Hello Gilles,
Thanks for your reply. The "env -i PATH=..." stuff seems to work!!!
call system("sh -c 'env -i PATH=/usr/lib64/openmpi/bin:/bin mpirun -n 2
hello_world' ")
did produce the expected result with a simple openmi "hello_world" code I
wrote.
I might be harder though with the real third party app I have in mind. And
I realize
getting passed over a job scheduler with this approach might not work at
all...
I have looked at the MPI_Comm_spawn call but I failed to understand how it
could help here. For instance, can I use it to launch an mpi app with the
option "-n 5" ?
Alex
2014-12-12 0:36 GMT-02:00 Gilles Gouaillardet <gilles.gouaillar...@iferc.org
>:
>
> Alex,
>
> can you try something like
> call system(sh -c 'env -i /.../mpirun -np 2 /.../app_name')
>
> -i start with an empty environment
> that being said, you might need to set a few environment variables
> manually :
> env -i PATH=/bin ...
>
> and that being also said, this "trick" could be just a bad idea :
> you might be using a scheduler, and if you empty the environment, the
> scheduler
> will not be aware of the "inside" run.
>
> on top of that, invoking system might fail depending on the interconnect
> you use.
>
> Bottom line, i believe Ralph's reply is still valid, even if five years
> have passed :
> changing your workflow, or using MPI_Comm_spawn is a much better approach.
>
> Cheers,
>
> Gilles
>
> On 2014/12/12 11:22, Alex A. Schmidt wrote:
>
> Dear OpenMPI users,
>
> Regarding to this previous
> post<http://www.open-mpi.org/community/lists/users/2009/06/9560.php>
> <http://www.open-mpi.org/community/lists/users/2009/06/9560.php> from 2009,
> I wonder if the reply
> from Ralph Castain is still valid. My need is similar but quite simpler:
> to make a system call from an openmpi fortran application to run a
> third party openmpi application. I don't need to exchange mpi messages
> with the application. I just need to read the resulting output file
> generated
> by it. I have tried to do the following system call from my fortran openmpi
> code:
>
> call system("sh -c 'mpirun -n 2 app_name")
>
> but I get
>
> **********************************************************
>
> Open MPI does not support recursive calls of mpirun
>
> **********************************************************
>
> Is there a way to make this work?
>
> Best regards,
>
> Alex
>
>
>
>
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