text: import tensorflow as tf
  import numpy as np
  from tf_interpolate import three_nn, three_interpolate
  
  
  class GroupPointTest(tf.test.TestCase):
      def test(self):
          pass
  
      def test_grad(self):
          with self.test_session():
              points = tf.constant(np.random.random((1, 8, 16)).astype('float32'))
              print(points)
              xyz1 = tf.constant(np.random.random((1, 128, 3)).astype('float32'))
              xyz2 = tf.constant(np.random.random((1, 8, 3)).astype('float32'))
              dist, idx = three_nn(xyz1, xyz2)
              weight = tf.ones_like(dist) / 3.0
              interpolated_points = three_interpolate(points, idx, weight)
              print(interpolated_points)
              err = tf.test.compute_gradient_error(points, (1, 8, 16), interpolated_points, (1, 128, 16))
              print(err)
              self.assertLess(err, 1e-4)
  
  
  if __name__ == '__main__':
      tf.test.main()
  