#include <RecoVertex/KineExample/src/KineExample.cc>

Inheritance diagram for KineExample:

Public Member Functions
virtual void	analyze (const edm::Event &, const edm::EventSetup &)
virtual void	beginJob ()
virtual void	endJob ()
	KineExample (const edm::ParameterSet &)
	~KineExample ()
Private Member Functions
TrackingVertex	getSimVertex (const edm::Event &iEvent) const
void	printout (const RefCountedKinematicParticle &myParticle) const
void	printout (const RefCountedKinematicTree &myTree) const
void	printout (const RefCountedKinematicVertex &myVertex) const
Private Attributes
TrackAssociatorByChi2 *	associatorForParamAtPca
edm::ParameterSet	kvfPSet
std::string	outputFile_
edm::ParameterSet	theConfig
std::string	trackLabel_

Detailed Description

This is a very simple test analyzer mean to test the KalmanVertexFitter

Description: steers tracker primary vertex reconstruction and storage

Implementation: <Notes on="" implementation>="">

Definition at line 46 of file KineExample.h.

Constructor & Destructor Documentation

KineExample::KineExample ( const edm::ParameterSet & iConfig ) [explicit]

Definition at line 36 of file KineExample.cc.

References edm::ParameterSet::getParameter(), edm::ParameterSet::getUntrackedParameter(), kvfPSet, outputFile_, and trackLabel_.

  : theConfig(iConfig)
{
  trackLabel_ = iConfig.getParameter<std::string>("TrackLabel");
  outputFile_ = iConfig.getUntrackedParameter<std::string>("outputFile");
  kvfPSet = iConfig.getParameter<edm::ParameterSet>("KVFParameters");
//   rootFile_ = TFile::Open(outputFile_.c_str(),"RECREATE");
  edm::LogInfo("RecoVertex/KineExample")
    << "Initializing KVF TEST analyser  - Output file: " << outputFile_ <<"\n";
}

KineExample::~KineExample ( )

Definition at line 48 of file KineExample.cc.

                          {
//   delete rootFile_;
}

Member Function Documentation

void KineExample::analyze	(	const edm::Event &	iEvent,
		const edm::EventSetup &	iSetup
	)		`[virtual]`

Implements edm::EDAnalyzer.

Definition at line 70 of file KineExample.cc.

References gather_cfg::cout, exception, KinematicConstrainedVertexFitter::fit(), KinematicParticleVertexFitter::fit(), KinematicParticleFitter::fit(), edm::EventSetup::get(), edm::Event::getByLabel(), edm::EventBase::id(), edm::HandleBase::isValid(), TransientVertex::isValid(), jpsi, KinematicParticleFactoryFromTransientTrack::particle(), TransientVertex::position(), printout(), trackLabel_, and KalmanVertexFitter::vertex().

{
  try {

  cout << "Reconstructing event number: " << iEvent.id() << "\n";

  // get RECO tracks from the event
  // `tks` can be used as a ptr to a reco::TrackCollection
  edm::Handle<reco::TrackCollection> tks;
  iEvent.getByLabel(trackLabel_, tks);
  if (!tks.isValid()) {
    cout
      << "Couln't find track collection: " << iEvent.id()
      << "\n";
  } else {

    edm::LogInfo("RecoVertex/KineExample")
      << "Found: " << (*tks).size() << " reconstructed tracks" << "\n";
    cout << "got " << (*tks).size() << " tracks " << endl;

    // Transform Track to TransientTrack
    //get the builder:
    edm::ESHandle<TransientTrackBuilder> theB;
    iSetup.get<TransientTrackRecord>().get("TransientTrackBuilder",theB);
    //do the conversion:
    vector<TransientTrack> t_tks = (*theB).build(tks);

     cout  << "Found: " << t_tks.size() << " reconstructed tracks" << "\n";

    // Do a KindFit, if >= 4 tracks.
    if (t_tks.size() > 3) {

      // For a first test, suppose that the first four tracks are the 2 muons,
      // then the 2 kaons. Since this will not be true, the result of the fit
      // will not be meaningfull, but at least you will get the idea of how to
      // do such a fit.

