Analysis of FEP output file

From: sudipta (sudipta.mml_at_gmail.com)
Date: Tue Jan 31 2012 - 11:41:33 CST

Hi everyone,

I want to perform FEP calculations using NAMD. Therefore, I have finished
my calculation according to tutorial and want to estimate the error of free
energy (BAR estimator) by using the parsefep plugin of VMD (v 1.9).
However, during this analysis, I am getting an error constantly that I
cannot resolve it. I put the error message below.

*Error: domain error: argument not in valid range.*

I have divided the whole path as

runFEP 0.0 0.01 0.001 $numSteps
runFEP 0.01 0.1 0.01 $numSteps
runFEP 0.1 0.9 0.1 $numSteps
runFEP 0.9 0.99 0.01 $numSteps
runFEP 0.99 1.0 0.001 $numSteps

for forward direction and

runFEP 1.0 0.99 -0.001 $numSteps
runFEP 0.99 0.9 -0.01 $numSteps
runFEP 0.9 0.1 -0.1 $numSteps
runFEP 0.1 0.01 -0.01 $numSteps
runFEP 0.01 0.0 -0.001 $numSteps

for backward direction
I have chosen the numSteps as 1500 and alchequilsteps as 500

Insted of this above division, if I choose those as

runFEP 0.0 0.1 0.001 $numSteps
runFEP 0.1 0.9 0.01 $numSteps
runFEP 0.9 1.0 0.001 $numSteps

runFEP 1.0 0.9 -0.001 $numSteps
runFEP 0.9 0.1 -0.01 $numSteps
runFEP 0.1 0.0 -0.001 $numSteps

for forward and backward direction then the calculations are finished
without any error. So, what is my wrong?

Can anyone highlight in this regard.

Thanks
Sudipta 

-- 
==========================================================
   Dr. Sudipta Kumar Sinha                         ||
   Postdoctoral Employee                           ||
   C/O Prof. Leonor Saiz                             ||
   Department Of Biomedical Engineering     ||
   University of California, Davis                   ||
   U.S.A                                                    ||
   Email-sudipta.mml_at_gmail.com <Email-sudipta_at_chem.iitkgp.ernet.in>
||
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