BoostedTopProducer Class Reference

#include <BoostedTopProducer.cc>

Inheritance diagram for BoostedTopProducer:

Public Member Functions
	BoostedTopProducer (const edm::ParameterSet &)
	~BoostedTopProducer () override
Public Member Functions inherited from edm::EDProducer
	EDProducer ()
SerialTaskQueue *	globalLuminosityBlocksQueue ()
SerialTaskQueue *	globalRunsQueue ()
ModuleDescription const &	moduleDescription () const
	~EDProducer () override
Public Member Functions inherited from edm::ProducerBase
void	callWhenNewProductsRegistered (std::function< void(BranchDescription const &)> const &func)
std::vector< edm::ProductResolverIndex > const &	indiciesForPutProducts (BranchType iBranchType) const
	ProducerBase ()
std::vector< edm::ProductResolverIndex > const &	putTokenIndexToProductResolverIndex () const
std::vector< bool > const &	recordProvenanceList () const
void	registerProducts (ProducerBase *, ProductRegistry *, ModuleDescription const &)
std::function< void(BranchDescription const &)>	registrationCallback () const
	used by the fwk to register list of products More...
void	resolvePutIndicies (BranchType iBranchType, ModuleToResolverIndicies const &iIndicies, std::string const &moduleLabel)
TypeLabelList const &	typeLabelList () const
	used by the fwk to register the list of products of this module More...
	~ProducerBase () noexcept(false) override
Public Member Functions inherited from edm::EDConsumerBase
std::vector< ConsumesInfo >	consumesInfo () const
void	convertCurrentProcessAlias (std::string const &processName)
	Convert "@currentProcess" in InputTag process names to the actual current process name. More...
	EDConsumerBase ()
	EDConsumerBase (EDConsumerBase &&)=default
	EDConsumerBase (EDConsumerBase const &)=delete
ESProxyIndex const *	esGetTokenIndices (edm::Transition iTrans) const
ProductResolverIndexAndSkipBit	indexFrom (EDGetToken, BranchType, TypeID const &) const
void	itemsMayGet (BranchType, std::vector< ProductResolverIndexAndSkipBit > &) const
void	itemsToGet (BranchType, std::vector< ProductResolverIndexAndSkipBit > &) const
std::vector< ProductResolverIndexAndSkipBit > const &	itemsToGetFrom (BranchType iType) const
void	labelsForToken (EDGetToken iToken, Labels &oLabels) const
void	modulesWhoseProductsAreConsumed (std::vector< ModuleDescription const * > &modules, ProductRegistry const &preg, std::map< std::string, ModuleDescription const * > const &labelsToDesc, std::string const &processName) const
EDConsumerBase &	operator= (EDConsumerBase &&)=default
EDConsumerBase const &	operator= (EDConsumerBase const &)=delete
bool	registeredToConsume (ProductResolverIndex, bool, BranchType) const
bool	registeredToConsumeMany (TypeID const &, BranchType) const
ProductResolverIndexAndSkipBit	uncheckedIndexFrom (EDGetToken) const
void	updateLookup (BranchType iBranchType, ProductResolverIndexHelper const &, bool iPrefetchMayGet)
void	updateLookup (eventsetup::ESRecordsToProxyIndices const &)
virtual	~EDConsumerBase () noexcept(false)

Private Member Functions
void	produce (edm::Event &, const edm::EventSetup &) override
double	Psi (const TLorentzVector &p1, const TLorentzVector &p2, double mass)

Private Attributes
double	caloIsoCut_
edm::EDGetTokenT< std::vector< pat::Electron > >	eleToken_
edm::EDGetTokenT< std::vector< pat::Jet > >	jetToken_
edm::EDGetTokenT< std::vector< pat::MET > >	metToken_
double	mTop_
edm::EDGetTokenT< std::vector< pat::Muon > >	muoToken_
edm::EDGetTokenT< TtSemiLeptonicEvent >	solToken_

