On the OMNI cluster, GROMACS is installed in version 2021.1 (whose user guide can be found here) and 2018.6. If you only type
module load gromacs, version 2021.1 is loaded by default. If you want to select the version yourself, you can display the module names with the following command:
$ module avail gromacs gromacs/2018.6 gromacs/2021.1
You can then load a version explicitly with e.g.
module load gromacs/2018.6.
The command to start GROMACS is
gmx_mpi. Note that the GROMACS documentation only mentions the
gmx command, the two are otherwise identical. You can display an overview of available options with
gmx_mpi help. Here is a more detailed list.
Caution: if you run GRAOMACS in an interactive job, you have to specify the MPI version when queuing the job, for example like this:
srun --pty --mpi=pmix_v3 gmx_mpi --version
Usage with GPUs
The version 2021.1 also supports usage of GPUs. Please refere to GPU usage for further information.