MtdTruthAccumulator.cc

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// Author: Aurora Perego, Fabio Cossutti - aurora.perego@cern.ch, fabio.cossutti@ts.infn.it
// Date: 05/2023

#define DEBUG false
#define PRINT_DEBUG true

#if DEBUG
#pragma GCC diagnostic pop
#endif

#include <algorithm>
#include <iterator>
#include <exception>
#include <memory>

#include <numeric>  // for std::accumulate
#include <unordered_map>

#include "FWCore/Framework/interface/ConsumesCollector.h"
#include "FWCore/Framework/interface/ESWatcher.h"
#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Framework/interface/EventSetup.h"
#include "FWCore/Framework/interface/ProducesCollector.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/Utilities/interface/InputTag.h"

#include "DataFormats/ForwardDetId/interface/BTLDetId.h"
#include "DataFormats/ForwardDetId/interface/ETLDetId.h"
#include "DataFormats/HepMCCandidate/interface/GenParticle.h"
#include "DataFormats/Math/interface/GeantUnits.h"
#include "DataFormats/SiPixelDetId/interface/PixelSubdetector.h"
#include "DataFormats/SiStripDetId/interface/StripSubdetector.h"

#include "SimDataFormats/CaloAnalysis/interface/MtdCaloParticle.h"
#include "SimDataFormats/CaloAnalysis/interface/MtdCaloParticleFwd.h"
#include "SimDataFormats/CaloAnalysis/interface/MtdSimCluster.h"
#include "SimDataFormats/CaloAnalysis/interface/MtdSimClusterFwd.h"
#include "SimDataFormats/CaloAnalysis/interface/MtdSimLayerCluster.h"
#include "SimDataFormats/CaloAnalysis/interface/MtdSimLayerClusterFwd.h"
#include "SimDataFormats/CaloAnalysis/interface/MtdSimTrackster.h"
#include "SimDataFormats/CaloAnalysis/interface/MtdSimTracksterFwd.h"
#include "SimDataFormats/GeneratorProducts/interface/HepMCProduct.h"
#include "SimDataFormats/TrackingHit/interface/PSimHit.h"
#include "SimDataFormats/Vertex/interface/SimVertex.h"

#include "SimGeneral/MixingModule/interface/DecayGraph.h"
#include "SimGeneral/MixingModule/interface/DigiAccumulatorMixMod.h"
#include "SimGeneral/MixingModule/interface/DigiAccumulatorMixModFactory.h"
#include "SimGeneral/MixingModule/interface/PileUpEventPrincipal.h"
#include "SimGeneral/TrackingAnalysis/interface/EncodedTruthId.h"

#include "Geometry/MTDCommonData/interface/MTDTopologyMode.h"
#include "Geometry/Records/interface/MTDDigiGeometryRecord.h"
#include "Geometry/MTDGeometryBuilder/interface/MTDGeometry.h"
#include "Geometry/MTDGeometryBuilder/interface/MTDGeomUtil.h"
#include "Geometry/MTDNumberingBuilder/interface/MTDTopology.h"
#include "Geometry/MTDGeometryBuilder/interface/ProxyMTDTopology.h"
#include "Geometry/MTDGeometryBuilder/interface/RectangularMTDTopology.h"

namespace {
  using Index_t = unsigned;
  using Barcode_t = int;
  const std::string messageCategoryGraph_("MtdTruthAccumulatorGraphProducer");
}  // namespace

class MtdTruthAccumulator : public DigiAccumulatorMixMod {
public:
  explicit MtdTruthAccumulator(const edm::ParameterSet &config, edm::ProducesCollector, edm::ConsumesCollector &iC);

private:
  void initializeEvent(const edm::Event &event, const edm::EventSetup &setup) override;
  void accumulate(const edm::Event &event, const edm::EventSetup &setup) override;
  void accumulate(const PileUpEventPrincipal &event, const edm::EventSetup &setup, edm::StreamID const &) override;
  void finalizeEvent(edm::Event &event, const edm::EventSetup &setup) override;

  template <class T>
  void accumulateEvent(const T &event,
                       const edm::EventSetup &setup,
                       const edm::Handle<edm::HepMCProduct> &hepMCproduct);

  template <class T>
  void fillSimHits(std::vector<std::pair<uint64_t, const PSimHit *>> &returnValue,
                   std::unordered_map<int, std::map<uint64_t, std::tuple<float, float, LocalPoint>>> &simTrackDetIdMap,
                   const T &event,
                   const edm::EventSetup &setup);

  const std::string messageCategory_;

  std::unordered_map<uint64_t, float> m_detIdToTotalSimEnergy;  // keep track of cell normalizations
  std::unordered_multimap<Barcode_t, Index_t> m_simHitBarcodeToIndex;

  const unsigned int maximumPreviousBunchCrossing_;
  const unsigned int maximumSubsequentBunchCrossing_;

  const unsigned int bunchSpacing_;

  const edm::InputTag simTrackLabel_;
  const edm::InputTag simVertexLabel_;
  edm::Handle<std::vector<SimTrack>> hSimTracks;
  edm::Handle<std::vector<SimVertex>> hSimVertices;

