Acts::StraightLineStepper Class Reference

straight line stepper based on Surface intersection More...

#include <acts/blob/sPHENIX/Core/include/Acts/Propagator/StraightLineStepper.hpp>

Classes
struct	State

Public Types
using	Jacobian = BoundMatrix
using	Covariance = BoundSymMatrix
using	BoundState = std::tuple< BoundTrackParameters, Jacobian, double >
using	CurvilinearState = std::tuple< CurvilinearTrackParameters, Jacobian, double >
using	BField = NullBField
using	state_type = State

Public Member Functions
	StraightLineStepper ()=default
	Constructor.
void	resetState (State &state, const BoundVector &boundParams, const BoundSymMatrix &cov, const Surface &surface, const NavigationDirection navDir=forward, const double stepSize=std::numeric_limits< double >::max()) const
	Resets the state.
Vector3D	getField (State &, const Vector3D &) const
Vector3D	position (const State &state) const
Vector3D	direction (const State &state) const
double	momentum (const State &state) const
double	charge (const State &state) const
double	time (const State &state) const
double	overstepLimit (const State &) const
Intersection3D::Status	updateSurfaceStatus (State &state, const Surface &surface, const BoundaryCheck &bcheck) const
template<typename object_intersection_t >
void	updateStepSize (State &state, const object_intersection_t &oIntersection, bool release=true) const
void	setStepSize (State &state, double stepSize, ConstrainedStep::Type stype=ConstrainedStep::actor) const
void	releaseStepSize (State &state) const
std::string	outputStepSize (const State &state) const
BoundState	boundState (State &state, const Surface &surface) const
	It does not check if the transported state is at the surface, this needs to be guaranteed by the propagator.
CurvilinearState	curvilinearState (State &state) const
	This creates a curvilinear state.
void	update (State &state, const FreeVector &parameters, const Covariance &covariance) const
void	update (State &state, const Vector3D &uposition, const Vector3D &udirection, double up, double time) const
void	covarianceTransport (State &state) const
void	covarianceTransport (State &state, const Surface &surface) const
template<typename propagator_state_t >
Result< double >	step (propagator_state_t &state) const

Detailed Description

straight line stepper based on Surface intersection

The straight line stepper is a simple navigation stepper to be used to navigate through the tracking geometry. It can be used for simple material mapping, navigation validation

Definition at line 35 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 35 of file StraightLineStepper.hpp

Member Typedef Documentation

using Acts::StraightLineStepper::BField = NullBField

Definition at line 42 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 42 of file StraightLineStepper.hpp

using Acts::StraightLineStepper::BoundState = std::tuple<BoundTrackParameters, Jacobian, double>

Definition at line 39 of file StraightLineStepper.hpp.

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

using Acts::StraightLineStepper::Covariance = BoundSymMatrix

Definition at line 38 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 38 of file StraightLineStepper.hpp

using Acts::StraightLineStepper::CurvilinearState = std::tuple<CurvilinearTrackParameters, Jacobian, double>

Definition at line 41 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 41 of file StraightLineStepper.hpp

using Acts::StraightLineStepper::Jacobian = BoundMatrix

Definition at line 37 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 37 of file StraightLineStepper.hpp

using Acts::StraightLineStepper::state_type = State

Always use the same propagation state type, independently of the initial track parameter type and of the target surface

Definition at line 138 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 138 of file StraightLineStepper.hpp

Constructor & Destructor Documentation

Acts::StraightLineStepper::StraightLineStepper ( )

default

Constructor.

Member Function Documentation

std::tuple< BoundTrackParameters, BoundMatrix, double > Acts::StraightLineStepper::boundState	(	State &	state,
		const Surface &	surface
	)		const

It does not check if the transported state is at the surface, this needs to be guaranteed by the propagator.

Create and return the bound state at the current position

Parameters

[in]	state	State that will be presented as BoundState
[in]	surface	The surface to which we bind the state

Returns

A bound state:

• the parameters at the surface
• the stepwise jacobian towards it (from last bound)
• and the path length (from start - for ordering)

Definition at line 17 of file StraightLineStepper.cpp.

