AMBER Archive (2002)

Subject: Re: ntx=7, irest=0, redux

From: David Case (case_at_scripps.edu)
Date: Sat Nov 23 2002 - 00:53:37 CST

On Fri, Nov 22, 2002, David A. Case wrote:
>
> > If I use ntx=7, irest=0,
> > will this ignore the velocities in the input file (restrt)
> > and generate new velocities ?
>
> Yes, this will generate randomized velocities, using the input values
> of tempi (to the initial temperature) and ig (to determine which pseudo-random
> sequence of numbers to use.)
>

Well, the above is what the code *should* do, but it looks in fact like
it is not what the code actually does. If you want to restart a periodic
system with randomized velocities, it looks like you have to manually edit
the restrt file to remove the velocities (but not the box info at the
bottom), then set ntx=1, irest=0.

According to the manual, setting vrand=-1 should also do the trick (with
no file editing required) but I have not tried this myself.

...dac 

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David A. Case                     |  e-mail:      case_at_scripps.edu
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