[gmx-developers] CVS implementation of REMD

[hessb at mpip-mainz.mpg.de]

Quoting Ken Rotondi <ksr at chemistry.umass.edu>:

> On May 25, 2005, at 11:19 AM, Anton Feenstra wrote:
> 
> > Ken Rotondi wrote:
> >> Then I ran mdrun:
> >> mdrun -v -multi -np 2 -replex 20 -s topol.tpr
> >
> > Perhaps -np 2 and -replex 20 'bite' each other. From what I gather 
> > from the other mails, 'mdrun -v -multi -replex 2' could work.
> >
> > -- 
> > Groetjes,
> >
> > Anton
> 
> This is rather confusing. I thought the -np flag was for the number of 
> processes running (i.e. the number of replicas in a REMD run) while the 
> -replex flag defines the number of integration steps that pass between 
> attempts at exchange.

Correct.

> 
> I'm still hopeful for insight into this problem and am re-posting the 
> question in response to several helpful suggestions:
> 
> Thanks for the suggestions. I'm probably doing more than two things 
> incorrectly...
> 
> Okay, I used grompp to generate sequentially numbered .tpr files using:
> 
> grompp -v -f 1.mdp -po 1out.mdp -c md8.gro -p p39a.top -o topol0.tpr
> 
> grompp -v -f 2.mdp -po 2out.mdp -c md8.gro -p p39a.top -o topol1.tpr
> 
> where 1.mdp and 2.mdp are .mdp files for adjacent temperatures in a 
> REMD analysis I am setting up.
> 
> Then I ran mdrun:
> 
> mdrun -v -multi -np 2 -replex 20 -s topol.tpr
> 
> Response?
> 
> Can not open file:
> topol.tpr

Strange.
This should work.
There has been a problem like this half year ago.
But in the current CVS this should work fine.
Many people use the CVS REMD code without problems.
Are you using recent CVS code?

Berk.


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