GenHFHadronMatcher.cc

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// -*- C++ -*-
//
// Package:    GenHFHadronMatcher
// Class:      GenHFHadronMatcher
//

// Original Author:  Nazar Bartosik,DESY


// system include files
#include <memory>
#include <utility>
#include <vector>
#include <algorithm>


// user include files
#include "FWCore/Framework/interface/Frameworkfwd.h"
#include "FWCore/Framework/interface/global/EDProducer.h"

#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Framework/interface/MakerMacros.h"

#include "FWCore/ParameterSet/interface/ParameterSet.h"

#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include "FWCore/Framework/interface/ESHandle.h"
#include "FWCore/Framework/interface/EventSetup.h"
#include "FWCore/Utilities/interface/EDPutToken.h"

#include "DataFormats/HepMCCandidate/interface/GenParticle.h"

#include "DataFormats/JetReco/interface/GenJet.h"
#include "DataFormats/JetReco/interface/Jet.h"
#include "DataFormats/Math/interface/deltaR.h"

#include "SimDataFormats/JetMatching/interface/JetFlavourInfoMatching.h"


//
// class declaration
//

class GenHFHadronMatcher : public edm::global::EDProducer<>
{
public:
    explicit GenHFHadronMatcher ( const edm::ParameterSet& );
    ~GenHFHadronMatcher() override;

    static void fillDescriptions ( edm::ConfigurationDescriptions& descriptions );

private:
    void produce( edm::StreamID, edm::Event&, const edm::EventSetup& ) const override;

    std::vector<int> findHadronJets( const reco::GenParticleCollection* genParticles, const reco::JetFlavourInfoMatchingCollection* jetFlavourInfos,
                                     std::vector<int> &hadIndex, std::vector<reco::GenParticle> &hadMothersGenPart, 
                                     std::vector<std::vector<int> > &hadMothersIndices, std::vector<int> &hadLeptonIndex, 
                                     std::vector<int> &hadLeptonHadIndex, std::vector<int> &hadLeptonViaTau, 
                                     std::vector<int> &hadFlavour, std::vector<int> &hadFromTopWeakDecay, std::vector<int> &hadBHadronId ) const;
    int analyzeMothers( const reco::Candidate* thisParticle, int& topDaughterQId, int& topBarDaughterQId, 
                        std::vector<const reco::Candidate*> &hadMothers, std::vector<std::vector<int> > &hadMothersIndices, 
                        std::set<const reco::Candidate*> *analyzedParticles, const int prevPartIndex ) const;
    bool putMotherIndex( std::vector<std::vector<int> > &hadMothersIndices, int partIndex, int mothIndex ) const;
    bool isHadron( const int flavour, const reco::Candidate* thisParticle ) const;
    bool isHadronPdgId( const int flavour, const int pdgId ) const;
    bool isMesonPdgId( const int flavour, const int pdgId ) const;
    bool isBaryonPdgId( const int flavour, const int pdgId ) const;
    int flavourSign( const int pdgId ) const;
    bool hasHadronDaughter( const int flavour, const reco::Candidate* thisParticle ) const;
    int idInList( std::vector<const reco::Candidate*> particleList, const reco::Candidate* particle ) const;
    int idInList( std::vector<int> list, const int value ) const;
    int findInMothers( int idx, std::vector<int> &mothChains, const std::vector<std::vector<int> > &hadMothersIndices,
                       const std::vector<reco::GenParticle> &hadMothers, int status, int pdgId, bool pdgAbs,
                       int stopId, int firstLast, bool verbose ) const;
    bool isNeutralPdg( int pdgId ) const;

    bool checkForLoop( std::vector<const reco::Candidate*> &particleChain, const reco::Candidate* particle ) const;
    std::string getParticleName( int id ) const;

    bool fixExtraSameFlavours( const unsigned int hadId, const std::vector<int> &hadIndices, 
                               const std::vector<reco::GenParticle> &hadMothers, const std::vector<std::vector<int> > &hadMothersIndices, 
                               const std::vector<int> &isFromTopWeakDecay, const std::vector<std::vector<int> > &LastQuarkIds, 
                               const std::vector<std::vector<int> > &LastQuarkMotherIds, std::vector<int> &lastQuarkIndices, 
                               std::vector<int> &hadronFlavour, std::set<int> &checkedHadronIds, const int lastQuarkIndex ) const;

    // ----------member data ---------------------------
    const edm::EDGetTokenT<reco::GenParticleCollection> genParticlesToken_;
    const edm::EDGetTokenT<reco::JetFlavourInfoMatchingCollection> jetFlavourInfosToken_;
    const int flavour_;
    const bool noBBbarResonances_;
    const bool onlyJetClusteredHadrons_;

    const std::string flavourStr_;
    const edm::EDPutTokenT< std::vector<reco::GenParticle> > plusMothersToken_;
    const edm::EDPutTokenT< std::vector< std::vector<int> > > plusMothersIndicesToken_;
    const edm::EDPutTokenT< std::vector<int> > indexToken_;
    const edm::EDPutTokenT< std::vector<int> > flavourToken_;
    const edm::EDPutTokenT< std::vector<int> > jetIndexToken_;
    const edm::EDPutTokenT< std::vector<int> > leptonIndexToken_;
    const edm::EDPutTokenT< std::vector<int> > leptonHadronIndexToken_;
    const edm::EDPutTokenT< std::vector<int> > leptonViaTauToken_;
    const edm::EDPutTokenT< std::vector<int> > fromTopWeakDecayToken_;
    const edm::EDPutTokenT< std::vector<int> > bHadronIdToken_;


