code: def generate_random_unit_vector() -> np.ndarray:
      r"""Generate a random unit vector on the sphere S^2.
  
      Citation: http://mathworld.wolfram.com/SpherePointPicking.html
  
      Pseudocode:
        a. Choose random theta \element [0, 2*pi]
        b. Choose random z \element [-1, 1]
        c. Compute output vector u: (x,y,z) = (sqrt(1-z^2)*cos(theta), sqrt(1-z^2)*sin(theta),z)
  
      Returns
      -------
      u: np.ndarray
          A numpy array of shape `(3,)`. u is an unit vector
      """
      theta = np.random.uniform(low=0.0, high=2 * np.pi)
      z = np.random.uniform(low=-1.0, high=1.0)
      u = np.array(
          [
              np.sqrt(1 - z**2) * np.cos(theta),
              np.sqrt(1 - z**2) * np.sin(theta),
              z,
          ]
      )
      return u
  
file_path: deepchem/deepchem/utils/geometry_utils.py
imports: import numpy
  from scipy.spatial.distance import cdist
  from copy import deepcopy
label_desc: Use image node_id 3 for calling a global function with example usage: generate_random_unit_vector() and returns: u