TrackClusterSplitter.cc

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#include "FWCore/Framework/interface/Frameworkfwd.h"
#include "FWCore/Framework/interface/stream/EDProducer.h"
#include "FWCore/Framework/interface/Event.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/Utilities/interface/InputTag.h"

#include "DataFormats/Common/interface/Handle.h"
#include "FWCore/Framework/interface/ESHandle.h"
#include "DataFormats/SiStripCluster/interface/SiStripCluster.h"
#include "DataFormats/SiPixelCluster/interface/SiPixelCluster.h"
#include "DataFormats/TrackerRecHit2D/interface/SiStripRecHit2D.h"
#include "DataFormats/TrackerRecHit2D/interface/SiStripRecHit1D.h"
#include "DataFormats/TrackerRecHit2D/interface/SiPixelRecHit.h"
#include "DataFormats/Common/interface/DetSetVectorNew.h"

#include "DataFormats/TrackReco/interface/Track.h"
#include "DataFormats/VertexReco/interface/Vertex.h"

#include "TrackingTools/PatternTools/interface/Trajectory.h"
#include "TrackingTools/PatternTools/interface/TrajTrackAssociation.h"
#include "TrackingTools/TrajectoryState/interface/TrajectoryStateOnSurface.h"
#include "TrackingTools/GeomPropagators/interface/Propagator.h"
#include "TrackingTools/TrajectoryState/interface/TrajectoryStateTransform.h"
#include "MagneticField/Records/interface/IdealMagneticFieldRecord.h"
#include "MagneticField/Engine/interface/MagneticField.h"
#include "TrackingTools/Records/interface/TrackingComponentsRecord.h"
#include "Geometry/CommonDetUnit/interface/GlobalTrackingGeometry.h"
#include "Geometry/Records/interface/GlobalTrackingGeometryRecord.h"

//added for my stuff H.S.
#include "SimDataFormats/TrackerDigiSimLink/interface/PixelDigiSimLink.h"
#include "DataFormats/SiPixelDigi/interface/PixelDigi.h"
#include "DataFormats/SiPixelCluster/interface/SiPixelCluster.h"

// gavril: the template header files
#include "RecoLocalTracker/SiPixelRecHits/interface/SiPixelTemplate.h"
#include "RecoLocalTracker/SiPixelRecHits/interface/SiPixelTemplate2D.h"
#include "RecoLocalTracker/SiPixelRecHits/interface/SiPixelTemplateSplit.h"
#include "RecoLocalTracker/SiPixelRecHits/interface/SiPixelTemplateDefs.h"
#include "RecoLocalTracker/SiPixelRecHits/interface/SiPixelTemplateReco.h"

#include "RecoLocalTracker/SiStripRecHitConverter/interface/SiStripTemplate.h"
#include "RecoLocalTracker/SiStripRecHitConverter/interface/SiStripTemplateSplit.h"
#include "RecoLocalTracker/SiStripRecHitConverter/interface/SiStripTemplateDefs.h"
#include "RecoLocalTracker/SiStripRecHitConverter/interface/SiStripTemplateReco.h"

#include "Geometry/TrackerGeometryBuilder/interface/RectangularPixelTopology.h"
#include "Geometry/TrackerGeometryBuilder/interface/PixelGeomDetUnit.h"
#include "Geometry/TrackerGeometryBuilder/interface/StripGeomDetUnit.h"
#include "DataFormats/SiStripDetId/interface/SiStripDetId.h"

// for strip sim splitting
#include "SimDataFormats/TrackerDigiSimLink/interface/StripDigiSimLink.h"
#include "SimTracker/TrackerHitAssociation/interface/TrackerHitAssociator.h"

#include <boost/range.hpp>
#include <boost/foreach.hpp>
#include "boost/multi_array.hpp"

#include <iostream>
#include <memory>
using namespace std;

class TrackClusterSplitter : public edm::stream::EDProducer<>
{

public:
  TrackClusterSplitter(const edm::ParameterSet& iConfig) ;
  ~TrackClusterSplitter() override ;
  void produce(edm::Event &iEvent, const edm::EventSetup &iSetup) override ;
  
private:
  edm::EDGetTokenT<edmNew::DetSetVector<SiPixelCluster> > pixelClusters_;
  edm::EDGetTokenT<edmNew::DetSetVector<SiStripCluster> > stripClusters_;

  bool simSplitPixel_;
  bool simSplitStrip_;
  bool tmpSplitPixel_;
  bool tmpSplitStrip_;

  // Template splitting needs to know the track direction.
  // We can use either straight tracks, pixel tracks of fully reconstructed track. 
  // Straight tracks go from the first pixel verterx  in the pixel vertex collection 
  // to the cluster center of charge (we use pixel vertices because track vertices are 
  // are not available at this point) 
  // If we set useStraightTracks_ = True, then straight tracks are used
  bool useStraightTracks_;
  
  // If straight track approximation is not used (useStraightTracks_ = False), then, one can use either fully 
  // reconstructed tracks (useTrajectories_ = True) or pixel tracks ((useTrajectories_ = False). 
  // The use of either straight or fully reconstructed tracks give very similar performance. Use straight tracks 
  // by default because it's faster and less involved. Pixel tracks DO NOT work.
  bool useTrajectories_; 

  // These are either "generalTracks", if useTrajectories_ = True, or "pixelTracks" if  useTrajectories_ = False
  edm::EDGetTokenT<TrajTrackAssociationCollection > trajTrackAssociations_;
  edm::EDGetTokenT<std::vector<reco::Track> > tracks_;

  // This is the pixel primary vertex collection
  edm::EDGetTokenT<std::vector<reco::Vertex> > vertices_;
  
  edm::EDGetTokenT< edm::DetSetVector<PixelDigiSimLink> > pixeldigisimlinkToken;
  edm::EDGetTokenT< edm::DetSetVector<StripDigiSimLink> > stripdigisimlinkToken;

  // gavril : what is this for ?
  std::string propagatorName_;
  edm::ESHandle<MagneticField>          magfield_;
  edm::ESHandle<Propagator>             propagator_;
  edm::ESHandle<GlobalTrackingGeometry> geometry_;
  
  // This is needed if we want to to sim/truth pixel splitting
  edm::Handle< edm::DetSetVector<PixelDigiSimLink> > pixeldigisimlink;
  
   // This is needed if we want to to sim/truth strip splitting
  edm::Handle< edm::DetSetVector<StripDigiSimLink> > stripdigisimlink;
  

  // Template declarations
  // Pixel templates
  std::vector< SiPixelTemplateStore > thePixelTemp_;
  std::vector< SiPixelTemplateStore2D > thePixelTemp2D_;
  // Strip template
  std::vector< SiStripTemplateStore > theStripTemp_;

  // A pointer to a track and a state on the detector
  struct TrackAndState 
  {
    TrackAndState(const reco::Track *aTrack, TrajectoryStateOnSurface aState) :  
      track(aTrack), state(aState) {}
    const reco::Track*      track;
    TrajectoryStateOnSurface state; 
  };
  
  // A pointer to a cluster and a list of tracks on it
  template<typename Cluster>
  struct ClusterWithTracks 
  {
    ClusterWithTracks(const Cluster &c) : cluster(&c) {}
    const Cluster* cluster;
    std::vector<TrackAndState> tracks;
  };

  typedef ClusterWithTracks<SiPixelCluster> SiPixelClusterWithTracks;
  typedef ClusterWithTracks<SiStripCluster> SiStripClusterWithTracks;


  // a subset of a vector, but with vector-like interface.
  typedef boost::sub_range<std::vector<SiPixelClusterWithTracks> > SiPixelClustersWithTracks;
  typedef boost::sub_range<std::vector<SiStripClusterWithTracks> > SiStripClustersWithTracks;


  // sim strip split
  typedef std::pair<uint32_t, EncodedEventId> SimHitIdpr;
  TrackerHitAssociator::Config trackerHitAssociatorConfig_;
  std::unique_ptr<TrackerHitAssociator> hitAssociator;
  
  template<typename C> 
  static const C* getCluster(const TrackingRecHit* hit) ;
  
  template<typename C> 
  static const C* equalClusters(const C &c1, const C &c2) 
  { 
    return nullptr; 
  }
  
  // Find a rechit in a vector of ClusterWithTrack
  template<typename Cluster> class FindCluster 
  {
    
  public:

    FindCluster(const TrackingRecHit* hit) : toFind_( getCluster<Cluster>(hit) ) { } 
    
    bool operator()(const ClusterWithTracks<Cluster> &test) const 
    { 
      assert(test.cluster); // make sure this is not 0
      return test.cluster == toFind_ || equalClusters<Cluster>(*test.cluster, *toFind_); 
    }

  private:

    const Cluster* toFind_;

  };
  
