// TODO: consider changing CarpetX so that cctk_ash is the size of a vertex
// based grid function rather than a cell based one
#undef CCTK_GFINDEX3D
#define CCTK_GFINDEX3D(cctkGH, i,j,k) ((i) + (j) * (cctk_ash[0] + 1) + (k) * (cctk_ash[0] + 1) * (cctk_ash[1] + 1))