code: def coeffArraySizeCheck(self):
      
      if prod(self.coeff_matrix.shape) != long(prod(np.array(self.qs.shape,dtype=int64)+2)**2):
        print("Inconsistent size of q0 array and coefficient mattrix")
        print("Exiting.")
        sys.exit()
docs: Make sure that q0 and coefficient array are the right size compared to 
      each other (for finite difference if loading a pre-build coefficient
      array). Otherwise, exit.