MuonR4::MlMsTrackSeeder Class Reference

ITrackSeedingTool implementation which constructs seeds directly from sufficiently large ML-nominated segment components. More...

#include <MlMsTrackSeeder.h>

Inheritance diagram for MuonR4::MlMsTrackSeeder:

Collaboration diagram for MuonR4::MlMsTrackSeeder:

Public Member Functions
StatusCode	initialize () override final
StatusCode	findTrackSeeds (const EventContext &ctx, std::vector< MsTrackSeed > &outSeeds) const override final
	Retrieves the segment container from StoreGate and constructs TrackSeeds from them.
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
ToolHandle< ITrackSeedingTool >	m_seedParameterEstimator
SG::ReadHandleKey< xAOD::MuonSegmentContainer >	m_segmentKey
SG::ReadDecorHandleKey< xAOD::MuonSegmentContainer >	m_candidateDecorKey
Gaudi::Property< unsigned int >	m_minSegmentsPerCandidate
Gaudi::Property< unsigned int >	m_maxSegmentsPerCandidate
Gaudi::Property< unsigned int >	m_minLayers
Gaudi::Property< double >	m_minCosConsistency

Detailed Description

ITrackSeedingTool implementation which constructs seeds directly from sufficiently large ML-nominated segment components.

The wrapped conventional tool is used only for initial-parameter estimation; it never constructs seeds for this tool. Consequently MsTrackFindingAlg sees only the standard ITrackSeedingTool interface and selects this implementation entirely through job configuration.

Definition at line 26 of file MlMsTrackSeeder.h.

Member Function Documentation

estimateStartParameters()

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

finaloverride

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

Definition at line 114 of file MlMsTrackSeeder.cxx.

                                   {
  return m_seedParameterEstimator->estimateStartParameters(ctx, seed);
}

findTrackSeeds()

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

finaloverride

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.

Definition at line 35 of file MlMsTrackSeeder.cxx.

                                            {
  const xAOD::MuonSegmentContainer* segments{nullptr};
  ATH_CHECK(SG::get(segments, m_segmentKey, ctx));
 
  // The decoration payload is [componentId, isSeedAnchor].
  SG::ReadDecorHandle<xAOD::MuonSegmentContainer, std::vector<unsigned int>>
      componentAcc{m_candidateDecorKey, ctx};
  if (!componentAcc.isAvailable()) {
    ATH_MSG_DEBUG("No ML candidate decoration found");
    return StatusCode::SUCCESS;
  }
 
  std::map<unsigned int, MlComponent> components;
 
  for (const xAOD::MuonSegment* segment : *segments) {
    if (!segment) continue;
    const std::vector<unsigned int>& payload = componentAcc(*segment);
    if (payload.size() != 2 || payload[0] == 0) continue;
    MlComponent& component = components[payload[0]];
    component.segments.push_back(segment);
    if (payload[1] != 0) component.anchors.push_back(segment);
  }
 
  std::size_t acceptedComponents = 0;
  std::size_t constructedSeeds = 0;
  for (const auto& [componentId, component] : components) {
    if (component.segments.size() < m_minSegmentsPerCandidate.value() ||
        (m_maxSegmentsPerCandidate.value() != 0 &&
         component.segments.size() > m_maxSegmentsPerCandidate.value()) ||
        component.anchors.empty()) {
      continue;
    }
    ++acceptedComponents;
 
    for (const xAOD::MuonSegment* anchor : component.anchors) {
      const MsTrackSeed::Location location =
          Muon::MuonStationIndex::isBarrel(anchor->chamberIndex())
              ? MsTrackSeed::Location::Barrel
              : MsTrackSeed::Location::Endcap;
      MsTrackSeed seed{location, ExpandedSector{anchor->position().phi()}};
 
      // One segment per layer, best aligned with the anchor: the baseline seeder
      // only builds seeds that span several layers, and the fit rejects single-layer tracks.
      const Muon::MuonStationIndex::LayerIndex anchorLayer =
          Muon::MuonStationIndex::toLayerIndex(anchor->chamberIndex());
      std::map<Muon::MuonStationIndex::LayerIndex, std::pair<double, const xAOD::MuonSegment*>> bestPerLayer;
      for (const xAOD::MuonSegment* segment : component.segments) {
        if (segment == anchor) continue;
        const Muon::MuonStationIndex::LayerIndex layer =
            Muon::MuonStationIndex::toLayerIndex(segment->chamberIndex());
        if (layer == anchorLayer) continue;
        const double cosAngle = anchor->direction().dot(segment->direction());
        if (cosAngle < m_minCosConsistency.value()) continue;
        auto& best = bestPerLayer[layer];
        if (!best.second || cosAngle > best.first) best = {cosAngle, segment};
      }
      if (bestPerLayer.size() + 1 < m_minLayers.value()) continue;
 
      seed.addSegment(anchor);
      for (const auto& [layer, choice] : bestPerLayer) seed.addSegment(choice.second);
      seed.setPosition(anchor->position());
      outSeeds.push_back(std::move(seed));
      ++constructedSeeds;
    }
    ATH_MSG_VERBOSE("Constructed " << component.anchors.size()
                    << " seed(s) from ML component " << componentId
                    << " with " << component.segments.size()
                    << " segments");
  }
 
