Method Diff

fem/coefficient_matrix.cpp:1017–1022

    }

    shared_ptr<CoefficientFunction> Diff (const CoefficientFunction * var,
                                          shared_ptr<CoefficientFunction> dir) const override
    {
      if (this == var) return dir;
      return SymmetricCF(c1->Diff(var, dir));
    }

    shared_ptr<CoefficientFunction> DiffJacobi (const CoefficientFunction * var, T_DJC & cache) const override
    {