnings(record = True) as w: + warnings.simplefilter("always") + A.orient_axis(C, C.x, c) + assert issubclass(w[-1].category, UserWarning) + assert 'Loops are defined among the orientation of frames. ' + \ + 'This is likely not desired and may cause errors in your calculations.' in str(w[-1].message) + +def test_frame_dict(): + A = ReferenceFrame('A') + B = ReferenceFrame('B') + C = ReferenceFrame('C') + + a, b, c = symbols('a b c') + + B.orient_axis(A, A.x, a) + assert A._dcm_dict == {B: Matrix([[1, 0, 0],[0, cos(a), -sin(a)],[0, sin(a), cos(a)]])} + assert B._dcm_dict == {A: Matrix([[1, 0, 0],[0, cos(a), sin(a)],[0, -sin(a), cos(a)]])} + assert C._dcm_dict == {} + + B.orient_axis(C, C.x, b) + # Previous relation is not wiped + assert A._dcm_dict == {B: Matrix([[1, 0, 0],[0, cos(a), -sin(a)],[0, sin(a), cos(a)]])} + assert B._dcm_dict == {A: Matrix([[1, 0, 0],[0, cos(a), sin(a)],[0, -sin(a), cos(a)]]), \ + C: Matrix([[1, 0, 0],[0, cos(b), sin(b)],[0, -sin(b), cos(b)]])} + assert C._dcm_dict == {B: Matrix([[1, 0, 0],[0, cos(b), -sin(b)],[0, sin(b), cos(b)]])} + + A.orient_axis(B, B.x, c) + # Previous relation is updated + assert B._dcm_dict == {C: Matrix([[1, 0, 0],[0, cos(b), sin(b)],[0, -sin(b), cos(b)]]),\ + A: Matrix([[1, 0, 0],[0, cos(c), -sin(c)],[0, sin(c), cos(c)]])} + assert A._dcm_dict == {B: Matrix([[1, 0, 0],[0, cos(c), sin(c)],[0, -sin(c), cos(c)]])} + assert C._dcm_dict == {B: Matrix([[1, 0, 0],[0, cos(b), -sin(b)],[0, sin(b), cos(b)]])} + +def test_dcm_cache_dict(): + A = ReferenceFrame('A') + B = ReferenceFrame('B') + C = ReferenceFrame('C') + D = ReferenceFrame('D') + + a, b, c = symbols('a b c') + + B.orient_axis(A, A.x, a) + C.orient_axis(B, B.x, b) + D.orient_axis(C, C.x, c) + + assert D._dcm_dict == {C: Matrix([[1, 0, 0],[0, cos(c), sin(c)],[0, -sin(c), cos(c)]])} + assert C._dcm_dict == {B: Matrix([[1, 0, 0],[0, cos(b), sin(b)],[0, -sin(b), cos(b)]]), \ + D: Matrix([[1, 0, 0],[0, cos(c), -sin(c)],[0, sin(c), cos(c)]])} + assert B._dcm_dict == {A: Matrix([[1, 0, 0],[0, cos(a), sin(a)],[0, -sin(a), cos(a)]]), \ + C: Matrix([[1, 0, 0],[0, cos(b), -sin(b)],[0, sin(b), cos(b)]])} + assert A._dcm_dict == {B: Matrix([[1, 0, 0],[0, cos(a), -sin(a)],[0, sin(a), cos(a)]])} + + assert D._dcm_dict == D._dcm_cache + + D.dcm(A) # Check calculated dcm relation is stored in _dcm_cache and not in _dcm_dict + assert list(A._dcm_cache.keys()) == [A, B, D] + assert list(D._dcm_cache.keys()) == [C, A] + assert list(A._dcm_dict.keys()) == [B] + assert list(D._dcm_dict.keys()) == [C] + assert A._dcm_dict != A._dcm_cache + + A.orient_axis(B, B.x, b) # _dcm_cache of A is wiped out and new relation is stored. + assert A._dcm_dict == {B: Matrix([[1, 0, 0],[0, cos(b), sin(b)],[0, -sin(b), cos(b)]])} + assert A._dcm_dict == A._dcm_cache + assert B._dcm_dict == {C: Matrix([[1, 0, 0],[0, cos(b), -sin(b)],[0, sin(b), cos(b)]]), \ + A: Matrix([[1, 0, 0],[0, cos(b), -sin(b)],[0, sin(b), cos(b)]])} + +def test_xx_dyad(): + N = ReferenceFrame('N') + F = ReferenceFrame('F', indices=['1', '2', '3']) + assert N.xx == Vector.outer(N.x, N.x) + assert F.xx == Vector.outer(F.x, F.x) + +def test_xy_dyad(): + N = ReferenceFrame('N') + F = ReferenceFrame('F', indices=['1', '2', '3']) + assert N.xy == Vector.outer(N.x, N.y) + assert F.xy == Vector.outer(F.x, F.y) + +def test_xz_dyad(): + N = ReferenceFrame('N') + F = ReferenceFrame('F', indices=['1', '2', '3']) + assert N.xz == Vector.outer(N.x, N.z) + assert F.xz == Vector.outer(F.x, F.z) + +def test_yx_dyad(): + N = ReferenceFrame('N') + F = ReferenceFrame('F', indices=['1', '2', '3']) + assert N.yx == Vector.outer(N.y, N.x) + assert F.yx == Vector.outer(F.y, F.x) + +def test_yy_dyad(): + N = ReferenceFrame('N') + F = ReferenceFrame('F', indices=['1', '2', '3']) + assert N.yy == Vector.outer(N.y, N.y) + assert F.yy == Vector.outer(F.y, F.y) + +def test_yz_dyad(): + N = ReferenceFrame('N') + F = ReferenceFrame('F', indices=['1', '2', '3']) + assert N.yz == Vector.outer(N.y, N.z) + assert F.yz == Vector.outer(F.y, F.z) + +def test_zx_dyad(): + N = ReferenceFrame('N') + F = ReferenceFrame('F', indices=['1', '2', '3']) + assert N.zx == Vector.outer(N.z, N.x) + assert F.zx == Vector.outer(F.z, F.x) + +def test_zy_dyad(): + N = ReferenceFrame('N') + F = ReferenceFrame('F', indices=['1', '2', '3']) + assert N.zy == Vector.outer(N.z, N.y) + assert F.zy == Vector.outer(F.z, F.y) + +def test_zz_dyad(): + N = ReferenceFrame('N') + F = ReferenceFrame('F', indices=['1', '2', '3']) + assert N.zz == Vector.outer(N.z, N.z) + assert F.zz == Vector.outer(F.z, F.z) + +def test_unit_dyadic(): + N = ReferenceFrame('N') + F = ReferenceFrame('F', indices=['1', '2', '3']) + assert N.u == N.xx + N.yy + N.zz + assert F.u == F.xx + F.yy + F.zz + + +def test_pickle_frame(): + N = ReferenceFrame('N') + A = ReferenceFrame('A') + A.orient_axis(N, N.x, 1) + A_C_N = A.dcm(N) + N1 = pickle.loads(pickle.dumps(N)) + A1 = tuple(N1._dcm_dict.keys())[0] + assert A1.dcm(N1) == A_C_N diff --git a/lib/python3.12/site-packages/sympy/physics/vector/tests/test_functions.py b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_functions.py new file mode 100644 index 0000000000000000000000000000000000000000..ff938da980c4bbd51d378b30fd5310a88e528e97 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_functions.py @@ -0,0 +1,509 @@ +from sympy.core.numbers import pi +from sympy.core.singleton import S +from sympy.core.symbol import symbols +from sympy.functions.elementary.miscellaneous import sqrt +from sympy.functions.elementary.trigonometric import (cos, sin) +from sympy.integrals.integrals import Integral +from sympy.physics.vector import Dyadic, Point, ReferenceFrame, Vector +from sympy.physics.vector.functions import (cross, dot, express, + time_derivative, + kinematic_equations, outer, + partial_velocity, + get_motion_params, dynamicsymbols) +from sympy.simplify import trigsimp +from sympy.testing.pytest import raises + +q1, q2, q3, q4, q5 = symbols('q1 q2 q3 q4 q5') +N = ReferenceFrame('N') +A = N.orientnew('A', 'Axis', [q1, N.z]) +B = A.orientnew('B', 'Axis', [q2, A.x]) +C = B.orientnew('C', 'Axis', [q3, B.y]) + + +def test_dot(): + assert dot(A.x, A.x) == 1 + assert dot(A.x, A.y) == 0 + assert dot(A.x, A.z) == 0 + + assert dot(A.y, A.x) == 0 + assert dot(A.y, A.y) == 1 + assert dot(A.y, A.z) == 0 + + assert dot(A.z, A.x) == 0 + assert dot(A.z, A.y) == 0 + assert dot(A.z, A.z) == 1 + + +def test_dot_different_frames(): + assert dot(N.x, A.x) == cos(q1) + assert dot(N.x, A.y) == -sin(q1) + assert dot(N.x, A.z) == 0 + assert dot(N.y, A.x) == sin(q1) + assert dot(N.y, A.y) == cos(q1) + assert dot(N.y, A.z) == 0 + assert dot(N.z, A.x) == 0 + assert dot(N.z, A.y) == 0 + assert dot(N.z, A.z) == 1 + + assert trigsimp(dot(N.x, A.x + A.y)) == sqrt(2)*cos(q1 + pi/4) + assert trigsimp(dot(N.x, A.x + A.y)) == trigsimp(dot(A.x + A.y, N.x)) + + assert dot(A.x, C.x) == cos(q3) + assert dot(A.x, C.y) == 0 + assert dot(A.x, C.z) == sin(q3) + assert dot(A.y, C.x) == sin(q2)*sin(q3) + assert dot(A.y, C.y) == cos(q2) + assert dot(A.y, C.z) == -sin(q2)*cos(q3) + assert dot(A.z, C.x) == -cos(q2)*sin(q3) + assert dot(A.z, C.y) == sin(q2) + assert dot(A.z, C.z) == cos(q2)*cos(q3) + + +def test_cross(): + assert cross(A.x, A.x) == 0 + assert cross(A.x, A.y) == A.z + assert cross(A.x, A.z) == -A.y + + assert cross(A.y, A.x) == -A.z + assert cross(A.y, A.y) == 0 + assert cross(A.y, A.z) == A.x + + assert cross(A.z, A.x) == A.y + assert cross(A.z, A.y) == -A.x + assert cross(A.z, A.z) == 0 + + +def test_cross_different_frames(): + assert cross(N.x, A.x) == sin(q1)*A.z + assert cross(N.x, A.y) == cos(q1)*A.z + assert cross(N.x, A.z) == -sin(q1)*A.x - cos(q1)*A.y + assert cross(N.y, A.x) == -cos(q1)*A.z + assert cross(N.y, A.y) == sin(q1)*A.z + assert cross(N.y, A.z) == cos(q1)*A.x - sin(q1)*A.y + assert cross(N.z, A.x) == A.y + assert cross(N.z, A.y) == -A.x + assert cross(N.z, A.z) == 0 + + assert cross(N.x, A.x) == sin(q1)*A.z + assert cross(N.x, A.y) == cos(q1)*A.z + assert cross(N.x, A.x + A.y) == sin(q1)*A.z + cos(q1)*A.z + assert cross(A.x + A.y, N.x) == -sin(q1)*A.z - cos(q1)*A.z + + assert cross(A.x, C.x) == sin(q3)*C.y + assert cross(A.x, C.y) == -sin(q3)*C.x + cos(q3)*C.z + assert cross(A.x, C.z) == -cos(q3)*C.y + assert cross(C.x, A.x) == -sin(q3)*C.y + assert cross(C.y, A.x).express(C).simplify() == sin(q3)*C.x - cos(q3)*C.z + assert cross(C.z, A.x) == cos(q3)*C.y + +def test_operator_match(): + """Test that the output of dot, cross, outer functions match + operator behavior. + """ + A = ReferenceFrame('A') + v = A.x + A.y + d = v | v + zerov = Vector(0) + zerod = Dyadic(0) + + # dot products + assert d & d == dot(d, d) + assert d & zerod == dot(d, zerod) + assert zerod & d == dot(zerod, d) + assert d & v == dot(d, v) + assert v & d == dot(v, d) + assert d & zerov == dot(d, zerov) + assert zerov & d == dot(zerov, d) + raises(TypeError, lambda: dot(d, S.Zero)) + raises(TypeError, lambda: dot(S.Zero, d)) + raises(TypeError, lambda: dot(d, 0)) + raises(TypeError, lambda: dot(0, d)) + assert v & v == dot(v, v) + assert v & zerov == dot(v, zerov) + assert zerov & v == dot(zerov, v) + raises(TypeError, lambda: dot(v, S.Zero)) + raises(TypeError, lambda: dot(S.Zero, v)) + raises(TypeError, lambda: dot(v, 0)) + raises(TypeError, lambda: dot(0, v)) + + # cross products + raises(TypeError, lambda: cross(d, d)) + raises(TypeError, lambda: cross(d, zerod)) + raises(TypeError, lambda: cross(zerod, d)) + assert d ^ v == cross(d, v) + assert v ^ d == cross(v, d) + assert d ^ zerov == cross(d, zerov) + assert zerov ^ d == cross(zerov, d) + assert zerov ^ d == cross(zerov, d) + raises(TypeError, lambda: cross(d, S.Zero)) + raises(TypeError, lambda: cross(S.Zero, d)) + raises(TypeError, lambda: cross(d, 0)) + raises(TypeError, lambda: cross(0, d)) + assert v ^ v == cross(v, v) + assert v ^ zerov == cross(v, zerov) + assert zerov ^ v == cross(zerov, v) + raises(TypeError, lambda: cross(v, S.Zero)) + raises(TypeError, lambda: cross(S.Zero, v)) + raises(TypeError, lambda: cross(v, 