MuonR4::FastReco::GlobalPatternFinder::HitPayload Struct Reference

Base class for hit struct containing hit information. More...

#include <GlobalPatternFinderDefs.h>

Collaboration diagram for MuonR4::FastReco::GlobalPatternFinder::HitPayload:

Public Member Functions
	HitPayload (const Acts::GeometryContext &gctx, const SpacePoint *sp, const SpacePointBucket *bucket, const Amg::Transform3D &localToGlobal)
	Constructor with parameters.
Amg::Vector3D	sensorDir (const Acts::GeometryContext &gctx) const
	Sensor direction.
double	residualVariance (const Acts::GeometryContext &gctx, const Amg::Vector3D &contractionVector, const bool isProjected) const
	Hit contribution contribution to the residual variance due to its intrinsic position uncertainty.
bool	operator== (const HitPayload &other) const
	Equal operator: it compares the underlying hit.
const SpacePoint *	operator-> () const
	Arrow operator: it allows to access the underlying hit.
const SpacePoint &	operator* () const
	Dereference operator: it allows to access the underlying hit.

Public Attributes
Amg::Vector3D	position {Amg::Vector3D::Zero()}
	Global position.
const SpacePoint *	spacePoint {nullptr}
	Pointer to the underlying hit.
const SpacePointBucket *	bucket {nullptr}
	Pointer to the parent bucket.
double	phiCov {0.}
	Cached angular covariance [rad^2] of the hit in the phi angle.
double	stripAngle {0.}
	Strip angle when the strips are non-orthogonal.
StIndex	station {toStationIndex(spacePoint->msSector()->chamberIndex())}
	Station index.
uint8_t	locLayer {static_cast<uint8_t>(s_spSorter.sectorLayerNum(*spacePoint))}
	Layer number in the sector frame.
bool	isPrecision {isPrecisionHit(*spacePoint)}
	Is precision hit.
bool	nonOrthogonalStrips {false}
	Are the strips non-orthogonal.

Detailed Description

Base class for hit struct containing hit information.

Definition at line 19 of file GlobalPatternFinderDefs.h.

Constructor & Destructor Documentation

HitPayload()

MuonR4::FastReco::GlobalPatternFinder::HitPayload::HitPayload ( const Acts::GeometryContext & gctx, const SpacePoint * sp, const SpacePointBucket * bucket, const Amg::Transform3D & localToGlobal )

explicit

Constructor with parameters.

Parameters

sp	The space point
bucket	The space point bucket
localToGlobal	The transformation from local to global coordinates
locLayer	The layer number in the sector frame
station	The station index

Helper method to compute the contribution of a 1D measurement to the residual variance

Definition at line 32 of file GlobalPatternFinderDefs.cxx.

        : position{localToGlobal * sp->localPosition()}, 
          spacePoint{sp}, bucket{bucket} {
 
        using CovIdx = SpacePoint::CovIdx;
        
        if (!sp->measuresEta()) {
            // Phi-only measurements
            const Amg::Vector3D phiMeasDir {localToGlobal.rotation() * sp->toNextSensor()};
 
            phiCov = sp->covariance()[Acts::toUnderlying(CovIdx::phiCov)] *
                Acts::square(phiMeasDir.dot(phiGradient(position)));
            return;
        }
        const auto& surfLinearTrf = xAOD::muonSurface(sp->primaryMeasurement()).localToGlobalTransform(gctx).linear();
        
        if (sp->isStraw()) {
            // Remember that for straw hits, the x component of secondaryMeasDir is repurposed 
            // to store the transverse covariance of the drift radius
            double& discCov = stripAngle; 
            discCov = Acts::square(sp->driftRadius()) +
                sp->covariance()[Acts::toUnderlying(CovIdx::etaCov)];
            
            if (sp->measuresPhi()) {
                phiCov = discCov / Acts::square(position.perp()) +
                    Acts::square(sensorDir(gctx).dot(phiGradient(position))) * 
                        (sp->covariance()[Acts::toUnderlying(CovIdx::phiCov)] - discCov);
            }
        } else if (sp->measuresPhi()) {
            const Amg::Vector3D phiMeasDir = surfLinearTrf.col(Amg::y);
            const Amg::Vector3D gradPhi {phiGradient(position)};
            auto oneDimContribution = [&](CovIdx idx, const Amg::Vector3D& measDir) -> double {
                return sp->covariance()[Acts::toUnderlying(idx)] * 
                    Acts::square(measDir.dot(gradPhi));
            };
            
