[gmx-developers] freeenergy.relative unstable?

[Shirts, Michael (mrs5pt)]

Given the fact the potential generally doesn't diverge immediately, and
these code changes involve changes in the order of operation of the
calculations, I would expect it's probably a numerical instability issue. I
can have a look at this case more carefully as we get ready for 5.0.

Best, 
~~~~~~~~~~~~
Michael Shirts
Assistant Professor
Department of Chemical Engineering
University of Virginia
michael.shirts at virginia.edu
(434)-243-1821


> From: Szilárd Páll <pall.szilard at gmail.com>
> Reply-To: Discussion list for GROMACS development <gmx-developers at gromacs.org>
> Date: Fri, 18 Oct 2013 20:12:35 +0200
> To: Discussion list for GROMACS development <gmx-developers at gromacs.org>
> Subject: [gmx-developers] freeenergy.relative unstable?
> 
> Hi,
> 
> The freeenergy.relative test has been failing on a regular basis, some
> of the recent cases are:
> http://jenkins.gromacs.org/job/Gromacs_Gerrit_4_6/4008/
> http://jenkins.gromacs.org/job/Gromacs_Gerrit_4_6/4014/
> http://jenkins.gromacs.org/job/Gromacs_Gerrit_4_6/4019/
> http://jenkins.gromacs.org/job/Gromacs_Gerrit_4_6/4064/
> http://jenkins.gromacs.org/job/Gromacs_Gerrit_4_6/4084/
> http://jenkins.gromacs.org/job/Gromacs_Gerrit_4_6/4095/
> 
> Based on these the failure seems to occur more often on the Sandy
> Bridge test machine (and 4/5 with gcc 4.8).
> 
> Is there any concern that there may be a slight bug present or can we
> safely blame this on the instability of this particular test?
> 
> Cheers,
> --
> Szilárd
> -- 
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