| /*---------------------------------------------------------------------------*\ | |
| ========= | | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | |
| \\ / O peration | Website: https://openfoam.org | |
| \\ / A nd | Copyright (C) 2011-2019 OpenFOAM Foundation | |
| \\/ M anipulation | | |
| ------------------------------------------------------------------------------- | |
| License | |
| This file is part of OpenFOAM. | |
| OpenFOAM is free software: you can redistribute it and/or modify it | |
| under the terms of the GNU General Public License as published by | |
| the Free Software Foundation, either version 3 of the License, or | |
| (at your option) any later version. | |
| OpenFOAM is distributed in the hope that it will be useful, but WITHOUT | |
| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| for more details. | |
| You should have received a copy of the GNU General Public License | |
| along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>. | |
| \*---------------------------------------------------------------------------*/ | |
| // * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * // | |
| Foam::adaptiveSolver::adaptiveSolver | |
| ( | |
| const ODESystem& ode, | |
| const dictionary& dict | |
| ) | |
| : | |
| safeScale_(dict.lookupOrDefault<scalar>("safeScale", 0.9)), | |
| alphaInc_(dict.lookupOrDefault<scalar>("alphaIncrease", 0.2)), | |
| alphaDec_(dict.lookupOrDefault<scalar>("alphaDecrease", 0.25)), | |
| minScale_(dict.lookupOrDefault<scalar>("minScale", 0.2)), | |
| maxScale_(dict.lookupOrDefault<scalar>("maxScale", 10)), | |
| dydx0_(ode.nEqns()), | |
| yTemp_(ode.nEqns()) | |
| {} | |
| // * * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * // | |
| bool Foam::adaptiveSolver::resize(const label n) | |
| { | |
| ODESolver::resizeField(dydx0_, n); | |
| ODESolver::resizeField(yTemp_, n); | |
| return true; | |
| } | |
| void Foam::adaptiveSolver::solve | |
| ( | |
| const ODESystem& odes, | |
| scalar& x, | |
| scalarField& y, | |
| const label li, | |
| scalar& dxTry | |
| ) const | |
| { | |
| scalar dx = dxTry; | |
| scalar err = 0.0; | |
| odes.derivatives(x, y, li, dydx0_); | |
| // Loop over solver and adjust step-size as necessary | |
| // to achieve desired error | |
| do | |
| { | |
| // Solve step and provide error estimate | |
| err = solve(x, y, li, dydx0_, dx, yTemp_); | |
| // If error is large reduce dx | |
| if (err > 1) | |
| { | |
| scalar scale = max(safeScale_*pow(err, -alphaDec_), minScale_); | |
| dx *= scale; | |
| if (dx < vSmall) | |
| { | |
| FatalErrorInFunction | |
| << "stepsize underflow" | |
| << exit(FatalError); | |
| } | |
| } | |
| } while (err > 1); | |
| // Update the state | |
| x += dx; | |
| y = yTemp_; | |
| // If the error is small increase the step-size | |
| if (err > pow(maxScale_/safeScale_, -1.0/alphaInc_)) | |
| { | |
| dxTry = | |
| min(max(safeScale_*pow(err, -alphaInc_), minScale_), maxScale_)*dx; | |
| } | |
| else | |
| { | |
| dxTry = safeScale_*maxScale_*dx; | |
| } | |
| } | |
| // ************************************************************************* // | |