Subject: Re: SPMD/MPI on Beowulf Cluster
From: Jim Rosinski (rosinski@bearmtn-e0.cgd.ucar.edu)
Date: Wed Feb 10 1999 - 23:42:27 MST
On Wed, 10 Feb 1999, Mark Gibbas wrote:
> 1) Was the CCM3.6 designed with a specific version of MPI libraries? If
> so what are they, and where can I obtain them?
The message-passing code was built using the MPI library from Argonne
National Lab (www-unix.mcs.anl.gov/mpi), but the coding constructs should be
independent of the particular library used. Only the execution environment
will be distribution-specific. The one such Argonne-specific command I found
in build.noncray_spmd.csh (in CCM3.6.6) is the invocation of "mpirun".
Caveat: I didn't write this script and don't use it so I'm no expert.
> 3) In regards to SPMD/MPI mode in general, are there any specific
> differences from normal mode that must be accounted for when building
> the executable?
Just the contents of Filepath and misc.h required to enable the spmd code
(these should automatically get included in build.noncray_spmd.csh). In
our experience (on SUN and SGI machines) MPI runs give identical answers to
the single-threaded case, though this is not guaranteed.
Regards,
Jim Rosinski
CCM Core Group
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