On Oct 21, 2008, at 10:37 AM, Adams, Brian M wrote:
We do have some environmental variables that we guarantee to
be "stable" across releases. You could look for
OMPI_COMM_WORLD_SIZE, or OMPI_UNIVERSE_SIZE (there are a
couple of others as well, but any of these would do).
Q: I just wrote a simple C++ program, including mpi.h and getenv to
check for these two variables and compiled with the mpicxx wrapper
(openmpi-1.2.5 as distributed with RHEL5). When running this
program with orterun, these variables come back NULL from the
environment. The same is true if I just orterun a shell script to
dump the environment to a file. Am I making an obvious mistake here?
Crud - forgot you are using the old 1.2 series. No, we don't have any
good variables for you to use there. You might consider updating to
1.3 (beta should come out soon) to get something stable. Otherwise,
you're kinda stuck with the OMPI-internal ones, so you'll have to be
prepared to make a change should anyone try to use it with 1.3 or
higher as we go forward.
If you absolutely have to do this with 1.2, your best bet is probably
OMPI_MCA_universe as the others are even worse (many are gone in 1.3).
Doug is right that we could use an additional command line flag to
indicate MPI runs, but at this point, we're trying to hide that from
the user, such that all they have to do is run the binary vs.
orterun/mpirun the binary and we detect whether it's a serial or
parallel run.
As for parsing the command line $argv[0] before MPI_Init, I don't
think it will help here. While MPICH implementations typically left
args like -p4pg -p4amslave on the command line, I don't see that
coming from OpenMPI-launched jobs.
Really? That doesn't sound right - we don't touch the arguments to
your application. We test that pretty regularly and I have always seen
the args come through.
Can you provide an example of where it isn't?
Ralph
Brian
_______________________________________________
users mailing list
us...@open-mpi.org
http://www.open-mpi.org/mailman/listinfo.cgi/users
