Trk::FastVertexFitter Class Reference

This class implements a fast vertex fitting algorithm as proposed by P. More...

#include <FastVertexFitter.h>

Inheritance diagram for Trk::FastVertexFitter:

Collaboration diagram for Trk::FastVertexFitter:

Public Member Functions
virtual StatusCode	initialize () override
	FastVertexFitter (const std::string &t, const std::string &n, const IInterface *p)
virtual	~FastVertexFitter ()
	standard destructor More...
virtual xAOD::Vertex *	fit (const std::vector< const Trk::TrackParameters * > &perigeeList, const Amg::Vector3D &startingPoint) const override
	Interface for ParametersBase with starting point. More...
virtual xAOD::Vertex *	fit (const std::vector< const TrackParameters * > &perigeeList, const std::vector< const Trk::NeutralParameters * > &, const Amg::Vector3D &startingPoint) const override
	Interface for TrackParameters and NeutralParameters with starting point. More...
virtual xAOD::Vertex *	fit (const std::vector< const Trk::TrackParameters * > &perigeeList, const xAOD::Vertex &constraint) const override
	Interface for ParametersBase with vertex constraint. More...
virtual xAOD::Vertex *	fit (const std::vector< const TrackParameters * > &perigeeList, const std::vector< const Trk::NeutralParameters * > &, const xAOD::Vertex &constraint) const override
	Interface for TrackParameters and NeutralParameters with RecVertex starting point. More...
virtual xAOD::Vertex *	fit (const std::vector< const Trk::TrackParameters * > &perigeeList) const override
	Fit interface with no starting point or constraint. More...
virtual xAOD::Vertex *	fit (const std::vector< const TrackParameters * > &perigeeList, const std::vector< const Trk::NeutralParameters * > &) const override
virtual xAOD::Vertex *	fit (const std::vector< const xAOD::TrackParticle * > &vectorTrk, const Amg::Vector3D &startingPoint) const override
	*Interface for xAOD::TrackParticle with starting point More...
virtual xAOD::Vertex *	fit (const std::vector< const xAOD::TrackParticle * > &vectorTrk, const std::vector< const xAOD::NeutralParticle * > &, const Amg::Vector3D &startingPoint) const override
	*Interface for xAOD::TrackParticle and NeutralParticle with starting point More...
virtual xAOD::Vertex *	fit (const std::vector< const xAOD::TrackParticle * > &vectorTrk, const xAOD::Vertex &constraint) const override
virtual xAOD::Vertex *	fit (const std::vector< const xAOD::TrackParticle * > &vectorTrk, const std::vector< const xAOD::NeutralParticle * > &, const xAOD::Vertex &constraint) const override

Private Attributes
unsigned int	m_maxIterations
double	m_maxDchi2PerNdf
ToolHandle< Trk::IExtrapolator >	m_extrapolator {this, "Extrapolator", "Trk::Extrapolator"}
ToolHandle< Trk::IVertexLinearizedTrackFactory >	m_linFactory {this, "LinearizedTrackFactory", "Trk::FullLinearizedTrackFactory"}

Detailed Description

This class implements a fast vertex fitting algorithm as proposed by P.

Billoir. this algorithm tries to estimate the vertex position without refitting the track parameters. It therefore only needs to vary two of five perigee parameters (namely d0, z0) to estimate the vertex position.

Changes:

David Shope david.nosp@m..ric.nosp@m.hard..nosp@m.shop.nosp@m.e@cer.nosp@m.n.ch (2016-04-19)

EDM Migration to xAOD - from Trk::VxCandidate to xAOD::Vertex, from Trk::RecVertex to xAOD::Vertex, from Trk::Vertex to Amg::Vector3D

Definition at line 38 of file FastVertexFitter.h.

Constructor & Destructor Documentation

FastVertexFitter()

Trk::FastVertexFitter::FastVertexFitter	(	const std::string &	t,
		const std::string &	n,
		const IInterface *	p
	)

Definition at line 82 of file FastVertexFitter.cxx.