Additional Inherited Members
Public Types inherited from edm::EDProducer
typedef EDProducer	ModuleType
Public Types inherited from edm::ProducerBase
using	ModuleToResolverIndicies = std::unordered_multimap< std::string, std::tuple< edm::TypeID const *, const char *, edm::ProductResolverIndex > >
typedef ProductRegistryHelper::TypeLabelList	TypeLabelList
Public Types inherited from edm::EDConsumerBase
typedef ProductLabels	Labels
Static Public Member Functions inherited from edm::EDProducer
static const std::string &	baseType ()
static void	fillDescriptions (ConfigurationDescriptions &descriptions)
static void	prevalidate (ConfigurationDescriptions &descriptions)
static bool	wantsGlobalLuminosityBlocks ()
static bool	wantsGlobalRuns ()
static bool	wantsStreamLuminosityBlocks ()
static bool	wantsStreamRuns ()
Protected Member Functions inherited from edm::ProducerBase
template<class ProductType >
BranchAliasSetterT< ProductType >	produces ()
	declare what type of product will make and with which optional label More...
template<typename ProductType , BranchType B>
BranchAliasSetterT< ProductType >	produces ()
template<typename ProductType , Transition B>
BranchAliasSetterT< ProductType >	produces ()
BranchAliasSetter	produces (const TypeID &id, std::string instanceName=std::string(), bool recordProvenance=true)
template<BranchType B>
BranchAliasSetter	produces (const TypeID &id, std::string instanceName=std::string(), bool recordProvenance=true)
template<Transition B>
BranchAliasSetter	produces (const TypeID &id, std::string instanceName=std::string(), bool recordProvenance=true)
template<typename ProductType , Transition B>
BranchAliasSetterT< ProductType >	produces (std::string instanceName)
template<class ProductType >
BranchAliasSetterT< ProductType >	produces (std::string instanceName)
template<typename ProductType , BranchType B>
BranchAliasSetterT< ProductType >	produces (std::string instanceName)
ProducesCollector	producesCollector ()
Protected Member Functions inherited from edm::EDConsumerBase
EDGetToken	consumes (const TypeToGet &id, edm::InputTag const &tag)
template<typename ProductType , BranchType B = InEvent>
EDGetTokenT< ProductType >	consumes (edm::InputTag const &tag)
template<BranchType B>
EDGetToken	consumes (TypeToGet const &id, edm::InputTag const &tag)
ConsumesCollector	consumesCollector ()
	Use a ConsumesCollector to gather consumes information from helper functions. More...
template<typename ProductType , BranchType B = InEvent>
void	consumesMany ()
void	consumesMany (const TypeToGet &id)
template<BranchType B>
void	consumesMany (const TypeToGet &id)
template<typename ESProduct , typename ESRecord , Transition Tr = Transition::Event>
auto	esConsumes ()
template<typename ESProduct , typename ESRecord , Transition Tr = Transition::Event>
auto	esConsumes (ESInputTag const &tag)
EDGetToken	mayConsume (const TypeToGet &id, edm::InputTag const &tag)
template<BranchType B>
EDGetToken	mayConsume (const TypeToGet &id, edm::InputTag const &tag)
template<typename ProductType , BranchType B = InEvent>
EDGetTokenT< ProductType >	mayConsume (edm::InputTag const &tag)

Detailed Description

Description: Class to examine boosted ttbar pairs in multiple mass regions.

This will produce a ttbar solution, which will take one of two forms: a) lv jj jj Full reconstruction.

ttbar-> (hadt -> (hadW -> hadp + hadq) + hadb) + (lept -> (lepW -> lepton + neutrino) + lepb)

b) lv jj (j) Partial reconstruction, associate at least 1 jet to the lepton hemisphere, and at least one jet in the opposite hemisphere.

ttbar-> (hadt -> (hadJet1 [+ hadJet2] ) ) + (lept -> (lepW -> lepton + neutrino) + lepJet1 )

There will also be two subcategories of (b) that will correspond to physics cases:

b1) Lepton is isolated: Moderate ttbar mass. b2) Lepton is nonisolated: High ttbar mass.

Implementation: To implement this, we use the NamedCompositeCandidate structures from the Candidate model. This provides flexibility in the definition of the output objects and allows automatic plotting in the Starter Kit. We use the PAT objects to construct the ttbar solutions in the different ranges as follows: a) Full reconstruction: We use TtSemiEventSolutions made upstream of this module. b) Partial reconstruction: Association of variables using the "Psi" variable, which is a more rapidity-invariant version of deltaR.

Definition at line 80 of file BoostedTopProducer.h.

