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Implement NEO-DFT on host

Open aodongliu opened this issue 2 years ago • 2 comments

This PR adds functionality to do electron-proton correlation (EPC) functional in GauXC, thus allowing nuclear-electronic orbital (NEO) DFT calculations.

Changes:

  • Modified loadBalancer to store 2 basis.

  • Modified XCIntegrator to also take a epcfunctional.

  • Added neo_eval_exc_vxc function is added. UKS is forced for protonic to ensure high spin configuration for protons. Electronic system can be either RKS or UKS.

  • Protonic basis screening, collocation evaluation, xmat evaluation, density evaluation... are all carried out using the existing machinery.

  • Available EPC functionals are: EPC17_1, EPC18_2, EPC18_1, EPC18_2. These are done using the Builtin backend of ExchCXX (https://github.com/wavefunction91/ExchCXX/pull/38).
    References: EPC17-1, EPC17-2, EPC18-1 and EPC18-2

  • EPC17_1, EPC17_2, EPC18_1, EPC18_2 functional is benchmarked against PySCF implementation. Settings: water molecule, H radius set to 52.9 pm, sto-3g/prot-sp basis, RB3LYP + unrestricted EPC functionals, (99,590) Lebedev grid with no pruning, MuraKnowles radial quadrature, and Becke weights. PySCF set to 1e-15 energy convergence, GauXC set to 1e-10 RMSDP convergence

Functionals EPC17_1 EPC17_2 EPC18_1 EPC18_2
GauXC -75.2922851028909 -75.2315058326807 -75.2885522845334 -75.2269730022946
PySCF -75.2922851084361 -75.2315058383013 -75.2885522900691 -75.2269730078668

  • EPC17_2 functional is additionally benchmarked against Chronus Quantum implementation. Settings: COH2 molecule, H radius set to 52.9 pm, cc-pvdz/prot-pb4-d basis, RBLYP + unrestricted EPC17_2 functionals, (99,590) Lebedev grid with no pruning, MurrayHandyLeming radial quadrature, and Becke weights. CQ and GauXC set to 1e-10 RMSDP convergence

      CQ:        SCF Completed: E(R-) = -114.4472478253 Eh after 192 SCF Iterations
  GauXC:     SCF Completed: E(R-) = -114.4472478253 Eh after 192 SCF Iterations

  • Device code NYI

aodongliu avatar Nov 30 '23 19:11 aodongliu

Note that epc17 and epc18 are available in libxc master

susilehtola avatar Nov 30 '23 20:11 susilehtola

NEO DFT PR is ready for review (in-house epc is used right now. API for libxc via exchcxx will come later).

MPI tests are failing at the moment. However, if protonic screening is turned off, then MPI can recover the same energy as single node

aodongliu avatar Jan 06 '24 21:01 aodongliu