AMBER Archive (2006)

Subject: Re: AMBER: Harmonic restraint along z-axis

From: David A. Case (
Date: Thu Jul 27 2006 - 09:32:52 CDT

On Wed, Jul 26, 2006, Myunggi Yi wrote:
> I'd like to restrain some atoms at a certain value (z=5.0) along
> the z-axis with a harmonic potential during simulations.
> The source code is so complicated for me.
> Would you give me some draft or orientation for adding
> my own potential to the sander code?

Look at subroutine xconst in $AMBERHOME/src/sander/ene.f. That shows you
how a general harmonic constraint is implemented and called. You could
modify this to have forces only along the z-direction.

...good luck...dac

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