  // Attach tracks to cluster ?!?!
  template<typename Cluster>
  void markClusters(std::map<uint32_t, boost::sub_range<std::vector<ClusterWithTracks<Cluster> > > >& map, 
            const TrackingRecHit* hit, 
            const reco::Track* track, 
            const TrajectoryStateOnSurface& tsos) const ;
  
  template<typename Cluster>
  std::unique_ptr<edmNew::DetSetVector<Cluster> > 
  splitClusters(const std::map<uint32_t, 
        boost::sub_range<std::vector<ClusterWithTracks<Cluster> > > > &input, 
        const reco::Vertex &vtx) const ;
  
  template<typename Cluster>
  void splitCluster(const ClusterWithTracks<Cluster> &cluster, 
            const GlobalVector &dir, 
            typename edmNew::DetSetVector<Cluster>::FastFiller &output,
            DetId detId) const ;
  
  std::vector<SiPixelClusterWithTracks> allSiPixelClusters;
  std::map<uint32_t, SiPixelClustersWithTracks> siPixelDetsWithClusters; 

  std::vector<SiStripClusterWithTracks> allSiStripClusters;
  std::map<uint32_t, SiStripClustersWithTracks> siStripDetsWithClusters;


};

template<> const SiPixelCluster * TrackClusterSplitter::getCluster<SiPixelCluster>(const TrackingRecHit *hit) ;

template<>
void TrackClusterSplitter::splitCluster<SiPixelCluster> (const SiPixelClusterWithTracks &cluster, 
                             const GlobalVector &dir, 
                             edmNew::DetSetVector<SiPixelCluster>::FastFiller &output,
                             DetId detId
                             ) const ;

template<> const SiStripCluster * TrackClusterSplitter::getCluster<SiStripCluster>(const TrackingRecHit *hit) ;

template<>
void TrackClusterSplitter::splitCluster<SiStripCluster> (const SiStripClusterWithTracks &cluster, 
                             const GlobalVector &dir, 
                             edmNew::DetSetVector<SiStripCluster>::FastFiller &output,
                             DetId detId
                             ) const ;


#define foreach BOOST_FOREACH

TrackClusterSplitter::TrackClusterSplitter(const edm::ParameterSet& iConfig):
  useTrajectories_(iConfig.getParameter<bool>("useTrajectories")),
  trackerHitAssociatorConfig_(consumesCollector())
{
  if (useTrajectories_) {
    trajTrackAssociations_ = consumes<TrajTrackAssociationCollection>(iConfig.getParameter<edm::InputTag>("trajTrackAssociations"));
  } else {
    propagatorName_ = iConfig.getParameter<std::string>("propagator");
    tracks_ = consumes<std::vector<reco::Track> >(iConfig.getParameter<edm::InputTag>("tracks"));
  }

  pixelClusters_ = consumes<edmNew::DetSetVector<SiPixelCluster> >(iConfig.getParameter<edm::InputTag>("pixelClusters"));
  stripClusters_ = consumes<edmNew::DetSetVector<SiStripCluster> >(iConfig.getParameter<edm::InputTag>("stripClusters"));
  vertices_ = consumes<std::vector<reco::Vertex> >(iConfig.getParameter<edm::InputTag>("vertices"));

  produces< edmNew::DetSetVector<SiPixelCluster> >();

  produces< edmNew::DetSetVector<SiStripCluster> >();
  
  simSplitPixel_ = (iConfig.getParameter<bool>("simSplitPixel"));
  simSplitStrip_ = (iConfig.getParameter<bool>("simSplitStrip"));
  tmpSplitPixel_ = (iConfig.getParameter<bool>("tmpSplitPixel")); // not so nice... you don't want two bool but some switch
  tmpSplitStrip_ = (iConfig.getParameter<bool>("tmpSplitStrip"));

  useStraightTracks_ = (iConfig.getParameter<bool>("useStraightTracks"));


  if ( simSplitPixel_ ) pixeldigisimlinkToken = consumes< edm::DetSetVector<PixelDigiSimLink> >(edm::InputTag("simSiPixelDigis"));
  if ( simSplitStrip_ ) stripdigisimlinkToken = consumes< edm::DetSetVector<StripDigiSimLink> >(edm::InputTag("simSiStripDigis"));



  /*
    cout << "TrackClusterSplitter : " << endl;
    cout << endl << endl << endl;
    cout << "(int)simSplitPixel_   = " << (int)simSplitPixel_  << endl;
    cout << "(int)simSplitStrip_   = " << (int)simSplitStrip_  << endl;
    cout << "(int)tmpSplitPixel_   = " << (int)tmpSplitPixel_  << endl;
    cout << "(int)tmpSplitStrip_   = " << (int)tmpSplitStrip_  << endl;
    cout << "stripClusters_        = " << stripClusters_        << endl;
    cout << "pixelClusters_        = " << pixelClusters_        << endl;
    cout << "(int)useTrajectories_ = " << (int)useTrajectories_ << endl;
    cout << "trajectories_         = " << trajectories_         << endl;
    cout << "propagatorName_       = " << propagatorName_       << endl;
    cout << "vertices_             = " << vertices_             << endl;
    cout << "useStraightTracks_    = " << useStraightTracks_    << endl;
    cout << endl << endl << endl;
  */

  // Load template; 40 for barrel and 41 for endcaps
  SiPixelTemplate::pushfile( 40, thePixelTemp_ );
  SiPixelTemplate::pushfile( 41, thePixelTemp_ );
  SiPixelTemplate2D::pushfile( 40, thePixelTemp2D_ );
  SiPixelTemplate2D::pushfile( 41, thePixelTemp2D_ );

  // Load strip templates
  SiStripTemplate::pushfile( 11, theStripTemp_ );
  SiStripTemplate::pushfile( 12, theStripTemp_ );
  SiStripTemplate::pushfile( 13, theStripTemp_ );
  SiStripTemplate::pushfile( 14, theStripTemp_ );
  SiStripTemplate::pushfile( 15, theStripTemp_ );
  SiStripTemplate::pushfile( 16, theStripTemp_ );

}


template<>
const SiStripCluster*
TrackClusterSplitter::getCluster<SiStripCluster>(const TrackingRecHit* hit) 
{
  if ( typeid(*hit) == typeid(SiStripRecHit2D) ) 
    {
      return (static_cast<const SiStripRecHit2D &>(*hit)).cluster().get();
    } 
  else if ( typeid(*hit) == typeid(SiStripRecHit1D) ) 
    {
      return (static_cast<const SiStripRecHit1D &>(*hit)).cluster().get();
    } 
  else 
    throw cms::Exception("Unsupported") << "Detid of type " << typeid(*hit).name() << " not supported.\n";
}

template<>
const SiPixelCluster*
TrackClusterSplitter::getCluster<SiPixelCluster>(const TrackingRecHit* hit) 
{
  if ( typeid(*hit) == typeid(SiPixelRecHit) ) 
    {
      return (static_cast<const SiPixelRecHit&>(*hit)).cluster().get();
    } 
  else 
    throw cms::Exception("Unsupported") << "Detid of type " << typeid(*hit).name() << " not supported.\n";
}

TrackClusterSplitter::~TrackClusterSplitter()
{
}

void
TrackClusterSplitter::produce(edm::Event& iEvent, const edm::EventSetup& iSetup)
{
  using namespace edm;

  iSetup.get<GlobalTrackingGeometryRecord>().get(geometry_);  
  
  if ( !useTrajectories_ ) 
    {
      iSetup.get<IdealMagneticFieldRecord>().get( magfield_ );
      iSetup.get<TrackingComponentsRecord>().get( "AnalyticalPropagator", propagator_ );
    }
 
  Handle<edmNew::DetSetVector<SiPixelCluster> > inputPixelClusters;
  Handle<edmNew::DetSetVector<SiStripCluster> > inputStripClusters;
  
  iEvent.getByToken(pixelClusters_, inputPixelClusters);
  
  iEvent.getByToken(stripClusters_, inputStripClusters);
  
  if(simSplitStrip_)
    hitAssociator.reset(new TrackerHitAssociator(iEvent, trackerHitAssociatorConfig_));

    
  allSiPixelClusters.clear(); siPixelDetsWithClusters.clear();
  allSiStripClusters.clear(); siStripDetsWithClusters.clear();

  
  allSiPixelClusters.reserve(inputPixelClusters->dataSize()); // this is important, otherwise push_back invalidates the iterators
  allSiStripClusters.reserve(inputStripClusters->dataSize()); // this is important, otherwise push_back invalidates the iterators

  
  // fill in the list of all tracks
  foreach(const edmNew::DetSet<SiPixelCluster> &ds, *inputPixelClusters) 
    {
      std::vector<SiPixelClusterWithTracks>::iterator start = allSiPixelClusters.end();
      allSiPixelClusters.insert(start, ds.begin(), ds.end());
    
      std::vector<SiPixelClusterWithTracks>::iterator end   = allSiPixelClusters.end();
      siPixelDetsWithClusters[ds.detId()] = SiPixelClustersWithTracks(start,end);
    }
 
  foreach(const edmNew::DetSet<SiStripCluster> &ds, *inputStripClusters) 
    {
      std::vector<SiStripClusterWithTracks>::iterator start = allSiStripClusters.end();
      allSiStripClusters.insert(start, ds.begin(), ds.end());
     
      std::vector<SiStripClusterWithTracks>::iterator end   = allSiStripClusters.end();
      siStripDetsWithClusters[ds.detId()] = SiStripClustersWithTracks(start,end);
    }
  
  if ( useTrajectories_ ) 
    { 
      // Here use the fully reconstructed tracks to get the track angle