0)) + raises(TypeError, lambda: cross(0, v)) + + # outer products + raises(TypeError, lambda: outer(d, d)) + raises(TypeError, lambda: outer(d, zerod)) + raises(TypeError, lambda: outer(zerod, d)) + raises(TypeError, lambda: outer(d, v)) + raises(TypeError, lambda: outer(v, d)) + raises(TypeError, lambda: outer(d, zerov)) + raises(TypeError, lambda: outer(zerov, d)) + raises(TypeError, lambda: outer(zerov, d)) + raises(TypeError, lambda: outer(d, S.Zero)) + raises(TypeError, lambda: outer(S.Zero, d)) + raises(TypeError, lambda: outer(d, 0)) + raises(TypeError, lambda: outer(0, d)) + assert v | v == outer(v, v) + assert v | zerov == outer(v, zerov) + assert zerov | v == outer(zerov, v) + raises(TypeError, lambda: outer(v, S.Zero)) + raises(TypeError, lambda: outer(S.Zero, v)) + raises(TypeError, lambda: outer(v, 0)) + raises(TypeError, lambda: outer(0, v)) + + +def test_express(): + assert express(Vector(0), N) == Vector(0) + assert express(S.Zero, N) is S.Zero + assert express(A.x, C) == cos(q3)*C.x + sin(q3)*C.z + assert express(A.y, C) == sin(q2)*sin(q3)*C.x + cos(q2)*C.y - \ + sin(q2)*cos(q3)*C.z + assert express(A.z, C) == -sin(q3)*cos(q2)*C.x + sin(q2)*C.y + \ + cos(q2)*cos(q3)*C.z + assert express(A.x, N) == cos(q1)*N.x + sin(q1)*N.y + assert express(A.y, N) == -sin(q1)*N.x + cos(q1)*N.y + assert express(A.z, N) == N.z + assert express(A.x, A) == A.x + assert express(A.y, A) == A.y + assert express(A.z, A) == A.z + assert express(A.x, B) == B.x + assert express(A.y, B) == cos(q2)*B.y - sin(q2)*B.z + assert express(A.z, B) == sin(q2)*B.y + cos(q2)*B.z + assert express(A.x, C) == cos(q3)*C.x + sin(q3)*C.z + assert express(A.y, C) == sin(q2)*sin(q3)*C.x + cos(q2)*C.y - \ + sin(q2)*cos(q3)*C.z + assert express(A.z, C) == -sin(q3)*cos(q2)*C.x + sin(q2)*C.y + \ + cos(q2)*cos(q3)*C.z + # Check to make sure UnitVectors get converted properly + assert express(N.x, N) == N.x + assert express(N.y, N) == N.y + assert express(N.z, N) == N.z + assert express(N.x, A) == (cos(q1)*A.x - sin(q1)*A.y) + assert express(N.y, A) == (sin(q1)*A.x + cos(q1)*A.y) + assert express(N.z, A) == A.z + assert express(N.x, B) == (cos(q1)*B.x - sin(q1)*cos(q2)*B.y + + sin(q1)*sin(q2)*B.z) + assert express(N.y, B) == (sin(q1)*B.x + cos(q1)*cos(q2)*B.y - + sin(q2)*cos(q1)*B.z) + assert express(N.z, B) == (sin(q2)*B.y + cos(q2)*B.z) + assert express(N.x, C) == ( + (cos(q1)*cos(q3) - sin(q1)*sin(q2)*sin(q3))*C.x - + sin(q1)*cos(q2)*C.y + + (sin(q3)*cos(q1) + sin(q1)*sin(q2)*cos(q3))*C.z) + assert express(N.y, C) == ( + (sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1))*C.x + + cos(q1)*cos(q2)*C.y + + (sin(q1)*sin(q3) - sin(q2)*cos(q1)*cos(q3))*C.z) + assert express(N.z, C) == (-sin(q3)*cos(q2)*C.x + sin(q2)*C.y + + cos(q2)*cos(q3)*C.z) + + assert express(A.x, N) == (cos(q1)*N.x + sin(q1)*N.y) + assert express(A.y, N) == (-sin(q1)*N.x + cos(q1)*N.y) + assert express(A.z, N) == N.z + assert express(A.x, A) == A.x + assert express(A.y, A) == A.y + assert express(A.z, A) == A.z + assert express(A.x, B) == B.x + assert express(A.y, B) == (cos(q2)*B.y - sin(q2)*B.z) + assert express(A.z, B) == (sin(q2)*B.y + cos(q2)*B.z) + assert express(A.x, C) == (cos(q3)*C.x + sin(q3)*C.z) + assert express(A.y, C) == (sin(q2)*sin(q3)*C.x + cos(q2)*C.y - + sin(q2)*cos(q3)*C.z) + assert express(A.z, C) == (-sin(q3)*cos(q2)*C.x + sin(q2)*C.y + + cos(q2)*cos(q3)*C.z) + + assert express(B.x, N) == (cos(q1)*N.x + sin(q1)*N.y) + assert express(B.y, N) == (-sin(q1)*cos(q2)*N.x + + cos(q1)*cos(q2)*N.y + sin(q2)*N.z) + assert express(B.z, N) == (sin(q1)*sin(q2)*N.x - + sin(q2)*cos(q1)*N.y + cos(q2)*N.z) + assert express(B.x, A) == A.x + assert express(B.y, A) == (cos(q2)*A.y + sin(q2)*A.z) + assert express(B.z, A) == (-sin(q2)*A.y + cos(q2)*A.z) + assert express(B.x, B) == B.x + assert express(B.y, B) == B.y + assert express(B.z, B) == B.z + assert express(B.x, C) == (cos(q3)*C.x + sin(q3)*C.z) + assert express(B.y, C) == C.y + assert express(B.z, C) == (-sin(q3)*C.x + cos(q3)*C.z) + + assert express(C.x, N) == ( + (cos(q1)*cos(q3) - sin(q1)*sin(q2)*sin(q3))*N.x + + (sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1))*N.y - + sin(q3)*cos(q2)*N.z) + assert express(C.y, N) == ( + -sin(q1)*cos(q2)*N.x + cos(q1)*cos(q2)*N.y + sin(q2)*N.z) + assert express(C.z, N) == ( + (sin(q3)*cos(q1) + sin(q1)*sin(q2)*cos(q3))*N.x + + (sin(q1)*sin(q3) - sin(q2)*cos(q1)*cos(q3))*N.y + + cos(q2)*cos(q3)*N.z) + assert express(C.x, A) == (cos(q3)*A.x + sin(q2)*sin(q3)*A.y - + sin(q3)*cos(q2)*A.z) + assert express(C.y, A) == (cos(q2)*A.y + sin(q2)*A.z) + assert express(C.z, A) == (sin(q3)*A.x - sin(q2)*cos(q3)*A.y + + cos(q2)*cos(q3)*A.z) + assert express(C.x, B) == (cos(q3)*B.x - sin(q3)*B.z) + assert express(C.y, B) == B.y + assert express(C.z, B) == (sin(q3)*B.x + cos(q3)*B.z) + assert express(C.x, C) == C.x + assert express(C.y, C) == C.y + assert express(C.z, C) == C.z == (C.z) + + # Check to make sure Vectors get converted back to UnitVectors + assert N.x == express((cos(q1)*A.x - sin(q1)*A.y), N).simplify() + assert N.y == express((sin(q1)*A.x + cos(q1)*A.y), N).simplify() + assert N.x == express((cos(q1)*B.x - sin(q1)*cos(q2)*B.y + + sin(q1)*sin(q2)*B.z), N).simplify() + assert N.y == express((sin(q1)*B.x + cos(q1)*cos(q2)*B.y - + sin(q2)*cos(q1)*B.z), N).simplify() + assert N.z == express((sin(q2)*B.y + cos(q2)*B.z), N).simplify() + + """ + These don't really test our code, they instead test the auto simplification + (or lack thereof) of SymPy. + assert N.x == express(( + (cos(q1)*cos(q3)-sin(q1)*sin(q2)*sin(q3))*C.x - + sin(q1)*cos(q2)*C.y + + (sin(q3)*cos(q1)+sin(q1)*sin(q2)*cos(q3))*C.z), N) + assert N.y == express(( + (sin(q1)*cos(q3) + sin(q2)*sin(q3)*cos(q1))*C.x + + cos(q1)*cos(q2)*C.y + + (sin(q1)*sin(q3) - sin(q2)*cos(q1)*cos(q3))*C.z), N) + assert N.z == express((-sin(q3)*cos(q2)*C.x + sin(q2)*C.y + + cos(q2)*cos(q3)*C.z), N) + """ + + assert A.x == express((cos(q1)*N.x + sin(q1)*N.y), A).simplify() + assert A.y == express((-sin(q1)*N.x + cos(q1)*N.y), A).simplify() + + assert A.y == express((cos(q2)*B.y - sin(q2)*B.z), A).simplify() + assert A.z == express((sin(q2)*B.y + cos(q2)*B.z), A).simplify() + + assert A.x == express((cos(q3)*C.x + sin(q3)*C.z), A).simplify() + + # Tripsimp messes up here too. + #print express((sin(q2)*sin(q3)*C.x + cos(q2)*C.y - + # sin(q2)*cos(q3)*C.z), A) + assert A.y == express((sin(q2)*sin(q3)*C.x + cos(q2)*C.y - + sin(q2)*cos(q3)*C.z), A).simplify() + + assert A.z == express((-sin(q3)*cos(q2)*C.x + sin(q2)*C.y + + cos(q2)*cos(q3)*C.z), A).simplify() + assert B.x == express((cos(q1)*N.x + sin(q1)*N.y), B).simplify() + assert B.y == express((-sin(q1)*cos(q2)*N.x + + cos(q1)*cos(q2)*N.y + sin(q2)*N.z), B).simplify() + + assert B.z == express((sin(q1)*sin(q2)*N.x - + sin(q2)*cos(q1)*N.y + cos(q2)*N.z), B).simplify() + + assert B.y == express((cos(q2)*A.y + sin(q2)*A.z), B).simplify() + assert B.z == express((-sin(q2)*A.y + cos(q2)*A.z), B).simplify() + assert B.x == express((cos(q3)*C.x + sin(q3)*C.z), B).simplify() + assert B.z == express((-sin(q3)*C.x + cos(q3)*C.z), B).simplify() + + """ + assert C.x == express(( + (cos(q1)*cos(q3)-sin(q1)*sin(q2)*sin(q3))*N.x + + (sin(q1)*cos(q3)+sin(q2)*sin(q3)*cos(q1))*N.y - + sin(q3)*cos(q2)*N.z), C) + assert C.y == express(( + -sin(q1)*cos(q2)*N.x + cos(q1)*cos(q2)*N.y + sin(q2)*N.z), C) + assert C.z == express(( + (sin(q3)*cos(q1)+sin(q1)*sin(q2)*cos(q3))*N.x + + (sin(q1)*sin(q3)-sin(q2)*cos(q1)*cos(q3))*N.y + + cos(q2)*cos(q3)*N.z), C) + """ + assert C.x == express((cos(q3)*A.x + sin(q2)*sin(q3)*A.y - + sin(q3)*cos(q2)*A.z), C).simplify() + assert C.y == express((cos(q2)*A.y + sin(q2)*A.z), C).simplify() + assert C.z == express((sin(q3)*A.x - sin(q2)*cos(q3)*A.y + + cos(q2)*cos(q3)*A.z), C).simplify() + assert C.x == express((cos(q3)*B.x - sin(q3)*B.z), C).simplify() + assert C.z == express((sin(q3)*B.x + cos(q3)*B.z), C).simplify() + + +def test_time_derivative(): + #The use of time_derivative for calculations pertaining to scalar + #fields has been tested in test_coordinate_vars in test_essential.py + A = ReferenceFrame('A') + q = dynamicsymbols('q') + qd = dynamicsymbols('q', 1) + B = A.orientnew('B', 'Axis', [q, A.z]) + d = A.x | A.x + assert time_derivative(d, B) == (-qd) * (A.y | A.x) + \ + (-qd) * (A.x | A.y) + d1 = A.x | B.y + assert time_derivative(d1, A) == - qd*(A.x|B.x) + assert time_derivative(d1, B) == - qd*(A.y|B.y) + d2 = A.x | B.x + assert time_derivative(d2, A) == qd*(A.x|B.y) + assert time_derivative(d2, B) == - qd*(A.y|B.x) + d3 = A.x | B.z + assert time_derivative(d3, A) == 0 + assert time_derivative(d3, B) == - qd*(A.y|B.z) + q1, q2, q3, q4 = dynamicsymbols('q1 q2 q3 q4') + q1d, q2d, q3d, q4d = dynamicsymbols('q1 q2 q3 q4', 1) + q1dd, q2dd, q3dd, q4dd = dynamicsymbols('q1 q2 q3 q4', 2) + C = B.orientnew('C', 'Axis', [q4, B.x]) + v1 = q1 * A.z + v2 = q2*A.x + q3*B.y + v3 = q1*A.x + q2*A.y + q3*A.z + assert time_derivative(B.x, C) == 0 + assert time_derivative(B.y, C) == - q4d*B.z + assert time_derivative(B.z, C) == q4d*B.y + assert time_derivative(v1, B) == q1d*A.z + assert time_derivative(v1, C) == - q1*sin(q)*q4d*A.x + \ + q1*cos(q)*q4d*A.y + q1d*A.z + assert time_derivative(v2, A) == q2d*A.x - q3*qd*B.x + q3d*B.y + assert time_derivative(v2, C) == q2d*A.x - q2*qd*A.y + \ + q2*sin(q)*q4d*A.z + q3d*B.y - q3*q4d*B.z + assert time_derivative(v3, B) == (q2*qd + q1d)*A.x + \ + (-q1*qd + q2d)*A.y + q3d*A.z + assert time_derivative(d, C) == - qd*(A.y|A.x) + \ + sin(q)*q4d*(A.z|A.x) - qd*(A.x|A.y) + sin(q)*q4d*(A.x|A.z) + raises(ValueError, lambda: time_derivative(B.x, C, order=0.5)) + raises(ValueError, lambda: time_derivative(B.x, C, order=-1)) + + +def test_get_motion_methods(): + #Initialization + t = dynamicsymbols._t + s1, s2, s3 = symbols('s1 s2 s3') + S1, S2, S3 = symbols('S1 S2 S3') + S4, S5, S6 = symbols('S4 S5 S6') + t1, t2 = symbols('t1 t2') + a, b, c = dynamicsymbols('a b c') + ad, bd, cd = dynamicsymbols('a b c', 1) + a2d, b2d, c2d = dynamicsymbols('a b c', 2) + v0 = S1*N.x + S2*N.y + S3*N.z + v01 = S4*N.x + S5*N.y + S6*N.z + v1 = s1*N.x + s2*N.y + s3*N.z + v2 = a*N.x + b*N.y + c*N.z + v2d = ad*N.x + bd*N.y + cd*N.z + v2dd = a2d*N.x + b2d*N.y + c2d*N.z + #Test position parameter + assert get_motion_params(frame = N) == (0, 0, 0) + assert get_motion_params(N, position=v1) == (0, 0, v1) + assert get_motion_params(N, position=v2) == (v2dd, v2d, v2) + #Test velocity parameter + assert get_motion_params(N, velocity=v1) == (0, v1, v1 * t) + assert get_motion_params(N, velocity=v1, position=v0, timevalue1=t1) == \ + (0, v1, v0 + v1*(t - t1)) + answer = get_motion_params(N, velocity=v1, position=v2, timevalue1=t1) + answer_expected = (0, v1, v1*t - v1*t1 + v2.subs(t, t1)) + assert answer == answer_expected + + answer = get_motion_params(N, velocity=v2, position=v0, timevalue1=t1) + integral_vector = Integral(a, (t, t1, t))*N.x + Integral(b, (t, t1, t))*N.y \ + + Integral(c, (t, t1, t))*N.z + answer_expected = (v2d, v2, v0 + integral_vector) + assert answer == answer_expected + + #Test acceleration parameter + assert get_motion_params(N, acceleration=v1) == \ + (v1, v1 * t, v1 * t**2/2) + assert get_motion_params(N, acceleration=v1, velocity=v0, + position=v2, timevalue1=t1, timevalue2=t2) == \ + (v1, (v0 + v1*t - v1*t2), + -v0*t1 + v1*t**2/2 + v1*t2*t1 - \ + v1*t1**2/2 + t*(v0 - v1*t2) + \ + v2.subs(t, t1)) + assert get_motion_params(N, acceleration=v1, velocity=v0, + position=v01, timevalue1=t1, timevalue2=t2) == \ + (v1, v0 + v1*t - v1*t2, + -v0*t1 + v01 + v1*t**2/2 + \ + v1*t2*t1 - v1*t1**2/2 + \ + t*(v0 - v1*t2)) + answer = get_motion_params(N, acceleration=a*N.x, velocity=S1*N.x, + position=S2*N.x, timevalue1=t1, timevalue2=t2) + i1 = Integral(a, (t, t2, t)) + answer_expected = (a*N.x, (S1 + i1)*N.x, \ + (S2 + Integral(S1 + i1, (t, t1, t)))*N.x) + assert answer == answer_expected + + +def test_kin_eqs(): + q0, q1, q2, q3 = dynamicsymbols('q0 q1 q2 q3') + q0d, q1d, q2d, q3d = dynamicsymbols('q0 q1 q2 q3', 1) + u1, u2, u3 = dynamicsymbols('u1 u2 u3') + ke = kinematic_equations([u1,u2,u3], [q1,q2,q3], 'body', 313) + assert ke == kinematic_equations([u1,u2,u3], [q1,q2,q3], 'body', '313') + kds = kinematic_equations([u1, u2, u3], [q0, q1, q2, q3], 'quaternion') + assert kds == [-0.5 * q0 * u1 - 0.5 * q2 * u3 + 0.5 * q3 * u2 + q1d, + -0.5 * q0 * u2 + 0.5 * q1 * u3 - 0.5 * q3 * u1 + q2d, + -0.5 * q0 * u3 - 0.5 * q1 * u2 + 0.5 * q2 * u1 + q3d, + 0.5 * q1 * u1 + 0.5 * q2 * u2 + 0.5 * q3 * u3 + q0d] + raises(ValueError, lambda: kinematic_equations([u1, u2, u3], [q0, q1, q2], 'quaternion')) + raises(ValueError, lambda: kinematic_equations([u1, u2, u3], [q0, q1, q2, q3], 'quaternion', '123')) + raises(ValueError, lambda: kinematic_equations([u1, u2, u3], [q0, q1, q2, q3], 'foo')) + raises(TypeError, lambda: kinematic_equations(u1, [q0, q1, q2, q3], 'quaternion')) + raises(TypeError, lambda: kinematic_equations([u1], [q0, q1, q2, q3], 'quaternion')) + raises(TypeError, lambda: kinematic_equations([u1, u2, u3], q0, 'quaternion')) + raises(ValueError, lambda: kinematic_equations([u1, u2, u3], [q0, q1, q2, q3], 'body')) + raises(ValueError, lambda: kinematic_equations([u1, u2, u3], [q0, q1, q2, q3], 'space')) + raises(ValueError, lambda: kinematic_equations([u1, u2, u3], [q0, q1, q2], 'body', '222')) + assert kinematic_equations([0, 0, 0], [q0, q1, q2], 'space') == [S.Zero, S.Zero, S.Zero] + + +def test_partial_velocity(): + q1, q2, q3, u1, u2, u3 = dynamicsymbols('q1 q2 q3 u1 u2 u3') + u4, u5 = dynamicsymbols('u4, u5') + r = symbols('r') + + N = ReferenceFrame('N') + Y = N.orientnew('Y', 'Axis', [q1, N.z]) + L = Y.orientnew('L', 'Axis', [q2, Y.x]) + R = L.orientnew('R', 'Axis', [q3, L.y]) + R.set_ang_vel(N, u1 * L.x + u2 * L.y + u3 * L.z) + + C = Point('C') + C.set_vel(N, u4 * L.x + u5 * (Y.z ^ L.x)) + Dmc = C.locatenew('Dmc', r * L.z) + Dmc.v2pt_theory(C, N, R) + + vel_list = [Dmc.vel(N), C.vel(N), R.ang_vel_in(N)] + u_list = [u1, u2, u3, u4, u5] + assert (partial_velocity(vel_list, u_list, N) == + [[- r*L.y, r*L.x, 0, L.x, cos(q2)*L.y - sin(q2)*L.z], + [0, 0, 0, L.x, cos(q2)*L.y - sin(q2)*L.z], + [L.x, L.y, L.z, 0, 0]]) + + # Make sure that partial velocities can be computed regardless if the + # orientation between frames is defined or not. + A = ReferenceFrame('A') + B = ReferenceFrame('B') + v = u4 * A.x + u5 * B.y + assert partial_velocity((v, ), (u4, u5), A) == [[A.x, B.y]] + + raises(TypeError, lambda: partial_velocity(Dmc.vel(N), u_list, N)) + raises(TypeError, lambda: partial_velocity(vel_list, u1, N)) + +def test_dynamicsymbols(): + #Tests to check the assumptions applied to dynamicsymbols + f1 = dynamicsymbols('f1') + f2 = dynamicsymbols('f2', real=True) + f3 = dynamicsymbols('f3', positive=True) + f4, f5 = dynamicsymbols('f4,f5', commutative=False) + f6 = dynamicsymbols('f6', integer=True) + assert f1.is_real is None + assert f2.is_real + assert f3.is_positive + assert f4*f5 != f5*f4 + assert f6.is_integer diff --git a/lib/python3.12/site-packages/sympy/physics/vector/tests/test_output.py b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_output.py new file mode 100644 index 0000000000000000000000000000000000000000..e02f3e5962bc23bbb62929e343a5afac574a2570 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_output.py @@ -0,0 +1,75 @@ +from sympy.core.singleton import S +from sympy.physics.vector import Vector, ReferenceFrame, Dyadic +from sympy.testing.pytest import raises + +A = ReferenceFrame('A') + + +def test_output_type(): + A = ReferenceFrame('A') + v = A.x + A.y + d = v | v + zerov = Vector(0) + zerod = Dyadic(0) + + # dot products + assert isinstance(d & d, Dyadic) + assert isinstance(d & zerod, Dyadic) + assert isinstance(zerod & d, Dyadic) + assert isinstance(d & v, Vector) + assert isinstance(v & d, Vector) + assert isinstance(d & zerov, Vector) + assert isinstance(zerov & d, Vector) + raises(TypeError, lambda: d & S.Zero) + raises(TypeError, lambda: S.Zero & d) + raises(TypeError, lambda: d & 0) + raises(TypeError, lambda: 0 & d) + assert not isinstance(v & v, (Vector, Dyadic)) + assert not isinstance(v & zerov, (Vector, Dyadic)) + assert not isinstance(zerov & v, (Vector, Dyadic)) + raises(TypeError, lambda: v & S.Zero) + raises(TypeError, lambda: S.Zero & v) + raises(TypeError, lambda: v & 0) + raises(TypeError, lambda: 0 & v) + + # cross products + raises(TypeError, lambda: d ^ d) + raises(TypeError, lambda: d ^ zerod) + raises(TypeError, lambda: zerod ^ d) + assert isinstance(d ^ v, Dyadic) + assert isinstance(v ^ d, Dyadic) + assert isinstance(d ^ zerov, Dyadic) + assert isinstance(zerov ^ d, Dyadic) + assert isinstance(zerov ^ d, Dyadic) + raises(TypeError, lambda: d ^ S.Zero) + raises(TypeError, lambda: S.Zero ^ d) + raises(TypeError, lambda: d ^ 0) + raises(TypeError, lambda: 0 ^ d) + assert isinstance(v ^ v, Vector) + assert isinstance(v ^ zerov, Vector) + assert isinstance(zerov ^ v, Vector) + raises(TypeError, lambda: v ^ S.Zero) + raises(TypeError, lambda: S.Zero ^ v) + raises(TypeError, lambda: v ^ 0) + raises(TypeError, lambda: 0 ^ v) + + # outer products + raises(TypeError, lambda: d | d) + raises(TypeError, lambda: d | zerod) + raises(TypeError, lambda: zerod | d) + raises(TypeError, lambda: d | v) + raises(TypeError, lambda: v | d) + raises(TypeError, lambda: d | zerov) + raises(TypeError, lambda: zerov | d) + raises(TypeError, lambda: zerov | d) + raises(TypeError, lambda: d | S.Zero) + raises(TypeError, lambda: S.Zero | d) + raises(TypeError, lambda: d | 0) + raises(TypeError, lambda: 0 | d) + assert isinstance(v | v, Dyadic) + assert isinstance(v | zerov, Dyadic) + assert isinstance(zerov | v, Dyadic) + raises(TypeError, lambda: v | S.Zero) + raises(TypeError, lambda: S.Zero | v) + raises(TypeError, lambda: v | 0) + raises(TypeError, lambda: 0 | v) diff --git a/lib/python3.12/site-packages/sympy/physics/vector/tests/test_point.py b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_point.py new file mode 100644 index 0000000000000000000000000000000000000000..0e0c8b092ef61c590d3c713cef25feb3e64051c6 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_point.py @@ -0,0 +1,382 @@ +from sympy.physics.vector import dynamicsymbols, Point, ReferenceFrame +from sympy.testing.pytest import raises, ignore_warnings +import warnings + +def test_point_v1pt_theorys(): + q, q2 = dynamicsymbols('q q2') + qd, q2d = dynamicsymbols('q q2', 1) + qdd, q2dd = dynamicsymbols('q q2', 2) + N = ReferenceFrame('N') + B = ReferenceFrame('B') + B.set_ang_vel(N, qd * B.z) + O = Point('O') + P = O.locatenew('P', B.x) + P.set_vel(B, 0) + O.set_vel(N, 0) + assert P.v1pt_theory(O, N, B) == qd * B.y + O.set_vel(N, N.x) + assert P.v1pt_theory(O, N, B) == N.x + qd * B.y + P.set_vel(B, B.z) + assert P.v1pt_theory(O, N, B) == B.z + N.x + qd * B.y + + +def test_point_a1pt_theorys(): + q, q2 = dynamicsymbols('q q2') + qd, q2d = dynamicsymbols('q q2', 1) + qdd, q2dd = dynamicsymbols('q q2', 2) + N = ReferenceFrame('N') + B = ReferenceFrame('B') + B.set_ang_vel(N, qd * B.z) + O = Point('O') + P = O.locatenew('P', B.x) + P.set_vel(B, 0) + O.set_vel(N, 0) + assert P.a1pt_theory(O, N, B) == -(qd**2) * B.x + qdd * B.y + P.set_vel(B, q2d * B.z) + assert P.a1pt_theory(O, N, B) == -(qd**2) * B.x + qdd * B.y + q2dd * B.z + O.set_vel(N, q2d * B.x) + assert P.a1pt_theory(O, N, B) == ((q2dd - qd**2) * B.x + (q2d * qd + qdd) * B.y + + q2dd * B.z) + + +def test_point_v2pt_theorys(): + q = dynamicsymbols('q') + qd = dynamicsymbols('q', 1) + N = ReferenceFrame('N') + B = N.orientnew('B', 'Axis', [q, N.z]) + O = Point('O') + P = O.locatenew('P', 0) + O.set_vel(N, 0) + assert P.v2pt_theory(O, N, B) == 0 + P = O.locatenew('P', B.x) + assert P.v2pt_theory(O, N, B) == (qd * B.z ^ B.x) + O.set_vel(N, N.x) + assert P.v2pt_theory(O, N, B) == N.x + qd * B.y + + +def test_point_a2pt_theorys(): + q = dynamicsymbols('q') + qd = dynamicsymbols('q', 1) + qdd = dynamicsymbols('q', 2) + N = ReferenceFrame('N') + B = N.orientnew('B', 'Axis', [q, N.z]) + O = Point('O') + P = O.locatenew('P', 0) + O.set_vel(N, 0) + assert P.a2pt_theory(O, N, B) == 0 + P.set_pos(O, B.x) + assert