code: def generate_velocity(n_particles, dimensions, clamp=None):
      """Initialize a velocity vector
  
      Parameters
      ----------
      n_particles : int
          number of particles to be generated in the swarm.
      dimensions: int
          number of dimensions to be generated in the swarm.
      clamp : tuple of floats, optional
          a tuple of size 2 where the first entry is the minimum velocity
          and the second entry is the maximum velocity. It
          sets the limits for velocity clamping. Default is :code:`None`
  
      Returns
      -------
      numpy.ndarray
          velocity matrix of shape (n_particles, dimensions)
      """
      try:
          min_velocity, max_velocity = (
              (0, 1) if clamp is None else clamp
          )
          velocity = (
              max_velocity - min_velocity
          ) * np.random.random_sample(
              size=(n_particles, dimensions)
          ) + min_velocity
      except ValueError:
          msg = "Please check clamp shape: {} != {}"
          rep.logger.exception(msg.format(len(clamp), dimensions))
          raise
      except TypeError:
          msg = "generate_velocity() takes an int for n_particles and dimensions and an array for clamp"
          rep.logger.exception(msg)
          raise
      else:
          return velocity
  
file_path: pyswarms/pyswarms/backend/generators.py
imports: import logging
  import numpy
  from ..utils.reporter import Reporter
  from .swarms import Swarm
label_desc: Use image node_id 3 for calling a global function with example usage: generate_velocity(n_particles, dimensions, clamp) and returns: velocity