MuonR4::TruthTrackSeederTool Class Reference

The TruthTrackSeederTool combines the Segments based on their common truthParticleLink. More...

#include <TruthTrackSeederTool.h>

Inheritance diagram for MuonR4::TruthTrackSeederTool:

Collaboration diagram for MuonR4::TruthTrackSeederTool:

Public Member Functions
virtual StatusCode	initialize () override final
virtual StatusCode	findTrackSeeds (const EventContext &ctx, std::vector< MsTrackSeed > &outSeeds) const override final
	Retrieves the segment container from StoreGate and constructs TrackSeeds from them.
virtual Acts::Result< Acts::BoundTrackParameters >	estimateStartParameters (const EventContext &ctx, const MsTrackSeed &seed) const override final
	Estimate the start track parameters for a given track seed.

Private Attributes
SG::ReadHandleKey< xAOD::MuonSegmentContainer >	m_segmentKey {this, "SegmentContainer", "MuonSegmentsFromR4" }
	Declare the data dependency on the standard Mdt+Rpc+Tgc segment container & on the NSW segment container.
SG::ReadDecorHandleKey< xAOD::MuonSegmentContainer >	m_truthLinkKey {this, "TruthLinkKey", m_segmentKey, "truthParticleLink"}
	Dependency on the truth particle link.
MuonGMR4::MuonDetectorManager *	m_detMgr {nullptr}
	Instance to the muon detector manager.
ActsTrk::ContextUtility	m_ctxProvider {this}
	Context utility to retrieve the geometry context.

Detailed Description

The TruthTrackSeederTool combines the Segments based on their common truthParticleLink.

If multiple segments in the same chamber share the truthParticle, then the one which has the most amount of hits is chosen The initial track parameters are predicted from the closest truth segment along the trajectory. The tool only works on MC and is also entirely meant to evaluate the performance of the global chi2 fitter.

Definition at line 28 of file TruthTrackSeederTool.h.

Member Function Documentation

estimateStartParameters()

Acts::Result< Acts::BoundTrackParameters > MuonR4::TruthTrackSeederTool::estimateStartParameters ( const EventContext & ctx, const MsTrackSeed & seed ) const

finaloverridevirtual

Estimate the start track parameters for a given track seed.

Parameters

ctx	EventContext
seed	The track seed for which to estimate start parameters

Returns

The estimated start parameters or an error

Get the first two segments

Definition at line 77 of file TruthTrackSeederTool.cxx.

                                                                                     {
 
        const Acts::GeometryContext tgContext{m_ctxProvider.getGeometryContext(ctx)};
        const xAOD::MuonSegment* firstSeg = seed.segments().front();
        const xAOD::MuonSegment* secondSeg = seed.segments()[1];
        // If both segments are on the same station (BI) check whether the order needs to be swapped
        if (Muon::MuonStationIndex::toStationIndex(firstSeg->chamberIndex()) ==
            Muon::MuonStationIndex::toStationIndex(secondSeg->chamberIndex())) {
            const xAOD::MuonSegment* truthSeg = getMatchedTruthSegment(*firstSeg);
            if (!truthSeg) {
                ATH_MSG_WARNING(__func__<<"() "<<__LINE__<<" - No truth segment found");
                return Acts::Result<Acts::BoundTrackParameters>::failure(std::make_error_code(std::errc::invalid_argument));
            }
            const Acts::Surface& firstSurf{xAOD::muonSurface(firstMeasurement(*firstSeg, false))};
            const Acts::Surface& secondSurf{xAOD::muonSurface(firstMeasurement(*secondSeg, false))}; 
            const double distA = firstSurf.intersect(tgContext, truthSeg->position(), truthSeg->direction()).closest().pathLength();
            const double distB = secondSurf.intersect(tgContext, truthSeg->position(), truthSeg->direction()).closest().pathLength();
            ATH_MSG_VERBOSE(__func__<<" "<<__LINE__<<" - Detected segments in sector overlap "
                    <<printID(*firstSeg)<<" & "<<printID(*secondSeg)
                    <<". Check whether they need  to be swapped "<<distA<<" vs. "<<distB);
            if (distA> distB) {
                std::swap(firstSeg, secondSeg);
            }
        }
        const xAOD::MuonSegment* truthSeg = getMatchedTruthSegment(*firstSeg);
        if (!truthSeg) {
            ATH_MSG_WARNING(__func__<<"() "<<__LINE__<<" - No truth segment found");
            return Acts::Result<Acts::BoundTrackParameters>::failure(std::make_error_code(std::errc::invalid_argument));
        }
        const xAOD::TruthParticle* truthPart = getTruthMatchedParticle(*truthSeg);
        if (!truthPart) {
             ATH_MSG_WARNING(__func__<<"() "<<__LINE__<<" - No truth particle found");
            return Acts::Result<Acts::BoundTrackParameters>::failure(std::make_error_code(std::errc::invalid_argument));
        }
        const MuonGMR4::SpectrometerSector* msSector{m_detMgr->getSectorEnvelope(truthSeg->chamberIndex(),
                                                                    truthSeg->sector(),
                                                                    truthSeg->etaIndex())};
        const Acts::Surface& sectorSurf{msSector->surface()};
        const Amg::Vector3D firstPos{atFirstSurface(tgContext, *firstSeg, false)};
        ATH_MSG_VERBOSE(__func__<<"() "<<__LINE__<<" - First measurement "
            <<msSector->idHelperSvc()->toString(xAOD::identify(firstMeasurement(*firstSeg, false)))
            <<", position: "<<Amg::toString(firstPos));
 
