occ::qm::Guess Struct Reference

The starting point a guess produces. More...

#include <initial_guess.h>

Collaboration diagram for occ::qm::Guess:

Public Attributes
GuessKind	kind {GuessKind::Core}
Mat	density
	Spin-summed density normalised to half the electron count – occ's usual convention – expressed in density_basis.
gto::AOBasis	density_basis
	The basis density is expressed in.
bool	density_in_orbital_basis {false}
	Whether density_basis is the orbital basis itself, in which case the caller wants a plain density-driven Fock build.
bool	density_is_shell_diagonal {false}
	Whether density is block-diagonal over the shells of density_basis, which the mixed-basis Fock build uses to skip integrals.
Mat	potential
	One-electron potential to add to the core Hamiltonian, in the orbital basis.

Detailed Description

The starting point a guess produces.

A guess perturbs the core Hamiltonian in one of two ways, so it hands back either a density to build a Fock matrix from or a one-electron potential to add. Core supplies neither, leaving F = H.

Member Data Documentation

density

Mat occ::qm::Guess::density

Spin-summed density normalised to half the electron count – occ's usual convention – expressed in density_basis.

Empty for Core and Sap.

density_basis

gto::AOBasis occ::qm::Guess::density_basis

The basis density is expressed in.

Soad builds in the minimal basis, so the caller has to project; every other kind uses the orbital basis, where the projection is the identity.

density_in_orbital_basis

bool occ::qm::Guess::density_in_orbital_basis {false}

Whether density_basis is the orbital basis itself, in which case the caller wants a plain density-driven Fock build.

Routing that case through the mixed-basis build instead pays for an identity projection: it duplicates every shell as auxiliary and runs the four-index loop over the doubled set.

density_is_shell_diagonal

bool occ::qm::Guess::density_is_shell_diagonal {false}

Whether density is block-diagonal over the shells of density_basis, which the mixed-basis Fock build uses to skip integrals.

True only for Soad, whose occupations are diagonal by construction.

kind

GuessKind occ::qm::Guess::kind {GuessKind::Core}

potential

Mat occ::qm::Guess::potential

One-electron potential to add to the core Hamiltonian, in the orbital basis.

Only Sap sets it, and it sets no density.

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The documentation for this struct was generated from the following file:

• /home/runner/work/occ/occ/include/occ/qm/initial_guess.h