LDIAG - Revision history

Huebsch at 12:15, 17 October 2024

2024-10-17T12:15:19Z

← Older revision		Revision as of 12:15, 17 October 2024
Line 1:		Line 1:
	{{TAGDEF\|LDIAG\|[logical]\|.TRUE.}}		{{TAGDEF\|LDIAG\|[logical]\|.TRUE.}}

	Description: ~~This tag determines~~ whether a subspace diagonalization is performed ~~or not~~ within the ~~main~~ algorithm selected by {{TAG\|ALGO}} or {{TAG\|IALGO}}.		Description: Determines whether a subspace diagonalization is performed within the algorithm selected by {{TAG\|ALGO}} or {{TAG\|IALGO}}.
	----		----
	For {{TAG\|ALGO}} = <tt>Normal</tt>, <tt>Fast</tt>, and <tt>VeryFast</tt>, VASP performs a diagonalization in the subspace spanned by all orbitals. This is often referred to as the [https://en.wikipedia.org/wiki/Rayleigh%E2%80%93Ritz_method Rayleigh–Ritz method].		For {{TAG\|ALGO}} = <tt>Normal</tt>, <tt>Fast</tt>, and <tt>VeryFast</tt>, VASP performs a diagonalization in the subspace spanned by all orbitals. This is often referred to as the [https://en.wikipedia.org/wiki/Rayleigh%E2%80%93Ritz_method Rayleigh–Ritz method].
Line 35:		Line 35:

	{{sc\|LDIAG\|Examples\|Examples that use this tag}}		{{sc\|LDIAG\|Examples\|Examples that use this tag}}
	~~----~~

	[[Category:INCAR tag]][[Category:Electronic minimization]]		[[Category:INCAR tag]][[Category:Electronic minimization]]

Karsai: /* Related Tags and Sections */

2022-04-08T14:30:07Z

Related Tags and Sections

← Older revision		Revision as of 14:30, 8 April 2022
Line 30:		Line 30:
	{{NB\|warning\| {{TAG\|ALGO}} {{=}} <tt>VeryFast</tt> is not supported for hybrid functionals. }}		{{NB\|warning\| {{TAG\|ALGO}} {{=}} <tt>VeryFast</tt> is not supported for hybrid functionals. }}

	== Related ~~Tags~~ and ~~Sections~~ ==		== Related tags and articles ==
	{{TAG\|IALGO}},		{{TAG\|IALGO}},
	{{TAG\|ALGO}}		{{TAG\|ALGO}}
Line 36:		Line 36:
	{{sc\|LDIAG\|Examples\|Examples that use this tag}}		{{sc\|LDIAG\|Examples\|Examples that use this tag}}
	----		----
	~~[[The_VASP_Manual\|Contents]]~~

	[[Category:INCAR]][[Category:Electronic minimization]]		[[Category:INCAR tag]][[Category:Electronic minimization]]

Huebsch at 13:46, 6 April 2022

2022-04-06T13:46:44Z

← Older revision		Revision as of 13:46, 6 April 2022
Line 19:		Line 19:

	For the algorithms {{TAG\|ALGO}} = <tt>Normal</tt> or <tt>Fast</tt>, by construction it is not possible to switch off subspace diagonalization, as these algorithms require subspace diagonalizations during the iterative refinement of the orbitals.		For the algorithms {{TAG\|ALGO}} = <tt>Normal</tt> or <tt>Fast</tt>, by construction it is not possible to switch off subspace diagonalization, as these algorithms require subspace diagonalizations during the iterative refinement of the orbitals.
	Furthermore, algorithms that minimize the total energy ({{TAG\|ALGO}} = <tt>All</tt>) are often too "greedy" and tend to alternate the orbital order in the course of the ~~scf~~ cycle and energy optimization.		Furthermore, algorithms that minimize the total energy ({{TAG\|ALGO}} = <tt>All</tt>) are often too "greedy" and tend to alternate the orbital order in the course of the SCF cycle and energy optimization.

	In summary, the following combinations are potentially useful:		In summary, the following combinations are potentially useful:
Line 28:		Line 28:

	Other combinations using {{TAG\|LDIAG}} = <tt>.FALSE.</tt> are likely to yield undesirable results.		Other combinations using {{TAG\|LDIAG}} = <tt>.FALSE.</tt> are likely to yield undesirable results.
	~~Finally, note that~~ {{TAG\|ALGO}} = <tt>VeryFast</tt> is not supported for hybrid functionals.		{{NB\|warning\| {{TAG\|ALGO}} {{=}} <tt>VeryFast</tt> is not supported for hybrid functionals. }}

	== Related Tags and Sections ==		== Related Tags and Sections ==
Line 38:		Line 38:
	[[The_VASP_Manual\|Contents]]		[[The_VASP_Manual\|Contents]]

	[[Category:INCAR]][[Category:Electronic ~~Minimization]][[Category:Electronic Minimization Methods~~]]		[[Category:INCAR]][[Category:Electronic minimization]]

Kresse at 11:14, 10 November 2021

2021-11-10T11:14:15Z

← Older revision		Revision as of 11:14, 10 November 2021
Line 23:		Line 23:
	In summary, the following combinations are potentially useful:		In summary, the following combinations are potentially useful:

	ALGO = VeryFast ; LDIAG = .FALSE		ALGO = VeryFast ; LDIAG = .FALSE.

