[QE-users] Probable bug in additional_kpoints.f90 subroutine

[Prasenjit Ghosh]

On Tue, 15 Feb 2022 at 18:40, Lorenzo Paulatto <
lorenzo.paulatto at sorbonne-universite.fr> wrote:

> Thank you Prasenjit, I tested it and it seems correct. I also fixeda
> couple of bugs in plotbands.
>
> Do you want to do a pull request yourself for the file ? (In that case
> I'ld ask you to remove the debug lines) or should I take care to do it?
>
>
Thanks Lorenzo. I think the simplest thing will be that you please go ahead
and take care of it.

With regards,
Prasenjit



> thank you again
>
> Dr. Lorenzo Paulatto
> IdR @ IMPMC - CNRS UMR 7590 & Sorbonne Université
> phone: +33 (0)1 442 79822 / skype: paulatz
> http://www.impmc.upmc.fr/~paulatto/ - https://anharmonic.github.io/
> 23-24/423 B115, 4 place Jussieu 75252 Paris CX 05
> On Feb 15 2022, at 7:29 am, Prasenjit Ghosh <prasenjit.jnc at gmail.com>
> wrote:
>
> Dear Lorenzo and others,
>
> I think there is a bug in the above subroutine when either nqx1, nqx2 and
> nqx3, or all of them are greater than 1. The example does not work with the
> original version of the code because a lot of k-points with coordinates
> (0,0,0 are generated as shown below:
>
>         k(    1) = (  -0.2500000   0.2500000   0.2500000), wk =   0.5000000
>         k(    2) = (   0.2500000  -0.2500000   0.7500000), wk =   1.5000000
>         k(    3) = (   0.0000000   0.0000000   0.0000000), wk =   0.0000000
>         k(    4) = (   0.0000000   0.0000000   0.0000000), wk =   0.0000000
>         k(    5) = (   0.0000000   0.0000000   0.0000000), wk =   0.0000000
>         k(    6) = (   0.0000000   0.0000000   0.0000000), wk =   0.0000000
>         k(    7) = (   0.0000000   0.0000000   0.0000000), wk =   0.0000000
>         k(    8) = (   0.0000000   0.0000000   0.0000000), wk =   0.0000000
>         k(    9) = (   0.5000000   0.5000000   0.5000000), wk =   0.0000000
>
> In the above list, k-points #3 to #7 are all (0, 0,0). Because of this,
> when running the bands.x code, it complains and stops.
>
> I was working with QE-6.8. The same problem I think persists also in 7.0.
>
> In line 89 of the subroutine, the value of the counter 'iq' seems to be
> wrongly initialized. With this the array elements are wrongly assigned in
> xk(:,ik). The correct one should be:
>
> iq=nkstot_old
>
> Further the array elements of 'wk', corresponding to the additional
> k-points also need to be set to zero. This can be done right after line 98
> by adding the following line:
> wk(iq)=0.0d0
>
> The modified subroutine is attached.
>
> With regards,
> Prasenjit
>
>
> With regards,
> Prasenjit
> --
> PRASENJIT GHOSH,
> IISER Pune,
> Dr. Homi Bhabha Road, Pashan
> Pune, Maharashtra 411008, India
>
> Phone: +91 (20) 2590 8203
> Fax: +91 (20) 2589 9790
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-- 
PRASENJIT GHOSH,
IISER Pune,
Dr. Homi Bhabha Road, Pashan
Pune, Maharashtra 411008, India

Phone: +91 (20) 2590 8203
Fax: +91 (20) 2589 9790
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