L1TrackJetProducer.cc

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// Original simulation Author:  Rishi Patel
//
// Rewritting/improvements:  George Karathanasis,
//                           georgios.karathanasis@cern.ch, CU Boulder
//                           Claire Savard (claire.savard@colorado.edu)
//
//         Created:  Wed, 01 Aug 2018 14:01:41 GMT
//         Latest update: Nov 2023 (by CS)
//
// Track jets are clustered in a two-layer process, first by clustering in phi,
// then by clustering in eta. The code proceeds as following: putting all tracks
// in a grid of eta vs phi space, and then cluster them. Finally we merge the cl
// usters when needed. The code is improved to use the same module between emula
// tion and simulation was also improved, with bug fixes and being faster.
// Introduction to object (p10-13):
// https://indico.cern.ch/event/791517/contributions/3341650/attachments/1818736/2973771/TrackBasedAlgos_L1TMadrid_MacDonald.pdf
// New and improved version: https://indico.cern.ch/event/1203796/contributions/5073056/attachments/2519806/4333006/trackjet_emu.pdf

// system include files
#include "DataFormats/Common/interface/Ref.h"
#include "DataFormats/Common/interface/RefVector.h"
#include "DataFormats/L1TCorrelator/interface/TkJet.h"
#include "DataFormats/L1TCorrelator/interface/TkJetFwd.h"
#include "DataFormats/L1TrackTrigger/interface/TTTypes.h"
#include "DataFormats/L1TrackTrigger/interface/TTTrack.h"
#include "DataFormats/L1Trigger/interface/VertexWord.h"

// user include files
#include "FWCore/Framework/interface/Frameworkfwd.h"
#include "FWCore/Framework/interface/stream/EDProducer.h"
#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Framework/interface/EventSetup.h"
#include "FWCore/Framework/interface/MakerMacros.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/Utilities/interface/StreamID.h"
#include "Geometry/Records/interface/TrackerDigiGeometryRecord.h"

//own headers
#include "L1TrackJetClustering.h"

using namespace std;
using namespace edm;
using namespace l1t;
using namespace l1ttrackjet;

class L1TrackJetProducer : public stream::EDProducer<> {
public:
  explicit L1TrackJetProducer(const ParameterSet &);
  ~L1TrackJetProducer() override = default;
  typedef TTTrack<Ref_Phase2TrackerDigi_> L1TTTrackType;
  typedef vector<L1TTTrackType> L1TTTrackCollectionType;
  typedef edm::RefVector<L1TTTrackCollectionType> L1TTTrackRefCollectionType;
  static void fillDescriptions(ConfigurationDescriptions &descriptions);

private:
  void produce(Event &, const EventSetup &) override;

  // ----------member data ---------------------------

  vector<Ptr<L1TTTrackType>> L1TrkPtrs_;
  const float trkZMax_;
  const float trkPtMax_;
  const float trkEtaMax_;
  const int lowpTJetMinTrackMultiplicity_;
  const float lowpTJetThreshold_;
  const int highpTJetMinTrackMultiplicity_;
  const float highpTJetThreshold_;
  const int zBins_;
  const int etaBins_;
  const int phiBins_;
  const double minTrkJetpT_;
  float zStep_;
  float etaStep_;
  float phiStep_;
  const bool displaced_;
  const float d0CutNStubs4_;
  const float d0CutNStubs5_;
  const int nDisplacedTracks_;

  const EDGetTokenT<L1TTTrackRefCollectionType> trackToken_;
};

L1TrackJetProducer::L1TrackJetProducer(const ParameterSet &iConfig)
    : trkZMax_(iConfig.getParameter<double>("trk_zMax")),
      trkPtMax_(iConfig.getParameter<double>("trk_ptMax")),
      trkEtaMax_(iConfig.getParameter<double>("trk_etaMax")),
      lowpTJetMinTrackMultiplicity_(iConfig.getParameter<int>("lowpTJetMinTrackMultiplicity")),
      lowpTJetThreshold_(iConfig.getParameter<double>("lowpTJetThreshold")),
      highpTJetMinTrackMultiplicity_(iConfig.getParameter<int>("highpTJetMinTrackMultiplicity")),
      highpTJetThreshold_(iConfig.getParameter<double>("highpTJetThreshold")),
      zBins_(iConfig.getParameter<int>("zBins")),
      etaBins_(iConfig.getParameter<int>("etaBins")),
      phiBins_(iConfig.getParameter<int>("phiBins")),
      minTrkJetpT_(iConfig.getParameter<double>("minTrkJetpT")),
      displaced_(iConfig.getParameter<bool>("displaced")),
      d0CutNStubs4_(iConfig.getParameter<double>("d0_cutNStubs4")),
      d0CutNStubs5_(iConfig.getParameter<double>("d0_cutNStubs5")),
      nDisplacedTracks_(iConfig.getParameter<int>("nDisplacedTracks")),
      trackToken_(consumes<L1TTTrackRefCollectionType>(iConfig.getParameter<InputTag>("L1TrackInputTag"))) {
  zStep_ = 2.0 * trkZMax_ / (zBins_ + 1);  // added +1 in denom
  etaStep_ = 2.0 * trkEtaMax_ / etaBins_;  //etaStep is the width of an etabin
  phiStep_ = 2 * M_PI / phiBins_;          

  if (displaced_)
    produces<TkJetCollection>("L1TrackJetsExtended");
  else
    produces<TkJetCollection>("L1TrackJets");
}

void L1TrackJetProducer::produce(Event &iEvent, const EventSetup &iSetup) {
  unique_ptr<TkJetCollection> L1TrackJetProducer(new TkJetCollection);

