Hello Erik, Frank, all,
yes, I would only compute and output the constraints on the coarse level timestep.
The largest issue I see is that e.g. a regular L2 norm over the simulation domain is not very useful. It emphasizes very much the coarse grid, which is very large, and where the boundary conditions might do strange things to the constraints. Similarly, you will need to be careful to exclude the interior of the horizons (see CarpetMask) to avoid looking near the punctures. CarpetMask is not smooth in time, so looking at the time evolution of the constraint norm is then also problematic.
CarpetMask is active and set up (Ian had thankfully already pointed this out).
You might be more happy if you look e.g. at the "isum" or "inorm2" output. This output is not weighted by coordinate volume, but by grid cells, so that the coarse grid is deemphasized.
Ok, I will add isum and inorm2 to the output.Currently I had norm_inf, norm1 and norm2. Really these are only intended to check for obvious errors in the parameter file the make the contraints grow.
Yours, Roland