[gmx-users] More than one settle type

[Shalabh]

Hi,

I am trying to find the free energy of a water molecule as it adsorbs 
on a surface. My outline is:

1) Run the simulation
2) Analyze the results, find out which water molecule(s) are adsorbed
3) Create different groups for the water adsordbed molecule(s), create 
new .gro file (to identify the adsorbed water with different residue 
name), .mdp file and .tpe file. The remaining water molecules have the 
same previous group name.
4) Use mdrun -rerun to evaluate the energy between the new water 
group(s), the surface and the remaining water.

When I try to implement this, I get an error in step 4 while running 
mdrun -rerun, saying "More than one settle type. Suggestion: change the 
least use settle constraints into 3 normal constraints". The .itp file 
which I created for the new water group is identical to the spc.itp 
file (with the only change as the residue name).

This similar problem was raised earlier as well, which I am not sure 
if it was resolved:
http://lists.gromacs.org/pipermail/gmx-users/2010-January/048058.html

Basically, what I am trying to do is if I have 1000 water molecules in 
my system, can I have 999 of them in one group SOL, and the remaning 1 
water molecule in a different group, say SOL1. The .itp files and 
parameters are identical, apart from the group (residue) name. And I am 
getting the above error. Anyone any ideas?

Thanks in advance!