def test_vector_to_radial_roundtrip(self):
# round trip some random values.
for i in range(10):
magnitude = np.random.uniform(0., 5.)
direction = np.random.uniform(-np.pi, np.pi)
vector = angles.radial_to_vector(magnitude, direction)
radial = angles.vector_to_radial(*vector)
self.assertAlmostEqual(radial[0], magnitude, 5)
self.assertAlmostEqual(radial[1], direction, 5)
def test_vector_radial(self):
pairs = [((0., 1.), (1., 0.)),
((1., 0.), (1., np.pi / 2)),
((-1., 0.), (1., - np.pi / 2)),
((0., -1.), (1., np.pi)),
((3., 4.), (5., np.arccos(4. / 5.))),
((0., 0.), (0., 0.))]
for vector, radial in pairs:
actual = angles.vector_to_radial(*vector)
# convert from radial to vector and compare
np.testing.assert_almost_equal(actual,
radial,
err_msg=("vector_to_radial\n"
"actual: %s "
"expected: %s "
"args: %s"
% (actual, radial,
vector)))
# now do the same in reverse
actual = angles.radial_to_vector(*radial)
np.testing.assert_almost_equal(actual,
vector,
err_msg=("radial_to_vector\n"
"actual: %s "
"expected: %s "
"args: %s"
% (actual, vector,
radial)))
# now try with direction indicating where the field is flowing from.
actual = angles.vector_to_radial(*vector, orientation="from")
# add pi to the expected value. Note this is done in a way that
# keeps the result in [-pi, pi).
radial = (radial[0], np.mod(radial[1] + 2 * np.pi, 2 * np.pi) - np.pi)
# convert from radial to vector and compare
np.testing.assert_almost_equal(actual,
radial,
err_msg=("vector_to_radial\n"
"actual: %s "
"expected: %s "
"args: %s"
% (actual, radial,
vector)))