Re: Using TCLforces to rescale force(s) on particular atom(s) --- loadtotalforces, addforce and previous/current timestep issue

From: Boyang Wang (pkuwangboyang_at_gmail.com)
Date: Thu Jan 19 2012 - 17:45:41 CST

Hi Gungor,

I have a comment -- I would care more about how to calculate the force at
the next time step. It is like a wavepacket, and the historical information
of forces are stored in the eigenmodes of the system.

Best,
Boyang

On Fri, Jan 20, 2012 at 1:44 AM, Gungor Ozer <gungor_at_bu.edu> wrote:

> Dear all,
>
> I have been trying to adapt a TCL script that would use TCLforces to
> rescale force on specified atoms. The idea is simple:
>
> 1) Calculate current force on a particular atom, f ---
> (loadtotalforces)
> 2) Rescale it using some factor, x.
> 3) Add force, (x-1)*f --- (addforce)
>
> I was planning to do this using the built-in loadtotalforces and addforce
> commands. However, there is one issue: loadtotalforces reads the total
> forces on each requested atom in the "previous timestep" but addforce adds
> the force at the "current time step".
>
> Is there anyway to get around this? Any input will be helpful and greatly
> appreciated.
>
> Thanks in advance,
> Gungor
>

-- 
Boyang Wang, Ph.D.

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