  std::vector<edm::InputTag> collectionTags_;
  edm::InputTag genParticleLabel_;
  edm::InputTag hepMCproductLabel_;
  const edm::ESGetToken<MTDGeometry, MTDDigiGeometryRecord> geomToken_;
  const edm::ESGetToken<MTDTopology, MTDTopologyRcd> mtdtopoToken_;
  // edm::ESWatcher<MTDDigiGeometryRecord> geomWatcher_;

  mtd::MTDGeomUtil geomTools_;

  const double minEnergy_, maxPseudoRapidity_;
  const bool premixStage1_;

  bool isEtl_;

public:
  struct OutputCollections {
    std::unique_ptr<MtdSimClusterCollection> pSimClusters;
    std::unique_ptr<MtdCaloParticleCollection> pCaloParticles;
    std::unique_ptr<MtdSimLayerClusterCollection> pMtdSimLayerClusters;
    std::unique_ptr<MtdSimTracksterCollection> pMtdSimTracksters;
  };

  struct calo_particles {
    std::vector<uint32_t> sc_start_;
    std::vector<uint32_t> sc_stop_;

    void swap(calo_particles &oth) {
      sc_start_.swap(oth.sc_start_);
      sc_stop_.swap(oth.sc_stop_);
    }

    void clear() {
      sc_start_.clear();
      sc_stop_.clear();
    }
  };

private:
  const MTDGeometry *geom = nullptr;
  const MTDTopology *topology = nullptr;
  OutputCollections output_;
  calo_particles m_caloParticles;
};

/* Graph utility functions */

namespace {
  class CaloParticle_dfs_visitor : public boost::default_dfs_visitor {
  public:
    CaloParticle_dfs_visitor(
        MtdTruthAccumulator::OutputCollections &output,
        MtdTruthAccumulator::calo_particles &caloParticles,
        std::unordered_multimap<Barcode_t, Index_t> &simHitBarcodeToIndex,
        std::unordered_map<int, std::map<uint64_t, std::tuple<float, float, LocalPoint>>> &simTrackDetIdMap,
        std::unordered_map<uint32_t, float> &vertex_time_map,
        Selector selector)
        : output_(output),
          caloParticles_(caloParticles),
          simHitBarcodeToIndex_(simHitBarcodeToIndex),
          simTrackDetIdMap_(simTrackDetIdMap),
          vertex_time_map_(vertex_time_map),
          selector_(selector) {}
    template <typename Vertex, typename Graph>
    void discover_vertex(Vertex u, const Graph &g) {
      // If we reach the vertex 0, it means that we are backtracking with respect
      // to the first generation of stable particles: simply return;
      //    if (u == 0) return;
      print_vertex(u, g);
      auto const vertex_property = get(vertex_name, g, u);
      if (!vertex_property.simTrack)
        return;
      // -- loop over possible trackIdOffsets to save also sim clusters from non-direct hits
      for (unsigned int offset = 0; offset < 4; offset++) {
        auto trackIdx = vertex_property.simTrack->trackId();
        trackIdx += offset * (static_cast<int>(PSimHit::k_tidOffset));
        IfLogDebug(DEBUG, messageCategoryGraph_)
            << " Found " << simHitBarcodeToIndex_.count(trackIdx) << " associated simHits" << std::endl;
        if (simHitBarcodeToIndex_.count(trackIdx)) {
          output_.pSimClusters->emplace_back(*vertex_property.simTrack);
          auto &simcluster = output_.pSimClusters->back();
          std::unordered_map<uint64_t, float> acc_energy;
          for (auto const &hit_and_energy : simTrackDetIdMap_[trackIdx]) {
            acc_energy[hit_and_energy.first] += std::get<0>(hit_and_energy.second);
          }
          for (auto const &hit_and_energy : acc_energy) {
            simcluster.addHitAndFraction(hit_and_energy.first, hit_and_energy.second);
            simcluster.addHitEnergy(hit_and_energy.second);
            simcluster.addHitTime(std::get<1>(
                simTrackDetIdMap_[simcluster.g4Tracks()[0].trackId() +
                                  offset * (static_cast<int>(PSimHit::k_tidOffset))][hit_and_energy.first]));
            simcluster.addHitPosition(std::get<2>(
                simTrackDetIdMap_[simcluster.g4Tracks()[0].trackId() +
                                  offset * (static_cast<int>(PSimHit::k_tidOffset))][hit_and_energy.first]));
            simcluster.setTrackIdOffset(offset);
          }
        }
      }
    }

