RecoTauConstructor.cc

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#include "RecoTauTag/RecoTau/interface/RecoTauConstructor.h"

#include "RecoTauTag/RecoTau/interface/RecoTauCommonUtilities.h"
#include "DataFormats/Common/interface/RefToPtr.h"

#include "DataFormats/Math/interface/deltaR.h"

#include "RecoTauTag/RecoTau/interface/pfRecoTauChargedHadronAuxFunctions.h"

namespace reco::tau {

RecoTauConstructor::RecoTauConstructor(const JetBaseRef& jet, const edm::Handle<edm::View<reco::Candidate> >& pfCands, 
                       bool copyGammasFromPiZeros,
                       const StringObjectFunction<reco::PFTau>* signalConeSize,
                       double minAbsPhotonSumPt_insideSignalCone, double minRelPhotonSumPt_insideSignalCone,
                       double minAbsPhotonSumPt_outsideSignalCone, double minRelPhotonSumPt_outsideSignalCone)
  : signalConeSize_(signalConeSize),
    minAbsPhotonSumPt_insideSignalCone_(minAbsPhotonSumPt_insideSignalCone),
    minRelPhotonSumPt_insideSignalCone_(minRelPhotonSumPt_insideSignalCone),
    minAbsPhotonSumPt_outsideSignalCone_(minAbsPhotonSumPt_outsideSignalCone),
    minRelPhotonSumPt_outsideSignalCone_(minRelPhotonSumPt_outsideSignalCone),
    pfCands_(pfCands)
{
  // Initialize tau
  tau_.reset(new PFTau());

  copyGammas_ = copyGammasFromPiZeros;
  // Initialize our Accessors
  collections_[std::make_pair(kSignal, kChargedHadron)] =
      &tau_->selectedSignalChargedHadrCands_;
  collections_[std::make_pair(kSignal, kGamma)] =
      &tau_->selectedSignalGammaCands_;
  collections_[std::make_pair(kSignal, kNeutralHadron)] =
      &tau_->selectedSignalNeutrHadrCands_;
  collections_[std::make_pair(kSignal, kAll)] =
      &tau_->selectedSignalCands_;

  collections_[std::make_pair(kIsolation, kChargedHadron)] =
      &tau_->selectedIsolationChargedHadrCands_;
  collections_[std::make_pair(kIsolation, kGamma)] =
      &tau_->selectedIsolationGammaCands_;
  collections_[std::make_pair(kIsolation, kNeutralHadron)] =
      &tau_->selectedIsolationNeutrHadrCands_;
  collections_[std::make_pair(kIsolation, kAll)] =
      &tau_->selectedIsolationCands_;

  // Build our temporary sorted collections, since you can't use stl sorts on
  // RefVectors
  for(auto const& colkey : collections_) {
    // Build an empty list for each collection
    sortedCollections_[colkey.first] = SortedListPtr(
        new SortedListPtr::element_type);
  }

  tau_->setjetRef(jet);
}

void RecoTauConstructor::addPFCand(Region region, ParticleType type, const CandidatePtr& ptr, bool skipAddToP4) {
  LogDebug("TauConstructorAddPFCand") << " region = " << region << ", type = " << type << ": Pt = " << ptr->pt() << ", eta = " << ptr->eta() << ", phi = " << ptr->phi();
  if ( region == kSignal ) {
    // Keep track of the four vector of the signal vector products added so far.
    // If a photon add it if we are not using PiZeros to build the gammas
    if ( ((type != kGamma) || !copyGammas_) && !skipAddToP4 ) {
      LogDebug("TauConstructorAddPFCand") << "--> adding PFCand to tauP4." ;
      p4_ += ptr->p4();
    }
  }
  getSortedCollection(region, type)->push_back(ptr);
  // Add to global collection
  getSortedCollection(region, kAll)->push_back(ptr);
}

void RecoTauConstructor::reserve(Region region, ParticleType type, size_t size){
  getSortedCollection(region, type)->reserve(size);
  getCollection(region, type)->reserve(size);
  // Reserve global collection as well
  getSortedCollection(region, kAll)->reserve(
      getSortedCollection(region, kAll)->size() + size);
  getCollection(region, kAll)->reserve(
      getCollection(region, kAll)->size() + size);
}

void RecoTauConstructor::reserveTauChargedHadron(Region region, size_t size) 
{
  if ( region == kSignal ) {
    tau_->signalTauChargedHadronCandidatesRestricted().reserve(size);
    tau_->selectedSignalChargedHadrCands_.reserve(size);
  } else {
    tau_->isolationTauChargedHadronCandidatesRestricted().reserve(size);
    tau_->selectedIsolationChargedHadrCands_.reserve(size);
  }
}

