boolean scale_by_resolution "scale error estimate by geometric mean of grid spacing"
{
} "no"

  const CCTK_REAL scalefactor = scale_by_resolution ?
    pow(CCTK_DELTA_SPACE(0)*CCTK_DELTA_SPACE(1)*CCTK_DELTA_SPACE(2), 1./3.) :
    1.;

    regrid_error_(p.I) = 1 / fmax(r, CCTK_REAL(1.0e-10));

    regrid_error_(p.I) = scalefactor / fmax(r, CCTK_REAL(1.0e-10));