  // L1 tracks
  edm::Handle<L1TTTrackRefCollectionType> TTTrackHandle;
  iEvent.getByToken(trackToken_, TTTrackHandle);

  L1TrkPtrs_.clear();

  // track selection
  for (unsigned int this_l1track = 0; this_l1track < TTTrackHandle->size(); this_l1track++) {
    edm::Ptr<L1TTTrackType> trkPtr(TTTrackHandle, this_l1track);
    L1TrkPtrs_.push_back(trkPtr);
  }

  // if no tracks pass selection return empty containers
  if (L1TrkPtrs_.empty()) {
    if (displaced_)
      iEvent.put(std::move(L1TrackJetProducer), "L1TrackJetsExtended");
    else
      iEvent.put(std::move(L1TrackJetProducer), "L1TrackJets");
    return;
  }

  MaxZBin mzb;
  mzb.znum = -1;
  mzb.nclust = -1;
  mzb.ht = -1;

  // create 2D grid of eta phi bins
  EtaPhiBin epbins_default[phiBins_][etaBins_];
  float phi = -1.0 * M_PI;
  for (int i = 0; i < phiBins_; ++i) {
    float eta = -1.0 * trkEtaMax_;
    for (int j = 0; j < etaBins_; ++j) {
      epbins_default[i][j].phi = (phi + (phi + phiStep_)) / 2.0;
      epbins_default[i][j].eta = (eta + (eta + etaStep_)) / 2.0;
      eta += etaStep_;
    }  // for each etabin
    phi += phiStep_;
  }  // for each phibin (finished creating bins)

  // create z-bins (might be useful for displaced if we run w/o dz cut)
  std::vector<float> zmins, zmaxs;
  for (int zbin = 0; zbin < zBins_; zbin++) {
    zmins.push_back(-1.0 * trkZMax_ + zStep_ * zbin);
    zmaxs.push_back(-1.0 * trkZMax_ + zStep_ * zbin + zStep_ * 2);
  }

  // create vectors of clusters
  std::vector<std::vector<EtaPhiBin>> L1clusters;
  L1clusters.reserve(phiBins_);
  std::vector<EtaPhiBin> L2clusters;

  // default (empty) grid
  for (int i = 0; i < phiBins_; ++i) {
    for (int j = 0; j < etaBins_; ++j) {
      epbins_default[i][j].pTtot = 0;
      epbins_default[i][j].used = false;
      epbins_default[i][j].ntracks = 0;
      epbins_default[i][j].nxtracks = 0;
      epbins_default[i][j].trackidx.clear();
    }
  }

  for (unsigned int zbin = 0; zbin < zmins.size(); ++zbin) {
    // initialize grid
    float zmin = zmins[zbin];
    float zmax = zmaxs[zbin];
    EtaPhiBin epbins[phiBins_][etaBins_];
    std::copy(&epbins_default[0][0], &epbins_default[0][0] + phiBins_ * etaBins_, &epbins[0][0]);

    //clear cluster containers
    L1clusters.clear();
    L2clusters.clear();

    // fill grid with tracks
    for (unsigned int k = 0; k < L1TrkPtrs_.size(); ++k) {
      float trkZ = L1TrkPtrs_[k]->z0();
      if (zmax < trkZ)
        continue;
      if (zmin > trkZ)
        continue;
      if (zbin == 0 && zmin == trkZ)
        continue;
      float trkpt = L1TrkPtrs_[k]->momentum().perp();
      float trketa = L1TrkPtrs_[k]->momentum().eta();
      float trkphi = L1TrkPtrs_[k]->momentum().phi();
      float trkd0 = L1TrkPtrs_[k]->d0();
      int trknstubs = (int)L1TrkPtrs_[k]->getStubRefs().size();
      for (int i = 0; i < phiBins_; ++i) {
        for (int j = 0; j < etaBins_; ++j) {
          float eta_min = epbins[i][j].eta - etaStep_ / 2.0;  //eta min
          float eta_max = epbins[i][j].eta + etaStep_ / 2.0;  //eta max
          float phi_min = epbins[i][j].phi - phiStep_ / 2.0;  //phi min
          float phi_max = epbins[i][j].phi + phiStep_ / 2.0;  //phi max

          if ((trketa < eta_min) || (trketa > eta_max) || (trkphi < phi_min) || (trkphi > phi_max))
            continue;

          if (trkpt < trkPtMax_)
            epbins[i][j].pTtot += trkpt;
          else
            epbins[i][j].pTtot += trkPtMax_;
          if ((std::abs(trkd0) > d0CutNStubs5_ && trknstubs >= 5 && d0CutNStubs5_ >= 0) ||
              (trknstubs == 4 && std::abs(trkd0) > d0CutNStubs4_ && d0CutNStubs4_ >= 0))
            epbins[i][j].nxtracks += 1;
          epbins[i][j].trackidx.push_back(k);
          ++epbins[i][j].ntracks;
        }  // for each etabin
      }    // for each phibin
    }      //end loop over tracks

