This class performs the Ridders algorithm to estimate the propagation of the covariance to a certain point in space. More...

#include <acts/blob/master/Core/include/Acts/Propagator/RiddersPropagator.hpp>

Classes
struct	result_type_helper
	Helper struct determining the result's type. More...

Public Member Functions
	RiddersPropagator (propagator_t &propagator)
	Constructor using a propagator.

template<typename stepper_t , typename navigator_t = detail::VoidNavigator>
	RiddersPropagator (stepper_t stepper, navigator_t navigator=navigator_t())
	Constructor building a propagator.

template<typename parameters_t , typename propagator_options_t >
Result< action_list_t_result_t < CurvilinearParameters, typename propagator_options_t::action_list_type > >	propagate (const parameters_t &start, const propagator_options_t &options) const
	Propagation method targeting curvilinear parameters.

template<typename parameters_t , typename propagator_options_t >
Result< action_list_t_result_t < BoundParameters, typename propagator_options_t::action_list_type > >	propagate (const parameters_t &start, const Surface &target, const propagator_options_t &options) const
	Propagation method targeting bound parameters.

Private Types
using	Jacobian = BoundMatrix

using	Covariance = BoundSymMatrix

template<typename parameters_t , typename action_list_t >
using	action_list_t_result_t = typename result_type_helper< parameters_t, action_list_t >::type
	Short-hand type definition for propagation result derived from an action list.

Private Member Functions
bool	inconsistentDerivativesOnDisc (const std::vector< BoundVector > &derivatives) const
	This function tests whether the variations on a disc as target surface lead to results on different sides wrt the center of the disc. This would lead to a flip of the phi value on the surface and therewith to a huge variance in that parameter. It can only occur in this algorithm since the ridders algorithm is unaware of the target surface.

template<typename options_t , typename parameters_t >
std::vector< BoundVector >	wiggleDimension (const options_t &options, const parameters_t &startPars, const unsigned int param, const Surface &target, const BoundVector &nominal, const std::vector< double > &deviations) const
	This function wiggles one dimension of the starting parameters, performs the propagation to a surface and collects for each change of the start parameters the slope.

const Covariance	calculateCovariance (const std::array< std::vector< BoundVector >, eBoundParametersSize > &derivatives, const Covariance &startCov, const std::vector< double > &deviations) const
	This function propagates the covariance matrix.

BoundVector	fitLinear (const std::vector< BoundVector > &values, const std::vector< double > &deviations) const
	This function fits a linear function through the final state parametrisations.

Private Attributes
propagator_t	m_propagator
	Propagator.

Detailed Description

template<typename propagator_t>
class Acts::RiddersPropagator< propagator_t >

This class performs the Ridders algorithm to estimate the propagation of the covariance to a certain point in space.

The algorithm is based on the small deviations of the start parameters based on their uncertainty at the beginning of the propgation. This deviation is represented here by a vector of relative deviations of these parameters and fix for all parameters. So, a common choice has to be found that is able to actually fit into the order of magnitude of the uncertainty of each parameter. Using these deviations, the propagation is repeated multiple times and the final covariance matrix at a given target surface is afterwards evaluated by first order derivatives of the final state parameters wrt. the inital parameters. Therefore this evaluation represents a first order approximation of the transport jacobian. Since performing multiple propagations and a numerical evaluation of the covariance requires more time than a single propagation towards a target + a common propagation of the covariance, this class just serves to verify the results of the latter classes.

Definition at line 34 of file RiddersPropagator.hpp.

View newest version in sPHENIX GitHub at line 34 of file RiddersPropagator.hpp

Member Typedef Documentation

template<typename propagator_t >

template<typename parameters_t , typename action_list_t >

using Acts::RiddersPropagator< propagator_t >::action_list_t_result_t = typename result_type_helper<parameters_t, action_list_t>::type

private

Short-hand type definition for propagation result derived from an action list.

Template Parameters

parameters_t	Type of the final track parameters
action_list_t	List of propagation action types

Definition at line 58 of file RiddersPropagator.hpp.

View newest version in sPHENIX GitHub at line 58 of file RiddersPropagator.hpp

template<typename propagator_t >

using Acts::RiddersPropagator< propagator_t >::Covariance = BoundSymMatrix

private

Definition at line 36 of file RiddersPropagator.hpp.

View newest version in sPHENIX GitHub at line 36 of file RiddersPropagator.hpp

template<typename propagator_t >

using Acts::RiddersPropagator< propagator_t >::Jacobian = BoundMatrix

private

Definition at line 35 of file RiddersPropagator.hpp.

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

Constructor & Destructor Documentation

template<typename propagator_t >

Acts::RiddersPropagator< propagator_t >::RiddersPropagator ( propagator_t & propagator )

inline

Constructor using a propagator.

Parameters

[in] propagator Underlying propagator that will be used

Definition at line 64 of file RiddersPropagator.hpp.

View newest version in sPHENIX GitHub at line 64 of file RiddersPropagator.hpp

template<typename propagator_t >

template<typename stepper_t , typename navigator_t = detail::VoidNavigator>

Acts::RiddersPropagator< propagator_t >::RiddersPropagator	(	stepper_t	stepper,
		navigator_t	navigator = `navigator_t()`
	)

inline

Constructor building a propagator.

Template Parameters

stepper_t	Type of the stepper
navigator_t	Type of the navigator

Parameters

[in]	stepper	Stepper that will be used
[in]	navigator	Navigator that will be used

Definition at line 74 of file RiddersPropagator.hpp.