            // Handle the case of TGC separately
            if (sp->type() == xAOD::UncalibMeasType::TgcStripType) {
                const Amg::Vector3D etaMeasDir = localToGlobal.rotation() * sp->toNextSensor();
                const Amg::Vector3D phiSensorDir = surfLinearTrf.col(Amg::x);
                
                const double c {etaMeasDir.dot(phiMeasDir)};
                if (std::abs(c) > Acts::s_epsilon) {
                    stripAngle = std::atan2(etaMeasDir.dot(phiSensorDir), c);
                    nonOrthogonalStrips = true;
                }
                phiCov = oneDimContribution(CovIdx::etaCov, etaMeasDir) +
                         oneDimContribution(CovIdx::phiCov, phiMeasDir);
            } else {
                const Amg::Vector3D etaMeasDir = surfLinearTrf.col(Amg::x);
                phiCov = oneDimContribution(CovIdx::etaCov, etaMeasDir) +
                         oneDimContribution(CovIdx::phiCov, phiMeasDir);
            }
        }
    }

Member Function Documentation

operator*()

const SpacePoint & MuonR4::FastReco::GlobalPatternFinder::HitPayload::operator* ( ) const

inline

Dereference operator: it allows to access the underlying hit.

Definition at line 65 of file GlobalPatternFinderDefs.h.

{ return *spacePoint; }

operator->()

const SpacePoint * MuonR4::FastReco::GlobalPatternFinder::HitPayload::operator-> ( ) const

inline

Arrow operator: it allows to access the underlying hit.

Definition at line 63 of file GlobalPatternFinderDefs.h.

{ return spacePoint; }

operator==()

bool MuonR4::FastReco::GlobalPatternFinder::HitPayload::operator==

(

const HitPayload &

other

)

const

Equal operator: it compares the underlying hit.

Definition at line 148 of file GlobalPatternFinderDefs.cxx.

                                                                              {
        return spacePoint == other.spacePoint;
    }

residualVariance()

double MuonR4::FastReco::GlobalPatternFinder::HitPayload::residualVariance	(	const Acts::GeometryContext &	gctx,
		const Amg::Vector3D &	contractionVector,
		const bool	isProjected ) const

Hit contribution contribution to the residual variance due to its intrinsic position uncertainty.

Parameters

contractionVector	The contraction vector to compute the residual variance
isProjected	Whether the hit has been projected

Returns

Residual variance contribution

If the hit is not projected, the contraction vector is the residual direction

If the hit is projected, the contraction vector is J^T * residualDirection, where J is the Jacobian of the projection. The phi measurement if available is cancelled by the projection.

Helper method to compute the contribution of a 1D measurement to the residual variance

Definition at line 106 of file GlobalPatternFinderDefs.cxx.

                                                                                    {
        using CovIdx = SpacePoint::CovIdx;

        assert(isProjected || std::abs(contractionVector.mag() - 1.0) < Acts::s_epsilon);
        
        if (spacePoint->isStraw()) {
            const double discCov {stripAngle};
            if (!isProjected) {
                assert(sp->measuresPhi());
                const double vDotRsq {Acts::square(sensorDir(gctx).dot(contractionVector))};
                return discCov * (1 - vDotRsq) + 
                       vDotRsq * spacePoint->covariance()[Acts::toUnderlying(CovIdx::phiCov)];
            }
            return discCov * contractionVector.mag2();
 
