BSE solvers overview - Revision history

Nicolaspallanzani: /* Navigate */

2025-05-21T14:12:18Z

Navigate

← Older revision		Revision as of 14:12, 21 May 2025
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	==Navigate==		==Navigate==
			* Back to [[Modena 2025]]
	* Back to [[Rome 2023#Tutorials]]		* Back to [[Rome 2023#Tutorials]]
	* Back to [[BSE hBN Yambo Virtual 2021 version\|BSE tutorial sections]]		* Back to [[BSE hBN Yambo Virtual 2021 version\|BSE tutorial sections]]

Fulvio: /* Navigate */

2023-05-19T16:50:45Z

Navigate

← Older revision		Revision as of 16:50, 19 May 2023
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	==Navigate==		==Navigate==
			* Back to [[Rome 2023#Tutorials]]
	* Back to [[BSE hBN Yambo Virtual 2021 version\|BSE tutorial sections]]		* Back to [[BSE hBN Yambo Virtual 2021 version\|BSE tutorial sections]]
	* Back to [[ICTP 2022]]		* Back to [[ICTP 2022]]

Fulvio: /* Full diagonalization solver */

2023-05-19T16:47:23Z

Full diagonalization solver

← Older revision		Revision as of 16:47, 19 May 2023
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	Unfortunately, the computational cost of full diagonalization is cubic in the number of electron-hole pairs so this solver can be used for small system only (few light atoms per unit cell).		Unfortunately, the computational cost of full diagonalization is cubic in the number of electron-hole pairs so this solver can be used for small system only (few light atoms per unit cell).

	You should~~'ve~~ already ~~carry~~ out the '''[[Bethe-Salpeter solver: diagonalization]]'''. If you wish, you can run again this part and then '''return to this tutorial'''		You should have already carried out the '''[[Bethe-Salpeter solver: diagonalization]]'''. If you wish, you can run again this part and then '''return to this tutorial'''

	===Lanczos-Haydock solver===		===Lanczos-Haydock solver===

Davide: /* Navigate */

2022-04-06T10:15:54Z

Navigate

← Older revision		Revision as of 10:15, 6 April 2022
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	==Navigate==		==Navigate==
	* Back to [[BSE hBN Yambo Virtual 2021 version\|BSE tutorial sections]]		* Back to [[BSE hBN Yambo Virtual 2021 version\|BSE tutorial sections]]
			* Back to [[ICTP 2022]]
	* Back to [[CECAM VIRTUAL 2021]]		* Back to [[CECAM VIRTUAL 2021]]
	* [[Modules\|Back to technical modules menu]]		* [[Modules\|Back to technical modules menu]]

Attacc: /* Lanczos-Haydock solver */

2022-04-05T07:54:06Z

Lanczos-Haydock solver

← Older revision		Revision as of 07:54, 5 April 2022
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	===Lanczos-Haydock solver===		===Lanczos-Haydock solver===
	Subspace iterative [https://en.wikipedia.org/wiki/Lanczos_algorithm/\| Lanczos algorithm] which by-pass diagonalization with the Haydock approach<ref>R. Haydock, in		Subspace iterative [https://en.wikipedia.org/wiki/Lanczos_algorithm \| Lanczos algorithm] which by-pass diagonalization with the Haydock approach<ref>R. Haydock, in
	''Solid State Phys.'', '''35''' 215 (1980) edited by H. Ehrenfest, F. Seitz, and D. Turnbull, Academic Press</ref>.		''Solid State Phys.'', '''35''' 215 (1980) edited by H. Ehrenfest, F. Seitz, and D. Turnbull, Academic Press</ref>.

	This solver outputs the macroscopic dielectric function over a range of energies chosen by the user. It can be applied to medium-large systems as it is substantially cheaper than the full diagonalization (quadratic with the number of electron-hole pairs). However, this approach ''does not provide'' the individual exciton energies and composition in terms of electron-hole pairs.		This solver outputs the macroscopic dielectric function over a range of energies chosen by the user. It can be applied to medium-large systems as it is substantially cheaper than the full diagonalization (quadratic with the number of electron-hole pairs). However, this approach ''does not provide'' the individual exciton energies and composition in terms of electron-hole pairs.

	Follow the link to '''[[Bethe-Salpeter solver: Lanczos-Haydock]]''' then '''return to this tutorial'''		Follow the link to '''[[Bethe-Salpeter solver: Lanczos-Haydock]]''' then '''return to this tutorial'''

