> > Hi all,
> > I have a couple of questions about restarting runs in NpT 
> > simulations with Parrinello-Rahman coupling.
> > 1) Which are the variables actually read from the .edr file for 
> > restarting, concerning the Parrinello-Rahman barostat?
> > 2) Would it be possible to "plug" arbitrary values of these 
> > variables in a .edr file? This could be needed, for example, if 
> > you want to exactly restart a run from a previous one, but you 
> > need to change the barostat variables. If this option is not 
> > already implemented in the tools suite of gromacs, it would 
> > require some hack of parts of the code, I guess. Any help would 
> > be really appreciated.
> > Thank you in advance and best regards,
> >
> >
> >
> The variables for Parrinello-Rahman in the energy file are the box
> velocities.
> 
> Exact restarts are there so that several shorter runs will give binary
> identical
> results to one long run. Or to exactly redo part of a run.
> When you change a barostat variable the concept of exact restarts does
> not apply.
> 
> Berk.
> 
> 

Thanks for your reply. In the previous message, I was misleading, though.
What I meant was the following: is it possible to produce an .edr
file with "arbitrary" box velocities? For example: I run an NpT simulation
(with Parrinello-Rahman barostat), I get an .edr file, and I want to
restart from this .edr file, but changing the box velocities with some
new values. Of course, this would be not useful for an "exact" restart 
from a previous run.
I'd need something like that for some time-reversibility tests (and not
for production runs); so, even a way to "hardcode" the new box velocities
into the .edr file or whatever "trick" wouldn't be a big problem.
Greetings,

Francesco

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