[x,Vnl] slows the Dipoles computation

Deals with issues related to computation of optical spectra in reciprocal space: RPA, TDDFT, local field effects.

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Stephan
Posts: 62
Joined: Thu Jan 15, 2015 12:48 pm

[x,Vnl] slows the Dipoles computation

Post by Stephan » Mon Oct 12, 2015 4:08 pm

Hi everybody,

A short question: I often read this message in log and report files.

[x,Vnl] slows the Dipoles computation. To neglect it rename the ns.kb_pp file

How much are the computation slowed and why?

Thanks and regards

Stephan
Stephan Ludwig
1. phyical institute
University Stuttgart
Germany

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Daniele Varsano
Posts: 4198
Joined: Tue Mar 17, 2009 2:23 pm
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Re: [x,Vnl] slows the Dipoles computation

Post by Daniele Varsano » Mon Oct 12, 2015 4:15 pm

Dear Stephan,
how much it depends on how much dipole matrix elements needs to be computed (essentially the bands included in the calculations).
Why, just because they need to be evaluated.
How much they are important, it is system dependent.
Anyway if you do not rename/delete the ns.kb_pp files, the commutator is included by defalut.

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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