=== Dependencies === These programs depend on mpi4py (>= Version 1.0) The mpi4py documentation and installation instructions can be found at: http://mpi4py.scipy.org/ === How to run on a single (multi-core) host === Run it with mpirun -np 4 ./some-program where the number after "-np " is the numer of parallel MPI processes to be started. === How to run on multiple hosts === If you want to run the program distributed over multiple hosts, you have to create a <hostfile> which looks like: -- hostfile -- host1 slots=4 host2 slots=4 host3 slots=4 -------------- Where "slots=" specifies the number of parallel processes that should be started on that host. Run it with mpirun --hostfile <hostfile> ./some-program === Run on a cluster with the Torque Job schduling system === There are two possibilities: a) Run interactively: Request an interactive session and allocate a number of processors/nodes for your session: $ qsub -I X -l nodes=4:ppn=4 Where "-I" means you want to work interactively, "-X" requests grapical (X-Window) I/O -- (you can run arbitrary programs that open windows). The option "-l " specifies the resources you want to allocate. "-l nodes=4:ppn=4" requests four compute nodes with each having four processor cores [ppn =^ ProcessorsPerNode]. So in total you allocate 16 CPU cores. [The scheduler is free to run your job on two nodes having 8 CPU cores each] Once your interactive session is ready, you run $ mpirun ./your-program mpirun automatically knowns how many parallel processes have to be started and where they have to be started. b) Submit as non-interactive batch-job: Use $ qsub -l nodes=4:ppn=4 ./your-jobfile.job to submit jour job-file. Similar to the interactive case, "-l" again is used to request resources from the scheduling system. The job file usually is a simple shell script which specifies the commands to be run once your job starts. In addition, the jobfile can contain "#PBS <something>" statements which are used to specify additional options which could have been specified in the "qsub" commandline. Please see "man qsub" for details.