[gmx-users] Re: g_wham

Justin Lemkul jalemkul at vt.edu
Mon Oct 1 02:32:25 CEST 2012

Please keep all Gromacs-related correspondence on the gmx-users mailing list.  I 
am CC'ing this message there and would ask that all further correspondence be 
posted to the list so that you can benefit from commentary from the entire 

See comments below.

On 9/30/12 2:09 PM, Chris Shuck wrote:
> Hello,
> I'm hoping you can help me with this. I was running umbrella sampling and was
> having an issue. In running g_wham I get this error:
>   Program g_wham, VERSION 4.5.5
> Source code file: futil.c, line: 459
> File input/output error:
> histo.xvg
> For more information and tips for troubleshooting, please check the GROMACS
> website at http://www.gromacs.org/Documentation/Errors
> I used the following command:
> g_wham -it umb.dat -if pullf.dat -o -hist -unit kCal
> umb.dat contains:
> umbrella0.tpr
> umbrella1.tpr
> ... etc
> pullf.dat contains:
> pullf-umbrella0.xvg
> pullf-umbrella1.xvg
> ...etc
> Now, the issue I may be experiencing could be due to what I have in the folder.
> I do not have the TRR files in this folder, only GRO, XTC, and XVG files. Is
> that an issue? I was under the impression that g_wham does not require TRR or
> LOG files. Can you shed any light on this issue?

I/O errors suggest you do not have sufficient read/write permissions on the 
working directory or perhaps enough disk space.

You do not need anything beyond .tpr and and .xvg files in the working 
directory.  From your description, it seems you do not have the .tpr files 
there, so that could be one potential problem, but I would expect a different 
error message in that case.



Justin A. Lemkul, Ph.D.
Research Scientist
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080


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