.venv/Lib/site-packages/networkx/algorithms/tests/test_graphical.py

import pytest

import networkx as nx


def test_valid_degree_sequence1():
    n = 100
    p = 0.3
    for i in range(10):
        G = nx.erdos_renyi_graph(n, p)
        deg = (d for n, d in G.degree())
        assert nx.is_graphical(deg, method="eg")
        assert nx.is_graphical(deg, method="hh")


def test_valid_degree_sequence2():
    n = 100
    for i in range(10):
        G = nx.barabasi_albert_graph(n, 1)
        deg = (d for n, d in G.degree())
        assert nx.is_graphical(deg, method="eg")
        assert nx.is_graphical(deg, method="hh")


def test_string_input():
    pytest.raises(nx.NetworkXException, nx.is_graphical, [], "foo")
    pytest.raises(nx.NetworkXException, nx.is_graphical, ["red"], "hh")
    pytest.raises(nx.NetworkXException, nx.is_graphical, ["red"], "eg")


def test_non_integer_input():
    pytest.raises(nx.NetworkXException, nx.is_graphical, [72.5], "eg")
    pytest.raises(nx.NetworkXException, nx.is_graphical, [72.5], "hh")


def test_negative_input():
    assert not nx.is_graphical([-1], "hh")
    assert not nx.is_graphical([-1], "eg")


class TestAtlas:
    @classmethod
    def setup_class(cls):
        global atlas
        from networkx.generators import atlas

        cls.GAG = atlas.graph_atlas_g()

    def test_atlas(self):
        for graph in self.GAG:
            deg = (d for n, d in graph.degree())
            assert nx.is_graphical(deg, method="eg")
            assert nx.is_graphical(deg, method="hh")


def test_small_graph_true():
    z = [5, 3, 3, 3, 3, 2, 2, 2, 1, 1, 1]
    assert nx.is_graphical(z, method="hh")
    assert nx.is_graphical(z, method="eg")
    z = [10, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2]
    assert nx.is_graphical(z, method="hh")
    assert nx.is_graphical(z, method="eg")
    z = [1, 1, 1, 1, 1, 2, 2, 2, 3, 4]
    assert nx.is_graphical(z, method="hh")
    assert nx.is_graphical(z, method="eg")


def test_small_graph_false():
    z = [1000, 3, 3, 3, 3, 2, 2, 2, 1, 1, 1]
    assert not nx.is_graphical(z, method="hh")
    assert not nx.is_graphical(z, method="eg")
    z = [6, 5, 4, 4, 2, 1, 1, 1]
    assert not nx.is_graphical(z, method="hh")
    assert not nx.is_graphical(z, method="eg")
    z = [1, 1, 1, 1, 1, 1, 2, 2, 2, 3, 4]
    assert not nx.is_graphical(z, method="hh")
    assert not nx.is_graphical(z, method="eg")


def test_directed_degree_sequence():
    # Test a range of valid directed degree sequences
    n, r = 100, 10
    p = 1.0 / r
    for i in range(r):
        G = nx.erdos_renyi_graph(n, p * (i + 1), None, True)
        din = (d for n, d in G.in_degree())
        dout = (d for n, d in G.out_degree())
        assert nx.is_digraphical(din, dout)


def test_small_directed_sequences():
    dout = [5, 3, 3, 3, 3, 2, 2, 2, 1, 1, 1]
    din = [3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 1]
    assert nx.is_digraphical(din, dout)
    # Test nongraphical directed sequence
    dout = [1000, 3, 3, 3, 3, 2, 2, 2, 1, 1, 1]
    din = [103, 102, 102, 102, 102, 102, 102, 102, 102, 102]
    assert not nx.is_digraphical(din, dout)
    # Test digraphical small sequence
    dout = [1, 1, 1, 1, 1, 2, 2, 2, 3, 4]
    din = [2, 2, 2, 2, 2, 2, 2, 2, 1, 1]
    assert nx.is_digraphical(din, dout)
    # Test nonmatching sum
    din = [2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1]
    assert not nx.is_digraphical(din, dout)
    # Test for negative integer in sequence
    din = [2, 2, 2, -2, 2, 2, 2, 2, 1, 1, 4]
    assert not nx.is_digraphical(din, dout)
    # Test for noninteger
    din = dout = [1, 1, 1.1, 1]
    assert not nx.is_digraphical(din, dout)
    din = dout = [1, 1, "rer", 1]
    assert not nx.is_digraphical(din, dout)


def test_multi_sequence():
    # Test nongraphical multi sequence
    seq = [1000, 3, 3, 3, 3, 2, 2, 2, 1, 1]
    assert not nx.is_multigraphical(seq)
    # Test small graphical multi sequence
    seq = [6, 5, 4, 4, 2, 1, 1, 1]
    assert nx.is_multigraphical(seq)
    # Test for negative integer in sequence
    seq = [6, 5, 4, -4, 2, 1, 1, 1]
    assert not nx.is_multigraphical(seq)
    # Test for sequence with odd sum
    seq = [1, 1, 1, 1, 1, 1, 2, 2, 2, 3, 4]
    assert not nx.is_multigraphical(seq)
    # Test for noninteger
    seq = [1, 1, 1.1, 1]
    assert not nx.is_multigraphical(seq)
    seq = [1, 1, "rer", 1]
    assert not nx.is_multigraphical(seq)


def test_pseudo_sequence():
    # Test small valid pseudo sequence
    seq = [1000, 3, 3, 3, 3, 2, 2, 2, 1, 1]
    assert nx.is_pseudographical(seq)
    # Test for sequence with odd sum
    seq = [1000, 3, 3, 3, 3, 2, 2, 2, 1, 1, 1]
    assert not nx.is_pseudographical(seq)
    # Test for negative integer in sequence
    seq = [1000, 3, 3, 3, 3, 2, 2, -2, 1, 1]
    assert not nx.is_pseudographical(seq)
    # Test for noninteger
    seq = [1, 1, 1.1, 1]
    assert not nx.is_pseudographical(seq)
    seq = [1, 1, "rer", 1]
    assert not nx.is_pseudographical(seq)


def test_numpy_degree_sequence():
    np = pytest.importorskip("numpy")
    ds = np.array([1, 2, 2, 2, 1], dtype=np.int64)
    assert nx.is_graphical(ds, "eg")
    assert nx.is_graphical(ds, "hh")
    ds = np.array([1, 2, 2, 2, 1], dtype=np.float64)
    assert nx.is_graphical(ds, "eg")
    assert nx.is_graphical(ds, "hh")
    ds = np.array([1.1, 2, 2, 2, 1], dtype=np.float64)
    pytest.raises(nx.NetworkXException, nx.is_graphical, ds, "eg")
    pytest.raises(nx.NetworkXException, nx.is_graphical, ds, "hh")