Constructor & Destructor Documentation

BoostedTopProducer()

BoostedTopProducer::BoostedTopProducer ( const edm::ParameterSet &  iConfig )

explicit

Definition at line 23 of file BoostedTopProducer.cc.

    : eleToken_(consumes<std::vector<pat::Electron> >(iConfig.getParameter<edm::InputTag>("electronLabel"))),
      muoToken_(consumes<std::vector<pat::Muon> >(iConfig.getParameter<edm::InputTag>("muonLabel"))),
      jetToken_(consumes<std::vector<pat::Jet> >(iConfig.getParameter<edm::InputTag>("jetLabel"))),
      metToken_(consumes<std::vector<pat::MET> >(iConfig.getParameter<edm::InputTag>("metLabel"))),
      solToken_(mayConsume<TtSemiLeptonicEvent>(iConfig.getParameter<edm::InputTag>("solLabel"))),
      caloIsoCut_(iConfig.getParameter<double>("caloIsoCut")),
      mTop_(iConfig.getParameter<double>("mTop")) {
  //register products
  produces<std::vector<reco::CompositeCandidate> >();
}

~BoostedTopProducer()

BoostedTopProducer::~BoostedTopProducer ( )

override

Definition at line 35 of file BoostedTopProducer.cc.

{}

Member Function Documentation

produce()

void BoostedTopProducer::produce ( edm::Event &  iEvent, const edm::EventSetup &  iSetup  )

overrideprivatevirtual

Implements edm::EDProducer.

Definition at line 42 of file BoostedTopProducer.cc.

                                                                              {
  using namespace edm;
 
  bool debug = false;
 
  // -----------------------------------------------------
  // get the bare PAT objects
  // -----------------------------------------------------
  edm::Handle<std::vector<pat::Muon> > muonHandle;
  iEvent.getByToken(muoToken_, muonHandle);
  std::vector<pat::Muon> const& muons = *muonHandle;
 
  edm::Handle<std::vector<pat::Jet> > jetHandle;
  iEvent.getByToken(jetToken_, jetHandle);
  std::vector<pat::Jet> const& jets = *jetHandle;
 
  edm::Handle<std::vector<pat::Electron> > electronHandle;
  iEvent.getByToken(eleToken_, electronHandle);
  std::vector<pat::Electron> const& electrons = *electronHandle;
 
  edm::Handle<std::vector<pat::MET> > metHandle;
  iEvent.getByToken(metToken_, metHandle);
  std::vector<pat::MET> const& mets = *metHandle;
 
  // -----------------------------------------------------
  // Event Preselection:
  //    <= 1 isolated electron or muon
  //    >= 1 electron or muon
  //    >= 2 jets
  //    >= 1 missing et
  //
  // To explain:
  //    We want to look at leptons within "top jets" in some
  //    cases. This means the isolation will kill those events.
  //    However, if there IS an isolated lepton, we want only
  //    one of them.
  //
  //    So to select the prompt W lepton, the logic is:
  //    1. If there is an isolated lepton, accept it as the W lepton.
  //    2. Else, take the highest Pt lepton (possibly non-isolated)
  //
  // -----------------------------------------------------
  bool preselection = true;
 
  // This will hold the prompt W lepton candidate, and a
  // maximum pt decision variable
  double maxWLeptonPt = -1;
  //reco::Candidate const * Wlepton = 0;
 
  // ----------------------
  // Find isolated muons, and highest pt lepton
  // ----------------------
  std::vector<pat::Muon>::const_iterator isolatedMuon = muons.end();
  std::vector<pat::Muon>::const_iterator muon = muons.end();
  unsigned int nIsolatedMuons = 0;
  std::vector<pat::Muon>::const_iterator muonIt = muons.begin(), muonEnd = muons.end();
  for (; muonIt != muonEnd; ++muonIt) {
    // Find highest pt lepton
    double pt = muonIt->pt();
    if (pt > maxWLeptonPt) {
      maxWLeptonPt = pt;
      muon = muonIt;
    }
 
    // Find any isolated muons
    double caloIso = muonIt->caloIso();
    if (caloIso >= 0 && caloIso < caloIsoCut_) {
      nIsolatedMuons++;
      isolatedMuon = muonIt;
    }
  }
 