      Handle<TrajTrackAssociationCollection> trajectories; 
      iEvent.getByToken(trajTrackAssociations_, trajectories);
      for ( TrajTrackAssociationCollection::const_iterator it = trajectories->begin(), 
          ed = trajectories->end(); it != ed; ++it ) 
    { 
      const Trajectory  & traj =  *it->key;
      const reco::Track * tk   = &*it->val;
      
      if ( traj.measurements().size() != tk->recHitsSize() ) 
        throw cms::Exception("Aargh") << "Sizes don't match: traj " << traj.measurements().size()  
                      << ", tk " << tk->recHitsSize() << "\n";
      
      trackingRecHit_iterator it_hit = tk->recHitsBegin(), ed_hit = tk->recHitsEnd();
      
      const Trajectory::DataContainer & tms = traj.measurements();
      
      size_t i_hit = 0, last_hit = tms.size()-1;
      
      bool first = true, reversed = false;
      
      for (; it_hit != ed_hit; ++it_hit, ++i_hit) 
        {
          // ignore hits with no detid

          if ((*it_hit)->geographicalId().rawId() == 0)
        {
          //cout << "It should never happen that a trackingRecHit has no detector ID !!!!!!!!!!!!!!!!! " << endl;
          continue;
        }

          // if it's the first hit, check the ordering of track vs trajectory
          if (first) 
        {
          
          if ((*it_hit)->geographicalId() == tms[i_hit].recHit()->hit()->geographicalId()) 
            {
              reversed = false;
                    } 
          else if ((*it_hit)->geographicalId() == tms[last_hit-i_hit].recHit()->hit()->geographicalId()) 
            {
              reversed = true;
                    } 
          else 
            {
              throw cms::Exception("Aargh") << "DetIDs don't match either way :-( \n";
                    }
                }  

          const TrackingRecHit *hit = *it_hit;
          if ( hit == nullptr || !hit->isValid() )
        continue;
          
          int subdet = hit->geographicalId().subdetId();
          
          if (subdet >= 3) 
        { // strip
          markClusters<SiStripCluster>(siStripDetsWithClusters, hit, tk, tms[reversed ? last_hit-i_hit : i_hit].updatedState());
                } 
          else if (subdet >= 1) 
        { // pixel
          markClusters<SiPixelCluster>(siPixelDetsWithClusters, hit, tk, tms[reversed ? last_hit-i_hit : i_hit].updatedState());
                } 
          else 
        {
          edm::LogWarning("HitNotFound") << "Hit of type " << typeid(*hit).name() << ",  detid " 
                         << hit->geographicalId().rawId() << ", subdet " << subdet;
                }
            }
        }
    } 
  else 
    {
      // Here use the pixel tracks to get the track angles

      Handle<std::vector<reco::Track> > tracks; 
      iEvent.getByToken(tracks_, tracks);
      //TrajectoryStateTransform transform;
      foreach (const reco::Track &track, *tracks) 
    {
      FreeTrajectoryState atVtx   =  trajectoryStateTransform::innerFreeState(track, &*magfield_);
      trackingRecHit_iterator it_hit = track.recHitsBegin(), ed_hit = track.recHitsEnd();
      for (; it_hit != ed_hit; ++it_hit) 
        {
          const TrackingRecHit *hit = *it_hit;
          if ( hit == nullptr || !hit->isValid() ) 
        continue;
          
          int subdet = hit->geographicalId().subdetId();

          if ( subdet == 0 ) 
        continue;
          
          const GeomDet *det = geometry_->idToDet( hit->geographicalId() );
          
          if ( det == nullptr ) 
        {
          edm::LogError("MissingDetId") << "DetIDs " << (int)(hit->geographicalId()) << " is not in geometry.\n";
          continue;
                }
          
          TrajectoryStateOnSurface prop = propagator_->propagate(atVtx, det->surface());
          if ( subdet >= 3 ) 
        { // strip
          markClusters<SiStripCluster>(siStripDetsWithClusters, hit, &track, prop);
                } 
          else if (subdet >= 1) 
        { // pixel
          markClusters<SiPixelCluster>(siPixelDetsWithClusters, hit, &track, prop);
                } 
          else 
        {
          edm::LogWarning("HitNotFound") << "Hit of type " << typeid(*hit).name() << ",  detid " 
                         << hit->geographicalId().rawId() << ", subdet " << subdet;
        }
            }
        }
    }

  Handle<std::vector<reco::Vertex> > vertices; 
  iEvent.getByToken(vertices_, vertices);
  
  // Needed in case of simsplit
  if ( simSplitPixel_ )
    iEvent.getByToken(pixeldigisimlinkToken, pixeldigisimlink);
    
  // Needed in case of strip simsplit
  if ( simSplitStrip_ )
    iEvent.getByToken(stripdigisimlinkToken, stripdigisimlink);

  // gavril : to do: choose the best vertex here instead of just choosing the first one ? 
  std::unique_ptr<edmNew::DetSetVector<SiPixelCluster> > newPixelClusters( splitClusters( siPixelDetsWithClusters, vertices->front() ) );
  std::unique_ptr<edmNew::DetSetVector<SiStripCluster> > newStripClusters( splitClusters( siStripDetsWithClusters, vertices->front() ) );
  
  iEvent.put(std::move(newPixelClusters));
  iEvent.put(std::move(newStripClusters));
    
  allSiPixelClusters.clear(); siPixelDetsWithClusters.clear();
  allSiStripClusters.clear(); siStripDetsWithClusters.clear();

}

template<typename Cluster>
void TrackClusterSplitter::markClusters( std::map<uint32_t, boost::sub_range<std::vector<ClusterWithTracks<Cluster> > > >& map, 
                     const TrackingRecHit* hit, 
                     const reco::Track* track, 
                     const TrajectoryStateOnSurface& tsos) const 
{
  boost::sub_range<std::vector<ClusterWithTracks<Cluster> > >& range = map[hit->geographicalId().rawId()];
  
  typedef typename std::vector<ClusterWithTracks<Cluster> >::iterator IT;
  IT match = std::find_if(range.begin(), range.end(), FindCluster<Cluster>(hit));
  
  if ( match != range.end() ) 
    {
      match->tracks.push_back( TrackAndState(track,tsos) );
    } 
  else 
    {
      edm::LogWarning("ClusterNotFound") << "Cluster of type " << typeid(Cluster).name() << " on detid " 
                     << hit->geographicalId().rawId() << " from hit of type " << typeid(*hit).name();
    }
}

template<typename Cluster>
std::unique_ptr<edmNew::DetSetVector<Cluster> > 
TrackClusterSplitter::splitClusters(const std::map<uint32_t, boost::sub_range<std::vector<ClusterWithTracks<Cluster> > > > &input, 
                    const reco::Vertex &vtx) const 
{
  auto output = std::make_unique<edmNew::DetSetVector<Cluster>>();
  typedef std::pair<uint32_t, boost::sub_range<std::vector<ClusterWithTracks<Cluster> > > > pair;
  
  foreach(const pair &p, input) 
    {
      const GeomDet* det = geometry_->idToDet( DetId(p.first) );
      
      if ( det == nullptr ) 
        { 
          edm::LogError("MissingDetId") << "DetIDs " << p.first << " is not in geometry.\n";
      continue;
    }
      
      // gavril: Pass the PV instead of direction
      // GlobalVector dir(det->position().x() - vtx.x(), det->position().y() - vtx.y(), det->position().z() - vtx.z());
      GlobalVector primary_vtx( vtx.x(), vtx.y(), vtx.z() );

      // Create output collection
      typename edmNew::DetSetVector<Cluster>::FastFiller detset(*output, p.first);
      
      // fill it
      foreach(const ClusterWithTracks<Cluster> &c, p.second) 
    {
      splitCluster(c, primary_vtx, detset, DetId(p.first) );
        }
    }

  return output;
}

template<typename Cluster>
void TrackClusterSplitter::splitCluster(const ClusterWithTracks<Cluster> &cluster, 
                    const GlobalVector &dir, 
                    typename edmNew::DetSetVector<Cluster>::FastFiller &output, 
                    DetId detId) const 
{
  //cout << "Should never be here: TrackClusterSplitter, TrackClusterSplitter::splitCluster(...)  !!!!!!!!!!!!!!!!!!!!!!!!!!!!! " << endl;
  throw cms::Exception("LogicError", "This should not be called");
}

template<>
void TrackClusterSplitter::splitCluster<SiStripCluster> (const SiStripClusterWithTracks& c, 
                             const GlobalVector &vtx, 
                             edmNew::DetSetVector<SiStripCluster>::FastFiller &output,
                             DetId detId
                             ) const 
{ 
  if ( simSplitStrip_ )
    {      
      bool cluster_was_successfully_split = false;
            
      const SiStripCluster* clust = static_cast<const SiStripCluster*>(c.cluster);
      
      std::vector<SimHitIdpr> associatedIdpr;
      
      hitAssociator->associateSimpleRecHitCluster(clust, detId, associatedIdpr);

      size_t splittableClusterSize = 0;
      splittableClusterSize = associatedIdpr.size();
      auto const & amp = clust->amplitudes();
      int clusiz = amp.size();
      associatedIdpr.clear();

      SiStripDetId ssdid( detId );

      // gavril : sim splitting can be applied to the forward detectors as well...

