occ::qm::PackedDFStore Class Reference

Three-centre integrals (μν|P) over the screened canonical shell pairs (q <= p, as IntegralEngine::shellpairs()), packed: one contiguous np x nq block per stored shell pair, every auxiliary function a column. More...

#include <df_packed_store.h>

Classes
struct	Block

Public Types
using	ShellPairList = std::vector<std::vector<size_t>>

Public Member Functions
void	build (IntegralEngine &engine, const CoulombMetric &metric, size_t max_bytes=unlimited)
	Stores the pairs that fit max_bytes, from engine at its current operator, and folds metric in when all of them fit.
void	clear ()
bool	built () const
bool	empty () const
bool	complete () const
	Every screened pair is stored, and the metric is folded in.
size_t	bytes () const
size_t	num_aux () const
	Auxiliary columns: fewer than the auxiliary basis once folded with a metric whose eigendecomposition fallback dropped vectors.
const ShellPairList &	unstored () const
Mat	contract (const std::vector< Mat > &densities) const
	Column c: sum over the stored pairs of D_c(μ,ν) B(μν,P), each D_c a symmetric nbf x nbf matrix.
std::vector< Mat >	expand (const Mat &x) const
	Matrix c: sum_P B(μν,P) x(P,c) over the stored pairs, symmetric.
std::vector< Mat >	exchange (const std::vector< Mat > &C, const std::vector< std::pair< int, int > > &pairs) const
	sum_P (B_P C_s)(B_P C_t)^T for every requested (s, t), on a complete store.
Mat	half_transform (Eigen::Ref< const Mat > C_left, Eigen::Ref< const Mat > C_right) const
	B(i*nR + a, P) = sum_μν C_left(μ,i) C_right(ν,a) B_P(μν) on a complete store, i.e.

Static Public Member Functions
static size_t	bytes_for (const gto::AOBasis &basis, const ShellPairList &shellpairs, size_t naux)
	Bytes of a store holding every pair of shellpairs.

Static Public Attributes
static constexpr size_t	unlimited = std::numeric_limits<size_t>::max()

Detailed Description

Three-centre integrals (μν|P) over the screened canonical shell pairs (q <= p, as IntegralEngine::shellpairs()), packed: one contiguous np x nq block per stored shell pair, every auxiliary function a column.

Pairs the shell-pair screen drops are never stored, and only one triangle is, so the store is a fraction of the dense nbf x nbf x naux one.

Under a byte budget only some pairs are stored – those most expensive to recompute per byte first – and unstored() lists the rest for the caller to compute directly. A complete store is folded with the Coulomb metric as soon as it is built, B = (μν|P) L^-T, so exchange and the correlated methods need no metric solve; a partial store keeps the raw integrals.

Member Typedef Documentation

ShellPairList

using occ::qm::PackedDFStore::ShellPairList = std::vector<std::vector<size_t>>

Member Function Documentation

build()

void occ::qm::PackedDFStore::build	(	IntegralEngine &	engine,
		const CoulombMetric &	metric,
		size_t	max_bytes = unlimited )

Stores the pairs that fit max_bytes, from engine at its current operator, and folds metric in when all of them fit.

built()

bool occ::qm::PackedDFStore::built ( ) const

inline

bytes()

size_t occ::qm::PackedDFStore::bytes ( ) const

inline

bytes_for()

size_t occ::qm::PackedDFStore::bytes_for ( const gto::AOBasis & basis, const ShellPairList & shellpairs, size_t naux )

static

Bytes of a store holding every pair of shellpairs.

clear()

void occ::qm::PackedDFStore::clear

(

)

complete()

bool occ::qm::PackedDFStore::complete ( ) const

inline

Every screened pair is stored, and the metric is folded in.

contract()

Mat occ::qm::PackedDFStore::contract

(

const std::vector< Mat > &

densities

)

const

Column c: sum over the stored pairs of D_c(μ,ν) B(μν,P), each D_c a symmetric nbf x nbf matrix.

empty()

bool occ::qm::PackedDFStore::empty ( ) const

inline

exchange()

std::vector< Mat > occ::qm::PackedDFStore::exchange	(	const std::vector< Mat > &	C,
		const std::vector< std::pair< int, int > > &	pairs ) const

sum_P (B_P C_s)(B_P C_t)^T for every requested (s, t), on a complete store.

Returns one nbf x nbf matrix per pair.

expand()

std::vector< Mat > occ::qm::PackedDFStore::expand

(

const Mat &

x

)

const

Matrix c: sum_P B(μν,P) x(P,c) over the stored pairs, symmetric.

half_transform()

Mat occ::qm::PackedDFStore::half_transform	(	Eigen::Ref< const Mat >	C_left,
		Eigen::Ref< const Mat >	C_right ) const

B(i*nR + a, P) = sum_μν C_left(μ,i) C_right(ν,a) B_P(μν) on a complete store, i.e.

the metric-folded MO three-index tensor (nL*nR x num_aux).

num_aux()

size_t occ::qm::PackedDFStore::num_aux ( ) const

inline

Auxiliary columns: fewer than the auxiliary basis once folded with a metric whose eigendecomposition fallback dropped vectors.

unstored()

const ShellPairList & occ::qm::PackedDFStore::unstored ( ) const

inline

Member Data Documentation

unlimited

size_t occ::qm::PackedDFStore::unlimited = std::numeric_limits<size_t>::max()

staticconstexpr

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

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