ITS: suppress low mult 2nd vertices

Signed-off-by: Felix Schlepper <felix.schlepper@cern.ch>

Author: f3sch

Detectors/ITSMFT/ITS/tracking/include/ITStracking/Configuration.h

@@ -104,12 +104,13 @@ struct VertexingParameters {
   float vertRadiusSigma = -1.f;
   float trackletSigma = -1.f;
   float maxZPositionAllowed = -1.f;
-  int clusterContributorsCut = -1.f;
-  int seedMemberRadiusTime = -1.f;
-  int seedMemberRadiusZ = -1.f;
-  int maxTrackletsPerCluster = -1.f;
-  int phiSpan = -1.f;
-  int zSpan = -1.f;
+  int clusterContributorsCut = -1;
+  int suppressLowMultDebris = -1;
+  int seedMemberRadiusTime = -1;
+  int seedMemberRadiusZ = -1;
+  int maxTrackletsPerCluster = -1;
+  int phiSpan = -1;
+  int zSpan = -1;
   bool SaveTimeBenchmarks = false;
 
   bool useTruthSeeding = false; // overwrite found vertices with MC events

Detectors/ITSMFT/ITS/tracking/include/ITStracking/LineVertexerHelpers.h

@@ -36,7 +36,6 @@ struct Settings {
   float maxZ = 0.f;
   int seedMemberRadiusTime = 1;
   int seedMemberRadiusZ = 2;
-  int clusterContributorsCut = 3;
   std::shared_ptr<BoundedMemoryResource> memoryPool;
 };
 

Detectors/ITSMFT/ITS/tracking/include/ITStracking/TrackingConfigParam.h

@@ -40,10 +40,11 @@ struct VertexerParamConfig : public o2::conf::ConfigurableParamHelper<VertexerPa
   float vertNsigmaCut = 5.8762583f;   // N sigma cut for vertex XY
   float vertRadiusSigma = 0.0343575f; // sigma of vertex XY
   float trackletSigma = 0.0143798f;   // tracklet to vertex sigma
-  float maxZPositionAllowed = 25.f; // 4x sZ of the beam
+  float maxZPositionAllowed = 25.f;   // 4x sZ of the beam
 
   // Artefacts selections
   int clusterContributorsCut = 3; // minimum number of contributors for an accepted final vertex
+  int suppressLowMultDebris = 16; // suppress all vertices below this threshold if a vertex was already found in a rof
   int seedMemberRadiusTime = 0;
   int seedMemberRadiusZ = 2;
   int maxTrackletsPerCluster = 100;

Detectors/ITSMFT/ITS/tracking/src/Configuration.cxx

@@ -57,8 +57,8 @@ std::string TrackingParameters::asString() const
 
 std::string VertexingParameters::asString() const
 {
-  std::string str = std::format("NZb:{} NPhB:{} MinVtxCont:{} MaxTrkltCls:{} ZCut:{} PhCut:{} PairCut:{} ClCut:{} SeedRad:{}x{}",
-                                ZBins, PhiBins, clusterContributorsCut, maxTrackletsPerCluster, zCut, phiCut, pairCut, clusterCut, seedMemberRadiusTime, seedMemberRadiusZ);
+  std::string str = std::format("NZb:{} NPhB:{} MinVtxCont:{} SupLowMultDebris:{} MaxTrkltCls:{} ZCut:{} PhCut:{} PairCut:{} ClCut:{} SeedRad:{}x{}",
+                                ZBins, PhiBins, clusterContributorsCut, suppressLowMultDebris, maxTrackletsPerCluster, zCut, phiCut, pairCut, clusterCut, seedMemberRadiusTime, seedMemberRadiusZ);
   if (std::numeric_limits<size_t>::max() != MaxMemory) {
     str += std::format(" MemLimit {:.2f} GB", double(MaxMemory) / constants::GB);
   }
@@ -263,6 +263,7 @@ std::vector<VertexingParameters> TrackingMode::getVertexingParameters(TrackingMo
     p.trackletSigma = vc.trackletSigma;
     p.maxZPositionAllowed = vc.maxZPositionAllowed;
     p.clusterContributorsCut = vc.clusterContributorsCut;
+    p.suppressLowMultDebris = vc.suppressLowMultDebris;
     p.seedMemberRadiusTime = vc.seedMemberRadiusTime;
     p.seedMemberRadiusZ = vc.seedMemberRadiusZ;
     p.phiSpan = vc.phiSpan;

Detectors/ITSMFT/ITS/tracking/src/VertexerTraits.cxx

@@ -349,7 +349,6 @@ void VertexerTraits<NLayers>::computeVertices(const int iteration)
   settings.maxZ = mVrtParams[iteration].maxZPositionAllowed;
   settings.seedMemberRadiusTime = mVrtParams[iteration].seedMemberRadiusTime;
   settings.seedMemberRadiusZ = mVrtParams[iteration].seedMemberRadiusZ;
-  settings.clusterContributorsCut = mVrtParams[iteration].clusterContributorsCut;
   settings.memoryPool = mMemoryPool;
 
   const auto processROF = [&](const int rofId) {
@@ -500,28 +499,38 @@ void VertexerTraits<NLayers>::computeVertices(const int iteration)
       selectedIndices.push_back(clusterId);
     }
 
