Re: [ESPResSo-users] Verlet list and LB

[Owen Hickey]

Hey Hender,

Yes, the GPU version is able to handle skins greater than half the
grid size. The reason for this is that currently the GPU only works on
a single GPU and thus their are no ghost particles (this may change in
the future). The CPU version is made for multiple processors and
particles on the edge of two domains need to be on both nodes. This is
done through the use of ghost particles on one of the nodes. This is
only possible if the skin is less than half the grid size. I am a bit
curious about your parameters. Typically one would set the grid size
to 1 and the skin to 0.3 which would work with both versions.

Kind regards,
Owen

On Fri, Sep 26, 2014 at 2:02 PM, Hender Lopez <address@hidden> wrote:
> Dear all,
>
> I am running some sims with a LB thermostat and if I use the CPU
> version (espresso-3.2.0 and espresso-3.3.0) I get the following error:
>
> background_errors 0 {104 LB requires either no Verlet lists or that
> the skin of the verlet list to be less than half of lattice-Boltzmann
> grid spacing.}
>
> Now if I use a skin greater that half of lattice-Boltzmann grid
> spacing with the GPU LB version the programs runs without any problem
> (again for both versions of espresso). My question is: is this OK , is
> the GPU version able to handle a skin greater that half of
> lattice-Boltzmann grid?
>
> Best,
>
> Hender
>