#include <Acts/Utilities/SpacePointUtility.hpp>

Public Member Functions
	SpacePointUtility (SpacePointBuilderConfig cfg)
	Constructor.
Result< double >	calcPerpendicularProjection (const std::pair< Vector3, Vector3 > &stripEnds1, const std::pair< Vector3, Vector3 > &stripEnds2, SpacePointParameters &spParams) const
	Calculates a space point without using the vertex.
Vector2	calcRhoZVars (const GeometryContext &gctx, const SourceLink &slinkFront, const SourceLink &slinkBack, const SourceLinkSurfaceAccessor &surfaceAccessor, const ParamCovAccessor &paramCovAccessor, const Vector3 &globalPos, const double theta) const
	Calculate the rho and z covariance from the front and back SourceLink in the strip SP formation.
Result< void >	calculateStripSPPosition (const std::pair< Vector3, Vector3 > &stripEnds1, const std::pair< Vector3, Vector3 > &stripEnds2, const Vector3 &posVertex, SpacePointParameters &spParams, const double stripLengthTolerance) const
	This function performs a straight forward calculation of a space point and returns whether it was successful or not.
Result< double >	differenceOfMeasurementsChecked (const Vector3 &pos1, const Vector3 &pos2, const Vector3 &posVertex, const double maxDistance, const double maxAngleTheta2, const double maxAnglePhi2) const
	Calculates (Delta theta)^2 + (Delta phi)^2 between two SourceLinks.
std::tuple< Vector3, std::optional< double >, Vector2, std::optional< double > >	globalCoords (const GeometryContext &gctx, const SourceLink &slink, const SourceLinkSurfaceAccessor &surfaceAccessor, const BoundVector &par, const BoundSquareMatrix &cov) const
	Getter method for the global coordinates of a SourceLink.
Result< void >	recoverSpacePoint (SpacePointParameters &spParams, double stripLengthGapTolerance) const
	This function tests if a space point can be estimated by a more tolerant treatment of construction.
Vector2	rhoZCovariance (const GeometryContext &gctx, const Surface &surface, const Vector3 &globalPos, const SquareMatrix2 &localCov) const
	Get rho and z covariance from the local position and covariance.

Constructor & Destructor Documentation

◆ SpacePointUtility()

Acts::SpacePointUtility::SpacePointUtility ( SpacePointBuilderConfig cfg )

explicit

Constructor.

Member Function Documentation

◆ calcPerpendicularProjection()

Result< double > Acts::SpacePointUtility::calcPerpendicularProjection	(	const std::pair< Vector3, Vector3 > &	stripEnds1,
		const std::pair< Vector3, Vector3 > &	stripEnds2,
		SpacePointParameters &	spParams ) const

Calculates a space point without using the vertex.

Note: This is mostly to resolve space points from cosmic data

Parameters

stripEnds1	The ends of one strip
stripEnds2	The ends of another strip
spParams	SpacePointParamaters for the SP

Returns

parameter that indicates the location of the space point; returns

if it failed

Note: The meaning of the parameter is explained in more detail in the function body

◆ calcRhoZVars()

Vector2 Acts::SpacePointUtility::calcRhoZVars	(	const GeometryContext &	gctx,
		const SourceLink &	slinkFront,
		const SourceLink &	slinkBack,
		const SourceLinkSurfaceAccessor &	surfaceAccessor,
		const ParamCovAccessor &	paramCovAccessor,
		const Vector3 &	globalPos,
		const double	theta ) const

Calculate the rho and z covariance from the front and back SourceLink in the strip SP formation.

Parameters

gctx	The current geometry context object, e.g. alignment
slinkFront	The SourceLink on the front layer
slinkBack	The SourceLink on the back layer
paramCovAccessor	function to extract local position and covariance from SourceLink
surfaceAccessor	function to extract surface from SourceLink
globalPos	global position
theta	The angle between the two strips

Returns: (rho, z) components of the global covariance

◆ calculateStripSPPosition()

Result< void > Acts::SpacePointUtility::calculateStripSPPosition	(	const std::pair< Vector3, Vector3 > &	stripEnds1,
		const std::pair< Vector3, Vector3 > &	stripEnds2,
		const Vector3 &	posVertex,
		SpacePointParameters &	spParams,
		const double	stripLengthTolerance ) const

This function performs a straight forward calculation of a space point and returns whether it was successful or not.

Parameters

[in]	stripEnds1	Top and bottom end of the first strip
[in]	stripEnds2	Top and bottom end of the second strip
[in]	posVertex	Position of the vertex
[in,out]	spParams	Data container of the calculations
[in]	stripLengthTolerance	Tolerance scaling factor on the strip detector element length

Returns: Result whether the space point calculation was successful

◆ differenceOfMeasurementsChecked()

Result< double > Acts::SpacePointUtility::differenceOfMeasurementsChecked	(	const Vector3 &	pos1,
		const Vector3 &	pos2,
		const Vector3 &	posVertex,
		const double	maxDistance,
		const double	maxAngleTheta2,
		const double	maxAnglePhi2 ) const

Calculates (Delta theta)^2 + (Delta phi)^2 between two SourceLinks.

Parameters

[in]	pos1	position of the first SourceLink
[in]	pos2	position the second SourceLink
[in]	posVertex	Position of the vertex
[in]	maxDistance	Maximum distance between two SourceLinks
[in]	maxAngleTheta2	Maximum squared theta angle between two SourceLinks
[in]	maxAnglePhi2	Maximum squared phi angle between two SourceLinks

Returns: Result with the squared sum within configuration parameters.

◆ globalCoords()

std::tuple< Vector3, std::optional< double >, Vector2, std::optional< double > > Acts::SpacePointUtility::globalCoords	(	const GeometryContext &	gctx,
		const SourceLink &	slink,
		const SourceLinkSurfaceAccessor &	surfaceAccessor,
		const BoundVector &	par,
		const BoundSquareMatrix &	cov ) const

Getter method for the global coordinates of a SourceLink.

Parameters

gctx	The current geometry context object, e.g. alignment
slink	SourceLink that holds the necessary information
surfaceAccessor	function to extract surface from SourceLink
par	local position
cov	local covariance

Returns: vectors of the global coordinates and covariance of the SourceLink

◆ recoverSpacePoint()

Result< void > Acts::SpacePointUtility::recoverSpacePoint	(	SpacePointParameters &	spParams,
		double	stripLengthGapTolerance ) const

This function tests if a space point can be estimated by a more tolerant treatment of construction.

In fact, this function indirectly allows shifts of the vertex.

Parameters

[in]	spParams	container that stores geometric parameters and rules of the space point formation
[in]	stripLengthGapTolerance	Tolerance scaling factor of the gap between strip detector elements

Returns: indicator if the test was successful

◆ rhoZCovariance()

Vector2 Acts::SpacePointUtility::rhoZCovariance	(	const GeometryContext &	gctx,
		const Surface &	surface,
		const Vector3 &	globalPos,
		const SquareMatrix2 &	localCov ) const

Get rho and z covariance from the local position and covariance.

Parameters

gctx	The current geometry context object, e.g. alignment
surface	The surface associated
globalPos	The global position
localCov	The local covariance matrix

Returns: (rho, z) components of the global covariance

Public Member Functions

Constructor & Destructor Documentation

◆ SpacePointUtility()

Member Function Documentation

◆ calcPerpendicularProjection()

◆ calcRhoZVars()

◆ calculateStripSPPosition()

◆ differenceOfMeasurementsChecked()

◆ globalCoords()

◆ recoverSpacePoint()

◆ rhoZCovariance()