Response Block Size

Concerns any physical issues arising during the setup step (-i option). This includes problems with symmetries, k/q-point sets, and so on. For technical problems (running in parallel, etc), refer to the Technical forum.

Moderator: Daniele Varsano

Response Block Size

Postby adipopescu2000 » Tue May 10, 2016 10:02 pm

Hello,
I am a new Yambo user, and I am trying to run a GoWo quasiparticles correction. What is the meaning of the NGsBlkXp variable, response block size?
Thanks,
Adrian Popescu
Postdoctoral Researcher
North Carolina Central University
adipopescu2000
 
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Re: Response Block Size

Postby Daniele Varsano » Tue May 10, 2016 10:49 pm

Dear Adrian,
NGsBlkXp define the dimension of the inverse dielectric matrix \eps_GG' you need in the plasmon pole approximation to build up the screened Coulomb potential W_GG'.
You can have a look here or more in details Eqs.5 and the following equations in the yambo paper.
A. Marini et al. Comp. Phys. Comm. 180, 1392 (2009)

Best,

Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/
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Re: Response Block Size

Postby adipopescu2000 » Tue May 10, 2016 11:31 pm

Hi Daniele,

Thank you for your reply. So if I correctly understand, the response block size is bounded by the total number of bands of the system?

Best,
Adrian
Adrian Popescu
Postdoctoral Researcher
North Carolina Central University
adipopescu2000
 
Posts: 2
Joined: Fri Mar 04, 2016 6:49 pm

Re: Response Block Size

Postby Daniele Varsano » Tue May 10, 2016 11:39 pm

Dear Adrian,
no, the blocks are in G-space and are not related with the number of bands.
I invite you to follow the equation and convince yourself.
You have a sum over states (bands) in order to build the X^0 response function, but the G components are only limited to the plane wave cutoff.

Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/
User avatar
Daniele Varsano
 
Posts: 2022
Joined: Tue Mar 17, 2009 2:23 pm


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