  ATH_MSG_DEBUG("Constructed " << constructedSeeds << " seed(s) from "
                << acceptedComponents << "/" << components.size()
                << " decorated ML component(s)");
  return StatusCode::SUCCESS;
}

initialize()

StatusCode MuonR4::MlMsTrackSeeder::initialize ( )

finaloverride

Definition at line 28 of file MlMsTrackSeeder.cxx.

                                       {
  ATH_CHECK(m_seedParameterEstimator.retrieve());
  ATH_CHECK(m_segmentKey.initialize());
  ATH_CHECK(m_candidateDecorKey.initialize());
  return StatusCode::SUCCESS;
}

Member Data Documentation

m_candidateDecorKey

SG::ReadDecorHandleKey<xAOD::MuonSegmentContainer> MuonR4::MlMsTrackSeeder::m_candidateDecorKey

private

Initial value:

{
      this, "CandidateDecoration", m_segmentKey, "trackCandidateIds",
      "Scheduler dependency on the ML candidate decoration"}

Definition at line 48 of file MlMsTrackSeeder.h.

                                                                    {
      this, "CandidateDecoration", m_segmentKey, "trackCandidateIds",
      "Scheduler dependency on the ML candidate decoration"};

m_maxSegmentsPerCandidate

Gaudi::Property<unsigned int> MuonR4::MlMsTrackSeeder::m_maxSegmentsPerCandidate

private

Initial value:

{
      this, "MaxSegmentsPerCandidate", 0,
      "Discard ML components with more than this many segments; zero disables the cap"}

Definition at line 53 of file MlMsTrackSeeder.h.

                                                       {
      this, "MaxSegmentsPerCandidate", 0,
      "Discard ML components with more than this many segments; zero disables the cap"};

m_minCosConsistency

Gaudi::Property<double> MuonR4::MlMsTrackSeeder::m_minCosConsistency

private

Initial value:

{
      this, "MinCosConsistency", 0.819,  
      "Minimum cos(angle) between a segment's direction and its seed anchor's "
      "direction for the segment to be included in the seed"}

Definition at line 58 of file MlMsTrackSeeder.h.

                                           {
      this, "MinCosConsistency", 0.819,  // cos(35 deg), matching SegmentEdgeClassifierTool's default MaxDeltaThetaDeg
      "Minimum cos(angle) between a segment's direction and its seed anchor's "
      "direction for the segment to be included in the seed"};

m_minLayers

Gaudi::Property<unsigned int> MuonR4::MlMsTrackSeeder::m_minLayers

private

Initial value:

{
      this, "MinLayers", 2, "Minimum number of distinct muon layers a seed must span"}

Definition at line 56 of file MlMsTrackSeeder.h.

                                         {
      this, "MinLayers", 2, "Minimum number of distinct muon layers a seed must span"};

m_minSegmentsPerCandidate

Gaudi::Property<unsigned int> MuonR4::MlMsTrackSeeder::m_minSegmentsPerCandidate

private

Initial value:

{
      this, "MinSegmentsPerCandidate", 2}

Definition at line 51 of file MlMsTrackSeeder.h.

                                                       {
      this, "MinSegmentsPerCandidate", 2};

m_seedParameterEstimator

ToolHandle<ITrackSeedingTool> MuonR4::MlMsTrackSeeder::m_seedParameterEstimator

private

Initial value:

{
      this, "BaselineSeeder", "",
      "Tool providing initial-parameter estimates for ML-built seeds"}

Definition at line 43 of file MlMsTrackSeeder.h.

                                                        {
      this, "BaselineSeeder", "",
      "Tool providing initial-parameter estimates for ML-built seeds"};

m_segmentKey

SG::ReadHandleKey<xAOD::MuonSegmentContainer> MuonR4::MlMsTrackSeeder::m_segmentKey

private

Initial value:

{
      this, "SegmentContainer", "MsSegments"}

Definition at line 46 of file MlMsTrackSeeder.h.

                                                        {
      this, "SegmentContainer", "MsSegments"};

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

• MlMsTrackSeeder.h
• MlMsTrackSeeder.cxx