Add LF generator for MC with coalescence production for De Tr He3

MC/config/PWGLF/ini/GeneratorLF_Coalescence_pp536TeV.ini

@@ -0,0 +1,7 @@
+[GeneratorExternal]
+fileName = ${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGLF/pythia8/generator_pythia8_coalescence.C
+funcName = generateCoalescence({1000010020, 1000010030, 1000020030}, 1, 0.239)
+
+[GeneratorPythia8]
+config=${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGLF/pythia8/generator/pythia8_inel_pp536tev.cfg
+

MC/config/PWGLF/ini/tests/GeneratorLF_Coalescence_pp536TeV.C

@@ -0,0 +1,28 @@
+int External()
+{
+    std::string path{"o2sim_Kine.root"};
+
+    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);
+
+    auto nEvents = tree->GetEntries();
+    if (nEvents < 1)
+    {
+        std::cerr << "No events actually generated: not OK!";
+        return 1;
+    }
+    return 0;
+}

MC/config/PWGLF/pythia8/generator/pythia8_inel_pp536tev.cfg

@@ -0,0 +1,18 @@
+### beams
+Beams:idA = 2212   # proton
+Beams:idB = 2212   # proton
+Beams:eCM = 5360. # GeV
+
+### processes
+SoftQCD:inelastic = on # all inelastic processes
+
+### decays
+ParticleDecays:limitTau0 = on
+ParticleDecays:tau0Max = 10.
+
+### phase space cuts
+PhaseSpace:pTHatMin = 0.000000
+PhaseSpace:pTHatMax = -1.000000
+
+Random:setSeed = on
+Random:seed = 0