def test_make_scattering_matrix():
numpoints = 5
inc_theta, out_theta = scat.make_angles_grid(numpoints)
scattering_matrix = _scattering_function(inc_theta, out_theta)
assert inc_theta.shape == (numpoints, numpoints)
assert out_theta.shape == (numpoints, numpoints)
theta = scat.make_angles(numpoints)
for i in range(numpoints):
for j in range(numpoints):
assert np.allclose(scattering_matrix[i, j],
_scattering_function(theta[j], theta[i]))
assert scattering_matrix.shape == (numpoints, numpoints)
idx = (1, 3)
np.testing.assert_allclose(
scattering_matrix[idx],
_scattering_function(inc_theta[idx], out_theta[idx]))
np.testing.assert_allclose(_scattering_function(np.pi, np.pi),
_scattering_function(-np.pi, -np.pi))
x = 0.1
np.testing.assert_allclose(_scattering_function(np.pi + x, np.pi),
_scattering_function(-np.pi + x, -np.pi))
def test_interpolate_matrix():
numpoints = 5
dtheta = 2 * np.pi / numpoints
inc_theta, out_theta = scat.make_angles_grid(numpoints)
scattering_matrix = _scattering_function(inc_theta, out_theta)
scat_fn = scat.interpolate_matrix(scattering_matrix)
# raise Exception(scattering_matrix)
np.testing.assert_allclose(scat_fn(inc_theta, out_theta),
_scattering_function(inc_theta, out_theta))
# add multiple of 2pi
np.testing.assert_allclose(
scat_fn(inc_theta + 10 * np.pi, out_theta - 6 * np.pi),
_scattering_function(inc_theta, out_theta),
)
# remove last column because edge effect
x = (inc_theta + dtheta / 4)[:, :-1]
y = out_theta[:, :-1]
np.testing.assert_allclose(scat_fn(x, y), _scattering_function(x, y))
# remove last line because edge effect
x = inc_theta[:-1]
y = (out_theta + dtheta / 4)[:-1]
np.testing.assert_allclose(scat_fn(x, y), _scattering_function(x, y))
x = inc_theta[:-1, :-1] + dtheta / 3
y = (out_theta + dtheta / 4)[:-1, :-1]
np.testing.assert_allclose(scat_fn(x, y), _scattering_function(x, y))
def test_scattering_angles_grid():
n = 10
theta = scat.make_angles(n)
inc_theta, out_theta = scat.make_angles_grid(n)
for i in range(n):
for j in range(n):
assert inc_theta[i, j] == theta[j]
assert out_theta[i, j] == theta[i]
def test_scat_data(self, scat_data_obj):
scat_keys = scat.SCAT_KEYS
scat_obj = scat_data_obj # alias
assert scat_obj.frequencies.ndim == 1
assert scat_obj.numfreq == scat_obj.frequencies.shape[0]
numangles = scat_obj.numangles
# asking values at the known values must be the known values
matrices = scat_obj.as_multi_freq_matrices(scat_obj.frequencies,
numangles)
for scat_key in scat_keys:
np.testing.assert_allclose(matrices[scat_key],
scat_obj.orig_matrices[scat_key],
atol=1e-14)
# another way to ask the known values
frequency = scat_obj.frequencies[0]
phi_in, phi_out = scat.make_angles_grid(numangles)
matrices = scat_obj(phi_in, phi_out, frequency)
np.testing.assert_allclose(matrices[scat_key],
scat_obj.orig_matrices[scat_key][0],
atol=1e-14)
# check angle interpolation
phi = phi_in[0]
a, b = 0.25, 0.75
matrices = scat_obj(
[phi[0], phi[1], a * phi[0] + b * phi[1]],
[phi[2], phi[2], phi[2]],
frequency,
)
for scat_key in scat_keys:
val = matrices[scat_key]
np.testing.assert_allclose(a * val[0] + b * val[1], val[2])
# check frequency interpolation
if scat_obj.numfreq == 1:
