occ::mults::SFunctions Class Reference

S-functions for multipole interaction evaluation. More...

#include <sfunctions.h>

Classes
struct	SFunctionResult

Public Member Functions
	SFunctions (int max_rank=4)
	Constructor.
void	set_coordinates (const Vec3 &ra, const Vec3 &rb)
	Set the coordinate system.
void	set_coordinate_system (const CoordinateSystem &coords)
	Set the coordinate system directly.
const CoordinateSystem &	coordinate_system () const
	Get the current coordinate system.
SFunctions	swap_sites () const
	Create a new SFunctions object with swapped site coordinates.
void	compute_with_swap (int t1, int t2, int j, int level, SFunctionResult &result, bool swap) const
	Compute S-function with automatic coordinate swapping.
SFunctionResult	compute_s_function (int t1, int t2, int j, int level=0) const
	Compute S-function for given multipole indices.
std::vector< SFunctionResult >	compute_s_functions (const std::vector< std::tuple< int, int, int > > &indices, int level=0) const
	Compute multiple S-functions in batch.
std::pair< int, int >	index_to_lm (int index) const
	Convert linear multipole index to (l,m) quantum numbers.
double	rax () const
double	ray () const
double	raz () const
double	rbx () const
double	rby () const
double	rbz () const
double	r () const
double	raw_rax () const
double	raw_ray () const
double	raw_raz () const
double	raw_rbx () const
double	raw_rby () const
double	raw_rbz () const
double	dx () const
double	dy () const
double	dz () const
double	cxx () const
double	cxy () const
double	cxz () const
double	cyx () const
double	cyy () const
double	cyz () const
double	czx () const
double	czy () const
double	czz () const

Static Public Attributes
static constexpr int	MAX_S_FUNCTIONS = 400
static constexpr int	NUM_FIRST_DERIVS = 15
static constexpr int	NUM_SECOND_DERIVS = 120
static constexpr int	S1_CXX = 6
static constexpr int	S1_CXY = 7
static constexpr int	S1_CXZ = 8
static constexpr int	S1_CYX = 9
static constexpr int	S1_CYY = 10
static constexpr int	S1_CYZ = 11
static constexpr int	S1_CZX = 12
static constexpr int	S1_CZY = 13
static constexpr int	S1_CZZ = 14

Detailed Description

S-functions for multipole interaction evaluation.

This class computes the S-functions used in multipole electrostatic interactions, following the formulation used in Orient.

The S-functions represent the geometric part of multipole interactions for different combinations of multipole ranks and orientations.

Coordinate system:

• Site A coordinates: (rax, ray, raz)
• Site B coordinates: (rbx, rby, rbz)
• Distance vector: rb - ra

S-function notation: S(t1, t2, j)

• t1: multipole index for site A
• t2: multipole index for site B
  
• j: combined rank parameter

Constructor & Destructor Documentation

SFunctions()

occ::mults::SFunctions::SFunctions ( int  max_rank = 4 )

explicit

Constructor.

Parameters

max_rank

Maximum multipole rank to handle

Member Function Documentation

compute_s_function()

SFunctionResult occ::mults::SFunctions::compute_s_function	(	int	t1,
		int	t2,
		int	j,
		int	level = 0
	)		const

Compute S-function for given multipole indices.

Parameters

t1	Multipole index for site A
t2	Multipole index for site B
j	Combined rank parameter
level	Derivative level (0=value only, 1=first derivs, 2=second derivs)

Returns

S-function result with value and derivatives

compute_s_functions()

std::vector< SFunctionResult > occ::mults::SFunctions::compute_s_functions	(	const std::vector< std::tuple< int, int, int > > &	indices,
		int	level = 0
	)		const

Compute multiple S-functions in batch.

Parameters

indices	Vector of (t1, t2, j) triplets
level	Derivative level

Returns

Vector of S-function results

compute_with_swap()

void occ::mults::SFunctions::compute_with_swap	(	int	t1,
		int	t2,
		int	j,
		int	level,
		SFunctionResult &	result,
		bool	swap
	)		const

Compute S-function with automatic coordinate swapping.

This helper method automatically handles coordinate swapping when needed. If swap=true, it creates a swapped SFunctions object and computes S(t2, t1) instead of S(t1, t2), effectively reusing kernels for reverse orderings.

