code: def _h_function(self,h):
          
  
          hh = -1.0 * (h * h) / (self.a * self.a)
          return self.contribution * np.exp(hh)
docs: private method for the gaussian variogram "h" function
  
          Parameters
          ----------
          h : (float or numpy.ndarray)
              distance(s)
  
          Returns
          -------
          h_function : float or numpy.ndarray
              the value of the "h" function implied by the GauVario