Running MPI jobs

To run MPI job, you should load OpenMPI module as an e.g.:

module load OpenMPI

You can press tab button twice to see the available versions. See ...

This loads the default OpenMPI module and define the environment variable OMPI_MCA_btl=self,vader,tcp. . There are also other versions if you need any other. To search for them run module spider OpenMPI.

There are several ways of launching an MPI application within a SLURM allocation, e.g. srun, mpirun, mpiexec. Unfortunately, the best way to launch your program depends on the MPI implementation (and possibly your application), and choosing the wrong command can severely affect the efficiency of your parallel run. What we recommend is the following:

mpirun -np $SLURM_NTASKS your_code &> log.out