      if ( ( splittableClusterSize > 1 && amp.size() > 2 ) && 
       ( (int)ssdid.moduleGeometry() == 1 || 
         (int)ssdid.moduleGeometry() == 2 || 
         (int)ssdid.moduleGeometry() == 3 || 
         (int)ssdid.moduleGeometry() == 4 ) )
    {
      
      edm::DetSetVector<StripDigiSimLink>::const_iterator isearch = stripdigisimlink->find(detId);
      
      int first  = clust->firstStrip();
      int last   = first + clusiz;
      uint16_t rawAmpl = 0, currentAmpl = 0;
      
      std::vector<uint16_t> tmp1, tmp2;
      
      std::vector<int> firstStrip;
      std::vector<bool> trackInStrip;
      std::vector<unsigned int> trackID;
      std::vector<float> trackFraction;
      std::vector< std::vector<uint16_t> > trackAmp;
      unsigned int currentChannel( 9999 );
      unsigned int thisTrackID = 0;

      if ( isearch != stripdigisimlink->end() ) 
        {
          edm::DetSet<StripDigiSimLink> link_detset = (*isearch);
          
          for ( edm::DetSet<StripDigiSimLink>::const_iterator linkiter = link_detset.data.begin();
          linkiter != link_detset.data.end(); linkiter++)
        {
          if ( (int)(linkiter->channel()) >= first  && (int)(linkiter->channel()) < last  )
            {
              int stripIdx = (int)linkiter->channel()-first;
              rawAmpl = (uint16_t)(amp[stripIdx]);  
              
              // DigiSimLinks are ordered first by channel; there can be > 1 track, and > 1 simHit for each track
              
              if ( linkiter->channel() != currentChannel ) 
            {
              // New strip; store amplitudes for the previous one
              uint16_t thisAmpl;
              
              for (size_t i=0; i<trackID.size(); ++i)  
                {
                  if ( trackInStrip[i] ) 
                {
                  if ( ( thisAmpl=currentAmpl ) < 254 )
                    thisAmpl = min( uint16_t(253), max(uint16_t(0), (uint16_t)(currentAmpl*trackFraction[i]+0.5)) );
                  trackAmp[i].push_back( thisAmpl );
                }
                  
                  trackFraction[i] = 0;
                  trackInStrip[i] = false;
                }
              
              currentChannel = linkiter->channel();
            }
              
              // Now deal with this new DigiSimLink
              thisTrackID = linkiter->SimTrackId();
              
              // Have we seen this track yet?
              bool newTrack = true;
              int thisTrackIdx = 9999;
              
              for (size_t i=0; i<trackID.size(); ++i) 
            {
              if ( trackID[i] == thisTrackID ) 
                {
                  thisTrackIdx = i;
                  newTrack = false;
                }
            }
             
              if ( newTrack ) 
            {
              trackInStrip.push_back(false);  // We'll set it true below
              trackID.push_back(thisTrackID);
              firstStrip.push_back(currentChannel);
              std::vector<uint16_t> ampTmp;
              trackAmp.push_back(ampTmp);
              trackFraction.push_back(0);
              thisTrackIdx = trackID.size()-1;
            }
              
              trackInStrip[thisTrackIdx] = true;
              trackFraction[thisTrackIdx] += linkiter->fraction();
              currentAmpl = rawAmpl;
               
            }
          
        }// end of loop over DigiSimLinks
          
          // we want to continue here!!!!
          
          std::vector<SiStripCluster> newCluster;
          // Fill amplitudes for the last strip and create a cluster for each track
          uint16_t thisAmpl;
          
          for (size_t i=0; i < trackID.size(); ++i) 
        { 
          if ( trackInStrip[i] ) 
            {
              if ( ( thisAmpl=rawAmpl ) < 254 ) 
            thisAmpl = min(uint16_t(253), max(uint16_t(0), (uint16_t)(rawAmpl*trackFraction[i]+0.5)));
              
              if ( thisAmpl > 0 )
            trackAmp[i].push_back( thisAmpl );
              //else
              //cout << "thisAmpl = " << (int)thisAmpl << endl;
            }
          
          newCluster.push_back( SiStripCluster( 
                            firstStrip[i],
                            trackAmp[i].begin(), 
                            trackAmp[i].end() ) );
          
        }
          
          
          for ( size_t i=0; i<newCluster.size(); ++i )
        {
          
          // gavril : This is never used. Will use it below 
          float clusterAmp = 0.0;
          for (size_t j=0; j<trackAmp[i].size(); ++j ) 
            clusterAmp += (float)(trackAmp[i])[j];
          
          if ( clusterAmp > 0.0 && firstStrip[i] != 9999 && !trackAmp[i].empty()  ) 
            { 
              // gavril :  I think this should work
              output.push_back( newCluster[i] );
              
              //cout << endl << endl << endl; 
              //cout << "(int)(newCluster[i].amplitudes().size()) = " << (int)(newCluster[i].amplitudes().size()) << endl;
              //for ( int j=0; j<(int)(newCluster[i].amplitudes().size()); ++j )
              //cout << "(newCluster[i].amplitudes())[j] = " << (int)(newCluster[i].amplitudes())[j] << endl;
              
              cluster_was_successfully_split = true;
            } 
          else 
            {
              //std::cout << "\t\t Rejecting new cluster" << std::endl;
              
              // gavril : I think this pointer should be deleted above
              //delete newCluster[i];
            }
        }
                
        } // if ( isearch != stripdigisimlink->end() ) ... 
      else 
        {
          // Do nothing...
        }
    }
      
      
      if ( !cluster_was_successfully_split )
    output.push_back( *c.cluster ); 
      
    } // end of   if ( strip_simSplit_ )...
  
  else if ( tmpSplitStrip_ )
   {
      bool cluster_was_successfully_split = false;
      
      const SiStripCluster* theStripCluster = static_cast<const SiStripCluster*>(c.cluster);
      
      if ( theStripCluster )
    {
      //SiStripDetId ssdid( theStripCluster->geographicalId() );
      SiStripDetId ssdid( detId.rawId() );

      // Do not attempt to split clusters of size less than or equal to one.
      // Only split clusters in IB1, IB2, OB1, OB2 (TIB and TOB).

      if ( (int)theStripCluster->amplitudes().size() <= 1 || 
           ( (int)ssdid.moduleGeometry() != 1 && 
         (int)ssdid.moduleGeometry() != 2 && 
         (int)ssdid.moduleGeometry() != 3 && 
         (int)ssdid.moduleGeometry() != 4 ) )
        {    
          // Do nothing.
          //cout << endl;
          //cout << "Will NOT attempt to split this clusters: " << endl;
          //cout << "(int)theStripCluster->amplitudes().size() = " << (int)theStripCluster->amplitudes().size() << endl;
          //cout << "(int)ssdid.moduleGeometry() = " << (int)ssdid.moduleGeometry() << endl;
          
        }
      else // if ( (int)theStripCluster->amplitudes().size() <= 1 )
        {
         
          //cout << endl;
          //cout << "Will attempt to split this clusters: " << endl;

          int ID = -99999;
                 
          int is_stereo = (int)( ssdid.stereo() ); 
          
          if      ( ssdid.moduleGeometry() == 1 ) // IB1 
        {
          if ( !is_stereo ) 
            ID = 11;
          else
            ID = 12;
        }
          else if ( ssdid.moduleGeometry() == 2 ) // IB2
        {
          ID = 13;
        }
          else if ( ssdid.moduleGeometry() == 3 ) // OB1
        {
          ID = 16; 
        }
          else if ( ssdid.moduleGeometry() == 4 ) // OB2
        {
          if ( !is_stereo )
            ID = 14;
          else
            ID = 15;
        }
          else 
        {
          throw cms::Exception("TrackClusterSplitter::splitCluster") 
            << "\nERROR: Wrong strip teplate ID. Should only use templates for IB1, IB2, OB1 and OB2 !!!" << "\n\n";
        }
          



          // Begin: determine incident angles ============================================================
          
          float cotalpha_ = -99999.9;
          float cotbeta_  = -99999.9;
          
          // First, determine track angles from straight track approximation
          
          // Find crude cluster center
          // gavril : This is in local coordinates ? 
          float xcenter = theStripCluster->barycenter();
         
          const GeomDetUnit* theDet = geometry_->idToDetUnit( detId );
          const StripGeomDetUnit* stripDet = dynamic_cast<const StripGeomDetUnit*>( theDet );
              
          if ( !stripDet )
        {
          throw cms::Exception("TrackClusterSplitter : ") 
            << "\nERROR: Wrong stripDet !!! " << "\n\n";
        }


          const StripTopology* theTopol = &( stripDet->specificTopology() );

          // Transform from measurement to local coordinates (in cm)
          // gavril: may have to differently if kicks/bows are introduced. However, at this point there are no tracks...:
          // LocalPoint lp = theTopol->localPosition( xcenter, /*const Topology::LocalTrackPred & */ trkPred );

          // gavril : What is lp.y() for strips ? It is zero, but is that the strip center or one of the ends ? 
          LocalPoint lp = theTopol->localPosition( xcenter );
          
          // Transform from local to global coordinates
          GlobalPoint gp0 = theDet->surface().toGlobal( lp );
          
           // Make a vector pointing from the PV to the cluster center 
          GlobalPoint gp(gp0.x()-vtx.x(), gp0.y()-vtx.y(), gp0.z()-vtx.z() );
          