};

//
// constants, enums and typedefs
//


//
// static data member definitions
//

//
// constructors and destructor
//
namespace {
  std::string flavourName(int flavour) {
    if ( flavour==5 ) {
        return "B";
    } else if ( flavour==4 ) {
        return "C";
    }
    edm::LogError ( "GenHFHadronMatcher" ) << "Flavour option must be 4 (c-jet) or 5 (b-jet), but is: " << flavour << ". Correct this!";
    return std::string();
  }
}

GenHFHadronMatcher::GenHFHadronMatcher ( const edm::ParameterSet& cfg ):
genParticlesToken_(consumes<reco::GenParticleCollection>(cfg.getParameter<edm::InputTag>("genParticles"))),
jetFlavourInfosToken_(consumes<reco::JetFlavourInfoMatchingCollection>(cfg.getParameter<edm::InputTag>("jetFlavourInfos"))),
flavour_{std::abs(cfg.getParameter<int> ( "flavour" ))},
noBBbarResonances_{cfg.getParameter<bool> ( "noBBbarResonances" )},
onlyJetClusteredHadrons_{cfg.getParameter<bool> ( "onlyJetClusteredHadrons" )},
flavourStr_{flavourName(flavour_)},
plusMothersToken_{produces< std::vector<reco::GenParticle> > ( "gen"+flavourStr_+"HadPlusMothers" )}, // All mothers in all decay chains above any hadron of specified flavour
plusMothersIndicesToken_{produces< std::vector< std::vector<int> > > ( "gen"+flavourStr_+"HadPlusMothersIndices" )}, // Indices of mothers of each hadMother
indexToken_{produces< std::vector<int> > ( "gen"+flavourStr_+"HadIndex" )}, // Index of hadron in the vector of hadMothers
flavourToken_{produces< std::vector<int> > ( "gen"+flavourStr_+"HadFlavour" )}, // PdgId of the first non-b(c) quark mother with sign corresponding to hadron charge
jetIndexToken_{produces< std::vector<int> > ( "gen"+flavourStr_+"HadJetIndex" )}, // Index of genJet matched to each hadron by jet clustering algorithm
leptonIndexToken_{produces< std::vector<int> > ( "gen"+flavourStr_+"HadLeptonIndex" )}, // Index of lepton found among the hadron decay products in the list of mothers
leptonHadronIndexToken_{produces< std::vector<int> > ( "gen"+flavourStr_+"HadLeptonHadronIndex" )}, // Index of hadron the lepton is associated to
leptonViaTauToken_{produces< std::vector<int> > ( "gen"+flavourStr_+"HadLeptonViaTau" )}, // Whether lepton comes directly from hadron or via tau decay
fromTopWeakDecayToken_{produces< std::vector<int> > ( "gen"+flavourStr_+"HadFromTopWeakDecay" )}, // Tells whether the hadron appears in the chain after top decay
bHadronIdToken_{produces< std::vector<int> > ( "gen"+flavourStr_+"HadBHadronId" )} // Index of a b-hadron which the current hadron comes from (for c-hadrons)
{
    // Hadron matching products
}

GenHFHadronMatcher::~GenHFHadronMatcher()
{
}


// ------------ method fills 'descriptions' with the allowed parameters for the module  ------------
void GenHFHadronMatcher::fillDescriptions ( edm::ConfigurationDescriptions& descriptions )
{
    edm::ParameterSetDescription desc;
    desc.add<edm::InputTag>("genParticles")->setComment( "Collection of GenParticle objects which contains all particles produced in the event" );
    desc.add<edm::InputTag>("jetFlavourInfos")->setComment( "Output from the JetFlavour tool. Contains information about partons/hadrons/leptons associated to jets" );
    desc.add<bool> ( "noBBbarResonances",true )->setComment ( "Whether resonances should not be treated as hadrons" );
    desc.add<bool> ( "onlyJetClusteredHadrons",false )->setComment ( "Whether only hadrons that are matched to jets should be analysed. Runs x1000 faster in Sherpa" );
    desc.add<int> ( "flavour",5 )->setComment ( "Flavour of weakly decaying hadron that should be analysed (4-c, 5-b)" );
    descriptions.add ( "matchGenHFHadron",desc );
}



//
// member functions
//

// ------------ method called to produce the data  ------------
void GenHFHadronMatcher::produce ( edm::StreamID, edm::Event& evt, const edm::EventSetup& setup ) const
{
    using namespace edm;

    edm::Handle<reco::GenParticleCollection> genParticles;
    evt.getByToken(genParticlesToken_, genParticles);
    
    edm::Handle<reco::JetFlavourInfoMatchingCollection> jetFlavourInfos;
    evt.getByToken(jetFlavourInfosToken_, jetFlavourInfos);
    
