def test_sample_locations():
# check positions of samples on toy example, with an affine != identity
# flat horizontal mesh
mesh = flat_mesh(5, 7)
affine = np.diagflat([10, 20, 30, 1])
inv_affine = np.linalg.inv(affine)
# transform vertices to world space
vertices = np.asarray(
resampling.coord_transform(*mesh[0].T, affine=affine)).T
# compute by hand the true offsets in voxel space
# (transformed by affine^-1)
ball_offsets = surface._load_uniform_ball_cloud(10)
ball_offsets = np.asarray(
resampling.coord_transform(*ball_offsets.T, affine=inv_affine)).T
line_offsets = np.zeros((10, 3))
line_offsets[:, 2] = np.linspace(1, -1, 10)
line_offsets = np.asarray(
resampling.coord_transform(*line_offsets.T, affine=inv_affine)).T
# check we get the same locations
for kind, offsets in [('line', line_offsets), ('ball', ball_offsets)]:
locations = surface._sample_locations(
[vertices, mesh[1]], affine, 1., kind=kind, n_points=10)
true_locations = np.asarray([vertex + offsets for vertex in mesh[0]])
assert_array_equal(locations.shape, true_locations.shape)
assert_array_almost_equal(true_locations, locations)
pytest.raises(ValueError, surface._sample_locations,
mesh, affine, 1., kind='bad_kind')
def test_sample_locations():
# check positions of samples on toy example, with an affine != identity
# flat horizontal mesh
mesh = flat_mesh(5, 7)
affine = np.diagflat([10, 20, 30, 1])
inv_affine = np.linalg.inv(affine)
# transform vertices to world space
vertices = np.asarray(
resampling.coord_transform(*mesh[0].T, affine=affine)).T
# compute by hand the true offsets in voxel space
# (transformed by affine^-1)
ball_offsets = surface._load_uniform_ball_cloud(10)
ball_offsets = np.asarray(
resampling.coord_transform(*ball_offsets.T, affine=inv_affine)).T
line_offsets = np.zeros((10, 3))
line_offsets[:, 2] = np.linspace(-1, 1, 10)
line_offsets = np.asarray(
resampling.coord_transform(*line_offsets.T, affine=inv_affine)).T
# check we get the same locations
for kind, offsets in [('line', line_offsets), ('ball', ball_offsets)]:
locations = surface._sample_locations(
[vertices, mesh[1]], affine, 1., kind=kind, n_points=10)
true_locations = np.asarray([vertex + offsets for vertex in mesh[0]])
assert_array_equal(locations.shape, true_locations.shape)
assert_array_almost_equal(true_locations, locations)
assert_raises(ValueError, surface._sample_locations,
mesh, affine, 1., kind='bad_kind')
def test_sample_locations_depth(depth, n_points):
mesh = flat_mesh(5, 7)
radius = 8.
locations = surface._sample_locations(
mesh, np.eye(4), radius, n_points=n_points, depth=depth)
offsets = np.asarray([[0., 0., - z * radius] for z in depth])
expected = np.asarray([vertex + offsets for vertex in mesh[0]])
assert np.allclose(locations, expected)