On Sat, Nov 6, 2021 at 3:51 PM Mark Adams <mfad...@lbl.gov> wrote: > Yea, that is a bit inscrutable, but I see mumps is the main/only user of > this: > > /* if using PETSc OpenMP support, we only call MUMPS on master ranks. > Before/after the call, we change/restore CPUs the master ranks can run on */ > > And I see _OPENMP is a macro for the release date (yyyymm) of the OMP > version. It's not clear what the v5.0 is ( > https://www.openmp.org/specifications/) > {200505,"2.5"},{200805,"3.0"},{201107,"3.1"},{201307,"4.0"},{201511,"4.5"},{201811,"5.0"},{202011,"5.1"}
On Sat, Nov 6, 2021 at 4:27 PM Junchao Zhang <junchao.zh...@gmail.com> > wrote: > >> >> >> On Sat, Nov 6, 2021 at 5:51 AM Mark Adams <mfad...@lbl.gov> wrote: >> >>> Two questions on OMP: >>> >>> * Can I test for the version of OMP? I want >= 5 and I see this, which >>> looks promising: >>> include/petscsys.h:#elif defined(_OPENMP) && *_OPENMP >= 201307* && >>> !defined(_WIN32) >>> >>> * What is the difference between HAVE_OPENMP and >>> HAVE_OPENMP_SUPPORT. >>> >>> # this is different from HAVE_OPENMP. HAVE_OPENMP_SUPPORT checks if we >> have facilities to support >> # running PETSc in flat-MPI mode and third party libraries in MPI+OpenMP >> hybrid mode >> if self.mpi.found and self.mpi.support_mpi3_shm and self.pthread.found >> and self.hwloc.found: >> # Apple pthread does not provide this functionality >> if self.function.check('pthread_barrier_init', libraries = 'pthread'): >> self.addDefine('HAVE_OPENMP_SUPPORT', 1) >> >> >>> Thanks, >>> Mark >>> >>