    // Defining adron matching variables
    std::vector<reco::GenParticle> hadMothers;
    std::vector<std::vector<int>> hadMothersIndices;
    std::vector<int> hadIndex;
    std::vector<int> hadFlavour;
    std::vector<int> hadJetIndex;
    std::vector<int> hadLeptonIndex;
    std::vector<int> hadLeptonHadIndex;
    std::vector<int> hadLeptonViaTau;
    std::vector<int> hadFromTopWeakDecay;
    std::vector<int> hadBHadronId;
    
    hadJetIndex = findHadronJets (genParticles.product(), jetFlavourInfos.product(), hadIndex, hadMothers, hadMothersIndices, hadLeptonIndex, hadLeptonHadIndex, hadLeptonViaTau, hadFlavour, hadFromTopWeakDecay, hadBHadronId );

    // Putting products to the event
    evt.emplace(plusMothersToken_, std::move(hadMothers));
    evt.emplace(plusMothersIndicesToken_, std::move(hadMothersIndices));
    evt.emplace(indexToken_, std::move(hadIndex));
    evt.emplace(flavourToken_, std::move(hadFlavour));
    evt.emplace(jetIndexToken_, std::move(hadJetIndex));
    evt.emplace(leptonIndexToken_, std::move(hadLeptonIndex));
    evt.emplace(leptonHadronIndexToken_, std::move(hadLeptonHadIndex));
    evt.emplace(leptonViaTauToken_, std::move(hadLeptonViaTau));
    evt.emplace(fromTopWeakDecayToken_, std::move(hadFromTopWeakDecay));
    evt.emplace(bHadronIdToken_, std::move(hadBHadronId));
}


std::vector<int> GenHFHadronMatcher::findHadronJets ( const reco::GenParticleCollection* genParticles, 
                                                      const reco::JetFlavourInfoMatchingCollection* jetFlavourInfos,
                                                      std::vector<int> &hadIndex, 
                                                      std::vector<reco::GenParticle> &hadMothers, std::vector<std::vector<int> > &hadMothersIndices, 
                                                      std::vector<int> &hadLeptonIndex, std::vector<int> &hadLeptonHadIndex, 
                                                      std::vector<int> &hadLeptonViaTau, std::vector<int> &hadFlavour, 
                                                      std::vector<int> &hadFromTopWeakDecay, std::vector<int> &hadBHadronId ) const
{
    std::vector<int> hadJetIndex;
    std::vector<const reco::Candidate*> hadMothersCand;

    int topDaughterQId = -1;
    int topBarDaughterQId = -1;
    
    // Looping over all jets to get hadrons associated to them
    for(reco::JetFlavourInfoMatchingCollection::const_iterator i_info  = jetFlavourInfos->begin(); i_info != jetFlavourInfos->end(); ++i_info){
        reco::JetFlavourInfo jetInfo = i_info->second;
        const int jetIndex = i_info - jetFlavourInfos->begin();
        // Looping over each hadron associated with the jet and finding its origin
        const reco::GenParticleRefVector& hadronsInJet = flavour_==5 ? jetInfo.getbHadrons() : flavour_==4 ? jetInfo.getcHadrons() : reco::GenParticleRefVector();
        for(reco::GenParticleRefVector::const_iterator hadron = hadronsInJet.begin(); hadron != hadronsInJet.end(); ++hadron) {
            // Check that the hadron satisfies criteria configured in the module
            if(!isHadron ( flavour_, (&**hadron) )) continue;
            if(hasHadronDaughter ( flavour_, (reco::Candidate*)(&**hadron) )) continue;
            // Scanning the chain starting from the hadron
            int hadronIndex = analyzeMothers ( (reco::Candidate*)(&**hadron), topDaughterQId, topBarDaughterQId, hadMothersCand, hadMothersIndices, nullptr, -1 );
            // Storing the index of the hadron to the list
            hadIndex.push_back ( hadronIndex );
            hadJetIndex.push_back ( jetIndex );  // Putting jet index to the result list
        }
    }       // End of loop over jets
    
    // Access all hadrons which are not associated with jets, if requested
    if(!onlyJetClusteredHadrons_) {
        for(reco::GenParticleCollection::const_iterator i_particle = genParticles->begin(); i_particle != genParticles->end(); ++i_particle){
            const reco::GenParticle* thisParticle = &*i_particle;
            if(!isHadron(flavour_, thisParticle)) continue;
            // Skipping the hadron if it was already found directly from jets
            if(std::find(hadMothersCand.begin(), hadMothersCand.end(), thisParticle) != hadMothersCand.end()) continue;
            
            // Scanning the chain starting from the hadron
            int hadronIndex = analyzeMothers ( thisParticle, topDaughterQId, topBarDaughterQId, hadMothersCand, hadMothersIndices, nullptr, -1 );
            // Storing the index of the hadron to the list
            hadIndex.push_back ( hadronIndex );
            hadJetIndex.push_back ( -1 );  // Jet index undefined
        }
    }
    
    // Transfering Candidates to the list of processed particles for further analysis
    for ( int i=0; i< (int)hadMothersCand.size(); i++ ) {
        const reco::GenParticle* particle = dynamic_cast<const reco::GenParticle*>( hadMothersCand.at(i) );
        hadMothers.push_back(*particle);
    }
    
