C++ OpenMP on multiple nodes [duplicate]

Question

I have a question...

I know OpenMP on a single computer over the multiple cores in that machine, but is OpenMP capable of running over several nodes like 2 machines? Or do I absolutely have to use MPI? I know OpenMP has shared memory architecture, where MPI is distributed memory architecture, so is my assumption correct that OpenMP will only work on a single machine?

Answer 1

you must recode your app to a 2 level parallelism:

mpi - you reduce your task to a nodes. mpi works with a process.

openmp - parallel into node. openmp works with threads.