[gmx-users] Test Particle Insertion Problem-Gromacs 4.0.3

[Mark Abraham]

Harry Saavedra wrote:
> Dear All,
> 
> I run a test molecule insertion simulation using Gromacs 4.0.3. All the 
> molecules of the system work with two energy groups (two tabulated 
> potentials), and every atom belongs to a different charge group; but 
> Gromacs shows an error message:
> 
>  > grompp...
>  > mdrun ...
> 
> Program mdrun, VERSION 4.0.3
> Source code file: force.c, line: 1068 Send <javascript:;>
> Fatal error:
> The molecule to insert can not consist of multiple charge groups.
> Make it a single charge group.
> 
> 
> However,when I set all the atoms of the inserted molecule (A,B,C..) to 
> the same charge group (cgnr in the top file), Gromacs displays :
> 
> 
>  >grompp...
> 
> Program grompp, VERSION 4.0.3
> Source code file: grompp.c, line: 150
> Fatal error:
> atoms A and B in charge group Z of molecule type 'Protein' are in 
> different energy groups
> 
> 
> There is any way to overcome this problem? How Gromacs can ignore the 
> charge groups?

Energy groups are set in the .mdp file using the groups defined 
(implicitly) in the .ndx file. You need a charge group that is a subset 
of a single energy group.

Mark