P.a2pt_theory(O, N, B) == (-qd**2) * B.x + (qdd) * B.y + + +def test_point_funcs(): + q, q2 = dynamicsymbols('q q2') + qd, q2d = dynamicsymbols('q q2', 1) + qdd, q2dd = dynamicsymbols('q q2', 2) + N = ReferenceFrame('N') + B = ReferenceFrame('B') + B.set_ang_vel(N, 5 * B.y) + O = Point('O') + P = O.locatenew('P', q * B.x + q2 * B.y) + assert P.pos_from(O) == q * B.x + q2 * B.y + P.set_vel(B, qd * B.x + q2d * B.y) + assert P.vel(B) == qd * B.x + q2d * B.y + O.set_vel(N, 0) + assert O.vel(N) == 0 + assert P.a1pt_theory(O, N, B) == ((-25 * q + qdd) * B.x + (q2dd) * B.y + + (-10 * qd) * B.z) + + B = N.orientnew('B', 'Axis', [q, N.z]) + O = Point('O') + P = O.locatenew('P', 10 * B.x) + O.set_vel(N, 5 * N.x) + assert O.vel(N) == 5 * N.x + assert P.a2pt_theory(O, N, B) == (-10 * qd**2) * B.x + (10 * qdd) * B.y + + B.set_ang_vel(N, 5 * B.y) + O = Point('O') + P = O.locatenew('P', q * B.x + q2 * B.y) + P.set_vel(B, qd * B.x + q2d * B.y) + O.set_vel(N, 0) + assert P.v1pt_theory(O, N, B) == qd * B.x + q2d * B.y - 5 * q * B.z + + +def test_point_pos(): + q = dynamicsymbols('q') + N = ReferenceFrame('N') + B = N.orientnew('B', 'Axis', [q, N.z]) + O = Point('O') + P = O.locatenew('P', 10 * N.x + 5 * B.x) + assert P.pos_from(O) == 10 * N.x + 5 * B.x + Q = P.locatenew('Q', 10 * N.y + 5 * B.y) + assert Q.pos_from(P) == 10 * N.y + 5 * B.y + assert Q.pos_from(O) == 10 * N.x + 10 * N.y + 5 * B.x + 5 * B.y + assert O.pos_from(Q) == -10 * N.x - 10 * N.y - 5 * B.x - 5 * B.y + +def test_point_partial_velocity(): + + N = ReferenceFrame('N') + A = ReferenceFrame('A') + + p = Point('p') + + u1, u2 = dynamicsymbols('u1, u2') + + p.set_vel(N, u1 * A.x + u2 * N.y) + + assert p.partial_velocity(N, u1) == A.x + assert p.partial_velocity(N, u1, u2) == (A.x, N.y) + raises(ValueError, lambda: p.partial_velocity(A, u1)) + +def test_point_vel(): #Basic functionality + q1, q2 = dynamicsymbols('q1 q2') + N = ReferenceFrame('N') + B = ReferenceFrame('B') + Q = Point('Q') + O = Point('O') + Q.set_pos(O, q1 * N.x) + raises(ValueError , lambda: Q.vel(N)) # Velocity of O in N is not defined + O.set_vel(N, q2 * N.y) + assert O.vel(N) == q2 * N.y + raises(ValueError , lambda : O.vel(B)) #Velocity of O is not defined in B + +def test_auto_point_vel(): + t = dynamicsymbols._t + q1, q2 = dynamicsymbols('q1 q2') + N = ReferenceFrame('N') + B = ReferenceFrame('B') + O = Point('O') + Q = Point('Q') + Q.set_pos(O, q1 * N.x) + O.set_vel(N, q2 * N.y) + assert Q.vel(N) == q1.diff(t) * N.x + q2 * N.y # Velocity of Q using O + P1 = Point('P1') + P1.set_pos(O, q1 * B.x) + P2 = Point('P2') + P2.set_pos(P1, q2 * B.z) + raises(ValueError, lambda : P2.vel(B)) # O's velocity is defined in different frame, and no + #point in between has its velocity defined + raises(ValueError, lambda: P2.vel(N)) # Velocity of O not defined in N + +def test_auto_point_vel_multiple_point_path(): + t = dynamicsymbols._t + q1, q2 = dynamicsymbols('q1 q2') + B = ReferenceFrame('B') + P = Point('P') + P.set_vel(B, q1 * B.x) + P1 = Point('P1') + P1.set_pos(P, q2 * B.y) + P1.set_vel(B, q1 * B.z) + P2 = Point('P2') + P2.set_pos(P1, q1 * B.z) + P3 = Point('P3') + P3.set_pos(P2, 10 * q1 * B.y) + assert P3.vel(B) == 10 * q1.diff(t) * B.y + (q1 + q1.diff(t)) * B.z + +def test_auto_vel_dont_overwrite(): + t = dynamicsymbols._t + q1, q2, u1 = dynamicsymbols('q1, q2, u1') + N = ReferenceFrame('N') + P = Point('P1') + P.set_vel(N, u1 * N.x) + P1 = Point('P1') + P1.set_pos(P, q2 * N.y) + assert P1.vel(N) == q2.diff(t) * N.y + u1 * N.x + assert P.vel(N) == u1 * N.x + P1.set_vel(N, u1 * N.z) + assert P1.vel(N) == u1 * N.z + +def test_auto_point_vel_if_tree_has_vel_but_inappropriate_pos_vector(): + q1, q2 = dynamicsymbols('q1 q2') + B = ReferenceFrame('B') + S = ReferenceFrame('S') + P = Point('P') + P.set_vel(B, q1 * B.x) + P1 = Point('P1') + P1.set_pos(P, S.y) + raises(ValueError, lambda : P1.vel(B)) # P1.pos_from(P) can't be expressed in B + raises(ValueError, lambda : P1.vel(S)) # P.vel(S) not defined + +def test_auto_point_vel_shortest_path(): + t = dynamicsymbols._t + q1, q2, u1, u2 = dynamicsymbols('q1 q2 u1 u2') + B = ReferenceFrame('B') + P = Point('P') + P.set_vel(B, u1 * B.x) + P1 = Point('P1') + P1.set_pos(P, q2 * B.y) + P1.set_vel(B, q1 * B.z) + P2 = Point('P2') + P2.set_pos(P1, q1 * B.z) + P3 = Point('P3') + P3.set_pos(P2, 10 * q1 * B.y) + P4 = Point('P4') + P4.set_pos(P3, q1 * B.x) + O = Point('O') + O.set_vel(B, u2 * B.y) + O1 = Point('O1') + O1.set_pos(O, q2 * B.z) + P4.set_pos(O1, q1 * B.x + q2 * B.z) + with warnings.catch_warnings(): #There are two possible paths in this point tree, thus a warning is raised + warnings.simplefilter('error') + with ignore_warnings(UserWarning): + assert P4.vel(B) == q1.diff(t) * B.x + u2 * B.y + 2 * q2.diff(t) * B.z + +def test_auto_point_vel_connected_frames(): + t = dynamicsymbols._t + q, q1, q2, u = dynamicsymbols('q q1 q2 u') + N = ReferenceFrame('N') + B = ReferenceFrame('B') + O = Point('O') + O.set_vel(N, u * N.x) + P = Point('P') + P.set_pos(O, q1 * N.x + q2 * B.y) + raises(ValueError, lambda: P.vel(N)) + N.orient(B, 'Axis', (q, B.x)) + assert P.vel(N) == (u + q1.diff(t)) * N.x + q2.diff(t) * B.y - q2 * q.diff(t) * B.z + +def test_auto_point_vel_multiple_paths_warning_arises(): + q, u = dynamicsymbols('q u') + N = ReferenceFrame('N') + O = Point('O') + P = Point('P') + Q = Point('Q') + R = Point('R') + P.set_vel(N, u * N.x) + Q.set_vel(N, u *N.y) + R.set_vel(N, u * N.z) + O.set_pos(P, q * N.z) + O.set_pos(Q, q * N.y) + O.set_pos(R, q * N.x) + with warnings.catch_warnings(): #There are two possible paths in this point tree, thus a warning is raised + warnings.simplefilter("error") + raises(UserWarning ,lambda: O.vel(N)) + +def test_auto_vel_cyclic_warning_arises(): + P = Point('P') + P1 = Point('P1') + P2 = Point('P2') + P3 = Point('P3') + N = ReferenceFrame('N') + P.set_vel(N, N.x) + P1.set_pos(P, N.x) + P2.set_pos(P1, N.y) + P3.set_pos(P2, N.z) + P1.set_pos(P3, N.x + N.y) + with warnings.catch_warnings(): #The path is cyclic at P1, thus a warning is raised + warnings.simplefilter("error") + raises(UserWarning ,lambda: P2.vel(N)) + +def test_auto_vel_cyclic_warning_msg(): + P = Point('P') + P1 = Point('P1') + P2 = Point('P2') + P3 = Point('P3') + N = ReferenceFrame('N') + P.set_vel(N, N.x) + P1.set_pos(P, N.x) + P2.set_pos(P1, N.y) + P3.set_pos(P2, N.z) + P1.set_pos(P3, N.x + N.y) + with warnings.catch_warnings(record = True) as w: #The path is cyclic at P1, thus a warning is raised + warnings.simplefilter("always") + P2.vel(N) + msg = str(w[-1].message).replace("\n", " ") + assert issubclass(w[-1].category, UserWarning) + assert 'Kinematic loops are defined among the positions of points. This is likely not desired and may cause errors in your calculations.' in msg + +def test_auto_vel_multiple_path_warning_msg(): + N = ReferenceFrame('N') + O = Point('O') + P = Point('P') + Q = Point('Q') + P.set_vel(N, N.x) + Q.set_vel(N, N.y) + O.set_pos(P, N.z) + O.set_pos(Q, N.y) + with warnings.catch_warnings(record = True) as w: #There are two possible paths in this point tree, thus a warning is raised + warnings.simplefilter("always") + O.vel(N) + msg = str(w[-1].message).replace("\n", " ") + assert issubclass(w[-1].category, UserWarning) + assert 'Velocity' in msg + assert 'automatically calculated based on point' in msg + assert 'Velocities from these points are not necessarily the same. This may cause errors in your calculations.' in msg + +def test_auto_vel_derivative(): + q1, q2 = dynamicsymbols('q1:3') + u1, u2 = dynamicsymbols('u1:3', 1) + A = ReferenceFrame('A') + B = ReferenceFrame('B') + C = ReferenceFrame('C') + B.orient_axis(A, A.z, q1) + B.set_ang_vel(A, u1 * A.z) + C.orient_axis(B, B.z, q2) + C.set_ang_vel(B, u2 * B.z) + + Am = Point('Am') + Am.set_vel(A, 0) + Bm = Point('Bm') + Bm.set_pos(Am, B.x) + Bm.set_vel(B, 0) + Bm.set_vel(C, 0) + Cm = Point('Cm') + Cm.set_pos(Bm, C.x) + Cm.set_vel(C, 0) + temp = Cm._vel_dict.copy() + assert Cm.vel(A) == (u1 * B.y + (u1 + u2) * C.y) + Cm._vel_dict = temp + Cm.v2pt_theory(Bm, B, C) + assert Cm.vel(A) == (u1 * B.y + (u1 + u2) * C.y) + +def test_auto_point_acc_zero_vel(): + N = ReferenceFrame('N') + O = Point('O') + O.set_vel(N, 0) + assert O.acc(N) == 0 * N.x + +def test_auto_point_acc_compute_vel(): + t = dynamicsymbols._t + q1 = dynamicsymbols('q1') + N = ReferenceFrame('N') + A = ReferenceFrame('A') + A.orient_axis(N, N.z, q1) + + O = Point('O') + O.set_vel(N, 0) + P = Point('P') + P.set_pos(O, A.x) + assert P.acc(N) == -q1.diff(t) ** 2 * A.x + q1.diff(t, 2) * A.y + +def test_auto_acc_derivative(): + # Tests whether the Point.acc method gives the correct acceleration of the + # end point of two linkages in series, while getting minimal information. + q1, q2 = dynamicsymbols('q1:3') + u1, u2 = dynamicsymbols('q1:3', 1) + v1, v2 = dynamicsymbols('q1:3', 2) + A = ReferenceFrame('A') + B = ReferenceFrame('B') + C = ReferenceFrame('C') + B.orient_axis(A, A.z, q1) + C.orient_axis(B, B.z, q2) + + Am = Point('Am') + Am.set_vel(A, 0) + Bm = Point('Bm') + Bm.set_pos(Am, B.x) + Bm.set_vel(B, 0) + Bm.set_vel(C, 0) + Cm = Point('Cm') + Cm.set_pos(Bm, C.x) + Cm.set_vel(C, 0) + + # Copy dictionaries to later check the calculation using the 2pt_theories + Bm_vel_dict, Cm_vel_dict = Bm._vel_dict.copy(), Cm._vel_dict.copy() + Bm_acc_dict, Cm_acc_dict = Bm._acc_dict.copy(), Cm._acc_dict.copy() + check = -u1 ** 2 * B.x + v1 * B.y - (u1 + u2) ** 2 * C.x + (v1 + v2) * C.y + assert Cm.acc(A) == check + Bm._vel_dict, Cm._vel_dict = Bm_vel_dict, Cm_vel_dict + Bm._acc_dict, Cm._acc_dict = Bm_acc_dict, Cm_acc_dict + Bm.v2pt_theory(Am, A, B) + Cm.v2pt_theory(Bm, A, C) + Bm.a2pt_theory(Am, A, B) + assert Cm.a2pt_theory(Bm, A, C) == check diff --git a/lib/python3.12/site-packages/sympy/physics/vector/tests/test_printing.py b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_printing.py new file mode 100644 index 0000000000000000000000000000000000000000..0930fe9d0bc6e2fcc60b34f37215fdb19e32fdc4 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_printing.py @@ -0,0 +1,353 @@ +# -*- coding: