Error in setting up xplor calculation

I am using version 3.1.0 beta and trying to set up a Xplor structure calculation. But during the run I am getting the following error. assignmentInfo=createShiftAssignments(shifts,noePot,
Traceback (most recent call last):
  File "<string>", line 2, in <module>
  File "/home/debadutta/xplor/xplor-nih-3.5/python/", line 180, in run
    exec(cmd, dict, dict)
  File "<string>", line 1, in <module>
  File "/home/debadutta/xplor/xplor-nih-3.5/python/", line 137, in execfile
    exec(code, globals, locals)
  File "", line 84, in <module>
  File "/home/debadutta/xplor/xplor-nih-3.5/python/", line 218, in func_wrapper
  File "/home/debadutta/xplor/xplor-nih-3.5/python/pasd/", line 1429, in createShiftAssignments
    shiftSelectionList.append( (float(val),float(err),sel) )
ValueError: could not convert string to float: '.'

Can anyone help me figure out what’s happening and how to troubleshoot.


Hi Debadutta,

Is it possible that some of your NOESY peaks do not have volumes? Peak volume is not estimated by default during peak picking in version 3.1.

If that is the case, go to Main Menu > Spectrum > Estimate Peak Volumes… (keyboard shortcut E, V).

Let us know if that helps.

Best wishes,

Hello Eliza,
I checked the NEF file and peak volumes were present for all NOESY picks. I was able to circumvent this error by deleting some decimals in the position of the chemical shift to roughly align all the columns in C-NOESY and N-NOESY. It seems like xplor has some issue with parsing the NEF file.
Please let me know if I am doing something wrong here.

Thanks for replying


Hi Debadutta,

I have to say I have never noticed that in Xplor NIH.

It would be very helpful if you could send me ( your NEF file (and ideally your project, no need for spectra). Would that be possible?

Best wishes,