View newest version in sPHENIX GitHub at line 74 of file RiddersPropagator.hpp

Member Function Documentation

template<typename propagator_t >

auto Acts::RiddersPropagator< propagator_t >::calculateCovariance	(	const std::array< std::vector< BoundVector >, eBoundParametersSize > &	derivatives,
		const Covariance &	startCov,
		const std::vector< double > &	deviations
	)		const

private

This function propagates the covariance matrix.

Parameters

[in]	derivatives	Slopes of each modification of the parameters
[in]	startCov	Starting covariance

Returns: Propagated covariance matrix

Definition at line 210 of file RiddersPropagator.ipp.

View newest version in sPHENIX GitHub at line 210 of file RiddersPropagator.ipp

References Acts::eLOC_0, Acts::eLOC_1, Acts::ePHI, Acts::eQOP, Acts::eT, and Acts::eTHETA.

template<typename propagator_t >

Acts::BoundVector Acts::RiddersPropagator< propagator_t >::fitLinear	(	const std::vector< BoundVector > &	values,
		const std::vector< double > &	deviations
	)		const

private

This function fits a linear function through the final state parametrisations.

Parameters

[in] values Vector containing the final state parametrisations

Returns: Vector containing the linear fit

Definition at line 227 of file RiddersPropagator.ipp.

View newest version in sPHENIX GitHub at line 227 of file RiddersPropagator.ipp

References a, A(), b, B(), C(), D(), and N.

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template<typename propagator_t >

bool Acts::RiddersPropagator< propagator_t >::inconsistentDerivativesOnDisc ( const std::vector< BoundVector > & derivatives ) const

private

This function tests whether the variations on a disc as target surface lead to results on different sides wrt the center of the disc. This would lead to a flip of the phi value on the surface and therewith to a huge variance in that parameter. It can only occur in this algorithm since the ridders algorithm is unaware of the target surface.

Parameters

[in] derivatives Derivatives of a single parameter

Returns: Boolean result whether a phi jump occured

Definition at line 113 of file RiddersPropagator.ipp.

View newest version in sPHENIX GitHub at line 113 of file RiddersPropagator.ipp

References kdfinder::abs(), and M_PI.

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template<typename propagator_t >

template<typename parameters_t , typename propagator_options_t >

auto Acts::RiddersPropagator< propagator_t >::propagate	(	const parameters_t &	start,
		const propagator_options_t &	options
	)		const

Propagation method targeting curvilinear parameters.

Template Parameters

parameters_t	Type of the start parameters
propagator_options_t	Type of the propagator options

Parameters

[in]	start	Start parameters
[in]	options	Options of the propagations

Returns: Result of the propagation

Definition at line 11 of file RiddersPropagator.ipp.

View newest version in sPHENIX GitHub at line 11 of file RiddersPropagator.ipp

References e, Acts::eBoundParametersSize, start(), and surface().

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template<typename propagator_t >

template<typename parameters_t , typename propagator_options_t >

auto Acts::RiddersPropagator< propagator_t >::propagate	(	const parameters_t &	start,
		const Surface &	target,
		const propagator_options_t &	options
	)		const

Propagation method targeting bound parameters.

Template Parameters

parameters_t	Type of the start parameters
propagator_options_t	Type of the propagator options

Parameters

[in]	start	Start parameters
[in]	options	Options of the propagations

Returns: Result of the propagation

Note: If the target surface is a disc, the resulting covariance may be inconsistent. In this case a zero matrix is returned.

Definition at line 52 of file RiddersPropagator.ipp.

View newest version in sPHENIX GitHub at line 52 of file RiddersPropagator.ipp

References deriv(), e, Acts::eBoundParametersSize, Acts::SingleTrackParameters< ChargePolicy >::parameters(), and start().

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template<typename propagator_t >

template<typename options_t , typename parameters_t >

std::vector< Acts::BoundVector > Acts::RiddersPropagator< propagator_t >::wiggleDimension	(	const options_t &	options,
		const parameters_t &	startPars,
		const unsigned int	param,
		const Surface &	target,
		const BoundVector &	nominal,
		const std::vector< double > &	deviations
	)		const

private

This function wiggles one dimension of the starting parameters, performs the propagation to a surface and collects for each change of the start parameters the slope.

Template Parameters

options_t	PropagatorOptions object
parameters+t	Type of the parameters to start the propagation with

Parameters

[in]	options	Options do define how to wiggle
[in]	startPart	Start parameters that are modified
[in]	param	Index to get the parameter that will be modified
[in]	target	Target surface
[in]	nominal	Nominal end parameters

Returns: Vector containing each slope

Definition at line 138 of file RiddersPropagator.ipp.

View newest version in sPHENIX GitHub at line 138 of file RiddersPropagator.ipp

References kdfinder::abs(), Acts::ePHI, Acts::eTHETA, Acts::UnitConstants::h, M_PI, r, and G4InuclParticleNames::tp.

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Member Data Documentation

template<typename propagator_t >

propagator_t Acts::RiddersPropagator< propagator_t >::m_propagator

private

Propagator.

Definition at line 163 of file RiddersPropagator.hpp.

View newest version in sPHENIX GitHub at line 163 of file RiddersPropagator.hpp

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

acts/blob/master/Core/include/Acts/Propagator/RiddersPropagator.hpp
acts/blob/master/Core/include/Acts/Propagator/RiddersPropagator.ipp

Classes

Public Member Functions

Private Types

Private Member Functions

Private Attributes

Detailed Description

template<typename propagator_t> class Acts::RiddersPropagator< propagator_t >

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

template<typename propagator_t>
class Acts::RiddersPropagator< propagator_t >