# This should be the same value all the time
with warnings.catch_warnings():
warnings.filterwarnings("ignore",
category=arim.exceptions.ArimWarning)
funcs = scat_obj.as_freq_angles_funcs()
for scat_key, func in funcs.items():
assert func(2.0, 3.0,
frequency) == func(2.0, 3.0, frequency * 2.0)
assert func(2.0, 3.0,
frequency) == func(2.0, 3.0, frequency / 2.0)
else:
# This should be a linear interpolation
funcs = scat_obj.as_freq_angles_funcs()
for scat_key, func in funcs.items():
x = a * func(2.0, 3.0, scat_obj.frequencies[0]) + b * func(
2.0, 3.0, scat_obj.frequencies[1])
y = func(
2.0, 3.0,
a * scat_obj.frequencies[0] + b * scat_obj.frequencies[1])
np.testing.assert_allclose(x, y)
# extrapolation: there should be not bound error
func(2.0, 3.0, np.min(scat_obj.frequencies) / 2)
func(2.0, 3.0, np.max(scat_obj.frequencies) * 2)
def test_rotate_matrix():
# n = 10
# scat_matrix = np.random.uniform(size=(n, n)) + 1j * np.random.uniform(size=(n, n))
# scat_func = ut.interpolate_matrix(scat_matrix)
n = 72
inc_angles, out_angles = scat.make_angles_grid(n)
scat_matrix = np.exp(-(inc_angles - np.pi / 6)**2 -
(out_angles + np.pi / 4)**2
) + 1j * np.exp(-(inc_angles + np.pi / 2)**2 -
(out_angles - np.pi / 10)**2)
scat_func = scat.interpolate_matrix(scat_matrix)
# rotation of 0°
rotated_scat_matrix = scat.rotate_matrix(scat_matrix, 0.0)
np.testing.assert_allclose(scat_matrix, rotated_scat_matrix, rtol=1e-6)
# rotation of 360°
rotated_scat_matrix = scat.rotate_matrix(scat_matrix, 2 * np.pi)
np.testing.assert_allclose(scat_matrix, rotated_scat_matrix, rtol=1e-6)
# rotation of pi/ 6
# Ensure that S'(theta_1, theta_2) = S(theta_1 - phi, theta_2 - phi)
# No interpolation is involded here, this should be perfectly equal
phi = np.pi / 6
rotated_scat_matrix = scat.rotate_matrix(scat_matrix, phi)
rotated_scat_scat_func = scat.interpolate_matrix(rotated_scat_matrix)
theta_1 = np.linspace(0, 2 * np.pi, n)
theta_2 = np.linspace(0, np.pi, n)
np.testing.assert_allclose(
rotated_scat_scat_func(theta_1, theta_2),
scat_func(theta_1 - phi, theta_2 - phi),
)
# rotation of pi/ 5
# Ensure that S'(theta_1, theta_2) = S(theta_1 - phi, theta_2 - phi)
# Because of interpolation, this is not exactly equal.
phi = np.pi / 5
rotated_scat_matrix = scat.rotate_matrix(scat_matrix, phi)
rotated_scat_scat_func = scat.interpolate_matrix(rotated_scat_matrix)
theta_1 = np.linspace(0, 2 * np.pi, 15)
theta_2 = np.linspace(0, np.pi, 15)
# import matplotlib.pyplot as plt
# plt.figure()
# plt.plot(np.real(rotated_scat_scat_func(theta_1, theta_2)))
# plt.plot(np.real(scat_func(theta_1 - phi, theta_2 - phi)))
# plt.show()
# plt.figure()
# plt.plot(np.imag(rotated_scat_scat_func(theta_1, theta_2)))
# plt.plot(np.imag(scat_func(theta_1 - phi, theta_2 - phi)))
# plt.show()
np.testing.assert_allclose(
rotated_scat_scat_func(theta_1, theta_2),
scat_func(theta_1 - phi, theta_2 - phi),
atol=5e-3,
)
# unrotate
np.testing.assert_allclose(scat.rotate_matrix(rotated_scat_matrix, -phi),
scat_matrix,
rtol=1e-6)
# test rotate_matrices
matrices = dict(LL=scat_matrix, TT=np.ones((10, 10)))
rotated_matrices = scat.rotate_matrices(matrices, np.pi / 6)
assert "LL" in rotated_matrices
assert "TT" in rotated_matrices
