def testReorderIndicesByPhiEmpty(self):
with self.session():
indices = geometry.ReorderIndicesByPhi(
tf.constant([1., 0.], tf.float32),
tf.constant(np.zeros([0, 4]), tf.float32)).eval()
self.assertEqual(indices.shape, (0, ))
def testReorderIndicesByPhi(self):
# Picks the anchor point somewhere on the x-y plane.
phi0 = 2 * np.pi / 3
anchor = np.array([np.cos(phi0), np.sin(phi0)])
# Generates points clock-wise relative to the anchor.
pnts = []
n, delta = 16, 0.01
for i in range(n):
phi = phi0 + 1e-6 + 2 * np.pi / n * i
x, y = (1 + i) * np.cos(phi), (1 + i) * np.sin(phi)
pnts += [[y - delta, x - delta, y + delta, x + delta]]
pnts = np.array(pnts)
labels = np.arange(n)
# Randomly permutate the points.
perm = np.random.permutation(n)
pnts = pnts[perm]
labels = labels[perm]
# Uses ReorderIndicesByPhi to figure out how to reshuffle the points to
# recover their original order.
with self.session():
indices = geometry.ReorderIndicesByPhi(anchor, pnts).eval()
print('indices = ', indices)
print('labels = ', labels[indices])
self.assertAllEqual(labels[indices], np.flip(np.arange(n), 0))