def test_stable_rotation_around_z(self):
starting_p = vector_utils.normalized([1, 1, 1])[0]
z_vec = [0, 0, 1]
angle = math.radians(15)
# Check old distance
arc_dist_before = cartesian_utils.cartesian_arc_distance(starting_p, z_vec)
# Rotate starting_p around z
new_p = vector_utils.rotate_about_arbitrary_axis_in_radians(starting_p, z_vec, angle)
# Check new distance
arc_dist_after = cartesian_utils.cartesian_arc_distance(new_p, z_vec)
self.assertEqual(arc_dist_before, arc_dist_after)
def test_arc_dist_same_over_rotation(self):
starting_p = vector_utils.normalized([1, 1, 1])[0]
min_angle = math.radians(15)
max_angle = math.radians(16)
spin_angle = math.radians(50)
# Generate twice.. should be deterministic
near_p = cartesian_utils.rotate_to_vec_in_anulus_in_radians(starting_p, min_angle, min_angle, spin_angle)
far_p = cartesian_utils.rotate_to_vec_in_anulus_in_radians(starting_p, max_angle, max_angle, spin_angle)
first_anulus_arc_width = cartesian_utils.cartesian_arc_distance(near_p, far_p)
# Still same angle between them
min_angle = math.radians(5)
max_angle = math.radians(6)
near_p = cartesian_utils.rotate_to_vec_in_anulus_in_radians(starting_p, min_angle, min_angle, spin_angle)
far_p = cartesian_utils.rotate_to_vec_in_anulus_in_radians(starting_p, max_angle, max_angle, spin_angle)
second_anulus_arc_width = cartesian_utils.cartesian_arc_distance(near_p, far_p)
# Allow some tolerance
self.assertAlmostEqual(first_anulus_arc_width, second_anulus_arc_width)