    // Adding leptons from hadron decays
    for(reco::GenParticleCollection::const_iterator i_particle = genParticles->begin(); i_particle != genParticles->end(); ++i_particle){
        const reco::GenParticle lepton = *i_particle;
        const int pdg_abs = lepton.pdgId();
        // Skipping if not a lepton: e/mu
        if(pdg_abs != 11 && pdg_abs != 13) continue;
        bool leptonViaTau = false;
        const reco::Candidate* leptonMother = lepton.mother();
        if(!leptonMother) continue;
        // Taking next mother if direct mother is a tau
        if(std::abs(leptonMother->pdgId()) == 15) {
            leptonViaTau = true;
            leptonMother = leptonMother->mother();
        }
        // Skipping this lepton if its mother is not a proper hadron
        if(leptonMother == nullptr or !isHadron(flavour_, leptonMother)) continue;
        // Finding the index of this hadron in the list of analysed particles
        size_t leptonHadronParticleIndex = std::find(hadMothersCand.begin(), hadMothersCand.end(), leptonMother) - hadMothersCand.begin();
        if(leptonHadronParticleIndex >= hadMothersCand.size()) continue;
        // Finding the actual hadron index among those that were found
        size_t leptonHadronIndex = std::find(hadIndex.begin(), hadIndex.end(), leptonHadronParticleIndex) - hadIndex.begin();
        if(leptonHadronIndex >= hadIndex.size()) continue;
        // Putting the lepton, its index and hadron index to the corresponding lists
        hadMothers.push_back(lepton);
        const int leptonIndex = hadMothersCand.size()-1;
        hadLeptonIndex.push_back(leptonIndex);
        hadLeptonViaTau.push_back(leptonViaTau);
        hadLeptonHadIndex.push_back(leptonHadronIndex);
    }

    // Checking mothers of hadrons in order to assign flags (where the hadron comes from)
    unsigned int nHad = hadIndex.size();

    std::vector<std::vector<int> > LastQuarkMotherIds;
    std::vector<std::vector<int> > LastQuarkIds;
    std::vector<int> lastQuarkIndices(nHad, -1);

    // Looping over all hadrons
    for ( unsigned int hadNum=0; hadNum<nHad; hadNum++ ) {
        unsigned int hadIdx = hadIndex.at(hadNum);   // Index of hadron in the hadMothers

        std::vector <int> FirstQuarkId;
        std::vector <int> LastQuarkId;
        std::vector <int> LastQuarkMotherId;

        const int hadronFlavourSign = flavourSign( hadMothers.at(hadIdx).pdgId() );

        // Searching only first quark in the chain with the same flavour as hadron
        if(hadronFlavourSign != 0) {
            findInMothers( hadIdx, FirstQuarkId, hadMothersIndices, hadMothers, 0, hadronFlavourSign*flavour_, false, -1, 1, false );
        }
        // Searching for quarks with both flavours since it is a bb/cc resonance
        else {
            findInMothers( hadIdx, FirstQuarkId, hadMothersIndices, hadMothers, 0, flavour_, false, -1, 1, false );
            findInMothers( hadIdx, FirstQuarkId, hadMothersIndices, hadMothers, 0, -1*flavour_, false, -1, 1, false );
        }

        // Finding last quark for each first quark
        for ( unsigned int qId=0; qId<FirstQuarkId.size(); qId++ ) {
            // Identifying the flavour of the first quark to find the last quark of the same flavour
            const int quarkFlavourSign = flavourSign( hadMothers.at(FirstQuarkId.at(qId)).pdgId() );
            // Finding last quark of the hadron starting from the first quark
            findInMothers( FirstQuarkId.at(qId), LastQuarkId, hadMothersIndices, hadMothers, 0, quarkFlavourSign*flavour_, false, -1, 2, false );
        }       // End of loop over all first quarks of the hadron


        // Setting initial flavour of the hadron
        int hadronFlavour = 0;

        // Initialising pairs of last quark index and its distance from the hadron (to sort by distance)
        std::vector<std::pair<double, int> > lastQuark_dR_id_pairs;

        // Finding the closest quark in dR
        for ( unsigned int qId = 0; qId < LastQuarkId.size(); qId++ ) {
            int qIdx = LastQuarkId.at(qId);
            // Calculating the dR between hadron and quark
            float dR = deltaR ( hadMothers.at(hadIdx).eta(),hadMothers.at(hadIdx).phi(),hadMothers.at(qIdx).eta(),hadMothers.at(qIdx).phi() );

            std::pair<double, int> dR_hadId_pair(dR,qIdx);
            lastQuark_dR_id_pairs.push_back(dR_hadId_pair);
        }       // End of loop over all last quarks of the hadron

        std::sort(lastQuark_dR_id_pairs.begin(), lastQuark_dR_id_pairs.end());
        
        if(lastQuark_dR_id_pairs.size() > 1) {
            double dRratio = (lastQuark_dR_id_pairs.at(1).first - lastQuark_dR_id_pairs.at(0).first)/lastQuark_dR_id_pairs.at(1).first;
            int qIdx_closest = lastQuark_dR_id_pairs.at(0).second;
            LastQuarkId.clear();
            if(dRratio>0.5) LastQuarkId.push_back(qIdx_closest); 
            else for(std::pair<double, int> qIdDrPair : lastQuark_dR_id_pairs) LastQuarkId.push_back(qIdDrPair.second);
        }
        for(int qIdx : LastQuarkId) {
            int qmIdx = hadMothersIndices.at(qIdx).at(0);
            LastQuarkMotherId.push_back(qmIdx);
        }

        if((int)LastQuarkId.size()>0) lastQuarkIndices.at(hadNum) = 0;     // Setting the first quark in array as a candidate if it exists

        LastQuarkIds.push_back( LastQuarkId );

