Range checking error (gmx covar)

GROMACS version: 2020.5

I am trying to calculate the covariance for my system using gmx covar and C-alpha for the least squares fit. However, it gives me the following error:
“Range checking error (possible bug):
The provided structure file only contains 55028 coordinates, but coordinate index 3771 was requested for fitting. Make sure to update structure files and index files if you store only a part of the system”

While applying PBC, I save the whole system in the trajectory. Therefore, I do not understand why this error shows up.


I can not understand what can be the problem. Can you provide more information on the command line, you used?
Thank you

Hi Alessandra,

Thank you for the reply.
I use the command “gmx covar -s md.tpr -f md.xtc” for calculating the covariance matrix. The system consists of a protein in a cubic box with tip3p water model.
It works if I run the same command on supercomputer where the production MD was performed but not on my personal system.

Kindest Regards
Purvi Gupta

This is a bug in src/gromacs/gmxana/gmx_covar.cpp. Line 92 is:
if (largestIndex < largestOkayIndex)
But should be:
if (largestIndex >= largestOkayIndex)
If you installed Gromacs yourself, you can change this yourself, recompile and install.

Dear Hess,

Thank you so much. It works now. :)

Kindest Regards
Purvi Gupta