    template <typename Edge, typename Graph>
    void examine_edge(Edge e, const Graph &g) {
      auto src = source(e, g);
      auto vertex_property = get(vertex_name, g, src);
      if (src == 0 or (vertex_property.simTrack == nullptr)) {
        auto edge_property = get(edge_weight, g, e);
        IfLogDebug(DEBUG, messageCategoryGraph_) << "Considering CaloParticle: " << edge_property.simTrack->trackId();
        if (selector_(edge_property)) {
          IfLogDebug(DEBUG, messageCategoryGraph_) << "Adding CaloParticle: " << edge_property.simTrack->trackId();
          output_.pCaloParticles->emplace_back(*(edge_property.simTrack));
          output_.pCaloParticles->back().addSimTime(vertex_time_map_[(edge_property.simTrack)->vertIndex()]);
          caloParticles_.sc_start_.push_back(output_.pSimClusters->size());
        }
      }
    }

    template <typename Edge, typename Graph>
    void finish_edge(Edge e, const Graph &g) {
      auto src = source(e, g);
      auto vertex_property = get(vertex_name, g, src);
      if (src == 0 or (vertex_property.simTrack == nullptr)) {
        auto edge_property = get(edge_weight, g, e);
        if (selector_(edge_property)) {
          caloParticles_.sc_stop_.push_back(output_.pSimClusters->size());
        }
      }
    }

  private:
    MtdTruthAccumulator::OutputCollections &output_;
    MtdTruthAccumulator::calo_particles &caloParticles_;
    std::unordered_multimap<Barcode_t, Index_t> &simHitBarcodeToIndex_;
    std::unordered_map<int, std::map<uint64_t, std::tuple<float, float, LocalPoint>>> &simTrackDetIdMap_;
    std::unordered_map<uint32_t, float> &vertex_time_map_;
    Selector selector_;
  };
}  // Namespace

MtdTruthAccumulator::MtdTruthAccumulator(const edm::ParameterSet &config,
                                         edm::ProducesCollector producesCollector,
                                         edm::ConsumesCollector &iC)
    : messageCategory_("MtdTruthAccumulator"),
      maximumPreviousBunchCrossing_(config.getParameter<unsigned int>("maximumPreviousBunchCrossing")),
      maximumSubsequentBunchCrossing_(config.getParameter<unsigned int>("maximumSubsequentBunchCrossing")),
      bunchSpacing_(config.getParameter<unsigned int>("bunchspace")),
      simTrackLabel_(config.getParameter<edm::InputTag>("simTrackCollection")),
      simVertexLabel_(config.getParameter<edm::InputTag>("simVertexCollection")),
      collectionTags_(),
      genParticleLabel_(config.getParameter<edm::InputTag>("genParticleCollection")),
      hepMCproductLabel_(config.getParameter<edm::InputTag>("HepMCProductLabel")),
      geomToken_(iC.esConsumes<MTDGeometry, MTDDigiGeometryRecord>()),
      mtdtopoToken_(iC.esConsumes<MTDTopology, MTDTopologyRcd>()),
      minEnergy_(config.getParameter<double>("MinEnergy")),
      maxPseudoRapidity_(config.getParameter<double>("MaxPseudoRapidity")),
      premixStage1_(config.getParameter<bool>("premixStage1")) {
  iC.consumes<std::vector<SimTrack>>(simTrackLabel_);
  iC.consumes<std::vector<SimVertex>>(simVertexLabel_);
  iC.consumes<std::vector<reco::GenParticle>>(genParticleLabel_);
  iC.consumes<std::vector<int>>(genParticleLabel_);
  iC.consumes<std::vector<int>>(hepMCproductLabel_);

  // Fill the collection tags
  const edm::ParameterSet &simHitCollectionConfig = config.getParameterSet("simHitCollections");
  std::vector<std::string> parameterNames = simHitCollectionConfig.getParameterNames();

  for (auto const &parameterName : parameterNames) {
    std::vector<edm::InputTag> tags = simHitCollectionConfig.getParameter<std::vector<edm::InputTag>>(parameterName);
    collectionTags_.insert(collectionTags_.end(), tags.begin(), tags.end());
  }

  for (auto const &collectionTag : collectionTags_) {
    iC.consumes<std::vector<PSimHit>>(collectionTag);
    isEtl_ = (collectionTag.instance().find("FastTimerHitsEndcap") != std::string::npos);
  }

  producesCollector.produces<MtdSimClusterCollection>("MergedMtdTruth");
  producesCollector.produces<MtdSimLayerClusterCollection>("MergedMtdTruthLC");
  producesCollector.produces<MtdSimTracksterCollection>("MergedMtdTruthST");
  producesCollector.produces<MtdCaloParticleCollection>("MergedMtdTruth");
  if (premixStage1_) {
    producesCollector.produces<std::vector<std::pair<uint64_t, float>>>("MergedMtdTruth");
  }
}

void MtdTruthAccumulator::initializeEvent(edm::Event const &event, edm::EventSetup const &setup) {
  output_.pSimClusters = std::make_unique<MtdSimClusterCollection>();
  output_.pCaloParticles = std::make_unique<MtdCaloParticleCollection>();

  output_.pMtdSimLayerClusters = std::make_unique<MtdSimLayerClusterCollection>();
  output_.pMtdSimTracksters = std::make_unique<MtdSimTracksterCollection>();

  m_detIdToTotalSimEnergy.clear();

  auto geometryHandle = setup.getTransientHandle(geomToken_);
  geom = geometryHandle.product();

