[Wannier] Dissimilar results in band structures for a system obtained from Wannier90

Nicola Marzari nicola.marzari at epfl.ch
Mon Jun 15 14:17:23 CEST 2015


Thanks.

At first sight the two espresso codes give the same eigenvalues in the nscf,
but being run with two different parallelization choices, the
phases of the wannier functions will all be different, so
it's like dealing with two independent calculations. So the question is
for Wannier - to see if you have converged to the correct localized state,
or not. Usually, if the projections are correct, it shouldn't matter, but
maybe in this case they are not correct, and hten the codes randomly
converges, or not.

One of the outputs records a large imaginary part - that's a bad sign.
The other has two much less localized wavefunctions - maybe good, maybe
bad.

Can you try with projections that have a s orbital at every atom, and
a s orbital at every bond? Those should work, and it would be nice
to see that both codes give the same results.

Otherwise, we'll need to dig deeper.

			nicola




On 15/06/2015 13:41, Seyed Mojtaba Rezaei Sani wrote:
> Hi Nicola
>
> Thanks a lot for your kind response. Surely I did checked outputs before
> too. There was no considerable difference between them and also there is
> no unconverged band message. So I can say:
>
> Re 1) Every thing works perfectly both in 5.1 and 5.1.2 versions except
> the disappointing obtained wannier90 band structure by the later.
> Re 2) No difference.
>
> As more details, please find all in/output files for both versions
> (except UNK ones which are too big) here:
>
> https://www.dropbox.com/sh/xhd3etb6zfz2e7c/AAClTpe-aGkwXVrzDcIq6L7Aa?dl=0
>
> Thanks again,
>
> On Mon, Jun 15, 2015 at 12:23 PM, Nicola Marzari <nicola.marzari at epfl.ch
> <mailto:nicola.marzari at epfl.ch>> wrote:
>
>
>
>     Hi Sani,
>
>
>     I had mentioned in my email that you should check both
>     your input and your output files - since the problems seem due
>     to the change in version of quantum-espresso (I do appreciate you
>     did check your input files, but I do wonder why you didn't
>     read the email in full, since it was asking about the output).
>
>     So - do you see any difference in the output files of quantum espresso?
>
>      From your plots my first guess would be that you have some states that
>     are not converged at some k-point.
>
>     1) can you confirm that in an older version of QE everything
>     worked perfectly (*which one*?, and in 5.1.2 you have the problems
>     below?
>
>     2) do the outputs in the two cases differ - for the QE runs, and for the
>     wannier runs, when run with *identical* inputs? If so, in what do
>     they differ.
>
>     Let us know re 1) and 2) - thanks a lot,
>
>                              nicola
>
>
>
>     On 15/06/2015 09:40, Seyed Mojtaba Rezaei Sani wrote:
>
>         Dear all
>
>         I am looking forward to receive any kind help.
>
>         On Wed, Jun 10, 2015 at 2:59 PM, Seyed Mojtaba Rezaei Sani
>         <s.m.rezaeisani at gmail.com <mailto:s.m.rezaeisani at gmail.com>
>         <mailto:s.m.rezaeisani at gmail.com
>         <mailto:s.m.rezaeisani at gmail.com>>> wrote:
>
>              Dear Prof. Marzari
>
>              As you suggested I checked input files and they were exactly
>              identical. but the difference in result remains.
>              I tried to make a change in calculations so I increased
>         number of
>              kpoints in non scf and wannier calculations from
>              a mesh of 12*12*1 to 16*16*1. The result was an improvement
>         in band
>              structure. you can find the plot attached. But
>              there are still some inadequacies to the pw band in the
>         region gamma
>              to X.
>              Again I increased the grid to a 24*24*1 mesh which
>         encountered this
>              error:
>
>              Unable to satisfy B1 with any of the first  12 shells
>                Your cell might be very long, or you may have an
>         irregular MP grid
>                Try increasing the parameter search_shells in the win
>         file (default=12)
>
>              Setting the parameter search_shells = 60 solved the problem
>         but now
>              inadequacies are in the region S to Y (the plot is attached).
>              I don't know if there is any parameter that I could change
>         to solve
>              this problem. Please give me any probable hint.
>              Thanks,
>
>              On Wed, Jun 10, 2015 at 2:53 PM, Seyed Mojtaba Rezaei Sani
>              <s.m.rezaeisani at gmail.com <mailto:s.m.rezaeisani at gmail.com>
>         <mailto:s.m.rezaeisani at gmail.com
>         <mailto:s.m.rezaeisani at gmail.com>>> wrote:
>
>                  Dear Prof. Marzari
>
>                  As you suggested I checked input files and they were
>         exactly
>                  identical. but the difference in result remains.
>                  I tried to make a change in calculations so I increased
>         number
>                  of kpoints in non scf and wannier calculations from
>                  a mesh of 12*12*1 to 16*16*1. The result was an
>         improvement in
>                  band structure. you can find the plot attached. But
>                  there are still some inadequacies to the pw band in the
>         region
>                  gamma to X.
>                  Again I increased the grid to a 24*24*1 mesh which
>         encountered
>                  this error:
>
>                  Unable to satisfy B1 with any of the first  12 shells
>                    Your cell might be very long, or you may have an
>         irregular MP grid
>                    Try increasing the parameter search_shells in the win
>         file (default=12)
>
>                  Setting the parameter search_shells = 60 solved the
>         problem but
>                  now inadequacies are in the region S to Y (the plot is
>         attached).
>                  I don't know if there is any parameter that I could
>         change to
>                  solve this problem. Please give me any probable hint.
>                  Thanks,
>
>                  On Thu, May 28, 2015 at 12:39 PM, Nicola Marzari
>                  <nicola.marzari at epfl.ch <mailto:nicola.marzari at epfl.ch>