        LastQuarkMotherIds.push_back ( LastQuarkMotherId );

        if(LastQuarkMotherId.empty()) {
            hadronFlavour = 0;
        } else {
            int qIdx = LastQuarkId.at( lastQuarkIndices.at(hadNum) );
            int qFlav = flavourSign( hadMothers.at(qIdx).pdgId() );
            hadronFlavour = qFlav*std::abs( hadMothers.at( LastQuarkMotherId.at( lastQuarkIndices.at(hadNum) ) ).pdgId() );
        }
        hadFlavour.push_back(hadronFlavour);    // Adding hadron flavour to the list of flavours
        
        // Checking whether hadron comes from the Top weak decay
        int isFromTopWeakDecay = 1;
        std::vector <int> checkedParticles;
        if(hadFlavour.at(hadNum) != 0) {
            int lastQIndex = LastQuarkId.at(lastQuarkIndices.at(hadNum));
            bool fromTB = topDaughterQId >= 0 ? findInMothers( lastQIndex, checkedParticles, hadMothersIndices, hadMothers, -1, 0, false, topDaughterQId, 2, false ) >= 0 : false;
            checkedParticles.clear();
            bool fromTbarB = topBarDaughterQId >= 0 ? findInMothers( lastQIndex, checkedParticles, hadMothersIndices, hadMothers, -1, 0, false, topBarDaughterQId, 2, false) >= 0 : false;
            checkedParticles.clear();
            if(!fromTB && !fromTbarB) {
                isFromTopWeakDecay = 0;
            }
        } else isFromTopWeakDecay = 2;
        hadFromTopWeakDecay.push_back(isFromTopWeakDecay);
        int bHadronMotherId = findInMothers( hadIdx, checkedParticles, hadMothersIndices, hadMothers, 0, 555555, true, -1, 1, false );
        hadBHadronId.push_back(bHadronMotherId);
        

        if(!LastQuarkMotherId.empty()) {
            std::set<int> checkedHadronIds;
            fixExtraSameFlavours(hadNum, hadIndex, hadMothers, hadMothersIndices, hadFromTopWeakDecay, LastQuarkIds, LastQuarkMotherIds, lastQuarkIndices, hadFlavour, checkedHadronIds, 0);
        }
        
    }   // End of loop over all hadrons

    return hadJetIndex;
}


int GenHFHadronMatcher::idInList ( std::vector<const reco::Candidate*> particleList, const reco::Candidate* particle ) const
{
    const unsigned int position = std::find(particleList.begin(), particleList.end(), particle) - particleList.begin();
    if( position >= particleList.size() ) return -1;
    
    return position;
}

int GenHFHadronMatcher::idInList ( std::vector<int> list, const int value ) const
{
    const unsigned int position = std::find(list.begin(), list.end(), value) - list.begin();
    if( position >= list.size() ) return -1;
    
    return position;
}


bool GenHFHadronMatcher::isHadron ( const int flavour, const reco::Candidate* thisParticle ) const
{
    return isHadronPdgId(flavour, thisParticle->pdgId());
}


bool GenHFHadronMatcher::isHadronPdgId ( const int flavour, const int pdgId ) const
{
    if( isBaryonPdgId(flavour, pdgId) || isMesonPdgId(flavour, pdgId) ) return true;
    
    return false;
}


bool GenHFHadronMatcher::isMesonPdgId ( const int flavour, const int pdgId ) const
{
    const int flavour_abs = std::abs(flavour);
    if(flavour_abs != 5 && flavour_abs != 4) return false;
    const int pdgId_abs = std::abs(pdgId);

    if( pdgId_abs/100%10 != flavour_abs) return false;
    // Excluding baryons
    if ( pdgId_abs/1000 == flavour_abs) return false;
    // Excluding bb/cc resonances if required
    if ( noBBbarResonances_ && pdgId_abs/10%100 == 11*flavour_abs ) return false;
    
    return true;
}


bool GenHFHadronMatcher::isBaryonPdgId ( const int flavour, const int pdgId ) const
{
    const int flavour_abs = std::abs(flavour);
    if(flavour_abs != 5 && flavour_abs != 4) return false;
    const int pdgId_abs = std::abs(pdgId);

    if ( pdgId_abs/1000 != flavour_abs) return false;
    
    return true;
}


int GenHFHadronMatcher::flavourSign ( const int pdgId ) const
{
    int flavourSign = pdgId / std::abs(pdgId);
    // B mesons have opposite sign
    if( isMesonPdgId(5, pdgId) ) flavourSign *= -1;
    // Returning 0 for bb/cc resonances
    if(pdgId % 1000 / 10 / 11 > 0) flavourSign = 0;
    
    return flavourSign;
}


bool GenHFHadronMatcher::hasHadronDaughter ( const int flavour, const reco::Candidate* thisParticle ) const
{
    // Looping through daughters of the particle
    bool hasDaughter = false;
    for ( int k=0; k< (int)thisParticle->numberOfDaughters(); k++ ) {
        if ( !isHadron( flavour, thisParticle->daughter(k) ) ) {
            continue;
        }
        hasDaughter = true;
        break;
    }
    
    return hasDaughter;
}


int GenHFHadronMatcher::analyzeMothers ( const reco::Candidate* thisParticle, int& topDaughterQId, int& topBarDaughterQId, std::vector<const reco::Candidate*> &hadMothers, std::vector<std::vector<int> > &hadMothersIndices, std::set<const reco::Candidate*> *analyzedParticles, const int prevPartIndex ) const
{
    // Getting the index of the particle which is a hadron in the first call
    int hadronIndex=-1; // Index of the hadron that is returned by this function
    int index = idInList( hadMothers, thisParticle );
    if ( index<0 ) { // If hadron is not in the list of mothers yet
        hadMothers.push_back ( thisParticle );
        hadronIndex=hadMothers.size()-1;
    } else {        // If hadron is in the list of mothers already
        hadronIndex=index;
    }
    
    int partIndex = -1;   // Index of particle being checked in the list of mothers
    partIndex = idInList( hadMothers, thisParticle );

    // Checking whether this particle is already in the chain of analyzed particles in order to identify a loop
    bool isLoop = false;
    if ( !analyzedParticles ) {
        analyzedParticles = new std::set<const reco::Candidate*>;
    }
    for ( unsigned int i=0; i<analyzedParticles->size(); i++ ) {
        if ( analyzedParticles->count ( thisParticle ) <=0 ) {
            continue;
        }
        isLoop = true;
        break;
    }
    
    // If a loop has been detected
    if ( isLoop ) {
        if ( prevPartIndex>=0 ) {
            putMotherIndex ( hadMothersIndices, prevPartIndex, -1 );    // Setting mother index of previous particle to -1
        }
        return hadronIndex;     // Stopping further processing of the current chain
    }
    analyzedParticles->insert ( thisParticle );
    
    // Putting the mothers to the list of mothers
    for ( size_t iMother = 0; iMother < thisParticle->numberOfMothers(); ++iMother ) {
        const reco::Candidate* mother = thisParticle->mother ( iMother );
        int mothIndex = idInList( hadMothers, mother );
        if ( mothIndex == partIndex && partIndex>=0 ) {
            continue;       // Skipping the mother that is its own daughter
        }

    // If this mother isn't yet in the list and hadron or lepton is in the list
        if ( mothIndex<0 ) {
            hadMothers.push_back ( mother );
            mothIndex=hadMothers.size()-1;
        }
    // If hadron has already been found in current chain and the mother isn't a duplicate of the particle being checked
        if ( mothIndex!=partIndex && partIndex>=0 ) {
            putMotherIndex ( hadMothersIndices, partIndex, mothIndex );         // Putting the index of mother for current particle
        }
        analyzeMothers ( mother, topDaughterQId, topBarDaughterQId, hadMothers, hadMothersIndices, analyzedParticles, partIndex );
        // Setting the id of the particle which is a quark from the top decay
        if(std::abs(mother->pdgId())==6) {
            int& bId = mother->pdgId() < 0 ? topBarDaughterQId : topDaughterQId;
            int thisFlav = std::abs(thisParticle->pdgId());
            if( bId<0){
                if(thisFlav <= 5) bId = partIndex; 
            } else {
                int bIdFlav = std::abs(hadMothers.at(bId)->pdgId());
                if( bIdFlav != 5 && thisFlav == 5) bId = partIndex;
                else if( thisFlav == 5 && thisParticle->pt() > hadMothers.at(bId)->pt() ) bId = partIndex;
            }           // If daughter quark of the top not found yet
        }           // If the mother is a top quark and hadron has been found
    }         // End of loop over mothers

    analyzedParticles->erase ( thisParticle );      // Removing current particle from the current chain that is being analyzed

    if ( partIndex<0 ) {
        return hadronIndex;    // Safety check
    }

    // Adding -1 to the list of mother indices for current particle if it has no mothers (for consistency between numbering of indices and mothers)
    if ( (int)thisParticle->numberOfMothers() <=0) {
        putMotherIndex ( hadMothersIndices, partIndex, -1 );
    }

    return hadronIndex;

}


bool GenHFHadronMatcher::putMotherIndex ( std::vector<std::vector<int> > &hadMothersIndices, int partIndex, int mothIndex ) const
{
    // Putting vector of mothers indices for the given particle
    bool inList=false;
    if ( partIndex<0 ) {
        return false;
    }

    while ( (int)hadMothersIndices.size() <= partIndex ) { // If there is no list of mothers for current particle yet
        std::vector<int> mothersIndices;
        hadMothersIndices.push_back ( mothersIndices );
    }

    std::vector<int> *hadMotherIndices = &hadMothersIndices.at(partIndex);
    // Removing other mothers if particle must have no mothers
    if ( mothIndex == -1 ) {
        hadMotherIndices->clear();
    } else {
        // Checking if current mother is already in the list of theParticle's mothers
        for ( int k = 0; k < (int)hadMotherIndices->size(); k++ ) {
            if ( hadMotherIndices->at(k) != mothIndex && hadMotherIndices->at(k) != -1 ) {
                continue;
            }
            inList=true;
            break;
        }
    }
    // Adding current mother to the list of mothers of this particle
    if ( !inList ) {
        hadMotherIndices->push_back(mothIndex);
    }

    return inList;
}


int GenHFHadronMatcher::findInMothers ( int idx, std::vector<int> &mothChains, const std::vector<std::vector<int> > &hadMothersIndices,
                                        const std::vector<reco::GenParticle> &hadMothers, int status, int pdgId, bool pdgAbs=false, 
                                        int stopId=-1, int firstLast=0, bool verbose=false) const
{
    int foundStopId = -1;
    int pdg_1 = hadMothers.at(idx).pdgId();