          // Make gp a unit vector, gv, pointing from the PV to the cluster center
          float gp_mod = sqrt( gp.x()*gp.x() + gp.y()*gp.y() + gp.z()*gp.z() );
          float gpx = gp.x()/gp_mod;
          float gpy = gp.y()/gp_mod;
          float gpz = gp.z()/gp_mod;
          GlobalVector gv(gpx, gpy, gpz);

          // Make unit vectors in local coordinates and then transform them in global coordinates
          const Local3DVector lvx(1.0, 0.0, 0.0);
          GlobalVector gvx = theDet->surface().toGlobal( lvx );
          const Local3DVector lvy(0.0, 1.0, 0.0);
          GlobalVector gvy = theDet->surface().toGlobal( lvy );
          const Local3DVector lvz(0.0, 0.0, 1.0);
          GlobalVector gvz = theDet->surface().toGlobal( lvz );
          
          // Calculate angles alpha and beta
          float gv_dot_gvx = gv.x()*gvx.x() + gv.y()*gvx.y() + gv.z()*gvx.z();
          float gv_dot_gvy = gv.x()*gvy.x() + gv.y()*gvy.y() + gv.z()*gvy.z();
          float gv_dot_gvz = gv.x()*gvz.x() + gv.y()*gvz.y() + gv.z()*gvz.z();
          
          // gavril : check beta !!!!!!!!!!!!
          //float alpha_ = atan2( gv_dot_gvz, gv_dot_gvx );
          //float beta_  = atan2( gv_dot_gvz, gv_dot_gvy );
          
          cotalpha_ = gv_dot_gvx / gv_dot_gvz;
          cotbeta_  = gv_dot_gvy / gv_dot_gvz;
           
          // Attempt to get a better angle from tracks (either pixel tracks or full tracks)
          if ( !useStraightTracks_ )
        {
          //cout << "TrackClusterSplitter.cc : " << endl;
          //cout << "Should not be here for now !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! " << endl;

          // Use either pixel tracks (useTrajectories_ = False) or fully reconstructed tracks (useTrajectories_ = True)
          // When pixel/full tracks are not associated with the current cluster, will use angles from straight tracks
          
          // These are the tracks associated with this cluster
          std::vector<TrackAndState> vec_tracks_states = c.tracks;

          if ( (int)vec_tracks_states.size() > 0 )
            {
              //cout << "There is at least one track associated with this cluster. Pick the one with largest Pt." << endl;
              //cout << "(int)vec_tracks_states.size() = " << (int)vec_tracks_states.size() << endl;
              
              int index_max_pt = -99999;  // index of the track with the highest Pt
              float max_pt = -99999.9;
              
              for (int i=0; i<(int)vec_tracks_states.size(); ++i )
            {
              const reco::Track* one_track = vec_tracks_states[i].track;
              
              if ( one_track->pt() > max_pt )
                {
                  index_max_pt = i;
                  max_pt = one_track->pt();
                }  
            }
              
              // Pick the tsos from the track with highest Pt
              // gavril: Should we use highest Pt or best Chi2 ?
              TrajectoryStateOnSurface one_tsos = vec_tracks_states[index_max_pt].state;
              
              LocalTrajectoryParameters ltp = one_tsos.localParameters();
              
              LocalVector localDir = ltp.momentum()/ltp.momentum().mag();
              
              float locx = localDir.x();
              float locy = localDir.y();
              float locz = localDir.z();
              
              //alpha_ = atan2( locz, locx );
              //beta_  = atan2( locz, locy );
              
              cotalpha_ = locx/locz;
              cotbeta_  = locy/locz;
              
            } // if ( (int)vec_tracks_states.size() > 0 )
              
        } // if ( !useStraightTracks_ )


          // End: determine incident angles ============================================================


          // Calculate strip cluster charge and store amplitudes in vector for later use
          
          //cout << endl;
          //cout << "Calculate strip cluster charge and store amplitudes in vector for later use" << endl;

          float strip_cluster_charge = 0.0;
          std::vector<float> vec_cluster_charge; 
          vec_cluster_charge.clear();
          int cluster_size = (int)( (theStripCluster->amplitudes()).size() );
          
          int cluster_charge = 0;
          for (int i=0; i<cluster_size; ++i)
        {
          float current_strip_charge = (float)( (theStripCluster->amplitudes())[i] );

          strip_cluster_charge += current_strip_charge;
          vec_cluster_charge.push_back( current_strip_charge );  
        
          cluster_charge +=current_strip_charge; 
        }
         
       
          //cout << endl;
          //cout << "Calling strip qbin to see if the strip cluster has to be split..." << endl;          
              SiStripTemplate strip_templ_(theStripTemp_);
          int strip_templQbin_ = strip_templ_.qbin( ID, cotalpha_, cotbeta_, strip_cluster_charge );

          if ( strip_templQbin_ < 0 || strip_templQbin_ > 5 )
        {
          // Do nothing...
          // cout << "Wrong strip strip_templQbin_ = " << strip_templQbin_ << endl;
        } // if ( strip_templQbin_ < 0 || strip_templQbin_ > 5 )
          else // if ( strip_templQbin_ < 0 || strip_templQbin_ > 5 ) {...} else
        {
          if ( strip_templQbin_ != 0 ) 
            {
              // Do not split this cluster. Do nothing.
              //cout << endl;
              //cout << "Do NOT split this cluster" << endl;

            } // if ( strip_templQbin_ != 0 ) 
          else // if ( templQbin_ != 0 ) {...} else
            {
              //cout << endl;
              //cout << "Split this cluster" << endl;

              // gavril : Is this OK ?
              uint16_t first_strip = theStripCluster->firstStrip();
 
              LocalVector lbfield = ( stripDet->surface() ).toLocal( magfield_->inTesla( stripDet->surface().position() ) ); 
              float locBy = lbfield.y();
              
              // Initialize values coming back from SiStripTemplateSplit::StripTempSplit
              float stripTemplXrec1_  = -99999.9;
              float stripTemplXrec2_  = -99999.9;
              float stripTemplSigmaX_ = -99999.9;
              float stripTemplProbX_  = -99999.9;
              int   stripTemplQbin_   = -99999;
              float stripTemplProbQ_  = -99999.9;


              /*
            cout << endl;
            cout << "About to call SiStripTemplateSplit::StripTempSplit(...)" << endl;
            
            cout << endl;
            cout << "ID        = " << ID        << endl;
            cout << "cotalpha_ = " << cotalpha_ << endl;
            cout << "cotbeta_  = " << cotbeta_  << endl;
            cout << "locBy     = " << locBy     << endl;
            cout << "Amplitudes: "; 
            for (int i=0; i<(int)vec_cluster_charge.size(); ++i)
            cout << vec_cluster_charge[i] << ", ";
            cout << endl;
              */

              int ierr =
            SiStripTemplateSplit::StripTempSplit(ID, 
                                 cotalpha_, cotbeta_, 
                                 locBy, 
                                 vec_cluster_charge, 
                                 strip_templ_, 
                                 stripTemplXrec1_, 
                                 stripTemplXrec2_, 
                                 stripTemplSigmaX_, 
                                 stripTemplProbX_,
                                 stripTemplQbin_,
                                 stripTemplProbQ_ );
              
             

              stripTemplXrec1_ += 2*strip_templ_.xsize();
              stripTemplXrec2_ += 2*strip_templ_.xsize();
              
            

              if ( ierr != 0 )
            {
              //cout << endl;
              //cout << "Strip cluster splitting failed: ierr = " << ierr << endl;
            }
              else // if ( ierr != 0 )
            {
              // Cluster was successfully split. 
              // Make the two split clusters and put them in the split cluster collection
              
              //cout << endl; 
              //cout << "Cluster was successfully split" << endl;

              cluster_was_successfully_split = true;

              std::vector<float> strip_cluster1;
              std::vector<float> strip_cluster2;

              strip_cluster1.clear();
              strip_cluster2.clear();
              
              // gavril : Is this OK ?!?!?!?! 
              for (int i=0; i<BXSIZE; ++i)
                {
                  strip_cluster1.push_back(0.0);
                  strip_cluster2.push_back(0.0);
                }

              //cout << endl;
              //cout << "About to call interpolate and sxtemp" << endl;

              strip_templ_.interpolate(ID, cotalpha_, cotbeta_, locBy);
              strip_templ_.sxtemp(stripTemplXrec1_, strip_cluster1);
              strip_templ_.sxtemp(stripTemplXrec2_, strip_cluster2);
             
             
              
              vector<SiStripDigi> vecSiStripDigi1;
              vecSiStripDigi1.clear();  
              int strip_cluster1_size = (int)strip_cluster1.size();
              for (int i=2; i<strip_cluster1_size; ++i)
                {
                  if ( strip_cluster1[i] > 0.0 )
                {
                  SiStripDigi current_digi1( first_strip + i-2, strip_cluster1[i] ); 
                  
                  vecSiStripDigi1.push_back( current_digi1 );
                }
                }
               
              
              
              vector<SiStripDigi> vecSiStripDigi2;
              vecSiStripDigi2.clear();  
              int strip_cluster2_size = (int)strip_cluster2.size();
              for (int i=2; i<strip_cluster2_size; ++i)
                {
                  if ( strip_cluster2[i] > 0.0 )
                {
                  SiStripDigi current_digi2( first_strip + i-2, strip_cluster2[i] ); 
                  
                  vecSiStripDigi2.push_back( current_digi2 );
                }
                }
              
              
            
