This is the mail archive of the
fortran@gcc.gnu.org
mailing list for the GNU Fortran project.
Re: -ffast-math and gfortran
> What bothers me about all this discussion on -ffast-math is what is the driver
> for using it? What is the percentage gain in execution speed? Is it really
> that important that a computation gets done in 30 minutes rather than 35 minutes?
>
Jerry,
my group spends on average ~$20k/year to keep our computing cluster up do date.
-ffast-math gives ~10% faster execution for our type of problem
(Monte Carlo simulation of coupled electron-photon transport).
I.e., -ffast-math is worth ~$2000/year to us.
Ivan