[Pw_forum] Symmetry recognition

[Paolo Giannozzi]

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
>
>
>
>
>
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-- 
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