Re: [f2py] control number of OpenMP threads at runtime

On Sep 17 18:05 -0700, Kevin Mitchell  wrote:
> I would say it's odd that it is not recognizing the environment
> variable. You can always  check that it is visible to fortran via f2py
> with getenv http://darbujan.fzu.cz/cgi-bin/info2www?%28g77%29GetEnv+Intrinsic.
> You could also look at setting the maximum number of threads via
> omplib. If it really isn't visible for some reason, you could always
> 
>  use use(OMP_LIB)
> 
> and then omp_set_num_threads()
> http://gcc.gnu.org/onlinedocs/gcc-4.4.1/libgomp/omp_005fset_005fnum_005fthreads.html#omp_005fset_005fnum_005fthreads

Sorry for the late response.

Well what can I say .. yes it works now. I can't reproduce the case
where it didn't. The extension module reacts to OMP_NUM_THREADS. I also
added an extra input arg to the subroutine which then calls
omp_set_num_threads().

For reference, here are the relevant parts of the Makefile used to build
the extension. Thanks.

-------------------------------------------------------------------------
FILE=flib
FORT=$(FILE).f90
PYF=$(FILE).pyf
EXT_MODULE=_$(FILE)
SO=$(EXT_MODULE).so

F90=gfortran
F90FLAGS=-x f95-cpp-input 
ARCH=-mmmx -m3dnow -msse2 -msse -msse3
#
##F90=ifort
##F90FLAGS=-fpp
##ARCH=-xSSE3

# gfortran
OMP_F90_FLAGS=-fopenmp -D__OPENMP
F2PY_OMP_F90_FLAGS=-lgomp
#
# ifort 
##OMP_F90_FLAGS=-openmp -D__OPENMP 
##F2PY_OMP_F90_FLAGS=-liomp5
#
# no OpenMP
##OMP_F90_FLAGS=
##F2PY_OMP_F90_FLAGS=

F2PY_FLAGS=--opt='-O3' \
			-DF2PY_REPORT_ON_ARRAY_COPY=1 \
			--f90exec=$(F90) \
			--arch="$(ARCH)" \
			--f90flags="$(F90FLAGS) $(OMP_F90_FLAGS)" $(F2PY_OMP_F90_FLAGS)

all: $(SO)

pyf: $(PYF)

$(PYF): $(FORT)
	f2py -h $(PYF) $(FORT) -m $(EXT_MODULE) --overwrite-signature

$(SO): $(PYF) $(FORT)
	f2py -c $(PYF) $(FORT) $(F2PY_FLAGS)
-------------------------------------------------------------------------