        const Amg::Transform3D& oldTrf{sectorSurf.localToGlobalTransform(tgContext)};
        const Amg::Vector3D segDir = truthSeg->direction();
        const Amg::Vector3D locDir = oldTrf.inverse().linear() * segDir;
        const double pathLength = std::abs((truthSeg->position() - firstPos).dot(segDir)) + 10._cm;
 
        const Amg::Transform3D newTrf{oldTrf * Amg::getTranslate3D(-pathLength * locDir)};
        ATH_MSG_VERBOSE(__func__<<"() "<<__LINE__<<" - Create new surface in front of "<<msSector->identString()
                                <<", "<<Amg::toString(newTrf));
        auto shiftedSurf = Acts::Surface::makeShared<Acts::PlaneSurface>(newTrf);
 
        Acts::BoundVector locPars = SegmentFit::boundSegmentPars(tgContext, *m_detMgr, *truthSeg).parameters();
        static const SG::ConstAccessor<float> acc_pt{"pt"};
        locPars[Acts::eBoundQOverP] = truthPart->charge() / ActsTrk::energyToActs(acc_pt(*truthSeg) * std::cosh(truthPart->eta()));
        Acts::BoundTrackParameters result{shiftedSurf, locPars,
                                          Acts::BoundMatrix::Identity(), 
                                          Acts::ParticleHypothesis::muon()};
        using namespace Acts::detail::LineHelper;
        if (msgLvl(MSG::VERBOSE)) {
            std::stringstream outStream{};
            outStream<<"Start parameters:\n"<<result<<",\n"
                    <<result.referenceSurface().toString(tgContext)
                    <<"absolute momentum: "
                    <<result.absoluteMomentum()<<"/"<<ActsTrk::energyToActs(truthPart->pt()* std::cosh(truthPart->eta()))
                    <<", start point closure: "<<(result.position(tgContext) + pathLength * segDir - truthSeg->position()).mag()
                    <<", angle closure: "<<Amg::angle(result.direction(), segDir) / 1._degree
                    <<"\n\ndump measurements:\n";
 
            for (const xAOD::MuonSegment* segment : seed.segments()) {
                outStream<<" - Segment "<<printID(*segment)<<" @ "<<Amg::toString(segment->position())<<"+"
                         <<Amg::toString(segment->direction())<<std::endl;
                for (unsigned int m = 0; m < nMeasurements(*segment); ++m) {
                    const xAOD::UncalibratedMeasurement* meas = getMeasurement(*segment, m);
                    if (meas->type() == xAOD::UncalibMeasType::Other) {
                        continue;
                    }
                    const auto* mMeas = static_cast<const xAOD::MuonMeasurement*>(meas);
                    const Acts::Surface& surf{xAOD::muonSurface(meas)};
                    const double dist{surf.intersect(tgContext, result.position(tgContext), segDir, 
                                                      Acts::BoundaryTolerance::Infinite()).closest().pathLength()};
                    outStream<<" *** "<<m_detMgr->idHelperSvc()->toString(mMeas->identify())
                             <<" @ "<<Amg::toString(surf.localToGlobalTransform(tgContext) * mMeas->localMeasurementPos())
                             <<", center: "<<Amg::toString(surf.center(tgContext))
                             <<", travelled distance: "<<dist<<std::endl;
                }
            }
            ATH_MSG_VERBOSE(__func__<<"() "<<__LINE__<<" - Created start parameters:\n"<<outStream.str());
        }
        return result;                                             
    }

findTrackSeeds()

StatusCode MuonR4::TruthTrackSeederTool::findTrackSeeds ( const EventContext & ctx, std::vector< MsTrackSeed > & outSeeds ) const

finaloverridevirtual

Retrieves the segment container from StoreGate and constructs TrackSeeds from them.

