[gmx-users] energygrp_excl and PME

[David van der Spoel]

Abil Aliev wrote:
> Hello, 
>  
>  I have used mdp file for md runs with 
>  
>  coulombtype              = Cut-off 
>  
>  energygrps          =  Protein  SOL Terminal 
>  energygrp_excl     = Terminal Terminal Terminal SOL 
>  freezegrps          = Terminal 
>  freezedim           = Y Y Y 
>  
>  and had no warning messages on grompp-ing. But, when
> I change 
>  coulombtype              = PME 
>  
>  a warning message is issued by grompp: 
>  
>  "WARNING 1 [file "stide.top", line 40]: 
>  Can not exclude the lattice Coulomb energy between
> energy groups" 
>  
>  Is there anyway to avoid this warning by changing
> energygrp_excl or other options in the mdp file while
> keeping PME? 
>  
>

The file reference is not accurate, but the warning means that even if 
you exclude the interaction in real space there still is an interaction 
in fourier space, due to a restriction in the software.


-- 
David.
________________________________________________________________________
David van der Spoel, PhD, Assoc. Prof., Molecular Biophysics group,
Dept. of Cell and Molecular Biology, Uppsala University.
Husargatan 3, Box 596,  	75124 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://folding.bmc.uu.se
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