[gmx-users] Pressure variation in NPT ensemble
Mark.Abraham at anu.edu.au
Thu Dec 14 05:27:20 CET 2006
nur avneet wrote:
> Dear all
> I set the pressure in NPT ensemble to 1bar..and run the simulation.
> But, the log file does not show the same pressure...for some cases it
> does remain close to 1 but in others it even shows around 4 bars of
> What is the significance of this variation...and what should i do to
> remaove this variation.
This gets "reported" every few months on this list. You are not
"setting" the pressure to 1bar, you are specifying a negative-feedback
system to move the system towards 1bar. The variation is normal and not
indicative of a problem unless the time-average of that value is not
near the chosen value.
Think about how you might define an instantaneous pressure in
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