  // ----------------------
  // Find isolated electrons, and highest pt lepton
  // ----------------------
  std::vector<pat::Electron>::const_iterator isolatedElectron = electrons.end();
  std::vector<pat::Electron>::const_iterator electron = electrons.end();
  unsigned int nIsolatedElectrons = 0;
  std::vector<pat::Electron>::const_iterator electronIt = electrons.begin(), electronEnd = electrons.end();
  for (; electronIt != electronEnd; ++electronIt) {
    // Find highest pt lepton
    double pt = electronIt->pt();
    if (pt > maxWLeptonPt) {
      maxWLeptonPt = pt;
      electron = electronIt;
    }
 
    // Find any isolated electrons
    double caloIso = electronIt->caloIso();
    if (caloIso >= 0 && caloIso < caloIsoCut_) {
      nIsolatedElectrons++;
      isolatedElectron = electronIt;
    }
  }
 
  // ----------------------
  // Now decide on the "prompt" lepton from the W:
  // Choose isolated leptons over all, and if no isolated,
  // then take highest pt lepton.
  // ----------------------
  bool isMuon = true;
  if (isolatedMuon != muonEnd) {
    muon = isolatedMuon;
    isMuon = true;
  } else if (isolatedElectron != electronEnd) {
    electron = isolatedElectron;
    isMuon = false;
  } else {
    // Set to the highest pt lepton
    if (muon != muonEnd && electron == electronEnd)
      isMuon = true;
    else if (muon == muonEnd && electron != electronEnd)
      isMuon = false;
    else if (muon != muonEnd && electron != electronEnd) {
      isMuon = muon->pt() > electron->pt();
    }
  }
 
  // ----------------------
  // Veto events that have more than one isolated lepton
  // ----------------------
  int nIsolatedLeptons = nIsolatedMuons + nIsolatedElectrons;
  if (nIsolatedLeptons > 1) {
    preselection = false;
  }
 
  // ----------------------
  // Veto events that have no prompt lepton candidates
  // ----------------------
  if (muon == muonEnd && electron == electronEnd) {
    preselection = false;
  }
 
  // ----------------------
  // Veto events with < 2 jets or no missing et
  // ----------------------
  if (jets.size() < 2 || mets.empty()) {
    preselection = false;
  }
 
  bool write = false;
 
  // -----------------------------------------------------
  //
  // CompositeCandidates to store the event solution.
  // This will take one of two forms:
  //    a) lv jj jj   Full reconstruction.
  //
  //   ttbar->
  //       (hadt -> (hadW -> hadp + hadq) + hadb) +
  //       (lept -> (lepW -> lepton + neutrino) + lepb)
  //
  //    b) lv jj (j)  Partial reconstruction, associate
  //                  at least 1 jet to the lepton
  //                  hemisphere, and at least one jet in
  //                  the opposite hemisphere.
  //
  //    ttbar->
  //        (hadt -> (hadJet1 [+ hadJet2] ) ) +
  //        (lept -> (lepW -> lepton + neutrino) + lepJet1 )
  //
  // There will also be two subcategories of (b) that
  // will correspond to physics cases:
  //
  //    b1)           Lepton is isolated: Moderate ttbar mass.
  //    b2)           Lepton is nonisolated: High ttbar mass.
  //
  // -----------------------------------------------------
  reco::CompositeCandidate ttbar("ttbar");
  AddFourMomenta addFourMomenta;
 
  // Main decisions after preselection
  if (preselection) {
    if (debug)
      cout << "Preselection is satisfied" << endl;
 
    if (debug)
      cout << "Jets.size() = " << jets.size() << endl;
 
    // This will be modified for the z solution, so make a copy
    pat::MET neutrino(mets[0]);
 
    // 1. First examine the low mass case with 4 jets and widely separated
    //    products. We take out the TtSemiLeptonicEvent from the TQAF and
    //    form the ttbar invariant mass.
    if (jets.size() >= 4) {
      if (debug)
        cout << "Getting ttbar semileptonic solution" << endl;
 
      // get the ttbar semileptonic event solution if there are more than 3 jets
      edm::Handle<TtSemiLeptonicEvent> eSol;
      iEvent.getByToken(solToken_, eSol);
 
