Tool to modify and add new information to GROMACS topology files. This is particularly useful when working with systems that were created outside of GROMACS (for example, files created in AMBER or CHARMM and then converted over via acpype). This tool can also be used to complement the "gmx insert-molecules" tool, which currently only modifies the GROMACS structure files (gro) and requires further modification of the topology file for the newly populated system to be simulation ready.

Input

1. The system topology file you are modifying,
2. a position restraint file (posres.itp) and specifying the name of the target molecule type you are restraining,
3. a molecule's atom types/nonbonded parameters to be inserted under the system's global [ atomtypes ], as well as
4. the corresponding bonded parameters of that particular molecule found under [ moleculetype ].

Outputs

The new modified GROMACS topology file.