[MPICH] MPLMD (Multiple Programming Languages Multiple Data)

[William Gropp]

At 03:28 AM 12/17/2005, Koehne Kai wrote:
>Hello,
>
>first of all sorry if the question sounds stupid to you, or if this is not 
>the right place to ask. I am pretty new to MPI in general, and could not 
>find a more specific discussion board ...
>
>The Multiple Programs Multiple Data (MPMD) paradigm is pretty well 
>documented for MPICH. However, I am trying to let multiple programs, 
>written in different programming languages (Java and Python), to 
>communicate. I tried to achieve that with two MPI wrapper libraries, 
>namely mpiJava and pypar.
>
>However, I failed: When combining small Python and Java demo programs in 
>one MPICH procgroup file, the Java programs seem to hang up in the MPI 
>initialization call.
>
>It might be that this problem is specific to the mpiJava wrapper 
>implementation. However, I am a bit astonished that the whole idea of 
>combining MPI programs from different programming languages is hardly ever 
>explained in the literature. Have you had experience with such a setting? 
>And can you recommend me a specific Java wrapper implementation that is 
>known to communicate nicely with other wrapper implementations?

We don't know much about either of these implementations.  The MPI standard 
defined bindings only to C, Fortran, C++, and Fortran 90, and our 
implementations strive to make those work together.  Even that isn't as 
simple as you might think, and in this case, the MPI implementation is 
wrapping everything in the C calls.  I wish we could be more helpful.

Bill


>Regards,
>
>Kai Koehne
>Hasso-Plattner-Instute
>University of Potsdam
>Germany

William Gropp
http://www.mcs.anl.gov/~gropp