[QE-developers] Finding all symmetry operations correctly

[Paolo Giannozzi]

Hi, there is nothing to be sorry about: this problem was mentioned IN A
PRIVATE CONVERSATION. Thank to you for reporting it ("repetita iuvant" ==
"repetitions help", according to ancient Romans)

Paolo

On Fri, May 22, 2020 at 6:38 PM 박민규 <minkyupark at ulsan.ac.kr> wrote:

> Let me explain again.
>
> Given magnetic space group of MnF2 in its antiferromagnetic phase
> is P4_2’/mnm’ (136.499),
> there should be 16 symmetry operations if QE can detect all symmetry
> operations.
> While if you see pwscf.out.afm I attach, there are only 8 symmetry
> operations.
> (I’m only counting the number of operations, but each operations should be
> identified correctly after all.)
> This is the problem I have.
>
> I think this is a limitation that has been noticed and discussed recently.
> It shouldn't be too difficult to fix actually
>
>
> If this is the case, sorry for repeating this.
>
> Best,
> ============================================
> Minkyu Park
> Research Institute of Basic Sciences, University of Ulsan,
> 93, Daehak-ro, Nam-gu, Ulsan, 44610 Republic of Korea
> minkyupark at ulsan.ac.kr
> +82-52-259-1473
> ============================================
>
> On 23 May 2020, at 1:22 AM, 박민규 <minkyupark at ulsan.ac.kr> wrote:
>
> well yes this is the way you specify that the two atoms should be treated
> as different... (for instance because of different starting magnetizations
> in and anti-ferromagnetic  configuration)
>
> My original point was this.
> For an antiferromagnetic configuration with non-symmorphic space group,
> QE does not recognize part of symmetry operations.
>
> ============================================
> Minkyu Park
> Research Institute of Basic Sciences, University of Ulsan,
> 93, Daehak-ro, Nam-gu, Ulsan, 44610 Republic of Korea
> minkyupark at ulsan.ac.kr
> +82-52-259-1473
> ============================================
>
> On 23 May 2020, at 1:12 AM, Stefano de Gironcoli <degironc at sissa.it>
> wrote:
>
> well yes this is the way you specify that the two atoms should be treated
> as different... (for instance because of different starting magnetizations
> in and anti-ferromagnetic  configuration)
>
> why would anyone define two atoms of the same species as different types
> otherwise ?
>
> stefano
> On 22/05/20 18:02, 박민규 wrote:
>
> Dear all,
>
> Sorry for the insufficient information.
>
> I performed two calculations one is with one type of Mn and the other is
> with two type of Mn.
> Both of them are done without magnetic moments with relativistic
> pseudopotentials.
> With one type of Mn, I get 16 operations. While with two types of Mn, I
> get 8 operations.
> I attach input and output files.
>
> Best,
> ============================================
> Minkyu Park
> Research Institute of Basic Sciences, University of Ulsan,
> 93, Daehak-ro, Nam-gu, Ulsan, 44610 Republic of Korea
> minkyupark at ulsan.ac.kr
> +82-52-259-1473
> ============================================
>
> On 23 May 2020, at 12:47 AM, Lorenzo Paulatto <paulatz at gmail.com> wrote:
>
> I think the problem occurs because QE treats each type of atom (ntyp)
> differently even though they are actually same species.
>
>
>
> Hello Minkyu, QE always consider all atoms of the same species equivalent,
> unless you tell it explicitly not to. I think you should provide a
> reproducible example if you think there is a real bug. You can do it here,
> or on the gitlab bug tracker.
>
> regards
>
>
>
> --
> Lorenzo Paulatto - Paris
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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
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