How can I force Matlab system command to use a different mpiexec than its own?

I have to run another program from Matlab, which however has a parallel environment and thus uses the mpiexec. However, even though I installed Microsoft Open MPI, when I check which mpiexec will be used when running my program with the Matlab system command I get this:

[~,cmd] = system('where mpiexec')
cmd =
C:\Program Files\MATLAB\R2016b\bin\win64\mpiexec.exe
C:\Program Files\Microsoft MPI\Bin\mpiexec.exe

which means Matlab prioritizes its own mpiexec over Microsoft's. However I get errors with the one from Matlab, so I need the other one. I see when I check the path variable with getenv('PATH') there is no Matlab in the path variable, however using

    [~,cmd] = system('echo %PATH%')
    cmd = 
    C:\Program Files\MATLAB\R2016b\bin\win64;C:\Program Files\Microsoft MPI\Bin\;.....

clearly shows that Matlab adds itself to the path once it is opening the shell... So how can I force Matlab system command to not add itself or at least to use the other mpiexec?

Thanks!

[Andrea Michelotti]

Hi,

I had the same issue and I tried many cmd lines trying to execute mpiexec in the right way.

At the end, I just copied mpiexec.exe from Microsoft MPI folder into my MATLAB one and it worked fine.

Answer 1

[Marcel Beining]

Well, I found some workaround myself (searching for the mpi software on the path and temporarily putting it in front of Matlab, see below), but if there is a more elegant solution than this, please report it to me, thanks!

[~,pth] = system('echo %PATH%');
pth = strsplit(pth,';');
mpisoftw = cellfun(@(x) ~isempty(strfind(x,'mpi'))|~isempty(strfind(x,'MPI')),pth);
[~,cmd] = system(sprintf('set PATH=%s;%%PATH%%& where mpiexec',pth{find(mpisoftw,1,'first')}))

cmd =
C:\Program Files\Microsoft MPI\Bin\mpiexec.exe
C:\Program Files\MATLAB\R2016b\bin\win64\mpiexec.exe