                                                                                                      : base_class ( t,n,p ),
                                                          m_maxIterations ( 3 ),
                                                          m_maxDchi2PerNdf ( 0.000001 )
                                                          
                                                          
    {
      declareProperty ( "MaxIterations",        m_maxIterations );
      declareProperty ( "MaxChi2PerNdf",        m_maxDchi2PerNdf );
      declareInterface<IVertexFitter> ( this );
    }

~FastVertexFitter()

Trk::FastVertexFitter::~FastVertexFitter ( )

virtualdefault

standard destructor

Member Function Documentation

fit() [1/10]

virtual xAOD::Vertex* Trk::FastVertexFitter::fit ( const std::vector< const TrackParameters * > &  perigeeList, const std::vector< const Trk::NeutralParameters * > &    ) const

inlineoverridevirtual

Definition at line 100 of file FastVertexFitter.h.

  {
    msg(MSG::WARNING) << "FastVertexFitter::fit(fit(const std::vector<const "
                         "TrackParameters*>&,const std::vector<const "
                         "Trk::NeutralParameters*>&) ignoring neutrals"
                      << endmsg;
    return fit(perigeeList);
  };

fit() [2/10]

virtual xAOD::Vertex* Trk::FastVertexFitter::fit ( const std::vector< const TrackParameters * > &  perigeeList, const std::vector< const Trk::NeutralParameters * > &  , const Amg::Vector3D &  startingPoint  ) const

inlineoverridevirtual

Interface for TrackParameters and NeutralParameters with starting point.

Definition at line 59 of file FastVertexFitter.h.

  {
    msg(MSG::WARNING)
      << "FastVertexFitter::fit(fit(const std::vector<const "
         "TrackParameters*>&,const std::vector<const "
         "Trk::NeutralParameters*>&,const Amg::Vector3D&) ignoring neutrals"
      << endmsg;
    return fit(perigeeList, startingPoint);
  };

fit() [3/10]

virtual xAOD::Vertex* Trk::FastVertexFitter::fit ( const std::vector< const TrackParameters * > &  perigeeList, const std::vector< const Trk::NeutralParameters * > &  , const xAOD::Vertex &  constraint  ) const

inlineoverridevirtual

Interface for TrackParameters and NeutralParameters with RecVertex starting point.

Definition at line 80 of file FastVertexFitter.h.

  {
    msg(MSG::WARNING)
      << "FastVertexFitter::fit(fit(const std::vector<const "
         "TrackParameters*>&,const std::vector<const "
         "Trk::NeutralParameters*>&,const xAOD::Vertex&) ignoring neutrals"
      << endmsg;
    return fit(perigeeList, constraint);
  };

fit() [4/10]

xAOD::Vertex * Trk::FastVertexFitter::fit ( const std::vector< const Trk::TrackParameters * > &  perigeeList ) const

overridevirtual

Fit interface with no starting point or constraint.

(0,0,0) will be assumed.

Definition at line 335 of file FastVertexFitter.cxx.

    {
        Amg::Vector3D tmpVtx(0.,0.,0.);
        return fit ( perigeeList, tmpVtx );
    }

fit() [5/10]

xAOD::Vertex * Trk::FastVertexFitter::fit ( const std::vector< const Trk::TrackParameters * > &  originalPerigees, const Amg::Vector3D &  firstStartingPoint  ) const

overridevirtual

Interface for ParametersBase with starting point.

Interface for Track with vertex constraint.

the position of the constraint is ALWAYS the starting point Interface for MeasuredPerigee with starting point

Definition at line 100 of file FastVertexFitter.cxx.

    {
                xAOD::Vertex constraint;
                constraint.makePrivateStore();
                constraint.setPosition( firstStartingPoint );
                constraint.setCovariancePosition( AmgSymMatrix(3)::Zero(3,3) );
                constraint.setFitQuality( 0.,0.);
        return fit ( originalPerigees, constraint );
    }

fit() [6/10]

xAOD::Vertex * Trk::FastVertexFitter::fit ( const std::vector< const Trk::TrackParameters * > &  originalPerigees, const xAOD::Vertex &  firstStartingPoint  ) const

overridevirtual

Interface for ParametersBase with vertex constraint.

Interface for MeasuredPerigee with vertex constraint.

the position of the constraint is ALWAYS the starting point

Definition at line 113 of file FastVertexFitter.cxx.

