[Wien] Re: min force

[L. D. Marks]

Since the new mixer is "new", we don't know exactly what is "good" in all
cases yet. Comparing to some surface calculations I've been doing, :DIS
looks good, :PLANE OK. Check the variations in energy (:ENE) and ensure
that these are much smaller (at the end) than the differences in energy
between the different steps taken during the minimization (in
case.outputM). If they are not, then you will have a minimization problem.
What you can do is use a "Job.sh", and include in it more than one
command, for instance:

run_lapw -I -ec 0.00001
run_lapw -I -fc 1.0

I suspect that for big (e.g. surface) calculations it may be very hard to
minimize to much better than 1mRyd/a.u. in finite computer time -- and
probably not worth it (since experiments are never at T=0).

On Sat, 28 Aug 2004, Michael Gurnett wrote:

> is the following considered good or bad
>
> :DIS  :  CHARGE DISTANCE       0.0000171
> :PLANE:  INTERSTITAL DISTANCE  0.0001470
>
>
> Michael
>
> ----- Original Message -----
> From: "L. D. Marks" <L-marks at northwestern.edu>
> To: <wien at zeus.theochem.tuwien.ac.at>
> Sent: Saturday, August 28, 2004 2:51 AM
> Subject: Re: [Wien] Re: min force
>
>
> > On Thu, 26 Aug 2004, WANG YX wrote:
> >
> > > In order to get well converged and high-quality calculation, how should
> > > I do? Increase k-points? or increase R-MT*K-max?or some other option.
> >
> > The answer is "yes"; not very helpful I'm afraid. To minimize a structure
> > well you need to ensure that you have the charge within the atomic
> > spheres, the energy and (in the new mixer) the plane waves all well
> > converged. What you could do is use 'grep -e :ENE -e :DIS -e PLANE
> > case.scf' to check. You'll probably need to adjust the mixing to get a
> > well converged result, plus (perhaps) k-points, RKMAX etc. Maybe others
> > can give some specific suggestions; in my experience you have to do
> > "computer experiments" to determine the correct set of parameters for your
> > particular case.
> >
> > Remember, the brain is more powerful than the computer -- you'll need to
> > use it.
> >
> > -----------------------------------------------
> > Laurence Marks
> > Department of Materials Science and Engineering
> > MSE Rm 2036 Cook Hall
> > 2225 N Campus Drive
> > Northwestern University
> > Evanston, IL 60201, USA
> > Tel: (847) 491-3996 Fax: (847) 491-7820
> > mailto:L-marks at northwestern.edu
> > http://www.numis.northwestern.edu
> > -----------------------------------------------
> >
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> >
> >
>
>
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-----------------------------------------------
Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2225 N Campus Drive
Northwestern University
Evanston, IL 60201, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
mailto:L-marks at northwestern.edu
http://www.numis.northwestern.edu
-----------------------------------------------