[gmx-users] workaround for PME coulomb energy (fwd)

[K.A. Feenstra]

David L. Bostick wrote:
[...]
> An additional question..  as a check.. I am trying to do -rerun while
> energy monitoring Na and !Na groups with a large cut-off instead of PME.
> This way I can directly get a good estimate of the coulomb energy.
> However, I would imagine that Coul-SR:Na-notNa is all I need since I am
> using cutoff, but I see that there is a nonzero Coul-LR:Na-notNa.  Why is
> this?

The rest of your issues are way over the top for me, but this one I can take... ;-)

You're probably using a twin-range cut-off, like 0.8/1.0, or 0.8/1.5 or so.
Thus, you have a short and long range part... In PME the long range (i.e.
what was between 0.8 and 1.5 in the twin-range cutoff) part is replaced by
the PME part (which now takes 0.8 to infinity).


-- 
Groetjes,

Anton
  ________ ___________________________________________________________
|        | Anton Feenstra                                            |
| .      | Dept. of Pharmacochemistry - Vrije Universiteit Amsterdam |
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