# [gmx-developers] pV term calculated incorrectly

Mark Abraham Mark.Abraham at anu.edu.au
Mon Nov 30 02:33:02 CET 2009

David van der Spoel wrote:
> Michael Shirts wrote:
>> I noticed that the pV term stored in the mdebin when a NPT simulation
>> is performed is calculated incorrectly -- it uses the instantaneous
>> pressure, when it should be using the applied pressure.  dU = pdV, so
>> with constant p, U = \int p dV = p \int dV = pV
>>
>> I've written a fix (with full generality for arbitrary stress/strain),
>> but have realized I'm not exactly sure which branches I should be
>> checking into, and can't figure out exactly which git command I should
>> be using from the gromacs web page.  Any hints?
>>
>> Best,
>> Michael
> I'm not sure that anyone is using it, but thanks for fixing. In
> principle it is sufficient if it goes in the master branch I would think.

I've observed lots of such fixes being committed into both
release-4-0-patches and master, and that looks like a quite sensible policy.

Mark