Hi,

Recently, I found the nancheks of GRHydro show different results sometimes depending on the compilers and codes. As far as I've tested, nans appear only if I use the private thorn GRHydro_RNSID (just a clone of Whisky_RNSID) with XL compilers on AIX machines. I don't see any nans with Intel compilers for the same parfile. Also old Whisky with BSSN_MoL passes the nanchecks safely.

The difference happens actually for somewhat specific situations. It only happens for differentially rotating stars. It disappears if I take a smaller # of refinement levels.

I've tested it applying the IEEE strict floating point options to both compilers (Intel and XL), but the results were same.

Since the problem doesn't happen for Whisky+BSSN_MoL, I think it is not the problem of the private thorn only. My GRHydro_RNSID is basically the same with Whisky_RNSID. Assuming most of you are using the similar thorn, I attached the thornlist and the parfile. I hope you can examine and fix the problem.

Regards,

Hee Il