This is not an Open MPI question, and hence not a fit for this mailing list.
But here we go: first, try cmake -DGMX_MPI=ON ... if it fails, try cmake -DGMX_MPI=ON -DCMAKE_C_COMPILER=mpicc -DCMAKE_CXX_COMPILER=mpicxx . .. Cheers, Gilles ----- Original Message ----- Hi, MPI developers and users, I want to run GROMACS using gmx_mpi rather than gmx, could you give me a hand on how to do that? Thanks a lot! Cheers,