On Thu, Apr 7, 2016 at 2:31 AM, Luc Bourhis <luc_j_bourhis at mac.com> wrote: > > By default, the cctbx will crash on you if NaN’s are produced, not because > of -ffast-math but because of the way we set the FP flags. Do you unset them > in the CCP4? No, I wasn't even aware of it. Cheers Marcin