[Pw_forum] PW.x homogeneous electric field berry phase calculation in trigonal cell

[Louis Fry-Bouriaux]

Hi Lorenzo,


   Thanks for clarifying!


   Yes that was quite silly of me to have nosym=.false., but yes it has no effect I still get the 'wrong g' error.


   I will now manually specify the k-points and relay what happens later..


   I am very interested in solving the bottleneck issue as I wish to perform a much more intensive calculation using a large amorphous cell, and later move on to using ESM, so I am debugging as best as I can to first understand the code and what exactly causes the bottleneck. Are you able to share any additional technical information on this issue?


Thank you so much for you help and assistance,

Louis

________________________________
From: pw_forum-bounces at pwscf.org <pw_forum-bounces at pwscf.org> on behalf of Lorenzo Paulatto <lorenzo.paulatto at impmc.upmc.fr>
Sent: 08 February 2017 19:57:19
To: PWSCF Forum
Subject: Re: [Pw_forum] PW.x homogeneous electric field berry phase calculation in trigonal cell

On Wednesday, February 8, 2017 5:46:25 PM CET Louis Fry-Bouriaux wrote:
>     In your last email you mentioned the field 'pdir', I have not been able
> to find this in the documentation, is this what you meant?

It is the internal name of a variable in the subroutine that computes the
macroscopic polarisation, but I think it is always gdir in the end.

> as this is where the error is when I use other than gdir=3 (I added ln 364
> to identify what fails exactly)

I never did this myself, but from the code expects strings of k-points, one
after each other. Each string is formed by nppstr k-points, aligned in the
direction gdir; there can be as many string as you want, in principle to form
a grid in the two directions orthogonal to gdir.

Maybe in the case gdir=3 these string are formed "spontaneously" when using k-
points automatic, but it does not work in the other cases. The polarisation
(berry=.true.) and the electric field (lefield=.true.) codes are very similar,
but not identical, in theory the second is more general, I'm not too familiar
with either.

I've noticed that you set nosym=.false., I'm quite sure that that swith is
overridden with lefield, but to be sure, could you try to sisable it?




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