File indexing completed on 2024-04-06 12:24:08
0001 #include "PhysicsTools/RecoUtils/interface/CandCommonVertexFitter.h"
0002 #include "DataFormats/GsfTrackReco/interface/GsfTrack.h"
0003 #include "DataFormats/Candidate/interface/VertexCompositeCandidate.h"
0004 #include "FWCore/Utilities/interface/EDMException.h"
0005 #include <sstream>
0006 using namespace reco;
0007 using namespace std;
0008
0009 void CandCommonVertexFitterBase::set(VertexCompositeCandidate &c) const {
0010 if (bField_ == nullptr)
0011 throw edm::Exception(edm::errors::InvalidReference)
0012 << "B-Field was not set up CandCommonVertexFitter.\n"
0013 << "the following method must be called before fitting a candidate:\n"
0014 << " CandCommonVertexFitter:.set( const MagneticField * )" << endl;
0015 vector<TransientTrack> tracks;
0016 vector<Candidate *> daughters;
0017 vector<RecoCandidate::TrackType> trackTypes;
0018 fill(tracks, daughters, trackTypes, c);
0019 assert(tracks.size() == daughters.size());
0020 TransientVertex vertex;
0021 if (fit(vertex, tracks)) {
0022 tracks = vertex.refittedTracks();
0023 Candidate::Point vtx(vertex.position());
0024 c.setVertex(vtx);
0025 vector<TransientTrack>::const_iterator trackIt = tracks.begin(), tracksEnd = tracks.end();
0026 vector<Candidate *>::const_iterator daughterIt = daughters.begin();
0027 vector<RecoCandidate::TrackType>::const_iterator trackTypeIt = trackTypes.begin();
0028 Candidate::LorentzVector mp4(0, 0, 0, 0);
0029 for (; trackIt != tracksEnd; ++trackIt, ++daughterIt, ++trackTypeIt) {
0030 const Track &track = trackIt->track();
0031 Candidate &daughter = **daughterIt;
0032 double px = track.px(), py = track.py(), pz = track.pz(), p = track.p();
0033 double energy;
0034 daughter.setVertex(vtx);
0035 if (*trackTypeIt == RecoCandidate::recoTrackType) {
0036 double mass = daughter.mass();
0037 energy = sqrt(p * p + mass * mass);
0038 } else {
0039 energy = daughter.energy();
0040 double scale = energy / p;
0041 px *= scale;
0042 py *= scale;
0043 pz *= scale;
0044 }
0045 Candidate::LorentzVector dp4(px, py, pz, energy);
0046 daughter.setP4(dp4);
0047 mp4 += dp4;
0048 }
0049 c.setP4(mp4);
0050 Vertex v = vertex;
0051 c.setChi2AndNdof(chi2_ = v.chi2(), ndof_ = v.ndof());
0052 v.fill(cov_);
0053 c.setCovariance(cov_);
0054 } else {
0055 c.setChi2AndNdof(chi2_ = -1, ndof_ = 0);
0056 c.setCovariance(cov_ = CovarianceMatrix(ROOT::Math::SMatrixIdentity()));
0057 }
0058 }
0059
0060 void CandCommonVertexFitterBase::fill(vector<TransientTrack> &tracks,
0061 vector<Candidate *> &daughters,
0062 vector<RecoCandidate::TrackType> &trackTypes,
0063 Candidate &c) const {
0064 size_t nDau = c.numberOfDaughters();
0065 for (unsigned int j = 0; j < nDau; ++j) {
0066 Candidate *d = c.daughter(j);
0067 if (d == nullptr) {
0068 ostringstream message;
0069 message << "Can't access in write mode candidate daughters. "
0070 << "pdgId = " << c.pdgId() << ".\n";
0071 const Candidate *d1 = c.daughter(j);
0072 if (d1 == nullptr)
0073 message << "Null daughter also found in read-only mode\n";
0074 else
0075 message << "Daughter found in read-only mode with id: " << d1->pdgId() << "\n";
0076 throw edm::Exception(edm::errors::InvalidReference) << message.str();
0077 }
0078 if (d->numberOfDaughters() > 0)
0079 fill(tracks, daughters, trackTypes, *d);
0080 else {
0081 const Track *trk = d->get<const Track *>();
0082 RecoCandidate::TrackType type = d->get<RecoCandidate::TrackType>();
0083 if (trk != nullptr) {
0084 tracks.push_back(TransientTrack(*trk, bField_));
0085 daughters.push_back(d);
0086 trackTypes.push_back(type);
0087 } else {
0088 cerr << ">>> warning: candidate of type " << d->pdgId() << " has no track reference." << endl;
0089 }
0090 }
0091 }
0092 }
