[Pw_forum] Order of the q in the star for each dyn files
samuel.pon at gmail.com
Sat Jun 6 19:09:33 CEST 2015
The q2qstar should give the same order but it does not.
Actually there is more than the order. The signs can be different.
For example I get
0.5 0.5 0.5 in the sxq variable of the phonon code and -0.5 -0.5 -0.5 in
the sxq variable of the q2qstar code.
I know that it is the same point in diamond but this can leads to problems,
especially when the crystal does not respect time reversal (maybe in that
case the code produce the same result, I did not test).
Additionally, it does not really make sense that they produce different
My scf.in input is
calculation = 'scf'
prefix = 'diam'
restart_mode = 'from_scratch'
wf_collect = .false.
pseudo_dir = '../../pp'
outdir = './'
tprnfor = .true.
tstress = .true.
ibrav = 2
celldm(1) = 6.64245
nat = 2
ntyp = 1
ecutwfc = 40
nbnd = 4
diagonalization = 'david'
mixing_beta = 0.7
conv_thr = 1.0d-10
C 12.01078 C.UPF
C 0.00 0.00 0.00
C 0.25 0.25 0.25
4 4 4 1 1 1
My ph.in input is
prefix = 'diam',
epsil = .true.,
fildyn = 'diam.dyn',
ldisp = .true.
fildvscf = 'dvscf'
tr2_ph = 1.0d-12,
Department of Materials, University of Oxford
2015-06-05 21:57 GMT+01:00 Lorenzo Paulatto <lorenzo.paulatto at impmc.upmc.fr>
> On 05/06/15 22:26, Samuel Poncé wrote:
> > Dear all,
> > I'm a bit confused by the ordering of the q points that belong to the
> > star of a q-point.
> Dear Samuel,
> the order is not important, if for some reason you need a specific order
> your code is going to break sooner or later.
> Anyway, q2qstar uses the same subroutines as phonon, so in principle it
> should give the same order. If you have a valid reason for requiring the
> same order and if you provide enough input and example files to
> reproduce your case, I may have a look.
> > --
> > Dr. Lorenzo Paulatto
> > IdR @ IMPMC -- CNRS & Université Paris 6
> > +33 (0)1 44 275 084 / skype: paulatz
> > http://www-int.impmc.upmc.fr/~paulatto/
> > 23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05
> Pw_forum mailing list
> Pw_forum at pwscf.org
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