HITrackingRegionForPrimaryVtxProducer.h

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#ifndef RecoHI_HiTracking_HITrackingRegionForPrimaryVtxProducer_H 
#define RecoHI_HiTracking_HITrackingRegionForPrimaryVtxProducer _H

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

#include "RecoTracker/TkTrackingRegions/interface/TrackingRegionProducer.h"
#include "RecoTracker/TkTrackingRegions/interface/GlobalTrackingRegion.h"
#include "RecoTracker/TkTrackingRegions/interface/RectangularEtaPhiTrackingRegion.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Framework/interface/ConsumesCollector.h"

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

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

#include "DataFormats/TrackerCommon/interface/TrackerTopology.h"
#include "Geometry/Records/interface/TrackerTopologyRcd.h"
#include "DataFormats/Common/interface/DetSetAlgorithm.h"

#include "DataFormats/Common/interface/DetSetVector.h"    
#include "DataFormats/TrackerRecHit2D/interface/SiPixelRecHitCollection.h"

#include "TMath.h"

class HITrackingRegionForPrimaryVtxProducer : public TrackingRegionProducer {
  
 public:
  
  HITrackingRegionForPrimaryVtxProducer(const edm::ParameterSet& cfg, edm::ConsumesCollector && iC) { 
    
    edm::ParameterSet regionPSet = cfg.getParameter<edm::ParameterSet>("RegionPSet");
    thePtMin            = regionPSet.getParameter<double>("ptMin");
    theOriginRadius     = regionPSet.getParameter<double>("originRadius");
    theNSigmaZ          = regionPSet.getParameter<double>("nSigmaZ");
    theBeamSpotTag      = regionPSet.getParameter<edm::InputTag>("beamSpot");
    theBeamSpotToken    = iC.consumes<reco::BeamSpot>(theBeamSpotTag); 
    thePrecise          = regionPSet.getParameter<bool>("precise"); 
    theSiPixelRecHits   = regionPSet.getParameter<edm::InputTag>("siPixelRecHits");
    theSiPixelRecHitsToken = iC.consumes<SiPixelRecHitCollection> (theSiPixelRecHits);     
    doVariablePtMin     = regionPSet.getParameter<bool>("doVariablePtMin"); 
    double xDir         = regionPSet.getParameter<double>("directionXCoord");
    double yDir         = regionPSet.getParameter<double>("directionYCoord");
    double zDir         = regionPSet.getParameter<double>("directionZCoord");
    theDirection = GlobalVector(xDir, yDir, zDir);

    // for using vertex instead of beamspot
    theSigmaZVertex     = regionPSet.getParameter<double>("sigmaZVertex");
    theFixedError       = regionPSet.getParameter<double>("fixedError");
    theUseFoundVertices = regionPSet.getParameter<bool>("useFoundVertices");
    theUseFixedError    = regionPSet.getParameter<bool>("useFixedError");
    vertexCollName      = regionPSet.getParameter<edm::InputTag>("VertexCollection");
    vertexCollToken     = iC.consumes<reco::VertexCollection>(vertexCollName);
  }   
  
  ~HITrackingRegionForPrimaryVtxProducer() override{}

  static void fillDescriptions(edm::ConfigurationDescriptions& descriptions) {
    edm::ParameterSetDescription desc;

    desc.add<double>("ptMin", 0.7);
    desc.add<bool>("doVariablePtMin", true);
    desc.add<double>("originRadius", 0.2);
    desc.add<double>("nSigmaZ", 3.0);
    desc.add<edm::InputTag>("beamSpot", edm::InputTag("offlineBeamSpot"));
    desc.add<bool>("precise", true);
    desc.add<bool>("useMultipleScattering", false);
    desc.add<bool>("useFakeVertices", false);
    desc.add<edm::InputTag>("siPixelRecHits", edm::InputTag("siPixelRecHits"));
    desc.add<double>("directionXCoord", 1.0);
    desc.add<double>("directionYCoord", 1.0);
    desc.add<double>("directionZCoord", 0.0);
    desc.add<bool>("useFoundVertices", true);
    desc.add<edm::InputTag>("VertexCollection", edm::InputTag("hiPixelClusterVertex"));
    desc.add<bool>("useFixedError", true);
    desc.add<double>("fixedError", 3.0);
    desc.add<double>("sigmaZVertex", 3.0);

    // Only for backwards-compatibility
    edm::ParameterSetDescription descRegion;
    descRegion.add<edm::ParameterSetDescription>("RegionPSet", desc);

    descriptions.add("hiTrackingRegionFromClusterVtx", descRegion);
  }
  
  int estimateMultiplicity
    (const edm::Event& ev, const edm::EventSetup& es) const
    {
      //rechits
      edm::Handle<SiPixelRecHitCollection> recHitColl;
      ev.getByToken(theSiPixelRecHitsToken, recHitColl);

      edm::ESHandle<TrackerTopology> httopo;
      es.get<TrackerTopologyRcd>().get(httopo);
      
      std::vector<const TrackingRecHit*> theChosenHits;      
      edmNew::copyDetSetRange(*recHitColl,theChosenHits, httopo->pxbDetIdLayerComparator(1));
      return theChosenHits.size();   
      
