About parseFEP error

From: Atsutoshi Okabe (atsutoshi0708_at_gmail.com)
Date: Wed Feb 03 2016 - 08:01:21 CST

Dear all,

I would like to calculate the standard binding free energy of a ptotein-ligand complex as written in Chipot’s tutorial "Protein:ligand Standard Binding Free Energies: A Tutorial for Alchemical and Geometrical Transformations”.
I had the following error when parseFEP with vmd was performed for BAR estimator.

domain error: argument not in valid range
domain error: argument not in valid range
    while executing
"expr { ( $elem1 * 1.0 ) / ( $sum1 * 1.0 ) }"
    (procedure "::ParseFEP::inaccuracy_estimation" line 112)
    invoked from within
"::ParseFEP::inaccuracy_estimation"
    (procedure "namdparse" line 160)
    invoked from within
"namdparse"
    (in namespace inscope "::ParseFEP" script line 16)
    invoked from within
"::namespace inscope ::ParseFEP {

                if { [string length $::ParseFEP::fepofile] < 1 } {
                        tk_dialog .errmsg {NamdPlot Error} "No FEP (inward) logfile ..."
    invoked from within
".parseFEP.runbutton invoke"
    ("uplevel" body line 1)
    invoked from within
"uplevel #0 [list $w invoke]"
    (procedure "tk::ButtonUp" line 22)
    invoked from within
"tk::ButtonUp .parseFEP.runbutton"
    (command bound to event)

Actually, the parseFEP calculation was stopped just after the free energy between lambda1=0.08 lambda2=0.10 was output as below.
Could you tell me why the parseFEP was stopped in the middle of the calculation?

backward: 7500 4 645345921.88316 526922738.73326 5.14508
backward: 15000 2 208501667.16186 294865885.47770 1.66230
backward: -----------------------------------------------------------------------------------------------------
backward: ParseFEP: Summary of thermodynamic quantities in kcal/mol
backward: -------------------------------------------
backward: ??A (FEP) = -17.269223714341333 ?A (FEP) = -58.079046435087236
backward: -------------------------------------------
backward: errorFEP: Error estimate from 1-st order perturbation theory:
backward: kT = 0.596160
backward: 1+2? = 2.993228
backward: N/(1+2?) = 10022.624560
backward: <exp(-2?U/kT)> = 18331548881392258078535057408.000000
backward: <exp(-?U/kT)> = 3805357593922.816406
backward: <exp(-?U/2kT) > = 206075.361132
backward: ?**2 = <exp(-2?U/kT)> - <exp(-?U/kT)>**2 = 18317068134974632252051292160.000000
backward: ?**2 = <exp(-?U/kT)> - <exp(-?U/2kT)>**2 = 3762890539457.045410
backward: ————————————å—————————————————
backward: ??**2 = 449.5631
backward: ?**2 = 1735.5370
backward: ??? = 0.2118
backward: ?? = 0.3687
backward: -----------------------------------------------------------
Inaccuracy estimation
======================================================================================================
             i i+?i P0_overlap_P1 ??(forward)/? ??(backward)/?
======================================================================================================
inaccuracy: 0.00000 0.02000 37.27 -0.46 0.48
inaccuracy: 0.02000 0.04000 21.14 -0.89 0.91
inaccuracy: 0.04000 0.06000 15.15 -1.09 1.11
inaccuracy: 0.06000 0.08000 14.14 -1.11 1.13
inaccuracy: 0.08000 0.10000 12.81 -1.13 1.15

Best regards,
Atsutoshi

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