      //First, to get started, a simple vertex fit:

      vector<TransientTrack> ttv;
      ttv.push_back(t_tks[0]); ttv.push_back(t_tks[1]); ttv.push_back(t_tks[2]);ttv.push_back(t_tks[3]);
      KalmanVertexFitter kvf(false);
      TransientVertex tv = kvf.vertex(ttv);
      if (!tv.isValid()) cout << "KVF failed\n";
      else std::cout << "KVF fit Position: " << Vertex::Point(tv.position()) << "\n";


      TransientTrack ttMuPlus = t_tks[0];
      TransientTrack ttMuMinus = t_tks[1];
      TransientTrack ttKPlus = t_tks[2];
      TransientTrack ttKMinus = t_tks[3];

      //the final state muons and kaons from the Bs->J/PsiPhi->mumuKK decay
      //Creating a KinematicParticleFactory
      KinematicParticleFactoryFromTransientTrack pFactory;

      //The mass of a muon and the insignificant mass sigma to avoid singularities in the covariance matrix.
      ParticleMass muon_mass = 0.1056583;
      ParticleMass kaon_mass = 0.493677;
      float muon_sigma = 0.0000001;
      float kaon_sigma = 0.000016;

      //initial chi2 and ndf before kinematic fits. The chi2 of the reconstruction is not considered
      float chi = 0.;
      float ndf = 0.;

      //making particles
      vector<RefCountedKinematicParticle> muonParticles;
      vector<RefCountedKinematicParticle> phiParticles;
      vector<RefCountedKinematicParticle> allParticles;
      muonParticles.push_back(pFactory.particle (ttMuPlus,muon_mass,chi,ndf,muon_sigma));
      muonParticles.push_back(pFactory.particle (ttMuMinus,muon_mass,chi,ndf,muon_sigma));
      allParticles.push_back(pFactory.particle (ttMuPlus,muon_mass,chi,ndf,muon_sigma));
      allParticles.push_back(pFactory.particle (ttMuMinus,muon_mass,chi,ndf,muon_sigma));

      phiParticles.push_back(pFactory.particle (ttKPlus,kaon_mass,chi,ndf,kaon_sigma));
      phiParticles.push_back(pFactory.particle (ttKMinus,kaon_mass,chi,ndf,kaon_sigma));
      allParticles.push_back(pFactory.particle (ttKPlus,kaon_mass,chi,ndf,kaon_sigma));
      allParticles.push_back(pFactory.particle (ttKMinus,kaon_mass,chi,ndf,kaon_sigma));

      /* Example of a simple vertex fit, without other constraints
       * The reconstructed decay tree is a result of the kinematic fit
       * The KinematicParticleVertexFitter fits the final state particles to their vertex and
       * reconstructs the decayed state
       */
      KinematicParticleVertexFitter fitter;
      cout <<"Simple vertex fit with KinematicParticleVertexFitter:\n";
      RefCountedKinematicTree vertexFitTree = fitter.fit(allParticles);

      printout(vertexFitTree);


        //creating the constraint for the J/Psi mass
        ParticleMass jpsi = 3.09687;

        //creating the two track mass constraint
        MultiTrackKinematicConstraint *  j_psi_c = new  TwoTrackMassKinematicConstraint(jpsi);

        //creating the fitter
        KinematicConstrainedVertexFitter kcvFitter;

        //obtaining the resulting tree
        RefCountedKinematicTree myTree = kcvFitter.fit(allParticles, j_psi_c);

        cout << "\nGlobal fit done:\n";
        printout(myTree);

        //creating the vertex fitter
        KinematicParticleVertexFitter kpvFitter;

        //reconstructing a J/Psi decay
        RefCountedKinematicTree jpTree = kpvFitter.fit(muonParticles);

        //creating the particle fitter
        KinematicParticleFitter csFitter;

        // creating the constraint
        float jp_m_sigma = 0.00004;
        KinematicConstraint * jpsi_c2 = new MassKinematicConstraint(jpsi,jp_m_sigma);

        //the constrained fit:
        jpTree = csFitter.fit(jpsi_c2,jpTree);

        //getting the J/Psi KinematicParticle and putting it together with the kaons.
        //The J/Psi KinematicParticle has a pointer to the tree it belongs to
        jpTree->movePointerToTheTop();
        RefCountedKinematicParticle jpsi_part = jpTree->currentParticle();
        phiParticles.push_back(jpsi_part);

        //making a vertex fit and thus reconstructing the Bs parameters
        // the resulting tree includes all the final state tracks, the J/Psi meson,
        // its decay vertex, the Bs meson and its decay vertex.
        RefCountedKinematicTree bsTree = kpvFitter.fit(phiParticles);
        cout << "Sequential fit done:\n";
        printout(bsTree);



//       // For the analysis: compare to your SimVertex
//       TrackingVertex sv = getSimVertex(iEvent);
//   edm::Handle<TrackingParticleCollection>  TPCollectionH ;
//   iEvent.getByLabel("trackingtruth","TrackTruth",TPCollectionH);
//   const TrackingParticleCollection tPC = *(TPCollectionH.product());
//       reco::RecoToSimCollection recSimColl=associatorForParamAtPca->associateRecoToSim(tks,
//                                                                            TPCollectionH,
//                                                                            &iEvent);
//
//       tree->fill(tv, &sv, &recSimColl);
//     }

    }
  }

  }
  catch (std::exception & err) {
    cout  << "Exception during event number: " << iEvent.id()
      << "\n" << err.what() << "\n";
  }

}

void KineExample::beginJob ( void ) [virtual]

Reimplemented from edm::EDAnalyzer.

