def test_center():
"""Test getting and setting the center."""
sphere = Sphere(1)
assert all(sphere.center == (0, 0, 0))
center = (1, 1, 1)
sphere.center = center
assert all(sphere.center == center)
def test_inertia_tensor(r, center):
sphere = Sphere(r)
assert np.all(sphere.inertia_tensor >= 0)
volume = 4 / 3 * np.pi * r**3
expected = [2 / 5 * volume * r**2] * 3
np.testing.assert_allclose(np.diag(sphere.inertia_tensor), expected)
sphere.center = center
expected = translate_inertia_tensor(center, np.diag(expected), volume)
np.testing.assert_allclose(sphere.inertia_tensor, expected)
def test_form_factor():
"""Validate the form factor of a sphere.
At the moment this is primarily a regression test, and should be expanded for more
rigorous validation.
"""
q = np.array(
[
[0, 0, 0],
[1, 0, 0],
[-1, 0, 0],
[2, 0, 0],
[0, 1, 0],
[0, 0, 1],
[1, 2, 3],
[-2, 4, -5.2],
],
dtype=float,
)
sphere = Sphere(0.5)
np.testing.assert_allclose(
sphere.compute_form_factor_amplitude(q),
[
0.52359878,
0.51062514,
0.51062514,
0.47307465,
0.51062514,
0.51062514,
0.36181941,
0.11702976,
],
atol=1e-7,
)
sphere.center = [1, 1, 1]
np.testing.assert_allclose(
sphere.compute_form_factor_amplitude(q),
[
0.52359878 + 0.0j,
0.27589194 - 0.42967624j,
0.27589194 + 0.42967624j,
-0.19686852 - 0.43016557j,
0.27589194 - 0.42967624j,
0.27589194 - 0.42967624j,
0.34740824 + 0.10109795j,
-0.11683018 - 0.00683151j,
],
atol=1e-7,
)
