[gmx-users] Re: Problem with pressure coupling

[Ondrej Marsalek]

On Wed, Sep 29, 2010 at 21:56, David van der Spoel <spoel at xray.bmc.uu.se> wrote:
>
>
> Now the differences in the tpr files are revealing:
> [anfinsen:test-volume-drift] % gmxcheck -s1 topol405.tpr -s2 topol.tpr
> <snip>
> Note: tpx file_version 58, software version 73
> Reading file topol.tpr, VERSION 4.5.1-%ci-21e8a32 (single precision)
> comparing inputrec
> inputrec->nstcalcenergy (1 - 10)
> inputrec->rgbradii (2.000000e+00 - 1.000000e+00)
> inputrec->sa_surface_tension (2.092000e+00 - 2.050160e+00)
> inputrec->sc_sigma_min (0.000000e+00 - 3.000000e-01)
> inputrec->nstdhdl (1 - 10)
> inputrec->separate_dhdl_file (0 - 10)
> <snip>
>
> After setting nstcalcenergy = 1 I get
> Density        996.894        1.2    3.85083    1.86718  (kg/m^3)
>
> In other words the bug can be circumvented by setting this variable to 1. I
> will file a bugzilla.
>

Thank you. The suggested workaround does indeed avoid the bug. For the
simulations that I need at the moment, having nstcalcenergy = 1 is not
a problem, as no extreme parallelization is needed. I would also like
to point out that, as I said before, setting nstlist > 0 also works
around the bug. Perhaps it will be useful in debugging.

Ondrej