def test_bdg_initial_direction():
"""This test the number of inital direction."
"""
hsph_updated = HemiSphere.from_sphere(unit_icosahedron).subdivide(2)
vertices = hsph_updated.vertices
bvecs = vertices
bvals = np.ones(len(vertices)) * 1000
bvecs = np.insert(bvecs, 0, np.array([0, 0, 0]), axis=0)
bvals = np.insert(bvals, 0, 0)
gtab = gradient_table(bvals, bvecs)
# test that we get one direction when we have a single tensor
voxel = single_tensor(gtab).reshape([1, 1, 1, -1])
dti_model = dti.TensorModel(gtab)
boot_dg = BootDirectionGetter.from_data(voxel, dti_model, 30, sh_order=6)
initial_direction = boot_dg.initial_direction(np.zeros(3))
npt.assert_equal(len(initial_direction), 1)
npt.assert_allclose(initial_direction[0], [1, 0, 0], atol=0.1)
# test that we get multiple directions when we have a multi-tensor
mevals = np.array([[1.5, 0.4, 0.4], [1.5, 0.4, 0.4]]) * 1e-3
fracs = [60, 40]
voxel, primary_evecs = multi_tensor(gtab, mevals, fractions=fracs,
snr=None)
voxel = voxel.reshape([1, 1, 1, -1])
response = (np.array([0.0015, 0.0004, 0.0004]), 1)
csd_model = ConstrainedSphericalDeconvModel(gtab, response=response,
sh_order=4)
boot_dg = BootDirectionGetter.from_data(voxel, csd_model, 30)
initial_direction = boot_dg.initial_direction(np.zeros(3))
npt.assert_equal(len(initial_direction), 2)
npt.assert_allclose(initial_direction, primary_evecs, atol=0.1)
def test_bdg_get_direction():
"""This tests the direction found by the bootstrap direction getter.
"""
sphere = HemiSphere.from_sphere(unit_icosahedron.subdivide())
two_neighbors = sphere.edges[0]
direction1 = sphere.vertices[two_neighbors[0]]
direction2 = sphere.vertices[two_neighbors[1]]
angle = np.rad2deg(direction1.dot(direction2))
point = np.zeros(3)
prev_direction = direction2.copy()
pmf = np.zeros([1, 1, 1, len(sphere.vertices)])
pmf[:, :, :, two_neighbors[0]] = 1
pmf_gen = SimplePmfGen(pmf)
# test case in which no valid direction is found with default maxdir
boot_dg = BootDirectionGetter(pmf_gen, angle / 2., sphere=sphere)
npt.assert_equal(boot_dg.get_direction(point, prev_direction), 1)
npt.assert_equal(direction2, prev_direction)
# test case in which no valid direction is found with new max attempts
boot_dg = BootDirectionGetter(pmf_gen,
angle / 2.,
sphere=sphere,
max_attempts=3)
npt.assert_equal(boot_dg.get_direction(point, prev_direction), 1)
npt.assert_equal(direction2, prev_direction)
# test case in which a valid direction is found
boot_dg = BootDirectionGetter(pmf_gen,
angle * 2.,
sphere=sphere,
max_attempts=1)
npt.assert_equal(boot_dg.get_direction(point, prev_direction), 0)
npt.assert_equal(direction1, prev_direction)
# test invalid max_attempts parameters
npt.assert_raises(
ValueError, lambda: BootDirectionGetter(
pmf_gen, angle * 2., sphere=sphere, max_attempts=0))
def test_bdg_get_direction():
"""This tests the direction found by the bootstrap direction getter.
"""
sphere = HemiSphere.from_sphere(unit_icosahedron.subdivide())
two_neighbors = sphere.edges[0]
direction1 = sphere.vertices[two_neighbors[0]]
direction2 = sphere.vertices[two_neighbors[1]]
angle = np.rad2deg(direction1.dot(direction2))
point = np.zeros(3)
prev_direction = direction2.copy()
pmf = np.zeros([1, 1, 1, len(sphere.vertices)])
pmf[:, :, :, two_neighbors[0]] = 1
pmf_gen = SimplePmfGen(pmf)
# test case in which no valid direction is found with default maxdir
boot_dg = BootDirectionGetter(pmf_gen, angle / 2., sphere=sphere)
npt.assert_equal(boot_dg.get_direction(point, prev_direction), 1)
npt.assert_equal(direction2, prev_direction)
# test case in which no valid direction is found with new max attempts
boot_dg = BootDirectionGetter(pmf_gen, angle / 2., sphere=sphere,
max_attempts=3)
npt.assert_equal(boot_dg.get_direction(point, prev_direction), 1)
npt.assert_equal(direction2, prev_direction)
# test case in which a valid direction is found
boot_dg = BootDirectionGetter(pmf_gen, angle * 2., sphere=sphere,
max_attempts=1)
npt.assert_equal(boot_dg.get_direction(point, prev_direction), 0)
npt.assert_equal(direction1, prev_direction)
# test invalid max_attempts parameters
npt.assert_raises(
ValueError,
lambda: BootDirectionGetter(pmf_gen, angle * 2., sphere=sphere,
max_attempts=0))