namespace
{
  void checkOverlap(const CandidatePtr& neutral, const std::vector<CandidatePtr>& pfGammas, bool& isUnique)
  {
    LogDebug("TauConstructorCheckOverlap") << " pfGammas: #entries = " << pfGammas.size();
    for ( std::vector<CandidatePtr>::const_iterator pfGamma = pfGammas.begin();
      pfGamma != pfGammas.end(); ++pfGamma ) {
      LogDebug("TauConstructorCheckOverlap") << "pfGamma = " << pfGamma->id() << ":" << pfGamma->key();
      if ( (*pfGamma).refCore() == neutral.refCore() && (*pfGamma).key() == neutral.key() ) isUnique = false;
    }
  }


  void checkOverlap(const CandidatePtr& neutral, const std::vector<reco::RecoTauPiZero>& piZeros, bool& isUnique)
  {
    LogDebug("TauConstructorCheckOverlap") << " piZeros: #entries = " << piZeros.size();
    for ( std::vector<reco::RecoTauPiZero>::const_iterator piZero = piZeros.begin();
      piZero != piZeros.end(); ++piZero ) {
      size_t numPFGammas = piZero->numberOfDaughters();
      for ( size_t iPFGamma = 0; iPFGamma < numPFGammas; ++iPFGamma ) {
    reco::CandidatePtr pfGamma = piZero->daughterPtr(iPFGamma);
    LogDebug("TauConstructorCheckOverlap") << "pfGamma = " << pfGamma.id() << ":" << pfGamma.key();
    if ( pfGamma.id() == neutral.id() && pfGamma.key() == neutral.key() ) isUnique = false;
      }
    }
  }
}

void RecoTauConstructor::addTauChargedHadron(Region region, const PFRecoTauChargedHadron& chargedHadron) 
{
  LogDebug("TauConstructorAddChH") << " region = " << region << ": Pt = " << chargedHadron.pt() << ", eta = " << chargedHadron.eta() << ", phi = " << chargedHadron.phi();
  // CV: need to make sure that PFGammas merged with ChargedHadrons are not part of PiZeros
  const std::vector<CandidatePtr>& neutrals = chargedHadron.getNeutralPFCandidates();
  std::vector<CandidatePtr> neutrals_cleaned;
  for ( std::vector<CandidatePtr>::const_iterator neutral = neutrals.begin();
    neutral != neutrals.end(); ++neutral ) {
    LogDebug("TauConstructorAddChH") << "neutral = " << neutral->id() << ":" << neutral->key();
    bool isUnique = true;
    if ( copyGammas_ ) checkOverlap(*neutral, *getSortedCollection(kSignal, kGamma), isUnique);
    else checkOverlap(*neutral, tau_->signalPiZeroCandidatesRestricted(), isUnique);
    if ( region == kIsolation ) {
      if ( copyGammas_ ) checkOverlap(*neutral, *getSortedCollection(kIsolation, kGamma), isUnique);
      else checkOverlap(*neutral, tau_->isolationPiZeroCandidatesRestricted(), isUnique);      
    }
    LogDebug("TauConstructorAddChH") << "--> isUnique = " << isUnique;
    if ( isUnique ) neutrals_cleaned.push_back(*neutral);
  }
  PFRecoTauChargedHadron chargedHadron_cleaned = chargedHadron;
  if ( neutrals_cleaned.size() != neutrals.size() ) {
    chargedHadron_cleaned.neutralPFCandidates_ = neutrals_cleaned;
    setChargedHadronP4(chargedHadron_cleaned);
  }
  if ( region == kSignal ) {
    tau_->signalTauChargedHadronCandidatesRestricted().push_back(chargedHadron_cleaned);
    p4_ += chargedHadron_cleaned.p4();
    if ( chargedHadron_cleaned.getChargedPFCandidate().isNonnull() ) {
      addPFCand(kSignal, kChargedHadron, convertToPtr(chargedHadron_cleaned.getChargedPFCandidate()), true);
    }
    const std::vector<CandidatePtr>& neutrals = chargedHadron_cleaned.getNeutralPFCandidates();
    for ( std::vector<CandidatePtr>::const_iterator neutral = neutrals.begin();
      neutral != neutrals.end(); ++neutral ) {
      if      ( std::abs((*neutral)->pdgId()) == 22 ) addPFCand(kSignal, kGamma, convertToPtr(*neutral), true);
      else if ( std::abs((*neutral)->pdgId()) == 130 ) addPFCand(kSignal, kNeutralHadron, convertToPtr(*neutral), true);
    };
  } else {
    tau_->isolationTauChargedHadronCandidatesRestricted().push_back(chargedHadron_cleaned);
    if ( chargedHadron_cleaned.getChargedPFCandidate().isNonnull() ) {
      if      ( std::abs(chargedHadron_cleaned.getChargedPFCandidate()->pdgId()) == 211  ) addPFCand(kIsolation, kChargedHadron, convertToPtr(chargedHadron_cleaned.getChargedPFCandidate()));
      else if ( std::abs(chargedHadron_cleaned.getChargedPFCandidate()->pdgId()) == 130 ) addPFCand(kIsolation, kNeutralHadron, convertToPtr(chargedHadron_cleaned.getChargedPFCandidate()));
    }
    const std::vector<CandidatePtr>& neutrals = chargedHadron_cleaned.getNeutralPFCandidates();
    for ( std::vector<CandidatePtr>::const_iterator neutral = neutrals.begin();
      neutral != neutrals.end(); ++neutral ) {
      if      ( std::abs((*neutral)->pdgId()) == 22 ) addPFCand(kIsolation, kGamma, convertToPtr(*neutral));
      else if ( std::abs((*neutral)->pdgId()) == 130 ) addPFCand(kIsolation, kNeutralHadron, convertToPtr(*neutral));
    };
  }
}

