[Beowulf] which mpi library should I focus on?

[Paul Johnson]

i've not written MPI programs before.  I've written plenty of C and
Java, however, and I think I can learn.  I'm trying to decide whether
to concentrate on OpenMPI or MPICH2 as I get started.  In the
Internet, I find plenty of people who are fiercely devoted to MPICH2,
and I also find plenty of people who say OpenMPI is now the "preferred
application".

I am afraid I will start a flame war between these two sides, but I do
need some advice.  My immediate goal is to write programs that can
parallelize statistical analysis (mostly medium sized calculations
that have to be run 1000s of times from various starting random number
seeds).  Many of the projects that we do will be in R, which has
several packages that can be built for MPI framework (such as SNOW or
such), but the installer must select which MPI library to build those
packages against.

What are the reasons to prefer one or the other?

pj
-- 
Paul E. Johnson
Professor, Political Science
1541 Lilac Lane, Room 504
University of Kansas