[gmx-users] average pressure of a system

[Dwey]

Hi All.

   I work on a simulation of a membrane protein in a model membrane
(DPPC) with a total of 26,859 atoms.  In a step of NPT equilibration,
my mdp file is used for a 100 ps NPT and it has a reference pressure
of 1 bar.

 At the end of simulation,  I obtained a result of the average
pressure of the system ( ~ -0.90 bar)  like

Energy                      Average   Err.Est.       RMSD  Tot-Drift
-------------------------------------------------------------------------------
Pressure                    -0.9049        2.6    186.304    13.8503  (bar)


I am wondering if  I should keep running this NPT process until the
average pressure of the system reaches ~ 1.0 bar.

If so, how long ( how many steps) ?

Or should I modify mdp file  ? Can anyone provide some suggestions ?


Likewise, at the end of Production MD for 1 ns, I obtained  average
pressure (~2.23 bar)  of the system like

Energy                      Average   Err.Est.       RMSD  Tot-Drift
-------------------------------------------------------------------------------
Pressure                    2.23349        2.1     164.97    10.9381  (bar)

Should I run a longer simulation until the average pressure reaches ~
1.0 bar,  although average energy, average temperature (323 K),
average density (1022 kg/m^3) are already at  the desired values ?

How should I do to stabilize average pressure  at a desired value (~1 bar) ?


Thanks for any input.
Dwey