Hello all, uhh, let me actually read the question. Frank seems to have pointed you to what I assume (have not checked yet) to be the proper documentation that shows what can go wrong. Now for how I worked around the issues myself:
For the symmetric operators branch I use -fp-model precise to the intel compiler eg on zwicky I use the default zwicky machine defintion file in simfactory then add "-fp-model precise" to all CFLAGS/CXXFLAGS/F90FLAGS so that they read: C_OPTIMISE_FLAGS = -O2 -xHost -fp-model precise CXX_OPTIMISE_FLAGS = -O2 -xHost -fp-model precise F77_OPTIMISE_FLAGS = -O2 -xHost -fp-model precise F90_OPTIMISE_FLAGS = -O2 -xHost -fp-model precise for the gnu compiler on bluewaters I had to also disable some optimizations (I don't know why): C_OPTIMISE_FLAGS = -O3 -fno-expensive-optimizations -fno-ipa-cp-clone @Jonah: if you have access to the SXS wiki (say due to Spectre work), you can find this information on https://www.black-holes.org/wiki/center_of_mass_conserving_setup somewhere under the first big table. Yours, Roland On 2015-11-10 22:47, Erik Schnetter wrote: > Roland, I think you have been using such flags. Which flags exactly did you > use? > > -erik > > On Tue, Nov 10, 2015 at 1:45 PM, Frank Loeffler <kn...@cct.lsu.edu> wrote: > >> On Tue, Nov 10, 2015 at 01:38:08PM -0500, Jonah Miller wrote: >>> I am working on developing a modified stencil for the Einstein Toolkit >>> and I am discovering that regression tests pass when I use the GNU >>> compilers but fail when I use the Intel compilers, even with gentle >>> optimization settings such as -O1. I suspect over-zealous optimization. >>> Has anyone encountered this sort of problem before? And if so, does >>> anybody know a good combination of flags that makes the intel compiler >>> more cautious, without sacrificing too much speed? (For example, >>> disabling fast math, which seems to be set to active by default.) >> >> The default for the Intel compiler is non-exact math. Try some of the >> options mentioned here: >> >> >> https://software.intel.com/en-us/articles/consistency-of-floating-point-results-using-the-intel-compiler >> >> How much that influences effective speed likely depends a lot on your >> code. >> >> Frank >> >> >> _______________________________________________ >> Users mailing list >> Users@einsteintoolkit.org >> http://lists.einsteintoolkit.org/mailman/listinfo/users >> >> > > > > > _______________________________________________ > Users mailing list > Users@einsteintoolkit.org > http://lists.einsteintoolkit.org/mailman/listinfo/users > _______________________________________________ Users mailing list Users@einsteintoolkit.org http://lists.einsteintoolkit.org/mailman/listinfo/users
