LFOCKACE: Difference between revisions
(Created page with "{{TAGDEF|LFOCKACE|.TRUE. {{!}} .FALSE. | .TRUE.}} Description: {{TAG|LHFCALC}} determines whether the Adaptively Compressed Exchange Operator is used.{{cite|linlin:jctc:2016}...") |
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{{TAGDEF|LFOCKACE|.TRUE. {{!}} .FALSE. | .TRUE.}} | {{TAGDEF|LFOCKACE|.TRUE. {{!}} .FALSE. | .TRUE.}} | ||
{{DEF|LFOCKACE|.TRUE.|for VASP.6|N/A|for VASP.5.X and older}} | |||
Description: {{TAG| | Description: {{TAG|LFOCKACE}} determines whether the Adaptively Compressed Exchange Operator is used.{{cite|linlin:jctc:2016}} | ||
*N.B.:Available for CPU and OpenACC version of VASP.6 when compiled with [[Precompiler flags|-Dfock_dblbuf]]. | |||
---- | ---- | ||
For {{TAG|LFOCKACE}}=.TRUE. the Cholesky decomposition <math>X=LL^\dagger</math> of the Fock exchange matrix <math>X_{ij} = \langle \tilde\psi_i \mid \tilde V_X \mid \tilde\psi_j \rangle </math> is calculated and the adaptively compressed exchange operator <math>\tilde V_{ACE} = -\sum_i \mid \tilde X_i \rangle \langle \tilde X_i \mid </math> is used for the action of the Fock exchange on the pseudo orbitals. This method can be used for [[:Category:Hybrid functionals|hybrid functionals]] in combination with the Davidson algorithm ({{TAGBL|ALGO}}=Normal) to save a factor of <math>\approx 3</math> in computation time. | |||
For {{TAG|LFOCKACE}}=.FALSE. the conventional orbital representation is used. | |||
Note: it is good scientific practice to cite the original publication (Ref. {{cite|linlin:jctc:2016}}) if you use this feature. The feature is used by default, if the Davidson algorithm ({{TAG|ALGO}} = Normal) is used; ACE is not used for {{TAG|ALGO}} = Damped or {{TAG|ALGO}} = All. | |||
== Related | == Related tags and articles == | ||
{{TAG|AEXX}}, | {{TAG|AEXX}}, | ||
{{TAG|AEXX}}, | {{TAG|AEXX}}, | ||
| Line 10: | Line 18: | ||
{{TAG|AGGAC}}, | {{TAG|AGGAC}}, | ||
{{TAG|LHFCALC}}, | {{TAG|LHFCALC}}, | ||
[[ | [[list_of_hybrid_functionals|List of hybrid functionals]], | ||
[[ | [[Hybrid_functionals:_formalism|Hybrid functionals: formalism]] | ||
{{sc|LHFCALC|Examples|Examples that use this tag}} | {{sc|LHFCALC|Examples|Examples that use this tag}} | ||
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---- | ---- | ||
[[Category:INCAR]][[Category: | [[Category:INCAR tag]][[Category:Exchange-correlation functionals]][[Category:Hybrid_functionals]] | ||
Latest revision as of 06:30, 21 February 2024
LFOCKACE = .TRUE. | .FALSE.
Default: LFOCKACE = .TRUE.
| Default: LFOCKACE | = .TRUE. | for VASP.6 |
| = N/A | for VASP.5.X and older |
Description: LFOCKACE determines whether the Adaptively Compressed Exchange Operator is used.[1]
- N.B.:Available for CPU and OpenACC version of VASP.6 when compiled with -Dfock_dblbuf.
For LFOCKACE=.TRUE. the Cholesky decomposition [math]\displaystyle{ X=LL^\dagger }[/math] of the Fock exchange matrix [math]\displaystyle{ X_{ij} = \langle \tilde\psi_i \mid \tilde V_X \mid \tilde\psi_j \rangle }[/math] is calculated and the adaptively compressed exchange operator [math]\displaystyle{ \tilde V_{ACE} = -\sum_i \mid \tilde X_i \rangle \langle \tilde X_i \mid }[/math] is used for the action of the Fock exchange on the pseudo orbitals. This method can be used for hybrid functionals in combination with the Davidson algorithm (ALGO=Normal) to save a factor of [math]\displaystyle{ \approx 3 }[/math] in computation time.
For LFOCKACE=.FALSE. the conventional orbital representation is used.
Note: it is good scientific practice to cite the original publication (Ref. [1]) if you use this feature. The feature is used by default, if the Davidson algorithm (ALGO = Normal) is used; ACE is not used for ALGO = Damped or ALGO = All.
Related tags and articles
AEXX, AEXX, AGGAX, AGGAC, LHFCALC, List of hybrid functionals, Hybrid functionals: formalism