  auto topologyHandle = setup.getTransientHandle(mtdtopoToken_);
  topology = topologyHandle.product();

  geomTools_.setGeometry(geom);
  geomTools_.setTopology(topology);
}

void MtdTruthAccumulator::accumulate(edm::Event const &event, edm::EventSetup const &setup) {
  edm::Handle<edm::HepMCProduct> hepmc;
  event.getByLabel(hepMCproductLabel_, hepmc);

  edm::LogInfo(messageCategory_) << " MtdTruthAccumulator::accumulate (signal)";
  accumulateEvent(event, setup, hepmc);
}

void MtdTruthAccumulator::accumulate(PileUpEventPrincipal const &event,
                                     edm::EventSetup const &setup,
                                     edm::StreamID const &) {
  if (event.bunchCrossing() >= -static_cast<int>(maximumPreviousBunchCrossing_) &&
      event.bunchCrossing() <= static_cast<int>(maximumSubsequentBunchCrossing_)) {
    // simply create empty handle as we do not have a HepMCProduct in PU anyway
    edm::Handle<edm::HepMCProduct> hepmc;
    edm::LogInfo(messageCategory_) << " MtdTruthAccumulator::accumulate (pileup) bunchCrossing="
                                   << event.bunchCrossing();
    accumulateEvent(event, setup, hepmc);
  } else {
    edm::LogInfo(messageCategory_) << "Skipping pileup event for bunch crossing " << event.bunchCrossing();
  }
}

void MtdTruthAccumulator::finalizeEvent(edm::Event &event, edm::EventSetup const &setup) {
  using namespace geant_units::operators;

  edm::LogInfo(messageCategory_) << "Adding " << output_.pSimClusters->size() << " SimParticles and "
                                 << output_.pCaloParticles->size() << " CaloParticles to the event.";

  // We need to normalize the hits and energies into hits and fractions (since
  // we have looped over all pileup events)
  // For premixing stage1 we keep the energies, they will be normalized to
  // fractions in stage2

  if (premixStage1_) {
    auto totalEnergies = std::make_unique<std::vector<std::pair<uint64_t, float>>>();
    totalEnergies->reserve(m_detIdToTotalSimEnergy.size());
    std::copy(m_detIdToTotalSimEnergy.begin(), m_detIdToTotalSimEnergy.end(), std::back_inserter(*totalEnergies));
    std::sort(totalEnergies->begin(), totalEnergies->end());
    event.put(std::move(totalEnergies), "MergedMtdTruth");
  } else {
    for (auto &sc : *(output_.pSimClusters)) {
      auto hitsAndEnergies = sc.hits_and_fractions();
      sc.clearHitsAndFractions();
      sc.clearHitsEnergy();
      for (auto &hAndE : hitsAndEnergies) {
        const float totalenergy = m_detIdToTotalSimEnergy[hAndE.first];
        float fraction = 0.;
        if (totalenergy > 0)
          fraction = hAndE.second / totalenergy;
        else
          edm::LogWarning(messageCategory_)
              << "TotalSimEnergy for hit " << hAndE.first << " is 0! The fraction for this hit cannot be computed.";
        sc.addHitAndFraction(hAndE.first, fraction);
        sc.addHitEnergy(hAndE.second);
      }
    }
  }

#ifdef PRINT_DEBUG
  IfLogDebug(DEBUG, messageCategory_) << "SIMCLUSTERS LIST:" << std::endl;
  for (const auto &sc : *(output_.pSimClusters)) {
    IfLogDebug(DEBUG, messageCategory_) << std::fixed << std::setprecision(3) << "SimCluster from CP with:"
                                        << "\n  charge " << sc.charge() << "\n  pdgId  " << sc.pdgId() << "\n  energy "
                                        << sc.energy() << " GeV\n  eta    " << sc.eta() << "\n  phi    " << sc.phi()
                                        << "\n  number of cells = " << sc.hits_and_fractions().size() << std::endl;
    for (unsigned int i = 0; i < sc.hits_and_fractions().size(); ++i) {
      DetId id(sc.detIds_and_rows()[i].first);
      IfLogDebug(DEBUG, messageCategory_)
          << std::fixed << std::setprecision(3) << " hit " << id.rawId() << " on layer " << geomTools_.layer(id)
          << " module " << geomTools_.module(id) << " row " << (unsigned int)(sc.detIds_and_rows()[i].second).first
          << " col " << (unsigned int)(sc.detIds_and_rows()[i].second).second << " at time "
          << sc.hits_and_times()[i].second << " ns" << std::endl;
    }
    IfLogDebug(DEBUG, messageCategory_) << "--------------\n";
  }
  IfLogDebug(DEBUG, messageCategory_) << std::endl;
#endif

  // save the SimCluster orphan handle so we can fill the calo particles
  auto scHandle = event.put(std::move(output_.pSimClusters), "MergedMtdTruth");