View newest version in sPHENIX GitHub at line 17 of file StraightLineStepper.cpp

References Acts::detail::boundState(), Acts::StraightLineStepper::State::cov, Acts::StraightLineStepper::State::covTransport, Acts::StraightLineStepper::State::derivative, Acts::StraightLineStepper::State::dir, Acts::eFreeDir0, Acts::eFreeDir1, Acts::eFreeDir2, Acts::eFreePos0, Acts::eFreePos1, Acts::eFreePos2, Acts::eFreeQOverP, Acts::eFreeTime, Acts::eMom0, Acts::eMom1, Acts::eMom2, Acts::ePos0, Acts::ePos1, Acts::ePos2, Acts::StraightLineStepper::State::geoContext, Acts::StraightLineStepper::State::jacobian, Acts::StraightLineStepper::State::jacToGlobal, Acts::StraightLineStepper::State::jacTransport, Acts::StraightLineStepper::State::p, Dataset::parameters, Acts::StraightLineStepper::State::pathAccumulated, Acts::StraightLineStepper::State::pos, Acts::StraightLineStepper::State::q, and Acts::StraightLineStepper::State::t.

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

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double Acts::StraightLineStepper::charge ( const State &  state ) const

inline

Charge access

Parameters

state

[in] The stepping state (thread-local cache)

Definition at line 184 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 184 of file StraightLineStepper.hpp

References Acts::StraightLineStepper::State::q.

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

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void Acts::StraightLineStepper::covarianceTransport

(

State &

state

)

const

Method for on-demand transport of the covariance to a new curvilinear frame at current position, or direction of the state - for the moment a dummy method

Parameters

[in,out]

state

State of the stepper

Definition at line 67 of file StraightLineStepper.cpp.

View newest version in sPHENIX GitHub at line 67 of file StraightLineStepper.cpp

References Acts::StraightLineStepper::State::cov, Acts::detail::covarianceTransport(), Acts::StraightLineStepper::State::derivative, Acts::StraightLineStepper::State::dir, Acts::StraightLineStepper::State::jacobian, Acts::StraightLineStepper::State::jacToGlobal, and Acts::StraightLineStepper::State::jacTransport.

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

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void Acts::StraightLineStepper::covarianceTransport	(	State &	state,
		const Surface &	surface
	)		const

Method for on-demand transport of the covariance to a new curvilinear frame at current position, or direction of the state - for the moment a dummy method

Template Parameters

surface_t

the surface type - ignored here

Parameters

[in,out]	state	The stepper state
[in]	surface	is the surface to which the covariance is forwarded to

Note

no check is done if the position is actually on the surface

Definition at line 72 of file StraightLineStepper.cpp.

View newest version in sPHENIX GitHub at line 72 of file StraightLineStepper.cpp

References Acts::StraightLineStepper::State::cov, Acts::detail::covarianceTransport(), Acts::StraightLineStepper::State::derivative, Acts::StraightLineStepper::State::dir, Acts::eFreeDir0, Acts::eFreeDir1, Acts::eFreeDir2, Acts::eFreePos0, Acts::eFreePos1, Acts::eFreePos2, Acts::eFreeQOverP, Acts::eFreeTime, Acts::eMom0, Acts::eMom1, Acts::eMom2, Acts::ePos0, Acts::ePos1, Acts::ePos2, Acts::StraightLineStepper::State::geoContext, Acts::StraightLineStepper::State::jacobian, Acts::StraightLineStepper::State::jacToGlobal, Acts::StraightLineStepper::State::jacTransport, Acts::StraightLineStepper::State::p, Dataset::parameters, Acts::StraightLineStepper::State::pos, Acts::StraightLineStepper::State::q, and Acts::StraightLineStepper::State::t.

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std::tuple< CurvilinearTrackParameters, BoundMatrix, double > Acts::StraightLineStepper::curvilinearState

(

State &

state

)

const

This creates a curvilinear state.

Create and return a curvilinear state at the current position

Parameters

[in]

state

State that will be presented as CurvilinearState

Returns

A curvilinear state:

• the curvilinear parameters at given position
• the stepweise jacobian towards it (from last bound)
• and the path length (from start - for ordering)

Definition at line 34 of file StraightLineStepper.cpp.