    {
        if ( originalPerigees.empty() )
        {
            ATH_MSG_VERBOSE("No tracks to fit in this event.");
            return nullptr;
        }
 
        /* Initialisation of variables */
        double chi2 = 2000000000000.;
        unsigned int nRP = originalPerigees.size();  // Number of tracks to fit
        int ndf = nRP * ( 5-3 ) - 3;                 // Number of degrees of freedom
        if ( ndf == -1 ) ndf = 1;
 
        /* Determine if we are doing a constraint fit.*/
        bool constraint = false;
        if ( firstStartingPoint.covariancePosition().trace() != 0. )
        {
            constraint = true;
            ndf += 3;
            ATH_MSG_DEBUG("Fitting with constraint.");
            ATH_MSG_VERBOSE(firstStartingPoint.covariancePosition().inverse().eval());
        }
 
        double chi2New=0.;double chi2Old=0.;
 
        Amg::Vector3D linPoint ( firstStartingPoint.position() ); // linearization point for track parameters (updated for every iteration)
 
        auto fittedVertex = std::make_unique<xAOD::Vertex>();
                fittedVertex->makePrivateStore(); // xAOD::VertexContainer will take ownership of AuxStore when ActualVertex is added to it
 
        std::vector<VxTrackAtVertex> tracksAtVertex;
        std::vector<BilloirTrack> billoirTracks;
 
        /* Iterate fits until the fit criteria are met, or the number of max
        iterations is reached. */
        for ( unsigned int niter=0; niter < m_maxIterations; ++niter )
        {
            // msg(MSG::VERBOSE) << "Start of iteration " << niter << ", starting point ("
            // << linPoint [0] << ", " << linPoint [1] << ", " << linPoint [2]
            // << ") and " << originalPerigees.size() << " tracks." << endmsg;
 
            billoirTracks.clear();
            chi2Old = chi2New;
            chi2New = 0.;
 
            AmgMatrix(2,3) D;
 
            /* Linearize the track parameters wrt. starting point of the fit */
            Amg::Vector3D globalPosition = linPoint;
            Trk::PerigeeSurface perigeeSurface ( globalPosition );
 
            BilloirVertex billoirVertex;
                        // unsigned int count(0);
            for (const auto *originalPerigee : originalPerigees)
            {
                LinearizedTrack* linTrack = m_linFactory->linearizedTrack ( originalPerigee, linPoint );
                if ( linTrack==nullptr )
                {
                    ATH_MSG_DEBUG("Could not linearize track! Skipping this track!");
                }
                else
                {
                    // local position
                    Amg::Vector3D locXpVec = linTrack->expectedPositionAtPCA();
                    locXpVec[0] = locXpVec[0] - linPoint[0];
                    locXpVec[1] = locXpVec[1] - linPoint[1];
                    locXpVec[2] = locXpVec[2] - linPoint[2];
                    
                    // msg(MSG::VERBOSE) << "Track: " << count << endmsg;
                    // count++;
                    // const Trk::MeasuredPerigee* tmpPerigee = dynamic_cast<const Trk::MeasuredPerigee*>(*iter);
                    //AmgVector(5) expParameters = linTrack->expectedParametersAtPCA();
                    
                    // msg(MSG::VERBOSE) << "locXp: " << locXpVec[0] << "\t" << locXpVec[1] << "\t" << locXpVec[2] << endmsg;
 
                    // first get the cov 2x2 sub matrix and then invert (don't get the 2x2 sub matrix of the 5x5 already inverted cov matrix)
                    AmgMatrix(2,2) billoirCovMat = linTrack->expectedCovarianceAtPCA().block<2,2>(0,0);
                    // msg(MSG::VERBOSE) << "CovMatrix: " << billoirCovMat[0][0] << "\t" << billoirCovMat[0][1] << endmsg;
                    // msg(MSG::VERBOSE) << "           " << billoirCovMat[1][0] << "\t" << billoirCovMat[1][1] << endmsg;
                    AmgMatrix(2,2) billoirWeightMat = billoirCovMat.inverse().eval();
                    // msg(MSG::VERBOSE) << "WeightMatrix: " << billoirWeightMat[0][0] << "\t" << billoirWeightMat[0][1] << endmsg;
                    // msg(MSG::VERBOSE) << "              " << billoirWeightMat[1][0] << "\t" << billoirWeightMat[1][1] << endmsg;
                    // D matrix for d0 and z0
                    D = linTrack->positionJacobian().block<2,3>(0,0);
                    // msg(MSG::VERBOSE) << "DMatrix:      " << D[0][0] << "\t" << D[0][1] << endmsg;
                    // msg(MSG::VERBOSE) << "              " << D[1][0] << "\t" << D[1][1] << endmsg;
 
