/data/refman/pasoursint/CMSSW_6_1_1/src/RecoVertex/TrimmedKalmanVertexFinder/src/ConfigurableTrimmedVertexFinder.cc

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#include "RecoVertex/TrimmedKalmanVertexFinder/interface/ConfigurableTrimmedVertexFinder.h"
#include "CommonTools/Statistics/interface/ChiSquaredProbability.h"

using namespace reco;

ConfigurableTrimmedVertexFinder::ConfigurableTrimmedVertexFinder(
  const VertexFitter<5> * vf, 
  const VertexUpdator<5> * vu, 
  const VertexTrackCompatibilityEstimator<5> * ve) 
  : theClusterFinder(vf, vu, ve), theVtxFitProbCut(0.01), 
    theTrackCompatibilityToPV(0.05), theTrackCompatibilityToSV(0.01), 
    theMaxNbOfVertices(0)
{
  // default pt cut is 1.5 GeV
  theFilter.setPtCut(1.5);
}

void ConfigurableTrimmedVertexFinder::setParameters ( const edm::ParameterSet & s )
{
  theFilter.setPtCut(s.getParameter<double>("ptCut"));
  theTrackCompatibilityToPV = s.getParameter<double>("trackCompatibilityToPVcut");
  theTrackCompatibilityToSV = s.getParameter<double>("trackCompatibilityToSVcut");
  theVtxFitProbCut = s.getParameter<double>("vtxFitProbCut"); 
  theMaxNbOfVertices =  s.getParameter<int>("maxNbOfVertices");
}


std::vector<TransientVertex> ConfigurableTrimmedVertexFinder::vertices(
  const std::vector<TransientTrack> & tracks) const
{
  std::vector<TransientTrack> remaining;

  return vertices(tracks, remaining, reco::BeamSpot(), false );

}

std::vector<TransientVertex> ConfigurableTrimmedVertexFinder::vertices(
  const std::vector<TransientTrack> & tracks, const reco::BeamSpot & spot ) const
{
  std::vector<TransientTrack> remaining;
  return vertices ( tracks, remaining, spot, true );
}

std::vector<TransientVertex> ConfigurableTrimmedVertexFinder::vertices(
  const std::vector<TransientTrack> & tracks, std::vector<TransientTrack> & unused,
  const reco::BeamSpot & spot, bool use_spot ) const
{
  resetEvent(tracks);
  analyseInputTracks(tracks);

  std::vector<TransientTrack> filtered;
  for (std::vector<TransientTrack>::const_iterator it = tracks.begin();
       it != tracks.end(); it++) {
    if (theFilter(*it)) { 
      filtered.push_back(*it);
    }
    else {
      unused.push_back(*it);
    }
  }

  std::vector<TransientVertex> all = vertexCandidates(filtered, unused,
      spot, use_spot );

  analyseVertexCandidates(all);

  std::vector<TransientVertex> sel = clean(all);

  analyseFoundVertices(sel);

  return sel;

}


std::vector<TransientVertex> ConfigurableTrimmedVertexFinder::vertexCandidates(
  const std::vector<TransientTrack> & tracks, std::vector<TransientTrack> & unused,
  const reco::BeamSpot & spot, bool use_spot ) const 
{

  std::vector<TransientVertex> cand;

  std::vector<TransientTrack> remain = tracks;

  while (true) {

    float tkCompCut = (cand.size() == 0 ? 
                       theTrackCompatibilityToPV 
                       : theTrackCompatibilityToSV);

    //    std::cout << "PVR:compat cut " << tkCompCut << std::endl;
    theClusterFinder.setTrackCompatibilityCut(tkCompCut);
    //    std::cout << "PVCF:compat cut after setting " 
    //   << theClusterFinder.trackCompatibilityCut() << std::endl;

    std::vector<TransientVertex> newVertices;
    if ( cand.size() == 0 && use_spot )
    {
      newVertices = theClusterFinder.vertices(remain, spot );
    } else {
      newVertices = theClusterFinder.vertices(remain);
    }
    if (newVertices.empty()) break;

    analyseClusterFinder(newVertices, remain);
    
    for (std::vector<TransientVertex>::const_iterator iv = newVertices.begin();
         iv != newVertices.end(); iv++) {
      if ( iv->originalTracks().size() > 1 ) {
        cand.push_back(*iv);
      } 
      else {
        // candidate has too few tracks - get them back into the vector
        for ( std::vector< TransientTrack >::const_iterator trk
                = iv->originalTracks().begin();
              trk != iv->originalTracks().end(); ++trk ) {
          unused.push_back ( *trk );
        }
      }
    }

    // when max number of vertices reached, stop
    if (theMaxNbOfVertices != 0) {
      if (cand.size() >= (unsigned int) theMaxNbOfVertices) break;
    }
  }

  for (std::vector<TransientTrack>::const_iterator it = remain.begin();
       it != remain.end(); it++) {
    unused.push_back(*it);
  }

  return cand;
}


std::vector<TransientVertex> 
ConfigurableTrimmedVertexFinder::clean(const std::vector<TransientVertex> & candidates) const
{
  std::vector<TransientVertex> sel;
  for (std::vector<TransientVertex>::const_iterator i = candidates.begin(); 
       i != candidates.end(); i++) {

    if (ChiSquaredProbability((*i).totalChiSquared(), (*i).degreesOfFreedom())
        > theVtxFitProbCut) { sel.push_back(*i); }
  }

  return sel;
}