              
              std::vector<SiStripDigi>::const_iterator SiStripDigiIterBegin1 = vecSiStripDigi1.begin();
              std::vector<SiStripDigi>::const_iterator SiStripDigiIterEnd1   = vecSiStripDigi1.end();
              std::pair<std::vector<SiStripDigi>::const_iterator, 
                std::vector<SiStripDigi>::const_iterator> SiStripDigiRange1 
                = make_pair(SiStripDigiIterBegin1, SiStripDigiIterEnd1);

              //if ( SiStripDigiIterBegin1 == SiStripDigiIterEnd1 )
              //{
              //  throw cms::Exception("TrackClusterSplitter : ") 
              //<< "\nERROR: SiStripDigiIterBegin1 = SiStripDigiIterEnd1 !!!" << "\n\n";
              //}
              
              std::vector<SiStripDigi>::const_iterator SiStripDigiIterBegin2 = vecSiStripDigi2.begin();
              std::vector<SiStripDigi>::const_iterator SiStripDigiIterEnd2   = vecSiStripDigi2.end();
              std::pair<std::vector<SiStripDigi>::const_iterator, 
                std::vector<SiStripDigi>::const_iterator> SiStripDigiRange2 
                = make_pair(SiStripDigiIterBegin2, SiStripDigiIterEnd2);

              // Sanity check...
              //if ( SiStripDigiIterBegin2 == SiStripDigiIterEnd2 )
              //{
              //  cout << endl;
              //  cout << "SiStripDigiIterBegin2 = SiStripDigiIterEnd2 !!!!!!!!!!!!!!!" << endl;
              //}
              
              
              // Save the split clusters

              if ( SiStripDigiIterBegin1 != SiStripDigiIterEnd1 )
                {    
                  // gavril : Raw id ?
                  SiStripCluster cl1( SiStripDigiRange1 );

                  cl1.setSplitClusterError( stripTemplSigmaX_ );

                  output.push_back( cl1 );
                
                  if ( (int)cl1.amplitudes().size() <= 0 )
                {
                  throw cms::Exception("TrackClusterSplitter : ") 
                    << "\nERROR: (1) Wrong split cluster of size = " << (int)cl1.amplitudes().size() << "\n\n";
                }
                  
                } // if ( SiStripDigiIterBegin1 != SiStripDigiIterEnd1 )

              if ( SiStripDigiIterBegin2 != SiStripDigiIterEnd2 )
                {
                  // gavril : Raw id ?
                  SiStripCluster cl2( SiStripDigiRange2 );
                  cl2.setSplitClusterError( stripTemplSigmaX_ );
                  output.push_back( cl2 ); 
        
                  if ( (int)cl2.amplitudes().size() <= 0 )
                {
                  throw cms::Exception("TrackClusterSplitter : ") 
                    << "\nERROR: (2) Wrong split cluster of size = " << (int)cl2.amplitudes().size() << "\n\n";
                }
                  
                } // if ( SiStripDigiIterBegin2 != SiStripDigiIterEnd2 )
 
            
               
            } // else // if ( ierr != 0 )

            } // else // if ( strip_templQbin_ != 0 ) {...} else 
          
        } // else // if ( strip_templQbin_ < 0 || strip_templQbin_ > 5 ) {...} else

        } // else // if ( (int)theStripCluster->amplitudes().size() <= 1 )

      
      if ( !cluster_was_successfully_split )
        output.push_back( *c.cluster );

    } // if ( theStripCluster )
      else
    {
      throw cms::Exception("TrackClusterSplitter : ") 
        << "\nERROR: This is not a SiStripCluster  !!!" << "\n\n";
    }

    } // else if ( strip_tmpSplit_ )
  else
    {
      // gavril : Neither sim nor template splitter. Just add the cluster as it was. 
      output.push_back( *c.cluster );
    }
}

template<>
void TrackClusterSplitter::splitCluster<SiPixelCluster> (const SiPixelClusterWithTracks &c, 
                             const GlobalVector &vtx, 
                             edmNew::DetSetVector<SiPixelCluster>::FastFiller &output, 
                             DetId detId 
                             ) const 
{ 
  // The sim splitter:
  if ( simSplitPixel_ ) 
    {
      // cout << "Cluster splitting using simhits " << endl;
 
      int minPixelRow = (*c.cluster).minPixelRow();
      int maxPixelRow = (*c.cluster).maxPixelRow();
      int minPixelCol = (*c.cluster).minPixelCol();
      int maxPixelCol = (*c.cluster).maxPixelCol();    
      int dsl = 0; // number of digisimlinks
      
      edm::DetSetVector<PixelDigiSimLink>::const_iterator isearch = pixeldigisimlink->find(output.id());
      if (isearch != pixeldigisimlink->end()){
    edm::DetSet<PixelDigiSimLink> digiLink = (*isearch);
    
    edm::DetSet<PixelDigiSimLink>::const_iterator linkiter = digiLink.data.begin();
    //create a vector for the track ids in the digisimlinks
    std::vector<int> simTrackIdV;  
    simTrackIdV.clear();
    //create a vector for the new splittedClusters 
    std::vector<SiPixelCluster> splittedCluster;
    splittedCluster.clear();
    
    for ( ; linkiter != digiLink.data.end(); linkiter++) 
      { // loop over all digisimlinks 
        dsl++;
        std::pair<int,int> pixel_coord = PixelDigi::channelToPixel(linkiter->channel());
        
        // is the digisimlink inside the cluster boundaries?
        if ( pixel_coord.first  <= maxPixelRow && 
         pixel_coord.first  >= minPixelRow &&
         pixel_coord.second <= maxPixelCol &&
         pixel_coord.second >= minPixelCol ) 
          {
        bool inStock(false); // did we see this simTrackId before?
        
        SiPixelCluster::PixelPos newPixelPos(pixel_coord.first, pixel_coord.second); // coordinates to the pixel
        
        //loop over the pixels from the cluster to get the charge in this pixel
        int newPixelCharge(0); //fraction times charge in the original cluster pixel
        
        const std::vector<SiPixelCluster::Pixel>& pixvector = (*c.cluster).pixels();
        
        for(std::vector<SiPixelCluster::Pixel>::const_iterator itPix = pixvector.begin(); itPix != pixvector.end(); itPix++)
          {
            if (((int) itPix->x) == ((int) pixel_coord.first)&&(((int) itPix->y) == ((int) pixel_coord.second)))
              {
            newPixelCharge = (int) (linkiter->fraction()*itPix->adc); 
              }
          }
        
        if ( newPixelCharge < 2500 ) 
          continue; 
        
        //add the pixel to an already existing cluster if the charge is above the threshold
        int clusVecPos = 0;
        std::vector<int>::const_iterator sTIter =  simTrackIdV.begin();
          
        for ( ; sTIter < simTrackIdV.end(); sTIter++) 
          {
            if (((*sTIter)== (int) linkiter->SimTrackId())) 
              {
              inStock=true; // now we saw this id before
              //      //          std::cout << " adding a pixel to the cluster " << (int) (clusVecPos) <<std::endl;
              //      //            std::cout << "newPixelCharge " << newPixelCharge << std::endl;
              splittedCluster.at(clusVecPos).add(newPixelPos,newPixelCharge); // add the pixel to the cluster
              }
            clusVecPos++;
          }
        
          //look if the splitted cluster was already made before, if not create one
        
        if ( !inStock ) 
          {
            //      std::cout << "creating a new cluster " << std::endl;
            simTrackIdV.push_back(linkiter->SimTrackId()); // add the track id to the vector
          splittedCluster.push_back(SiPixelCluster(newPixelPos,newPixelCharge)); // add the cluster to the vector
          }
          }
      }
    
    //    std::cout << "will add clusters : simTrackIdV.size() " << simTrackIdV.size() << std::endl;
      
    if ( ( ( (int)simTrackIdV.size() ) == 1 ) || ( *c.cluster).size()==1 ) 
      { 
        //      cout << "putting in this cluster" << endl;
        output.push_back(*c.cluster );
        //      std::cout << "cluster added " << output.size() << std::endl;
      }
    else 
    {     
      for (std::vector<SiPixelCluster>::const_iterator cIter = splittedCluster.begin(); cIter != splittedCluster.end(); cIter++ )
        {
          output.push_back( (*cIter) );   
        }
    }
    
    simTrackIdV.clear();  
    splittedCluster.clear();
      }//if (isearch != pixeldigisimlink->end())
    }
  else if ( tmpSplitPixel_ )
    { 
      bool cluster_was_successfully_split = false;
      
      const SiPixelCluster* thePixelCluster = static_cast<const SiPixelCluster*>(c.cluster);

      if ( thePixelCluster )
    { 
      // Do not attempt to split clusters of size one
      if ( (int)thePixelCluster->size() <= 1 )
        {    
          // Do nothing.
          //cout << "Will not attempt to split this clusters: " << endl;
          //cout << "(int)thePixelCluster->size() = " << (int)thePixelCluster->size() << endl;
        }
      else
        {
          // For barrel use template id 40 and for endcaps use template id 41
          int ID = -99999;
          if ( (int)detId.subdetId() == (int)PixelSubdetector::PixelBarrel  )
        {
          //          cout << "We are in the barrel : " << (int)PixelSubdetector::PixelBarrel << endl;
          ID = 40;
        }
          else if ( (int)detId.subdetId() == (int)PixelSubdetector::PixelEndcap )
        {
          //          cout << "We are in the endcap : " << (int)PixelSubdetector::PixelEndcap << endl;
          ID = 41;
        }
          else 
        {
          // cout << "Not a pixel detector !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! " << endl;
        }
          

