[Pw_forum] Problem in phonon-5.0.2

[Lin, Yangzheng]

Many thanks. Yangzheng

On Thu, Sep 4, 2014 at 12:43 PM, Paolo Giannozzi <paolo.giannozzi at uniud.it>
wrote:

> >From the Doc/release-notes file:
> ===
> Fixed in 5.0.3 version:
> [...]
>    * PHonon: restart with convt=.true. was not working with PAW
>    * PHonon: in matdyn.x, displacement patterns were no longer correct
>      if eigenvectors of the dynamical matrix were also written to file
>    * PHonon: compatibility with files produced by previous releases
>      was broken if pools were used
>    * VERY NASTY PHonon bug: symmetry Sq=-q+G introduced in v.5.0.2
>      could lead to bad phonons in some cases and has been disabled
>    * PHonon: effective charges eu + PAW were not accurate with pools;
>      effective charges eu + US PP + spin-orbit nonmagnetic were not
>      working in parallel.
>
> I guess the "VERY NASTY PHonon bug" is the one you encountered.
> V.5.0.3 is very similar to v.5.0.2 so it shouldn't be difficult
> to adapt your codes built upon v.5.0.2
>
> P.
>
> On Thu, 2014-09-04 at 11:57 -0400, Lin, Yangzheng wrote:
> > Dear all QE users,
> >
> > Although phonon-5.1 is available now, I have to use phonon-5.0.2 for
> > some other codes I am using were built on phonon-5.0.2.
> >
> > Recently I found some problem that phonon-5.0.2 did not give the same
> > phonon frequencies as phonon-5.1 for some q points of my system. The
> > difference is big. For example,
> >
> > Phonon-5.1 gave
> >      q = (    0.000000000   0.000000000   0.053115094 )
> >
> **************************************************************************
> >      freq (    1) =       3.205949 [THz] =     106.938946 [cm-1]
> > but Phonon-5.0.2 gave
> >      q = (    0.000000000   0.000000000   0.053115094 )
> >
> **************************************************************************
> >      omega( 1) =      -7.856216 [THz] =    -262.055171 [cm-1]
> >
> > I found some codes in phonon-5.0.2 were modified by phonon-5.1 in
> > subroutine smallg_q (xq, modenum, at, bg, nrot, s, ftau, sym, minus_q)
> >
> >  phonon-5.0.2 used
> >      if (.not.minus_q) then
> >         raq = - raq
> >         minus_q = eqvect (raq, aq, zero, accep)
> >      endif
> >
> >  phonon-5.1 modified it as
> >      if (sym(irot).and..not.minus_q) then
> >         raq = - raq
> >         minus_q = eqvect (raq, aq, zero, accep)
> >      endif
> >
> > So I did this modification in phonon-5.0.2 and the modified
> > phonon-5.0.2 gave the same phonon frequencies as those from phonon-5.1
> > for the same q point.
> >
> > Since I have to continue use phonon-5.0.2 now, my question is does
> > anyone of you know if there were some other problems found in
> > phonon-5.0.2? Thanks.
> >
> > Sincerely,
> > Yangzheng Lin
> > Postdoctoral Associate
> > Geophysical Laboratory, Carnegie Institution for Science
> > 5251 Broad Branch Rd. NW, Washington, DC 20015, USA
> > _______________________________________________
> > Pw_forum mailing list
> > Pw_forum at pwscf.org
> > http://pwscf.org/mailman/listinfo/pw_forum
>
> --
>  Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
>  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
>



-- 
Yangzheng Lin
Postdoctoral Associate
Geophysical Laboratory, Carnegie Institution for Science
5251 Broad Branch Rd. NW, Washington, DC 20015, USA
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