Re: [ESPResSo-users] ERROR: Interaction range is larger than the local box size

[Rudolf Weeber]

Hi Clemens,
On Tue, May 01, 2018 at 01:22:26PM +0200, Clemens Jochum wrote:
> Dear all,
> 
> I recently updated to the newest development version of ESPResSo and now
> my script returns an error when initializing the electrostatic
> interaction via P3M method.
> 
> My line of code:
> p3m = P3M(prefactor = sysParams['electrostatics']['preFactor'], accuracy
> = simParams['P3M']['accuracy'], r_cut = simParams['P3M']['r_cut'], mesh
> = simParams['P3M']['mesh'], tune = True)
> 
> Returned error:
> ERROR: box_l in direction 0 is too small
> ERROR: box_l in direction 1 is too small
> ERROR: box_l in direction 2 is too small
> ERROR: interaction range 316.923 in direction 0 is larger than the local
> box size 309.423
> ERROR: interaction range 316.923 in direction 1 is larger than the local
> box size 309.423
> ERROR: interaction range 316.923 in direction 2 is larger than the local
> box size 309.423
> 
> Is there a way to avoid this problem without reducing the number of
> nodes ( and thus increasing the local box size?)
You provide a fixed r_cut and mesh to the p3m, so it has no choice about the 
cutoff of the short range electrostaic part. If you leave those two out, it may 
be possible to tune to other parameters (higher mesh, cao) with a shorter real 
spcae cutoff, yielding the same accuracy.

Regards, Rudolf