[Pw_forum] (no subject)

[Lorenzo Paulatto]

On mardi 4 avril 2017 12:06:13 CEST VineetKumar Pandey wrote:
> vineetkumar.pandey at students.iiserpune.ac.in> wrote:
> > dear users , I am using third order software to generate 3rd order force
> > constant . where I am getting an error "ValueError: operands could not be
> > broadcast together with shapes (3,27) (3,189) (3,27) " . can anyone help

Dear Vineet,
the thirorder.py is a topic a bit outside of the domain of this forum, it has 
its own page on bitbucket <https://bitbucket.org/sousaw/thirdorder> which I 
guess has some kind of issue tracker, although I cannot find it.

That said, the cause of the error is that thirdorder does not read correctly 
the output files produced with the verbosity="high" flag. I'm attaching a fixed 
version which works in this case.

A couple more notes:

1. be absolutely sure that you feed the output files in the correct order 
(which is NOT necessarily the one returned by ls), or the results will be 
wrong. I recommend making a list of the output files in a text file, check that 
the order is correct, and the do something like
cat LIST.txt | thirdorder_espresso.py reap ....

2. I have developed, a code for computing the third derivative using 
perturbation theory on top of phonon, it is much more efficient than finite 
differences although it is limited to norm-conserving pseudo-potential. 
It also includes a set of codes for doing phonon lifetimes and thermal 
transport calculations, it can also import the file of force constants produced 
by thirdorder.py
You can check it here: <https://sourceforge.net/projects/d3q/>, or simply do a 
make d3q
From QE 6.1 (there are quite a few bugs in the version for QE 6.0 and 
previous, so I strongly recommend you get the very last one)

HTH









-- 
Dr. Lorenzo Paulatto 
IdR @ IMPMC -- CNRS & Université Paris 6
phone: +33 (0)1 442 79822 / skype: paulatz
www:   http://www-int.impmc.upmc.fr/~paulatto/
mail:  23-24/423 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05
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