utf-8 -*- + +from sympy.core.function import Function +from sympy.core.symbol import symbols +from sympy.functions.elementary.miscellaneous import sqrt +from sympy.functions.elementary.trigonometric import (asin, cos, sin) +from sympy.physics.vector import ReferenceFrame, dynamicsymbols, Dyadic +from sympy.physics.vector.printing import (VectorLatexPrinter, vpprint, + vsprint, vsstrrepr, vlatex) + + +a, b, c = symbols('a, b, c') +alpha, omega, beta = dynamicsymbols('alpha, omega, beta') + +A = ReferenceFrame('A') +N = ReferenceFrame('N') + +v = a ** 2 * N.x + b * N.y + c * sin(alpha) * N.z +w = alpha * N.x + sin(omega) * N.y + alpha * beta * N.z +ww = alpha * N.x + asin(omega) * N.y - alpha.diff() * beta * N.z +o = a/b * N.x + (c+b)/a * N.y + c**2/b * N.z + +y = a ** 2 * (N.x | N.y) + b * (N.y | N.y) + c * sin(alpha) * (N.z | N.y) +x = alpha * (N.x | N.x) + sin(omega) * (N.y | N.z) + alpha * beta * (N.z | N.x) +xx = N.x | (-N.y - N.z) +xx2 = N.x | (N.y + N.z) + +def ascii_vpretty(expr): + return vpprint(expr, use_unicode=False, wrap_line=False) + + +def unicode_vpretty(expr): + return vpprint(expr, use_unicode=True, wrap_line=False) + + +def test_latex_printer(): + r = Function('r')('t') + assert VectorLatexPrinter().doprint(r ** 2) == "r^{2}" + r2 = Function('r^2')('t') + assert VectorLatexPrinter().doprint(r2.diff()) == r'\dot{r^{2}}' + ra = Function('r__a')('t') + assert VectorLatexPrinter().doprint(ra.diff().diff()) == r'\ddot{r^{a}}' + + +def test_vector_pretty_print(): + + # TODO : The unit vectors should print with subscripts but they just + # print as `n_x` instead of making `x` a subscript with unicode. + + # TODO : The pretty print division does not print correctly here: + # w = alpha * N.x + sin(omega) * N.y + alpha / beta * N.z + + expected = """\ + 2 \n\ +a n_x + b n_y + c*sin(alpha) n_z\ +""" + uexpected = """\ + 2 \n\ +a n_x + b n_y + c⋅sin(α) n_z\ +""" + + assert ascii_vpretty(v) == expected + assert unicode_vpretty(v) == uexpected + + expected = 'alpha n_x + sin(omega) n_y + alpha*beta n_z' + uexpected = 'α n_x + sin(ω) n_y + α⋅β n_z' + + assert ascii_vpretty(w) == expected + assert unicode_vpretty(w) == uexpected + + expected = """\ + 2 \n\ +a b + c c \n\ +- n_x + ----- n_y + -- n_z\n\ +b a b \ +""" + uexpected = """\ + 2 \n\ +a b + c c \n\ +─ n_x + ───── n_y + ── n_z\n\ +b a b \ +""" + + assert ascii_vpretty(o) == expected + assert unicode_vpretty(o) == uexpected + + # https://github.com/sympy/sympy/issues/26731 + assert ascii_vpretty(-A.x) == '-a_x' + assert unicode_vpretty(-A.x) == '-a_x' + + # https://github.com/sympy/sympy/issues/26799 + assert ascii_vpretty(0*A.x) == '0' + assert unicode_vpretty(0*A.x) == '0' + + +def test_vector_latex(): + + a, b, c, d, omega = symbols('a, b, c, d, omega') + + v = (a ** 2 + b / c) * A.x + sqrt(d) * A.y + cos(omega) * A.z + + assert vlatex(v) == (r'(a^{2} + \frac{b}{c})\mathbf{\hat{a}_x} + ' + r'\sqrt{d}\mathbf{\hat{a}_y} + ' + r'\cos{\left(\omega \right)}' + r'\mathbf{\hat{a}_z}') + + theta, omega, alpha, q = dynamicsymbols('theta, omega, alpha, q') + + v = theta * A.x + omega * omega * A.y + (q * alpha) * A.z + + assert vlatex(v) == (r'\theta\mathbf{\hat{a}_x} + ' + r'\omega^{2}\mathbf{\hat{a}_y} + ' + r'\alpha q\mathbf{\hat{a}_z}') + + phi1, phi2, phi3 = dynamicsymbols('phi1, phi2, phi3') + theta1, theta2, theta3 = symbols('theta1, theta2, theta3') + + v = (sin(theta1) * A.x + + cos(phi1) * cos(phi2) * A.y + + cos(theta1 + phi3) * A.z) + + assert vlatex(v) == (r'\sin{\left(\theta_{1} \right)}' + r'\mathbf{\hat{a}_x} + \cos{' + r'\left(\phi_{1} \right)} \cos{' + r'\left(\phi_{2} \right)}\mathbf{\hat{a}_y} + ' + r'\cos{\left(\theta_{1} + ' + r'\phi_{3} \right)}\mathbf{\hat{a}_z}') + + N = ReferenceFrame('N') + + a, b, c, d, omega = symbols('a, b, c, d, omega') + + v = (a ** 2 + b / c) * N.x + sqrt(d) * N.y + cos(omega) * N.z + + expected = (r'(a^{2} + \frac{b}{c})\mathbf{\hat{n}_x} + ' + r'\sqrt{d}\mathbf{\hat{n}_y} + ' + r'\cos{\left(\omega \right)}' + r'\mathbf{\hat{n}_z}') + + assert vlatex(v) == expected + + # Try custom unit vectors. + + N = ReferenceFrame('N', latexs=(r'\hat{i}', r'\hat{j}', r'\hat{k}')) + + v = (a ** 2 + b / c) * N.x + sqrt(d) * N.y + cos(omega) * N.z + + expected = (r'(a^{2} + \frac{b}{c})\hat{i} + ' + r'\sqrt{d}\hat{j} + ' + r'\cos{\left(\omega \right)}\hat{k}') + assert vlatex(v) == expected + + expected = r'\alpha\mathbf{\hat{n}_x} + \operatorname{asin}{\left(\omega ' \ + r'\right)}\mathbf{\hat{n}_y} - \beta \dot{\alpha}\mathbf{\hat{n}_z}' + assert vlatex(ww) == expected + + expected = r'- \mathbf{\hat{n}_x}\otimes \mathbf{\hat{n}_y} - ' \ + r'\mathbf{\hat{n}_x}\otimes \mathbf{\hat{n}_z}' + assert vlatex(xx) == expected + + expected = r'\mathbf{\hat{n}_x}\otimes \mathbf{\hat{n}_y} + ' \ + r'\mathbf{\hat{n}_x}\otimes \mathbf{\hat{n}_z}' + assert vlatex(xx2) == expected + + +def test_vector_latex_arguments(): + assert vlatex(N.x * 3.0, full_prec=False) == r'3.0\mathbf{\hat{n}_x}' + assert vlatex(N.x * 3.0, full_prec=True) == r'3.00000000000000\mathbf{\hat{n}_x}' + + +def test_vector_latex_with_functions(): + + N = ReferenceFrame('N') + + omega, alpha = dynamicsymbols('omega, alpha') + + v = omega.diff() * N.x + + assert vlatex(v) == r'\dot{\omega}\mathbf{\hat{n}_x}' + + v = omega.diff() ** alpha * N.x + + assert vlatex(v) == (r'\dot{\omega}^{\alpha}' + r'\mathbf{\hat{n}_x}') + + +def test_dyadic_pretty_print(): + + expected = """\ + 2 +a n_x|n_y + b n_y|n_y + c*sin(alpha) n_z|n_y\ +""" + + uexpected = """\ + 2 +a n_x⊗n_y + b n_y⊗n_y + c⋅sin(α) n_z⊗n_y\ +""" + assert ascii_vpretty(y) == expected + assert unicode_vpretty(y) == uexpected + + expected = 'alpha n_x|n_x + sin(omega) n_y|n_z + alpha*beta n_z|n_x' + uexpected = 'α n_x⊗n_x + sin(ω) n_y⊗n_z + α⋅β n_z⊗n_x' + assert ascii_vpretty(x) == expected + assert unicode_vpretty(x) == uexpected + + assert ascii_vpretty(Dyadic([])) == '0' + assert unicode_vpretty(Dyadic([])) == '0' + + assert ascii_vpretty(xx) == '- n_x|n_y - n_x|n_z' + assert unicode_vpretty(xx) == '- n_x⊗n_y - n_x⊗n_z' + + assert ascii_vpretty(xx2) == 'n_x|n_y + n_x|n_z' + assert unicode_vpretty(xx2) == 'n_x⊗n_y + n_x⊗n_z' + + +def test_dyadic_latex(): + + expected = (r'a^{2}\mathbf{\hat{n}_x}\otimes \mathbf{\hat{n}_y} + ' + r'b\mathbf{\hat{n}_y}\otimes \mathbf{\hat{n}_y} + ' + r'c \sin{\left(\alpha \right)}' + r'\mathbf{\hat{n}_z}\otimes \mathbf{\hat{n}_y}') + + assert vlatex(y) == expected + + expected = (r'\alpha\mathbf{\hat{n}_x}\otimes \mathbf{\hat{n}_x} + ' + r'\sin{\left(\omega \right)}\mathbf{\hat{n}_y}' + r'\otimes \mathbf{\hat{n}_z} + ' + r'\alpha \beta\mathbf{\hat{n}_z}\otimes \mathbf{\hat{n}_x}') + + assert vlatex(x) == expected + + assert vlatex(Dyadic([])) == '0' + + +def test_dyadic_str(): + assert vsprint(Dyadic([])) == '0' + assert vsprint(y) == 'a**2*(N.x|N.y) + b*(N.y|N.y) + c*sin(alpha)*(N.z|N.y)' + assert vsprint(x) == 'alpha*(N.x|N.x) + sin(omega)*(N.y|N.z) + alpha*beta*(N.z|N.x)' + assert vsprint(ww) == "alpha*N.x + asin(omega)*N.y - beta*alpha'*N.z" + assert vsprint(xx) == '- (N.x|N.y) - (N.x|N.z)' + assert vsprint(xx2) == '(N.x|N.y) + (N.x|N.z)' + + +def test_vlatex(): # vlatex is broken #12078 + from sympy.physics.vector import vlatex + + x = symbols('x') + J = symbols('J') + + f = Function('f') + g = Function('g') + h = Function('h') + + expected = r'J \left(\frac{d}{d x} g{\left(x \right)} - \frac{d}{d x} h{\left(x \right)}\right)' + + expr = J*f(x).diff(x).subs(f(x), g(x)-h(x)) + + assert vlatex(expr) == expected + + +def test_issue_13354(): + """ + Test for proper pretty printing of physics vectors with ADD + instances in arguments. + + Test is exactly the one suggested in the original bug report by + @moorepants. + """ + + a, b, c = symbols('a, b, c') + A = ReferenceFrame('A') + v = a * A.x + b * A.y + c * A.z + w = b * A.x + c * A.y + a * A.z + z = w + v + + expected = """(a + b) a_x + (b + c) a_y + (a + c) a_z""" + + assert ascii_vpretty(z) == expected + + +def test_vector_derivative_printing(): + # First order + v = omega.diff() * N.x + assert unicode_vpretty(v) == 'ω̇ n_x' + assert ascii_vpretty(v) == "omega'(t) n_x" + + # Second order + v = omega.diff().diff() * N.x + + assert vlatex(v) == r'\ddot{\omega}\mathbf{\hat{n}_x}' + assert unicode_vpretty(v) == 'ω̈ n_x' + assert ascii_vpretty(v) == "omega''(t) n_x" + + # Third order + v = omega.diff().diff().diff() * N.x + + assert vlatex(v) == r'\dddot{\omega}\mathbf{\hat{n}_x}' + assert unicode_vpretty(v) == 'ω⃛ n_x' + assert ascii_vpretty(v) == "omega'''(t) n_x" + + # Fourth order + v = omega.diff().diff().diff().diff() * N.x + + assert vlatex(v) == r'\ddddot{\omega}\mathbf{\hat{n}_x}' + assert unicode_vpretty(v) == 'ω⃜ n_x' + assert ascii_vpretty(v) == "omega''''(t) n_x" + + # Fifth order + v = omega.diff().diff().diff().diff().diff() * N.x + + assert vlatex(v) == r'\frac{d^{5}}{d t^{5}} \omega\mathbf{\hat{n}_x}' + expected = '''\ + 5 \n\ +d \n\ +---(omega) n_x\n\ + 5 \n\ +dt \ +''' + uexpected = '''\ + 5 \n\ +d \n\ +───(ω) n_x\n\ + 5 \n\ +dt \ +''' + assert unicode_vpretty(v) == uexpected + assert ascii_vpretty(v) == expected + + +def test_vector_str_printing(): + assert vsprint(w) == 'alpha*N.x + sin(omega)*N.y + alpha*beta*N.z' + assert vsprint(omega.diff() * N.x) == "omega'*N.x" + assert vsstrrepr(w) == 'alpha*N.x + sin(omega)*N.y + alpha*beta*N.z' + + +def test_vector_str_arguments(): + assert vsprint(N.x * 3.0, full_prec=False) == '3.0*N.x' + assert vsprint(N.x * 3.0, full_prec=True) == '3.00000000000000*N.x' + + +def test_issue_14041(): + import sympy.physics.mechanics as me + + A_frame = me.ReferenceFrame('A') + thetad, phid = me.dynamicsymbols('theta, phi', 1) + L = symbols('L') + + assert vlatex(L*(phid + thetad)**2*A_frame.x) == \ + r"L \left(\dot{\phi} + \dot{\theta}\right)^{2}\mathbf{\hat{a}_x}" + assert vlatex((phid + thetad)**2*A_frame.x) == \ + r"\left(\dot{\phi} + \dot{\theta}\right)^{2}\mathbf{\hat{a}_x}" + assert vlatex((phid*thetad)**a*A_frame.x) == \ + r"\left(\dot{\phi} \dot{\theta}\right)^{a}\mathbf{\hat{a}_x}" diff --git