      // Have solution, continue
      if (eSol.isValid()) {
        if (debug)
          cout << "Got a nonzero size solution vector" << endl;
        // Just set the ttbar solution to the best ttbar solution from
        // TtSemiEvtSolutionMaker
        ttbar = eSol->eventHypo(TtSemiLeptonicEvent::kMVADisc);
        write = true;
      }
      // No ttbar solution with 4 jets, something is weird, print a warning
      else {
        edm::LogWarning("DataNotFound") << "BoostedTopProducer: Cannot find TtSemiEvtSolution\n";
      }
    }
    // 2. With 2 or 3 jets, we decide based on the separation between
    // the lepton and the closest jet in that hemisphere whether to
    // consider it "moderate" or "high" mass.
    else if (jets.size() == 2 || jets.size() == 3) {
      // ------------------------------------------------------------------
      // First create a leptonic W candidate
      // ------------------------------------------------------------------
      reco::CompositeCandidate lepW("lepW");
 
      if (isMuon) {
        if (debug)
          cout << "Adding muon as daughter" << endl;
        lepW.addDaughter(*muon, "muon");
      } else {
        if (debug)
          cout << "Adding electron as daughter" << endl;
        lepW.addDaughter(*electron, "electron");
      }
      if (debug)
        cout << "Adding neutrino as daughter" << endl;
      lepW.addDaughter(neutrino, "neutrino");
      addFourMomenta.set(lepW);
 
      //bool nuzHasComplex = false;
      METzCalculator zcalculator;
 
      zcalculator.SetMET(neutrino);
      if (isMuon)
        zcalculator.SetMuon(*muon);
      else
        zcalculator.SetMuon(*electron);              // This name is misleading, should be setLepton
      double neutrinoPz = zcalculator.Calculate(1);  // closest to the lepton Pz
      //if (zcalculator.IsComplex()) nuzHasComplex = true;
      // Set the neutrino pz
      neutrino.setPz(neutrinoPz);
 
      if (debug)
        cout << "Set neutrino pz to " << neutrinoPz << endl;
 
      // ------------------------------------------------------------------
      // Next ensure that there is a jet within the hemisphere of the
      // leptonic W, and one in the opposite hemisphere
      // ------------------------------------------------------------------
      reco::CompositeCandidate hadt("hadt");
      reco::CompositeCandidate lept("lept");
      if (debug)
        cout << "Adding lepW as daughter" << endl;
      lept.addDaughter(lepW, "lepW");
 
      std::string hadName("hadJet");
      std::string lepName("lepJet");
 
      // Get the W momentum
      TLorentzVector p4_W(lepW.px(), lepW.py(), lepW.pz(), lepW.energy());
 
      // Loop over the jets
      std::vector<pat::Jet>::const_iterator jetit = jets.begin(), jetend = jets.end();
      unsigned long ii = 1;  // Count by 1 for naming histograms
      for (; jetit != jetend; ++jetit, ++ii) {
        // Get this jet's momentum
        TLorentzVector p4_jet(jetit->px(), jetit->py(), jetit->pz(), jetit->energy());
 
        // Calculate psi (like DeltaR, only more invariant under Rapidity)
        double psi = Psi(p4_W, p4_jet, mTop_);
 
        // Get jets that are in the leptonic hemisphere
        if (psi < TMath::Pi()) {
          // Add this jet to the leptonic top
          std::stringstream s;
          s << lepName << ii;
          if (debug)
            cout << "Adding daughter " << s.str() << endl;
          lept.addDaughter(*jetit, s.str());
        }
        // Get jets that are in the hadronic hemisphere
        if (psi > TMath::Pi()) {
          // Add this jet to the hadronic top. We don't
          // make any W hypotheses in this case, since
          // we cannot determine which of the three
          // jets are merged.
          std::stringstream s;
          s << hadName << ii;
          if (debug)
            cout << "Adding daughter " << s.str() << endl;
          hadt.addDaughter(*jetit, s.str());
        }
      }  // end loop over jets
 
      addFourMomenta.set(lept);
      addFourMomenta.set(hadt);
 
      bool lepWHasJet = lept.numberOfDaughters() >= 2;  // W and >= 1 jet
      bool hadWHasJet = hadt.numberOfDaughters() >= 1;  // >= 1 jet
      if (lepWHasJet && hadWHasJet) {
        if (debug)
          cout << "Adding daughters lept and hadt" << endl;
        ttbar.addDaughter(lept, "lept");
        ttbar.addDaughter(hadt, "hadt");
        addFourMomenta.set(ttbar);
        write = true;
      }  // end of hadronic jet and leptonic jet
 
