[MPICH] Redirecting standard/error io

[Rusty Lusk]

From: "David Minor" <david-m at orbotech.com>
Subject: [MPICH] Redirecting standard/error io
Date: Mon, 26 Dec 2005 10:40:34 +0200

> In mpiexiec, is there a way to direct standard input to /dev/null and/or
> a way to direct standard and error output to a file?
> 
> David Minor
> Orbotech
> 

At least for the mpd version of mpiexec, mpiexec represents the parallel
program in several ways, including handling of stdio.

You can direct stdout in the normal way:

  mpiexec -n 3 cpi > cpi.out

Sometimes it is helpful in this situation to label the output by MPI
rank:

  mpiexec -l -n 3 cpi > cpi.out

Stderr works similaraly, and is kept separate from stdout.

You can redirect stdin as well:

  mpiexec -l -s all -n 3 cat < myfile

or

  mpiexec -l -s all -n 3 cat < /dev/null

The '-s' argument describes which processes get stdin.  By default, it
is just process 0.

Hope this helps.  There is more detail in the User's Guide.

Rusty Lusk