[gmx-users] constant pressure in NPT simulation

[Paul bauer]

Hello,

what do you mean with the pressure not being constant? If you mean the 
fluctuations in the instantaneous pressure, this is normal. What should 
be constant is the time average of the pressure over the time of the 
simulation.
I don't see anything particular in your mdp file that could cause the 
pressure coupling to fail.

Cheers

Paul

On 03/08/18 09:14, Lucia Mydlova wrote:
> Dear all customers.
>
> I have a problem, in my NPT simulations the pressure is not constant and
> the temperature is. Earlier simulation in NVT conditions was ok. I use
> these parameters:
>   tcoupl              =  nose-hoover
> tc_grps             =  system
> tau_t               =  0.002
> ref_t               =  500
> Pcoupl              =  parrinello-rahman
> pcoupltype          =  isotropic
> tau_p               =  1.0
> compressibility     =  4.5e-5
> ref_p               =  1.0
>
> What should I change in the .mpd file?
> Thank you very much.
> Lucia