                    // Calculate DtWD and DtWD*x and sum them
                    BilloirTrack locBilloirTrack;
                    locBilloirTrack.xpVec = locXpVec;
                    locBilloirTrack.DtWD = (D.transpose())*billoirWeightMat*D; 
                    locBilloirTrack.chi2 = -1.0; 
                    billoirVertex.DtWD_Sum += locBilloirTrack.DtWD;
                    locBilloirTrack.DtWDx = ((D.transpose())*billoirWeightMat*D)*locXpVec;
                    billoirVertex.DtWDx_Sum += locBilloirTrack.DtWDx;
                    locBilloirTrack.originalPerigee = originalPerigee;
                    billoirTracks.push_back ( locBilloirTrack );
                }
                    delete linTrack; linTrack=nullptr;
            }
            if ( billoirTracks.empty() )
            {
                ATH_MSG_DEBUG("No linearized tracks left after linearization! Should not happen!");
                return nullptr;
            }
            if ( constraint )
            {
                // add V_del += wgtconst * (linPoint.position() - Vconst) and V_wgt +=wgtconst
                Amg::Vector3D constraintPosInBilloirFrame;
                constraintPosInBilloirFrame.setZero();
                // this will be 0 for first iteration but != 0 from second on
                constraintPosInBilloirFrame[0] = firstStartingPoint.position() [0]-linPoint [0];
                constraintPosInBilloirFrame[1] = firstStartingPoint.position() [1]-linPoint [1];
                constraintPosInBilloirFrame[2] = firstStartingPoint.position() [2]-linPoint [2];
                billoirVertex.DtWDx_Sum += firstStartingPoint.covariancePosition().inverse().eval() *constraintPosInBilloirFrame;
                billoirVertex.DtWD_Sum  += firstStartingPoint.covariancePosition().inverse().eval();
            }
 
            AmgMatrix(3,3) cov_delta_V_mat = billoirVertex.DtWD_Sum.inverse( ) ;
 
            Amg::Vector3D delta_V = cov_delta_V_mat * billoirVertex.DtWDx_Sum;
 
            std::vector<BilloirTrack>::iterator BTIter;
            for ( BTIter = billoirTracks.begin(); BTIter != billoirTracks.end() ; ++BTIter )
            {
                // calculate chi2PerTrack = (xpVec - vtxPosInBilloirFrame).T * DtWD(track) * (xpVec - vtxPosInBilloirFrame); )
                Amg::Vector3D diff;
                diff.setZero();
                diff[0] = ( *BTIter ).xpVec[0] - delta_V[0];
                diff[1] = ( *BTIter ).xpVec[1] - delta_V[1];
                diff[2] = ( *BTIter ).xpVec[2] - delta_V[2];
                ( *BTIter ).chi2 = diff.dot(( *BTIter ).DtWD* diff );
                if ( ( *BTIter ).chi2 < 0 )
                {
                    std::cout << "VxFastFit::calculate: error in chi2_per_track: "<<( *BTIter ).chi2<<"\n";
                    return nullptr;
                }
                chi2New += ( *BTIter ).chi2;
            }
 
            if ( constraint )
            {
                Amg::Vector3D deltaTrk;
                deltaTrk.setZero();
                // last term will also be 0 again but only in the first iteration
                //                  = calc. vtx in billoir frame - (    constraint pos. in billoir frame    )
                deltaTrk[0] = delta_V[0]                 - ( firstStartingPoint.position() [0] - linPoint [0] );
                deltaTrk[1] = delta_V[1]                 - ( firstStartingPoint.position() [1] - linPoint [1] );
                deltaTrk[2] = delta_V[2]                 - ( firstStartingPoint.position() [2] - linPoint [2] );
                chi2New += Amg::chi2(firstStartingPoint.covariancePosition().inverse().eval(), deltaTrk);
            }
 