    if ( (int)hadMothersIndices.size() <= idx ) {
        if ( verbose ) {
            printf ( " Stopping checking particle %d. No mothers are stored.\n",idx );
        }
        return -1;     // Skipping if no mothers are stored for this particle
    }
    
    if(std::abs(hadMothers.at( idx ).pdgId()) > 10 &&  std::abs(hadMothers.at( idx ).pdgId()) < 19) printf("Lepton: %d\n", hadMothers.at( idx ).pdgId());

    std::vector<int> mothers = hadMothersIndices.at(idx);
    unsigned int nMothers = mothers.size();
    bool isCorrect=false;       // Whether current particle is what is being searched
    if ( verbose ) {
        if ( std::abs( hadMothers.at(idx).pdgId() ) ==2212 ) {
            printf ( "Chk:  %d\tpdg: %d\tstatus: %d",idx, hadMothers.at(idx).pdgId(), hadMothers.at(idx).status() );
        } else {
            printf ( " Chk:  %d(%d mothers)\tpdg: %d\tstatus: %d\tPt: %.3f\tEta: %.3f",idx, nMothers, hadMothers.at(idx).pdgId(), hadMothers.at(idx).status(), hadMothers.at(idx).pt(),hadMothers.at(idx).eta() );
        }
    }
    bool hasCorrectMothers = true;
    if(nMothers<1) hasCorrectMothers=false; else if(mothers.at(0)<0) hasCorrectMothers=false;
    if(!hasCorrectMothers) {
        if(verbose) printf("    NO CORRECT MOTHER\n");
        return -1;
    }
    // Stopping if the particular particle has been found
    if(stopId>=0 && idx == stopId) return idx;
    
    // Stopping if the hadron of particular flavour has been found
    if(pdgId%111111==0 && pdgId!=0) {
        if(isHadronPdgId(pdgId/111111, hadMothers.at(idx).pdgId())) {
            return idx;
        }
    }
    
    // Checking whether current mother satisfies selection criteria
    if ( ( ( hadMothers.at(idx).pdgId() == pdgId && pdgAbs==false )
            || ( std::abs( hadMothers.at(idx).pdgId() ) == std::abs( pdgId ) && pdgAbs==true ) )
            && ( hadMothers.at(idx).status() == status || status==0 )
            && hasCorrectMothers ) {
        isCorrect=true;
        // Adding to the list of candidates if not there and if mother of this quark has correct flavour sign
        const bool inList = std::find(mothChains.begin(), mothChains.end(), idx) != mothChains.end();
        if ( !inList && mothers.at(0) >= 0 && ( hadMothers.at(idx).pdgId()*pdgId > 0 || !pdgAbs ) ) {
            if ( firstLast==0 || firstLast==1 ) {
                mothChains.push_back(idx);
            }
            if ( verbose ) {
                printf ( "   *" );
            }
        }
        if ( verbose ) {
            printf ( "   +++" );
        }
    }
    if ( verbose ) {
        printf ( "\n" );
    }

    if ( isCorrect && firstLast==1 ) {
        return -1;   // Stopping if only the first particle in the chain is looked for
    }
    
    // Checking next level mothers
    unsigned int nDifferingMothers = 0;
    for ( unsigned int i = 0; i < nMothers; i++ ) {
        int idx2 = mothers.at(i);
        if ( idx2 < 0 ) {
        if(verbose) printf("^^^ Has no mother\n");
            continue;    // Skipping if mother's id is -1 (no mother), that means current particle is a proton
        }
        if ( idx2 == idx ) {
        if(verbose) printf("^^^ Stored as its own mother\n");
            continue;    // Skipping if particle is stored as its own mother
        }
        int pdg_2 = hadMothers[idx2].pdgId();
        // Inverting the flavour if bb oscillation detected
        if ( isHadronPdgId(pdgId, pdg_1) && isHadronPdgId(pdgId, pdg_2) &&  pdg_1*pdg_2 < 0 ) {
            pdgId *= -1;
            if(verbose) printf("######### Inverting flavour of the hadron\n");
        }
    // Counting how many mothers are different from this particle
        if ( ( std::abs( pdg_2 ) != std::abs( pdgId ) && pdgAbs==true ) ||
             ( pdg_2 != pdgId && pdgAbs == false ) ) {
        nDifferingMothers++;
        }

        // Checking next level mother
        if ( verbose ) {
            printf ( "Checking mother %d out of %d mothers (%d -> %d), looking for pdgId: %d\n",i,nMothers,idx, idx2, pdgId );
        }
        if(firstLast==2 && pdg_1 != pdg_2) continue;    // Requiring the same flavour when finding the last quark
        foundStopId = findInMothers ( idx2, mothChains, hadMothersIndices, hadMothers, status, pdgId, pdgAbs, stopId, firstLast, verbose );
    }
    // Storing this particle if all its mothers are of another type and the last of its kind should be stored
    if(firstLast==2 && isCorrect && nDifferingMothers >= nMothers) {
        if ( verbose ) {
            printf ( "Checking particle %d once more to store it as the last quark\n",idx);
        }
        foundStopId = findInMothers ( idx, mothChains, hadMothersIndices, hadMothers, 0, pdgId, pdgAbs, stopId, 1, verbose );
    }
    
