Re: [ESPResSo-devel] [bug #34476] virtual_sites_relative not working with some mesh based methods (maggs, lb)

[Axel Arnold]

On Tuesday 04 October 2011 17:06:14 Rudolf Weeber wrote:
>                  Summary: virtual_sites_relative not working with some mesh
> based methods (maggs,lb)
>
> When virtual sites cross the periodic boundaries, their position is not
> immediately folded and may therefore be outside the current box.
> Some mesh based alorighms don't handle this case.
> Folding the position of the virtual site immideately after placement, on
> the other hand, breaks the calculation of short range forces.

Hi!

All particles can cross the periodic boundaries a bit without immediately 
being folded, except if you choose skin=0. Any algorithm that enforces that 
will not scale to large computers, since it requires a particle exchange 
communication every time step. The solution is either to sort the particle 
positions or to use ghost frames in Maggs (same holds I think for the CPU-LB).

Axel

-- 
Dr. Axel Arnold Tel: +49 711 685 63593
ICP, Universität Stuttgart      Email: address@hidden
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70569 Stuttgart, Germany