Templates for Slurm job submission scripts are available for batch GROMACS jobs in /opt/shared/templates/slurm/applications/gromacs. Copy and edit the template based on your job by following the usage described in gromacs.qs.
/opt/shared/templates/slurm/applications for changes in existing templates, or the addition of new templates, designed to provide the best performance for a particular version of GROMACS on that cluster.
On Caviness, the template (/opt/shared/templates/slurm/applications/gromacs.qs) provides a number of options to provide the best performance, but you must read the comments and set the options accordingly for your job. By default the template uses double-precision (md_rund), however commenting out GROMACS_DOUBLE_PRECISION=YES will specify the single-precision version (md_run) instead.