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ELPH WF CACHE PREFILL: Difference between revisions

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Description: Pre-fills the wavefunction cache before the main electron-phonon loop begins.
Description: Pre-fills the wavefunction cache before the main electron-phonon loop begins.
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* {{TAG|ELPH_WF_REDISTRIBUTE}}
* {{TAG|ELPH_WF_REDISTRIBUTE}}
* {{TAG|ELPH_WF_COMM_OPT}}
* {{TAG|ELPH_WF_COMM_OPT}}
* {{TAG|ELPH_MELS}}
[[Category:INCAR tag]][[Category:Electron-phonon_interactions]]
[[Category:INCAR tag]][[Category:Electron-phonon_interactions]]

Revision as of 12:54, 18 June 2026

Template:DISPLAYTITLE ELPH_WF_CACHE_PREFILL = logical
Default: ELPH_WF_CACHE_PREFILL = .TRUE. 

Description: Pre-fills the wavefunction cache before the main electron-phonon loop begins.


When computing electron-phonon matrix elements, VASP caches wavefunctions fetched from remote MPI ranks (see ELPH_WF_CACHE_MB). With ELPH_WF_CACHE_PREFILL = .TRUE. (the default), all required wavefunctions are gathered into the cache in a single communication phase before the main loop starts. This means the loop itself runs with little or no inter-rank MPI traffic.

Setting ELPH_WF_CACHE_PREFILL = .FALSE. disables pre-filling; wavefunctions are then fetched on demand during the loop. This reduces the upfront communication cost but increases total MPI traffic and is generally slower.

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