code: def get_map_offset(self):
          
  
          nfield = 4
          self.map_offset = np.zeros(nfield).astype(int)
          field_size = self.K * np.array([self.n_dim, 1, self.cov_vec_size, 1])
          for i in np.arange(nfield - 1) + 1:
              self.map_offset[i] = self.map_offset[i - 1] + field_size[i - 1]
          return self.map_offset
docs: Compute offset of prior/posterior
  
  
          Returns
          -------
  
          map_offest : 1D array
              The offset to different fields in prior/posterior