LSPECTRAL - Revision history

Huebsch at 10:11, 19 July 2022

2022-07-19T10:11:52Z

← Older revision		Revision as of 10:11, 19 July 2022
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	----		----

	If {{TAG\|LSPECTRAL}} = .TRUE. is set, the imaginary part of the independent particle polarizability <math>\chi_{\mathbf{q}}^0 (\mathbf{G}, \mathbf{G}', \omega)</math> is calculated first, and afterwards the full independent particle polarizability is determined using a Kramers-Kronig (or Hilbert) transform. This reduces the computational ~~work load~~ by almost a factor {{TAG\|NOMEGA}}/2. The downside of the coin is that the response function must be kept in memory for all considered frequencies, which can cause excessive memory requirements. VASP therefore distributes the dielectric functions among the available compute nodes.		If {{TAG\|LSPECTRAL}} = .TRUE. is set, the imaginary part of the independent particle polarizability <math>\chi_{\mathbf{q}}^0 (\mathbf{G}, \mathbf{G}', \omega)</math> is calculated first, and afterwards the full independent particle polarizability is determined using a Kramers-Kronig (or Hilbert) transform. This reduces the computational workload by almost a factor {{TAG\|NOMEGA}}/2. The downside of the coin is that the response function must be kept in memory for all considered frequencies, which can cause excessive memory requirements. VASP, therefore, distributes the dielectric functions among the available compute nodes.

	A similar trick is used when the QP-shifts are calculated. In general it is strongly recommended to set {{TAG\|LSPECTRAL}} = .TRUE., except if memory requirements are too excessive.		A similar trick is used when the QP-shifts are calculated. In general it is strongly recommended to set {{TAG\|LSPECTRAL}} = .TRUE., except if memory requirements are too excessive.
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	----		----

	[[Category:INCAR tag]][[Category:Many-~~Body Perturbation Theory~~]] [[Category:GW]]		[[Category:INCAR tag]][[Category:Many-body perturbation theory]][[Category:GW]]

Karsai: /* Related Tags and Sections */

2022-04-08T14:42:36Z

Related Tags and Sections

← Older revision		Revision as of 14:42, 8 April 2022
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	A similar trick is used when the QP-shifts are calculated. In general it is strongly recommended to set {{TAG\|LSPECTRAL}} = .TRUE., except if memory requirements are too excessive.		A similar trick is used when the QP-shifts are calculated. In general it is strongly recommended to set {{TAG\|LSPECTRAL}} = .TRUE., except if memory requirements are too excessive.

	== Related ~~Tags~~ and ~~Sections~~ ==		== Related tags and articles ==
	{{TAG\|NOMEGA}},		{{TAG\|NOMEGA}},
	{{TAG\|LSPECTRALGW}}		{{TAG\|LSPECTRALGW}}
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	----		----

	[[Category:INCAR]][[Category:Many-Body Perturbation Theory]] [[Category:GW]]		[[Category:INCAR tag]][[Category:Many-Body Perturbation Theory]] [[Category:GW]]

Karsai at 14:58, 11 March 2019

2019-03-11T14:58:58Z

← Older revision		Revision as of 14:58, 11 March 2019
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	{{sc\|LSPECTRAL\|Examples\|Examples that use this tag}}		{{sc\|LSPECTRAL\|Examples\|Examples that use this tag}}
	----		----
	~~[[The_VASP_Manual\|Contents]]~~

	[[Category:INCAR]] [[Category:GW]]		[[Category:INCAR]][[Category:Many-Body Perturbation Theory]] [[Category:GW]]

Karsai at 10:33, 20 March 2017

2017-03-20T10:33:02Z

← Older revision		Revision as of 10:33, 20 March 2017
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	{{TAG\|LSPECTRALGW}}		{{TAG\|LSPECTRALGW}}

	~~== Example Calculations using this Tag ==~~		{{sc\|LSPECTRAL\|Examples\|Examples that use this tag}}
	{{~~TAG~~\|~~bandgap of Si in GW}}, {{TAG~~\|~~bandstructure of Si in GW (VASP2WANNIER90)}}, {{TAG~~\|~~dielectric properties of Si~~}}
	----		----
	[[The_VASP_Manual\|Contents]]		[[The_VASP_Manual\|Contents]]

	[[Category:INCAR]] [[Category:GW]]		[[Category:INCAR]] [[Category:GW]]

