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Subject: Re: [OMPI users] OpenMPI runtime-specific environment variable?
From: Doug Reeder (dlr_at_[hidden])
Date: 2008-10-20 18:45:00


Brian,

In your code branch for the parallel run you could set an environment
or internal variable when you call mpi_init. Can you parse the
command line (arg 0) and figure out if you are running parallel or
serial.

Doug Reeder
On Oct 20, 2008, at 3:40 PM, Adams, Brian M wrote:

> I work on an application (DAKOTA) that has opted for single
> binaries with source code to detect serial vs. MPI execution at run-
> time. While I realize there are many other ways to handle this
> (wrapper scripts, command-line switches, different binaries for
> serial vs. MPI, etc.), I'm looking for a reliable way to detect (in
> source) whether a binary has been launched in serial or with orterun.
>
> We typically do this via detecting environment variables, so the
> easiest path for me would be to know an environment variable
> present when an application is invoked with orterun that is not
> typically present outside that MPI runtime environment. Some
> candidates that came up in my particular environment include the
> following, but I don't know if any is a safe bet:
>
> OMPI_MCA_gpr_replica_uri
> OMPI_MCA_mpi_paffinity_processor
> OMPI_MCA_mpi_yield_when_idle
> OMPI_MCA_ns_nds
> OMPI_MCA_ns_nds_cellid
> OMPI_MCA_ns_nds_jobid
> OMPI_MCA_ns_nds_num_procs
> OMPI_MCA_ns_nds_vpid
> OMPI_MCA_ns_nds_vpid_start
> OMPI_MCA_ns_replica_uri
> OMPI_MCA_orte_app_num
> OMPI_MCA_orte_base_nodename
> OMPI_MCA_orte_precondition_transports
> OMPI_MCA_pls
> OMPI_MCA_ras
> OMPI_MCA_rds
> OMPI_MCA_rmaps
> OMPI_MCA_rmgr
> OMPI_MCA_universe
>
> I'd also welcome suggestions for other in-source tests that might
> reliably detect run via orterun. Thanks!
>
> Brian
> ----------
> Brian M. Adams, PhD (briadam_at_[hidden])
> Optimization and Uncertainty Estimation
> Sandia National Laboratories, Albuquerque, NM
> http://www.sandia.gov/~briadam
>
>
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