Assigning N cores per MPI rank

Question

I'm trying to assign N cores per MPI rank. I'm running an application with 256 MPI ranks, and I would like to assign 16 cores per MPI rank.

The solutions I found are useful but want me to use a rankfile and this gets tedious after a certain number of rank-core relationship.

Is there a better way to do it?

Answer 1

With Open MPI, you can

mpirun --map-by node:PE=16 ...