            /* assign new linearization point (= new vertex position in global frame) */
            Amg::Vector3D tmpPos ( linPoint );
            tmpPos[0] += delta_V[0];   tmpPos[1] += delta_V[1];   tmpPos[2] += delta_V[2];
            linPoint = tmpPos;
 
            // msg(MSG::VERBOSE) << "Vertex of Iteration " << niter << " with chi2: " << chi2New << "\t old chi2: " << chi2 << endmsg;
            // msg(MSG::VERBOSE) << "deltaV: ("    << delta_V[0] << ", " << delta_V[1] << ", " << delta_V[2] << ")" << endmsg;
            // msg(MSG::VERBOSE) << linPoint << endmsg;
 
            if ( chi2New < chi2 )
            {
                /* Store the vertex */
                chi2 = chi2New;
                //const AmgMatrix(3,3) * newCovarianceMatrix = &cov_delta_V_mat ;
                //const AmgMatrix(3,3) newErrorMatrix = newCovarianceMatrix->inverse().eval();
                //fittedVertex = RecVertex ( linPoint.position(), newErrorMatrix, ndf, chi2 );
 
                                // The cov_delta_V_mat does not need to be inverted.  -katy 2/3/16
                fittedVertex->setPosition( linPoint );
                fittedVertex->setCovariancePosition( cov_delta_V_mat );
                fittedVertex->setFitQuality( chi2, ndf );
 
                /* new go through vector and delete entries */
                /* // TODO: not needed anymore, tracksAtVertex doesn't store pointers - just the objects themselves <David Shope> (EDM Migration) 03/21/16
                for ( std::vector<Trk::VxTrackAtVertex*>::const_iterator itr = tracksAtVertex.begin();
                        itr != tracksAtVertex.end(); ++itr )
                {
                    delete ( *itr );
                }
                */
 
                tracksAtVertex.clear();
 
                Amg::Vector3D pointToExtrapolateTo ( linPoint [0], linPoint [1], linPoint [2] );
                Trk::PerigeeSurface perigeeSurface ( pointToExtrapolateTo );
                for ( BTIter = billoirTracks.begin(); BTIter != billoirTracks.end() ; ++BTIter )
                {
                    // you need to extrapolate the original perigee ((*BTIter).originalPerigee) really to the
                    // found vertex. The first propagation above is only to the starting point. But here we
                    // want to store it wrt. to the last fitted vertex
                    auto extrapolatedPerigee = std::unique_ptr<const Trk::TrackParameters> ( m_extrapolator->extrapolate ( 
              Gaudi::Hive::currentContext(), 
              * ( *BTIter ).originalPerigee, 
              perigeeSurface ) );
                    if ( extrapolatedPerigee==nullptr )
                    {
                        extrapolatedPerigee = std::unique_ptr<const Trk::TrackParameters>(((*BTIter).originalPerigee)->clone());
                        ATH_MSG_DEBUG("Could not extrapolate these track parameters to final vertex position! Storing original position as final one ...");
                    }
          //VxTrackAtVertex will own the clone of the extrapolatedPerigee
                    Trk::VxTrackAtVertex* tmpVxTrkAtVtx = new Trk::VxTrackAtVertex ( ( *BTIter ).chi2, extrapolatedPerigee->clone(), 
                                                                           ( *BTIter ).originalPerigee ) ;
                    tracksAtVertex.push_back ( *tmpVxTrkAtVtx );
                    // TODO: here is where the vxTracksAtVertex pointers are deleted
                    delete tmpVxTrkAtVtx; // TODO: is this ok?
                }
            }
 
            if ( fabs ( chi2Old-chi2New ) < m_maxDchi2PerNdf * ndf )
            {
                break;
            }
        } // end of iteration
        fittedVertex->vxTrackAtVertex() = tracksAtVertex;
        //ATH_MSG_VERBOSE("Final Vertex Fitted: " << fittedVxCandidate->recVertex()); // TODO: can no longer print vertex after converting to xAOD
        return fittedVertex.release();
    }

fit() [7/10]

xAOD::Vertex * Trk::FastVertexFitter::fit ( const std::vector< const xAOD::TrackParticle * > &  vectorTrk, const Amg::Vector3D &  startingPoint  ) const

overridevirtual

*Interface for xAOD::TrackParticle with starting point

Definition at line 343 of file FastVertexFitter.cxx.