a/lib/python3.12/site-packages/sympy/physics/vector/tests/test_vector.py b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_vector.py new file mode 100644 index 0000000000000000000000000000000000000000..2b9c154e60be553228d37eec609dfc23120935ff --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/tests/test_vector.py @@ -0,0 +1,274 @@ +from sympy.core.numbers import (Float, pi) +from sympy.core.symbol import symbols +from sympy.core.sorting import ordered +from sympy.functions.elementary.trigonometric import (cos, sin) +from sympy.matrices.immutable import ImmutableDenseMatrix as Matrix +from sympy.physics.vector import ReferenceFrame, Vector, dynamicsymbols, dot +from sympy.physics.vector.vector import VectorTypeError +from sympy.abc import x, y, z +from sympy.testing.pytest import raises + +A = ReferenceFrame('A') + + +def test_free_dynamicsymbols(): + A, B, C, D = symbols('A, B, C, D', cls=ReferenceFrame) + a, b, c, d, e, f = dynamicsymbols('a, b, c, d, e, f') + B.orient_axis(A, a, A.x) + C.orient_axis(B, b, B.y) + D.orient_axis(C, c, C.x) + + v = d*D.x + e*D.y + f*D.z + + assert set(ordered(v.free_dynamicsymbols(A))) == {a, b, c, d, e, f} + assert set(ordered(v.free_dynamicsymbols(B))) == {b, c, d, e, f} + assert set(ordered(v.free_dynamicsymbols(C))) == {c, d, e, f} + assert set(ordered(v.free_dynamicsymbols(D))) == {d, e, f} + + +def test_Vector(): + assert A.x != A.y + assert A.y != A.z + assert A.z != A.x + + assert A.x + 0 == A.x + + v1 = x*A.x + y*A.y + z*A.z + v2 = x**2*A.x + y**2*A.y + z**2*A.z + v3 = v1 + v2 + v4 = v1 - v2 + + assert isinstance(v1, Vector) + assert dot(v1, A.x) == x + assert dot(v1, A.y) == y + assert dot(v1, A.z) == z + + assert isinstance(v2, Vector) + assert dot(v2, A.x) == x**2 + assert dot(v2, A.y) == y**2 + assert dot(v2, A.z) == z**2 + + assert isinstance(v3, Vector) + # We probably shouldn't be using simplify in dot... + assert dot(v3, A.x) == x**2 + x + assert dot(v3, A.y) == y**2 + y + assert dot(v3, A.z) == z**2 + z + + assert isinstance(v4, Vector) + # We probably shouldn't be using simplify in dot... + assert dot(v4, A.x) == x - x**2 + assert dot(v4, A.y) == y - y**2 + assert dot(v4, A.z) == z - z**2 + + assert v1.to_matrix(A) == Matrix([[x], [y], [z]]) + q = symbols('q') + B = A.orientnew('B', 'Axis', (q, A.x)) + assert v1.to_matrix(B) == Matrix([[x], + [ y * cos(q) + z * sin(q)], + [-y * sin(q) + z * cos(q)]]) + + #Test the separate method + B = ReferenceFrame('B') + v5 = x*A.x + y*A.y + z*B.z + assert Vector(0).separate() == {} + assert v1.separate() == {A: v1} + assert v5.separate() == {A: x*A.x + y*A.y, B: z*B.z} + + #Test the free_symbols property + v6 = x*A.x + y*A.y + z*A.z + assert v6.free_symbols(A) == {x,y,z} + + raises(TypeError, lambda: v3.applyfunc(v1)) + + +def test_Vector_diffs(): + q1, q2, q3, q4 = dynamicsymbols('q1 q2 q3 q4') + q1d, q2d, q3d, q4d = dynamicsymbols('q1 q2 q3 q4', 1) + q1dd, q2dd, q3dd, q4dd = dynamicsymbols('q1 q2 q3 q4', 2) + N = ReferenceFrame('N') + A = N.orientnew('A', 'Axis', [q3, N.z]) + B = A.orientnew('B', 'Axis', [q2, A.x]) + v1 = q2 * A.x + q3 * N.y + v2 = q3 * B.x + v1 + v3 = v1.dt(B) + v4 = v2.dt(B) + v5 = q1*A.x + q2*A.y + q3*A.z + + assert v1.dt(N) == q2d * A.x + q2 * q3d * A.y + q3d * N.y + assert v1.dt(A) == q2d * A.x + q3 * q3d * N.x + q3d * N.y + assert v1.dt(B) == (q2d * A.x + q3 * q3d * N.x + q3d * + N.y - q3 * cos(q3) * q2d * N.z) + assert v2.dt(N) == (q2d * A.x + (q2 + q3) * q3d * A.y + q3d * B.x + q3d * + N.y) + assert v2.dt(A) == q2d * A.x + q3d * B.x + q3 * q3d * N.x + q3d * N.y + assert v2.dt(B) == (q2d * A.x + q3d * B.x + q3 * q3d * N.x + q3d * N.y - + q3 * cos(q3) * q2d * N.z) + assert v3.dt(N) == (q2dd * A.x + q2d * q3d * A.y + (q3d**2 + q3 * q3dd) * + N.x + q3dd * N.y + (q3 * sin(q3) * q2d * q3d - + cos(q3) * q2d * q3d - q3 * cos(q3) * q2dd) * N.z) + assert v3.dt(A) == (q2dd * A.x + (2 * q3d**2 + q3 * q3dd) * N.x + (q3dd - + q3 * q3d**2) * N.y + (q3 * sin(q3) * q2d * q3d - + cos(q3) * q2d * q3d - q3 * cos(q3) * q2dd) * N.z) + assert (v3.dt(B) - (q2dd*A.x - q3*cos(q3)*q2d**2*A.y + (2*q3d**2 + + q3*q3dd)*N.x + (q3dd - q3*q3d**2)*N.y + (2*q3*sin(q3)*q2d*q3d - + 2*cos(q3)*q2d*q3d - q3*cos(q3)*q2dd)*N.z)).express(B).simplify() == 0 + assert v4.dt(N) == (q2dd * A.x + q3d * (q2d + q3d) * A.y + q3dd * B.x + + (q3d**2 + q3 * q3dd) * N.x + q3dd * N.y + (q3 * + sin(q3) * q2d * q3d - cos(q3) * q2d * q3d - q3 * + cos(q3) * q2dd) * N.z) + assert v4.dt(A) == (q2dd * A.x + q3dd * B.x + (2 * q3d**2 + q3 * q3dd) * + N.x + (q3dd - q3 * q3d**2) * N.y + (q3 * sin(q3) * + q2d * q3d - cos(q3) * q2d * q3d - q3 * cos(q3) * + q2dd) * N.z) + assert (v4.dt(B) - (q2dd*A.x - q3*cos(q3)*q2d**2*A.y + q3dd*B.x + + (2*q3d**2 + q3*q3dd)*N.x + (q3dd - q3*q3d**2)*N.y + + (2*q3*sin(q3)*q2d*q3d - 2*cos(q3)*q2d*q3d - + q3*cos(q3)*q2dd)*N.z)).express(B).simplify() == 0 + assert v5.dt(B) == q1d*A.x + (q3*q2d + q2d)*A.y + (-q2*q2d + q3d)*A.z + assert v5.dt(A) == q1d*A.x + q2d*A.y + q3d*A.z + assert v5.dt(N) == (-q2*q3d + q1d)*A.x + (q1*q3d + q2d)*A.y + q3d*A.z + assert v3.diff(q1d, N) == 0 + assert v3.diff(q2d, N) == A.x - q3 * cos(q3) * N.z + assert v3.diff(q3d, N) == q3 * N.x + N.y + assert v3.diff(q1d, A) == 0 + assert v3.diff(q2d, A) == A.x - q3 * cos(q3) * N.z + assert v3.diff(q3d, A) == q3 * N.x + N.y + assert v3.diff(q1d, B) == 0 + assert v3.diff(q2d, B) == A.x - q3 * cos(q3) * N.z + assert v3.diff(q3d, B) == q3 * N.x + N.y + assert v4.diff(q1d, N) == 0 + assert v4.diff(q2d, N) == A.x - q3 * cos(q3) * N.z + assert v4.diff(q3d, N) == B.x + q3 * N.x + N.y + assert v4.diff(q1d, A) == 0 + assert v4.diff(q2d, A) == A.x - q3 * cos(q3) * N.z + assert v4.diff(q3d, A) == B.x + q3 * N.x + N.y + assert v4.diff(q1d, B) == 0 + assert v4.diff(q2d, B) == A.x - q3 * cos(q3) * N.z + assert v4.diff(q3d, B) == B.x + q3 * N.x + N.y + + # diff() should only express vector components in the derivative frame if + # the orientation of the component's frame depends on the variable + v6 = q2**2*N.y + q2**2*A.y + q2**2*B.y + # already expressed in N + n_measy = 2*q2 + # A_C_N does not depend on q2, so don't express in N + a_measy = 2*q2 + # B_C_N depends on q2, so express in N + b_measx = (q2**2*B.y).dot(N.x).diff(q2) + b_measy = (q2**2*B.y).dot(N.y).diff(q2) + b_measz = (q2**2*B.y).dot(N.z).diff(q2) + n_comp, a_comp = v6.diff(q2, N).args + assert len(v6.diff(q2, N).args) == 2 # only N and A parts + assert n_comp[1] == N + assert a_comp[1] == A + assert n_comp[0] == Matrix([b_measx, b_measy + n_measy, b_measz]) + assert a_comp[0] == Matrix([0, a_measy, 0]) + + +def test_vector_var_in_dcm(): + + N = ReferenceFrame('N') + A = ReferenceFrame('A') + B = ReferenceFrame('B') + u1, u2, u3, u4 = dynamicsymbols('u1 u2 u3 u4') + + v = u1 * u2 * A.x + u3 * N.y + u4**2 * N.z + + assert v.diff(u1, N, var_in_dcm=False) == u2 * A.x + assert v.diff(u1, A, var_in_dcm=False) == u2 * A.x + assert v.diff(u3, N, var_in_dcm=False) == N.y + assert v.diff(u3, A, var_in_dcm=False) == N.y + assert v.diff(u3, B, var_in_dcm=False) == N.y + assert v.diff(u4, N, var_in_dcm=False) == 2 * u4 * N.z + + raises(ValueError, lambda: v.diff(u1, N)) + + +def test_vector_simplify(): + x, y, z, k, n, m, w, f, s, A = symbols('x, y, z, k, n, m, w, f, s, A') + N = ReferenceFrame('N') + + test1 = (1 / x + 1 / y) * N.x + assert (test1 & N.x) != (x + y) / (x * y) + test1 = test1.simplify() + assert (test1 & N.x) == (x + y) / (x * y) + + test2 = (A**2 * s**4 / (4 * pi * k * m**3)) * N.x + test2 = test2.simplify() + assert (test2 & N.x) == (A**2 * s**4 / (4 * pi * k * m**3)) + + test3 = ((4 + 4 * x - 2 * (2 + 2 * x)) / (2 + 2 * x)) * N.x + test3 = test3.simplify() + assert (test3 & N.x) == 0 + + test4 = ((-4 * x * y**2 - 2 * y**3 - 2 * x**2 * y) / (x + y)**2) * N.x + test4 = test4.simplify() + assert (test4 & N.x) == -2 * y + + +def test_vector_evalf(): + a, b = symbols('a b') + v = pi * A.x + assert v.evalf(2) == Float('3.1416', 2) * A.x + v = pi * A.x + 5 * a * A.y - b * A.z + assert v.evalf(3) == Float('3.1416', 3) * A.x + Float('5', 3) * a * A.y - b * A.z + assert v.evalf(5, subs={a: 1.234, b:5.8973}) == Float('3.1415926536', 5) * A.x + Float('6.17', 5) * A.y - Float('5.8973', 5) * A.z + + +def test_vector_angle(): + A = ReferenceFrame('A') + v1 = A.x + A.y + v2 = A.z + assert v1.angle_between(v2) == pi/2 + B = ReferenceFrame('B') + B.orient_axis(A, A.x, pi) + v3 = A.x + v4 = B.x + assert v3.angle_between(v4) == 0 + + +def test_vector_xreplace(): + x, y, z = symbols('x y z') + v = x**2 * A.x + x*y * A.y + x*y*z * A.z + assert v.xreplace({x : cos(x)}) == cos(x)**2 * A.x + y*cos(x) * A.y + y*z*cos(x) * A.z + assert v.xreplace({x*y : pi}) == x**2 * A.x + pi * A.y + x*y*z * A.z + assert v.xreplace({x*y*z : 1}) == x**2*A.x + x*y*A.y + A.z + assert v.xreplace({x:1, z:0}) == A.x + y * A.y + raises(TypeError, lambda: v.xreplace()) + raises(TypeError, lambda: v.xreplace([x, y])) + +def test_issue_23366(): + u1 = dynamicsymbols('u1') + N = ReferenceFrame('N') + N_v_A = u1*N.x + raises(VectorTypeError, lambda: N_v_A.diff(N, u1)) + + +def test_vector_outer(): + a, b, c, d, e, f = symbols('a, b, c, d, e, f') + N = ReferenceFrame('N') + v1 = a*N.x + b*N.y + c*N.z + v2 = d*N.x + e*N.y + f*N.z + v1v2 = Matrix([[a*d, a*e, a*f], + [b*d, b*e, b*f], + [c*d, c*e, c*f]]) + assert v1.outer(v2).to_matrix(N) == v1v2 + assert (v1 | v2).to_matrix(N) == v1v2 + v2v1 = Matrix([[d*a, d*b, d*c], + [e*a, e*b, e*c], + [f*a, f*b, f*c]]) + assert v2.outer(v1).to_matrix(N) == v2v1 + assert (v2 | v1).to_matrix(N) == v2v1 + + +def test_overloaded_operators(): + a, b, c, d, e, f = symbols('a, b, c, d, e, f') + N = ReferenceFrame('N') + v1 = a*N.x + b*N.y + c*N.z + v2 = d*N.x + e*N.y + f*N.z + + assert v1 + v2 == v2 + v1 + assert v1 - v2 == -v2 + v1 + assert v1 & v2 == v2 & v1 + assert v1 ^ v2 == v1.cross(v2) + assert v2 ^ v1 == v2.cross(v1) diff --git a/lib/python3.12/site-packages/sympy/physics/vector/vector.py b/lib/python3.12/site-packages/sympy/physics/vector/vector.py new file mode 100644 index 0000000000000000000000000000000000000000..d27f709353b909c1eb4584495e76b91b1a18af66 --- /dev/null +++ b/lib/python3.12/site-packages/sympy/physics/vector/vector.py @@ -0,0 +1,806 @@ +from sympy import (S, sympify, expand, sqrt, Add, zeros, acos, + ImmutableMatrix as Matrix, simplify) +from sympy.simplify.trigsimp import trigsimp +from sympy.printing.defaults import Printable +from sympy.utilities.misc import filldedent +from sympy.core.evalf import EvalfMixin + +from mpmath.libmp.libmpf import prec_to_dps + + +__all__ = ['Vector'] + + +class Vector(Printable, EvalfMixin): + """The class used to define vectors. + + It along with ReferenceFrame are the building blocks of describing a + classical mechanics system in PyDy and sympy.physics.vector. + + Attributes + ========== + + simp : Boolean + Let certain methods use trigsimp on their outputs + + """ + + simp = False + is_number = False + + def __init__(self, inlist): + """This is the constructor for the Vector class. You should not be + calling this, it should only be used by other functions. You should be + treating Vectors like you would with if you were doing the math by + hand, and getting the first 3 from the standard basis vectors from a + ReferenceFrame. + + The only exception is to create a zero vector: + zv = Vector(0) + + """ + + self.args = [] + if inlist == 0: + inlist = [] + if isinstance(inlist, dict): + d = inlist + else: + d = {} + for inp in inlist: + if inp[1] in d: + d[inp[1]] += inp[0] + else: + d[inp[1]] = inp[0] + + for k, v in d.items(): + if v != Matrix([0, 0, 0]): + self.args.append((v, k)) + + @property + def func(self): + """Returns the class Vector. """ + return Vector + + def __hash__(self): + return hash(tuple(self.args)) + + def __add__(self, other): + """The add operator for Vector. """ + if other == 0: + return self + other = _check_vector(other) + return Vector(self.args + other.args) + + def dot(self, other): + """Dot product of two vectors. + + Returns a scalar, the dot product of the two Vectors + + Parameters + ========== + + other : Vector + The Vector which we are dotting with + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, dot + >>> from sympy import symbols + >>> q1 = symbols('q1') + >>> N = ReferenceFrame('N') + >>> dot(N.x, N.x) + 1 + >>> dot(N.x, N.y) + 0 + >>> A = N.orientnew('A', 'Axis', [q1, N.x]) + >>> dot(N.y, A.y) + cos(q1) + + """ + + from sympy.physics.vector.dyadic import Dyadic, _check_dyadic + if isinstance(other, Dyadic): + other = _check_dyadic(other) + ol = Vector(0) + for v in other.args: + ol += v[0] * v[2] * (v[1].dot(self)) + return ol + other = _check_vector(other) + out = S.Zero + for v1 in self.args: + for v2 in other.args: + out += ((v2[0].T) * (v2[1].dcm(v1[1])) * (v1[0]))[0] + if Vector.simp: + return trigsimp(out, recursive=True) + else: + return out + + def __truediv__(self, other): + """This uses mul and inputs self and 1 divided by other. """ + return self.__mul__(S.One / other) + + def __eq__(self, other): + """Tests for equality. + + It is very import to note that this is only as good as the SymPy + equality test; False does not always mean they are not equivalent + Vectors. + If other is 0, and self is empty, returns True. + If other is 0 and self is not empty, returns False. + If none of the above, only accepts other as a Vector. + + """ + + if other == 0: + other = Vector(0) + try: + other = _check_vector(other) + except TypeError: + return False + if (self.args == []) and (other.args == []): + return True + elif (self.args == []) or (other.args == []): + return False + + frame = self.args[0][1] + for v in frame: + if expand((self - other).dot(v)) != 0: + return False + return True + + def __mul__(self, other): + """Multiplies the Vector by a sympifyable expression. + + Parameters + ========== + + other : Sympifyable + The scalar to multiply this Vector with + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> from sympy import Symbol + >>> N = ReferenceFrame('N') + >>> b = Symbol('b') + >>> V = 10 * b * N.x + >>> print(V) + 10*b*N.x + + """ + + newlist = list(self.args) + other = sympify(other) + for i, v in enumerate(newlist): + newlist[i] = (other * newlist[i][0], newlist[i][1]) + return Vector(newlist) + + def __neg__(self): + return self * -1 + + def outer(self, other): + """Outer product between two Vectors. + + A rank increasing operation, which returns a Dyadic from two Vectors + + Parameters + ========== + + other : Vector + The Vector to take the outer product with + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, outer + >>> N = ReferenceFrame('N') + >>> outer(N.x, N.x) + (N.x|N.x) + + """ + + from sympy.physics.vector.dyadic import Dyadic + other = _check_vector(other) + ol = Dyadic(0) + for v in self.args: + for v2 in other.args: + # it looks this way because if we are in the same frame and + # use the enumerate function on the same frame in a nested + # fashion, then bad things happen + ol += Dyadic([(v[0][0] * v2[0][0], v[1].x, v2[1].x)]) + ol += Dyadic([(v[0][0] * v2[0][1], v[1].x, v2[1].y)]) + ol += Dyadic([(v[0][0] * v2[0][2], v[1].x, v2[1].z)]) + ol += Dyadic([(v[0][1] * v2[0][0], v[1].y, v2[1].x)]) + ol += Dyadic([(v[0][1] * v2[0][1], v[1].y, v2[1].y)]) + ol += Dyadic([(v[0][1] * v2[0][2], v[1].y, v2[1].z)]) + ol += Dyadic([(v[0][2] * v2[0][0], v[1].z, v2[1].x)]) + ol += Dyadic([(v[0][2] * v2[0][1], v[1].z, v2[1].y)]) + ol += Dyadic([(v[0][2] * v2[0][2], v[1].z, v2[1].z)]) + return ol + + def _latex(self, printer): + """Latex Printing method. """ + + ar = self.args # just to shorten things + if len(ar) == 0: + return str(0) + ol = [] # output list, to be concatenated to a string + for i, v in enumerate(ar): + for j in 0, 1, 2: + # if the coef of the basis vector is 1, we skip the 1 + if ar[i][0][j] == 1: + ol.append(' + ' + ar[i][1].latex_vecs[j]) + # if the coef of the basis vector is -1, we skip the 1 + elif ar[i][0][j] == -1: + ol.append(' - ' + ar[i][1].latex_vecs[j]) + elif ar[i][0][j] != 0: + # If the coefficient of the basis vector is not 1 or -1; + # also, we might wrap it in parentheses, for readability. + arg_str = printer._print(ar[i][0][j]) + if isinstance(ar[i][0][j], Add): + arg_str = "(%s)" % arg_str + if arg_str[0] == '-': + arg_str = arg_str[1:] + str_start = ' - ' + else: + str_start = ' + ' + ol.append(str_start + arg_str + ar[i][1].latex_vecs[j]) + outstr = ''.join(ol) + if outstr.startswith(' + '): + outstr = outstr[3:] + elif outstr.startswith(' '): + outstr = outstr[1:] + return outstr + + def _pretty(self, printer): + """Pretty Printing method. """ + from sympy.printing.pretty.stringpict import prettyForm + + terms = [] + + def juxtapose(a, b): + pa = printer._print(a) + pb = printer._print(b) + if a.is_Add: + pa = prettyForm(*pa.parens()) + return printer._print_seq([pa, pb], delimiter=' ') + + for M, N in self.args: + for i in range(3): + if M[i] == 0: + continue + elif M[i] == 1: + terms.append(prettyForm(N.pretty_vecs[i])) + elif M[i] == -1: + terms.append(prettyForm("-1") * prettyForm(N.pretty_vecs[i])) + else: + terms.append(juxtapose(M[i], N.pretty_vecs[i])) + + if terms: + pretty_result = prettyForm.__add__(*terms) + else: + pretty_result = prettyForm("0") + + return pretty_result + + def __rsub__(self, other): + return (-1 * self) + other + + def _sympystr(self, printer, order=True): + """Printing method. """ + if not order or len(self.args) == 1: + ar = list(self.args) + elif len(self.args) == 0: + return printer._print(0) + else: + d = {v[1]: v[0] for v in self.args} + keys = sorted(d.keys(), key=lambda x: x.index) + ar = [] + for key in keys: + ar.append((d[key], key)) + ol = [] # output list, to be concatenated to a string + for i, v in enumerate(ar): + for j in 0, 1, 2: + # if the coef of the basis vector is 1, we skip the 1 + if ar[i][0][j] == 1: + ol.append(' + ' + ar[i][1].str_vecs[j]) + # if the coef of the basis vector is -1, we skip the 1 + elif ar[i][0][j] == -1: + ol.append(' - ' + ar[i][1].str_vecs[j]) + elif ar[i][0][j] != 0: + # If the coefficient of the basis vector is not 1 or -1; + # also, we might wrap it in parentheses, for readability. + arg_str = printer._print(ar[i][0][j]) + if isinstance(ar[i][0][j], Add): + arg_str = "(%s)" % arg_str + if arg_str[0] == '-': + arg_str = arg_str[1:] + str_start = ' - ' + else: + str_start = ' + ' + ol.append(str_start + arg_str + '*' + ar[i][1].str_vecs[j]) + outstr = ''.join(ol) + if outstr.startswith(' + '): + outstr = outstr[3:] + elif outstr.startswith(' '): + outstr = outstr[1:] + return outstr + + def __sub__(self, other): + """The subtraction operator. """ + return self.__add__(other * -1) + + def cross(self, other): + """The cross product operator for two Vectors. + + Returns a Vector, expressed in the same ReferenceFrames as self. + + Parameters + ========== + + other : Vector + The Vector which we are crossing with + + Examples + ======== + + >>> from sympy import symbols + >>> from sympy.physics.vector import ReferenceFrame, cross + >>> q1 = symbols('q1') + >>> N = ReferenceFrame('N') + >>> cross(N.x, N.y) + N.z + >>> A = ReferenceFrame('A') + >>> A.orient_axis(N, q1, N.x) + >>> cross(A.x, N.y) + N.z + >>> cross(N.y, A.x) + - sin(q1)*A.y - cos(q1)*A.z + + """ + + from sympy.physics.vector.dyadic import Dyadic, _check_dyadic + if isinstance(other, Dyadic): + other = _check_dyadic(other) + ol = Dyadic(0) + for i, v in enumerate(other.args): + ol += v[0] * ((self.cross(v[1])).outer(v[2])) + return ol + other = _check_vector(other) + if other.args == []: + return Vector(0) + + def _det(mat): + """This is needed as a little method for to find the determinant + of a list in python; needs to work for a 3x3 list. + SymPy's Matrix will not take in Vector, so need a custom function. + You should not be calling this. + + """ + + return (mat[0][0] * (mat[1][1] * mat[2][2] - mat[1][2] * mat[2][1]) + + mat[0][1] * (mat[1][2] * mat[2][0] - mat[1][0] * + mat[2][2]) + mat[0][2] * (mat[1][0] * mat[2][1] - + mat[1][1] * mat[2][0])) + + outlist = [] + ar = other.args # For brevity + for i, v in enumerate(ar): + tempx = v[1].x + tempy = v[1].y + tempz = v[1].z + tempm = ([[tempx, tempy, tempz], + [self.dot(tempx), self.dot(tempy), self.dot(tempz)], + [Vector([ar[i]]).dot(tempx), Vector([ar[i]]).dot(tempy), + Vector([ar[i]]).dot(tempz)]]) + outlist += _det(tempm).args + return Vector(outlist) + + __radd__ = __add__ + __rmul__ = __mul__ + + def separate(self): + """ + The constituents of this vector in different reference frames, + as per its definition. + + Returns a dict mapping each ReferenceFrame to the corresponding + constituent Vector. + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> R1 = ReferenceFrame('R1') + >>> R2 = ReferenceFrame('R2') + >>> v = R1.x + R2.x + >>> v.separate() == {R1: R1.x, R2: R2.x} + True + + """ + + components = {} + for x in self.args: + components[x[1]] = Vector([x]) + return components + + def __and__(self, other): + return self.dot(other) + __and__.