[Pw_forum] questions about computing the third order coupling tensor implemented by d3.x code

[Tian Lan]

Thank you, Dr. Paulatto. Yes, I paid attention to your note, but the
sentence " the second one [of the matrix elements] has the real part in a
line and the imaginary in the next" confused me. My observation is like:

xx_Re, xx_Im, xy_Re
xy_Im, xz_Re, xz_Im
yx_Re, yx_Im, yy_Re
....
So for a Cartisian pair, say xy, the real and imaginary parts neighbored,
and not follow the matrix indices order, but just simply turn to a new row
when the column hits 3. I don't know exactly what you wrote the second one
of the matrix element refer to. I hope it means the same.

And to every experienced d3.x users:

If I want to calculate the phonon lifetime, one X point as in example14 is
obviously not enough, I need a q point sampling. In this case, I know ph.x
can do the job with the commands, e.g.

ldisp= true
q1=2
q2=2
q3=2

But there is no hint about how to implement the same thing with d3.x
followed the phonon calculation, I tried to erase the 0 0 1 in the end of
d3 script for X point, but the code does not take the mutiple dyn's from
phonon outcome and just crashes.

I guess d3 still needs some input for q points, but seemingly there is
no way to input more than one q point similar to ph.x. It can only accept
one q point at the end of the script. I hope I am wrong, otherwise, if
I have 100 q points, then I need to repeat for each point 100 times.

Best,
Tian

On Thu, Dec 20, 2012 at 12:41 AM, Lorenzo Paulatto <
lorenzo.paulatto at impmc.upmc.fr> wrote:

> On 20 December 2012 06:21, Tian Lan <tianlan at caltech.edu> wrote:
>
>> It looks a little strange though written in this way, please confirm my
>> conclusion.
>>
>
> As I wrote in February:
> > Yes, the second one [of the matrix elements] has the real part in a line
> and the imaginary in the next...
>
>
>>  I am using a 4.2.1 version.
>>
>
> There was a bug with pools up to a certain version, use the latest one
> (and apply this fix: <
> http://qe-forge.org/gf/project/q-e/scmsvn/?action=browse&path=%2Ftrunk%2Fespresso%2FPHonon%2FPH%2Fsgam_ph.f90&r1=9630&r2=9724
> >)
>
> bests
>
>
>
> --
> Dr. Lorenzo Paulatto
> IdR @ IMPMC -- CNRS & Université Paris 6
> phone: +33 (0)1 44275 084 / skype: paulatz
> www:   http://www-int.impmc.upmc.fr/~paulatto/
> mail:  23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
>



-- 
Lan, Tian
Ph.D. Candidate, Department of Applied Physics and Materials Science
California Institute of Technology,
Caltech M/C 138-78, Pasadena, CA, 91125
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20121220/9d2ead30/attachment.html>