# 'gmx wham' counts wrong column number in the pull coordinate selection file **URL:** \ **Category:** User discussions\ **Tags:** analysis-tools\ **Created:** [March 10, 2024, 10:05am UTC](https://gromacs.bioexcel.eu/t/gmx-wham-counts-wrong-column-number-in-the-pull-coordinate-selection-file/8565 "2024-03-10T10:05:41Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![lcc1992](https://avatars.discourse-cdn.com/v4/letter/l/da6949/32.png) [@lcc1992](https://gromacs.bioexcel.eu/u/lcc1992)\ **Post date:** [March 10, 2024, 10:05am UTC](https://gromacs.bioexcel.eu/t/gmx-wham-counts-wrong-column-number-in-the-pull-coordinate-selection-file/8565/1 "2024-03-10T10:05:41Z")
GROMACS version:2023.4 GROMACS modification: No Dear GROMACS Users, I performed Umbrella Sampling of one nanoparticle interacting with one slab with 2 reaction coordinates: one is to pull the nanoparticle along z-direction, and the other is to restrain the nanoparticle from moving in the XY-plane. ; Pull code pull = yes pull\_ncoords = 2 pull\_ngroups = 2 pull\_group1\_name = NP\_Center pull\_group2\_name = Slab\_Center pull\_coord1\_type = umbrella pull\_coord1\_geometry = distance pull\_coord1\_dim = N N Y pull\_coord1\_groups = 1 2 pull-coord1-init = 10.00 pull\_coord1\_start = no pull\_coord1\_rate = 0 pull\_coord1\_k = 500 pull\_coord2\_type = umbrella pull\_coord2\_geometry = distance pull\_coord2\_dim = Y Y N pull\_coord2\_groups = 1 2 pull-coord2-init = 0 pull\_coord2\_rate = 0 pull\_coord2\_k = 50000 After the simulations, I used ‘gmx wham -is coordsel.dat -it tpr-files.dat -ix pullx-files.dat -o -hist -unit kJ -min 10.00 -max 13.00’ to analyze the first pull coordinate with the ‘coordsel.dat’ as follows: 1 0 1 0 … 1 0 I got the error: Found 2 pull coordinates in XXX.tpr, but 3 columns in the respective line coordinate selection file (option -is). But it has 2 columns in the ‘coordsel.dat’. Does anyone have experience with that? Thank you vey much. Best regards, Chuncheng ---
**Author:** ![MagnusL](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/magnusl/32/2380_2.png) [@MagnusL](https://gromacs.bioexcel.eu/u/MagnusL)\ **Post date:** [March 11, 2024, 9:14am UTC](https://gromacs.bioexcel.eu/t/gmx-wham-counts-wrong-column-number-in-the-pull-coordinate-selection-file/8565/2 "2024-03-11T09:14:16Z")
So, either there is a problem with your `coordsel.dat` file, or there is some kind of issue when reading it. Could you post the file here? Anyway, as a future recommendation, it might be easier to run this kind of simulations with one pull coordinate and using restraints along X and Y. ---
**Author:** ![lcc1992](https://avatars.discourse-cdn.com/v4/letter/l/da6949/32.png) [@lcc1992](https://gromacs.bioexcel.eu/u/lcc1992)\ **Post date:** [March 12, 2024, 3:04am UTC](https://gromacs.bioexcel.eu/t/gmx-wham-counts-wrong-column-number-in-the-pull-coordinate-selection-file/8565/3 "2024-03-12T03:04:11Z")
Thank you for your recommendation. I have run the simulation with one pull coordinate and using restraints along X and Y. It works well. And I’ve uploaded the coordsel.dat file when I ran the WHAM analysis. Thank you very much. [coordsel.dat](https://gromacs.bioexcel.eu/uploads/short-url/utQ8Ie5CIsbeYX1zIaAhaBiguVn.dat) (80 Bytes) ---
**Author:** ![MagnusL](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/magnusl/32/2380_2.png) [@MagnusL](https://gromacs.bioexcel.eu/u/MagnusL)\ **Post date:** [March 13, 2024, 10:01am UTC](https://gromacs.bioexcel.eu/t/gmx-wham-counts-wrong-column-number-in-the-pull-coordinate-selection-file/8565/4 "2024-03-13T10:01:59Z")
Good that it helped. I had a look at your file and it looks correct, assuming that there are 16 tpr input files. We should have a look at this issue.