void integrate(std::vector< GlobalVector * > const &x, MeshLib::PropertyVector< double > &balance, double const t, MeshLib::Mesh const &bulk_mesh, std::vector< std::size_t > const &active_element_ids, std::function< Eigen::Vector3d(std::size_t const, MathLib::Point3d const &, double const, std::vector< GlobalVector * > const &)> const &getFlux)