void RecoTauConstructor::reservePiZero(Region region, size_t size) 
{
  if ( region == kSignal ) {
    tau_->signalPiZeroCandidatesRestricted().reserve(size);
    // If we are building the gammas with the pizeros, resize that
    // vector as well
    if ( copyGammas_ ) reserve(kSignal, kGamma, 2*size);
  } else {
    tau_->isolationPiZeroCandidatesRestricted().reserve(size);
    if ( copyGammas_ ) reserve(kIsolation, kGamma, 2*size);
  }
}

void RecoTauConstructor::addPiZero(Region region, const RecoTauPiZero& piZero) 
{
  LogDebug("TauConstructorAddPi0") << " region = " << region << ": Pt = " << piZero.pt() << ", eta = " << piZero.eta() << ", phi = " << piZero.phi();
  if ( region == kSignal ) {
    tau_->signalPiZeroCandidatesRestricted().push_back(piZero);
    // Copy the daughter gammas into the gamma collection if desired
    if ( copyGammas_ ) {
      // If we are using the pizeros to build the gammas, make sure we update
      // the four vector correctly.
      p4_ += piZero.p4();
      addPFCands(kSignal, kGamma, piZero.daughterPtrVector().begin(), 
          piZero.daughterPtrVector().end());
    }
  } else {
    tau_->isolationPiZeroCandidatesRestricted().push_back(piZero);
    if ( copyGammas_ ) {
      addPFCands(kIsolation, kGamma, piZero.daughterPtrVector().begin(),
          piZero.daughterPtrVector().end());
    }
  }
}

std::vector<CandidatePtr>*
RecoTauConstructor::getCollection(Region region, ParticleType type) {
    return collections_[std::make_pair(region, type)];
}

RecoTauConstructor::SortedListPtr
RecoTauConstructor::getSortedCollection(Region region, ParticleType type) {
  return sortedCollections_[std::make_pair(region, type)];
}

// Trivial converter needed for polymorphism
CandidatePtr RecoTauConstructor::convertToPtr(
    const CandidatePtr& pfPtr) const {
  return pfPtr;
}

namespace {
// Make sure the two products come from the same EDM source
template<typename T1, typename T2>
void checkMatchedProductIds(const T1& t1, const T2& t2) {
    if (t1.id() != t2.id()) {
      throw cms::Exception("MismatchedPFCandSrc") << "Error: the input tag"
          << " for the PF candidate collection provided to the RecoTauBuilder "
          << " does not match the one that was used to build the source jets."
          << " Please update the pfCandSrc paramters for the PFTau builders.";
    }
}
}