    // cluster tracks in eta (first layer) using grid
    for (int phibin = 0; phibin < phiBins_; ++phibin) {
      L1clusters.push_back(L1_clustering<EtaPhiBin, float, float, float>(epbins[phibin], etaBins_, etaStep_));
    }

    // second layer clustering in phi for using eta clusters
    L2clusters = L2_clustering<EtaPhiBin, float, float, float>(L1clusters, phiBins_, phiStep_, etaStep_);

    // sum all cluster pTs in this zbin to find max
    float sum_pt = 0;
    for (unsigned int k = 0; k < L2clusters.size(); ++k) {
      if (L2clusters[k].pTtot > lowpTJetThreshold_ && L2clusters[k].ntracks < lowpTJetMinTrackMultiplicity_)
        continue;
      if (L2clusters[k].pTtot > highpTJetThreshold_ && L2clusters[k].ntracks < highpTJetMinTrackMultiplicity_)
        continue;
      if (L2clusters[k].pTtot > minTrkJetpT_)
        sum_pt += L2clusters[k].pTtot;
    }

    if (sum_pt < mzb.ht)
      continue;

    // if ht is larger than previous max, this is the new vertex zbin
    mzb.ht = sum_pt;
    mzb.znum = zbin;
    mzb.clusters = L2clusters;
    mzb.nclust = L2clusters.size();
    mzb.zbincenter = (zmin + zmax) / 2.0;
  }  //zbin loop

  // output
  vector<Ptr<L1TTTrackType>> L1TrackAssocJet;
  for (unsigned int j = 0; j < mzb.clusters.size(); ++j) {
    float jetEta = mzb.clusters[j].eta;
    float jetPhi = mzb.clusters[j].phi;
    float jetPt = mzb.clusters[j].pTtot;
    float jetPx = jetPt * cos(jetPhi);
    float jetPy = jetPt * sin(jetPhi);
    float jetPz = jetPt * sinh(jetEta);
    float jetP = jetPt * cosh(jetEta);
    int totalDisptrk = mzb.clusters[j].nxtracks;
    bool isDispJet = (totalDisptrk >= nDisplacedTracks_);

    math::XYZTLorentzVector jetP4(jetPx, jetPy, jetPz, jetP);
    L1TrackAssocJet.clear();
    for (unsigned int itrk = 0; itrk < mzb.clusters[j].trackidx.size(); itrk++)
      L1TrackAssocJet.push_back(L1TrkPtrs_[mzb.clusters[j].trackidx[itrk]]);

    TkJet trkJet(jetP4, L1TrackAssocJet, mzb.zbincenter, mzb.clusters[j].ntracks, 0, totalDisptrk, 0, isDispJet);

    L1TrackJetProducer->push_back(trkJet);
  }

  std::sort(L1TrackJetProducer->begin(), L1TrackJetProducer->end(), [](auto &a, auto &b) { return a.pt() > b.pt(); });
  if (displaced_)
    iEvent.put(std::move(L1TrackJetProducer), "L1TrackJetsExtended");
  else
    iEvent.put(std::move(L1TrackJetProducer), "L1TrackJets");
}

void L1TrackJetProducer::fillDescriptions(ConfigurationDescriptions &descriptions) {
  ParameterSetDescription desc;
  desc.add<edm::InputTag>(
      "L1TrackInputTag", edm::InputTag("l1tTrackVertexAssociationProducerForJets", "Level1TTTracksSelectedAssociated"));
  desc.add<double>("trk_zMax", 15.0);
  desc.add<double>("trk_ptMax", 200.0);
  desc.add<double>("trk_etaMax", 2.4);
  desc.add<double>("minTrkJetpT", -1.0);
  desc.add<int>("etaBins", 24);
  desc.add<int>("phiBins", 27);
  desc.add<int>("zBins", 1);
  desc.add<double>("d0_cutNStubs4", -1);
  desc.add<double>("d0_cutNStubs5", -1);
  desc.add<int>("lowpTJetMinTrackMultiplicity", 2);
  desc.add<double>("lowpTJetThreshold", 50.0);
  desc.add<int>("highpTJetMinTrackMultiplicity", 3);
  desc.add<double>("highpTJetThreshold", 100.0);
  desc.add<bool>("displaced", false);
  desc.add<int>("nDisplacedTracks", 2);
  descriptions.add("l1tTrackJets", desc);
}

//define this as a plug-in
DEFINE_FWK_MODULE(L1TrackJetProducer);