The seed canddiates are pushed to the output seed container

Parameters

ctx	EventContext to access the xAOD::MuonSegmentContainer from store gate and additional conditions data if needed to construct the seed
outSeeds	Mutable reference to the container to whichh the seeds are pushed to.

Fill the truth seed map

Remove duplicate segments on the same station

Definition at line 39 of file TruthTrackSeederTool.cxx.

                                                                                             {
        const xAOD::MuonSegmentContainer* segments{nullptr};
        ATH_CHECK(SG::get(segments, m_segmentKey, ctx));
        std::unordered_map<const xAOD::TruthParticle*, std::vector<const xAOD::MuonSegment*>> truthSeeds{};
        for (const xAOD::MuonSegment* seg : *segments) {
            const xAOD::TruthParticle* truthPart = getTruthMatchedParticle(*seg);
            if (truthPart && truthPart->isMuon()) {
                truthSeeds[truthPart].push_back(seg);
            }    
        }
        for (auto& [truthPart, assocSegs] : truthSeeds) {
            std::ranges::sort(assocSegs, [](const xAOD::MuonSegment* a, const xAOD::MuonSegment* b){
                if (a->chamberIndex() != b->chamberIndex()) {
                    return a->chamberIndex() < b->chamberIndex();
                }
                return countHits(*a) > countHits(*b);
            });
            auto [begin, end] = std::ranges::unique(assocSegs, [](const xAOD::MuonSegment* a, const xAOD::MuonSegment* b){
                return a->chamberIndex() == b->chamberIndex();
            });
            assocSegs.erase(begin,end);
            if (assocSegs.size() < 2) {
                continue;
            }
            MsTrackSeed& seed = outSeeds.emplace_back(MsTrackSeed::Location::Barrel,
                                                      ExpandedSector{truthPart->phi()});
            std::ranges::for_each(assocSegs, [&seed](const xAOD::MuonSegment* seg) {
                seed.addSegment(seg);
            });
        }
 
        return StatusCode::SUCCESS;
    }

initialize()

StatusCode MuonR4::TruthTrackSeederTool::initialize ( )

finaloverridevirtual

Definition at line 32 of file TruthTrackSeederTool.cxx.

                                                {
        ATH_CHECK(m_segmentKey.initialize());
        ATH_CHECK(m_truthLinkKey.initialize());
        ATH_CHECK(detStore()->retrieve(m_detMgr));
        ATH_CHECK(m_ctxProvider.initialize());
        return StatusCode::SUCCESS;
    }

Member Data Documentation

m_ctxProvider

ActsTrk::ContextUtility MuonR4::TruthTrackSeederTool::m_ctxProvider {this}

private

Context utility to retrieve the geometry context.

Definition at line 50 of file TruthTrackSeederTool.h.

{this};

m_detMgr

MuonGMR4::MuonDetectorManager* MuonR4::TruthTrackSeederTool::m_detMgr {nullptr}

private

Instance to the muon detector manager.

Definition at line 48 of file TruthTrackSeederTool.h.

{nullptr};

m_segmentKey

SG::ReadHandleKey<xAOD::MuonSegmentContainer> MuonR4::TruthTrackSeederTool::m_segmentKey {this, "SegmentContainer", "MuonSegmentsFromR4" }

private

Declare the data dependency on the standard Mdt+Rpc+Tgc segment container & on the NSW segment container.

Definition at line 44 of file TruthTrackSeederTool.h.

{this, "SegmentContainer", "MuonSegmentsFromR4" };

m_truthLinkKey

SG::ReadDecorHandleKey<xAOD::MuonSegmentContainer> MuonR4::TruthTrackSeederTool::m_truthLinkKey {this, "TruthLinkKey", m_segmentKey, "truthParticleLink"}

private

Dependency on the truth particle link.

Definition at line 46 of file TruthTrackSeederTool.h.

{this, "TruthLinkKey", m_segmentKey, "truthParticleLink"};

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

• TruthTrackSeederTool.h
• TruthTrackSeederTool.cxx