-    for (const auto clusterId : selectedIndices) {
-      const auto beamDistance2 = clusterBeamDistance2(clusters[clusterId]);
+    // sort vertices by their multiplicity to opt. suppress lower mult. debris
+    std::vector<int> sortedIndices(selectedIndices.size());
+    std::iota(sortedIndices.begin(), sortedIndices.end(), 0);
+    std::sort(sortedIndices.begin(), sortedIndices.end(), [&selectedIndices, &clusters](int i, int j) {
+      return clusters[selectedIndices[i]].getSize() > clusters[selectedIndices[j]].getSize();
+    });
+    for (const auto sortedId : sortedIndices) {
+      const auto& cluster = clusters[selectedIndices[sortedId]];
+      const auto beamDistance2 = clusterBeamDistance2(cluster);
       if (!(beamDistance2 < nsigmaCut)) {
         continue;
       }
-      if (clusters[clusterId].getSize() < settings.clusterContributorsCut) {
+      if (cluster.getSize() < mVrtParams[iteration].clusterContributorsCut) {
+        continue;
+      }
+      if (!rofVertices[rofId].empty() && cluster.getSize() < mVrtParams[iteration].suppressLowMultDebris) {
         continue;
       }
 
-      Vertex vertex{clusters[clusterId].getVertex().data(),
-                    clusters[clusterId].getRMS2(),
-                    (ushort)clusters[clusterId].getSize(),
-                    clusters[clusterId].getAvgDistance2()};
+      Vertex vertex{cluster.getVertex().data(),
+                    cluster.getRMS2(),
+                    (ushort)cluster.getSize(),
+                    cluster.getAvgDistance2()};
       if (iteration) {
         vertex.setFlags(Vertex::UPCMode);
       }
-      vertex.setTimeStamp(clusters[clusterId].getTimeStamp());
+      vertex.setTimeStamp(cluster.getTimeStamp());
       rofVertices[rofId].push_back(vertex);
       if (mTimeFrame->hasMCinformation()) {
         auto& lineLabels = mTimeFrame->getLinesLabel(rofId);
         bounded_vector<o2::MCCompLabel> labels(mMemoryPool.get());
-        for (auto& index : clusters[clusterId].getLabels()) {
+        for (auto& index : cluster.getLabels()) {
           labels.push_back(lineLabels[index]);
         }
         const auto mainLabel = computeMain(labels);

prodtests/full-system-test/dpl-workflow.sh

@@ -119,7 +119,7 @@ EVE_OPT=" --jsons-folder $EDJSONS_DIR"
 
 # ITS vertexing settings
 if [[ $BEAMTYPE == "pp" || $LIGHTNUCLEI == "1" ]]; then
-  ITS_CONFIG_KEY+=";ITSVertexerParam.pairCut=0.0317563;ITSVertexerParam.clusterCut=0.6640964;ITSVertexerParam.coarseZWindow=0.2049018;ITSVertexerParam.seedDedupZCut=0.0711793;ITSVertexerParam.refitDedupZCut=0.0680009;ITSVertexerParam.duplicateZCut=0.1582193;ITSVertexerParam.finalSelectionZCut=0.1081465;ITSVertexerParam.duplicateDistance2Cut=0.0117033;ITSVertexerParam.clusterContributorsCut=2;ITSVertexerParam.seedMemberRadiusZ=0;ITSVertexerParam.vertNsigmaCut=4.0;ITSVertexerParam.vertRadiusSigma=0.0452309;ITSVertexerParam.trackletSigma=0.0025941;"
+  ITS_CONFIG_KEY+=";ITSVertexerParam.pairCut=0.0317563;ITSVertexerParam.clusterCut=0.6640964;ITSVertexerParam.coarseZWindow=0.2049018;ITSVertexerParam.seedDedupZCut=0.0711793;ITSVertexerParam.refitDedupZCut=0.0680009;ITSVertexerParam.duplicateZCut=0.1582193;ITSVertexerParam.finalSelectionZCut=0.1081465;ITSVertexerParam.duplicateDistance2Cut=0.0117033;ITSVertexerParam.clusterContributorsCut=2;ITSVertexerParam.seedMemberRadiusZ=0;ITSVertexerParam.vertNsigmaCut=4.0;ITSVertexerParam.vertRadiusSigma=0.0452309;ITSVertexerParam.trackletSigma=0.0025941;ITSVertexerParam.suppressLowMultDebris=0;"
 fi
 
 if [[ $CTFINPUT != 1 ]]; then