>         <mailto:nicola.marzari at epfl.ch <mailto:nicola.marzari at epfl.ch>>>
>         wrote:
>
>
>
>                      Well, the obvious thing to do is making sure your
>                      inputs are exactly identical, you re-run the
>         calculations
>                      to make sure the error shows up again, and then you
>         start
>                      doing a diff in the output files of
>         quantum-espresso, and
>                      see where there is a difference.
>
>                                                       nicola
>
>
>
>
>                      On 28/05/2015 09:07, Seyed Mojtaba Rezaei Sani wrote:
>
>                          Dear Wannier90 users,
>
>                          I am trying to calculate wannier functions for
>                          phosphorene using
>                          wannier90. first I tried to plot band structure
>         using both
>                          quantum-espresso and wannier90. Results were in
>         good
>                          agreement. Now I
>                          have upgraded espresso to 5.1.2 version but
>         with the
>                          same inputs the
>                          obtained results are not similar.
>                          All files are attached and here in .win input:
>
>                          num_bands        = 10
>                          num_wann         = 10
>                          num_iter         = 500
>
>                          Begin Unit_Cell_Cart
>                          Bohr
>                                6.282237122     0.000000000     0.0000000000
>                                0.000000000     8.651074073     0.0000000000
>                                0.000000000     0.000000000     26.456165734
>                          End Unit_Cell_Cart
>
>                          Begin Atoms_Frac
>                          P1        0.010000000   0.086656382   0.152592466
>                          P1        0.010000000   0.913343530   0.001000000
>                          P2        0.510000000   0.413343618   0.152592466
>                          P2        0.510000000   0.586656470   0.001000000
>                          End Atoms_Frac
>
>                          Begin Projections
>                          P1:sp3
>                          P2:py
>                          End Projections
>
>                          bands_plot = true
>
>                          begin kpoint_path
>                          G 0.0000 0.0000 0.0000 X 0.5000 0.0000 0.0000
>                          x 0.5000 0.0000 0.0000 S 0.5000 0.5000 0.0000
>                          S 0.5000 0.5000 0.0000 Y 0.0000 0.5000 0.0000
>                          Y 0.0000 0.5000 0.0000 G 0.0000 0.0000 0.0000
>                          end kpoint_path
>
>                          mp_grid = 12 12 1
>
>                          begin kpoints
>                              0.00000000  0.00000000  0.00000000
>                             .
>                             .
>                             .
>                              0.91666667  0.91666667  0.00000000
>                          End Kpoints
>
>                          I would greatly appreciate it if you kindly
>         give me some
>                          hints.
>
>                          Best regards,
>
>                          --
>                          Seyed Mojtaba Rezaei Sani
>
>                          Institute for Research in Fundamental Sciences
>         (IPM)
>                          School of Nano-Science
>                          Shahid Farbin Alley
>                          Shahid Lavasani st
>                          P.O. Box 19395-5531
>                          Tehran, Iran
>                          Tel: +98 21 2310  (3069)
>
>
>                          _______________________________________________
>                          Wannier mailing list
>         Wannier at quantum-espresso.org <mailto:Wannier at quantum-espresso.org>
>                          <mailto:Wannier at quantum-espresso.org
>         <mailto:Wannier at quantum-espresso.org>>
>
>         http://mailman.qe-forge.org/cgi-bin/mailman/listinfo/wannier
>
>
>                      --
>
>
>         ----------------------------------------------------------------------
>                      Prof Nicola Marzari, Chair of Theory and Simulation of
>                      Materials, EPFL
>                      Director, National Centre for Competence in
>         Research NCCR
>                      MARVEL, EPFL
>
>
>
>
>                  --
>                  Seyed Mojtaba Rezaei Sani
>
>                  Institute for Research in Fundamental Sciences (IPM)
>                  School of Nano-Science
>                  Shahid Farbin Alley
>                  Shahid Lavasani st
>                  P.O. Box 19395-5531
>                  Tehran, Iran
>                  Tel: +98 21 2310  (3069)
>
>
>
>
>              --
>              Seyed Mojtaba Rezaei Sani
>
>              Institute for Research in Fundamental Sciences (IPM)
>              School of Nano-Science
>              Shahid Farbin Alley
>              Shahid Lavasani st
>              P.O. Box 19395-5531
>              Tehran, Iran
>              Tel: +98 21 2310  (3069)
>
>
>
>
>         --
>         Seyed Mojtaba Rezaei Sani
>
>         Institute for Research in Fundamental Sciences (IPM)
>         School of Nano-Science
>         Shahid Farbin Alley
>         Shahid Lavasani st
>         P.O. Box 19395-5531
>         Tehran, Iran
>         Tel: +98 21 2310  (3069)
>
>
>     --
>
>     ----------------------------------------------------------------------
>     Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
>     Director, National Centre for Competence in Research NCCR MARVEL, EPFL
>
>
>
>
> --
> Seyed Mojtaba Rezaei Sani
>
> Institute for Research in Fundamental Sciences (IPM)
> School of Nano-Science
> Shahid Farbin Alley
> Shahid Lavasani st
> P.O. Box 19395-5531
> Tehran, Iran
> Tel: +98 21 2310  (3069)

-- 

----------------------------------------------------------------------
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
Director, National Centre for Competence in Research NCCR MARVEL, EPFL



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