[Pw_forum] split q for electron-phonon coupling calculations

[Dal Corso Andrea]

On Wed, 2010-10-06 at 10:25 +0200, Mithra Chan wrote:
> Hello, everyone,
> 
> I am trying splitting q points for electron-phonon coupling
> calculations on a computer cluster. Though jobs were finished after
> successful running, I was not given by file elph$qpoint . I did these
> calculations on example07 as follows:
> 1) a electronic scf calculation on a very dense k mesh with
> la2f=.true.,
> 2) a scf calculation on a medium k mesh without la2f,
> 3) split q point using following INPUT.
> 
> Electron-phonon coefficients for Al
>  &inputph
>   tr2_ph=1.0d-12,
>   prefix='al',
>   amass(1)=26.98,
>   outdir='$OUTDIR',
>   fildyn='al.dyn',
>   ldisp=.true.,
>   nq1=4, nq2=4, nq3=4
>   start_irr=0,
>   last_irr=0,
> /
> 
> 4) copy file $prefix.a2Fsave, $prefix.wfc*, $prefix.dyn0, and _ph0
> $prefix.phsave(including both data-file.xml and data-file.xml.$qpoint)
> to corresponding sub-job. Then a ph.x run for electron-phonon coupling
> using following INPUT.
> 
> phonons of al
>  &inputph
>   tr2_ph=1.0d-12,
>   nq1=4, nq2=4, nq3=4
>   amass(1)=26.98,
>   prefix='$prefix'
>   start_q=$i,
>   last_q=$i,
>   recover=.true.,
>   outdir='$INDIR/$i',
>   fildyn='$prefix.dyn',
>   fildvscf='$prefix.dv',
>   elph=.true.,
>   trans=.true.,
>   ldisp=.true.,
> /
> 
> 5) a run of ph.x by setting trans=.false.
> 
> Though the job runs successfully, it does not give me the file elph
> $qpoint. Having browsed the source code, the PH should produce files
> elph$qpoint when elph=.true.
> Any suggestion would be appreciated.
> 

The automatic split of the q points is not yet implemented for el-ph
calculation. So you cannot split the q points in this way. You have to
prepare many single q inputs of ph.x with ldisp=.false., giving the q
point in input.

Andrea

> Thanks a lot.
> 
> Mithra Chan
> 
> -- 
> Dr. Mithra Chan,
> Department of Physics, National University of Singapore, Singapore
> chan.mithra at gmail.com
> 
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-- 
Andrea Dal Corso                    Tel. 0039-040-3787428
SISSA, Via Bonomea 265              Fax. 0039-040-3787249
I-34136 Trieste (Italy)             e-mail: dalcorso at sissa.it