[Pw_forum] Iron cluster relaxation

[Cyrille Barreteau]

Dear Kostya and Axel

I have restarted my job with the last coordinates and
the geometry optimization converged in just one scf cycle!!

==========================================================
     BFGS Geometry Optimization

     bfgs converged in   1 scf cycles and   0 bfgs steps

     End of BFGS Geometry Optimization
=============================================
So I guess the previous "crashed run" did converge correctely
toward the right optimal atomic configuration!!

thanks

    cyrille

>On Fri, 10 Nov 2006, Konstantin Kudin wrote:
>
>kostya,
>
>KK>  It is not clear why the job should have a hard crash like this instead
>KK> of either terminating gracefully, recovering from the condition in some
>KK> way, or at least printing the very thing that you say, i.e. that
>KK> "optimization terminated due to noise in the forces, increase cutoff",
>KK> or something else similar.
>
>i agree. after this issue has come up quite a few times 
>in the last months, it may be worth putting in the effort
>and changing the code, so that it a) exits gracefully,
>b) has a few more options on how to handle the resets,
>e.g. force a minimum number of steps between two resets,
>or have a small(!) randomization of coordinates.
>
>that just leaves the usual problem: who is going to do it?
>anybody in the market for making a lot of people happy?
>
>KK>  Actually, in my experience just restarting the job with the last
>KK> coordinates has a very good chance to advance further, and even find a
>KK> lower energy structure since the BFGS will be started from scratch.
>
>hmmm. if you see the latter, then perhaps the reset is not
>a complete reset and there may be a bug (unless you have
>a 'randomization' of the coordinates due to limited
>accuracy when reading in the so far optimized coordinates).
>
>cheers,
>   axel.
>
>KK> 
>KK>  Kostya
>KK> 
>KK> 
>KK> 
>KK> --- Axel Kohlmeyer <akohlmey at cmm.chem.upenn.edu> wrote:
>KK> 
>KK> > On Fri, 10 Nov 2006, Cyrille Barreteau wrote:
>KK> > 
>KK> > CB> Dear Pwscf users
>KK> > 
>KK> > dear cyrille,
>KK> > 
>KK> > did you check the mailing list archives?
>KK> > 
>KK> > IIRC, this error seems to happen if you try to
>KK> > optimize the geometry too tightly for the
>KK> > given convergence of the wavefunction or
>KK> > when you suffer from 'ripples' due to a
>KK> > too small density cutoff.
>KK> > 
>KK> > salut,
>KK> >   axel.
>KK> > 
>KK> > CB> I am trying to relax an iron cluster (cubocathedron) and
>KK> > CB> pw.x systematicaly ends with the following error:
>KK> > CB> 
>KK> > CB> 
>KK> >
>KK> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>KK> > CB>      from bfgs : error #         1
>KK> > CB>      bfgs history already reset at previous step
>KK> > CB> 
>KK> >
>KK> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>KK> > CB> 
>KK> > CB>      stopping ...
>KK> > CB> 2
>KK> > CB> 
>KK> > CB> 
>KK> > CB> You can find the input and output files on the following web
>KK> > site:
>KK> > CB> 
>KK> > CB>
>KK> >
>KK> http://www-drecam.cea.fr/Images/Pisp/cbarreteau/temporaire/cuboctahedron_relax.in
>KK> > CB>
>KK> >
>KK> http://www-drecam.cea.fr/Images/Pisp/cbarreteau/temporaire/cuboctahedron_relax.out
>KK> > CB> 
>KK> > CB> 
>KK> > CB> thanks in advance for any constructive comment :-)
>KK> > CB> 
>KK> > CB>    cyrille
>KK> > CB> 
>KK> > CB> 
>KK> > 
>KK> > -- 
>KK> >
>KK> =======================================================================
>KK> > Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu  
>KK> > http://www.cmm.upenn.edu
>KK> >    Center for Molecular Modeling   --   University of Pennsylvania
>KK> > Department of Chemistry, 231 S.34th Street, Philadelphia, PA
>KK> > 19104-6323
>KK> > tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel:
>KK> > 1-215-898-5425
>KK> >
>KK> =======================================================================
>KK> > If you make something idiot-proof, the universe creates a better
>KK> > idiot.
>KK> > 
>KK> > _______________________________________________
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>KK> > Pw_forum at pwscf.org
>KK> > http://www.democritos.it/mailman/listinfo/pw_forum
>KK> > 
>KK> 
>KK> 
>KK> 
>KK>  
>KK> ____________________________________________________________________________________
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>KK> 
>
>  
>


-- 
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Cyrille Barreteau

CEA Saclay DSM/DRECAM/SPCSI

Batiment 462

91191 Gif sur Yvette Cedex FRANCE
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phone : +33 (0)1 69 08 29 51
fax : +33 (0)1 69 08 84 46
email : cyrille.barreteau at cea.fr

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http://www-drecam.cea.fr/Images/Pisp/cbarreteau/cbarreteau_fr.html

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