Here are files for generating and validating the Charmm22* force field.  

1.  We generate the force field files from Vipar3 files.  

2.  We validate the energies as well as the individual parameters in each force in the system.  Validation is performed on vacuum calculations of Trp-cage (2JOF) and hp35.  

The files are as follows:

CompareEnergies.py: validate OpenMM energies against Desmond and Gromacs.

CompareForceParameters: validate OpenMM force parameters against Desmond DMS file.

Comparison.py: A library for comparing DMS and OpenMM force parameters.

DesmondCommands.sh: commands necessary for preparing DMS files.

DMSReader.py: Reads force parameters from DMS file.

forcefield.py: Modifications to forcefield.py necessary for Charmm22*.

force_groups.py: Set force groups to divide energy terms.

OpenMM_Data.py: Construct an object containing the individual force terms in OpenMM system.

Viparr3Parser.py: Create XML file for Charm22* force field.