Hello David,
That makes sense. It will take me a little time to change the source code but I can try it out. I think this is something that should be included in future versions of Cactus so extra code modifications aren’t needed.
Agreed. If you add such code and provide a pull request then I, for my part, would be in favour of including it, even if only for the VECTORISE=no case.
Note that just because the ET compiles does not guarantee that all places in Cactus / Carpet are actually save for the case where CCTK_REAL is "better" than a "double" (they should work fine for CCTK_REAL == float since that has been used in the past). You are mostly in uncharted areas I would say (though others may have used such a setup in the past, I just do not myself recall having seen this being done).
Yours, Roland