[gmx-users] Meaning of columns in .xvg output file

Justin Lemkul jalemkul at vt.edu
Mon Mar 6 14:19:07 CET 2017

On 3/6/17 5:36 AM, Kamps, M. wrote:
> Dear gmx-users,
> I've got a small question of which I can't find the answer. I have a
> simulation where I want to calculate the average velocity of certain
> particles. I've created an output .xvg file via the command:
> gmx traj -f input.trr -s input.tpr -n input.ndx -av output.xvg
> My output, is as requested an .xvg file which can be plotted in xmgrace.
> However, when opening this .xvg file with a text-editor, it has four
> columns of output, of which only the first two columns will be used by
> xmgrace. The first column is a simple counter, however the other three

You can plot everything with xmgrace -nxy output.xvg

> columns all contain values. Supposedly, the second column (column 2 of
> 4) contains the average velocities. My question: What are the values
> in column 3 and 4?

What do the labels in the header of the file say, or alternatively, what does 
the legend say when you plot with the above command?



Justin A. Lemkul, Ph.D.
Ruth L. Kirschstein NRSA Postdoctoral Fellow

Department of Pharmaceutical Sciences
School of Pharmacy
Health Sciences Facility II, Room 629
University of Maryland, Baltimore
20 Penn St.
Baltimore, MD 21201

jalemkul at outerbanks.umaryland.edu | (410) 706-7441


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