Re: only minimization

From: Ravinder Abrol (abrol_at_wag.caltech.edu)
Date: Fri Feb 24 2006 - 12:59:52 CST

Hi Lewyn,
The PDF link:

> www.orgitecture.com/folding/usr_doc/PracticalMD.pdf

asks for a Document Open Password.
Do you know what that is?
Thanks,
Ravi

------------------------------------
On Fri, 24 Feb 2006, LEWYN LI wrote:

> Lily,
>
> Accordingly to my experience, you need to both minimize and
> equilibrate the system before running a NAMD simulation. The temperature
> of the system after a minimization is zero. So, if you just run a
> simulation of a zero-temperature system at any finite temperature, the
> system may become unstable. I suspect this is why you got the "Atom
> moving too fast" error message.
>
> To equilibrate a system after minimization, you should gradually
> heat the system up to the desired temperature, sometimes fixing certain
> atoms or imposing so-called "harmonic constraints" on the system. It is a
> bit of an art. I suggest that you consult the following and other
> resources about equilibration:
>
> www.orgitecture.com/folding/usr_doc/PracticalMD.pdf
>
> Hope this helps!
>
>
> LEWYN
>
>
> On Thu, 23 Feb 2006, lily jin wrote:
>
> > I am a new user a NAMD. Here is my problem:
> >
> > I tried to do only energy minimization with NAMD. So I let it do
> > minimization for 500000 timesteps. Then I let it run 1 step (or 10
> > steps). I was done with this start run. Then I tried to test if I can
> > restart from step 500000, but I keep having the problem of "Atom moving
> > too fast; simulation has become unstable" in my restart run.
> >
> > So I submit another job, where I let the minization go 500000 steps
> > and then run 1000000 step. It run well. As it went to step 587000, I
> > stopped it. After I made a restart file from step 587000. This time the
> > restart run worked!
> >
> > So how can I only do energy minimization with NAMD? How can I restart
> > from the last step of minimization?
> >
> > thank you!
> >
> >
> >
> >
> > Lily
> >
> > ---------------------------------
> > Yahoo! Mail
> > Use Photomail to share photos without annoying attachments.
>

-- 
________________________________________________
 Ravinder Abrol
 139-74, Beckman Institute
 Division of Chemistry and Chemical Engineering
 Caltech, Pasadena, CA 91125
 Phone: 1.626.395.8143
   Fax: 1.626.585.0917
 Email: abrol_at_wag.caltech.edu
________________________________________________

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