Re: [f2py] OpenMP - again

Here follows a solution when using setup.py file.
So, create a setup.py file containing

#!/usr/bin/env python
def configuration(parent_package='',top_path=None):
    from numpy.distutils.misc_util import Configuration
    config = Configuration(None,parent_package,top_path)
    config.add_extension('wrapper',
                         ['fortranmodule.f95','wrapper.f95'],
                         libraries = ['gomp','blas'],
                         library_dirs = ['/opt/local/lib/gcc44'],
                         f2py_options = [],
                         define_macros = [('F2PY_REPORT_ON_ARRAY_COPY','1')],
                         extra_link_args = ['-fopenmp']
                         )

    return config

if __name__ == "__main__":
    from numpy.distutils.core import setup
    setup(configuration=configuration)
#eof

and then run

python setup.py build_ext --inplace --fcompiler=gnu95

HTH,
Pearu



On Sat, Sep 4, 2010 at 4:24 PM, Pearu Peterson <[email protected]> wrote:
> On Sat, Sep 4, 2010 at 2:51 PM, Paul Anton Letnes
> <[email protected]> wrote:
>> Hi again!
>>
>> On 4. sep. 2010, at 12.30, Pearu Peterson wrote:
>>
>>> Hi!
>>>
>>> On Sat, Sep 4, 2010 at 12:31 PM, Paul Anton Letnes
>>> <[email protected]> wrote:
>>>> Dear f2py fans.
>>>>
>>>> I finally got an OpenMP example up and running. It even gives a decent speedup (1.8-ish) on my 2-core laptop! The only disadvantage is that I have not managed to pass the "-fopenmp" flag to the final compile-and-link command, meaning that if I simply run "make" (Makefile included, of course) the resulting python module is not linked to libopenmp. I managed to fix this by manually copying the final build command and adding the "-fopenmp" flag by hand - see detailed instructions in the Makefile.
>>>>
>>>> Can anyone please tell me how I can "automagically" get the -fopenmp flag into the final build command? I believe that will make this example more complete. Also, feel free to suggest improvements to this example!
>>>
>>> Isn't -fopenmp the flag for the compiler, not for the linker?
>>> f2py has --opt, --f90flags, and --f77flags switches that can be used for
>>> specifying extra options to fortran compiler. Note that when
>>> using these switches then their default values defined
>>> by numpy.distutils.fcompiler will be overwritten. So, always
>>> remember specifying these default values in the switches
>>> as some of them might be required. Redefining --opt might
>>> be the safest way as then one would loose only optimization
>>> flags.
>>
>> As far as I understand, -fopenmp includes -lgomp or similar flag which will tell the compiler to link to the OpenMP library. From my experience, it makes no difference if you include -lgomp or -fopenmp, as long as one of them are present, in the last (linking) stage.
>>
>> I have tried setting --opt='-fopenmp' but that does not help, either. I just want to insert that flag into the final linking stage, because it demonstrably helps. I do not, however, understand why setting --f90flags or --opt does not help?
>
> These switches are used for compilation, not for linkage. I'll look
> into how to add flags to linking command. Afaik, distutils does not
> have switches for that. Specifying LDFLAGS might help, though.
>
> Pearu
>