Re: [ESPResSo-users] Local box size for Espresso 3.2.0

[Axel Arnold]

Hi Vincent,

you need to set the box length before setting the dpd thermostat and 
interactions. At the time you set the dpd thermostat, you still have a 
box of size 1 1 1, which on 32 processors gives too small domains, as 
the error says.

In older versions, the dpd cutoff wasnt checked properly, that is why 
your script didn't break, but the correct behavior is the new one. Also 
in the old version, you never could set an interaction with a range 
larger than then local box length.

Cheers,
Axel

On 13.09.13 04:14, Vincent Ustach wrote:
> Hi All,
>
> I am having a problem with the current version of Espresso, 3.2.0. I 
> currently have a script with 2700 particles interacting via the DPD 
> thermostat. I have attached the script.
>
> When using version 3.1.1 the script runs with no problems. When using 
> version 3.2.0 with the same .tcl script I get the following error:
>
> background_errors 0 {013 box_l in direction 0 is too small} {013 box_l 
> in direction 1 is too small} {013 box_l in direction 2 is too small} 
> {002 interaction range 0.51225 in direction 0 is larger than the local 
> box size 0.25} {002 interaction range 0.51225 in direction 1 is larger 
> than the local box size 0.25} {002 interaction range 0.51225 in 
> direction 2 is larger than the local box size 0.5} {013 box_l in 
> direction 0 is too small} {013 box_l in direction 1 is too small} {013 
> box_l in direction 2 is too small} {002 interaction range 0.51225 in 
> direction 0 is larger than the local box size 0.25} {002 interaction 
> range 0.51225 in direction 1 is larger than the local box size 0.25} 
> {002 interaction range 0.51225 in direction 2 is larger than the local 
> box size 0.5} 1 <consent> 2 <consent> 3 <consent> 4 <consent> 5 
> <consent> 6 <consent> 7 <consent> 8 <consent> 9 <consent> 10 <consent> 
> 11 <consent> 12 <consent> 13 <consent> 14 <consent> 15 <consent> 16 
> <consent> 17 <consent> 18 <consent> 19 <consent> 20 <consent> 21 
> <consent> 22 <consent> 23 <consent> 24 <consent> 25 <consent> 26 
> <consent> 27 <consent> 28 <consent> 29 <consent> 30 <consent> 31 
> <consent>
>     while executing
> "thermostat dpd 1.0 1.0 0.11225"
>     (file "dpd.tcl" line 46)
>
> it looks like the script is setting the box size on its own. To 
> counter this I have included "setmd node_grid 4 4 2" for 32 processors 
> and this seems to have no effect.
>
> When the Lattice Boltzmann equation (lbfluid and thermostat LB) are 
> used, there are no problems that I can tell.
>
> Best Regards,
>
> --Vincent Ustach
>   University of California, Davis


--
JP Dr. Axel Arnold
ICP, Universität Stuttgart
Allmandring 3
70569 Stuttgart, Germany
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Tel: +49 711 685 67609