          // Begin: determine incident angles ============================================================

          float cotalpha_ = -99999.9;
          float cotbeta_  = -99999.9;

          // First, determine track angles from straight track approximation
 
          // Find crude cluster center. 
          float xcenter = thePixelCluster->x();
          float ycenter = thePixelCluster->y();
          
          const GeomDetUnit* theDet = geometry_->idToDetUnit( detId );
          const PixelGeomDetUnit* pixDet = dynamic_cast<const PixelGeomDetUnit*>( theDet );
          
          const PixelTopology* theTopol = (&(pixDet->specificTopology()));
        
          // Transform from measurement to local coordinates (in cm)
          LocalPoint lp = theTopol->localPosition( MeasurementPoint(xcenter, ycenter) );
          
          // Transform from local to global coordinates
          GlobalPoint gp0 = theDet->surface().toGlobal( lp );
          
          // Make a vector pointing from the PV to the cluster center 
          GlobalPoint gp(gp0.x()-vtx.x(), gp0.y()-vtx.y(), gp0.z()-vtx.z() );
          
          // Make gp a unit vector, gv, pointing from the PV to the cluster center
          float gp_mod = sqrt( gp.x()*gp.x() + gp.y()*gp.y() + gp.z()*gp.z() );
          float gpx = gp.x()/gp_mod;
          float gpy = gp.y()/gp_mod;
          float gpz = gp.z()/gp_mod;
          GlobalVector gv(gpx, gpy, gpz);

          // Make unit vectors in local coordinates and then transform them in global coordinates
          const Local3DVector lvx(1.0, 0.0, 0.0);
          GlobalVector gvx = theDet->surface().toGlobal( lvx );
          const Local3DVector lvy(0.0, 1.0, 0.0);
          GlobalVector gvy = theDet->surface().toGlobal( lvy );
          const Local3DVector lvz(0.0, 0.0, 1.0);
          GlobalVector gvz = theDet->surface().toGlobal( lvz );
          
          // Calculate angles alpha and beta
          float gv_dot_gvx = gv.x()*gvx.x() + gv.y()*gvx.y() + gv.z()*gvx.z();
          float gv_dot_gvy = gv.x()*gvy.x() + gv.y()*gvy.y() + gv.z()*gvy.z();
          float gv_dot_gvz = gv.x()*gvz.x() + gv.y()*gvz.y() + gv.z()*gvz.z();
          
          //float alpha_ = atan2( gv_dot_gvz, gv_dot_gvx );
          //float beta_  = atan2( gv_dot_gvz, gv_dot_gvy );
          
          cotalpha_ = gv_dot_gvx / gv_dot_gvz;
          cotbeta_  = gv_dot_gvy / gv_dot_gvz;
          
          


          // Attempt to get a better angle from tracks (either pixel tracks or full tracks)
          if ( !useStraightTracks_ )
        {
          // Use either pixel tracks (useTrajectories_ = False) or fully reconstructed tracks (useTrajectories_ = True)
          // When pixel/full tracks are not associated with the current cluster, will use angles from straight tracks
          
          // These are the tracks associated with this cluster
          std::vector<TrackAndState> vec_tracks_states = c.tracks;
          
          

          if ( (int)vec_tracks_states.size() > 0 )
            {
              //cout << "There is at least one track associated with this cluster. Pick the one with largest Pt." << endl;
              //cout << "(int)vec_tracks_states.size() = " << (int)vec_tracks_states.size() << endl;
              
              int index_max_pt = -99999;  // index of the track with the highest Pt
              float max_pt = -99999.9;
              
              for (int i=0; i<(int)vec_tracks_states.size(); ++i )
            {
              const reco::Track* one_track = vec_tracks_states[i].track;
              
              if ( one_track->pt() > max_pt )
                {
                  index_max_pt = i;
                  max_pt = one_track->pt();
                }  
            }
              
              // Pick the tsos from the track with highest Pt
              // gavril: Should we use highest Pt or best Chi2 ?
              TrajectoryStateOnSurface one_tsos = vec_tracks_states[index_max_pt].state;
              
              LocalTrajectoryParameters ltp = one_tsos.localParameters();
              
              LocalVector localDir = ltp.momentum()/ltp.momentum().mag();
              
              float locx = localDir.x();
              float locy = localDir.y();
              float locz = localDir.z();
              
              //alpha_ = atan2( locz, locx );
              //beta_  = atan2( locz, locy );
              
              cotalpha_ = locx/locz;
              cotbeta_  = locy/locz;
              
             
              
            } // if ( (int)vec_tracks_states.size() > 0 )
              
        } // if ( !useStraightTracks_ )

          // End: determine incident angles ============================================================


          
          //cout << "Calling qbin to see if the cluster has to be split..." << endl;          
              SiPixelTemplate templ_(thePixelTemp_);
              SiPixelTemplate2D templ2D_(thePixelTemp2D_);
          int templQbin_ = templ_.qbin( ID, cotalpha_, cotbeta_, thePixelCluster->charge() );

          if ( templQbin_ < 0 || templQbin_ > 5  )
        {
          // gavril : check this....
          // cout << "Template call failed. Cannot decide if cluster should be split !!!!!!! " << endl;
          // cout << "Do nothing." << endl;
        }
          else // if ( templQbin_ < 0 || templQbin_ > 5  ) {...} else
                {
          //cout << " Returned OK from PixelTempReco2D..." << endl;
          
          // Check for split clusters: we split the clusters with larger than expected charge: templQbin_ == 0 
          if ( templQbin_ != 0 ) 
            {
              // gavril: do not split this cluster
              //cout << "TEMPLATE SPLITTER SAYS : NO SPLIT " << endl;
              //cout << "This cluster will note be split !!!!!!!!!! " << endl; 
            }
          else // if ( templQbin_ != 0 ) {...} else
            {
              //cout << "TEMPLATE SPLITTER SAYS : SPLIT !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" << endl;
              //cout << "Found a cluster that has to be split. templQbin_ = " << templQbin_ << endl;
              
              // gavril: Call the template splitter
              //cout << "Calling the splitter..." << endl;
             
              // Put the pixels of this clusters in a 2x2 array to be used by the template splitter
              
              const std::vector<SiPixelCluster::Pixel> & pixVec = thePixelCluster->pixels();
              std::vector<SiPixelCluster::Pixel>::const_iterator pixIter = pixVec.begin(), pixEnd = pixVec.end();
              
              const int cluster_matrix_size_x = 13;
              const int cluster_matrix_size_y = 21;
              
              boost::multi_array<float, 2> clust_array_2d(boost::extents[cluster_matrix_size_x][cluster_matrix_size_y]);
              
              int row_offset = thePixelCluster->minPixelRow();
              int col_offset = thePixelCluster->minPixelCol();
              
              // Copy clust's pixels (calibrated in electrons) into clust_array_2d;
          
              for ( ; pixIter != pixEnd; ++pixIter ) 
            {
              int irow = int(pixIter->x) - row_offset;   // do we need +0.5 ???
              int icol = int(pixIter->y) - col_offset;   // do we need +0.5 ???
              
              if ( irow<cluster_matrix_size_x && icol<cluster_matrix_size_y )
                {
                  clust_array_2d[irow][icol] = (float)pixIter->adc;
                }
            }
              
              // Make and fill the bool arrays flagging double pixels
              std::vector<bool> ydouble(cluster_matrix_size_y), xdouble(cluster_matrix_size_x);
              
              // x directions (shorter), rows
              for (int irow = 0; irow < cluster_matrix_size_x; ++irow)
            {
              xdouble[irow] = theTopol->isItBigPixelInX( irow+row_offset );
            }
              
              // y directions (longer), columns
              for (int icol = 0; icol < cluster_matrix_size_y; ++icol) 
            {
              ydouble[icol] = theTopol->isItBigPixelInY( icol+col_offset );
            }

              // gavril: Initialize values coming back from SiPixelTemplateSplit::PixelTempSplit
              float templYrec1_  = -99999.9;
              float templYrec2_  = -99999.9;
              float templSigmaY_ = -99999.9;
              float templProbY_  = -99999.9;
              float templXrec1_  = -99999.9;
              float templXrec2_  = -99999.9;
              float templSigmaX_ = -99999.9;
              float templProbX_  = -99999.9;
              float dchisq       = -99999.9;
              float templProbQ_  = -99999.9;

              int ierr =
            SiPixelTemplateSplit::PixelTempSplit( ID, 
                                  cotalpha_, cotbeta_,
                                  clust_array_2d, 
                                  ydouble, xdouble,
                                  templ_,
                                  templYrec1_, templYrec2_, templSigmaY_, templProbY_,
                                  templXrec1_, templXrec2_, templSigmaX_, templProbX_,
                                  templQbin_, 
                                  templProbQ_, 
                                  true, 
                                  dchisq, 
                                  templ2D_ );
                
              if ( ierr != 0 )
            {
              // cout << "Cluster splitting failed: ierr = " << ierr << endl;
            }
              else
            {
              // gavril: Cluster was successfully split. 
              // gavril: Make the two split clusters and put them in the split cluster collection
              //cout << "Cluster splitting OK: ierr = " << ierr << endl;
              
