ActsTrk::CellTmpl< coordinates_t, NDIM, index_t > Node1 ActsTrk::CellTmpl< coordinates_t, NDIM, index_t >   + CellTmpl() Node2 std::array< coordinates _t, NDIM > + elements   Node2->Node1 +coordinates Node3 index_t     Node3->Node1 +label +srcIndex