From: surya narayanan chandrasekaran (
Date: Wed Jan 16 2019 - 07:00:25 CST


    I was doing alchemical FEP tutorial. After doing the forward and
backward step i was trying to analyse the .fepout in the vmd plugin and got
the below error. My computer is Linux based (ubuntu 18) and i have xmgrace
and gnuplot installed in it.

option i selected in the plugin:
GRM-Charlier: 0
disp (on) for unix ststems only
forward and backward .fepout file loaded

Error: missing close-bracket

missing close-bracket
    while executing
"set lambda1 [format "%8.4f" [lindex $::ParseFEP::fwd_lambda $index]
                                        set lambda2 [format "%8.4f"
[lindex ..."
    invoked from within
"if { [file exists [format "file%d.dat" $file_index] ] } {
                                        set lambda1 [format "%8.4f"
[lindex $::ParseFEP:..."
    (procedure "::ParseFEP::fepdisp_unix" line 321)
    invoked from within
"::ParseFEP::fepdisp_unix "
    (procedure "namdparse" line 47)
    invoked from within
    (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 ..."
    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)

Warm regards,
Dr. Suryanarayanan C