	ALGO = Damped ; LDIAG = .FALSE		ALGO = Damped ; LDIAG = .FALSE.

	Other combinations using {{TAG\|LDIAG}} = <tt>.FALSE.</tt> are likely to yield undesirable results.		Other combinations using {{TAG\|LDIAG}} = <tt>.FALSE.</tt> are likely to yield undesirable results.

Vaspmaster at 09:56, 10 November 2021

2021-11-10T09:56:26Z

← Older revision		Revision as of 09:56, 10 November 2021
Line 1:		Line 1:
	{{TAGDEF\|LDIAG\|[logical]\|.TRUE.}}		{{TAGDEF\|LDIAG\|[logical]\|.TRUE.}}

	Description: This tag determines whether a subspace diagonalization is performed or not within the main algorithm selected by {{TAG\|IALGO}}.		Description: This tag determines whether a subspace diagonalization is performed or not within the main algorithm selected by {{TAG\|ALGO}} or {{TAG\|IALGO}}.
	----		----
	For {{TAG\|ALGO}} = <tt>Normal</tt>, <tt>Fast</tt>, and <tt>VeryFast</tt>, VASP performs a diagonalization in the subspace spanned by all orbitals. This is often referred to as the [https://en.wikipedia.org/wiki/Rayleigh%E2%80%93Ritz_method Rayleigh–Ritz method].		For {{TAG\|ALGO}} = <tt>Normal</tt>, <tt>Fast</tt>, and <tt>VeryFast</tt>, VASP performs a diagonalization in the subspace spanned by all orbitals. This is often referred to as the [https://en.wikipedia.org/wiki/Rayleigh%E2%80%93Ritz_method Rayleigh–Ritz method].

Vaspmaster at 09:55, 10 November 2021

2021-11-10T09:55:23Z

← Older revision		Revision as of 09:55, 10 November 2021
Line 3:		Line 3:
	Description: This tag determines whether a subspace diagonalization is performed or not within the main algorithm selected by {{TAG\|IALGO}}.		Description: This tag determines whether a subspace diagonalization is performed or not within the main algorithm selected by {{TAG\|IALGO}}.
	----		----
	For {{TAG\|ALGO}}=Normal, Fast, and VeryFast, VASP performs a diagonalization in the subspace spanned by all orbitals. This is often referred to as the [https://en.wikipedia.org/wiki/Rayleigh%E2%80%93Ritz_method Rayleigh–Ritz method].		For {{TAG\|ALGO}} = <tt>Normal</tt>, <tt>Fast</tt>, and <tt>VeryFast</tt>, VASP performs a diagonalization in the subspace spanned by all orbitals. This is often referred to as the [https://en.wikipedia.org/wiki/Rayleigh%E2%80%93Ritz_method Rayleigh–Ritz method].
	This step increases the convergence rate and thus is expedient in most cases.		This step increases the convergence rate and thus is expedient in most cases.
	Furthermore, the subspace diagonalization sorts the orbital/eigenvalues in ascending order.		Furthermore, the subspace diagonalization sorts the orbital/eigenvalues in ascending order.

Vaspmaster at 09:43, 10 November 2021

2021-11-10T09:43:28Z

← Older revision		Revision as of 09:43, 10 November 2021
Line 3:		Line 3:
	Description: This tag determines whether a subspace diagonalization is performed or not within the main algorithm selected by {{TAG\|IALGO}}.		Description: This tag determines whether a subspace diagonalization is performed or not within the main algorithm selected by {{TAG\|IALGO}}.
	----		----
	For {{TAG\|ALGO}}=Normal, Fast, and VeryFast, VASP performs a diagonalization in the subspace spanned by all orbitals. This is often referred to as ~~Rayleigh–Ritz method (~~https://en.wikipedia.org/wiki/Rayleigh%E2%80%93Ritz_method).		For {{TAG\|ALGO}}=Normal, Fast, and VeryFast, VASP performs a diagonalization in the subspace spanned by all orbitals. This is often referred to as the [https://en.wikipedia.org/wiki/Rayleigh%E2%80%93Ritz_method Rayleigh–Ritz method].
	~~The~~ step increases the convergence rate and thus is expedient in most cases.		This step increases the convergence rate and thus is expedient in most cases.
	~~For the direct optimization algorithms (for instance ALGO = All or Damped), a subspace diagonalization is usually not performed, but in order to improve~~		Furthermore, the subspace diagonalization sorts the orbital/eigenvalues in ascending order.
	~~the accuracy of the calculated forces, after convergence has been reached one single diagonalization in the subspace spanned by all orbitals is performed.~~
	~~Note~~, ~~that~~ the subspace diagonalization sorts the orbital/eigenvalues in ascending order.

