Produces reco::GenParticle from SimTracks. More...

Inheritance diagram for pat::GenPlusSimParticleProducer:

Classes
struct	LessById
Public Member Functions
	GenPlusSimParticleProducer (const edm::ParameterSet &)
	~GenPlusSimParticleProducer ()
Private Types
typedef StringCutObjectSelector < reco::GenParticle >	StrFilter
Private Member Functions
void	addGenParticle (const SimTrack &stMom, const SimTrack &stDau, unsigned int momidx, const edm::SimTrackContainer &simtks, const edm::SimVertexContainer &simvtxs, reco::GenParticleCollection &mergedGens, const reco::GenParticleRefProd ref, std::vector< int > &genBarcodes, bool &barcodesAreSorted) const
	Try to link the GEANT particle to the generator particle it came from.
virtual void	endJob ()
virtual void	produce (edm::Event &, const edm::EventSetup &)
Private Attributes
std::auto_ptr< StrFilter >	filter_
bool	firstEvent_
edm::InputTag	genParticles_
	Collection of GenParticles I need to make refs to. It must also have its associated vector<int> of barcodes, aligned with them.
std::set< int >	pdgIds_
std::vector< PdtEntry >	pdts_
int	setStatus_
edm::InputTag	src_

Detailed Description

Produces reco::GenParticle from SimTracks.

The GenPlusSimParticleProducer produces GenParticles from SimTracks, so they can be used for MC matching. A copy of the original genParticle list is made and the genParticles created from the GEANT/FAMOS particles are added to the list including all ancestors and correct mother/daughter references

Sample useage in cfg.py file: process.genParticlePlusGEANT = cms.EDProducer("GenPlusSimParticleProducer", src = cms.InputTag("g4SimHits"), # use "famosSimHits" for FAMOS setStatus = cms.int32(8), # set status = 8 for GEANT GPs particleTypes = cms.vstring("pi+"), # also picks pi- (optional) filter = cms.vstring("pt > 0.0"), # just for testing genParticles = cms.InputTag("genParticles") # original genParticle list )

Author:: Jordan Tucker (original module), Keith Ulmer (generalization)

Definition at line 39 of file GenPlusSimParticleProducer.cc.

Member Typedef Documentation

typedef StringCutObjectSelector<reco::GenParticle> pat::GenPlusSimParticleProducer::StrFilter [private]

Definition at line 54 of file GenPlusSimParticleProducer.cc.

Constructor & Destructor Documentation

GenPlusSimParticleProducer::GenPlusSimParticleProducer ( const edm::ParameterSet & cfg ) [explicit]

Definition at line 97 of file GenPlusSimParticleProducer.cc.

References edm::ParameterSet::exists(), edm::ParameterSet::existsAs(), alcazmumu_cfi::filter, filter_, edm::ParameterSet::getParameter(), and pdts_.

                                                                              :
  firstEvent_(true),
  src_(cfg.getParameter<InputTag>("src")),            // source sim tracks & vertices
  setStatus_(cfg.getParameter<int32_t>("setStatus")), // set status of GenParticle to this code
  genParticles_(cfg.getParameter<InputTag>("genParticles")) // get the genParticles to add GEANT particles to
{
  // Possibly allow a list of particle types
  if (cfg.exists("particleTypes")) {
    pdts_ = cfg.getParameter<vector<PdtEntry> >("particleTypes");
  }
  
  // Possibly allow a string cut
  if (cfg.existsAs<string>("filter")) {
    string filter = cfg.getParameter<string>("filter");
    if (!filter.empty()) {
      filter_ = auto_ptr<StrFilter>(new StrFilter(filter));
    }
  }
  produces<GenParticleCollection>();
  produces<vector<int> >();
}

pat::GenPlusSimParticleProducer::~GenPlusSimParticleProducer ( ) [inline]

Definition at line 42 of file GenPlusSimParticleProducer.cc.

{}

Member Function Documentation

void GenPlusSimParticleProducer::addGenParticle	(	const SimTrack &	stMom,
		const SimTrack &	stDau,
		unsigned int	momidx,
		const edm::SimTrackContainer &	simtks,
		const edm::SimVertexContainer &	simvtxs,
		reco::GenParticleCollection &	mergedGens,
		const reco::GenParticleRefProd	ref,
		std::vector< int > &	genBarcodes,
		bool &	barcodesAreSorted
	)		const `[private]`

Try to link the GEANT particle to the generator particle it came from.

Arguments: -- Specific -- gp: GenParticle made from the GEANT particle st: The GEANT simTrack for which we create a genParticle

-- GEANT related -- simtks: A list of GEANT tracks, sorted by track id simvtxs: The list of GEANT vertices, in their natural order (skimtks have pointers into this vector!)

