code: def reconstruct(self, D=None):
          
  
          if D is None:
              Df = self.Xf
          else:
              Df = sl.rfftn(D, None, self.cri.axisN)
  
          Sf = np.sum(self.Zf * Df, axis=self.cri.axisM)
          return sl.irfftn(Sf, self.cri.Nv, self.cri.axisN)
docs: Reconstruct representation.