LFOCKACE: Difference between revisions
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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}}=.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}}=. | 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 tags and articles == | == Related tags and articles == | ||
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{{TAG|AGGAC}}, | {{TAG|AGGAC}}, | ||
{{TAG|LHFCALC}}, | {{TAG|LHFCALC}}, | ||
[[list_of_hybrid_functionals| | [[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 tag]][[Category:Exchange-correlation functionals]][[Category:Hybrid_functionals | [[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 of the Fock exchange matrix is calculated and the adaptively compressed exchange operator 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 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