[Users] Cartoon2D and Carpet

[Luca Baiotti]

Hello,

I have a question about CactusNumerical/Cartoon2D.

In the source file ApplyCartoon.c, there is a condition for the grid setup:

if(cctk_gsh[1] != 2*cctk_nghostzones[1]+1)
    {
            CCTK_WARN(0, "Grid size in y direction inappropriate.");
     }

As far as I could tell, this is generally violated in multilevel
Carpet (CarpetRegrid2) runs, with standard settings that determine the
minimum extension of the refined grids, like
Carpet::use_buffer_zones = yes
mol::ode_method		 = rk4

That condition for Cartoon2D can be achieved on the coarsest level by
setting CoordBase::ymax equal to the spacing dy and CoordBase::ymin
equal to -dy. But it cannot be set for refined levels, because
CarpetRegrid2 adds as many points as required for the buffer zones.
Indeed, Carpet adds enough buffer points for its own purposes that
Cartoon2D seems to work fine.

Should the above condition be changed to

if(cctk_gsh[1] >= 2*cctk_nghostzones[1]+1)

?

Yours,
Luca