/data/refman/pasoursint/CMSSW_5_3_0/src/RecoTauTag/ImpactParameter/src/ImpactParameterAlgorithm.cc

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#include "RecoTauTag/ImpactParameter/interface/ImpactParameterAlgorithm.h"

#include "RecoBTag/BTagTools/interface/SignedTransverseImpactParameter.h"
#include "RecoBTag/BTagTools/interface/SignedImpactParameter3D.h"

#include "TrackingTools/TransientTrack/interface/TransientTrackBuilder.h"

ImpactParameterAlgorithm::ImpactParameterAlgorithm(){
        ip_min   = -9999;
        ip_max   = 9999;
        sip_min  = 0;
        use_sign = false;
        use3D    = false; 
}

ImpactParameterAlgorithm::ImpactParameterAlgorithm(const edm::ParameterSet & parameters){
        ip_min       = parameters.getParameter<double>("TauImpactParameterMin");
        ip_max       = parameters.getParameter<double>("TauImpactParameterMax");
        sip_min      = parameters.getParameter<double>("TauImpactParameterSignificanceMin");
        use_sign     = parameters.getParameter<bool>("UseTauImpactParameterSign");
        use3D        = parameters.getParameter<bool>("UseTau3DImpactParameter");

}

void ImpactParameterAlgorithm::setTransientTrackBuilder(const TransientTrackBuilder * builder) { 
        transientTrackBuilder = builder; 
}


std::pair<float,reco::TauImpactParameterInfo> ImpactParameterAlgorithm::tag(const reco::IsolatedTauTagInfoRef & tauRef, const reco::Vertex & pv) {

        if(transientTrackBuilder == 0){
             std::cout << "Transient track builder is 0. abort!" << std::endl;
             abort(); //FIXME: trow an exception here
        }

        reco::TauImpactParameterInfo resultExtended;
        resultExtended.setIsolatedTauTag(tauRef);

        const reco::Jet* jet = tauRef->jet().get();
        GlobalVector direction(jet->px(),jet->py(),jet->pz());

        const reco::TrackRefVector& tracks = tauRef->selectedTracks();

        edm::RefVector<reco::TrackCollection>::const_iterator iTrack;
        for(iTrack = tracks.begin(); iTrack!= tracks.end(); iTrack++){

          const reco::TransientTrack transientTrack = (transientTrackBuilder->build(&(**iTrack)));

          SignedTransverseImpactParameter stip;
          Measurement1D ip = stip.apply(transientTrack,direction,pv).second;

          SignedImpactParameter3D signed_ip3D;
          Measurement1D ip3D = signed_ip3D.apply(transientTrack,direction,pv).second;
          //std::cout << "check pv,ip3d,track z " << pv.z() << " " << ip3D.value() << " " << transientTrack->dz() << std::endl;
          if(!use_sign){
            Measurement1D tmp2D(fabs(ip.value()),ip.error());
            ip = tmp2D;

            Measurement1D tmp3D(fabs(ip3D.value()),ip3D.error());
            ip3D = tmp3D;
          }

          reco::TauImpactParameterTrackData theData;

          theData.transverseIp = ip;
          theData.ip3D = ip3D;
          resultExtended.storeTrackData(*iTrack,theData);

        }

        float discriminator = resultExtended.discriminator(ip_min,ip_max,sip_min,use_sign,use3D);

        return std::make_pair( discriminator, resultExtended );
}