The simplest way of getting started with MPI is to install an MPI implementation (we recommend Open MPI) and mpi4py and then start the engines using the mpirun command:
mpirun -n 4 ipengine --mpi=mpi4py
This will automatically import mpi4py and make sure that MPI_Init is called at the right time. We also have built in support for PyTrilinos, which can be used (assuming PyTrilinos is installed) by starting the engines with:
mpirun -n 4 ipengine --mpi=pytrilinos