ODDONLY: Difference between revisions

From VASP Wiki
No edit summary
No edit summary
Line 30: Line 30:
----
----


[[Category:INCAR]][[Category:XC Functionals]][[Category:Hybrids]]
[[Category:INCAR]][[Category:XC Functionals]][[Category:Hybrids]][[Category:Many-body Perturbation Theory]]

Revision as of 14:20, 19 March 2019

ODDONLY = .TRUE. | .FALSE.
Default: ODDONLY = .FALSE. 

Description: ODDONLY=.TRUE. selects a subset of k-points for the representation of the Fock exchange potential, with C1=C2=C3=1, and n1+n2+n3 odd.


One may restrict the sum over q in the Fock exchange potential (or one of its short range counterparts) to a subset, {qk}, of the full (N1×N2×N3) k-point set, {k}, for which the following holds

where b1,2,3 are the reciprocal lattice vectors of the primitive cell, and Ci is the integer grid reduction factor along reciprocal lattice direction bi.

ODDONLY=.TRUE. selects a subset of k-points with C1=C2=C3=1, and n1+n2+n3 odd. It reduces the computational work load for HF type calculations by a factor two, but is only sensible for high symmetry cases (such as sc, fcc or bcc cells).

Mind: there are circumstances under which downsampling should not be used!

Related Tags and Sections

NKRED, NKREDX, NKREDY, NKREDZ, EVENONLY, downsampling, Hartree-Fock_and_HF/DFT_hybrid_functionals

Examples that use this tag