Add initial exact exchange implementation #942
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Co-authored-by: bkaperick <[email protected]>
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@antoine-levitt Thoughts or blockers ? |
| """ | ||
| function model_HF(lattice::AbstractMatrix, atoms::Vector{<:Element}, | ||
| positions::Vector{<:AbstractVector}; extra_terms=[], kwargs...) | ||
| @warn "Exact exchange in DFTK is hardly optimised and not yet production-ready." |
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put that check in the instantiation of the exchange term?
| @@ -0,0 +1,76 @@ | |||
| @doc raw""" | |||
| Exact exchange term: the Hartree-Exact exchange energy of the orbitals | |||
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calling it hartree is confusing?
| # ABINIT/src/66_wfs/m_getghc.F90 | ||
| # ABINIT/src/66_wfs/m_fock_getghc.F90 | ||
| # ABINIT/src/66_wfs/m_prep_kgb.F90 | ||
| # ABINIT/src/66_wfs/m_bandfft_kpt.F90 |
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I'd rather not give explicit references to code (as that might give the impression that we reproduced the implementation instead of a clean-room reimplementation)
| # https://journals.aps.org/prb/pdf/10.1103/PhysRevB.73.205119 | ||
| # https://journals.aps.org/prb/pdf/10.1103/PhysRevB.77.193110 | ||
| # https://docs.abinit.org/topics/documents/hybrids-2017.pdf (Abinit apparently | ||
| # uses a short-ranged Coulomb) |
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Yeah that we should meet and think about, also with @ELallinec who is thinking about the Coulomb singularity
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Definitely as a first attempt it's reasonable to have a short-ranged Coulomb.
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Have you tested this in any way? I'm reluctant to merge something that might just be flat out wrong, esp. with the Coulomb singularity. Maybe H2? |
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Is this even converging at all? There's basically no damping on the Fock exchange by doing it this way. Direct minimization OTOH should work outside the box |
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Roadmap after discussion:
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Small overhowl of #717.