Definition at line 52 of file KineExample.cc.

References associatorForParamAtPca, edm::ESHandle< T >::product(), and HcalObjRepresent::setup().

                          {
  edm::ESHandle<TrackAssociatorBase> theAssociatorForParamAtPca;
  setup.get<TrackAssociatorRecord>().get("TrackAssociatorByChi2",theAssociatorForParamAtPca);
  associatorForParamAtPca = (TrackAssociatorByChi2 *) theAssociatorForParamAtPca.product();

//   tree = new SimpleVertexTree("VertexFitter", associatorForParamAtPca);
}

void KineExample::endJob ( void ) [virtual]

Reimplemented from edm::EDAnalyzer.

Definition at line 61 of file KineExample.cc.

                         {
//   delete tree;
}

TrackingVertex KineExample::getSimVertex ( const edm::Event & iEvent ) const [private]

Definition at line 288 of file KineExample.cc.

References edm::Event::getByLabel(), and edm::Handle< T >::product().

{
   // get the simulated vertices
  edm::Handle<TrackingVertexCollection>  TVCollectionH ;
  iEvent.getByLabel("trackingtruth","VertexTruth",TVCollectionH);
  const TrackingVertexCollection tPC = *(TVCollectionH.product());

//    Handle<edm::SimVertexContainer> simVtcs;
//    iEvent.getByLabel("g4SimHits", simVtcs);
//    std::cout << "SimVertex " << simVtcs->size() << std::endl;
//    for(edm::SimVertexContainer::const_iterator v=simVtcs->begin();
//        v!=simVtcs->end(); ++v){
//      std::cout << "simvtx "
//             << v->position().x() << " "
//             << v->position().y() << " "
//             << v->position().z() << " "
//             << v->parentIndex() << " "
//             << v->noParent() << " "
//               << std::endl;
//    }
   return *(tPC.begin());
}

void KineExample::printout ( const RefCountedKinematicVertex & myVertex ) const [private]

Definition at line 232 of file KineExample.cc.

References gather_cfg::cout.

Referenced by analyze(), and printout().

{
  if (myVertex->vertexIsValid()) {
    cout << "Decay vertex: " << myVertex->position() <<myVertex->chiSquared()<< " "<<myVertex->degreesOfFreedom()<<endl;
  } else cout << "Decay vertex Not valid\n";
}

void KineExample::printout ( const RefCountedKinematicTree & myTree ) const [private]

Definition at line 251 of file KineExample.cc.

References gather_cfg::cout, i, and printout().

{
  if (!myTree->isValid()) {
    cout <<"Tree is invalid. Fit failed.\n";
    return;
  }

//accessing the tree components, move pointer to top
  myTree->movePointerToTheTop();

//We are now at the top of the decay tree getting the B_s reconstructed KinematicPartlcle
  RefCountedKinematicParticle b_s = myTree->currentParticle();
  printout(b_s);

// The B_s decay vertex
  RefCountedKinematicVertex b_dec_vertex = myTree->currentDecayVertex();
  printout(b_dec_vertex);

  // Get all the children of Bs:
  //In this way, the pointer is not moved
  vector< RefCountedKinematicParticle > bs_children = myTree->finalStateParticles();

  for (unsigned int i=0;i< bs_children.size();++i) {
    printout(bs_children[i]);
  }

//Now navigating down the tree , pointer is moved:
  bool child = myTree->movePointerToTheFirstChild();

  if(child) while (myTree->movePointerToTheNextChild()) {
    RefCountedKinematicParticle aChild = myTree->currentParticle();
    printout(aChild);
  }
}

void KineExample::printout ( const RefCountedKinematicParticle & myParticle ) const [private]

Definition at line 239 of file KineExample.cc.

References gather_cfg::cout.

{
  cout << "Particle: \n";
//accessing the reconstructed Bs meson parameters:
  AlgebraicVector7 bs_par = myParticle->currentState().kinematicParameters().vector();

//and their joint covariance matrix:
  AlgebraicSymMatrix77 bs_er = myParticle->currentState().kinematicParametersError().matrix();
  cout << "Momentum at vertex: " << myParticle->currentState().globalMomentum ()<<endl;
  cout << "Parameters at vertex: " << myParticle->currentState().kinematicParameters().vector()<<endl;
}