    return foundStopId;
}


bool GenHFHadronMatcher::isNeutralPdg ( int pdgId ) const
{
    const int neutralPdgs_array[] = {9, 21, 22, 23, 25};
    const std::vector<int> neutralPdgs( neutralPdgs_array, neutralPdgs_array + sizeof(neutralPdgs_array) / sizeof(int) );
    if( std::find( neutralPdgs.begin(), neutralPdgs.end(), std::abs(pdgId) ) == neutralPdgs.end() ) return false;
    
    return true;
}


bool GenHFHadronMatcher::fixExtraSameFlavours(
    const unsigned int hadId, const std::vector<int> &hadIndices, const std::vector<reco::GenParticle> &hadMothers, 
    const std::vector<std::vector<int> > &hadMothersIndices, const std::vector<int> &isFromTopWeakDecay, 
    const std::vector<std::vector<int> > &LastQuarkIds, const std::vector<std::vector<int> > &LastQuarkMotherIds, 
    std::vector<int> &lastQuarkIndices, std::vector<int> &hadronFlavour, 
    std::set<int> &checkedHadronIds, const int lastQuarkIndex) const
{
    if(checkedHadronIds.count(hadId) != 0) return false;      // Hadron already checked previously and should be skipped
    checkedHadronIds.insert(hadId);                           // Putting hadron to the list of checked ones in this run

    if(lastQuarkIndex<0) return false;
    if((int)LastQuarkIds.at(hadId).size()<lastQuarkIndex+1) return false;
    int LastQuarkId = LastQuarkIds.at(hadId).at(lastQuarkIndex);
    int LastQuarkMotherId = LastQuarkMotherIds.at( hadId ).at( lastQuarkIndex );
    int qmFlav = hadMothers.at(LastQuarkId).pdgId() < 0 ? -1 : 1;
    int hadFlavour = qmFlav*std::abs( hadMothers.at( LastQuarkMotherId ).pdgId() );
    bool ambiguityResolved = true;
    // If last quark has inconsistent flavour with its mother, setting the hadron flavour to gluon
    if( (hadMothers.at(LastQuarkId).pdgId()*hadMothers.at(LastQuarkMotherId).pdgId() < 0 && !isNeutralPdg(hadMothers.at(LastQuarkMotherId).pdgId())) || 
        // If particle not coming from the Top weak decay has Top flavour
        (std::abs(hadronFlavour.at(hadId))==6 && isFromTopWeakDecay.at(hadId)==0) ) {
        if((int)LastQuarkIds.at(hadId).size()>lastQuarkIndex+1) fixExtraSameFlavours(hadId, hadIndices, hadMothers, hadMothersIndices, isFromTopWeakDecay, LastQuarkIds, LastQuarkMotherIds, lastQuarkIndices, hadronFlavour, checkedHadronIds, lastQuarkIndex+1); 
        else hadronFlavour.at(hadId) = qmFlav*21;
        return true;
    }

    int nSameFlavourHadrons = 0;
    // Looping over all previous hadrons
    for(unsigned int iHad = 0; iHad<hadronFlavour.size(); iHad++) {
        if(iHad==hadId) continue;
        int theLastQuarkIndex = lastQuarkIndices.at(iHad);
        if(theLastQuarkIndex<0) continue;
        if((int)LastQuarkMotherIds.at( iHad ).size() <= theLastQuarkIndex) continue;
        int theLastQuarkMotherId = LastQuarkMotherIds.at( iHad ).at( theLastQuarkIndex );
        int theHadFlavour = hadronFlavour.at(iHad);
        // Skipping hadrons with different flavour
        if(theHadFlavour==0 || std::abs(theHadFlavour)==21) continue;
        if(theHadFlavour != hadFlavour || theLastQuarkMotherId != LastQuarkMotherId) continue;
        ambiguityResolved = false;
        nSameFlavourHadrons++;
        
        // Checking other b-quark mother candidates of this hadron
        if((int)LastQuarkIds.at(hadId).size() > lastQuarkIndex+1) {
            if(fixExtraSameFlavours(hadId, hadIndices, hadMothers, hadMothersIndices, isFromTopWeakDecay, LastQuarkIds, LastQuarkMotherIds, lastQuarkIndices, hadronFlavour, checkedHadronIds, lastQuarkIndex+1) ) {
                ambiguityResolved = true;
                break;
            }
        } else
        // Checking other b-quark mother candidates of the particular previous hadron
        if((int)LastQuarkIds.at(iHad).size() > theLastQuarkIndex+1) {
            if(fixExtraSameFlavours(iHad, hadIndices, hadMothers, hadMothersIndices, isFromTopWeakDecay, LastQuarkIds, LastQuarkMotherIds, lastQuarkIndices, hadronFlavour, checkedHadronIds, theLastQuarkIndex+1) ) {
                ambiguityResolved = true;
                break;
            };
        } 

    }       // End of loop over all previous hadrons

    checkedHadronIds.erase(hadId);      // Removing the hadron from the list of checked hadrons
    if(nSameFlavourHadrons>0 && !ambiguityResolved) {
        hadronFlavour.at(hadId) = qmFlav*21;
        return true;
    }
    lastQuarkIndices.at(hadId) = lastQuarkIndex;
    hadronFlavour.at(hadId) = hadFlavour;
    return true;
}

//define this as a plug-in
DEFINE_FWK_MODULE ( GenHFHadronMatcher );