  // reserve for the best case scenario: already splitted
  output_.pMtdSimLayerClusters->reserve(scHandle->size());
  output_.pMtdSimTracksters->reserve(scHandle->size());

  uint32_t SC_index = 0;
  uint32_t LC_index = 0;
  for (const auto &sc : *scHandle) {
    auto const &hAndF = sc.hits_and_fractions();
    auto const &hAndE = sc.hits_and_energies();
    auto const &hAndT = sc.hits_and_times();
    auto const &hAndP = sc.hits_and_positions();
    auto const &hAndR = sc.detIds_and_rows();
    // create a vector with the indices of the hits in the simCluster
    std::vector<int> indices(hAndF.size());
    std::iota(indices.begin(), indices.end(), 0);
    // sort the hits indices based on the unique indices created before
    std::sort(indices.begin(), indices.end(), [&](int a, int b) { return hAndF[a].first < hAndF[b].first; });

    // now split the sc: loop on the sorted indices and save the first hit in a
    // temporary simCluster. If the following hit is in the same module and row (column),
    // but next column (row) put it in the temporary simcluster as well, otherwise
    // put the temporary simcluster in the collection and start creating a new one
    std::vector<uint32_t> LC_indices;
    MtdSimLayerCluster tmpLC(sc.g4Tracks()[0]);
    int prev = indices[0];
    DetId prevId(hAndR[prev].first);

    float SimLCenergy = 0.;
    float SimLCx = 0., SimLCy = 0., SimLCz = 0.;

    auto push_back_hit = [&](const int &ind) {
      tmpLC.addHitAndFraction(hAndF[ind].first, hAndF[ind].second);
      tmpLC.addHitEnergy(hAndE[ind].second);
      tmpLC.addHitTime(hAndT[ind].second);
      tmpLC.addHitPosition(hAndP[ind].second);
    };

    auto update_clu_info = [&](const int &ind) {
      double energy = hAndE[ind].second;
      auto position = hAndP[ind].second;
      if (geomTools_.isBTL((DetId)hAndR[ind].first)) {
        BTLDetId detId{(DetId)hAndR[ind].first};
        DetId geoId = detId.geographicalId(MTDTopologyMode::crysLayoutFromTopoMode(topology->getMTDTopologyMode()));
        const MTDGeomDet *thedet = geom->idToDet(geoId);
        const ProxyMTDTopology &topoproxy = static_cast<const ProxyMTDTopology &>(thedet->topology());
        const RectangularMTDTopology &topo = static_cast<const RectangularMTDTopology &>(topoproxy.specificTopology());
        position =
            topo.pixelToModuleLocalPoint(hAndP[ind].second, (hAndR[ind].second).first, (hAndR[ind].second).second);
      }
      SimLCenergy += energy;
      SimLCx += position.x() * energy;
      SimLCy += position.y() * energy;
      SimLCz += position.z() * energy;
    };

    auto push_back_clu = [&](const uint32_t &SC_index, uint32_t &LC_index) {
      tmpLC.addCluEnergy(SimLCenergy);
      LocalPoint SimLCpos(SimLCx / SimLCenergy, SimLCy / SimLCenergy, SimLCz / SimLCenergy);
      tmpLC.addCluLocalPos(SimLCpos);
      SimLCenergy = 0.;
      SimLCx = 0.;
      SimLCy = 0.;
      SimLCz = 0.;
      tmpLC.addCluIndex(SC_index);
      tmpLC.computeClusterTime();
      tmpLC.setTrackIdOffset(sc.trackIdOffset());  // add trackIdoffset
      output_.pMtdSimLayerClusters->push_back(tmpLC);
      LC_indices.push_back(LC_index);
      LC_index++;
      tmpLC.clear();
    };

    // fill tmpLC with the first hit
    push_back_hit(prev);
    update_clu_info(prev);
    for (const auto &ind : indices) {
      if (ind == indices[0])
        continue;
      DetId id(hAndR[ind].first);
      if (geomTools_.isETL(id) != geomTools_.isETL(prevId) or geomTools_.layer(id) != geomTools_.layer(prevId) or
          geomTools_.module(id) != geomTools_.module(prevId) or
          ((hAndR[ind].second).first == (hAndR[prev].second).first and
           (hAndR[ind].second).second != (hAndR[prev].second).second + 1) or
          ((hAndR[ind].second).second == (hAndR[prev].second).second and
           (hAndR[ind].second).first != (hAndR[prev].second).first + 1)) {
        // the next hit is not adjacent to the previous one, put the current temporary cluster in the collection
        // and the hit will be put in an empty temporary cluster
        push_back_clu(SC_index, LC_index);
      }
      // add the hit to the temporary cluster
      push_back_hit(ind);
      update_clu_info(ind);
      prev = ind;
      DetId newId(hAndR[prev].first);
      prevId = newId;
    }
    // add the remaining temporary cluster to the collection
    push_back_clu(SC_index, LC_index);

    // now the simTrackster: find position and time of the first simHit
    // bc right now there is no method to ask the simTrack for pos/time
    // at MTD entrance
    float timeAtEntrance = 99.;
    uint32_t idAtEntrance = 0;
    for (uint32_t i = 0; i < (uint32_t)hAndT.size(); i++) {
      if (hAndT[i].second < timeAtEntrance) {
        timeAtEntrance = hAndT[i].second;
        idAtEntrance = i;
      }
    }