              // 2D templates have origin at the lower left corner of template2d[1][1] which is 
              // also 2 pixels larger than the cluster container
              
              float xsize = templ_.xsize();  // this is the pixel x-size in microns
              float ysize = templ_.ysize();  // this is the pixel y-size in microns
              
              // Shift the coordinates to the 2-D template system             
              float yrecp1 = -99999.9;
              float yrecp2 = -99999.9;
              float xrecp1 = -99999.9;
              float xrecp2 = -99999.9;
              
              if ( ydouble[0] ) 
                {               
                  yrecp1 = templYrec1_ + ysize;
                  yrecp2 = templYrec2_ + ysize;
                } 
              else 
                {
                  yrecp1 = templYrec1_ + ysize/2.0;
                  yrecp2 = templYrec2_ + ysize/2.0;
                }
              
              if ( xdouble[0] ) 
                {
                  xrecp1 = templXrec1_ + xsize;
                  xrecp2 = templXrec2_ + xsize;
                } 
              else 
                {
                  xrecp1 = templXrec1_ + xsize/2.0;
                  xrecp2 = templXrec2_ + xsize/2.0;
                }
              
              //  The xytemp method adds charge to a zeroed buffer
              
              float template2d1[BXM2][BYM2];
              float template2d2[BXM2][BYM2];
              
              for ( int j=0; j<BXM2; ++j ) 
                {
                  for ( int i=0; i<BYM2; ++i ) 
                {
                  template2d1[j][i] = 0.0;
                  template2d2[j][i] = 0.0;
                }
                }
               
   
              bool template_OK 
                = templ2D_.xytemp(ID, cotalpha_, cotbeta_, 
                          xrecp1, yrecp1, 
                          ydouble, xdouble, 
                          template2d1);
              
              template_OK 
                = template_OK && 
                templ2D_.xytemp(ID, cotalpha_, cotbeta_, 
                        xrecp2, yrecp2, 
                        ydouble, xdouble, 
                        template2d2);
              
              if ( !template_OK ) 
                {
                  // gavril: check this
                  //cout << "Template is not OK. Fill out with zeros !!!!!!!!!!!!!!! " << endl; 
                  
                  for ( int j=0; j<BXM2; ++j ) 
                {
                  for ( int i=0; i<BYM2; ++i ) 
                    {
                      template2d1[j][i] = 0.0;
                      template2d2[j][i] = 0.0;
                    }
                }
                  
                  if ( !templ_.simpletemplate2D(xrecp1, yrecp1, 
                                xdouble, ydouble, 
                                template2d1) ) 
                {
                  cluster_was_successfully_split = false;
                }
                  
                  if ( !templ_.simpletemplate2D(xrecp2, yrecp2, 
                                xdouble, ydouble, 
                                template2d2) ) 
                {
                  cluster_was_successfully_split = false;
                }
                  
                } // if ( !template_OK ) 
              else
                {
                  cluster_was_successfully_split = true;
                  
                  // Next, copy the 2-d templates into cluster containers, replace small signals with zero.
                  // Cluster 1 and cluster 2 should line up with clust_array_2d (same origin and pixel indexing)
                  
                  float q50 = templ_.s50();
                  
                  
                  float cluster1[TXSIZE][TYSIZE];
                  float cluster2[TXSIZE][TYSIZE];  //Note that TXSIZE = BXM2 - 2, TYSIZE = BYM2 - 2
                  
                  for ( int j=0; j<TXSIZE; ++j ) 
                {
                  for ( int i=0; i<TYSIZE; ++i ) 
                    {
                      cluster1[j][i] = template2d1[j+1][i+1];
                      
                      if ( cluster1[j][i] < q50 ) 
                    cluster1[j][i] = 0.0;
                      
                      cluster2[j][i] = template2d2[j+1][i+1];
                      
                      if ( cluster2[j][i] < q50 ) 
                    cluster2[j][i] = 0.0;

                      //cout << "cluster1[j][i] = " << cluster1[j][i] << endl;
                      //cout << "cluster2[j][i] = " << cluster2[j][i] << endl;
                    }
                }
                
              
                  // Find the coordinates of first pixel in each of the two split clusters 
                  int i1 = -999;
                  int j1 = -999;
                  int i2 = -999;
                  int j2 = -999;
                                 
                  bool done_searching = false; 
                  for ( int i=0; i<13 && !done_searching; ++i)
                {
                  for (int j=0; j<21 && !done_searching; ++j)
                    {
                      if ( cluster1[i][j] > 0 )
                    {
                      i1 = i;
                      j1 = j;
                      done_searching = true;
                    }    
                    }
                }

                  done_searching = false; 
                  for ( int i=0; i<13 && !done_searching; ++i)
                {
                  for (int j=0; j<21 && !done_searching; ++j)
                    {
                      if ( cluster2[i][j] > 0 )
                    {
                      i2 = i;
                      j2 = j;
                      done_searching = true;
                    }
                    }
                }
                  
                  
                  // Make clusters out of the first pixels in each of the two split clsuters

                  SiPixelCluster cl1( SiPixelCluster::PixelPos( i1 + row_offset, j1 + col_offset), 
                          cluster1[i1][j1] );
                  
                  SiPixelCluster cl2( SiPixelCluster::PixelPos( i2 + row_offset, j2 + col_offset), 
                          cluster2[i2][j2] );
                  

                  // Now add the rest of the pixels to the split clusters

                  for ( int i=0; i<13; ++i)
                {
                  for (int j=0; j<21; ++j)
                    {
                      
                      if ( cluster1[i][j] > 0.0 && (i!=i1 || j!=j1 ) )
                    {
                      cl1.add( SiPixelCluster::PixelPos( i + row_offset, j + col_offset), 
                           cluster1[i][j] ); 

                      //cout << "cluster1[i][j] = " << cluster1[i][j] << endl;
                    }
                      
                      
                      if ( cluster2[i][j] > 0.0 && (i!=i2 || j!=j2 ) )
                    {                             
                      cl2.add( SiPixelCluster::PixelPos( i + row_offset, j + col_offset), 
                           cluster2[i][j] );
                      
                      //cout << "cluster2[i][j] = " << cluster2[i][j] << endl;
                    }
                    }
                }
                  
                  // Attach errors and probabilities to the split Clusters
                  // The errors will be later attahed to the SiPixelRecHit


                  cl1.setSplitClusterErrorX( templSigmaX_ );
                  cl1.setSplitClusterErrorY( templSigmaY_ );
                  //cl1.prob_q = templProbQ_;
                  
                  cl2.setSplitClusterErrorX( templSigmaX_ );
                  cl2.setSplitClusterErrorY( templSigmaY_ );
                  //cl2.prob_q = templProbQ_;


                  // Save the split clusters
                  output.push_back( cl1 );
                  output.push_back( cl2 );     
                 
                  // Some sanity checks

                  if ( (int)cl1.size() <= 0 )
                {
                  edm::LogError("TrackClusterSplitter : ") 
                    << "1) Cluster of size = " << (int)cl1.size() << " !!! " << endl;
                }

                  if ( (int)cl2.size() <= 0 )
                {
                  edm::LogError("TrackClusterSplitter : ") 
                    << "2) Cluster of size = " << (int)cl2.size() << " !!! " << endl;
                }

                  if ( cl1.charge() <= 0 )
                {
                  edm::LogError("TrackClusterSplitter : ") 
                    << "1) Cluster of charge = " << (int)cl1.charge() << " !!! " << endl;
                  
                }

                  if ( cl2.charge() <= 0 )
                {
                  edm::LogError("TrackClusterSplitter : ") 
                    << "2) Cluster of charge = " << (int)cl2.charge() << " !!!!!!!!!!!!!!!!!!!!!!!!!! " << endl;
                }
                  
                 
                } // if ( !template_OK ) ... else 
              
            } // if ( ierr2 != 0 ) ... else
              
            } // if ( templQbin_ != 0 ) ... else
          
        } // else // if ( templQbin_ < 0 || templQbin_ > 5  ) {...} else
          
        } // if ( (int)thePixelCluster->size() <= 1 ) {... } else
      
      if ( !cluster_was_successfully_split )
        output.push_back(*c.cluster);
      
    } // if ( theSiPixelCluster )
      else 
    {
      throw cms::Exception("TrackClusterSplitter :") 
        << "This is not a SiPixelCluster !!! " << "\n"; 
    }
    }
  else 
    {
      // gavril : Neither sim nor template splitter. Just add the cluster as it was.
      // original from G.P.
      output.push_back( *c.cluster );
    }
}

#include "FWCore/PluginManager/interface/ModuleDef.h"
#include "FWCore/Framework/interface/MakerMacros.h"
DEFINE_FWK_MODULE(TrackClusterSplitter);