Re: [ESPResSo-users] time dependent force

[Jiajia Zhou]

I mean if I use "integrate 1", then the forces have to be calculated
before the first step of vv scheme and also at the third step.

The potential I used is just a sinusoidal potential. I am running some
tests right now. If they are fine then I will be happy to send the
relative codes.

Thanks for your help!
Jiajia

On Wed, Jul 20, 2011 at 5:35 PM, Axel Arnold
<address@hidden> wrote:
> On Wednesday 20 July 2011 16:02:41 Jiajia Zhou wrote:
>> Thanks for the reply. I would like to change the force every single
>> time step. To do this in the tcl level, I think the force are
>> calculated twice for every time step (am I correct?), so I can save
>> some time by implementing in the c level.
>
> Hi,
>
> no, the forces are normally calculated only once per time step, but twice used
> in the propagation. Nevertheless, if you have e.g. a periodically oscillating
> force, you definitely want to implement it as an constraint.
>
> Btw, if your external potential is not very exotic, such as e.g. a simple
> sinusoidal potential sin(kx + wt) or so, it would be nice if you could send us
> the code for integration with the next release, since that might be of general
> interest.
>
> Axel
>
> --
> JP Dr. Axel Arnold
> ICP, Universität Stuttgart
> Pfaffenwaldring 27
> 70569 Stuttgart, Germany
> Email: address@hidden
> Tel: +49 711 685 67609
>
>