Re: Constant pressure

From: Sebastian Stolzenberg (s.stolzenberg_at_gmail.com)
Date: Thu Nov 25 2010 - 13:04:51 CST

Happy Thanksgiving, Joyce,

it may be helpful, if you added the following to this namd thread:

1.)
actual system size?
2.)
What pressure outputs are you looking at?:
GPRESSURE, PRESSURE with or without AVG?

Regards,
Sebastian

On 11/25/10 11:29 AM, Kwee Hong wrote:
> Hi,
>
> I have my constant pressure control set as below during my
> equilibration stage:
>
> useGroupPressure yes
> useFlexibleCell no
> useConstantArea no
>
> langevinPiston on
>
> langevinPistonTarget 1.01325
> langevinPistonPeriod 100.
> langevinPistonDecay 50.
> langevinPistonTemp $temperature
>
> yet when I analyze my log file with NAMD plot, my pressure was found
> to fluctuate between -300 bar and 300 bar. Is this normal?
> When I read through the mailing list, someone says that this is caused
> by small size of the system. And another comments fluctuation of plus
> minus 50 bar is normal.
>
> please advice and thannks in advance.
>
> Regards,
> joyce
>
>

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