GROMACS version: 2023
GROMACS modification: No
This is somewhat a trivial matter but would it be complicated to make OPC an optional enum option inside of gmx pdb2gmx? I’m often relying on workflows to automate system preparation, and the only thing that I have to do manually is to interactively select the water model, because --water opc is not a legal choice (even though the .ff has opc.itp inside, and OPC is “recommended” in my watermodels.dat).
I know there are at least two workarounds, put OPC parameters into tip4p.itp or use echo "1 1" | gmx pdb2gmx ..., but both will one day lead to confusion if the context changes, so no foolproof/future-me-proof.
Alternatively, options available for the command-line --water could be read from watermodels.dat, as is already done during interactive selection.
OPC is getting popular in quite a few subfields, and so are automated workflows, so I guess this will only become more problematic with time.