	For ~~{{TAG\|ALGO}} = VeryFast and Damped it is possible to switch off the subspace diagonalization by specifying {{TAG\|LDIAG}}=.FALSE. in~~ the ~~{{TAG\|INCAR}} file. Specifically,~~ for {{TAG\|ALGO}} = ~~VeryFast~~, ~~LDIAG= .FALSE. changes from an exact Rayleigh–Ritz~~ diagonalization ~~to Loewdin perturbation theory.~~		For the direct optimization algorithms (for instance {{TAG\|ALGO}} = <tt>All</tt> or <tt>Damped</tt>),
	~~Loewdin perturbation theory strictly conserves the orbital order~~, ~~i.e. say the n.th orbital will remain stored~~ in the ~~n.th storage slot and only small rotations into that orbital can occur. For {{TAG\|ALGO}} = Damped and All,~~ the ~~final sub space diagonalization is simply skipped if LDIAG=.FALSE. is set. Generally using {{TAG\|LDIAG}} = .FALSE. is only advised~~, if one ~~wants to maintain a certain orbital order, for instance, when reading~~ the orbitals ~~from an existing {{TAG\|WAVECAR}} file~~.		a subspace diagonalization is usually not performed, but in order to improve the accuracy of the calculated forces,
			after convergence has been reached one single diagonalization in the subspace spanned by all orbitals is performed.

	For the algorithms {{TAG\|ALGO}}=Normal or Fast, by construction it is not possible to switch off subspace diagonalization, as these algorithms require subspace diagonalizations during the iterative refinement of the orbitals. Furthermore, algorithms that minimize the total energy (ALGO = All) are often too "greedy" and tend to alternate the orbital order in the course of the scf cycle and energy optimization.		For {{TAG\|ALGO}} = <tt>VeryFast</tt> and <tt>Damped</tt> it is possible to switch off the subspace diagonalization by specifying {{TAG\|LDIAG}} = <tt>.FALSE.</tt> in the {{FILE\|INCAR}} file.
			Specifically, for {{TAG\|ALGO}} = <tt>VeryFast</tt>, {{TAG\|LDIAG}} = <tt>.FALSE.</tt> changes from an exact Rayleigh–Ritz diagonalization to Loewdin perturbation theory.

			Note, Loewdin perturbation theory strictly conserves the orbital order, ''i.e.'', the ''n''-th orbital will remain stored in the ''n''-th storage slot and only small rotations into that orbital can occur.
			For {{TAG\|ALGO}} = <tt>Damped</tt> and <tt>All</tt>, the final subspace diagonalization is simply skipped if {{TAG\|LDIAG}} = <tt>.FALSE.</tt> is set.
			Generally using {{TAG\|LDIAG}} = <tt>.FALSE.</tt> is only advised, if one wants to maintain a certain orbital order, for instance, when reading the orbitals from an existing {{FILE\|WAVECAR}} file.

			For the algorithms {{TAG\|ALGO}} = <tt>Normal</tt> or <tt>Fast</tt>, by construction it is not possible to switch off subspace diagonalization, as these algorithms require subspace diagonalizations during the iterative refinement of the orbitals.
			Furthermore, algorithms that minimize the total energy ({{TAG\|ALGO}} = <tt>All</tt>) are often too "greedy" and tend to alternate the orbital order in the course of the scf cycle and energy optimization.

	In summary, the following combinations are potentially useful:		In summary, the following combinations are potentially useful:

	ALGO = VeryFast ; LDIAG = .FALSE		ALGO = VeryFast ; LDIAG = .FALSE

	ALGO = Damped ; LDIAG = .FALSE		ALGO = Damped ; LDIAG = .FALSE
	Other combinations using LDIAG = .FALSE. are likely to ~~result in~~ undesirable results. Finally, note that ALGO = VeryFast is not supported for hybrid functionals.
			Other combinations using {{TAG\|LDIAG}} = <tt>.FALSE.</tt> are likely to yield undesirable results.
			Finally, note that {{TAG\|ALGO}} = <tt>VeryFast</tt> is not supported for hybrid functionals.