	===SLEPc solver ===		===SLEPc solver ===

Myrta at 08:32, 13 April 2021

2021-04-13T08:32:47Z

← Older revision		Revision as of 08:32, 13 April 2021
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	'''Optional:'''		'''Optional:'''
	Advanced users can recompile Yambo with the ''--enable-slepc-linalg'' option if they hadn't done so.		Advanced users can recompile Yambo with the ''--enable-slepc-linalg'' option if they hadn't done so.
	If/Once you have a Yambo version compiled with the SLEPc, or you have the Virtual Machine or the Docker (with the yambo-gcc_openmp_petsc [[container ~~\| CECAM_VIRTUAL_2021~~]]), follow the link to '''[[Bethe-Salpeter solver: SLEPC]]''' then '''return to this tutorial'''		If/Once you have a Yambo version compiled with the SLEPc, or you have the Virtual Machine or the Docker (with the yambo-gcc_openmp_petsc [[CECAM_VIRTUAL_2021 \| container]]), follow the link to '''[[Bethe-Salpeter solver: SLEPC]]''' then '''return to this tutorial'''

	==Summary==		==Summary==

Myrta at 08:31, 13 April 2021

2021-04-13T08:31:52Z

← Older revision		Revision as of 08:31, 13 April 2021
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	'''Optional:'''		'''Optional:'''
	Advanced users can recompile Yambo with the ''--enable-slepc-linalg'' option if they hadn't done so.		Advanced users can recompile Yambo with the ''--enable-slepc-linalg'' option if they hadn't done so.
	If/Once you have a Yambo version compiled with the SLEPc, or you have the Virtual Machine or the Docker (), follow the link to '''[[Bethe-Salpeter solver: SLEPC]]''' then '''return to this tutorial'''		If/Once you have a Yambo version compiled with the SLEPc, or you have the Virtual Machine or the Docker (with the yambo-gcc_openmp_petsc [[container \| CECAM_VIRTUAL_2021]]), follow the link to '''[[Bethe-Salpeter solver: SLEPC]]''' then '''return to this tutorial'''

	==Summary==		==Summary==

Myrta at 08:30, 13 April 2021

2021-04-13T08:30:09Z

← Older revision		Revision as of 08:30, 13 April 2021
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	'''Optional:'''		'''Optional:'''
	Advanced users can recompile Yambo with the ''--enable-slepc-linalg'' option if they hadn't done so.		Advanced users can recompile Yambo with the ''--enable-slepc-linalg'' option if they hadn't done so.
	If/Once you have a Yambo version compiled with the SLEPc, or you have the Virtual Machine or the ~~docker~~, follow the link to '''[[Bethe-Salpeter solver: SLEPC]]''' then '''return to this tutorial'''		If/Once you have a Yambo version compiled with the SLEPc, or you have the Virtual Machine or the Docker (), follow the link to '''[[Bethe-Salpeter solver: SLEPC]]''' then '''return to this tutorial'''

	==Summary==		==Summary==

Fulvio: /* SLEPc solver */

2021-04-07T15:02:47Z

SLEPc solver

← Older revision		Revision as of 15:02, 7 April 2021
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	'''Optional:'''		'''Optional:'''
	Advanced users can recompile Yambo with the ''--enable-slepc-linalg'' option.		Advanced users can recompile Yambo with the ''--enable-slepc-linalg'' option if they hadn't done so.
	If/Once you have a Yambo version compiled with the SLEPc, or you have the Virtual Machine or the docker, follow the link to '''[[Bethe-Salpeter solver: SLEPC]]''' then '''return to this tutorial'''		If/Once you have a Yambo version compiled with the SLEPc, or you have the Virtual Machine or the docker, follow the link to '''[[Bethe-Salpeter solver: SLEPC]]''' then '''return to this tutorial'''

Fulvio: /* SLEPc solver */

2021-04-07T15:01:31Z

SLEPc solver

← Older revision		Revision as of 15:01, 7 April 2021
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	This solver outputs the individual exciton energies and composition about an energy value chosen by the user. It can be applied to medium-large systems but does not provide the overall spectrum. This solver is typically used after obtaining the spectra from the Lanczos-Haydock solver to either analyze a specific peak or getting the energy and composition of a few low-lying excitons. It can be used for large-medium systems. The computational cost grows with the number of excitons one asks to compute.		This solver outputs the individual exciton energies and composition about an energy value chosen by the user. It can be applied to medium-large systems but does not provide the overall spectrum. This solver is typically used after obtaining the spectra from the Lanczos-Haydock solver to either analyze a specific peak or getting the energy and composition of a few low-lying excitons. It can be used for large-medium systems. The computational cost grows with the number of excitons one asks to compute.

	~~The SLEPc is currently not included in the default installation, so this option is not available on the docker or the Yambo installation with default compilation options.~~

	'''Optional:'''		'''Optional:'''
	Advanced users can recompile Yambo with the ''--enable-slepc-linalg'' option.		Advanced users can recompile Yambo with the ''--enable-slepc-linalg'' option.
	If/Once you have a Yambo version compiled with the SLEPc, or you have the Virtual Machine, follow the link to '''[[Bethe-Salpeter solver: SLEPC]]''' then '''return to this tutorial'''		If/Once you have a Yambo version compiled with the SLEPc, or you have the Virtual Machine or the docker, follow the link to '''[[Bethe-Salpeter solver: SLEPC]]''' then '''return to this tutorial'''

	==Summary==		==Summary==