TICL/plugins/TracksterLinkingbyFastJet.cc

0001 #include "RecoHGCal/TICL/interface/TracksterLinkingAlgoBase.h"
0002 #include "fastjet/ClusterSequence.hh"
0003 #include "DataFormats/Math/interface/deltaR.h"
0004 #include "RecoHGCal/TICL/plugins/TracksterLinkingbyFastJet.h"
0005
0006 using namespace ticl;
0007
0008 void TracksterLinkingbyFastJet::linkTracksters(
0009     const Inputs& input,
0010     std::vector<Trackster>& resultTracksters,
0011     std::vector<std::vector<unsigned int>>& linkedResultTracksters,
0012     std::vector<std::vector<unsigned int>>& linkedTracksterIdToInputTracksterId) {
0013   // Create jets of tracksters using FastJet
0014   std::vector<fastjet::PseudoJet> fjInputs;
0015   for (size_t i = 0; i < input.tracksters.size(); ++i) {
0016     // Convert Trackster information to PseudoJet
0017     fastjet::PseudoJet pj(input.tracksters[i].barycenter().x(),
0018                           input.tracksters[i].barycenter().y(),
0019                           input.tracksters[i].barycenter().z(),
0020                           input.tracksters[i].raw_energy());
0021     pj.set_user_index(i);
0022     fjInputs.push_back(pj);
0023   }
0024
0025   // Cluster tracksters into jets using FastJet
0026   fastjet::ClusterSequence sequence(fjInputs, fastjet::JetDefinition(algorithm_, radius_));
0027   auto jets = fastjet::sorted_by_pt(sequence.inclusive_jets(0));
0028   linkedTracksterIdToInputTracksterId.resize(jets.size());
0029   // Link tracksters based on which ones are components of the same jet
0030   for (unsigned int i = 0; i < jets.size(); ++i) {
0031     const auto& jet = jets[i];
0032
0033     std::vector<unsigned int> linkedTracksters;
0034     Trackster outTrackster;
0035     if (!jet.constituents().empty()) {
0036       // Check if a trackster is a component of the current jet
0037       for (const auto& constituent : jet.constituents()) {
0038         auto tracksterIndex = constituent.user_index();
0039         linkedTracksterIdToInputTracksterId[i].push_back(tracksterIndex);
0040         outTrackster.mergeTracksters(input.tracksters[tracksterIndex]);
0041       }
0042       linkedTracksters.push_back(resultTracksters.size());
0043       resultTracksters.push_back(outTrackster);
0044       // Store the linked tracksters
0045       linkedResultTracksters.push_back(linkedTracksters);
0046     }
0047   }
0048 }