code: def lambda2nu(lambda_):
      """
      Convert wavelength to optical frequency
  
      Parameters
      ----------
      lambda_ : array_like
          Wavelength(s) to be converted.
  
      Returns
      -------
      nu : float or array of floats
          Equivalent optical frequency.
  
      Notes
      -----
      Computes ``nu = c / lambda`` where c = 299792458.0, i.e., the
      (vacuum) speed of light in meters/second.
  
      Examples
      --------
      >>> from scipy.constants import lambda2nu, speed_of_light
      >>> lambda2nu(np.array((1, speed_of_light)))
      array([  2.99792458e+08,   1.00000000e+00])
  
      """
      return c / _np.asanyarray(lambda_)
  
imports: import math
  from .codata import value
  import numpy
label_desc: Use image node_id 2 for calling a global function with example usage: lambda2nu(lambda_) and returns: unknown