Function test_csp_component_ordering

mne/decoding/tests/test_csp.py:471–491

Test that CSP component ordering works as expected.

()

def test_csp_component_ordering():
    """Test that CSP component ordering works as expected."""
    x, y = deterministic_toy_data(["class_a", "class_b"])

    csp = CSP(component_order="invalid")
    with pytest.raises(ValueError, match="Invalid value"):
        csp.fit(x, y)

    # component_order='alternate' only works with two classes
    csp = CSP(component_order="alternate")
    with pytest.raises(ValueError):
        csp.fit(np.zeros((3, 0, 0)), ["a", "b", "c"])

    p_alt = CSP(component_order="alternate").fit(x, y).patterns_
    p_mut = CSP(component_order="mutual_info").fit(x, y).patterns_

    # This permutation of p_alt and p_mut is explained by the particular
    # eigenvalues of the toy data: [0.06, 0.1,   0.5,  0.8].
    # p_alt arranges them to [0.8, 0.06, 0.5, 0.1]
    # p_mut arranges them to [0.06, 0.1, 0.8, 0.5]
    assert_array_almost_equal(p_alt, p_mut[[2, 0, 3, 1]])


@pytest.mark.filterwarnings("ignore:.*Only one sample available.*")