From help-octave-request at bevo dot che dot wisc dot edu  Thu Feb  1 23:37:37 2001
Subject: Re: MPI
From: Alex Verstak <averstak at vt dot edu>
To: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
cc: help-octave at bevo dot che dot wisc dot edu
Date: Fri, 2 Feb 2001 00:35:49 -0500 (EST)



On Thu, 1 Feb 2001, John W. Eaton wrote:
> On  1-Feb-2001, Alex Verstak <averstak at vt dot edu> wrote:
> | My binding is different from that of Nov 2000.  I didn't do
> | anything fancy; just made .oct files for MPI_Send and company
> | and added three lines to octave.cc for initialization (MPI_Init
> | didn't work from an .oct file).
> 
> Can you explain why not?  What is special about MPI_Init?

It must be called with argc and argv passed to main() before
main() processes them (see MPI standard).  MPICH's mpirun(1),
for example, passes some startup information on the command
line.  MPI_Init strips it off before the application can
see it (similar to the way X libraries eat off --geometry
switches).

Also, the version of MPICH I am using does not like it when
I return from the scope of the function that called MPI_Init.
It just forgets that it has been initialized.  According to
the syscall trace, octave does not unload the .oct file, so
it's probably MPICH's problem...  Doesn't make me feel any
better, though.

=alex



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