Please note: The FAQ pages at the HPCVL website are continuously being revised. Some pages might pertain to an older configuration of the system. Please let us know if you encounter problems or inaccuracies, and we will correct the entries.
To run MPI programs, a special Runtime Environment is required. This differs from platform to platform. On our Sun machines, which run Solaris, it is called ClusterToolsor CT. This includes commands for the control of multi-process jobs. The most important ones are:
mprun -np 9 test_mpi.exe [ClusterTools 6]
mpirun -n 9 test_mpi.exe [ClusterTools 8.1]
The mprun and mpirun commands offer additional options that are sometimes useful or required. Most tend to interfere with the scheduling of jobs in a multi-user environment such as ours and should be used with caution. Please consult the man pages for details.
Finally, the -x sge option (only CT6) is used to indicate that the node list for the processes is supplied by the Gridengine scheduling software. This option is used when MPI programs are executed via Gridengine, and appears normally inside of Gridengine submission scripts. If -x sge is specified, the number of processes does not have to be specified anymore, since it will be determined by the Gridengine. A command line looks like this:
mprun -x sge program.exe
Note that the usage of Gridengine is mandatory for production jobs on our system. This option is therefore used frequently. For a details about Gridengine and jobs submission on HPCVL machines and clusters, go here.
Note that the usage of the -x sge option is not supported if you use ClusterTools 8, as the mpirun command detects usage through Grid Engine automatically. In this case, the -n option is not used either, bringing the command line down to a simple