// Convert from a CandidateRef to a Ptr
CandidatePtr RecoTauConstructor::convertToPtr(
    const PFCandidatePtr& candPtr) const {
  if(candPtr.isNonnull()) {
    checkMatchedProductIds(candPtr, pfCands_);
    return CandidatePtr(pfCands_, candPtr.key());
  } else return PFCandidatePtr();
}

namespace {
template<typename T> bool ptDescending(const T& a, const T& b) {
  return a.pt() > b.pt();
}
template<typename T> bool ptDescendingPtr(const T& a, const T& b) {
  return a->pt() > b->pt();
}
}

void RecoTauConstructor::sortAndCopyIntoTau() {
  // The charged hadrons and pizeros are a special case, as we can sort them in situ
  std::sort(tau_->signalTauChargedHadronCandidatesRestricted().begin(),
            tau_->signalTauChargedHadronCandidatesRestricted().end(),
            ptDescending<PFRecoTauChargedHadron>);
  std::sort(tau_->isolationTauChargedHadronCandidatesRestricted().begin(),
            tau_->isolationTauChargedHadronCandidatesRestricted().end(),
            ptDescending<PFRecoTauChargedHadron>);
  std::sort(tau_->signalPiZeroCandidatesRestricted().begin(),
            tau_->signalPiZeroCandidatesRestricted().end(),
            ptDescending<RecoTauPiZero>);
  std::sort(tau_->isolationPiZeroCandidatesRestricted().begin(),
            tau_->isolationPiZeroCandidatesRestricted().end(),
            ptDescending<RecoTauPiZero>);

  // Sort each of our sortable collections, and copy them into the final
  // tau RefVector.
  for (auto const& colkey : collections_ ) {
    SortedListPtr sortedCollection = sortedCollections_[colkey.first];
    std::sort(sortedCollection->begin(),
              sortedCollection->end(),
              ptDescendingPtr<CandidatePtr>);
    // Copy into the real tau collection
    for ( std::vector<CandidatePtr>::const_iterator particle = sortedCollection->begin();
      particle != sortedCollection->end(); ++particle ) {
      colkey.second->push_back(*particle);
    }
  }
}

namespace
{
  PFTau::hadronicDecayMode calculateDecayMode(const reco::PFTau& tau, double dRsignalCone, 
                          double minAbsPhotonSumPt_insideSignalCone, double minRelPhotonSumPt_insideSignalCone,
                          double minAbsPhotonSumPt_outsideSignalCone, double minRelPhotonSumPt_outsideSignalCone) 
  {
    unsigned int nCharged = tau.signalTauChargedHadronCandidates().size();
    // If no tracks exist, this is definitely not a tau!
    if ( !nCharged ) return PFTau::kNull;

    unsigned int nPiZeros = 0;
    const std::vector<RecoTauPiZero>& piZeros = tau.signalPiZeroCandidates();
    for ( std::vector<RecoTauPiZero>::const_iterator piZero = piZeros.begin();
      piZero != piZeros.end(); ++piZero ) {
      double photonSumPt_insideSignalCone = 0.;
      double photonSumPt_outsideSignalCone = 0.;
      int numPhotons = piZero->numberOfDaughters();
      for ( int idxPhoton = 0; idxPhoton < numPhotons; ++idxPhoton ) {
    const reco::Candidate* photon = piZero->daughter(idxPhoton);
    double dR = deltaR(photon->p4(), tau.p4());
    if ( dR < dRsignalCone ) {
      photonSumPt_insideSignalCone += photon->pt();
    } else {
      photonSumPt_outsideSignalCone += photon->pt();
    }
      }
      if ( photonSumPt_insideSignalCone  > minAbsPhotonSumPt_insideSignalCone  || photonSumPt_insideSignalCone  > (minRelPhotonSumPt_insideSignalCone*tau.pt())  ||
       photonSumPt_outsideSignalCone > minAbsPhotonSumPt_outsideSignalCone || photonSumPt_outsideSignalCone > (minRelPhotonSumPt_outsideSignalCone*tau.pt()) ) ++nPiZeros;
    }
    
    // Find the maximum number of PiZeros our parameterization can hold
    const unsigned int maxPiZeros = PFTau::kOneProngNPiZero;
    
    // Determine our track index
    unsigned int trackIndex = (nCharged - 1)*(maxPiZeros + 1);
    
    // Check if we handle the given number of tracks
    if ( trackIndex >= PFTau::kRareDecayMode ) return PFTau::kRareDecayMode;
    
    if ( nPiZeros > maxPiZeros ) nPiZeros = maxPiZeros;
    return static_cast<PFTau::hadronicDecayMode>(trackIndex + nPiZeros);
  }
}

std::auto_ptr<reco::PFTau> RecoTauConstructor::get(bool setupLeadingObjects) 
{
  LogDebug("TauConstructorGet") << "Start getting" ;

