[gmx-developers] electrostatic forces and domain decomposition

[Dommert Florian]

On Sun, 2011-06-26 at 08:45 -0400, Roland Schulz wrote:
> Hi,
> 
> On Sun, Jun 26, 2011 at 8:31 AM, Dommert Florian
> <dommert at icp.uni-stuttgart.de> wrote:
>         with the current release-4-5-patches branch unexpected large
>         electrostatic forces arise when using PME and MPI in
>         combination with domain decomposition. I tried to attach a
>         small test case with a water box of about 4000 molecules and a
>         corresponding mdp, top, itp, and gro file, but it was too
>         large. For particle decomposition
>         with different numbers of processes everything is fine as well
>         as for a
>         run with a single process and DD. However using multiple
>         processes and
>         DD I obtain forces around 10^10, though they should be around
>         10^3.
>         
>         For the testruns I compiled gromacs with cmake on a
>         Ubuntu 10.4 platform with a 2.6.39-rc6+ kernel using gcc4.4.3
>         and
>         OpenMPI 1.4.3 and fftw3.2.2
>         and a Rocks Cluster with a 2.6.18-164.6.1.el5 kernel and the
>         same
>         compiler, MPI and fftw3 version. On both systems I obtain the
>         strange
>         behaviour.
>         
>         When I got back to the commit with SHA1 ID
>         e5eb052ebf35e4b778f7a3908463a68a2ef6faee, merge by merge,
>         everything is fine again. 
> 
> 
> What do you mean merge by merge? Could you do a git bisect?

Hello,

after bisecting the release-4-5-patches branches, git tracked down the
error to commit:

[68ab9f6fa143fec070ffe60686cb8f9e397d0376] Expanded LINCS warning text

Is this what you asked me to do ?

/Flo 
> 
> 
> Roland 
>         
>         
>         /Flo
>         --
>         Florian Dommert
>         Dipl. - Phys.
>         
>         Institute for Computational Physics
>         University Stuttgart
>         
>         Pfaffenwaldring 27
>         70569 Stuttgart
>         
>         EMail: dommert at icp.uni-stuttgart.de
>         Homepage: http://www.icp.uni-stuttgart.de/~icp/Florian_Dommert
>         
>         Tel.: +49 - (0)711 - 68563613
>         Fax.: +49 - (0)711 - 68563658
>         
> 
> 
> 
> -- 
> ORNL/UT Center for Molecular Biophysics cmb.ornl.gov
> 865-241-1537, ORNL PO BOX 2008 MS6309
> 
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-- 
Florian Dommert
Dipl. - Phys.

Institute for Computational Physics
University Stuttgart

Pfaffenwaldring 27
70569 Stuttgart

EMail: dommert at icp.uni-stuttgart.de
Homepage: http://www.icp.uni-stuttgart.de/~icp/Florian_Dommert

Tel.: +49 - (0)711 - 68563613
Fax.: +49 - (0)711 - 68563658
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