LANCZOSTHR: Difference between revisions

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(Created page with "{TAGDEF|LANCZOSTHR|[real]}} {{DEF|LANCZOSTHR| <math>10^{-3}</math> | }} Description: {{TAG|LANCZOSTHR}} is used by the BSE Lanczos algorithm to stop the iterative procedure, once the dielectric function has reached numerical convergence. The difference between the dielectric function at two consecutive iterations, <math>i</math> and <math>i+1</math> is computed as root-mean-square over the frequency grid sampling ::<math> \mathrm{RMS}[\epsilon] = \sqrt{\sum_{j=1}^N\le...")
 
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{TAGDEF|LANCZOSTHR|[real]}}
{{NB|deprecated|This feature is deprecated and will be removed in a future release. Please use {{TAG|BSEPREC}} instead.}}
{{DEF|LANCZOSTHR| <math>10^{-3}</math> | }}
 
{{TAGDEF|LANCZOSTHR|[real]|<math>10^{-3}</math>}}


Description: {{TAG|LANCZOSTHR}} is used by the BSE Lanczos algorithm to stop the iterative procedure, once the dielectric function has reached numerical convergence.
Description: {{TAG|LANCZOSTHR}} is used by the BSE Lanczos algorithm to stop the iterative procedure, once the dielectric function has reached numerical convergence.


The difference between the dielectric function at two consecutive iterations, <math>i</math> and <math>i+1</math> is computed as root-mean-square over the frequency grid sampling
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The difference between the dielectric function at two consecutive iterations, <math>i</math> and <math>i+1</math>, is computed as root-mean-square over the frequency grid


::<math>
::<math>
\mathrm{RMS}[\epsilon] = \sqrt{\sum_{j=1}^N\left[\epsilon_{i}(\omega_j)-\epsilon_{i+1}(\omega_j)\right]^2}
\mathrm{RMS}[\epsilon] = \sqrt{\sum_{j=1}^N\frac{1}{N}\left[\epsilon_{i}(\omega_j)-\epsilon_{i+1}(\omega_j)\right]^2}
</math>
</math>


and once <math>\mathrm{RMS}[\epsilon]<=</math>LANCZOSTHR the iterative procedure stops.  
and once <math>\mathrm{RMS}[\epsilon]<=</math>{{TAG|LANCZOSTHR}} the iterative algorithm stops.  
 
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== Related tag and articles ==
== Related tag and articles ==
{{TAG|IBSE}},
{{TAG|BSE}},
{{TAG|BSEPREC}},
{{TAG|NBANDSV}},
{{TAG|NBANDSO}},
{{TAG|CSHIFT}},
{{TAG|OMEGAMAX}},
[[BSE calculations]],
[[BSE calculations]],
[[Bethe-Salpeter equations]]
[[Bethe-Salpeter equations]]
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[[Category:INCAR tag]][[Category:Bethe-Salpeter equations]][[Category:Many-body perturbation theory]]

Latest revision as of 12:42, 16 October 2025

Deprecated: This feature is deprecated and will be removed in a future release. Please use BSEPREC instead.

LANCZOSTHR = [real]
Default: LANCZOSTHR = [math]\displaystyle{ 10^{-3} }[/math] 

Description: LANCZOSTHR is used by the BSE Lanczos algorithm to stop the iterative procedure, once the dielectric function has reached numerical convergence.


The difference between the dielectric function at two consecutive iterations, [math]\displaystyle{ i }[/math] and [math]\displaystyle{ i+1 }[/math], is computed as root-mean-square over the frequency grid

[math]\displaystyle{ \mathrm{RMS}[\epsilon] = \sqrt{\sum_{j=1}^N\frac{1}{N}\left[\epsilon_{i}(\omega_j)-\epsilon_{i+1}(\omega_j)\right]^2} }[/math]

and once [math]\displaystyle{ \mathrm{RMS}[\epsilon]\lt = }[/math]LANCZOSTHR the iterative algorithm stops.

Related tag and articles

BSE, BSE calculations, Bethe-Salpeter equations