/afs/cern.ch/work/a/aaltunda/public/www/CMSSW_6_2_5/src/RecoMuon/StandAloneTrackFinder/src/ExhaustiveMuonTrajectoryBuilder.cc

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#include "RecoMuon/StandAloneTrackFinder/interface/ExhaustiveMuonTrajectoryBuilder.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "RecoMuon/TrackingTools/interface/MuonServiceProxy.h"
#include "RecoMuon/TransientTrackingRecHit/interface/MuonTransientTrackingRecHitBuilder.h"


ExhaustiveMuonTrajectoryBuilder::ExhaustiveMuonTrajectoryBuilder(const edm::ParameterSet & pset, 
                                                         const MuonServiceProxy* proxy)
: theTrajBuilder(pset, proxy),
  theSeeder(),
  theService(proxy)
{
}


ExhaustiveMuonTrajectoryBuilder::~ExhaustiveMuonTrajectoryBuilder() {}


MuonTrajectoryBuilder::TrajectoryContainer 
ExhaustiveMuonTrajectoryBuilder::trajectories(const TrajectorySeed& seed)
{
  LocalTrajectoryParameters localTrajectoryParameters(seed.startingState().parameters());
  LocalVector p(localTrajectoryParameters.momentum());
  int rawId = seed.startingState().detId();
  DetId detId(rawId);
  bool isBarrel = (detId.subdetId() == 1);
  // homemade local-to-global
  double pt = (isBarrel) ? -p.z() : p.perp();
  pt *= localTrajectoryParameters.charge();
  float err00 = seed.startingState().error(0);
  //   float p_err = sqr(sptmean/(ptmean*ptmean));
  //  mat[0][0]= p_err;
  float sigmapt = sqrt(err00)*pt*pt;
  TrajectorySeed::range range = seed.recHits();
  TrajectoryContainer result;
  // Make a new seed based on each segment, using the original pt and sigmapt
  for(TrajectorySeed::const_iterator recHitItr = range.first;
      recHitItr != range.second; ++recHitItr)
  {
    const GeomDet * geomDet = theService->trackingGeometry()->idToDet((*recHitItr).geographicalId());
    MuonTransientTrackingRecHit::MuonRecHitPointer muonRecHit 
      = MuonTransientTrackingRecHit::specificBuild(geomDet,&*recHitItr);
    TrajectorySeed tmpSeed(theSeeder.createSeed(pt, sigmapt, muonRecHit));
    TrajectoryContainer trajectories(theTrajBuilder.trajectories(tmpSeed));
    result.insert(result.end(), trajectories.begin(), trajectories.end());
  }
  // choose the best trajectory
  if(!result.empty()) clean(result);
  return result;
}


MuonTrajectoryBuilder::CandidateContainer 
ExhaustiveMuonTrajectoryBuilder::trajectories(const TrackCand&)
{
  return CandidateContainer();
}



void ExhaustiveMuonTrajectoryBuilder::setEvent(const edm::Event& event)
{
  theTrajBuilder.setEvent(event);
}


void ExhaustiveMuonTrajectoryBuilder::clean(TrajectoryContainer & trajectories) const
{
  // choose the one with the most hits, and the smallest chi-squared
  int best_nhits = 0;
  unsigned best = 0;
  unsigned ntraj = trajectories.size();
  for(unsigned i = 0; i < ntraj; ++i)
  {
    int nhits = trajectories[i]->foundHits();
    if(nhits > best_nhits)
    {
      best_nhits = nhits;
      best = i;
    }
    else if(nhits == best_nhits && trajectories[i]->chiSquared() < trajectories[best]->chiSquared())
    {
      best = i;
    }
  }
  TrajectoryContainer result;
  for(unsigned i = 0; i < ntraj; ++i)
  {
    if(i == best) {
      result.push_back(trajectories[best]);
    } else {
       delete trajectories[i];
    }
  }
  trajectories.swap(result);
}