SeedTransformer.cc

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/*
 *  See header file for a description of this class.
 *
 *  \author D. Trocino - University and INFN Torino
 */

#include "TrackingTools/TrackRefitter/interface/SeedTransformer.h"

// System include files
// #include <memory>
// #include <Riostream.h>

// Framework
#include "FWCore/Framework/interface/MakerMacros.h"
#include "FWCore/Framework/interface/Frameworkfwd.h"
#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Framework/interface/EventSetup.h"
#include "FWCore/Framework/interface/ESHandle.h"
#include "FWCore/Framework/interface/ConsumesCollector.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"

// Services and Tools

// Geometry and Magnetic field
#include "MagneticField/Records/interface/IdealMagneticFieldRecord.h"
#include "Geometry/Records/interface/GlobalTrackingGeometryRecord.h"
#include "Geometry/CommonDetUnit/interface/GeomDet.h"
#include "Geometry/CommonDetUnit/interface/GlobalTrackingGeometry.h"

// Other include files
#include "TrackingTools/Records/interface/TransientRecHitRecord.h"
#include "TrackingTools/TransientTrackingRecHit/interface/TransientTrackingRecHitBuilder.h"
#include "TrackingTools/TrajectoryState/interface/TrajectoryStateOnSurface.h"
#include "TrackingTools/TrajectoryState/interface/TrajectoryStateTransform.h"
#include "TrackingTools/Records/interface/TrackingComponentsRecord.h"
#include "TrackingTools/TrackFitters/interface/TrajectoryFitter.h"
#include "TrackingTools/PatternTools/interface/Trajectory.h"
#include "TrackingTools/GeomPropagators/interface/Propagator.h"

#include "RecoMuon/TransientTrackingRecHit/interface/MuonTransientTrackingRecHitBreaker.h"

using namespace std;
using namespace edm;
using namespace reco;

SeedTransformer::SeedTransformer(const ParameterSet& iConfig, ConsumesCollector iC) {
  LogTrace("Reco|TrackingTools|SeedTransformer") << "SeedTransformer constructor called." << endl << endl;

  theTrackingGeometryToken = iC.esConsumes();
  theMagneticFieldToken = iC.esConsumes();
  auto fitterName = iConfig.getParameter<string>("Fitter");
  theFitterToken = iC.esConsumes(edm::ESInputTag("", fitterName));
  auto muonRecHitBuilderName = iConfig.getParameter<string>("MuonRecHitBuilder");
  theMuonRecHitBuilderToken = iC.esConsumes(edm::ESInputTag("", muonRecHitBuilderName));
  auto propagatorName = iConfig.getParameter<string>("Propagator");
  thePropagatorToken = iC.esConsumes(edm::ESInputTag("", propagatorName));

  nMinRecHits = iConfig.getParameter<unsigned int>("NMinRecHits");
  errorRescale = iConfig.getParameter<double>("RescaleError");
  useSubRecHits = iConfig.getParameter<bool>("UseSubRecHits");
}

SeedTransformer::~SeedTransformer() {
  LogTrace("Reco|TrackingTools|SeedTransformer") << "SeedTransformer destructor called." << endl << endl;
}

void SeedTransformer::setServices(const EventSetup& iSetup) {
  theTrackingGeometry = &iSetup.getData(theTrackingGeometryToken);
  theMagneticField = &iSetup.getData(theMagneticFieldToken);
  theFitter = &iSetup.getData(theFitterToken);
  theMuonRecHitBuilder = &iSetup.getData(theMuonRecHitBuilderToken);
  thePropagator = &iSetup.getData(thePropagatorToken);
}

vector<Trajectory> SeedTransformer::seedTransform(const TrajectorySeed& aSeed) const {
  const string metname = "Reco|TrackingTools|SeedTransformer";

  LogTrace(metname) << " Number of valid RecHits:      " << aSeed.nHits() << endl;

  if (aSeed.nHits() < nMinRecHits) {
    LogTrace(metname) << "    --- Too few RecHits, no refit performed! ---" << endl;
    return vector<Trajectory>();
  }

  TrajectoryStateOnSurface aTSOS(seedTransientState(aSeed));

  // Rescale errors before refit, not to bias the result
  aTSOS.rescaleError(errorRescale);

  vector<TransientTrackingRecHit::ConstRecHitPointer> recHits;

  for (auto const& recHit : aSeed.recHits()) {
    if (recHit.isValid()) {
      TransientTrackingRecHit::ConstRecHitPointer ttrh(theMuonRecHitBuilder->build(&recHit));

      if (useSubRecHits) {
        TransientTrackingRecHit::ConstRecHitContainer subHits =
            MuonTransientTrackingRecHitBreaker::breakInSubRecHits(ttrh, 2);
        copy(subHits.begin(), subHits.end(), back_inserter(recHits));
      } else {
        recHits.push_back(ttrh);
      }
    }
  }

  TrajectoryStateOnSurface aInitTSOS = thePropagator->propagate(aTSOS, recHits.front()->det()->surface());

  if (!aInitTSOS.isValid()) {
    LogTrace(metname) << "    --- Initial state for refit not valid! ---" << endl;
    return vector<Trajectory>();
  }

  vector<Trajectory> refittedSeed = theFitter->fit(aSeed, recHits, aInitTSOS);

  if (refittedSeed.empty()) {
    LogTrace(metname) << "    --- Seed fit failed! ---" << endl;
    return vector<Trajectory>();
  }

  else if (!refittedSeed.front().isValid()) {
    LogTrace(metname) << "    --- Seed fitted, but trajectory not valid! ---" << endl;
    return vector<Trajectory>();
  }

  else
    LogTrace(metname) << "    +++ Seed fit succeded! +++" << endl;

  return refittedSeed;
}

TrajectoryStateOnSurface SeedTransformer::seedTransientState(const TrajectorySeed& tmpSeed) const {
  PTrajectoryStateOnDet tmpTSOD = tmpSeed.startingState();
  DetId tmpDetId(tmpTSOD.detId());
  const GeomDet* tmpGeomDet = theTrackingGeometry->idToDet(tmpDetId);

  TrajectoryStateOnSurface tmpTSOS =
      trajectoryStateTransform::transientState(tmpTSOD, &(tmpGeomDet->surface()), &(*theMagneticField));

  return tmpTSOS;
}