PRECFOCK: Difference between revisions
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Description: {{TAG|PRECFOCK}} controls the FFT grids used in the exact exchange routines (Hartree-Fock and hybrid functionals). | Description: {{TAG|PRECFOCK}} controls the FFT grids used in the exact exchange routines (Hartree-Fock and hybrid functionals). | ||
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::{| cellpadding="5" cellspacing="0" border="1" | |||
|{{TAG|PRECFOCK}} || FFT-grid || Augmentation charge || Quality | |||
|- | |||
| Low || G<sub>cut</sub> || identical to standard DFT || large noise in forces/energy errors | |||
|- | |||
| Medium || identical to std. FFT || identical to standard DFT || some noise in forces/good energy | |||
|- | |||
| Fast || G<sub>cut</sub> || very soft augmentation charge || some noise in forces/good energy | |||
|- | |||
| Normal || 3/2×G<sub>cut</sub> || soft augmentation charge || accurate forces and energy | |||
|- | |||
| Accurate || 2×G<sub>cut</sub> || soft augmentation charge || very accurate forces and energy | |||
|} | |||
== Related Tags and Sections == | == Related Tags and Sections == | ||
{{TAG|ENCUT}}, | {{TAG|ENCUT}}, | ||
Revision as of 13:05, 15 February 2011
PRECFOCK = Low | Medium | Fast | Normal | Accurate
Default: PRECFOCK = Normal
Description: PRECFOCK controls the FFT grids used in the exact exchange routines (Hartree-Fock and hybrid functionals).
PRECFOCK FFT-grid Augmentation charge Quality Low Gcut identical to standard DFT large noise in forces/energy errors Medium identical to std. FFT identical to standard DFT some noise in forces/good energy Fast Gcut very soft augmentation charge some noise in forces/good energy Normal 3/2×Gcut soft augmentation charge accurate forces and energy Accurate 2×Gcut soft augmentation charge very accurate forces and energy
Related Tags and Sections
ENCUT, hybrid functionals, settings for specific hybrid functionals