         {
                  xAOD::Vertex constraint;
                  constraint.makePrivateStore();
                  constraint.setPosition( startingPoint );
                  constraint.setCovariancePosition( AmgSymMatrix(3)::Zero(3,3) );
                  constraint.setFitQuality( 0.,0.);
          return fit(vectorTrk, constraint);                                
         }//end of the xAOD starting point fit method 

fit() [8/10]

virtual xAOD::Vertex* Trk::FastVertexFitter::fit ( const std::vector< const xAOD::TrackParticle * > &  vectorTrk, const std::vector< const xAOD::NeutralParticle * > &  , const Amg::Vector3D &  startingPoint  ) const

inlineoverridevirtual

*Interface for xAOD::TrackParticle and NeutralParticle with starting point

Definition at line 119 of file FastVertexFitter.h.

  {
    msg(MSG::WARNING)
      << "FastVertexFitter::fit(fit(const std::vector<const "
         "TrackParticle*>&,const std::vector<const "
         "Trk::NeutralParticle*>&,const Amg::Vector3D&) ignoring neutrals"
      << endmsg;
    return fit(vectorTrk, startingPoint);
  };

fit() [9/10]

virtual xAOD::Vertex* Trk::FastVertexFitter::fit ( const std::vector< const xAOD::TrackParticle * > &  vectorTrk, const std::vector< const xAOD::NeutralParticle * > &  , const xAOD::Vertex &  constraint  ) const

inlineoverridevirtual

• Interface for xAOD::TrackParticle and NeutralParticle with vertex constraint the position of the constraint is ALWAYS the starting point
  

Definition at line 141 of file FastVertexFitter.h.

  {
    msg(MSG::WARNING)
      << "FastVertexFitter::fit(fit(const std::vector<const "
         "TrackParticle*>&,const std::vector<const "
         "Trk::NeutralParticle*>&,const xAOD::Vertex&) ignoring neutrals"
      << endmsg;
    return fit(vectorTrk, constraint);
  };

fit() [10/10]

xAOD::Vertex * Trk::FastVertexFitter::fit ( const std::vector< const xAOD::TrackParticle * > &  vectorTrk, const xAOD::Vertex &  constraint  ) const

overridevirtual

• Interface for xAOD::TrackParticle with vertex constraint the position of the constraint is ALWAYS the starting point
  

Definition at line 354 of file FastVertexFitter.cxx.

         { 
           if(vectorTrk.empty()) 
           { 
            msg(MSG::INFO)<<"Empty vector of tracks passed"<<endmsg; 
            return nullptr; 
           } 
            
           //making a list of perigee out of the vector of tracks   
           std::vector<const Trk::TrackParameters*> measuredPerigees; 
            
           for(const auto *i : vectorTrk) 
           { 
            const Trk::TrackParameters * tmpMeasPer = &(i->perigeeParameters()); 
           
            if(tmpMeasPer!=nullptr) measuredPerigees.push_back(tmpMeasPer); 
            else  msg(MSG::INFO)<<"Failed to dynamic_cast this track parameters to perigee"<<endmsg; //TODO: Failed to implicit cast the perigee parameters to track parameters?
           } 
            
            
           xAOD::Vertex* fittedVertex = fit( measuredPerigees, constraint ); 
           // fit() may return nullptr, need to protect 
           if (fittedVertex == nullptr){
                ATH_MSG_WARNING("Failed fit, returning null vertex"); 
                return nullptr; 
           }
           //assigning the input tracks to the fitted vertex through VxTrackAtVertices
           { 
            if( fittedVertex->vxTrackAtVertexAvailable() ) // TODO: I don't think vxTrackAtVertexAvailable() does the same thing as a null pointer check!
                                                                                            // Regretful Hindsight 8 years later: No, it doesn't! 
            { 
             if(!fittedVertex->vxTrackAtVertex().empty()) 
             { 
              for(unsigned int i = 0; i <vectorTrk.size(); ++i) 
              { 
         
