/data/refman/pasoursint/CMSSW_5_3_0/src/RecoLocalTracker/SubCollectionProducers/src/TrackClusterSplitter.cc

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#include "FWCore/Framework/interface/Frameworkfwd.h"
#include "FWCore/Framework/interface/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>
using namespace std;

class TrackClusterSplitter : public edm::EDProducer 
{

public:
  TrackClusterSplitter(const edm::ParameterSet& iConfig) ;
  ~TrackClusterSplitter() ;
  void produce(edm::Event &iEvent, const edm::EventSetup &iSetup) ;
  
private:
  edm::InputTag stripClusters_;
  edm::InputTag pixelClusters_;
  
  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::InputTag trajectories_;  

  // This is the pixel primary vertex collection
  edm::InputTag vertices_;
  
  // 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
  mutable SiPixelTemplate         templ_  ;
  mutable SiPixelTemplate2D       templ2D_; 
  // Strip template
  mutable SiStripTemplate   strip_templ_  ;

  // 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* 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 false; 
  }
  
  // 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::auto_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):
  stripClusters_(iConfig.getParameter<edm::InputTag>("stripClusters")),
  pixelClusters_(iConfig.getParameter<edm::InputTag>("pixelClusters")),
  useTrajectories_(iConfig.getParameter<bool>("useTrajectories")),
  trajectories_(iConfig.getParameter<edm::InputTag>(useTrajectories_ ? "trajTrackAssociations" : "tracks")),
  vertices_(iConfig.getParameter<edm::InputTag>("vertices"))
{
  if ( !useTrajectories_ ) 
    propagatorName_ = iConfig.getParameter<std::string>("propagator");
  
  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"));

  /*
    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
  templ_.pushfile( 40 );
  templ_.pushfile( 41 );
  templ2D_.pushfile( 40 );
  templ2D_.pushfile( 41 );

  // Load strip templates
  strip_templ_.pushfile( 11 );
  strip_templ_.pushfile( 12 );
  strip_templ_.pushfile( 13 );
  strip_templ_.pushfile( 14 );
  strip_templ_.pushfile( 15 );
  strip_templ_.pushfile( 16 );

}


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.getByLabel(pixelClusters_, inputPixelClusters);
  
  iEvent.getByLabel(stripClusters_, inputStripClusters);
  
  if(simSplitStrip_)
    hitAssociator = new TrackerHitAssociator(iEvent);

    
  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.getByLabel(trajectories_, 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->get();
              if ( hit == 0 || !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.getByLabel(trajectories_, 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->get();
              if ( hit == 0 || !hit->isValid() ) 
                continue;
              
              int subdet = hit->geographicalId().subdetId();

              if ( subdet == 0 ) 
                continue;
              
              const GeomDet *det = geometry_->idToDet( hit->geographicalId() );
              
              if ( det == 0 ) 
                {
                  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.getByLabel(vertices_, vertices);
  
  // Needed in case of simsplit
  if ( simSplitPixel_ )
    iEvent.getByLabel("simSiPixelDigis", pixeldigisimlink);
    
  // Needed in case of strip simsplit
  if ( simSplitStrip_ )
    iEvent.getByLabel("simSiStripDigis", stripdigisimlink);

  // gavril : to do: choose the best vertex here instead of just choosing the first one ? 
  std::auto_ptr<edmNew::DetSetVector<SiPixelCluster> > newPixelClusters( splitClusters( siPixelDetsWithClusters, vertices->front() ) );
  std::auto_ptr<edmNew::DetSetVector<SiStripCluster> > newStripClusters( splitClusters( siStripDetsWithClusters, vertices->front() ) );
  
  if ( simSplitStrip_ )
    delete hitAssociator;

  iEvent.put(newPixelClusters);
  iEvent.put(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::auto_ptr<edmNew::DetSetVector<Cluster> > 
TrackClusterSplitter::splitClusters(const std::map<uint32_t, boost::sub_range<std::vector<ClusterWithTracks<Cluster> > > > &input, 
                                    const reco::Vertex &vtx) const 
{
  std::auto_ptr<edmNew::DetSetVector<Cluster> > output(new 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 == 0 ) 
        { 
          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();
      std::vector<uint8_t> 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();
                          currentAmpl = rawAmpl;
                        }
                      
                      // 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( detId, 
                                                        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].size() > 0  ) 
                    { 
                      // 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;          
              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( detId.rawId(), 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( detId.rawId(), 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());
      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();
    }
  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;              
              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);