[PWGEM] PhotonMeson: Add task for event normalization on derived data (#17875)

Co-authored-by: jokonig <jokonig@cern.ch>

Author: jokonig

PWGEM/PhotonMeson/Tasks/CMakeLists.txt

@@ -195,3 +195,8 @@ o2physics_add_dpl_workflow(emcal-mc-task
                     SOURCES emcalMcTask.cxx
                     PUBLIC_LINK_LIBRARIES O2::Framework O2Physics::AnalysisCore O2Physics::PWGEMPhotonMesonCore
                     COMPONENT_NAME Analysis)
+
+o2physics_add_dpl_workflow(event-normalization-task
+                    SOURCES eventNormalizationTask.cxx
+                    PUBLIC_LINK_LIBRARIES O2::Framework O2Physics::AnalysisCore
+                    COMPONENT_NAME Analysis)

PWGEM/PhotonMeson/Tasks/eventNormalizationTask.cxx

@@ -0,0 +1,85 @@
+// 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 eventNormalizationTask.cxx
+/// \brief task to produce histogram with event counter information
+/// \author Joshua Konig, joshua.konig@cern.ch
+
+#include "PWGEM/PhotonMeson/DataModel/EventTables.h"
+
+#include <Framework/AnalysisDataModel.h>
+#include <Framework/AnalysisTask.h>
+#include <Framework/Configurable.h>
+#include <Framework/HistogramRegistry.h>
+#include <Framework/HistogramSpec.h>
+#include <Framework/InitContext.h>
+#include <Framework/OutputObjHeader.h>
+#include <Framework/runDataProcessing.h>
+
+#include <TH1.h>
+
+#include <cstddef>
+#include <string>
+#include <vector>
+
+using namespace o2;
+using namespace o2::aod;
+using namespace o2::framework;
+using namespace o2::framework::expressions;
+using namespace o2::soa;
+
+struct EventNormalizationTask {
+
+  HistogramRegistry fRegistry{"output", {}, OutputObjHandlingPolicy::AnalysisObject, false, false};
+
+  void init(InitContext& /*context*/)
+  {
+    // Names derived from EventAcceptance bits in EventTables.h
+    std::vector<std::string> vecLabelNames = {
+      "all",
+      "has MC coll",
+      "good zVtx",
+      "is FT0AND",
+      "No TFB",
+      "ITS ROFB",
+      "Same bunch Pileup",
+      "ZVtxFT0PV",
+      "No coll in time range",
+      "good track occi",
+      "Good FT0 occupancy",
+      "kTVXinEMC",
+      "Good centrality",
+      "Good RCT",
+      "Good Sel8"};
+    fRegistry.add("EventNormalization/hEventCounter", "Event Counter;category;#it{N}_{evt}", kTH1D, {{static_cast<int>(vecLabelNames.size()), -0.5, -0.5 + static_cast<int>(vecLabelNames.size())}}, false);
+    for (size_t i = 0; i < vecLabelNames.size(); ++i) {
+      fRegistry.get<TH1>(HIST("EventNormalization/hEventCounter"))->GetXaxis()->SetBinLabel(i + 1, vecLabelNames[i].c_str());
+    }
+  }
+
+  // Process function only takes the entries and fills them into the histogram. This is done per DF and not per collision
+  void processNorm(o2::aod::PMEvSelBit const& evSelBit)
+  {
+
+    auto vecEvSelBits = evSelBit.eventSelectionBit();
+    for (size_t i = 0; i < vecEvSelBits.size(); ++i) {
+      fRegistry.fill(HIST("EventNormalization/hEventCounter"), i, vecEvSelBits[i]);
+    }
+  }
+
+  PROCESS_SWITCH(EventNormalizationTask, processNorm, "run event normalization task", true);
+};
+
+WorkflowSpec defineDataProcessing(ConfigContext const& context)
+{
+  return WorkflowSpec{
+    adaptAnalysisTask<EventNormalizationTask>(context, TaskName{"event-normalization-task"})};
+}