View newest version in sPHENIX GitHub at line 34 of file StraightLineStepper.cpp

References Acts::StraightLineStepper::State::cov, Acts::StraightLineStepper::State::covTransport, Acts::detail::curvilinearState(), Acts::StraightLineStepper::State::derivative, Acts::StraightLineStepper::State::dir, Acts::eFreeDir0, Acts::eFreeDir1, Acts::eFreeDir2, Acts::eFreePos0, Acts::eFreePos1, Acts::eFreePos2, Acts::eFreeQOverP, Acts::eFreeTime, Acts::eMom0, Acts::eMom1, Acts::eMom2, Acts::ePos0, Acts::ePos1, Acts::ePos2, Acts::StraightLineStepper::State::jacobian, Acts::StraightLineStepper::State::jacToGlobal, Acts::StraightLineStepper::State::jacTransport, Acts::StraightLineStepper::State::p, Dataset::parameters, Acts::StraightLineStepper::State::pathAccumulated, Acts::StraightLineStepper::State::pos, Acts::StraightLineStepper::State::q, and Acts::StraightLineStepper::State::t.

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

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Vector3D Acts::StraightLineStepper::direction ( const State &  state ) const

inline

Momentum direction accessor

Parameters

state

[in] The stepping state (thread-local cache)

Definition at line 174 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 174 of file StraightLineStepper.hpp

References Acts::StraightLineStepper::State::dir.

Referenced by Acts::Test::BOOST_AUTO_TEST_CASE(), and resetState().

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Vector3D Acts::StraightLineStepper::getField ( State &  , const Vector3D &    ) const

inline

Get the field for the stepping, this gives back a zero field

Parameters

[in,out]	state	is the propagation state associated with the track the magnetic field cell is used (and potentially updated)
[in]	pos	is the field position

Definition at line 161 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 161 of file StraightLineStepper.hpp

double Acts::StraightLineStepper::momentum ( const State &  state ) const

inline

Momentum accessor

Parameters

state

[in] The stepping state (thread-local cache)

Definition at line 179 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 179 of file StraightLineStepper.hpp

References Acts::StraightLineStepper::State::p.

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

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std::string Acts::StraightLineStepper::outputStepSize ( const State &  state ) const

inline

Output the Step Size - single component

Parameters

state

[in,out] The stepping state (thread-local cache)

Definition at line 250 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 250 of file StraightLineStepper.hpp

References Acts::StraightLineStepper::State::stepSize, and Acts::ConstrainedStep::toString().

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

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double Acts::StraightLineStepper::overstepLimit ( const State &  ) const

inline

Overstep limit

Parameters

state

The stepping state (thread-local cache)

Definition at line 194 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 194 of file StraightLineStepper.hpp

References Acts::s_onSurfaceTolerance.

Vector3D Acts::StraightLineStepper::position ( const State &  state ) const

inline

Global particle position accessor

Parameters

state

[in] The stepping state (thread-local cache)

Definition at line 169 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 169 of file StraightLineStepper.hpp

References Acts::StraightLineStepper::State::pos.

Referenced by Acts::Test::BOOST_AUTO_TEST_CASE(), and resetState().

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void Acts::StraightLineStepper::releaseStepSize ( State &  state ) const

inline

Release the Step size

Parameters

state

[in,out] The stepping state (thread-local cache)

Definition at line 243 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 243 of file StraightLineStepper.hpp

References Acts::ConstrainedStep::actor, Acts::ConstrainedStep::release(), and Acts::StraightLineStepper::State::stepSize.

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

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void Acts::StraightLineStepper::resetState	(	State &	state,
		const BoundVector &	boundParams,
		const BoundSymMatrix &	cov,
		const Surface &	surface,
		const NavigationDirection	navDir = forward,
		const double	stepSize = std::numeric_limits<double>::max()
	)		const

Resets the state.

Parameters

[in,out]	state	State of the stepper
[in]	boundParams	Parameters in bound parametrisation
[in]	freeParams	Parameters in free parametrisation
[in]	cov	Covariance matrix
[in]	navDir	Navigation direction
[in]	stepSize	Step size

Definition at line 88 of file StraightLineStepper.cpp.

View newest version in sPHENIX GitHub at line 88 of file StraightLineStepper.cpp

References Acts::StraightLineStepper::State::derivative, direction(), Acts::StraightLineStepper::State::geoContext, Acts::Surface::initJacobianToGlobal(), Acts::StraightLineStepper::State::jacobian, Acts::StraightLineStepper::State::jacToGlobal, Acts::StraightLineStepper::State::jacTransport, Acts::Test::navDir, Acts::StraightLineStepper::State::navDir, Acts::StraightLineStepper::State::pathAccumulated, position(), Acts::StraightLineStepper::State::stepSize, Acts::detail::transformBoundToFreeParameters(), and update().

