[Pw_forum] Question about GGA+U in DFPT

[Axel Kohlmeyer]

On Fri, Apr 11, 2014 at 8:24 AM, Suza W <suza.rri at gmail.com> wrote:
> Dear Jiawei,
>
> Unfortunately, DFPT+U is not in public domain since 2009.

please be *very* careful with statements like this. "public domain" is
something very different from "open source", which in turn is
different from the "GNU public license" and which in turn is different
from "published".

there also is the difference between what kind of data (including
source code) the scientific community requires to make published work
reproducible and what you are obliged to.

also, there is often a confusion about what copyright and a license means.
it is very easy to misstate something and to give people a wrong impression.

"public domain" means that somebody 'abandons' a piece of text (or
code) and lets anybody do with it whatever they want.

code under the GPL is *not* that. it is still copyrighted material and
the author of a piece of code "owns" it. but the GPL allows anybody to
take GPL'd code and use it (personally) in whatever way they want to
use it. the GPL only becomes important if somebody _redistributes_ the
software (be it as source code or as executable and it doesn't
matter(!) whether it is for a fee or not). at that point, it is
required to always include modifications and extensions as source code
and not limit the use in any way beyond the limitations imposed by the
GPL. the GPL itself does not require publication of any extensions or
modifications *unless* those modifications are redistributed.

axel.

> You may try ABINIT for DFPT+U, if you like.
>
> Best,
> Suza
>
>
>
> On Fri, Apr 11, 2014 at 10:41 AM, Andrea Floris <an.floris at gmail.com> wrote:
>>
>> Dear Jiawei,
>> The DFPT+U implementation is not yet public.  I have recently ported the
>> code in the last version,  I am optimizing a couple of routines to calculate
>> the second derivatives of the occupation matrices,  which is a rather heavy
>> calculation when using ultrasoft pseudos. In a couple of months it should be
>> available.
>> Best,
>> Andrea
>>
>> >
>> > ---------- Forwarded message ----------
>> > From: Jiawei Zhou (周嘉炜) <zhoujw20 at gmail.com>
>> > Date: Mon, Apr 7, 2014 at 4:54 PM
>> > Subject: [Pw_forum] Question about GGA+U in DFPT
>> > To: pw_forum <pw_forum at pwscf.org>
>> > Cc: Jenny Wang <jy_wang at mit.edu>, 杨远 <yangyuan1985 at gmail.com>
>> >
>> >
>> > Dear all,
>> >
>> > I was planning to use ph.x to calculate the phonon dispersion for some
>> > transition metal oxide within GGA+U, following the work in a paper (A.
>> > Floris et al., Vibrational properties of MnO and NiO from DFT + U-based
>> > density functional perturbation theory, PRB, 84 (2011)), which has developed
>> > GGA+U for DFPT and implemented for two materials MnO and NiO, and also
>> > mentioned that the extension is implemented in the phonon package. However I
>> > found the manual for ph.x says:
>> >
>> > "The main code ph.x can be used whenever PWscf can be used, with the
>> > exceptions of
>> > DFT+U, nonlocal VdW and hybrid functionals"
>> >
>> > So I am confused about whether or not the current phonon package can do
>> > a GGA+U calculation? If not, is LDA+U available using ph.x for the phonon
>> > dispersion? Or is that part still under development? Thanks so much for your
>> > help!
>> >
>> > Best,
>> >
>> > Jiawei
>> > Massachusetts Institute of Technology
>> >
>> >
>> >
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>>
>>
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-- 
Dr. Axel Kohlmeyer  akohlmey at gmail.com  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.