    }
  
  std::vector<std::unique_ptr<TrackingRegion> > regions(const edm::Event& ev, const edm::EventSetup& es) const override {
    
    int estMult = estimateMultiplicity(ev, es);
    
    // from MC relating first layer pixel hits to "findable" sim tracks with pt>1 GeV
    float cc = -38.6447;
    float bb = 0.0581765;
    float aa = 1.34306e-06;

    float estTracks = aa*estMult*estMult+bb*estMult+cc;
    
    LogTrace("heavyIonHLTVertexing")<<"[HIVertexing]";
    LogTrace("heavyIonHLTVertexing")<<" [HIVertexing: hits in the 1. layer:" << estMult << "]";
    LogTrace("heavyIonHLTVertexing")<<" [HIVertexing: estimated number of tracks:" << estTracks << "]";
    
    float regTracking = 60.;  //if we have more tracks -> regional tracking
    float etaB = 10.;
    float phiB = TMath::Pi()/2.;
    
    float decEta = estTracks/90.;
    etaB = 2.5/decEta;
    
    if(estTracks>regTracking) {
      LogTrace("heavyIonHLTVertexing")<<" [HIVertexing: Regional Tracking]";
      LogTrace("heavyIonHLTVertexing")<<"  [Regional Tracking: eta range: -" << etaB << ", "<< etaB <<"]";
      LogTrace("heavyIonHLTVertexing")<<"  [Regional Tracking: phi range: -" << phiB << ", "<< phiB <<"]";
      LogTrace("heavyIonHLTVertexing")<<"  [Regional Tracking: factor of decrease: " << decEta*2. << "]";  // 2:from phi
    }
    
    float minpt = thePtMin;
    float varPtCutoff = 1500; //cutoff
    if(doVariablePtMin && estMult < varPtCutoff) {
      minpt = 0.075;
      if(estMult > 0) minpt += estMult * (thePtMin - 0.075)/varPtCutoff; // lower ptMin linearly with pixel hit multiplicity
    }
    
    // tracking region selection
    std::vector<std::unique_ptr<TrackingRegion> > result;
    double halflength;
    GlobalPoint origin;
    edm::Handle<reco::BeamSpot> bsHandle;
    ev.getByToken(theBeamSpotToken, bsHandle);
    if(bsHandle.isValid()) {
      const reco::BeamSpot & bs = *bsHandle; 
      origin=GlobalPoint(bs.x0(), bs.y0(), bs.z0()); 
      halflength=theNSigmaZ*bs.sigmaZ();
      
    if(theUseFoundVertices)
    {
      edm::Handle<reco::VertexCollection> vertexCollection;
      ev.getByToken(vertexCollToken,vertexCollection);

      for(reco::VertexCollection::const_iterator iV=vertexCollection->begin(); 
      iV != vertexCollection->end() ; iV++) {
          if (iV->isFake() || !iV->isValid()) continue;
      origin     = GlobalPoint(bs.x0(),bs.y0(),iV->z());
      halflength = (theUseFixedError ? theFixedError : (iV->zError())*theSigmaZVertex); 
      }
    }

      if(estTracks>regTracking) {  // regional tracking
        result.push_back( 
          std::make_unique<RectangularEtaPhiTrackingRegion>(theDirection, origin, thePtMin, theOriginRadius, halflength, etaB, phiB, RectangularEtaPhiTrackingRegion::UseMeasurementTracker::kNever, thePrecise) );
      }
      else {                       // global tracking
        LogTrace("heavyIonHLTVertexing")<<" [HIVertexing: Global Tracking]";
        result.push_back( 
          std::make_unique<GlobalTrackingRegion>(minpt, origin, theOriginRadius, halflength, thePrecise) );
      }
    } 
    return result;
  }
  
 private:
  double thePtMin; 
  double theOriginRadius; 
  double theNSigmaZ;
  edm::InputTag theBeamSpotTag; 
  edm::EDGetTokenT<reco::BeamSpot> theBeamSpotToken;
  bool thePrecise;
  GlobalVector theDirection;
  edm::InputTag theSiPixelRecHits;
  edm::EDGetTokenT<SiPixelRecHitCollection> theSiPixelRecHitsToken;
  bool doVariablePtMin;

  double theSigmaZVertex;
  double theFixedError;  
  bool theUseFoundVertices;
  bool theUseFixedError;
  edm::InputTag vertexCollName;
  edm::EDGetTokenT<reco::VertexCollection> vertexCollToken;


};

#endif