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

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void Acts::StraightLineStepper::setStepSize ( State &  state, double  stepSize, ConstrainedStep::Type  stype = ConstrainedStep::actor  ) const

inline

Set Step size - explicitely with a double

Parameters

state	[in,out] The stepping state (thread-local cache)
stepSize	[in] The step size value
stype	[in] The step size type to be set

Definition at line 234 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 234 of file StraightLineStepper.hpp

References Acts::StraightLineStepper::State::previousStepSize, Acts::StraightLineStepper::State::stepSize, and Acts::ConstrainedStep::update().

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

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template<typename propagator_state_t >

Result<double> Acts::StraightLineStepper::step ( propagator_state_t &  state ) const

inline

Perform a straight line propagation step

Parameters

[in,out]

state

is the propagation state associated with the track parameters that are being propagated. The state contains the desired step size, it can be negative during backwards track propagation, and since we're using an adaptive algorithm, it can be modified by the stepper class during propagation.

Returns

the step size taken

Definition at line 328 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 328 of file StraightLineStepper.hpp

References Acts::UnitConstants::h.

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

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double Acts::StraightLineStepper::time ( const State &  state ) const

inline

Time access

Parameters

state

[in] The stepping state (thread-local cache)

Definition at line 189 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 189 of file StraightLineStepper.hpp

References Acts::StraightLineStepper::State::t.

Referenced by Acts::Test::BOOST_AUTO_TEST_CASE(), and update().

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void Acts::StraightLineStepper::update	(	State &	state,
		const FreeVector &	parameters,
		const Covariance &	covariance
	)		const

Method to update a stepper state to the some parameters

Parameters

[in,out]	state	State object that will be updated
[in]	pars	Parameters that will be written into state

Definition at line 49 of file StraightLineStepper.cpp.

View newest version in sPHENIX GitHub at line 49 of file StraightLineStepper.cpp

References kdfinder::abs(), Acts::StraightLineStepper::State::cov, Acts::StraightLineStepper::State::dir, Acts::eFreeDir0, Acts::eFreePos0, Acts::eFreeQOverP, Acts::eFreeTime, Acts::StraightLineStepper::State::p, Acts::StraightLineStepper::State::pos, and Acts::StraightLineStepper::State::t.

Referenced by Acts::Test::BOOST_AUTO_TEST_CASE(), and resetState().

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void Acts::StraightLineStepper::update	(	State &	state,
		const Vector3D &	uposition,
		const Vector3D &	udirection,
		double	up,
		double	time
	)		const

Method to update momentum, direction and p

Parameters

[in,out]	state	State object that will be updated
[in]	uposition	the updated position
[in]	udirection	the updated direction
[in]	up	the updated momentum value
[in]	time	the updated time value

Definition at line 58 of file StraightLineStepper.cpp.

View newest version in sPHENIX GitHub at line 58 of file StraightLineStepper.cpp

References Acts::StraightLineStepper::State::dir, Acts::StraightLineStepper::State::p, Acts::StraightLineStepper::State::pos, Acts::StraightLineStepper::State::t, and time().

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template<typename object_intersection_t >

void Acts::StraightLineStepper::updateStepSize ( State &  state, const object_intersection_t &  oIntersection, bool  release = true  ) const

inline

Update step size

It checks the status to the reference surface & updates the step size accordingly

Parameters

state	[in,out] The stepping state (thread-local cache)
oIntersection	[in] The ObjectIntersection to layer, boundary, etc
release	[in] boolean to trigger step size release

Definition at line 223 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 223 of file StraightLineStepper.hpp

References conf::release.

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

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Intersection3D::Status Acts::StraightLineStepper::updateSurfaceStatus ( State &  state, const Surface &  surface, const BoundaryCheck &  bcheck  ) const

inline

Update surface status

This method intersects the provided surface and update the navigation step estimation accordingly (hence it changes the state). It also returns the status of the intersection to trigger onSurface in case the surface is reached.

Parameters

state	[in,out] The stepping state (thread-local cache)
surface	[in] The surface provided
bcheck	[in] The boundary check for this status update

Definition at line 208 of file StraightLineStepper.hpp.

View newest version in sPHENIX GitHub at line 208 of file StraightLineStepper.hpp

References surface().

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

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---

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

• acts/blob/sPHENIX/Core/include/Acts/Propagator/StraightLineStepper.hpp
• acts/blob/sPHENIX/Core/src/Propagator/StraightLineStepper.cpp