Estimator for impact point calculations. More...

#include <acts/blob/master/Core/include/Acts/Vertexing/ImpactPointEstimator.hpp>

Collaboration diagram for Acts::ImpactPointEstimator< input_track_t, propagator_t, propagator_options_t >:

Classes
struct	Config

Public Member Functions
	ImpactPointEstimator (const Config &cfg)
	Constructor.

Result< double >	calculate3dDistance (const GeometryContext &gctx, const BoundParameters &trkParams, const Vector3D &vtxPos) const
	Calculates 3D distance between a track and a 3D point.

Result< std::unique_ptr< const BoundParameters > >	estimate3DImpactParameters (const GeometryContext &gctx, const Acts::MagneticFieldContext &mctx, const BoundParameters &trkParams, const Vector3D &vtxPos) const
	Creates track parameters bound to plane at point of closest approach in 3d to given reference position. The parameters and errors are defined on the plane intersecting the track at point of closest approach, with track orthogonal to the plane and center of the plane defined as the given reference point (vertex).

Result< double >	get3dVertexCompatibility (const GeometryContext &gctx, const BoundParameters *trkParams, const Vector3D &vertexPos) const
	Estimates the compatibility of a track to a vertex position based on the 3d distance between the track and the vertex.

Result< ImpactParametersAndSigma >	estimateImpactParameters (const BoundParameters &track, const Vertex< input_track_t > &vtx, const GeometryContext &gctx, const MagneticFieldContext &mctx) const
	Estimates the impact parameters and their errors of a given track w.r.t. a vertex by propagating the trajectory state towards the vertex position.

Private Types
using	BField_t = typename propagator_t::Stepper::BField

Private Member Functions
Result< double >	performNewtonApproximation (const Vector3D &trkPos, const Vector3D &vtxPos, double phi, double theta, double r) const
	Performs a Newton approximation to retrieve a point of closest approach in 3D to a reference position.

Result< void >	getDistanceAndMomentum (const GeometryContext &gctx, const BoundParameters &trkParams, const Vector3D &vtxPos, Vector3D &deltaR, Vector3D &momDir) const
	Helper function to calculate relative distance between track and vtxPos and the direction of the momentum.

Private Attributes
const Config	m_cfg
	Configuration object.

Detailed Description

template<typename input_track_t, typename propagator_t, typename propagator_options_t = PropagatorOptions<>>
class Acts::ImpactPointEstimator< input_track_t, propagator_t, propagator_options_t >

Estimator for impact point calculations.

Definition at line 39 of file ImpactPointEstimator.hpp.

View newest version in sPHENIX GitHub at line 39 of file ImpactPointEstimator.hpp

Member Typedef Documentation

template<typename input_track_t, typename propagator_t, typename propagator_options_t = PropagatorOptions<>>

using Acts::ImpactPointEstimator< input_track_t, propagator_t, propagator_options_t >::BField_t = typename propagator_t::Stepper::BField

private

Definition at line 40 of file ImpactPointEstimator.hpp.

View newest version in sPHENIX GitHub at line 40 of file ImpactPointEstimator.hpp

Constructor & Destructor Documentation

template<typename input_track_t, typename propagator_t, typename propagator_options_t = PropagatorOptions<>>

Acts::ImpactPointEstimator< input_track_t, propagator_t, propagator_options_t >::ImpactPointEstimator ( const Config & cfg )

inline

Constructor.

Parameters

cfg	Configuration object

Definition at line 77 of file ImpactPointEstimator.hpp.

View newest version in sPHENIX GitHub at line 77 of file ImpactPointEstimator.hpp

Member Function Documentation

template<typename input_track_t , typename propagator_t , typename propagator_options_t >

Acts::Result< double > Acts::ImpactPointEstimator< input_track_t, propagator_t, propagator_options_t >::calculate3dDistance	(	const GeometryContext &	gctx,
		const BoundParameters &	trkParams,
		const Vector3D &	vtxPos
	)		const

Calculates 3D distance between a track and a 3D point.

Parameters

gctx	The geometry context
trkParams	Track parameters
vtxPos	Position to calculate distance to

Returns: Distance

Definition at line 19 of file ImpactPointEstimator.ipp.

View newest version in sPHENIX GitHub at line 19 of file ImpactPointEstimator.ipp

References deltaR().

Referenced by Acts::Test::BOOST_AUTO_TEST_CASE().

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template<typename input_track_t , typename propagator_t , typename propagator_options_t >

Acts::Result< std::unique_ptr< const Acts::BoundParameters > > Acts::ImpactPointEstimator< input_track_t, propagator_t, propagator_options_t >::estimate3DImpactParameters	(	const GeometryContext &	gctx,
		const Acts::MagneticFieldContext &	mctx,
		const BoundParameters &	trkParams,
		const Vector3D &	vtxPos
	)		const

Creates track parameters bound to plane at point of closest approach in 3d to given reference position. The parameters and errors are defined on the plane intersecting the track at point of closest approach, with track orthogonal to the plane and center of the plane defined as the given reference point (vertex).

Parameters

gctx	The geometry context
mctx	The magnetic field context
trkParams	Track parameters
vtxPos	Reference position (vertex)

Returns: New track params

Definition at line 39 of file ImpactPointEstimator.ipp.

View newest version in sPHENIX GitHub at line 39 of file ImpactPointEstimator.ipp

References Acts::backward, and deltaR().

