centrality properly stored in mc and added to output table

Author: GiorgioAlbertoLucia

PWGLF/DataModel/LFSlimNucleiTables.h

@@ -201,6 +201,7 @@ DECLARE_SOA_TABLE(NucleiTableRed, "AOD", "NUCLEITABLERED",
                   NucleiTableNS::DCAxy,
                   NucleiTableNS::DCAz,
                   NucleiTableNS::Flags,
+                  NucleiFlowTableNS::CentFT0C,
                   NucleiTableNS::gPt,
                   NucleiTableNS::McProcess,
                   NucleiTableNS::PDGcode,

PWGLF/TableProducer/QC/nucleiQC.cxx

@@ -517,6 +517,7 @@ struct nucleiQC {
       candidate.DCAxy,
       candidate.DCAz,
       candidate.flags,
+      candidate.centrality,
       candidate.ptGenerated,
       candidate.mcProcess,
       candidate.pdgCode,
@@ -531,6 +532,7 @@ struct nucleiQC {
     gRandom->SetSeed(67);
     std::unordered_set<int> reconstructedMcParticles;
     std::unordered_set<int> reconstructedCollisions;
+    std::map<int, float> mcCollisionIdToCentrality;
 
     for (const auto& collision : collisions) {
 
@@ -539,8 +541,10 @@ struct nucleiQC {
 
       if (!nuclei::eventSelection(collision, mHistograms, cfgEventSelections, cfgCutVertex))
         continue;
-      mHistograms.fill(HIST("hCentrality"), nuclei::getCentrality(collision, cfgCentralityEstimator, mHistFailCentrality));
+      const float centrality = nuclei::getCentrality(collision, cfgCentralityEstimator, mHistFailCentrality);
+      mHistograms.fill(HIST("hCentrality"), centrality);
       reconstructedCollisions.insert(collision.mcCollisionId());
+      mcCollisionIdToCentrality[collision.mcCollisionId()] = centrality;
       mVtx.setPos({collision.posX(), collision.posY(), collision.posZ()});
       mVtx.setCov(collision.covXX(), collision.covXY(), collision.covYY(), collision.covXZ(), collision.covYZ(), collision.covZZ());
 
@@ -635,8 +639,8 @@ struct nucleiQC {
       }
 
       nuclei::SlimCandidate candidate;
-      // candidate.centrality = nuclei::getCentrality(collision, cfgCentralityEstimator, mHistFailCentrality);
-      candidate.centrality = -1.f; // centrality is not well defined for non-reconstructed particles, set to -1 for now
+      const auto& centralityIt = mcCollisionIdToCentrality.find(particle.mcCollisionId());
+      candidate.centrality = centralityIt != mcCollisionIdToCentrality.end() ? centralityIt->second : -1.f;
       fillCollisionFlag(particle, candidate, reconstructedCollisions);
       fillNucleusFlagsPdgsMc(particle, candidate);
       fillNucleusGeneratedVariables(particle, candidate);