HIProtoTrackSelector.h

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#ifndef HIProtoTrackSelection_h
#define HIProtoTrackSelection_h

#include "FWCore/Framework/interface/ConsumesCollector.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/Framework/interface/Event.h"

#include "DataFormats/TrackReco/interface/TrackFwd.h"
#include "DataFormats/TrackReco/interface/Track.h"

#include "DataFormats/VertexReco/interface/Vertex.h"
#include "DataFormats/VertexReco/interface/VertexFwd.h"

#include "DataFormats/BeamSpot/interface/BeamSpot.h"
#include "FWCore/Utilities/interface/InputTag.h"

#include "FWCore/MessageLogger/interface/MessageLogger.h"

#include <algorithm>
#include <iostream>

class HIProtoTrackSelector
{

 public:
  // input collection type
  typedef reco::TrackCollection collection;

  // output collection type
  typedef std::vector<const reco::Track *> container;

  // iterator over result collection type.
  typedef container::const_iterator const_iterator;

  // constructor from parameter set configurability
  HIProtoTrackSelector(const edm::ParameterSet & iConfig, edm::ConsumesCollector && iC) :
    vertexCollection_(iConfig.getParameter<edm::InputTag>("VertexCollection")),
    vertexCollectionToken_(iC.consumes<reco::VertexCollection>(vertexCollection_)),
    beamSpot_(iConfig.getParameter<edm::InputTag>("beamSpotLabel")),
    beamSpotToken_(iC.consumes<reco::BeamSpot>(beamSpot_)),
    ptMin_(iConfig.getParameter<double>("ptMin")),
    nSigmaZ_(iConfig.getParameter<double>("nSigmaZ")),
    minZCut_(iConfig.getParameter<double>("minZCut")),
    maxD0Significance_(iConfig.getParameter<double>("maxD0Significance"))
    {};

  // select object from a collection and possibly event content
  void select( edm::Handle<reco::TrackCollection>& TCH, const edm::Event & iEvent, const edm::EventSetup & iSetup)
    {
      selected_.clear();

      const collection & c = *(TCH.product());

      // Get fast reco vertex
      edm::Handle<reco::VertexCollection> vc;
      iEvent.getByToken(vertexCollectionToken_, vc);
      const reco::VertexCollection * vertices = vc.product();

      math::XYZPoint vtxPoint(0.0,0.0,0.0);
      double vzErr =0.0;

      if(!vertices->empty()) {
    vtxPoint=vertices->begin()->position();
    vzErr=vertices->begin()->zError();
    edm::LogInfo("HeavyIonVertexing") << "Select prototracks compatible with median vertex"
                     << "\n   vz = " << vtxPoint.Z()
                     << "\n   " << nSigmaZ_ << " vz sigmas = " << vzErr*nSigmaZ_
                     << "\n   cut at = " << std::max(vzErr*nSigmaZ_,minZCut_);
      }
      // Supress this warning, since events w/ no vertex are expected
      //else {
    //edm::LogError("HeavyIonVertexing") << "No vertex found in collection '" << vertexCollection_ << "'";
      //}

      // Get beamspot
      reco::BeamSpot beamSpot;
      edm::Handle<reco::BeamSpot> beamSpotHandle;
      iEvent.getByToken(beamSpotToken_, beamSpotHandle);

      math::XYZPoint bsPoint(0.0,0.0,0.0);
      double bsWidth = 0.0;

      if ( beamSpotHandle.isValid() ) {
    beamSpot = *beamSpotHandle;
    bsPoint = beamSpot.position();
    bsWidth = sqrt(beamSpot.BeamWidthX()*beamSpot.BeamWidthY());
    edm::LogInfo("HeavyIonVertexing") << "Select prototracks compatible with beamspot"
                     << "\n   (x,y,z) = (" << bsPoint.X() << "," << bsPoint.Y() << "," << bsPoint.Z() << ")"
                     << "\n   width = " << bsWidth
                     << "\n   cut at d0/d0sigma = " << maxD0Significance_;
      } else {
    edm::LogError("HeavyIonVertexing") << "No beam spot available from '" << beamSpot_ << "\n";
      }


      // Do selection
      int nSelected=0;
      int nRejected=0;
      double d0=0.0;
      double d0sigma=0.0;
      for (reco::TrackCollection::const_iterator trk = c.begin(); trk != c.end(); ++ trk)
    {

      d0 = -1.*trk->dxy(bsPoint);
      d0sigma = sqrt(trk->d0Error()*trk->d0Error() + bsWidth*bsWidth);
      if ( trk->pt() > ptMin_ // keep only tracks above ptMin
           && fabs(d0/d0sigma) < maxD0Significance_ // keep only tracks with D0 significance less than cut
           && fabs(trk->dz(vtxPoint)) <  std::max(vzErr*nSigmaZ_,minZCut_) // within minZCut, nSigmaZ of fast vertex
           )
      {
        nSelected++;
        selected_.push_back( & * trk );
      }
      else
        nRejected++;
    }

      edm::LogInfo("HeavyIonVertexing") << "selected " << nSelected << " prototracks out of " << nRejected+nSelected << "\n";

    }

  // iterators over selected objects: collection begin
  const_iterator begin() const { return selected_.begin(); }

  // iterators over selected objects: collection end
  const_iterator end() const { return selected_.end(); }

  // true if no object has been selected
  size_t size() const { return selected_.size(); }


 private:
  container selected_;
  edm::InputTag vertexCollection_;
  edm::EDGetTokenT<reco::VertexCollection> vertexCollectionToken_;
  edm::InputTag beamSpot_;
  edm::EDGetTokenT<reco::BeamSpot> beamSpotToken_;
  double ptMin_;
  double nSigmaZ_;
  double minZCut_;
  double maxD0Significance_;

};


#endif