AMBER Archive (2003)

Subject: AMBER: Ewald in Amber 7

From: Ben Cossins (bcc_at_soton.ac.uk)
Date: Fri Dec 19 2003 - 09:49:11 CST


Dear All,
     Is it possible to have a non-ewald simulation in AMBER 7? I have been
told that Ewald is always on in AMBER 7. Yet I have also seen a mail (below)
in the AMBER archive which says if ntb=0 and igb=0 you get a non-ewald
simulation. Which is the case?

It seems to me that Ewald is always on, as when I run an ibelly simulation in
AMBER 7 with ntb=0 and igb=o I get a warning about using Ewald with ibelly.

Thanks

Ben

On Tue, Jul 09, 2002, Sarangan Ravichandran wrote:

>
> I have been using sander_classic (AMBER6)
> to do simulated-annealing simulations
> on a non-periodic system in vacuum with
> distance-dependent dielectric(IDIEL=0).
> I am trying to move my calculations to AMBER7.
> If I understand correctly in sander,AMBER7, I should
> use eedmeth (=5) to achieve the same thing.
> But, the eedmeth variable should only be set inside
> the &EWALD namelist. if I do not want to
> use Ewald for my long-range calculations, then
> what option(s) should I choose for my simulations?
>

If you set ntb=0 and igb=0 you will get a non-ewald simulation. If you
then set eedmeth=5 in the &ewald namelist, you get an r-dielectric, but
it is still not Ewald.

I know it is counterintuitive to put eedmeth into the &ewald namelist
section -- that's historical. In the future, we'll add a variable with
a better name to the &cntrl namelist to do the same thing, but for now,
you need to set eedmeth in the way you specify.

..hope this helps....dac

-- 

================================================================== David A. Case | e-mail: case_at_scripps.edu Dept. of Molecular Biology, TPC15 | fax: +1-858-784-8896 The Scripps Research Institute | phone: +1-858-784-9768 10550 N. Torrey Pines Rd. | home page: La Jolla CA 92037 USA | http://www.scripps.edu/case ==================================================================

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