[Pw_forum] GIPAW problems

[Prasenjit Ghosh]

In addition to Emine's response I would also like to mention that
occupations='fixed' is available only for calculations with a gamma
k-point. So for your case you need to use a supercell. Also when you do the
gamma-point calculations, set K_POINT{automatic} with 1  1 1 0 0 0 mesh
because gipaw does not work with the gamma-point specific subroutines.
At least this is the case for version 4.3.2. I do not know whether this has
been improved in 5.0

With regards,

Prasenjit

On 5 September 2012 21:51, Emine Kucukbenli <kucukben at sissa.it> wrote:

> Hi all,
> Just to update the forum:
> The problem mentioned in this thread has been solved by the use of
> occupations='fixed' instead of smearing methods.
> This might be a good time to remind interested users that the QE-GIPAW
> implementation is only for insulators for the time being. Although not
> always, but with some compilers, the unexpected insulator+smearing
> input configuration could give wrong results as we have seen here.
> Currently, Davide Ceresoli is updating the code to include metallic
> systems as well, with this development the mentioned 'bug' would no
> more appear starting from the next release.
> Thanks for your feedback!
> -
> emine kucukbenli
> postdoc, epfl, switzerland
>
>
> Quoting Zbigniew Lodziana <Zbigniew.Lodziana at ifj.edu.pl>:
>
> > Dear Forum Users & Developers,
> >
> > I am new in QE Forum - welcome to All & congratulations for excellent
> > information exchange here and software.
> >
> > Being new in GIPAW calculations I might have missed the answer browsing
> the
> > Forum but did not found solution yet.
> >
> > The problem is that I am somehow puzzled by GIPAW calculations:
> >
> > - Using QE 5.0 I did compile it with Intel Fortran, MKL, openmp (more
> details
> > below). No tuning, no tricks etc. just followed installation guide
> > (./configure &  make all).
> >
> > - While pw.x performs nicely, gipaw.x gives results that are difficult
> for
> > interpretation, and I cannot really locate where the problem is.
> >
> > - Both pw.x and gipaw.x pass self-test; examples were no problem too.
> >
> > However, trying to calculate NMR spectra for slightly complex system
> > calculations with GIPAW give results that seems to be machine
> > dependent to the
> > large extend.
> >
> > Input files and part of output are at the end; shortly "Total NMR
> chemical
> > shifts in ppm:" is either 16.58 or 134.05 for the same system/element
> (inputs
> > are simply copied) when calculated on two similar machines.
> >
> > Both computers are Intel based, compiler and libraries differ however:
> > a) intel 11.1 (ifort); mkl 10.3
> > b) intel 11.1 (ifort); mkl 10.2.5.035
> >
> > Playing with pseudopotentials, k-points make things even worse.., denser
> fft
> > grid, density cutoff does not seems to improve results either). I use
> several
> > other numerical codes on both machines - never had similar problems.
> >
> > I would highly appreciate any suggestions/help toward resolving this
> problem.
> >
> > best regards & thank you in advance,
> > Zibi
> >
> > Zbigniew Lodziana
> > Polish Academy of Sciences,
> > ul.. Radzikowskiego 152,
> > PL-31-342 Krakow
> > ====================================================================
>
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-- 
PRASENJIT GHOSH,
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