-- GenParticle related -- gens : Handle to the GenParticles, to make the ref to genBarcodes : Barcodes for each GenParticle, in a vector aligned to the GenParticleCollection. barcodesAreSorted: true if the barcodes are sorted (which means I can use binary_search on them)

Definition at line 119 of file GenPlusSimParticleProducer.cc.

References reco::CompositeRefCandidateT< D >::addDaughter(), CoreSimTrack::charge(), DeDxDiscriminatorTools::charge(), filter_, EgammaValidation_cff::genp, CoreSimTrack::momentum(), SimVertex::noParent(), SimTrack::noVertex(), p4, SimVertex::parentIndex(), setStatus_, CoreSimTrack::trackId(), CoreSimTrack::type(), and SimTrack::vertIndex().

Referenced by produce().

{
  // Make the genParticle for stDau and add it to the new collection and update the parent-child relationship
  // Make up a GenParticleCandidate from the GEANT track info.
  int charge = static_cast<int>(stDau.charge());
  Particle::LorentzVector p4 = stDau.momentum();
  Particle::Point vtx; // = (0,0,0) by default
  if (!stDau.noVertex()) vtx = simvertices[stDau.vertIndex()].position();
  GenParticle genp(charge, p4, vtx, stDau.type(), setStatus_, true);
  
  // Maybe apply filter on the particle
  if (filter_.get() != 0) {
    if (!(*filter_)(genp)) return;
  }
  
  reco::GenParticleRef parentRef(ref, momidx);
  genp.addMother(parentRef);
  mergedGens.push_back(genp);
  // get the index for the daughter just added
  unsigned int dauidx = mergedGens.size()-1;

  // update add daughter relationship
  reco::GenParticle & cand = mergedGens[ momidx ];
  cand.addDaughter( GenParticleRef( ref, dauidx) );

  //look for simtrack daughters of stDau to see if we need to recur further down the chain
  
  for (SimTrackContainer::const_iterator isimtrk = simtracksSorted.begin();
       isimtrk != simtracksSorted.end(); ++isimtrk) {
    if (!isimtrk->noVertex()) {
      // Pick the vertex (isimtrk.vertIndex() is really an index)
      const SimVertex &vtx = simvertices[isimtrk->vertIndex()];
      
      // Check if the vertex has a parent track (otherwise, we're lost)
      if (!vtx.noParent()) {
        
        // Now note that vtx.parentIndex() is NOT an index, it's a track id, so I have to search for it 
        unsigned int idx = vtx.parentIndex();
        SimTrackContainer::const_iterator it = std::lower_bound(simtracksSorted.begin(), simtracksSorted.end(), idx, LessById());
        if ((it != simtracksSorted.end()) && (it->trackId() == idx)) {
          if (it->trackId()==stDau.trackId()) {
            //need the genparticle index of stDau which is dauidx
            addGenParticle(stDau, *isimtrk, dauidx, simtracksSorted, simvertices, mergedGens, ref, genBarcodes, barcodesAreSorted);
          }
        }
      }
    }
  }
}

virtual void pat::GenPlusSimParticleProducer::endJob ( void ) [inline, private, virtual]

Reimplemented from edm::EDProducer.

Definition at line 46 of file GenPlusSimParticleProducer.cc.

{}

void GenPlusSimParticleProducer::produce	(	edm::Event &	event,
		const edm::EventSetup &	iSetup
	)		`[private, virtual]`

Implements edm::EDProducer.

Definition at line 177 of file GenPlusSimParticleProducer.cc.

                                                                      {
  if (firstEvent_){
    if (!pdts_.empty()) {
      pdgIds_.clear();
      for (vector<PdtEntry>::iterator itp = pdts_.begin(), edp = pdts_.end(); itp != edp; ++itp) {
        itp->setup(iSetup); // decode string->pdgId and vice-versa                                                                                                      
        pdgIds_.insert(std::abs(itp->pdgId()));
      }
      pdts_.clear();
    }
    firstEvent_ = false;
  }

  // Simulated tracks (i.e. GEANT particles).
  Handle<SimTrackContainer> simtracks;
  event.getByLabel(src_, simtracks);
  
  // Need to check that SimTrackContainer is sorted; otherwise, copy and sort :-(
  std::auto_ptr<SimTrackContainer> simtracksTmp;
  const SimTrackContainer * simtracksSorted = &* simtracks;
  if (!__gnu_cxx::is_sorted(simtracks->begin(), simtracks->end(), LessById())) {
    simtracksTmp.reset(new SimTrackContainer(*simtracks));
    std::sort(simtracksTmp->begin(), simtracksTmp->end(), LessById());
    simtracksSorted = &* simtracksTmp;
  }
  
