[Pw_forum] Symmetry recognition

[Pascal Boulet]

Dear all,

Thank you for your answers. I am trying to reproduce it with a smaller system… I indeed restart from an incomplete calculation. 

Pascal



Le 23 févr. 2017 à 21:45, Paolo Giannozzi <p.giannozzi at gmail.com> a écrit :

> Of course there is a reason, but not necessarily a good one. If you
> are "restarting from an incomplete calculation", I guess that the code
> overwrites the input coordinates with the current ones. The symmetry
> should be the same, but sometimes numerical noise breaks the symmetry.
> It is impossible to say more without an example.
> 
> Paolo
> 
> On Thu, Feb 23, 2017 at 8:56 AM, Pascal Boulet
> <pascal.boulet at univ-amu.fr> wrote:
>> Dear all,
>> 
>> I am running a structural optimization with QE 6.0. The structure is
>> orthorhombic, ibrav=8, with 8 symmetry elements. The first run did not
>> converge so I have to restart it. But as I restart it, the number of
>> symmetry is now 4, there is a descent of symmetry. I shall say that I use
>> the space_group option with COORDINATES crystal_sg. But the problem remains
>> if I put all the coordinates (unsurprisingly).
>> 
>> Is there a reason for this, and can I avoid this?
>> 
>> Thank you
>> Best regards
>> Pascal
>> 
>> -
>> Pascal Boulet - MCF HDR, Resp. L2 MPCI - DEPARTEMENT CHIMIE
>> Aix-Marseille Université - ST JEROME - Avenue Escadrille Normandie Niemen -
>> 13013 Marseille
>> Tél: +33(0)4 13 55 18 10 - Fax : +33(0)4 13 55 18 50
>> Site : http://madirel.univ-amu.fr/pages_web_BOULET_PASCAL/annuaire - Email :
>> pascal.boulet at univ-amu.fr
>> 
>> 
>> 
>> 
>> 
>> _______________________________________________
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://pwscf.org/mailman/listinfo/pw_forum
> 
> 
> 
> -- 
> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
> 
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum