

ambEnergy.py compares Amber energies from GMIN binding and two different ways via OpenMM  

GMIN Input files are coords.inpcrd, coords.prmtop, min.in, data (required but not used). 
  The energy from Fortran GMIN is -21.7345926639 kcal/mol    

OpenMM calculations: 
  1. coords.inpcrd for coordinates and coords.prmtop for ff params 
  2. coords.pdb for coordinates and picks Amber ff params from OpenMM's built-in implementation
 
  Strangely the second calculation is in better agreement with GMIN energy! 


Output: 

ss2029@ubuntu:compare_with_ambgmin$ python ambEnergy.py 
Energies (kJ/mol)
AMBGMIN        OpenMM inpcrd/prmtop   OpenMM pdb/amb99sb  
-------------------------------------------------------- 
-90.9375356972 -90.9428083928 kJ/mol -90.9364375726 kJ/mol
ss2029@ubuntu:compare_with_ambgmin$ 