    // sort LCs in the SimTrackster by time
    auto &MtdSimLayerClusters = output_.pMtdSimLayerClusters;
    std::sort(LC_indices.begin(), LC_indices.end(), [&MtdSimLayerClusters](int i, int j) {
      return (*MtdSimLayerClusters)[i].simLCTime() < (*MtdSimLayerClusters)[j].simLCTime();
    });

    GlobalPoint posAtEntrance = geomTools_
                                    .position((DetId)hAndR[idAtEntrance].first,
                                              (hAndR[idAtEntrance].second).first,
                                              (hAndR[idAtEntrance].second).second)
                                    .second;
    output_.pMtdSimTracksters->emplace_back(sc, LC_indices, timeAtEntrance, posAtEntrance);
    SC_index++;
  }

#ifdef PRINT_DEBUG
  IfLogDebug(DEBUG, messageCategory_) << "SIMLAYERCLUSTERS LIST: \n";
  for (auto &sc : *output_.pMtdSimLayerClusters) {
    IfLogDebug(DEBUG, messageCategory_) << std::fixed << std::setprecision(3) << "SimLayerCluster with:"
                                        << "\n  CP charge " << sc.charge() << "\n  CP pdgId  " << sc.pdgId()
                                        << "\n  CP energy " << sc.energy() << " GeV\n  CP eta    " << sc.eta()
                                        << "\n  CP phi    " << sc.phi()
                                        << "\n  number of cells = " << sc.hits_and_fractions().size() << std::endl;
    for (unsigned int i = 0; i < sc.hits_and_fractions().size(); ++i) {
      DetId id(sc.detIds_and_rows()[i].first);
      IfLogDebug(DEBUG, messageCategory_)
          << std::fixed << std::setprecision(3) << " hit " << sc.detIds_and_rows()[i].first << " on layer "
          << geomTools_.layer(id) << " at time " << sc.hits_and_times()[i].second << " ns" << std::endl;
    }
    IfLogDebug(DEBUG, messageCategory_) << std::fixed << std::setprecision(3) << "  Cluster time " << sc.simLCTime()
                                        << " ns \n Cluster pos" << sc.simLCPos() << " cm\n"
                                        << std::fixed << std::setprecision(6) << " Cluster energy "
                                        << convertUnitsTo(0.001_MeV, sc.simLCEnergy()) << " MeV" << std::endl;
    IfLogDebug(DEBUG, messageCategory_) << "--------------\n";
  }
  IfLogDebug(DEBUG, messageCategory_) << std::endl;

  IfLogDebug(DEBUG, messageCategory_) << "SIMTRACKSTERS LIST: \n";
  for (auto &sc : *output_.pMtdSimTracksters) {
    IfLogDebug(DEBUG, messageCategory_) << std::fixed << std::setprecision(3) << "SimTrackster with:"
                                        << "\n  CP charge " << sc.charge() << "\n  CP pdgId  " << sc.pdgId()
                                        << "\n  CP energy " << sc.energy() << " GeV\n  CP eta    " << sc.eta()
                                        << "\n  CP phi    " << sc.phi()
                                        << "\n number of layer clusters = " << sc.numberOfClusters()
                                        << "\n time of first simhit " << sc.time() << " ns\n position of first simhit"
                                        << sc.position() << "cm" << std::endl;
    IfLogDebug(DEBUG, messageCategory_) << "  LCs indices: ";
    for (const auto &lc : sc.clusters())
      IfLogDebug(DEBUG, messageCategory_) << lc << ", ";
    IfLogDebug(DEBUG, messageCategory_) << "\n--------------\n";
  }
  IfLogDebug(DEBUG, messageCategory_) << std::endl;
#endif

  event.put(std::move(output_.pMtdSimLayerClusters), "MergedMtdTruthLC");
  event.put(std::move(output_.pMtdSimTracksters), "MergedMtdTruthST");

  // now fill the calo particles
  for (unsigned i = 0; i < output_.pCaloParticles->size(); ++i) {
    auto &cp = (*output_.pCaloParticles)[i];
    for (unsigned j = m_caloParticles.sc_start_[i]; j < m_caloParticles.sc_stop_[i]; ++j) {
      edm::Ref<MtdSimClusterCollection> ref(scHandle, j);
      cp.addSimCluster(ref);
    }
  }
  event.put(std::move(output_.pCaloParticles), "MergedMtdTruth");

  calo_particles().swap(m_caloParticles);

  std::unordered_map<uint64_t, float>().swap(m_detIdToTotalSimEnergy);
  std::unordered_multimap<Barcode_t, Index_t>().swap(m_simHitBarcodeToIndex);
}

template <class T>
void MtdTruthAccumulator::accumulateEvent(const T &event,
                                          const edm::EventSetup &setup,
                                          const edm::Handle<edm::HepMCProduct> &hepMCproduct) {
  edm::Handle<std::vector<reco::GenParticle>> hGenParticles;
  edm::Handle<std::vector<int>> hGenParticleIndices;

  event.getByLabel(simTrackLabel_, hSimTracks);
  event.getByLabel(simVertexLabel_, hSimVertices);

  event.getByLabel(genParticleLabel_, hGenParticles);
  event.getByLabel(genParticleLabel_, hGenParticleIndices);

  std::vector<std::pair<uint64_t, const PSimHit *>> simHitPointers;
  std::unordered_map<int, std::map<uint64_t, std::tuple<float, float, LocalPoint>>> simTrackDetIdMap;
  fillSimHits(simHitPointers, simTrackDetIdMap, event, setup);

