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"
#include "FWCore/MessageLogger/interface/MessageLogger.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 == nullptr) {
    throw cms::Exception("NullTransientTrackBuilder") << "Transient track builder is 0. ";
  }

  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;
    LogDebug("ImpactParameterAlgorithm::tag") << "check pv,ip3d " << pv.z() << " " << ip3D.value();
    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);
}