[gmx-users] Re: Tabulated potentials and normal nonbonded interaction at the same time

[Thomas Schlesier]

>> Hi,
>> first, thank you for you're answers.
>> I looked more into the stuff.
>>
>> I think i would use the following setup:
>>
>> Since the CG-solvent is uncharged, i can use the normal coulomb-
>> interaction (PME) for the system.
>>
>> For the vdw-part, i would use 'vdw_type=user' and:
>> energy_grps = CG Mol
>> energygrp_tables = CG CG (CG self-interaction) CG Mol (CG-
>> Molecule interaction)
>> (CG = CG-solvent; Mol=Molecule)
>> So i would need two tables (for each interaction one).
>> With this i should get all the vdw-interaction where the CG-
>> solvent is involved.
>>
>> But since i need normal vdw-interactions for the Molecule self-
>> interaction, i would need in the .mdp-file
>> 'vdw_type = user' AND 'vdw_type = cut-off'
>>
>> Or am i wrong (hope so)? Because the only way i can think of to 
>> solve the problem, would be that i make for every vdw-self-
>> interaction of the Molecule an own table, which wouldn't be good 
>> (since i read somewhere that tables are slower then to 
>> calculated the interaction normally).
>>
>> So how could i solve the problem, or this there no problem 
>> because i didn't understand the whole stuff correctly (seems so 
>> because of Marks reply)?
> 
> I haven't ever actually done it, but I'm expecting "vdw_type= cut-off" and "energygrp_tables = CG CG CG Mol" to work if you supply the two tables. What I can see in the manual neither confirms nor denies this, but it is cost-free to try :-)
> 
> Mark

Ok, i will try it and report back if it works.
Thomas