From owner-chemistry ^at^ ccl.net Wed Nov 12 10:56:00 2008
From: "Justin Finnerty justin.finnerty_._uni-oldenburg.de" <owner-chemistry!=!server.ccl.net>
To: CCL
Subject: CCL: MPI
Message-Id: <-38089-081112105429-29440-qFAeJuu0oV0CroGtBJXKvQ!=!server.ccl.net>
X-Original-From: Justin Finnerty <justin.finnerty|,|uni-oldenburg.de>
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Date: Wed, 12 Nov 2008 16:17:08 +0100
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Sent to CCL by: Justin Finnerty [justin.finnerty\a/uni-oldenburg.de]

On Wed, 2008-11-12 at 07:14 -0500, John McKelvey jmmckel:+:gmail.com
wrote:
> 
> Folks,
> 
> I am a newbie as to running parallel under linux, and need to install
> MPI under RHEL4/AMD-64bit.
> 
> Simple question: Where to start?

I would add that it depends on what you want to do. If you are only
writing your own MPI code then look at OpenMPI as it comes with an RPM
specfile for building a set of RPMs. This makes it much easier to manage
in the long-term.

However, while MPI implementations are supposed to be source compatible
they are not object compatible. What this means is that you will have to
install the matching MPI library for each software you use. For example
we have had to install LAM MPI, OpenMPI, MPICH and MPICH2 on our cluster
to support the computational chemistry software we use (eg NWChem, ORCA
etc). (I also strongly recommend the OSC mpiexec program for MPICH and
MPICH2)

Four MPI installations provides a major problem with configuring your
user environment as you can only have _one_ MPI implementation
configured at a time. We solved this using the Modules program, which
allows us to load and unload settings for each MPI and disallows loading
of two simultaneously. You can also use it to configure your chemistry
software, which can then load the required MPI module. (The Modules
program should be part of RHEL4 installation.)

http://www.lam-mpi.org/
http://www.open-mpi.org/
http://www-unix.mcs.anl.gov/mpi/mpich1/
http://www.mcs.anl.gov/research/projects/mpich2/

Cheers
	Justin
> 
-- 
Dr Justin Finnerty
Rm W3-1-165         Ph 49 (441) 798 3726
Carl von Ossietzky Universität Oldenburg