Re: AMBER: How do you evaluate forces on a fixed atom?

From: David A. Case <>
Date: Tue, 2 Dec 2008 09:39:37 -0500

On Mon, Dec 01, 2008, Bill K wrote:

> Has anyone tried to extract the systematic forces on a fixed
> atom, or may know how to do it? I'm using amber7 and, if you have an
> atom fixed in the system, the forces on it are canceled before they
> can be evaluated. That is to say, output prints values of 0.0 0.0 0.0
> for the force on a fixed atom, even though it experienced forces from
> the surrounding atoms. Looking at the code, this occurs because
> ibelly sets these values to zero. It looks like this task is not
> possible without changing the source code.

I agree: you would have modify the code to print out the forces before the
ibelly step sets them to zero. I'm pretty sure this has not changed in more
recent releasees.


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Received on Fri Dec 05 2008 - 18:28:45 PST
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