[gmx-users] Error in grompp steps of position restrained

[Mark Abraham]

On 8/06/2012 12:23 PM, Malai wrote:
> Hi,
>
> After Successfully neutralizing and sd minimization of the system, I 
> got the below error when I try the grompp for position restrained 
> step. The command I used is :grompp -v -f eqn1.mdp -c complx_sd.pdb -p 
> complx.top -o complx_eqn1.tpr
>
> Any help will be highly appreciated.
>
> Many thanks.
>
>
> Error message:
>
> -------------------------------------------------------
> Program grompp, VERSION 4.5.5
> Source code file: readir.c, line: 1320
>
> Fatal error:
> Group CA not found in index file.
> Group names must match either [moleculetype] names
> or custom index group names,in which case you
> must supply an index file to the '-n' option of grompp.
> For more information and tips for troubleshooting, please check the 
> GROMACS
> website at http://www.gromacs.org/Documentation/Errors
> -------------------------------------------------------

Your .mdp file referred to a group for which grompp could find no 
definition. Choose a better group or make a definition.

Mark