Re: [ESPResSo-devel] Implementing Lowe-Andersen thermostat

[Axel Arnold]

Hi Kai,

Did you consider that In the C-core velocities are scaled by the time step?

Axel

Dr. Axel Arnold
Email: address@hidden

> Am 27.02.2015 um 23:39 schrieb Kai Szuttor <address@hidden>:
> 
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> Hi everyone,
> 
> currently i´m trying to implement the Lowe-Andersen thermostat (C. P.
> Lowe 1999 Europhys. Lett. 47 145 doi:10.1209/epl/i1999-00365-x) in the
> Espresso source code and having some issues i wasn´t able to resolve.
> So far i wrote a function that performs the thermalization of the
> particles relative velocities. This function is called by the function
> "integrate_vv" in integrate.cpp just after the GHMC thermostat is
> doing its ghmc_momentum_update()-call. I thought that would a good
> idea since the Lowe-Andersen thermostat is also only changing
> particles velocities and not the forces acting on them.
> The problem i'm having now is that the energy grows to infinity and i
> was not able to find out why.
> To check for the algorithm itself i implemented the thermostat on the
> tcl-level and it seems to work, so the algorithm itself should do the
> right thing.
> Is there anything i should know about espressos internal structure
> regarding the velocity handling? Maybe someone can give me a hint.
> 
> Thanks in advance.
> 
> Kai Szuttor
> Insitute for Computational Physics
> University of Stuttgart
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