Newsgroups: comp.parallel.mpi
From: "Andrew Mc.Ghee" <mcghee@sun.mech.uq.oz.au>
Subject: Submitting input streams to MPI jobs on SGI PowerChallenge?
Organization: Mechanical Engineering, University of Queensland
Date: 8 Aug 1996 13:11:22 GMT
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Message-ID: <4ucp1q$k2p@hobyah.cc.uq.oz.au>

I have a simple problem that has been bothering us for a week, and I'm hoping
that someone out there can quickly set us on the right path.
We are presently trying to run an MPI job on an SGI PowerChallenge using the
following command;

/usr/apps/mpi/bin/mpirun -np 4 $HOME/bin/p.x <$HOME/xtube/part/tube.mb
>tube.log

where "mpirun" is the batch file that SGI uses to start MPI programs,
"p.x" is the MPI program (executable)
"tube.mb" is supposed to be the input stream for the program p.x (have we got
this wrong? is tube.mb actually streaming to the batch file mpirun instead???)
and "tube.log" is (obviously) the output stream from the results.

The strange thing is that of the 4 nodes required for this job, node 0 gets the
input stream tube.mb, and reads the data from it fine, but the other nodes (1,2
& 3) all get no input stream (/dev/null ???). Even stranger is that all nodes
do output messages to the log file tube.log

We have imbedded a system("pwd"); call into the p.x executable, and again, it
returns the correct path for node 0, but reports nothing for the other nodes.

Anyone seen something like this, or can they see something simple that we have
left out? I thought there might be some switch or option to specify the input
stream file for the MPI executable (as on the IBM SP2, on which the code runs
fine), but we haven't found anything yet.

Thanks to anyone who can help us out,
regards,
	Andrew Mc.Ghee
	Mechanical Engineering
	University of Queensland


