code: def eval_objfn(self):
          
  
          g0v = self.obfn_g0(self.obfn_g0var())
          g1v = self.obfn_g1(self.obfn_g1var())
          rgr = sl.rfl2norm2(np.sqrt(self.GHGf * np.conj(self.Xf) * self.Xf),
                             self.cri.Nv, self.cri.axisN)/2.0
          obj = g0v + self.lmbda*g1v + self.mu*rgr
          return (obj, g0v, g1v, rgr)
docs: Compute components of regularisation function as well as total
          contribution to objective function.