        } else if (spacePoint->measuresEta()) {
            const auto& surfLinearTrf = xAOD::muonSurface(spacePoint->primaryMeasurement()).localToGlobalTransform(gctx).linear();
            auto oneDimContribution = [&](CovIdx idx, const Amg::Vector3D& measDir) -> double {
                return spacePoint->covariance()[Acts::toUnderlying(idx)] * 
                    Acts::square(measDir.dot(contractionVector));
            };
            if (spacePoint->measuresPhi()) {
                const Amg::Vector3D etaMeasDir {nonOrthogonalStrips 
                    ? sensorDir(gctx).cross(surfLinearTrf.col(Amg::z))
                    : surfLinearTrf.col(Amg::x)};
                const Amg::Vector3D phiMeasDir {surfLinearTrf.col(Amg::y)};
                return oneDimContribution(CovIdx::etaCov, etaMeasDir) + 
                       oneDimContribution(CovIdx::phiCov, phiMeasDir);
            }
            const Amg::Vector3D etaMeasDir {surfLinearTrf.col(Amg::x)};
            return oneDimContribution(CovIdx::etaCov, etaMeasDir);
        } else {
            throw std::runtime_error("Phi only hits are not meant to be used for residual computation.");
        }
    }

sensorDir()

Amg::Vector3D MuonR4::FastReco::GlobalPatternFinder::HitPayload::sensorDir

(

const Acts::GeometryContext &

gctx

)

const

Sensor direction.

Definition at line 91 of file GlobalPatternFinderDefs.cxx.

                                                                                              {
        const auto& surfLinearTrf = 
            xAOD::muonSurface(spacePoint->primaryMeasurement()).localToGlobalTransform(gctx).linear();
        
        if (spacePoint->isStraw()) {
            return surfLinearTrf.col(Amg::z);
        } else {
            if (nonOrthogonalStrips) {
                return - std::sin(stripAngle) * surfLinearTrf.col(Amg::y)
                       + std::cos(stripAngle) * surfLinearTrf.col(Amg::x);
            }
            return surfLinearTrf.col(Amg::y);
        }
    }

Member Data Documentation

bucket

const SpacePointBucket* MuonR4::FastReco::GlobalPatternFinder::HitPayload::bucket {nullptr}

Pointer to the parent bucket.

Definition at line 47 of file GlobalPatternFinderDefs.h.

{nullptr};

isPrecision

bool MuonR4::FastReco::GlobalPatternFinder::HitPayload::isPrecision {isPrecisionHit(*spacePoint)}

Is precision hit.

Definition at line 57 of file GlobalPatternFinderDefs.h.

{isPrecisionHit(*spacePoint)};

locLayer

uint8_t MuonR4::FastReco::GlobalPatternFinder::HitPayload::locLayer {static_cast<uint8_t>(s_spSorter.sectorLayerNum(*spacePoint))}

Layer number in the sector frame.

Definition at line 55 of file GlobalPatternFinderDefs.h.

{static_cast<uint8_t>(s_spSorter.sectorLayerNum(*spacePoint))};

nonOrthogonalStrips

bool MuonR4::FastReco::GlobalPatternFinder::HitPayload::nonOrthogonalStrips {false}

Are the strips non-orthogonal.

Definition at line 59 of file GlobalPatternFinderDefs.h.

{false};

phiCov

double MuonR4::FastReco::GlobalPatternFinder::HitPayload::phiCov {0.}

Cached angular covariance [rad^2] of the hit in the phi angle.

Definition at line 49 of file GlobalPatternFinderDefs.h.

{0.};

position

Amg::Vector3D MuonR4::FastReco::GlobalPatternFinder::HitPayload::position {Amg::Vector3D::Zero()}

Global position.

Definition at line 43 of file GlobalPatternFinderDefs.h.

{Amg::Vector3D::Zero()};

spacePoint

const SpacePoint* MuonR4::FastReco::GlobalPatternFinder::HitPayload::spacePoint {nullptr}

Pointer to the underlying hit.

Definition at line 45 of file GlobalPatternFinderDefs.h.

{nullptr};

station

StIndex MuonR4::FastReco::GlobalPatternFinder::HitPayload::station {toStationIndex(spacePoint->msSector()->chamberIndex())}

Station index.

Definition at line 53 of file GlobalPatternFinderDefs.h.

{toStationIndex(spacePoint->msSector()->chamberIndex())};

stripAngle

double MuonR4::FastReco::GlobalPatternFinder::HitPayload::stripAngle {0.}

Strip angle when the strips are non-orthogonal.

Definition at line 51 of file GlobalPatternFinderDefs.h.

{0.};

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

• GlobalPatternFinderDefs.h
• GlobalPatternFinderDefs.cxx