Hi,
Suppose I want to set up a grid structure for a BBH evolution using CarpetRegrid2, but ensure that the outer levels never change. What I usually do is set up two box hierarchies centred on the two BHs, but this doesn't guarantee that the outer levels don't change. Instead, I would like to have three hierarchies, one for the outer levels, and two for the BHs, where the latter only contain boxes on the finest levels. I would implement this by not setting the coarser radii for the BH hierarchies, and leaving them at -1.
I was under the impression that this used to be possible, but there is a check in CarpetRegrid2 which prevents this:
-> The radius of refinement level 1 of region 2 is [-1,-1,-1], which is non-negative
I can't see anything in the code which would make this necessary. Is it safe to disable this check?