PWGLF: Add GeneratorLFLnnPbPb.ini and lnn_pbpb.gun files (#1774)

* PWGLF: Add GeneratorLFLnnPbPb.ini and lnn_pbpb.gun files

* add GeneratorLnnPbPb.C

* Fix configuration

MC/config/PWGLF/ini/GeneratorLFLnnPbPb.ini

@@ -0,0 +1,6 @@
+[GeneratorExternal]
+fileName=${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGLF/pythia8/generator_pythia8_longlived_gaptriggered.C
+funcName=generateLongLivedGapTriggered("${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGLF/pythia8/generator/lnn_pbpb.gun", 1)
+
+[GeneratorPythia8]
+config=${O2_ROOT}/share/Generators/egconfig/pythia8_hi.cfg

MC/config/PWGLF/ini/tests/GeneratorLFLnnPbPb.C

@@ -0,0 +1,53 @@
+int External()
+{
+  std::string path{"o2sim_Kine.root"};
+  std::vector<int> possiblePDGs = {1010000030, -1010000030};
+
+  int nPossiblePDGs = possiblePDGs.size();
+
+  TFile file(path.c_str(), "READ");
+  if (file.IsZombie())
+  {
+    std::cerr << "Cannot open ROOT file " << path << "\n";
+    return 1;
+  }
+
+  auto tree = (TTree *)file.Get("o2sim");
+  if (!tree)
+  {
+    std::cerr << "Cannot find tree o2sim in file " << path << "\n";
+    return 1;
+  }
+  std::vector<o2::MCTrack> *tracks{};
+  tree->SetBranchAddress("MCTrack", &tracks);
+
+  std::vector<int> injectedPDGs;
+
+  auto nEvents = tree->GetEntries();
+  for (int i = 0; i < nEvents; i++)
+  {
+    auto check = tree->GetEntry(i);
+    for (int idxMCTrack = 0; idxMCTrack < tracks->size(); ++idxMCTrack)
+    {
+      auto track = tracks->at(idxMCTrack);
+      auto pdg = track.GetPdgCode();
+      auto it = std::find(possiblePDGs.begin(), possiblePDGs.end(), pdg);
+      if (it != possiblePDGs.end() && track.isPrimary())  // found
+      {
+        injectedPDGs.push_back(pdg);
+      }
+    }
+  }
+  std::cout << "--------------------------------\n";
+  std::cout << "# Events: " << nEvents << "\n";
+  if(injectedPDGs.empty()){
+    std::cerr << "No injected particles\n";
+    return 1; // At least one of the injected particles should be generated
+  }
+  for (int i = 0; i < nPossiblePDGs; i++)
+  {
+    std::cout << "# Injected nuclei \n";
+    std::cout << possiblePDGs[i] << ": " << std::count(injectedPDGs.begin(), injectedPDGs.end(), possiblePDGs[i]) << "\n";
+  }
+  return 0;
+}

MC/config/PWGLF/pythia8/generator/lnn_pbpb.gun

@@ -0,0 +1,3 @@
+# PDG           N      ptMin   ptMax   yMin   yMax
+1010000030      10     0.2     10      -1     1
+-1010000030     10     0.2     10      -1     1