Kresse: /* Related Tags and Sections */

2017-03-13T17:55:19Z

Related Tags and Sections

← Older revision		Revision as of 17:55, 13 March 2017
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	== Related Tags and Sections ==		== Related Tags and Sections ==
	{{TAG\|NOMEGA}}		{{TAG\|NOMEGA}},

	{{TAG\|LSPECTRALGW}}		{{TAG\|LSPECTRALGW}}

Kresse: /* Related Tags and Sections */

2017-03-13T17:55:07Z

Related Tags and Sections

← Older revision		Revision as of 17:55, 13 March 2017
Line 11:		Line 11:
	== Related Tags and Sections ==		== Related Tags and Sections ==
	{{TAG\|NOMEGA}}		{{TAG\|NOMEGA}}

	{{TAG\|LSPECTRALGW}}		{{TAG\|LSPECTRALGW}}

Kresse: /* Related Tags and Sections */

2017-03-13T17:54:57Z

Related Tags and Sections

← Older revision		Revision as of 17:54, 13 March 2017
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	== Related Tags and Sections ==		== Related Tags and Sections ==
	{{TAG\|NOMEGA}}		{{TAG\|NOMEGA}}
			{{TAG\|LSPECTRALGW}}

	== Example Calculations using this Tag ==		== Example Calculations using this Tag ==

Karsai at 15:26, 15 February 2017

2017-02-15T15:26:56Z

← Older revision		Revision as of 15:26, 15 February 2017
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	== Related Tags and Sections ==		== Related Tags and Sections ==
	{{TAG\|NOMEGA}}		{{TAG\|NOMEGA}}

			== Example Calculations using this Tag ==
			{{TAG\|bandgap of Si in GW}}, {{TAG\|bandstructure of Si in GW (VASP2WANNIER90)}}, {{TAG\|dielectric properties of Si}}
	----		----
	[[The_VASP_Manual\|Contents]]		[[The_VASP_Manual\|Contents]]

	[[Category:INCAR]] [[Category:GW]]		[[Category:INCAR]] [[Category:GW]]

Mmars at 14:47, 28 February 2011

2011-02-28T14:47:02Z

← Older revision		Revision as of 14:47, 28 February 2011
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	[[The_VASP_Manual\|Contents]]		[[The_VASP_Manual\|Contents]]

	[[Category:INCAR]] [[Category:GW ~~calculations~~]]		[[Category:INCAR]] [[Category:GW]]

Kerstin: Created page with '{{TAGDEF|LSPECTRAL|.FALSE. {{!}} .TRUE.}} {{DEF|LSPECTRAL|.TRUE.|if {{TAG|NOMEGA}}>2}} Description: {{TAG|LSPECTRAL}} specifies to use the spectral method. ---- If {{TAG|LSPECT…'

2011-02-23T10:35:21Z

Created page with '{{TAGDEF|LSPECTRAL|.FALSE. {{!}} .TRUE.}} {{DEF|LSPECTRAL|.TRUE.|if {{TAG|NOMEGA}}>2}} Description: {{TAG|LSPECTRAL}} specifies to use the spectral method. ---- If {{TAG|LSPECT…'

New page

{{TAGDEF|LSPECTRAL|.FALSE. {{!}} .TRUE.}}
{{DEF|LSPECTRAL|.TRUE.|if {{TAG|NOMEGA}}>2}}

Description: {{TAG|LSPECTRAL}} specifies to use the spectral method.
----

If {{TAG|LSPECTRAL}} = .TRUE. is set, the imaginary part of the independent particle polarizability <math>\chi_{\mathbf{q}}^0 (\mathbf{G}, \mathbf{G}', \omega)</math> is calculated first, and afterwards the full independent particle polarizability is determined using a Kramers-Kronig (or Hilbert) transform. This reduces the computational work load by almost a factor {{TAG|NOMEGA}}/2. The downside of the coin is that the response function must be kept in memory for all considered frequencies, which can cause excessive memory requirements. VASP therefore distributes the dielectric functions among the available compute nodes.

A similar trick is used when the QP-shifts are calculated. In general it is strongly recommended to set {{TAG|LSPECTRAL}} = .TRUE., except if memory requirements are too excessive.

== Related Tags and Sections ==
{{TAG|NOMEGA}}
----
[[The_VASP_Manual|Contents]]

[[Category:INCAR]] [[Category:GW calculations]]