[gmx-users] multiple T-Coupling

[Mark Abraham]

best alep wrote:
> Good Day to all GROMACS users,
> 
> Firstly thanks to Martin for replying my mail. I have another problem, 
> actually I'm a new student and a new user of this software.
> When i use grompp, there's error message like this:
> "Fatal error:
> Atom 1 in multiple T-Coupling groups (1 and 2)"
> What's the meaning of this error? is it related to my residue database? 
> because i modified the residue database (*.rtp) to include mine. Can 
> anyone help me? What should i do and where should i look?

Curiously, this means that the first atom in your topology is in two 
temperature-coupling groups. The T-coupling groups are defined in your 
.mdp file. Obviously you can't want to constrain the same atom to two 
different temperatures, so grompp doesn't let you have an atom in two 
temperature-coupling groups. Probably you need to read the manual 
section on tcgroups in 7.3 and adjust your .mdp file.

Mark