Acts::HoughVertexFinder< spacepoint_t >::Config Struct Reference

Configuration struct. More...

#include <Acts/Vertexing/HoughVertexFinder.hpp>

Collaboration diagram for Acts::HoughVertexFinder< spacepoint_t >::Config:

Public Attributes
std::vector< double >	absEtaFractions {0.4f, 0.6f}
	The amount of measurements in the |eta| range expressed as a fraction of all measurements within the whole |eta| range.
std::vector< double >	absEtaRanges {2., 4.}
	The algorithm dynamically choose |eta| range necessary to have a reasonable precision, based on the distribution of the measurements.
double	binsCotThetaDecrease = 1.35f
	If the actual number of measurements is below "targetSPs", then the number of bins along cot(theta)-axis decreases.
Vector3	defVtxPosition
	Default position of the vertex in X, Y, and Z coordinates.
std::uint32_t	fillNeighbours = 0
	Number of neighbouring bins in Hough plane to fill in the cot(theta) direction.
double	maxAbsEta = 4.0f
	Maximum absolute pseudorapidity for vertex finding.
double	minAbsEta = 0.3f
	Minimum and maximum ranges in |eta|; the |eta| will not be set outside these bounds even if targetSPs is not reached.
std::uint32_t	minHits = 4
	Minimum number of hits in Hough plane to consider the cell to contain a track.
std::vector< std::uint32_t >	nBinsCotThetaIterZ {8000, 8000, 8000}
	Number of bins along cot(theta)-axis of the Hough image for each iteration.
std::vector< std::uint32_t >	nBinsZIterZ {800, 180, 80}
	Number of bins along z-axis of the Hough image for each iteration.
std::uint32_t	peakWidth = 3
	Width of the peak when estimating vertex position.
std::vector< double >	rangeIterZ
	The algorithm starts peak searching considering wide range in Z and then iteratively constrain itself to narrower ranges around previously found peak.
std::uint32_t	targetSPs = 10000
	Ideal amount of spacepoints; |eta| range will be limited to contain approximately this amount of SPs.

Detailed Description

template<typename spacepoint_t>
struct Acts::HoughVertexFinder< spacepoint_t >::Config

Configuration struct.

Member Data Documentation

absEtaFractions

template<typename spacepoint_t>

std::vector<double> Acts::HoughVertexFinder< spacepoint_t >::Config::absEtaFractions {0.4f, 0.6f}

The amount of measurements in the |eta| range expressed as a fraction of all measurements within the whole |eta| range.

Measurements are assumed to be distributed uniformly with the |eta| range.

absEtaRanges

template<typename spacepoint_t>

std::vector<double> Acts::HoughVertexFinder< spacepoint_t >::Config::absEtaRanges {2., 4.}

The algorithm dynamically choose |eta| range necessary to have a reasonable precision, based on the distribution of the measurements.

The first |eta| range starts at 0., the others start at the endpoint of the previous range.

binsCotThetaDecrease

template<typename spacepoint_t>

double Acts::HoughVertexFinder< spacepoint_t >::Config::binsCotThetaDecrease = 1.35f

If the actual number of measurements is below "targetSPs", then the number of bins along cot(theta)-axis decreases.

Thus, the actual number of bins can be smaller than stated in "nBinsCotThetaIterZ". For every magnitude (in natural logarithm) below targetSPs, the number of bins in cot(theta) will decrease by this factor.

defVtxPosition

template<typename spacepoint_t>

Vector3 Acts::HoughVertexFinder< spacepoint_t >::Config::defVtxPosition

Initial value:

{0. * UnitConstants::mm, 0. * UnitConstants::mm,
                           0. * UnitConstants::mm}

Default position of the vertex in X, Y, and Z coordinates.

fillNeighbours

template<typename spacepoint_t>

std::uint32_t Acts::HoughVertexFinder< spacepoint_t >::Config::fillNeighbours = 0

Number of neighbouring bins in Hough plane to fill in the cot(theta) direction.

maxAbsEta

template<typename spacepoint_t>

double Acts::HoughVertexFinder< spacepoint_t >::Config::maxAbsEta = 4.0f

Maximum absolute pseudorapidity for vertex finding.

minAbsEta

template<typename spacepoint_t>

double Acts::HoughVertexFinder< spacepoint_t >::Config::minAbsEta = 0.3f

Minimum and maximum ranges in |eta|; the |eta| will not be set outside these bounds even if targetSPs is not reached.

minHits

template<typename spacepoint_t>

std::uint32_t Acts::HoughVertexFinder< spacepoint_t >::Config::minHits = 4

Minimum number of hits in Hough plane to consider the cell to contain a track.

nBinsCotThetaIterZ

template<typename spacepoint_t>

std::vector<std::uint32_t> Acts::HoughVertexFinder< spacepoint_t >::Config::nBinsCotThetaIterZ {8000, 8000, 8000}

Number of bins along cot(theta)-axis of the Hough image for each iteration.

nBinsZIterZ

template<typename spacepoint_t>

std::vector<std::uint32_t> Acts::HoughVertexFinder< spacepoint_t >::Config::nBinsZIterZ {800, 180, 80}

Number of bins along z-axis of the Hough image for each iteration.

peakWidth

template<typename spacepoint_t>

std::uint32_t Acts::HoughVertexFinder< spacepoint_t >::Config::peakWidth = 3

Width of the peak when estimating vertex position.

rangeIterZ

template<typename spacepoint_t>

std::vector<double> Acts::HoughVertexFinder< spacepoint_t >::Config::rangeIterZ

Initial value:

{200. * UnitConstants::mm,
                                   30. * UnitConstants::mm,
                                   16. * UnitConstants::mm}

The algorithm starts peak searching considering wide range in Z and then iteratively constrain itself to narrower ranges around previously found peak.

At the same time it may adapt other Hough-image parameters in each step.

targetSPs

template<typename spacepoint_t>

std::uint32_t Acts::HoughVertexFinder< spacepoint_t >::Config::targetSPs = 10000

Ideal amount of spacepoints; |eta| range will be limited to contain approximately this amount of SPs.