  // Get the associated vertices
  Handle<SimVertexContainer> simvertices;
  event.getByLabel(src_, simvertices);
  
  // Get the GenParticles and barcodes, if needed to set mother and daughter links
  Handle<GenParticleCollection> gens;
  Handle<std::vector<int> > genBarcodes;
  bool barcodesAreSorted = true;
  event.getByLabel(genParticles_, gens);
  event.getByLabel(genParticles_, genBarcodes);
  if (gens->size() != genBarcodes->size()) throw cms::Exception("Corrupt data") << "Barcodes not of the same size as GenParticles!\n";
  
  // make the output collection
  auto_ptr<GenParticleCollection> candsPtr(new GenParticleCollection);
  GenParticleCollection & cands = * candsPtr;
  
  const GenParticleRefProd ref = event.getRefBeforePut<GenParticleCollection>();
  
  // add the original genParticles to the merged output list
  for( size_t i = 0; i < gens->size(); ++ i ) {
    reco::GenParticle cand((*gens)[i]);
    cands.push_back(cand);
  }
  
  // make new barcodes vector and fill it with the original list
  auto_ptr<vector<int> > newGenBarcodes( new vector<int>() );
  for (unsigned int i = 0; i < genBarcodes->size(); ++i) {
    newGenBarcodes->push_back((*genBarcodes)[i]);
  }
  barcodesAreSorted = __gnu_cxx::is_sorted(newGenBarcodes->begin(), newGenBarcodes->end());
  
  for( size_t i = 0; i < cands.size(); ++ i ) {
    reco::GenParticle & cand = cands[ i ];
    size_t nDaus = cand.numberOfDaughters();
    GenParticleRefVector daus = cand.daughterRefVector();
    cand.resetDaughters( ref.id() );
    for ( size_t d = 0; d < nDaus; ++d) {
      cand.addDaughter( GenParticleRef( ref, daus[d].key() ) );
    }
    
    size_t nMoms = cand.numberOfMothers();
    GenParticleRefVector moms = cand.motherRefVector();
    cand.resetMothers( ref.id() );
    for ( size_t m = 0; m < nMoms; ++m) {
      cand.addMother( GenParticleRef( ref, moms[m].key() ) );
    }
  }
  
  for (SimTrackContainer::const_iterator isimtrk = simtracks->begin();
       isimtrk != simtracks->end(); ++isimtrk) {
    
    // Skip PYTHIA tracks.
    if (isimtrk->genpartIndex() != -1) continue; 
    
    // Maybe apply the PdgId filter
    if (!pdgIds_.empty()) { // if we have a filter on pdg ids
      if (pdgIds_.find(std::abs(isimtrk->type())) == pdgIds_.end()) continue;
    }
    
    // find simtrack that has a genParticle match to its parent
    // Look at the production vertex. If there is no vertex, I can do nothing...
    if (!isimtrk->noVertex()) {
      
      // Pick the vertex (isimtrk.vertIndex() is really an index)
      const SimVertex &vtx = (*simvertices)[isimtrk->vertIndex()];
      
      // Check if the vertex has a parent track (otherwise, we're lost)
      if (!vtx.noParent()) {
        
        // Now note that vtx.parentIndex() is NOT an index, it's a track id, so I have to search for it 
        unsigned int idx = vtx.parentIndex();
        SimTrackContainer::const_iterator it = std::lower_bound(simtracksSorted->begin(), simtracksSorted->end(), idx, LessById());
        if ((it != simtracksSorted->end()) && (it->trackId() == idx)) { //it is the parent sim track
          if (it->genpartIndex() != -1) {
            std::vector<int>::const_iterator itIndex;
            if (barcodesAreSorted) {
              itIndex = std::lower_bound(genBarcodes->begin(), genBarcodes->end(), it->genpartIndex());
            } else {
              itIndex = std::find(       genBarcodes->begin(), genBarcodes->end(), it->genpartIndex());
            }
            
            // Check that I found something
            // I need to check '*itIndex == it->genpartIndex()' because lower_bound just finds the right spot for an item in a sorted list, not the item
            if ((itIndex != genBarcodes->end()) && (*itIndex == it->genpartIndex())) {
              // Ok, I'll make the genParticle for st and add it to the new collection updating the map and parent-child relationship
              // pass the mother and daughter sim tracks and the mother genParticle to method to create the daughter genParticle and recur
              unsigned int momidx = itIndex - genBarcodes->begin();
              addGenParticle(*it, *isimtrk, momidx, *simtracksSorted, *simvertices, *candsPtr, ref, *newGenBarcodes, barcodesAreSorted);
            }
          }
        }
      }
    }   
  }
  
  event.put(candsPtr);
  event.put(newGenBarcodes);
}