Newsgroups: comp.parallel.mpi
From: jafl@cco.caltech.edu (John Lindal)
Subject: Problems reading a file from each MPI process
Organization: California Institute of Technology, Pasadena
Date: 19 Sep 1995 22:22:46 GMT
Message-ID: <43nfrm$cs1@gap.cco.caltech.edu>

I'm running MPI on a network of Sparc's.  Each process needs a lot of
initial data before it can start cranking (after which, they pretty much
crank independently).  It would seem that the easiest way to do this is
to have the main process write a file containing all the data, and then
let each process read this file.  The file is written in the same
directory as the executable, so each Sparc has access to it.

The problem is, it doesn't work.  The worker processes complain that they
can't find the file.  (But when I use system("pwd"), each process prints the
correct directory!)  The problem is also intermittent.

Is there anything in the implementation of MPI that prevents each process
from reading the same file?  (They only open the file for reading.)

How do others handle sending large amounts of data to each worker process?

Thanks for any help.  John Lindal


