README.md

This directory provides routines that are used to generate the code in src/core/xc_fallback. The intention is to be able to quickly add a pure-Julia fallback implementation for simple functionals, such that calculations in deviating precision or using non-standard Array types can be performed. For the standard case DFTK still relies on libxc via Libxc.jl.

The generators in this folder are based upon the Maple code generators used by libxc in order to implement its exchange-correlation functionals. Currently the generation procedure only generates rough code, which needs to be manually edited in order to compile and to work. Thus a proper mass-generation of functionals would require a more sophisticated solution, but the implementation of selected important cases should be possible like so.