[Q-e-developers] dv_of_drho optional arguments

[Paolo Giannozzi]

It is a known problem that was raised in the pw_forum mailing list. I have
no strong opinions about this (well, I have one on some compilers, but this
is of no help) but I tend to agree that the best (or the only) solution is
to put the routine dv_of_drho into a module.

Paolo

On Wed, May 11, 2016 at 5:29 PM, Timrov Iurii <iurii.timrov at epfl.ch> wrote:

> Dear Lorenzo,
>
> You are totally right! In fact, one of the QE users also noticed such a
> problem with the routine dv_of_drho when using xlf.
>
> It is my mistake to introduce such a bug in dv_of_drho. Sorry about that!
>
> In my opinion, the first option which you suggest is better. Personally I
> do not like the second option, because in several places of PHonon and in
> TDDFPT the routine dv_of_drho is called without the need to pass the
> response core charge density "drhoc". So, in the case of the second option,
> one would need to pass a zero array drhoc=(0.0d0, 0.0d0) to dv_of_drho,
> which has no sense and moreover it consumes some memory without any need
> (add_nlcc=.false. in that case, so such a zero array will not be used).
>
> Best regards,
> Iurii
>
>
> --
> Dr. Iurii Timrov
> Postdoctoral Researcher
> Swiss Federal Institute of Technology Lausanne (EPFL)
> Laboratory of Theory and Simulation of Materials (THEOS)
> CH-1015 Lausanne, Switzerland
>
>
> ________________________________________
> From: q-e-developers-bounces at qe-forge.org <
> q-e-developers-bounces at qe-forge.org> on behalf of Lorenzo Paulatto <
> lorenzo.paulatto at impmc.upmc.fr>
> Sent: Wednesday, May 11, 2016 5:00 PM
> To: discussion developers
> Subject: [Q-e-developers] dv_of_drho optional arguments
>
> Hello,
> I have noticed that the subroutine dv_of_drho in LR_Modules has an optional
> argument. However, this subroutine does not have an explicit interface
> (i.e.
> it is not in a module), which can cause problems. It does indeed cause
> problems with xlf.
>
> There are two possible solutions:
> 1. put the subroutine in a module
> 2. make the argument non optional
>
> As the subroutine is used in several codes (phonon, tddft) I want to ask
> your
> opinion before proceeding
>
> cheers
>
> --
> Dr. Lorenzo Paulatto
> IdR @ IMPMC -- CNRS & Université Paris 6
> +33 (0)1 44 275 084 / skype: paulatz
> http://www.impmc.upmc.fr/~paulatto/
> 23-24/4é16 Boîte courrier 115,
> 4 place Jussieu 75252 Paris Cédex 05
>
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-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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