[DPG] Update detectorOccupancyQa.cxx - fix PID column bug on the fly (#10683)

Author: altsybee

DPG/Tasks/AOTEvent/detectorOccupancyQa.cxx

@@ -191,6 +191,19 @@ struct DetectorOccupancyQaTask {
       histos.add("fraction_tpcNClsFindableMinusPID_vs_occup_lowPt", "", kTH2D, {axisOccupancyForDeDxStudies, axisFractionNclsFindableMinusPID});
       histos.add("fraction_tpcNClsFindableMinusPID_vs_occup_highPt", "", kTH2D, {axisOccupancyForDeDxStudies, axisFractionNclsFindableMinusPID});
 
+      // more QA for TPC cls counting
+      histos.add("tpcNClsFindable", "", kTH1D, {{601, -300.5, 300.5}});
+      histos.add("tpcNClsFindableMinusFound", "", kTH1D, {{601, -300.5, 300.5}});
+      histos.add("tpcNClsFindableMinusCrossedRows", "", kTH1D, {{601, -300.5, 300.5}});
+      histos.add("tpcNClsShared", "", kTH1D, {{601, -300.5, 300.5}});
+      histos.add("tpcNClsFindableMinusPID", "", kTH1D, {{601, -300.5, 300.5}});
+      histos.add("tpcNClsFindableMinusPID_CORRECTED", "", kTH1D, {{601, -300.5, 300.5}});
+      histos.add("tpcNClUsedForPID", "", kTH1D, {{601, -300.5, 300.5}});
+
+      histos.add("tpcNClsUsedForPID_vs_Findable", ";tpcNClsFindable;tpcNClUsedForPID", kTH2D, {{601, -300.5, 300.5}, {601, -300.5, 300.5}});
+      histos.add("tpcNClsShared_vs_Findable", ";tpcNClsFindable;tpcNClsShared", kTH2D, {{601, -300.5, 300.5}, {601, -300.5, 300.5}});
+      histos.add("tpcNClsUsedForPID_vs_Shared", ";tpcNClsShared;tpcNClUsedForPID", kTH2D, {{601, -300.5, 300.5}, {601, -300.5, 300.5}});
+
       // ### kinematic distributions for events with high occupancy at specified dt ranges
       histos.add("track_distr_nITStrThisEv_10_200/hEventCount", ";delta-time bin id;n events", kTH1D, {{5, -0.5, 4.5}});
       histos.add("track_distr_nITStrThisEv_above_2000/hEventCount", ";delta-time bin id;n events", kTH1D, {{5, -0.5, 4.5}});
@@ -895,9 +908,29 @@ struct DetectorOccupancyQaTask {
                 if (track.eta() > -0.4 && track.eta() < -0.2)
                   histos.fill(HIST("dEdx_vs_Momentum_vs_occup_eta_04_02"), signedP, track.tpcSignal(), occupancy);
               }
-
-              // check ratio tpcNClsFindableMinusPID / tpcNClsFindable (https://github.com/AliceO2Group/AliceO2/blob/dev/Framework/Core/include/Framework/AnalysisDataModel.h#L242)
-              float fractionTPCcls = (1.0 * track.tpcNClsFindableMinusPID()) / track.tpcNClsFindable();
+              // more QA for TPC cls counting
+              histos.fill(HIST("tpcNClsFindable"), track.tpcNClsFindable());
+              histos.fill(HIST("tpcNClsFindableMinusFound"), track.tpcNClsFindableMinusFound());
+              histos.fill(HIST("tpcNClsFindableMinusCrossedRows"), track.tpcNClsFindableMinusCrossedRows());
+              histos.fill(HIST("tpcNClsShared"), track.tpcNClsShared());
+              histos.fill(HIST("tpcNClsFindableMinusPID"), track.tpcNClsFindableMinusPID());
+              int tpcNClUsedForPID = track.tpcNClsFindable() - track.tpcNClsFindableMinusPID();
+              histos.fill(HIST("tpcNClUsedForPID"), tpcNClUsedForPID);
+
+              histos.fill(HIST("tpcNClsUsedForPID_vs_Findable"), track.tpcNClsFindable(), tpcNClUsedForPID);
+              histos.fill(HIST("tpcNClsShared_vs_Findable"), track.tpcNClsFindable(), track.tpcNClsShared());
+              histos.fill(HIST("tpcNClsUsedForPID_vs_Shared"), tpcNClUsedForPID, track.tpcNClsShared());
+
+              int tpcNClsCorrectedFindableMinusPID = track.tpcNClsFindableMinusPID();
+              // correct for a buggy behaviour due to int8 and uint8 difference:
+              if (tpcNClsCorrectedFindableMinusPID < -70)
+                tpcNClsCorrectedFindableMinusPID += 256;
+              histos.fill(HIST("tpcNClsFindableMinusPID_CORRECTED"), tpcNClsCorrectedFindableMinusPID);
+
+              // check ratio tpcNClsFindableMinusPID / tpcNClsFindable
+              // https://github.com/AliceO2Group/AliceO2/blob/dev/Framework/Core/include/Framework/AnalysisDataModel.h#L242)
+              // https://github.com/AliceO2Group/AliceO2/blob/dev/Detectors/AOD/src/AODProducerWorkflowSpec.cxx#L2553C21-L2553C44
+              float fractionTPCcls = (1.0 * tpcNClsCorrectedFindableMinusPID) / track.tpcNClsFindable();
               histos.fill(HIST("fraction_tpcNClsFindableMinusPID_vs_occup"), occupancy, fractionTPCcls);
               if (fractionTPCcls >= 0 && fractionTPCcls < 0.8)
                 histos.fill(HIST("nTrackCounter_after_cuts_QA"), 8);