	== Related Tags and Sections ==		== Related Tags and Sections ==

Kresse at 07:39, 10 November 2021

2021-11-10T07:39:29Z

← Older revision		Revision as of 07:39, 10 November 2021
Line 18:		Line 18:

	ALGO = Damped ; LDIAG = .FALSE		ALGO = Damped ; LDIAG = .FALSE
	Other combinations using LDIAG = .FALSE. are likely to result in undesirable results. Finally, note that ALGO = VeryFast is not ~~working~~ for hybrid functionals.		Other combinations using LDIAG = .FALSE. are likely to result in undesirable results. Finally, note that ALGO = VeryFast is not supported for hybrid functionals.

	== Related Tags and Sections ==		== Related Tags and Sections ==

Kresse at 07:29, 10 November 2021

2021-11-10T07:29:40Z

← Older revision		Revision as of 07:29, 10 November 2021
Line 12:		Line 12:
	Loewdin perturbation theory strictly conserves the orbital order, i.e. say the n.th orbital will remain stored in the n.th storage slot and only small rotations into that orbital can occur. For {{TAG\|ALGO}} = Damped and All, the final sub space diagonalization is simply skipped if LDIAG=.FALSE. is set. Generally using {{TAG\|LDIAG}} = .FALSE. is only advised, if one wants to maintain a certain orbital order, for instance, when reading the orbitals from an existing {{TAG\|WAVECAR}} file.		Loewdin perturbation theory strictly conserves the orbital order, i.e. say the n.th orbital will remain stored in the n.th storage slot and only small rotations into that orbital can occur. For {{TAG\|ALGO}} = Damped and All, the final sub space diagonalization is simply skipped if LDIAG=.FALSE. is set. Generally using {{TAG\|LDIAG}} = .FALSE. is only advised, if one wants to maintain a certain orbital order, for instance, when reading the orbitals from an existing {{TAG\|WAVECAR}} file.

	For the algorithms {{TAG\|ALGO}}=Normal or Fast, by construction ~~of the algorithm~~ it is not possible to switch off subspace diagonalization, as these algorithms require subspace diagonalizations during the iterative refinement of the orbitals. Furthermore, algorithms that minimize the total energy (ALGO = All) are often too "greedy" and tend to alternate the orbital order in the course of the scf cycle and energy optimization.		For the algorithms {{TAG\|ALGO}}=Normal or Fast, by construction it is not possible to switch off subspace diagonalization, as these algorithms require subspace diagonalizations during the iterative refinement of the orbitals. Furthermore, algorithms that minimize the total energy (ALGO = All) are often too "greedy" and tend to alternate the orbital order in the course of the scf cycle and energy optimization.

	In summary, the following combinations are potentially useful:		In summary, the following combinations are potentially useful:

Kresse at 07:22, 10 November 2021

2021-11-10T07:22:06Z

← Older revision		Revision as of 07:22, 10 November 2021
Line 12:		Line 12:
	Loewdin perturbation theory strictly conserves the orbital order, i.e. say the n.th orbital will remain stored in the n.th storage slot and only small rotations into that orbital can occur. For {{TAG\|ALGO}} = Damped and All, the final sub space diagonalization is simply skipped if LDIAG=.FALSE. is set. Generally using {{TAG\|LDIAG}} = .FALSE. is only advised, if one wants to maintain a certain orbital order, for instance, when reading the orbitals from an existing {{TAG\|WAVECAR}} file.		Loewdin perturbation theory strictly conserves the orbital order, i.e. say the n.th orbital will remain stored in the n.th storage slot and only small rotations into that orbital can occur. For {{TAG\|ALGO}} = Damped and All, the final sub space diagonalization is simply skipped if LDIAG=.FALSE. is set. Generally using {{TAG\|LDIAG}} = .FALSE. is only advised, if one wants to maintain a certain orbital order, for instance, when reading the orbitals from an existing {{TAG\|WAVECAR}} file.

	For the algorithms {{TAG\|ALGO}}=Normal or Fast, by construction of the algorithm it is not possible to switch off subspace diagonalization, as these algorithms require subspace diagonalizations during the iterative refinement of the orbitals. Furthermore, algorithms that minimize the total energy (ALGO = All) are often too "greedy" and tend to alternate the orbital order in the course of the scf cycle and energy optimization.		For the algorithms {{TAG\|ALGO}}=Normal or Fast, by construction of the algorithm it is not possible to switch off subspace diagonalization, as these algorithms require subspace diagonalizations during the iterative refinement of the orbitals. Furthermore, algorithms that minimize the total energy (ALGO = All) are often too "greedy" and tend to alternate the orbital order in the course of the scf cycle and energy optimization.

			In summary, the following combinations are potentially useful:
			ALGO = VeryFast ; LDIAG = .FALSE

			ALGO = Damped ; LDIAG = .FALSE
			Other combinations using LDIAG = .FALSE. are likely to result in undesirable results. Finally, note that ALGO = VeryFast is not working for hybrid functionals.

	== Related Tags and Sections ==		== Related Tags and Sections ==
	{{TAG\|IALGO}},		{{TAG\|IALGO}},