Acts::HelixStepper::State Struct Reference

State for track parameter propagation. More...

#include <Acts/Propagator/HelixStepper.hpp>

Collaboration diagram for Acts::HelixStepper::State:

Public Member Functions
	State (const Options &optionsIn, MagneticFieldProvider::Cache fieldCacheIn)
	Constructor from the options and the field cache.

Public Attributes
std::optional< Covariance >	cov
	Covariance matrix for track parameter uncertainties, set if the covariance is transported.
FreeVector	derivative = FreeVector::Zero()
	The propagation derivative.
std::optional< Vector3 >	field
	Magnetic field at the current position, reused as the next step's field.
MagneticFieldProvider::Cache	fieldCache
	This caches the current magnetic field cell and stays (and interpolates) within it as long as this is valid.
BoundToFreeMatrix	jacToGlobal = BoundToFreeMatrix::Zero()
	Jacobian from local to the global frame.
FreeMatrix	jacTransport = FreeMatrix::Identity()
	Pure transport jacobian part from the helix steps.
std::size_t	nSteps = 0
	Total number of performed steps.
Options	options
	Configuration options for the stepper.
FreeVector	pars = FreeVector::Zero()
	Internal free vector parameters.
ParticleHypothesis	particleHypothesis = ParticleHypothesis::pion()
	Particle hypothesis.
double	pathAccumulated = 0.
	Accumulated path length state.
double	previousStepSize = 0.
	Last performed step (for overstep limit calculation).
StepperStatistics	statistics
	Statistics of the stepper.
ConstrainedStep	stepSize
	Adaptive step size of the helix steps.

Detailed Description

State for track parameter propagation.

It contains the stepping information and is provided thread local by the propagator

Constructor & Destructor Documentation

State()

Acts::HelixStepper::State::State	(	const Options &	optionsIn,
		MagneticFieldProvider::Cache	fieldCacheIn )

Constructor from the options and the field cache.

Parameters

[in]	optionsIn	is the configuration of the stepper
[in]	fieldCacheIn	is the cache object for the magnetic field

Member Data Documentation

field

std::optional<Vector3> Acts::HelixStepper::State::field

Magnetic field at the current position, reused as the next step's field.

Reset whenever the position is set from outside.