[Wien] about optimize the hexagonal cell .the force is increasing.

[Laurence Marks]

As I said, the code works, let it do what it is supposed to do.

On 7/27/07, Mary White <us.white at yahoo.com> wrote:
> Dear Marks,
>      Thank you very much for your reply. If I don't modify the case.inM
> file, the forces finally may be too high. Then,can I use the optimized
> sturcture for the  following optimization or the calculation of band
> structure and so on?
>      Thanks again.
>
> Laurence Marks <L-marks at northwestern.edu> wrote:
>  The answer is to do nothing and just let PORT run WITHOUT changing the
> delta parameter. In fact, if you have changed it you have to restart
> the minimization (not the full calculation) by using "x pairhess" and
> copying .minpair to .minrestart and .min_hess. I suggest that you copy
> case.inM_st to case.inM as well. (Caveat, pairhess is not implimented
> for rhombohedral unit cells.)
>
> To explain, the code is minimizing the energy, not necessarily
> minimizing the forces. If you are far from the solution (which you are
> since your forces are high and the code gave you a warning about the
> curvature condition) it is perfectly physical for the forces to
> increase as the energy drops. Let the code handle this, in most cases
> it knows what it is doing better than you do!
>
> For more information see:
> http://www.wien2k.at/reg_user/textbooks/Optimization-Notes.pdf
> http://xxx.lanl.gov/abs/physics/0608160
> http://dx.doi.org/10.1016/j.commatsci.2007.01.004
>
> On 7/27/07, Mary White wrote:
> > Dear users,
> > I use PORT option to optimize the hexagonal structure including cell
> > parameters and atom position. But the force on an atom is too big ,as
> > follows.
> >
> > :FGL001: 1.ATOM -57.904000127 0.000000127
> > 0.000000000
> > :FGL001: 1.ATOM -59.863000131 0.000000131
> > 0.000000000
> > :FGL001: 1.ATOM -68.146000149 0.000000149
> > 0.000000000
> >
> > :FGL002: 2.ATOM -32.135000070 0.000000070
> > 0.000000000
> > :FGL002: 2.ATOM -31.330000068 0.000000068
> > 0.000000000
> > :FGL002: 2.ATOM -28.205000062 0.000000062
> > 0.000000000
> >
> > :ENE : ********** TOTAL ENERGY IN Ry = -158751.858644
> > :ENE : ********** TOTAL ENERGY IN Ry = -158751.860470
> > :ENE : ********** TOTAL ENERGY IN Ry = -158751.867677
> >
> >
> > The force on atom1 is increasing. I have decreased the delta in case.inM.
> > This file
> > is as follows:
> > PORT 2.0 0.20 # PORT/NEWT; tolf, Initial Trust Radius
> > 0.2 0.0 0.0 1.0 #Atom 1 Generated by pairhess
> > 0.2 0.0 0.0 1.0 #Atom 2 Generated by pairhess
> >
> > The force is still increasing. And
> > " :WARNING, CURVATURE CONDITION FAILED
> > :WARNING, S.Y WAS -1.050783136317473E-005
> > :WARNING, CURVATURE CONDITION FAILED
> > :WARNING, S.Y WAS -1.872153352633030E-004 " is appear.
> > I don't know how to deal with this case.
> > If any one know about this,please give some suggestion.Any comments will
> be
> > appreciated.
> > Thank you in advance.
> >
> > Mary
> >
> >
> >
> >
> > ________________________________
> > Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user
> panel
> > and lay it on us.
> >
> >
> > _______________________________________________
> > Wien mailing list
> > Wien at zeus.theochem.tuwien.ac.at
> > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> >
> >
>
>
> --
> Laurence Marks
> Department of Materials Science and Engineering
> MSE Rm 2036 Cook Hall
> 2220 N Campus Drive
> Northwestern University
> Evanston, IL 60208, USA
> Tel: (847) 491-3996 Fax: (847) 491-7820
> email: L-marks at northwestern dot edu
> Web: www.numis.northwestern.edu
> EMM2007 http://ns.crys.ras.ru/EMMM07/
> Commission on Electron Diffraction of IUCR
> www.numis.northwestern.edu/IUCR_CED
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
>
>
>  ________________________________
> Luggage? GPS? Comic books?
>  Check out fitting gifts for grads at Yahoo! Search.
>
>
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
>


-- 
Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2220 N Campus Drive
Northwestern University
Evanston, IL 60208, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
email: L-marks at northwestern dot edu
Web: www.numis.northwestern.edu
EMM2007 http://ns.crys.ras.ru/EMMM07/
Commission on Electron Diffraction of IUCR
www.numis.northwestern.edu/IUCR_CED