'''
IRFF: Intelligent Reactive Force Filed, A ReaxFF developing tool kit.
Authored by FengGo.
email: fengguo@lcu.edu.cn
       gfeng.alan@foxmail.com

This software package is under academic license.

  2019-05-06:
     version 3.3 fix bugs of NLP, PBO calculation 
                          Delta_angle index error
  2019-04-16
     version 3.2 weight added
  2019-04-02:
     version 3.1 change log, test of torsion energies,
     found eover and eunder bugs(fixed)
     add penalty for case of bond-order to small

'''

