Function test_label_geometry

mne/tests/test_label.py:1227–1260

Test label geometric computations.

(fname, area)

    ],
)
def test_label_geometry(fname, area):
    """Test label geometric computations."""
    pytest.importorskip("nibabel")
    label = read_label(fname, subject="sample")
    got_area = label.compute_area(subjects_dir=subjects_dir)
    assert_allclose(got_area, area, rtol=1e-3)
    # using a sparse label emits a warning
    label_sparse = label.restrict(src_fname)
    assert 0 < len(label_sparse.vertices) < len(label.vertices)
    with pytest.warns(RuntimeWarning, match="No complete triangles"):
        assert label_sparse.compute_area(subjects_dir=subjects_dir) == 0.0
    dist, outside = label.distances_to_outside(subjects_dir=subjects_dir)
    rr, tris = read_surface(subjects_dir / "sample" / "surf" / "lh.white")
    mask = np.zeros(len(rr), bool)
    mask[label.vertices] = 1
    border_mask = np.isin(label.vertices, _mesh_borders(tris, mask))
    # The distances of the border vertices is smaller than that of non-border
    lo, mi, hi = np.percentile(dist[border_mask], (0, 50, 100))
    assert 0.1e-3 < lo < 0.5e-3 < mi < 1.0e-3 < hi < 2.0e-3
    lo, mi, hi = np.percentile(dist[~border_mask], (0, 50, 100))
    assert 0.5e-3 < lo < 1.0e-3 < mi < 9.0e-3 < hi < 25e-3
    # check that the distances are close but uniformly <= than euclidean
    assert not np.isin(outside, label.vertices).any()
    border_dist = dist[border_mask]
    border_euc = 1e-3 * np.linalg.norm(
        rr[label.vertices[border_mask]] - rr[outside[border_mask]], axis=1
    )
    assert_allclose(border_dist, border_euc, atol=1e-4)
    inside_dist = dist[~border_mask]
    inside_euc = 1e-3 * np.linalg.norm(
        rr[label.vertices[~border_mask]] - rr[outside[~border_mask]], axis=1
    )
    assert_array_less(inside_euc, inside_dist)
    assert_array_less(0.25 * inside_dist, inside_euc)