LFOCKACE: Difference between revisions

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 $X=LL^\dagger$ of the Fock exchange matrix $X_{ij} = \langle \tilde\psi_i \mid \tilde V_X \mid \tilde\psi_j \rangle$ is calculated and the adaptively compressed exchange operator $\tilde V_{ACE} = -\sum_i \mid \tilde X_i \rangle \langle \tilde X_i \mid$ 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 $\approx 3$ 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.

References

↑ ^a ^b L. Lin, J. Chem. Theory Comput. 12, 2242-2249 (2016).

[linlin:jctc:2016-1] L. Lin, J. Chem. Theory Comput. 12, 2242-2249 (2016).

[1]

@@ Line 6: / Line 6: @@
 *N.B.:Available for CPU and OpenACC version of VASP.6 when compiled with [[Precompiler flags|-Dfock_dblbuf]].
 ----
-For {{TAGBL|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 [[Hartree-Fock_and_HF/DFT_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 {{TAGBL|LFOCKACE}}=.TRUE. the conventional orbital representation is used.
+For {{TAG|LFOCKACE}}=.FALSE. the conventional orbital representation is used.
-== Related Tags and Sections ==
+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 ==
 {{TAG|AEXX}},
 {{TAG|AEXX}},
@@ Line 16: / Line 18: @@
 {{TAG|AGGAC}},
 {{TAG|LHFCALC}},
-[[list_of_hybrid_functionals|settings for specific hybrid functionals]]
+[[list_of_hybrid_functionals|List of hybrid functionals]],
+[[Hybrid_functionals:_formalism|Hybrid functionals: formalism]]
 {{sc|LHFCALC|Examples|Examples that use this tag}}
@@ Line 24: / Line 27: @@
 ----
-[[Category:INCAR]][[Category:XC Functionals]][[Category:Hybrids]][[Category:VASP6]]
+[[Category:INCAR tag]][[Category:Exchange-correlation functionals]][[Category:Hybrid_functionals]]