An open-source, transparent, and lightweight Python software package capable of fitting dihedrals with QM calculations for existing forces fields. This software fits the Optimized Potentials for Liquid Simulations (OPLS) style dihedrals, then also analytically converts them to the periodic dihedral and Ryckaert-Bellemans (RB) torsion.
copied from cf-post-staging / mosdef-dihedral-fit