[gmx-users] lattice Coulomb energy between energy groups

[Gavin Melaugh]

Hi Justin

Thanks for the reply. I take it then, if I use the maxwarn option, it
will still apply the exclusion for the short-range non-bonding interactions.

Cheers

Justin A. Lemkul wrote:
>
>
> Gavin Melaugh wrote:
>> Hi all
>>
>> I have set up a simulation with PBC using PME and specify an energy
>> group enclusion involving some virtual sites and a hydrocarbon chain.
>> i.e. hydrocarbon chain is one energy group and the virtual sites
>> constitute the other group. Grompp generates the following warning
>>
>> "Can not exclude the lattice Coulomb energy between energy groups"
>>
>> I have checked the mailing list and the manual but there doesn't seem to
>> be any concise answers. Given the fact that both groups are not charged
>> is it O.K. to ignore this warning.
>>
>
> Probably.  The warning indicates that one cannot use energygrp_excl to
> exclude components of the PME mesh; such exclusions only apply to
> short-range interactions that can be decomposed pairwise.  Since the
> PME mesh is dependent on all the entities in the system, there is not
> way to simply calculate the mesh, except for some interactions between
> groups A and B.  If there are no charges on groups A and B, you should
> be fine.
>
> -Justin
>