    }  // end if there are 2 or 3 jets
 
  }  // end if preselection is satisfied
 
  // Write the solution to the event record
  std::vector<reco::CompositeCandidate> ttbarList;
  if (write) {
    if (debug)
      cout << "Writing out" << endl;
    ttbarList.push_back(ttbar);
  }
  std::unique_ptr<std::vector<reco::CompositeCandidate> > pTtbar(new std::vector<reco::CompositeCandidate>(ttbarList));
  iEvent.put(std::move(pTtbar));
}

References reco::CompositeCandidate::addDaughter(), METzCalculator::Calculate(), caloIsoCut_, gather_cfg::cout, debug, HPSPFTauProducerPuppi_cfi::electron, pwdgSkimBPark_cfi::electrons, eleToken_, reco::LeafCandidate::energy(), TtEvent::eventHypo(), iEvent, cuy::ii, reco::isMuon(), edm::HandleBase::isValid(), singleTopDQM_cfi::jets, jetToken_, TtEvent::kMVADisc, singleTopDQM_cfi::mets, metToken_, eostools::move(), mTop_, PDWG_BPHSkim_cff::muons, muoToken_, reco::CompositeCandidate::numberOfDaughters(), Pi, singleTopDQM_cfi::preselection, Psi(), DiDispStaMuonMonitor_cfi::pt, reco::LeafCandidate::px(), reco::LeafCandidate::py(), reco::LeafCandidate::pz(), alignCSCRings::s, AddFourMomenta::set(), METzCalculator::SetMET(), METzCalculator::SetMuon(), reco::LeafCandidate::setPz(), solToken_, AlCaHLTBitMon_QueryRunRegistry::string, and writeEcalDQMStatus::write.

Psi()

double BoostedTopProducer::Psi ( const TLorentzVector &  p1, const TLorentzVector &  p2, double  mass  )

private

Definition at line 366 of file BoostedTopProducer.cc.

                                                                                              {
  TLorentzVector ptot = p1 + p2;
  Double_t theta1 = TMath::ACos((p1.Vect().Dot(ptot.Vect())) / (p1.P() * ptot.P()));
  Double_t theta2 = TMath::ACos((p2.Vect().Dot(ptot.Vect())) / (p2.P() * ptot.P()));
  //Double_t sign = 1.;
  //if ( (theta1+theta2) > (TMath::Pi()/2) ) sign = -1.;
  double th1th2 = theta1 + theta2;
  double psi = (p1.P() + p2.P()) * TMath::Abs(TMath::Sin(th1th2)) / (2. * mass);
  if (th1th2 > (TMath::Pi() / 2))
    psi = (p1.P() + p2.P()) * (1. + TMath::Abs(TMath::Cos(th1th2))) / (2. * mass);
 
  return psi;
}

References Abs(), EgHLTOffHistBins_cfi::mass, p1, p2, and Pi.

Referenced by produce().

Member Data Documentation

caloIsoCut_

double BoostedTopProducer::caloIsoCut_

private

Definition at line 98 of file BoostedTopProducer.h.

Referenced by produce().

eleToken_

edm::EDGetTokenT<std::vector<pat::Electron> > BoostedTopProducer::eleToken_

private

Definition at line 91 of file BoostedTopProducer.h.

Referenced by produce().

jetToken_

edm::EDGetTokenT<std::vector<pat::Jet> > BoostedTopProducer::jetToken_

private

Definition at line 93 of file BoostedTopProducer.h.

Referenced by produce().

metToken_

edm::EDGetTokenT<std::vector<pat::MET> > BoostedTopProducer::metToken_

private

Definition at line 94 of file BoostedTopProducer.h.

Referenced by produce().

mTop_

double BoostedTopProducer::mTop_

private

Definition at line 99 of file BoostedTopProducer.h.

Referenced by produce().

muoToken_

edm::EDGetTokenT<std::vector<pat::Muon> > BoostedTopProducer::muoToken_

private

Definition at line 92 of file BoostedTopProducer.h.

Referenced by produce().

solToken_

edm::EDGetTokenT<TtSemiLeptonicEvent> BoostedTopProducer::solToken_

private

Definition at line 95 of file BoostedTopProducer.h.

Referenced by produce().