Parameters

t1	First multipole index
t2	Second multipole index
j	Combined angular momentum
level	Derivative level (0=S0, 1=S0+S1, 2=S0+S1+S2)
result	Output result structure
swap	If true, swap coordinates and call S(t2, t1)

coordinate_system()

const CoordinateSystem & occ::mults::SFunctions::coordinate_system ( ) const

inline

Get the current coordinate system.

cxx()

double occ::mults::SFunctions::cxx ( ) const

inline

cxy()

double occ::mults::SFunctions::cxy ( ) const

inline

cxz()

double occ::mults::SFunctions::cxz ( ) const

inline

cyx()

double occ::mults::SFunctions::cyx ( ) const

inline

cyy()

double occ::mults::SFunctions::cyy ( ) const

inline

cyz()

double occ::mults::SFunctions::cyz ( ) const

inline

czx()

double occ::mults::SFunctions::czx ( ) const

inline

czy()

double occ::mults::SFunctions::czy ( ) const

inline

czz()

double occ::mults::SFunctions::czz ( ) const

inline

dx()

double occ::mults::SFunctions::dx ( ) const

inline

dy()

double occ::mults::SFunctions::dy ( ) const

inline

dz()

double occ::mults::SFunctions::dz ( ) const

inline

index_to_lm()

std::pair< int, int > occ::mults::SFunctions::index_to_lm

(

int

index

)

const

Convert linear multipole index to (l,m) quantum numbers.

Parameters

index

Linear index

Returns

(l,m) pair

r()

double occ::mults::SFunctions::r ( ) const

inline

raw_rax()

double occ::mults::SFunctions::raw_rax ( ) const

inline

raw_ray()

double occ::mults::SFunctions::raw_ray ( ) const

inline

raw_raz()

double occ::mults::SFunctions::raw_raz ( ) const

inline

raw_rbx()

double occ::mults::SFunctions::raw_rbx ( ) const

inline

raw_rby()

double occ::mults::SFunctions::raw_rby ( ) const

inline

raw_rbz()

double occ::mults::SFunctions::raw_rbz ( ) const

inline

rax()

double occ::mults::SFunctions::rax ( ) const

inline

ray()

double occ::mults::SFunctions::ray ( ) const

inline

raz()

double occ::mults::SFunctions::raz ( ) const

inline

rbx()

double occ::mults::SFunctions::rbx ( ) const

inline

rby()

double occ::mults::SFunctions::rby ( ) const

inline

rbz()

double occ::mults::SFunctions::rbz ( ) const

inline

set_coordinate_system()

void occ::mults::SFunctions::set_coordinate_system

(

const CoordinateSystem &

coords

)

Set the coordinate system directly.

Parameters

coords

CoordinateSystem (may include body-frame transformations)

set_coordinates()

void occ::mults::SFunctions::set_coordinates	(	const Vec3 &	ra,
		const Vec3 &	rb
	)

Set the coordinate system.

Parameters

ra	Position of site A
rb	Position of site B

swap_sites()

SFunctions occ::mults::SFunctions::swap_sites

(

)

const

Create a new SFunctions object with swapped site coordinates.

Returns a new SFunctions where site A and site B are swapped. This is used to compute S(t1@A, t2@B) as S(t2@B', t1@A') where A' and B' are the swapped positions.

Returns

SFunctions with ra and rb swapped

Member Data Documentation

MAX_S_FUNCTIONS

constexpr int occ::mults::SFunctions::MAX_S_FUNCTIONS = 400

staticconstexpr

NUM_FIRST_DERIVS

constexpr int occ::mults::SFunctions::NUM_FIRST_DERIVS = 15

staticconstexpr

NUM_SECOND_DERIVS

constexpr int occ::mults::SFunctions::NUM_SECOND_DERIVS = 120

staticconstexpr

S1_CXX

constexpr int occ::mults::SFunctions::S1_CXX = 6

staticconstexpr

S1_CXY

constexpr int occ::mults::SFunctions::S1_CXY = 7

staticconstexpr

S1_CXZ

constexpr int occ::mults::SFunctions::S1_CXZ = 8

staticconstexpr

S1_CYX

constexpr int occ::mults::SFunctions::S1_CYX = 9

staticconstexpr

S1_CYY

constexpr int occ::mults::SFunctions::S1_CYY = 10

staticconstexpr

S1_CYZ

constexpr int occ::mults::SFunctions::S1_CYZ = 11

staticconstexpr

S1_CZX

constexpr int occ::mults::SFunctions::S1_CZX = 12

staticconstexpr

S1_CZY

constexpr int occ::mults::SFunctions::S1_CZY = 13

staticconstexpr

S1_CZZ

constexpr int occ::mults::SFunctions::S1_CZZ = 14

staticconstexpr

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

• /home/runner/work/occ/occ/include/occ/mults/sfunctions.h