[PWGEM] Add task for model predictions for meson spectra from OTF sims (#12558)

Author: hscheid

PWGEM/Dilepton/Tasks/CMakeLists.txt

@@ -161,3 +161,7 @@ o2physics_add_dpl_workflow(dimuon-hadron-mpc
                     PUBLIC_LINK_LIBRARIES O2::Framework O2::DetectorsBase O2Physics::AnalysisCore O2Physics::MLCore O2Physics::PWGEMDileptonCore
                     COMPONENT_NAME Analysis)
 
+o2physics_add_dpl_workflow(mc-particle-predictions-otf
+                    SOURCES mcParticlePredictionsOTF.cxx
+                    PUBLIC_LINK_LIBRARIES O2::Framework O2Physics::AnalysisCore
+                    COMPONENT_NAME Analysis)

PWGEM/Dilepton/Tasks/mcParticlePredictionsOTF.cxx

@@ -0,0 +1,98 @@
+// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
+// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
+// All rights not expressly granted are reserved.
+//
+// This software is distributed under the terms of the GNU General Public
+// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+///
+/// \file   mcParticlePrediction.cxx
+/// \author Sebastian Scheid, s.scheid@cern.ch
+/// \brief Task to build the predictions from the models based on the generated particles
+///
+
+#include "Framework/AnalysisTask.h"
+#include "Framework/HistogramRegistry.h"
+#include "Framework/runDataProcessing.h"
+
+using namespace o2;
+using namespace o2::framework;
+
+struct otfParticlePrediction {
+  // histogram registry
+  HistogramRegistry histos{"Histos", {}, OutputObjHandlingPolicy::AnalysisObject};
+  // define configurables
+  ConfigurableAxis binsEta{"binsEta", {100, -5, 5}, "Binning of the Eta axis"};
+  ConfigurableAxis binsPt{"binsPt", {100, 0, 10}, "Binning of the Pt axis"};
+
+  Configurable<float> maxEtaParticle{"maxEtaParticle", 5.f, "Max eta of particles considered"};
+
+  // init function
+  void
+    init()
+  {
+
+    const AxisSpec axisEta{binsEta, "#eta"};
+    const AxisSpec axisPt{binsPt, "#it{p}_{T} (GeV/#it{c})"};
+
+    histos.add<TH1>("collisions/generated", "collisions", kTH1D, {{2, -0.5, 1.5}});
+    histos.add<TH2>("particles/generated/pi0", "pi0", kTH2D, {axisPt, axisEta});
+    histos.add<TH2>("particles/generated/eta", "eta", kTH2D, {axisPt, axisEta});
+    histos.add<TH2>("particles/generated/etaP", "etaP", kTH2D, {axisPt, axisEta});
+    histos.add<TH2>("particles/generated/rho", "rho", kTH2D, {axisPt, axisEta});
+    histos.add<TH2>("particles/generated/omega", "omega", kTH2D, {axisPt, axisEta});
+    histos.add<TH2>("particles/generated/phi", "phi", kTH2D, {axisPt, axisEta});
+  }
+
+  void process(aod::McCollisions const& mcCollisions,
+               aod::McParticles const& mcParticles)
+  {
+
+    histos.fill(HIST("collisions/generated"), 0, mcCollisions.size());
+
+    for (const auto& particle : mcParticles) {
+      auto pdg = std::abs(particle.pdgCode());
+      if (particle.eta() < maxEtaParticle) {
+        continue;
+      }
+      if (pdg < 100) {
+        continue;
+      }
+      if (pdg > 1000) {
+        continue;
+      }
+      switch (pdg) {
+        case 111:
+          histos.fill(HIST("particles/generated/pi0"), particle.pt(), particle.eta());
+          break;
+        case 221:
+          histos.fill(HIST("particles/generated/eta"), particle.pt(), particle.eta());
+          break;
+        case 331:
+          histos.fill(HIST("particles/generated/etaP"), particle.pt(), particle.eta());
+          break;
+        case 223:
+          histos.fill(HIST("particles/generated/omega"), particle.pt(), particle.eta());
+          break;
+        case 113:
+          histos.fill(HIST("particles/generated/rho"), particle.pt(), particle.eta());
+          break;
+        case 333:
+          histos.fill(HIST("particles/generated/phi"), particle.pt(), particle.eta());
+          break;
+        default:
+          break;
+      }
+    }
+  }
+};
+
+WorkflowSpec
+  defineDataProcessing(ConfigContext const& cfgc)
+{
+  return WorkflowSpec{adaptAnalysisTask<otfParticlePrediction>(cfgc)};
+}