Remove functions and tests for generating random angles by quaternions

Author: junchaoxia

src/aspire/utils/coor_trans.py

@@ -140,71 +140,6 @@ def grid_3d(n, shifted=False, normalized=True):
     }
 
 
-def qrand(nrot, seed=0):
-
-    """
-    Generate a set of quaternions from random normal distribution.
-
-    Each quaternions is a four-elements column vector. Returns a matrix of
-    size 4xn.
-
-    The 3-sphere S^3 in R^4 is a double cover of the rotation group SO(3), SO(3) = RP^3.
-    We identify unit norm quaternions a^2+b^2+c^2+d^2=1 with group elements.
-    The antipodal points (-a,-b,-c,-d) and (a,b,c,d) are identified as the same group elements,
-    so we take a>=0.
-    :param nrot: The number of quaternions for rotations.
-    :param seed: The random seed.
-    :return: An array consists of 4 dimensions quaternions
-    """
-    q = randn(4, nrot, seed=seed)
-    l2_norm = np.sqrt(q[0, :]**2 + q[1, :]**2 + q[2, :]**2 + q[3, :]**2)
-    for i in range(4):
-        q[i, :] = q[i, :] / l2_norm
-
-    for k in range(nrot):
-        if q[0, k] < 0:
-            q[:, k] = -q[:, k]
-
-    return q
-
-
-def q_to_rot(q):
-    """
-    Convert the quaternions into a rotation matrices.
-
-    :param q: Array of quaternions. May be a vector of dimensions 4 x n
-    :return rot_mat: n-by-3-by-3 array of 3x3 rotation matrices.
-    """
-
-    nrot = np.size(q, 1)
-    rot_mat = np.zeros((nrot, 3, 3), dtype=q.dtype)
-
-    rot_mat[:, 0, 0] = q[0, :]**2 + q[1, :]**2 - q[2, :]**2 - q[3, :]**2
-    rot_mat[:, 0, 1] = 2*q[1, :]*q[2, :] - 2*q[0, :]*q[3, :]
-    rot_mat[:, 0, 2] = 2*q[0, :]*q[2, :] + 2*q[1, :]*q[3, :]
-
-    rot_mat[:, 1, 0] = 2*q[1, :]*q[2, :] + 2*q[0, :]*q[3, :]
-    rot_mat[:, 1, 1] = q[0, :]**2 - q[1, :]**2 + q[2, :]**2 - q[3, :]**2
-    rot_mat[:, 1, 2] = -2*q[0, :]*q[1, :] + 2*q[2, :]*q[3, :]
-
-    rot_mat[:, 2, 0] = -2*q[0, :]*q[2, :] + 2*q[1, :]*q[3, :]
-    rot_mat[:, 2, 1] = 2*q[0, :]*q[1, :] + 2*q[2, :]*q[3, :]
-    rot_mat[:, 2, 2] = q[0, :]**2 - q[1, :]**2 - q[2, :]**2 + q[3, :]**2
-    return rot_mat
-
-
-def qrand_rots(nrot, seed=0):
-    """
-    Generate random rotations from quaternions
-
-    :param nrot: The totalArray of quaternions. May be a vector of dimensions 4 x n
-    :return: Array of 3x3 rotation matrices.
-    """
-    qs = qrand(nrot, seed)
-
-    return q_to_rot(qs)
-
-
 def uniform_random_angles(n, seed=None):
     """
     Generate random 3D rotation angles

tests/saved_test_data/rand_quaternions32.npy

@@ -4,11 +4,9 @@
 import numpy as np
 from scipy.spatial.transform import Rotation
 
-from aspire.utils.coor_trans import (grid_2d, grid_3d, q_to_rot, qrand,
-                                     qrand_rots, register_rotations,
+from aspire.utils.coor_trans import (grid_2d, grid_3d, register_rotations,
                                      uniform_random_angles, get_aligned_rotations)
 
-from aspire.utils.coor_trans import grid_3d, uniform_random_angles
 
 DATA_DIR = os.path.join(os.path.dirname(__file__), 'saved_test_data')
 
@@ -36,22 +34,6 @@ def testGrid3d(self):
         self.assertTrue(np.allclose(grid3d['phi'], np.load(os.path.join(DATA_DIR, 'grid3d_8_phi.npy'))))
         self.assertTrue(np.allclose(grid3d['theta'], np.load(os.path.join(DATA_DIR, 'grid3d_8_theta.npy'))))
 
-    def testQrand(self):
-        results = np.load(os.path.join(DATA_DIR, 'rand_quaternions32.npy'))
-        quaternions32 = qrand(32, seed=0)
-        self.assertTrue(np.allclose(results, quaternions32))
-
-    def testQ2Rot(self):
-        results = np.load(os.path.join(DATA_DIR, 'rand_rot_matrices32.npy'))
-        quaternions32 = qrand(32, seed=0)
-        rot_matrices32 = q_to_rot(quaternions32)
-        self.assertTrue(np.allclose(np.moveaxis(results, 2, 0), rot_matrices32))
-
-    def testQrandRots(self):
-        results = np.load(os.path.join(DATA_DIR, 'rand_rot_matrices32.npy'))
-        rot_matrices32 = qrand_rots(32, seed=0)
-        self.assertTrue(np.allclose(np.moveaxis(results, 2, 0), rot_matrices32))
-
     def testRegisterRots(self):
         angles = uniform_random_angles(32, seed=0)
         rots_ref = Rotation.from_euler('ZYZ', angles).as_dcm()