Divide by Zero problem with titration analysis

[foster.281]

Hi Bruce and NMRViewJ afficionados,

I'm stuck on implementing the titration analysis tool in NMRViewJ 9.2-b20, getting a divide by zero error when I try to "Measure" the peak shifts:

divide by zero
    while executing
"expr {$di/$refInt}"
    invoked from within
"set di [expr {$di/$refInt}]"
    ("if" then script line 7)
    invoked from within
"if {$pars(valtype) eq "Shift"} {
            set x2 [nv_peak elem 1.P $peak]
            set y2 [nv_peak elem 2.P $peak]
            set dx [expr {($x..."
    ("foreach" body line 5)
    invoked from within
"foreach peakConc $peakData {
        set peak [lindex $peakConc 0]
        lappend pars(pathPeaks) $peak
        set list [::nv::peak::getListFromPeak..."
    ("if" else script line 9)
    invoked from within
"if {$pars(measureMode) eq "Single"} {
        set peak [lindex [nv_win selectpeak] 0]
        foreach peakConc $peakData {
            set list [linde..."
    (procedure "::nv::titration::measurePeak" line 96)
    invoked from within
"::nv::titration::measurePeak"
    ("binding" script)

I followed the instructions here: http://docs.nmrfx.org/viewer/ratesandbinding/titration as closely as I could (there is no "Find Path" button, for example):

Read in 7 nv datasets (test001.nv thru t007.nv)

Overlaid the spectra in one window, set contour level, and peak-picked. This generated 7 xpk files named as the datasets.

I then created a concentration file, with each line indicating the root for the file name (e.g., 001 0) for the test___.nv file, and concenration of ligand.

Launched titration analysis tool, entering the prefix "test", suffix ".nv", protein concentration, the click on "Read Conc. File" -- this seemed to properly load the spectra into the window, and I can display the first, last or all peaks.

Clicking "Measure" on peaks with significant perturbations appears to be successful in mapping the "path", as a green line is drawn from the first to the last peak. However, it also bring up the tcl error, and the values are not shown in the graph, or updated to the "data" tab.

Any suggestions would be greatly appreciated!

-Mark Foster

OSU