// no need of special traversal template<typename MT> V_type fortran_view (MT const &x) { return (x.indexmap().memory_layout_is_c() ? x.transpose() : x);}
// no need of special traversal template <typename MT> V_type fortran_view(MT const &x) { if (x.indexmap().memory_layout_is_c()) return x.transpose(); else return x; }