mpich2 and python

[Eric A. Borisch]

>From http://www.mcs.anl.gov/research/projects/mpich2/documentation/files/mpich2-1.3.1-installguide.pdf

"
5.2.2 System Requirements

mpd consists of a number of components written in Python. The
configure script should automatically find a version of python in your
PATH that has all the features needed to run mpd. If for some reason
you need to pick a specific version of Python for mpd to use, you can
do so by adding

--with-python=<fullpathname of python interpreter>
"

Looks like the portfile could be set up to provide python25, python26,
etc. variants if needed...

 -Eric


On Sat, Jan 8, 2011 at 1:55 AM, Jason Swails <jason.swails at gmail.com> wrote:
> Hi Joerg,
>
> MPICH2 uses python fairly extensively (the mpirun and mpiexec executables
> are actually just python scripts, as are mpd/mpdboot).  Those developers
> tend to hard-code the python version that they use into their execution
> since they know that works and will be free of any new bugs that may get
> introduced by new versions.  That's the same reason a lot of OS vendors
> strap an old, stripped-out python distribution with their OS: their system
> python utilities work just fine with that version and they're hesitant to
> invest the time to ensure upwards compatibility (especially when Python
> makes a jump like 2.x -> 3.x).  You should not change this to python2.7
> because mpirun/mpiexec are unlikely to work, since the top line stays as:
>
> #!/usr/bin/env /opt/local/bin/python2.5
>
> (I made the change in the Portfile just to make sure)
>
> MPI *stuff* are among the very few things I prefer to do myself (without
> MacPorts, although the python's I add mpi4py to are MP versions), since it
> allows me more flexibility.
>
> You can also install the OpenMPI variant of mpi4py and avoid this issue
> altogether.  I tend to use OpenMPI for my Macs, anyway (though I like mpich2
> better for my Linux boxes, for no special reason, I get similar performance
> out of both).
>
> Happy tidings,
> Jason
>
> On Sat, Jan 8, 2011 at 1:02 AM, Jörg Frauendiener
> <joerg.frauendiener at mac.com> wrote:
>>
>> I have recently come across a somewhat surprising issue:
>> I installed py27-mpi4py which depends on mpich2 and python27. I was
>> surprised to see that mpich2 itself depends on python25. Can someone explain
>> to me why that should be the case? The same is true for py26-mpi4py.
>> I have played around with the Portfile, replacing the references in mpich2
>> to python25 with python27 and it installs perfectly. I have not done any
>> other tests, though. So the question is: is this dependency on python25 a
>> necessity or can it be replaced with python2[67]?
>> Joerg
>>
>>
>>
>> --
>> Jorg Frauendiener         | Tel.: +64-3-479-7770
>> Mathematics & Statistics  | Fax:  +64-3-479-8427
>> University of Otago       | joergf at maths.otago.ac.nz
>> P.O. Box 56               | jorg.frauendiener at otago.ac.nz
>> Dunedin 9010              | http://www.maths.otago.ac.nz
>> Skype: frauendiener
>>
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>
>
>
> --
> Jason M. Swails
> Quantum Theory Project,
> University of Florida
> Ph.D. Graduate Student
> 352-392-4032
>
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