  // Copy the sorted collections into the interal tau refvectors
  sortAndCopyIntoTau();

  // Setup all the important member variables of the tau
  // Set charge of tau
//  tau_->setCharge(
//      sumPFCandCharge(getCollection(kSignal, kChargedHadron)->begin(),
//                      getCollection(kSignal, kChargedHadron)->end()));
  // CV: take charge of highest pT charged hadron as charge of tau,
  //     in case tau does not have three reconstructed tracks
  //    (either because tau is reconstructed as 2prong or because PFRecoTauChargedHadron is built from a PFNeutralHadron)
  unsigned int nCharged = 0;
  int charge = 0;
  double leadChargedHadronPt = 0.;
  int leadChargedHadronCharge = 0;
  for ( std::vector<PFRecoTauChargedHadron>::const_iterator chargedHadron = tau_->signalTauChargedHadronCandidatesRestricted().begin();
    chargedHadron != tau_->signalTauChargedHadronCandidatesRestricted().end(); ++chargedHadron ) {
    if ( chargedHadron->algoIs(PFRecoTauChargedHadron::kChargedPFCandidate) || chargedHadron->algoIs(PFRecoTauChargedHadron::kTrack) ) {
      ++nCharged;
      charge += chargedHadron->charge();
      if ( chargedHadron->pt() > leadChargedHadronPt ) {    
    leadChargedHadronPt = chargedHadron->pt();
    leadChargedHadronCharge = chargedHadron->charge();
      }
    }
  }
  if ( nCharged == 3 ) tau_->setCharge(charge);
  else tau_->setCharge(leadChargedHadronCharge);

  // Set PDG id
  tau_->setPdgId(tau_->charge() < 0 ? 15 : -15);

  // Set P4
  tau_->setP4(p4_);

  // Set Decay Mode
  double dRsignalCone = ( signalConeSize_ ) ? (*signalConeSize_)(*tau_) : 0.5;
  tau_->setSignalConeSize(dRsignalCone);
  PFTau::hadronicDecayMode dm = calculateDecayMode(
      *tau_, 
      dRsignalCone, 
      minAbsPhotonSumPt_insideSignalCone_, minRelPhotonSumPt_insideSignalCone_, minAbsPhotonSumPt_outsideSignalCone_, minRelPhotonSumPt_outsideSignalCone_);
  tau_->setDecayMode(dm);

  LogDebug("TauConstructorGet") << "Pt = " << tau_->pt() << ", eta = " << tau_->eta() << ", phi = " << tau_->phi() << ", mass = " << tau_->mass() << ", dm = " << tau_->decayMode() ;

  // Set charged isolation quantities
  tau_->setisolationPFChargedHadrCandsPtSum(
      sumPFCandPt(
        getCollection(kIsolation, kChargedHadron)->begin(),
        getCollection(kIsolation, kChargedHadron)->end()));

  // Set gamma isolation quantities
  tau_->setisolationPFGammaCandsEtSum(
      sumPFCandPt(
        getCollection(kIsolation, kGamma)->begin(),
        getCollection(kIsolation, kGamma)->end()));

  // Set em fraction
  tau_->setemFraction(sumPFCandPt(
          getCollection(kSignal, kGamma)->begin(),
          getCollection(kSignal, kGamma)->end()) / tau_->pt());

  if ( setupLeadingObjects ) {
    typedef std::vector<CandidatePtr>::const_iterator Iter;
    // Find the highest PT object in the signal cone
    Iter leadingCand = leadCand(
        getCollection(kSignal, kAll)->begin(),
        getCollection(kSignal, kAll)->end());

    if ( leadingCand != getCollection(kSignal, kAll)->end() )
      tau_->setleadCand(*leadingCand);

    // Hardest charged object in signal cone
    Iter leadingChargedCand = leadCand(
        getCollection(kSignal, kChargedHadron)->begin(),
        getCollection(kSignal, kChargedHadron)->end());

    if ( leadingChargedCand != getCollection(kSignal, kChargedHadron)->end() )
      tau_->setleadChargedHadrCand(*leadingChargedCand);

    // Hardest gamma object in signal cone
    Iter leadingGammaCand = leadCand(
        getCollection(kSignal, kGamma)->begin(),
        getCollection(kSignal, kGamma)->end());

    if(leadingGammaCand != getCollection(kSignal, kGamma)->end())
      tau_->setleadNeutralCand(*leadingGammaCand);
  }
  return tau_;
}
} // end namespace reco::tau