code: def obfn_reg(self):
          
  
          fvf = self.obfn_fvarf()
          rl1 = np.linalg.norm((self.wl1 * self.obfn_gvar()).ravel(), 1)
          rgr = sl.rfl2norm2(np.sqrt(self.GHGf*np.conj(fvf)*fvf), self.cri.Nv,
                             self.cri.axisN)/2.0
          return (self.lmbda*rl1 + self.mu*rgr, rl1, rgr)
docs: Compute regularisation term and contribution to objective
          function.