Molecular block-grid construction

Classes
class	excgrid::RadialGrid
class	excgrid::AngularGrid
struct	excgrid::GridParams
struct	excgrid::Block
class	excgrid::BlockGrid

Functions
static Result< RadialGrid >	excgrid::RadialGrid::Create (std::size_t pointCount, double alpha, std::size_t exponent=2)
std::size_t	excgrid::RadialGrid::Size () const noexcept
std::span< const double >	excgrid::RadialGrid::Points () const noexcept
std::span< const double >	excgrid::RadialGrid::Weights () const noexcept
static Result< AngularGrid >	excgrid::AngularGrid::Create (std::size_t pointCount)
std::size_t	excgrid::AngularGrid::Size () const noexcept
std::size_t	excgrid::AngularGrid::Degree () const noexcept
std::array< double, 3 >	excgrid::AngularGrid::Point (std::size_t index) const noexcept
double	excgrid::AngularGrid::Weight (std::size_t index) const noexcept
static Result< BlockGrid >	excgrid::BlockGrid::Create (const Geometry &geometry, const GridParams &params={})
std::size_t	excgrid::BlockGrid::BlockCount () const noexcept
std::span< const Block >	excgrid::BlockGrid::Blocks () const noexcept
std::size_t	excgrid::BlockGrid::TotalPointCount () const noexcept

Variables
static constexpr std::span< const std::size_t, internal::kLebedevSizeCount >	excgrid::AngularGrid::kAvailableSizes
	The available point counts, smallest first.
std::size_t	excgrid::GridParams::radialPoints = 75
	Radial points per atom.
std::size_t	excgrid::GridParams::angularPoints = 302
	A Lebedev size (AngularGrid::kAvailableSizes).
double	excgrid::GridParams::alpha = 0.5
	Radial mapping scale, Bohr.
std::size_t	excgrid::GridParams::radialExponent = 2
	The MHL mapping exponent m.
double	excgrid::GridParams::trimWeight = 1e-15
	Points with |weight| below this are dropped.
std::size_t	excgrid::GridParams::blockTarget = 1024
	Spatial re-batching target (points per block).
std::size_t	excgrid::Block::pointCount = 0
	Points in the block.
std::vector< std::array< double, 3 > >	excgrid::Block::points
	pointCount positions, Bohr.
std::vector< double >	excgrid::Block::weights
	pointCount quadrature weights.
std::vector< std::size_t >	excgrid::Block::atomIndex
	pointCount owning atoms.

Detailed Description

The radial and angular quadratures, the Becke fuzzy-cell partition, and the trimmed, spatially re-batched molecular blocks the kernel consumers walk (docs/kernel-api.md section 5).

Function Documentation

BlockCount()

std::size_t excgrid::BlockGrid::BlockCount ( ) const

inlinenodiscardnoexcept

The number of blocks.

Returns

The block count.

Blocks()

std::span< const Block > excgrid::BlockGrid::Blocks ( ) const

inlinenodiscardnoexcept

The blocks, in iteration order.

Returns

The block span.

Create() [1/3]

Result< AngularGrid > excgrid::AngularGrid::Create ( std::size_t pointCount )

static

Creates the quadrature with the given point count.

Parameters

pointCount

A size from kAvailableSizes.

Returns

The grid, or kInvalidArgument for a non-Lebedev count.

Create() [2/3]

Result< BlockGrid > excgrid::BlockGrid::Create ( const Geometry & geometry, const GridParams & params = {} )

static

Builds the grid for the geometry.

Parameters

geometry	The molecule whose atoms center the sub-grids.
params	The build parameters.

Returns

The grid, or an Error from the underlying quadratures.

Create() [3/3]

Result< RadialGrid > excgrid::RadialGrid::Create ( std::size_t pointCount, double alpha, std::size_t exponent = 2 )

static

Creates the quadrature.

Parameters

pointCount	Radial points; the outermost lies at r_max.
alpha	Length scale of the mapping (Bohr).
exponent	The mapping exponent m; 2 is the standard choice.

Returns

The grid, or kInvalidArgument for a zero point count or a zero exponent.

Degree()

std::size_t excgrid::AngularGrid::Degree ( ) const

inlinenodiscardnoexcept

The algebraic degree of exactness of the quadrature.

Returns

The exactness degree.

Point()

std::array< double, 3 > excgrid::AngularGrid::Point ( std::size_t index ) const

nodiscardnoexcept

The unit-sphere node at index (Bohr-free unit vector).

Parameters

index

The node index in [0, Size()).

Returns

The node triple.

Points()

std::span< const double > excgrid::RadialGrid::Points ( ) const

inlinenodiscardnoexcept

The radial points, innermost first.

Returns

The point span (Bohr).

Size() [1/2]

std::size_t excgrid::AngularGrid::Size ( ) const

inlinenodiscardnoexcept

The number of quadrature nodes.

Returns

The node count.

Size() [2/2]

std::size_t excgrid::RadialGrid::Size ( ) const

inlinenodiscardnoexcept

The radial point count.

Returns

The point count.

TotalPointCount()

std::size_t excgrid::BlockGrid::TotalPointCount ( ) const

inlinenodiscardnoexcept

The total point count across all blocks.

Returns

The total point count.

Weight()

double excgrid::AngularGrid::Weight ( std::size_t index ) const

nodiscardnoexcept

The node weight at index (weights sum to 4 pi).

Parameters

index

The node index in [0, Size()).

Returns

The weight.

Weights()

std::span< const double > excgrid::RadialGrid::Weights ( ) const

inlinenodiscardnoexcept

The radial weights (Jacobian included, no r^2 factor).

Returns

The weight span.

Variable Documentation

kAvailableSizes

std::span<const std::size_t, internal::kLebedevSizeCount> excgrid::AngularGrid::kAvailableSizes

staticconstexpr

Initial value:

                                       =
internal::kLebedevSizes

The available point counts, smallest first.