     }
     dg::Elliptic<Geometry, Matrix, container>& laplacianM() {return LaplacianM_perp_phi;}
     const container& weights(){return LaplacianM_perp.weights();}
-    const std::vector<container>& inv_weights(){return inv_weights_;}
+    const container& inv_weights(){return LaplacianM_perp.inv_weights();}
     const container& precond(){return LaplacianM_perp.precond();}
   private:
     const eule::Parameters p;
     container temp;    
-    std::vector<container> inv_weights_;
     dg::Elliptic<Geometry, Matrix, container> LaplacianM_perp,LaplacianM_perp_phi;
 
 };

}

template<class Grid, class Matrix, class container>
void Explicit<Grid, Matrix, container>::operator()( std::vector<container>& y, std::vector<container>& yp)
{

    dg::Timer t;

    const std::vector<container>& potential( ) const { return phi;}
    void initializene(const container& y, container& target);

    void operator()(const std::vector<container>& y, std::vector<container>& yp);

    double mass( ) {return mass_;}
    double mass_diffusion( ) {return diff_;}
