Re: [ESPResSo-users] Particle in Fluid, periodic boundary conditions

[Ulf Schiller]

Hi Joost, Markus, all,

after a quick inspection I can't see any relevant changes to the
coupling on that branch (I've not gone through the CUDA implementation
though). After merging and running the script Markus provided, I'm
afraid the issue persists. I don't have time to track this down, but
according to my experience it is likely to be due to one of the following:
- problem with pos-lattice mapping (less likely since only halo affected)
- halo not up-to-date
- forces missing in halo upon redef of fluid momentum

Note that this bug potentially affects any system with particle-fluid
coupling and periodic boundary conditions.

Cheers,
Ulf

On 28/11/14 15:27, Joost de Graaf wrote:
> Dear Markus,
> 
> Sorry about that. The ENGINE branch on hmenke's git account
> 
> https://github.com/hmenke/espresso/tree/engine
> 
> has a fix for the bug. As I said, I recalled seeing something like it,
> and at that time we apparently fixed the problem (which I cannot
> remember doing). We are still working on one last testcase for the
> ENGINE branch, before we have it pulled into the Master, which will take
> about a week. Then a lot of the LB bugs should be fixed.
> 
> Kind Regards, Joost
> 
> On 28 November 2014 at 16:24, Joost de Graaf <address@hidden
> <mailto:address@hidden>> wrote:
> 
>     Dear Markus,
> 
> 
> 
>     On 24 November 2014 at 21:24, Joost de Graaf
>     <address@hidden <mailto:address@hidden>> wrote:
> 
>         Dear Markus,
> 
>         I remember spotting something like this in one of the older
>         versions of the master, but I tried to find it and could not
>         reproduce the bug with the latest version, which one are you using?
> 
>         KR, Joost
> 
>         On 24 November 2014 at 19:35, Ulf Schiller <address@hidden
>         <mailto:address@hidden>> wrote:
> 
>             Hi Markus,
> 
>             On 24/11/14 18:12, Wink, Markus wrote:
>             > can explain it to me? It seems, that the periodic boundary 
> condition in
>             > the LB Fluid doesn’t work. If I remove the fluid I don’t see 
> that.
> 
>             Yes, looks like something is at odds with the periodicity
>             here. Can you
>             plot the z-velocity over x-position? That may point towards
>             what is
>             going wrong.
> 
>             Cheers,
>             Ulf

-- 
Dr Ulf D Schiller
Centre for Computational Science
University College London
20 Gordon Street
London WC1H 0AJ
United Kingdom

Phone: +44 (0)20 7679 5300

trajectory_raw.png
Description: PNG image