__doc__ = dot.__doc__ + __rand__ = __and__ + + def __xor__(self, other): + return self.cross(other) + __xor__.__doc__ = cross.__doc__ + + def __or__(self, other): + return self.outer(other) + __or__.__doc__ = outer.__doc__ + + def diff(self, var, frame, var_in_dcm=True): + """Returns the partial derivative of the vector with respect to a + variable in the provided reference frame. + + Parameters + ========== + var : Symbol + What the partial derivative is taken with respect to. + frame : ReferenceFrame + The reference frame that the partial derivative is taken in. + var_in_dcm : boolean + If true, the differentiation algorithm assumes that the variable + may be present in any of the direction cosine matrices that relate + the frame to the frames of any component of the vector. But if it + is known that the variable is not present in the direction cosine + matrices, false can be set to skip full reexpression in the desired + frame. + + Examples + ======== + + >>> from sympy import Symbol + >>> from sympy.physics.vector import dynamicsymbols, ReferenceFrame + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> t = Symbol('t') + >>> q1 = dynamicsymbols('q1') + >>> N = ReferenceFrame('N') + >>> A = N.orientnew('A', 'Axis', [q1, N.y]) + >>> A.x.diff(t, N) + - sin(q1)*q1'*N.x - cos(q1)*q1'*N.z + >>> A.x.diff(t, N).express(A).simplify() + - q1'*A.z + >>> B = ReferenceFrame('B') + >>> u1, u2 = dynamicsymbols('u1, u2') + >>> v = u1 * A.x + u2 * B.y + >>> v.diff(u2, N, var_in_dcm=False) + B.y + + """ + + from sympy.physics.vector.frame import _check_frame + + _check_frame(frame) + var = sympify(var) + + inlist = [] + + for vector_component in self.args: + measure_number = vector_component[0] + component_frame = vector_component[1] + if component_frame == frame: + inlist += [(measure_number.diff(var), frame)] + else: + # If the direction cosine matrix relating the component frame + # with the derivative frame does not contain the variable. + if not var_in_dcm or (frame.dcm(component_frame).diff(var) == + zeros(3, 3)): + inlist += [(measure_number.diff(var), component_frame)] + else: # else express in the frame + reexp_vec_comp = Vector([vector_component]).express(frame) + deriv = reexp_vec_comp.args[0][0].diff(var) + inlist += Vector([(deriv, frame)]).args + + return Vector(inlist) + + def express(self, otherframe, variables=False): + """ + Returns a Vector equivalent to this one, expressed in otherframe. + Uses the global express method. + + Parameters + ========== + + otherframe : ReferenceFrame + The frame for this Vector to be described in + + variables : boolean + If True, the coordinate symbols(if present) in this Vector + are re-expressed in terms otherframe + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame, dynamicsymbols + >>> from sympy.physics.vector import init_vprinting + >>> init_vprinting(pretty_print=False) + >>> q1 = dynamicsymbols('q1') + >>> N = ReferenceFrame('N') + >>> A = N.orientnew('A', 'Axis', [q1, N.y]) + >>> A.x.express(N) + cos(q1)*N.x - sin(q1)*N.z + + """ + from sympy.physics.vector import express + return express(self, otherframe, variables=variables) + + def to_matrix(self, reference_frame): + """Returns the matrix form of the vector with respect to the given + frame. + + Parameters + ---------- + reference_frame : ReferenceFrame + The reference frame that the rows of the matrix correspond to. + + Returns + ------- + matrix : ImmutableMatrix, shape(3,1) + The matrix that gives the 1D vector. + + Examples + ======== + + >>> from sympy import symbols + >>> from sympy.physics.vector import ReferenceFrame + >>> a, b, c = symbols('a, b, c') + >>> N = ReferenceFrame('N') + >>> vector = a * N.x + b * N.y + c * N.z + >>> vector.to_matrix(N) + Matrix([ + [a], + [b], + [c]]) + >>> beta = symbols('beta') + >>> A = N.orientnew('A', 'Axis', (beta, N.x)) + >>> vector.to_matrix(A) + Matrix([ + [ a], + [ b*cos(beta) + c*sin(beta)], + [-b*sin(beta) + c*cos(beta)]]) + + """ + + return Matrix([self.dot(unit_vec) for unit_vec in + reference_frame]).reshape(3, 1) + + def doit(self, **hints): + """Calls .doit() on each term in the Vector""" + d = {} + for v in self.args: + d[v[1]] = v[0].applyfunc(lambda x: x.doit(**hints)) + return Vector(d) + + def dt(self, otherframe): + """ + Returns a Vector which is the time derivative of + the self Vector, taken in frame otherframe. + + Calls the global time_derivative method + + Parameters + ========== + + otherframe : ReferenceFrame + The frame to calculate the time derivative in + + """ + from sympy.physics.vector import time_derivative + return time_derivative(self, otherframe) + + def simplify(self): + """Returns a simplified Vector.""" + d = {} + for v in self.args: + d[v[1]] = simplify(v[0]) + return Vector(d) + + def subs(self, *args, **kwargs): + """Substitution on the Vector. + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> from sympy import Symbol + >>> N = ReferenceFrame('N') + >>> s = Symbol('s') + >>> a = N.x * s + >>> a.subs({s: 2}) + 2*N.x + + """ + + d = {} + for v in self.args: + d[v[1]] = v[0].subs(*args, **kwargs) + return Vector(d) + + def magnitude(self): + """Returns the magnitude (Euclidean norm) of self. + + Warnings + ======== + + Python ignores the leading negative sign so that might + give wrong results. + ``-A.x.magnitude()`` would be treated as ``-(A.x.magnitude())``, + instead of ``(-A.x).magnitude()``. + + """ + return sqrt(self.dot(self)) + + def normalize(self): + """Returns a Vector of magnitude 1, codirectional with self.""" + return Vector(self.args + []) / self.magnitude() + + def applyfunc(self, f): + """Apply a function to each component of a vector.""" + if not callable(f): + raise TypeError("`f` must be callable.") + + d = {} + for v in self.args: + d[v[1]] = v[0].applyfunc(f) + return Vector(d) + + def angle_between(self, vec): + """ + Returns the smallest angle between Vector 'vec' and self. + + Parameter + ========= + + vec : Vector + The Vector between which angle is needed. + + Examples + ======== + + >>> from sympy.physics.vector import ReferenceFrame + >>> A = ReferenceFrame("A") + >>> v1 = A.x + >>> v2 = A.y + >>> v1.angle_between(v2) + pi/2 + + >>> v3 = A.x + A.y + A.z + >>> v1.angle_between(v3) + acos(sqrt(3)/3) + + Warnings + ======== + + Python ignores the leading negative sign so that might give wrong + results. ``-A.x.angle_between()`` would be treated as + ``-(A.x.angle_between())``, instead of ``(-A.x).angle_between()``. + + """ + + vec1 = self.normalize() + vec2 = vec.normalize() + angle = acos(vec1.dot(vec2)) + return angle + + def free_symbols(self, reference_frame): + """Returns the free symbols in the measure numbers of the vector + expressed in the given reference frame. + + Parameters + ========== + reference_frame : ReferenceFrame + The frame with respect to which the free symbols of the given + vector is to be determined. + + Returns + ======= + set of Symbol + set of symbols present in the measure numbers of + ``reference_frame``. + + """ + + return self.to_matrix(reference_frame).free_symbols + + def free_dynamicsymbols(self, reference_frame): + """Returns the free dynamic symbols (functions of time ``t``) in the + measure numbers of the vector expressed in the given reference frame. + + Parameters + ========== + reference_frame : ReferenceFrame + The frame with respect to which the free dynamic symbols of the + given vector is to be determined. + + Returns + ======= + set + Set of functions of time ``t``, e.g. + ``Function('f')(me.dynamicsymbols._t)``. + + """ + # TODO : Circular dependency if imported at top. Should move + # find_dynamicsymbols into physics.vector.functions. + from sympy.physics.mechanics.functions import find_dynamicsymbols + + return find_dynamicsymbols(self, reference_frame=reference_frame) + + def _eval_evalf(self, prec): + if not self.args: + return self + new_args = [] + dps = prec_to_dps(prec) + for mat, frame in self.args: + new_args.append([mat.evalf(n=dps), frame]) + return Vector(new_args) + + def xreplace(self, rule): + """Replace occurrences of objects within the measure numbers of the + vector. + + Parameters + ========== + + rule : dict-like + Expresses a replacement rule. + + Returns + ======= + + Vector + Result of the replacement. + + Examples + ======== + + >>> from sympy import symbols, pi + >>> from sympy.physics.vector import ReferenceFrame + >>> A = ReferenceFrame('A') + >>> x, y, z = symbols('x y z') + >>> ((1 + x*y) * A.x).xreplace({x: pi}) + (pi*y + 1)*A.x + >>> ((1 + x*y) * A.x).xreplace({x: pi, y: 2}) + (1 + 2*pi)*A.x + + Replacements occur only if an entire node in the expression tree is + matched: + + >>> ((x*y + z) * A.x).xreplace({x*y: pi}) + (z + pi)*A.x + >>> ((x*y*z) * A.x).xreplace({x*y: pi}) + x*y*z*A.x + + """ + + new_args = [] + for mat, frame in self.args: + mat = mat.xreplace(rule) + new_args.append([mat, frame]) + return Vector(new_args) + + +class VectorTypeError(TypeError): + + def __init__(self, other, want): + msg = filldedent("Expected an instance of %s, but received object " + "'%s' of %s." % (type(want), other, type(other))) + super().__init__(msg) + + +def _check_vector(other): + if not isinstance(other, Vector): + raise TypeError('A Vector must be supplied') + return other