Gmx_mpi doesn't run

GROMACS version: 2020.3
GROMACS modification: No
I have installed GROMACS and then built mdrun only to have mpi support. I am following the instructions here without modification. However, after I’ve compiled and installed everything, and checked that all my tests have passed, I still cannot get gmx_mpi to run. The following error shows up:

Why does it say “error on file gmx_mpi (no such file or directory)”?

Any help would be greatly appreciated

You have to tell the computer where to look for the “gmx_mpi” binary before you can use it.

It seems you are skipping the “source” step at the bottom of the “quick and dirty installation” section from the link you posted.

Try: “source /path/to/gromacs/install/bin/GMXRC” without quotes and replace the path with where you installed the gromacs binaries. The default location is /usr/local/gromacs/

Forgot to mention - since you installed an mdrun-only version of GROMACS, the binary you will use to launch mdrun will not be “gmx_mpi mdrun” but instead “mdrun_mpi” (if you didn’t mess with the default suffixes).

See the “Quick and dirty cluster installation” section in the link you posted.

I did source GMXRC and gmx runs, just not gmx_mpi. I didn’t alter the default suffixes. I haven’t tried “mdrun_mpi” yet, so I’ll try that and let you know how it goes!

mdrun_mpi ran! Thank you! Still a lot that I need to figure out about running on multiple nodes but at least I’m running