               LinkToXAODTrackParticle * linkTT = new LinkToXAODTrackParticle; 
               linkTT->setElement(vectorTrk[i]); 
         
               // vxtrackatvertex takes ownership! 
               ( fittedVertex->vxTrackAtVertex() )[i].setOrigTrack(linkTT); 
              }//end of loop for setting orig tracks in. 
             }//end of protection against unsuccessfull updates (no tracks were added) 
            }//end of vector of tracks check 
           }//end of pointer check 
 
                   //now set links to xAOD::TrackParticles directly in the xAOD::Vertex
                   unsigned int VTAVsize = fittedVertex->vxTrackAtVertex().size();
                   for (unsigned int i = 0 ; i < VTAVsize ; ++i)
                   {
                     Trk::VxTrackAtVertex* VTAV = &( fittedVertex->vxTrackAtVertex().at(i) );
                     //TODO: Will this pointer really hold 0 if no VxTrackAtVertex is found?
                     if (not VTAV){
                       ATH_MSG_WARNING (" Trying to set link to xAOD::TrackParticle. The VxTrackAtVertex is not found");
                       continue;
                     }
 
                     Trk::ITrackLink* trklink = VTAV->trackOrParticleLink();
 
                     // See if the trklink is to an xAOD::TrackParticle
                     Trk::LinkToXAODTrackParticle* linkToXAODTP = dynamic_cast<Trk::LinkToXAODTrackParticle*>(trklink);
                     if (linkToXAODTP)
                     {
 
                       //Now set the new link to the xAOD vertex
                       fittedVertex->addTrackAtVertex(*linkToXAODTP, VTAV->weight());
 
                     } else {
                       ATH_MSG_WARNING ("Skipping track. Trying to set link to something else than xAOD::TrackParticle. Neutrals not supported.");
                     }
                   } //end of loop
 
           return fittedVertex;
 
         }//end of the xAOD constrained fit method 

initialize()

StatusCode Trk::FastVertexFitter::initialize ( )

overridevirtual

Definition at line 55 of file FastVertexFitter.cxx.

    {
 
        if ( m_extrapolator.retrieve().isFailure() )
        {
            msg(MSG::FATAL) << "Failed to retrieve tool " << m_extrapolator << endmsg;
            return StatusCode::FAILURE;
        }
        
        
            msg(MSG::INFO) << "Retrieved tool " << m_extrapolator << endmsg;
        
 
        if ( m_linFactory.retrieve().isFailure() )
        {
            msg(MSG::FATAL) << "Failed to retrieve tool " << m_linFactory << endmsg;
            return StatusCode::FAILURE;
        }
        
        
            msg(MSG::INFO) << "Retrieved tool " << m_linFactory << endmsg;
        
 
        return StatusCode::SUCCESS;
    }

Member Data Documentation

m_extrapolator

ToolHandle<Trk::IExtrapolator> Trk::FastVertexFitter::m_extrapolator {this, "Extrapolator", "Trk::Extrapolator"}

private

Definition at line 158 of file FastVertexFitter.h.

m_linFactory

ToolHandle<Trk::IVertexLinearizedTrackFactory> Trk::FastVertexFitter::m_linFactory {this, "LinearizedTrackFactory", "Trk::FullLinearizedTrackFactory"}

private

Definition at line 159 of file FastVertexFitter.h.

m_maxDchi2PerNdf

double Trk::FastVertexFitter::m_maxDchi2PerNdf

private

Definition at line 156 of file FastVertexFitter.h.

m_maxIterations

unsigned int Trk::FastVertexFitter::m_maxIterations

private

Definition at line 155 of file FastVertexFitter.h.

---

The documentation for this class was generated from the following files:

• FastVertexFitter.h
• FastVertexFitter.cxx