Referenced by Acts::Test::BOOST_AUTO_TEST_CASE().

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template<typename input_track_t, typename propagator_t , typename propagator_options_t >

Acts::Result< Acts::ImpactParametersAndSigma > Acts::ImpactPointEstimator< input_track_t, propagator_t, propagator_options_t >::estimateImpactParameters	(	const BoundParameters &	track,
		const Vertex< input_track_t > &	vtx,
		const GeometryContext &	gctx,
		const MagneticFieldContext &	mctx
	)		const

Estimates the impact parameters and their errors of a given track w.r.t. a vertex by propagating the trajectory state towards the vertex position.

Parameters

track	Track to estimate IP from
vtx	Vertex the track belongs to
gctx	The geometry context
mctx	The magnetic field context

Definition at line 246 of file ImpactPointEstimator.ipp.

View newest version in sPHENIX GitHub at line 246 of file ImpactPointEstimator.ipp

Referenced by Acts::Test::BOOST_AUTO_TEST_CASE().

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template<typename input_track_t , typename propagator_t , typename propagator_options_t >

Acts::Result< double > Acts::ImpactPointEstimator< input_track_t, propagator_t, propagator_options_t >::get3dVertexCompatibility	(	const GeometryContext &	gctx,
		const BoundParameters *	trkParams,
		const Vector3D &	vertexPos
	)		const

Estimates the compatibility of a track to a vertex position based on the 3d distance between the track and the vertex.

Parameters

gctx	The Geometry context
track	Track parameters at point of closest approach in 3d as retrieved by estimate3DImpactParameters
vertexPos	The vertex position

Returns: The compatibility value

Definition at line 90 of file ImpactPointEstimator.ipp.

View newest version in sPHENIX GitHub at line 90 of file ImpactPointEstimator.ipp

References Acts::SingleTrackParameters< ChargePolicy >::covariance(), Acts::eX, Acts::eY, Acts::SingleTrackParameters< ChargePolicy >::parameters(), Acts::SingleBoundTrackParameters< ChargePolicy >::referenceSurface(), and Acts::Surface::transform().

Referenced by Acts::Test::BOOST_AUTO_TEST_CASE().

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template<typename input_track_t , typename propagator_t , typename propagator_options_t >

Acts::Result< void > Acts::ImpactPointEstimator< input_track_t, propagator_t, propagator_options_t >::getDistanceAndMomentum	(	const GeometryContext &	gctx,
		const BoundParameters &	trkParams,
		const Vector3D &	vtxPos,
		Vector3D &	deltaR,
		Vector3D &	momDir
	)		const

private

Helper function to calculate relative distance between track and vtxPos and the direction of the momentum.

Parameters

gctx	The geometry context
trkParams	Track parameters
vtxPos	The vertex position
deltaR	Relative position between track and vtxPos, to be determined by method
momDir	Momentum direction, to be determined by method

Definition at line 188 of file ImpactPointEstimator.ipp.

View newest version in sPHENIX GitHub at line 188 of file ImpactPointEstimator.ipp

References kdfinder::abs(), Acts::Surface::center(), Acts::eLOC_D0, Acts::eLOC_Z0, Acts::ePHI, Acts::eQOP, Acts::eTHETA, Acts::eZ, Acts::SingleTrackParameters< ChargePolicy >::parameters(), phi, r, Acts::SingleBoundTrackParameters< ChargePolicy >::referenceSurface(), theta(), and G4InuclParticleNames::z0.

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template<typename input_track_t , typename propagator_t , typename propagator_options_t >

Acts::Result< double > Acts::ImpactPointEstimator< input_track_t, propagator_t, propagator_options_t >::performNewtonApproximation	(	const Vector3D &	trkPos,
		const Vector3D &	vtxPos,
		double	phi,
		double	theta,
		double	r
	)		const

private

Performs a Newton approximation to retrieve a point of closest approach in 3D to a reference position.

Parameters

trkPos	Initial position
vtxPos	Reference position
phi	Phi along the helix which will be changed by the Newton method
theta	Track theta
r	Helix radius

Returns: New phi value

Definition at line 132 of file ImpactPointEstimator.ipp.

View newest version in sPHENIX GitHub at line 132 of file ImpactPointEstimator.ipp

References kdfinder::abs(), phi, and G4InuclParticleNames::z0.

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Member Data Documentation

template<typename input_track_t, typename propagator_t, typename propagator_options_t = PropagatorOptions<>>

const Config Acts::ImpactPointEstimator< input_track_t, propagator_t, propagator_options_t >::m_cfg

private

Configuration object.

Definition at line 136 of file ImpactPointEstimator.hpp.

View newest version in sPHENIX GitHub at line 136 of file ImpactPointEstimator.hpp

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

acts/blob/master/Core/include/Acts/Vertexing/ImpactPointEstimator.hpp
acts/blob/master/Core/include/Acts/Vertexing/ImpactPointEstimator.ipp

Classes

Public Member Functions

Private Types

Private Member Functions

Private Attributes

Detailed Description

template<typename input_track_t, typename propagator_t, typename propagator_options_t = PropagatorOptions<>> class Acts::ImpactPointEstimator< input_track_t, propagator_t, propagator_options_t >

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

template<typename input_track_t, typename propagator_t, typename propagator_options_t = PropagatorOptions<>>
class Acts::ImpactPointEstimator< input_track_t, propagator_t, propagator_options_t >