[gmx-users] replica exchange doubt

[Berk Hess]

>From: "Andrea Carotti" <and.carotti at farmchim.uniba.it>
>Reply-To: Discussion list for GROMACS users <gmx-users at gromacs.org>
>To: <gmx-users at gromacs.org>
>Subject: [gmx-users] replica exchange doubt
>Date: Tue, 11 Apr 2006 13:14:51 +0200
>
>Hi all gmx-ers,
>I have a doubt concerning the REMD setup. Let's say I want to use 12 cpus 
>to make a REMD at 2 different temp 300 and 400K of the same system.
>Should I prepare every tpr file with the -np option set to 6?
>and then run the mdrun with -np 12 -multi -s 300.tpr 400.tpr -replica X 
>-reseed?

That is not possible with Gromacs 3.3.
You can only do single processor simulations.
It will be available in Gromacs 4.0.

BTW I hope your values are just for the sake of the example,
using only 2 temperatures or a 100K difference will not give
good sampling.

>The last doubt: is it possible/supported to make a REMD with an Umbrella 
>sampling (a force between 2 centers of mass)associated?

All normal mdrun functionality should work, except for things that
use a history, such as time averaged restraining.

Berk.