  // Clear maps from previous event fill them for this one
  m_simHitBarcodeToIndex.clear();
  for (unsigned int i = 0; i < simHitPointers.size(); ++i) {
    m_simHitBarcodeToIndex.emplace(simHitPointers[i].second->trackId(), i);
  }

  auto const &tracks = *hSimTracks;
  auto const &vertices = *hSimVertices;
  std::unordered_map<int, int> trackid_to_track_index;
  std::unordered_map<uint32_t, float> vertex_time_map;
  DecayChain decay;

  for (uint32_t i = 0; i < vertices.size(); i++) {
    vertex_time_map[i] = vertices[i].position().t() * 1e9 + event.bunchCrossing() * static_cast<int>(bunchSpacing_);
  }

  IfLogDebug(DEBUG, messageCategory_) << " TRACKS" << std::endl;
  int idx = 0;
  for (auto const &t : tracks) {
    IfLogDebug(DEBUG, messageCategory_) << " " << idx << "\t" << t.trackId() << "\t" << t << std::endl;
    trackid_to_track_index[t.trackId()] = idx;
    idx++;
  }

  idx = 0;
  std::vector<int> used_sim_tracks(tracks.size(), 0);
  std::vector<int> collapsed_vertices(vertices.size(), 0);
  IfLogDebug(DEBUG, messageCategory_) << " VERTICES" << std::endl;
  for (auto const &v : vertices) {
    IfLogDebug(DEBUG, messageCategory_) << " " << idx++ << "\t" << v << std::endl;
    if (v.parentIndex() != -1) {
      auto const trk_idx = trackid_to_track_index[v.parentIndex()];
      auto origin_vtx = tracks[trk_idx].vertIndex();
      if (used_sim_tracks[trk_idx]) {
        // collapse the vertex into the original first vertex we saw associated
        // to this track. Omit adding the edge in order to avoid double
        // counting of the very same particles  and its associated hits.
        collapsed_vertices[v.vertexId()] = used_sim_tracks[trk_idx];
        continue;
      }
      // Perform the actual vertex collapsing, if needed.
      if (collapsed_vertices[origin_vtx])
        origin_vtx = collapsed_vertices[origin_vtx];
      add_edge(
          origin_vtx, v.vertexId(), EdgeProperty(&tracks[trk_idx], simTrackDetIdMap[v.parentIndex()].size(), 0), decay);
      used_sim_tracks[trk_idx] = v.vertexId();
    }
  }
  // Build the motherParticle property to each vertex
  auto const &vertexMothersProp = get(vertex_name, decay);
  // Now recover the particles that did not decay. Append them with an index
  // bigger than the size of the generated vertices.
  int offset = vertices.size();
  for (size_t i = 0; i < tracks.size(); ++i) {
    if (!used_sim_tracks[i]) {
      auto origin_vtx = tracks[i].vertIndex();
      // Perform the actual vertex collapsing, if needed.
      if (collapsed_vertices[origin_vtx])
        origin_vtx = collapsed_vertices[origin_vtx];
      add_edge(origin_vtx, offset, EdgeProperty(&tracks[i], simTrackDetIdMap[tracks[i].trackId()].size(), 0), decay);
      // The properties for "fake" vertices associated to stable particles have
      // to be set inside this loop, since they do not belong to the vertices
      // collection and would be skipped by that loop (coming next)
      put(vertexMothersProp, offset, VertexProperty(&tracks[i], 0));
      offset++;
    }
  }
  for (auto const &v : vertices) {
    if (v.parentIndex() != -1) {
      // Skip collapsed_vertices
      if (collapsed_vertices[v.vertexId()])
        continue;
      put(vertexMothersProp, v.vertexId(), VertexProperty(&tracks[trackid_to_track_index[v.parentIndex()]], 0));
    }
  }
  SimHitsAccumulator_dfs_visitor vis;
  depth_first_search(decay, visitor(vis));
  CaloParticle_dfs_visitor caloParticleCreator(
      output_,
      m_caloParticles,
      m_simHitBarcodeToIndex,
      simTrackDetIdMap,
      vertex_time_map,
      [&](EdgeProperty &edge_property) -> bool {
        // Apply selection on SimTracks in order to promote them to be
        // CaloParticles. The function returns TRUE if the particle satisfies
        // the selection, FALSE otherwise. Therefore the correct logic to select
        // the particle is to ask for TRUE as return value.
        return (edge_property.cumulative_simHits != 0 and !edge_property.simTrack->noGenpart() and
                edge_property.simTrack->momentum().E() > minEnergy_ and
                std::abs(edge_property.simTrack->momentum().Eta()) < maxPseudoRapidity_);
      });
  depth_first_search(decay, visitor(caloParticleCreator));

