[gmx-users] g_chi

Justin A. Lemkul jalemkul at vt.edu
Mon Apr 4 22:43:29 CEST 2011

simon sham wrote:
> Hi,
> I have 2 questions on using g_chi to calculate only one omega angle for 
> X-Pro.
> 1. I used the following command:
> "g_chi -s md.gro/tpr -f md.xtc -omega -o test.xvg" and got the following 
> message:
> Fatal error:
> Library file in current dir nor  not found aminoacids.datin default 
> directories.
> (You can set the directories to search with the GMXLIB path variable)
> For more information and tips for troubleshooting, please check the GROMACS
> website at http://www.gromacs.org/Documentation/Errors"

Upgrade to a newer version of Gromacs.  This bug has been fixed.

> 2. The command does not allow using index file. How can I calculate just 
> one dihedral angle?

Not sure on this one, but once you have a properly-functioning executable, you 
should be able to tell from the output files (of which there is a .log file that 
should contain everything).


> Thanks for your help in advance.
> Simon Sham


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


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