[gmx-users] box size changing during isotropic pressure coupling

[chris.neale at utoronto.ca]

A knowledgeable and helpful gromacs user has pointed me to some  
bugzilla comments: http://bugzilla.gromacs.org/show_bug.cgi?id=165  
that reference revision comments:  
http://www.gromacs.org/gromacs/revisions/

Berk Hess
13 Feb 2008
box distortion with pressure coupling

In all Gromacs versions before 4 the box shape would "diffuse" over  
time when using (semi)isotropic pressure coupling. This issue (only  
noticable for very long simulations) has been fixed for version 4.0.

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This sounds like the source of the problem that I outlined earlier. I  
wonder if anybody can expand upon the exact nature of the bug so that  
I can make the necessary increases in my error bars or otherwise  
compensate for the bias that may have resulted from this effect?

Thanks,
Chris.