Acts::PolynomialBetheHeitlerApprox Class Reference

This class approximates the Bethe-Heitler distribution as a gaussian mixture. More...

#include <Acts/TrackFitting/BetheHeitlerApprox.hpp>

Inheritance diagram for Acts::PolynomialBetheHeitlerApprox:

Collaboration diagram for Acts::PolynomialBetheHeitlerApprox:

Classes
struct	PolyData
	Polynomial coefficient sets for a Gaussian mixture component. More...
struct	RangeData
	Single x/x0 range with its data and transformation flag. More...

Public Types
using	Data = std::vector<PolyData>
	Type alias for array of polynomial data for all components.
Public Types inherited from Acts::BetheHeitlerApprox
using	Component = detail::GaussianComponent
	Type alias for Gaussian mixture component.

Public Member Functions
	PolynomialBetheHeitlerApprox (const Data &lowData, const Data &highData, bool lowTransform, bool highTransform, double lowLimit, double highLimit, bool clampToRange, double noChangeLimit, double singleGaussianLimit)
	Construct the Bethe-Heitler approximation description with two parameterizations, one for lower ranges, one for higher ranges.
	PolynomialBetheHeitlerApprox (std::vector< RangeData > ranges, bool clampToRange, double noChangeLimit, double singleGaussianLimit)
	Construct the Bethe-Heitler approximation description with N ranges.
std::size_t	maxComponents () const override
	Returns the number of components the returned mixture will have.
std::span< Component >	mixture (double xOverX0, const std::span< Component > mixture) const override
	Generates the mixture from the polynomials and reweights them, so that the sum of all weights is 1.
bool	validXOverX0 (const double xOverX0) const override
	Checks if an input is valid for the parameterization.

Detailed Description

This class approximates the Bethe-Heitler distribution as a gaussian mixture.

To enable an approximation for continuous input variables, the weights, means and variances are internally parametrized as a Nth order polynomial.

Constructor & Destructor Documentation

PolynomialBetheHeitlerApprox() [1/2]

Acts::PolynomialBetheHeitlerApprox::PolynomialBetheHeitlerApprox	(	std::vector< RangeData >	ranges,
		bool	clampToRange,
		double	noChangeLimit,
		double	singleGaussianLimit )

Construct the Bethe-Heitler approximation description with N ranges.

Each range has its own data and transformation flag. The ranges will be sorted by minimum value and validated for non-overlapping.

Parameters

ranges	Vector of range data
clampToRange	whether to clamp the input x/x0 to the allowed range
noChangeLimit	limit below which no change is applied
singleGaussianLimit	limit below which a single Gaussian is used

PolynomialBetheHeitlerApprox() [2/2]

Acts::PolynomialBetheHeitlerApprox::PolynomialBetheHeitlerApprox	(	const Data &	lowData,
		const Data &	highData,
		bool	lowTransform,
		bool	highTransform,
		double	lowLimit,
		double	highLimit,
		bool	clampToRange,
		double	noChangeLimit,
		double	singleGaussianLimit )

Construct the Bethe-Heitler approximation description with two parameterizations, one for lower ranges, one for higher ranges.

Is it assumed that the lower limit of the high-x/x0 data is equal to the upper limit of the low-x/x0 data.

Parameters

lowData	data for the lower x/x0 range
highData	data for the higher x/x0 range
lowTransform	whether the low data need to be transformed
highTransform	whether the high data need to be transformed
lowLimit	the upper limit for the low data
highLimit	the upper limit for the high data
clampToRange	whether to clamp the input x/x0 to the allowed range
noChangeLimit	limit below which no change is applied
singleGaussianLimit	limit below which a single Gaussian is used

Deprecated

Use constructor taking std::vector<RangeData> instead

Member Function Documentation

maxComponents()

std::size_t Acts::PolynomialBetheHeitlerApprox::maxComponents ( ) const

overridevirtual

Returns the number of components the returned mixture will have.

Returns

Number of components in the mixture

Implements Acts::BetheHeitlerApprox.

mixture()

std::span< Component > Acts::PolynomialBetheHeitlerApprox::mixture ( double xOverX0, const std::span< Component > mixture ) const

overridevirtual

Generates the mixture from the polynomials and reweights them, so that the sum of all weights is 1.

Parameters

xOverX0	pathlength in terms of the radiation length
mixture	preallocated array to store the result

Returns

the potentially modified input span containing the mixture

Implements Acts::BetheHeitlerApprox.

validXOverX0()

bool Acts::PolynomialBetheHeitlerApprox::validXOverX0 ( const double xOverX0 ) const

overridevirtual

Checks if an input is valid for the parameterization.

Parameters

xOverX0

pathlength in terms of the radiation length

Returns

True if x/x0 is within valid range for this parameterization

Implements Acts::BetheHeitlerApprox.