#if DEBUG
  boost::write_graphviz(std::cout,
                        decay,
                        make_label_writer(make_transform_value_property_map(&graphviz_vertex, get(vertex_name, decay))),
                        make_label_writer(make_transform_value_property_map(&graphviz_edge, get(edge_weight, decay))));
#endif
}

template <class T>
void MtdTruthAccumulator::fillSimHits(
    std::vector<std::pair<uint64_t, const PSimHit *>> &returnValue,
    std::unordered_map<int, std::map<uint64_t, std::tuple<float, float, LocalPoint>>> &simTrackDetIdMap,
    const T &event,
    const edm::EventSetup &setup) {
  using namespace geant_units::operators;
  using namespace angle_units::operators;
  for (auto const &collectionTag : collectionTags_) {
    edm::Handle<std::vector<PSimHit>> hSimHits;
    event.getByLabel(collectionTag, hSimHits);

    for (auto const &simHit : *hSimHits) {
      DetId id(0);

      // --- Use only hits compatible with the in-time bunch-crossing
      if (simHit.tof() < 0 || simHit.tof() > 25.)
        continue;

      id = simHit.detUnitId();

      if (id == DetId(0)) {
        edm::LogWarning(messageCategory_) << "Invalid DetId for the current simHit!";
        continue;
      }

      if (simHit.trackId() == 0) {
        continue;
      }

      returnValue.emplace_back(id, &simHit);

      // get an unique id: for BTL the detId is unique (one for each crystal), for ETL the detId is not enough
      // also row and column are needed. An unique number is created from detId, row, col
      // Get row and column
      const auto &position = simHit.localPosition();

      LocalPoint simscaled(convertMmToCm(position.x()), convertMmToCm(position.y()), convertMmToCm(position.z()));
      std::pair<uint8_t, uint8_t> pixel = geomTools_.pixelInModule(id, simscaled);
      // create the unique id
      uint64_t uniqueId = static_cast<uint64_t>(id.rawId()) << 32;
      uniqueId |= pixel.first << 16;
      uniqueId |= pixel.second;

      std::get<0>(simTrackDetIdMap[simHit.trackId()][uniqueId]) += simHit.energyLoss();
      m_detIdToTotalSimEnergy[uniqueId] += simHit.energyLoss();
      // --- Get the time of the first SIM hit in the cell
      if (std::get<1>(simTrackDetIdMap[simHit.trackId()][uniqueId]) == 0. ||
          simHit.tof() < std::get<1>(simTrackDetIdMap[simHit.trackId()][uniqueId])) {
        std::get<1>(simTrackDetIdMap[simHit.trackId()][uniqueId]) = simHit.tof();
      }

      float xSim = std::get<2>(simTrackDetIdMap[simHit.trackId()][uniqueId]).x() + simscaled.x() * simHit.energyLoss();
      float ySim = std::get<2>(simTrackDetIdMap[simHit.trackId()][uniqueId]).y() + simscaled.y() * simHit.energyLoss();
      float zSim = std::get<2>(simTrackDetIdMap[simHit.trackId()][uniqueId]).z() + simscaled.z() * simHit.energyLoss();
      LocalPoint posSim(xSim, ySim, zSim);
      std::get<2>(simTrackDetIdMap[simHit.trackId()][uniqueId]) = posSim;

#ifdef PRINT_DEBUG
      IfLogDebug(DEBUG, messageCategory_)
          << "hitId " << id.rawId() << " from track " << simHit.trackId() << " in layer " << geomTools_.layer(id)
          << ", module " << geomTools_.module(id) << ", pixel ( " << (int)geomTools_.pixelInModule(id, simscaled).first
          << ", " << (int)geomTools_.pixelInModule(id, simscaled).second << " )\n global pos(cm) "
          << geomTools_.globalPosition(id, simscaled) << ", time(ns) " << simHit.tof() << ", energy(MeV) "
          << convertUnitsTo(0.001_MeV, simHit.energyLoss()) << std::endl;
#endif
    }  // end of loop over simHits

  }  // End of loop over InputTags

  for (auto &tkIt : simTrackDetIdMap) {
    for (auto &uIt : tkIt.second) {
      float accEnergy = std::get<0>(uIt.second);
      float xSim = std::get<2>(uIt.second).x() / accEnergy;
      float ySim = std::get<2>(uIt.second).y() / accEnergy;
      float zSim = std::get<2>(uIt.second).z() / accEnergy;
      LocalPoint posSim(xSim, ySim, zSim);
      std::get<2>(uIt.second) = posSim;
    }
  }
}

// Register with the framework
DEFINE_DIGI_ACCUMULATOR(MtdTruthAccumulator);