From: Amy Rice (
Date: Mon Feb 18 2019 - 15:16:00 CST

Hi all,
I noticed that using different versions of ParseFEP (1.9.2 vs 2.1) gives
different free energy output when supplied with the same fepout files and
temperature selection. With 1.9.2, the free energy change was calculated as
-89.320 with a total error of 0.099. The same files in version 2.1 resulted
in a free energy change of -98.704 and a total error of 0.071. Is this
expected behavior? In both cases, I set the temperature to 310 K and
selected to use the BAR-estimator method. Was there a change in how the
calculation is performed between these two versions? It is a little
disconcerting to have such a large difference between the two. I have
attached the log file for both cases.


Amy Rice
Ph.D. Candidate
Physics Department
Illinois Institute of Technology