Merge pull request #19986 from dildick/from-CMSSW_9_3_X_2017-07-31-23…

…00-gem-me0-clustersize-maxclusters

Restrict GEM/ME0 cluster size and max N clusters

SimMuon/GEMDigitizer/src/GEMPadDigiClusterProducer.cc

@@ -53,10 +53,15 @@ void GEMPadDigiClusterProducer::produce(edm::Event& e, const edm::EventSetup& ev
 }
 
 
-void GEMPadDigiClusterProducer::buildClusters(const GEMPadDigiCollection &det_pads, GEMPadDigiClusterCollection &out_clusters)
+void GEMPadDigiClusterProducer::buildClusters(const GEMPadDigiCollection &det_pads,
+                                              GEMPadDigiClusterCollection &out_clusters)
 {
+  // construct clusters
   for (const auto& ch: geometry_->chambers()) {
-    unsigned int nClusters = 0;
+
+    // proto collection
+    std::vector<std::pair<GEMDetId, GEMPadDigiCluster> > proto_clusters;
+
     for (const auto& part: ch->etaPartitions()) {
       auto pads = det_pads.get(part->id());
       std::vector<uint16_t> cl;
@@ -66,24 +71,36 @@ void GEMPadDigiClusterProducer::buildClusters(const GEMPadDigiCollection &det_pa
           cl.push_back((*d).pad());
         }
         else {
-          if ((*d).bx() == startBX and (*d).pad() == cl.back() + 1) {
+          if ((*d).bx() == startBX and // same bunch crossing
+              (*d).pad() == cl.back() + 1 // pad difference is 1
+              and cl.size()<maxClusterSize_) { // max 8 in cluster
             cl.push_back((*d).pad());
           }
           else {
+            // put the current cluster in the proto collection
             GEMPadDigiCluster pad_cluster(cl, startBX);
-            out_clusters.insertDigi(part->id(), pad_cluster);
+            proto_clusters.emplace_back(part->id(), pad_cluster);
+
+            // start a new cluster
             cl.clear();
             cl.push_back((*d).pad());
-            nClusters++;
           }
         }
         startBX = (*d).bx();
       }
+      // put the last cluster in the proto collection
       if (pads.first != pads.second){
         GEMPadDigiCluster pad_cluster(cl, startBX);
-        out_clusters.insertDigi(part->id(), pad_cluster);
-        nClusters++;
+        proto_clusters.emplace_back(part->id(), pad_cluster);
       }
+    } // end of partition loop
+
+    // cluster selection: pick first maxClusters_ for now
+    unsigned loopMax=std::min(maxClusters_,unsigned(proto_clusters.size()));
+    for ( unsigned int i=0; i<loopMax; i++) {
+      const auto& detid(proto_clusters[i].first);
+      const auto& cluster(proto_clusters[i].second);
+      out_clusters.insertDigi(detid, cluster);
     }
-  }
+  } // end of chamber loop
 }

SimMuon/GEMDigitizer/src/GEMPadDigiProducer.cc

@@ -52,24 +52,23 @@ void GEMPadDigiProducer::produce(edm::Event& e, const edm::EventSetup& eventSetu
 
 void GEMPadDigiProducer::buildPads(const GEMDigiCollection &det_digis, GEMPadDigiCollection &out_pads) const
 {
-  auto etaPartitions = geometry_->etaPartitions();
-  for(const auto& p: etaPartitions)
+  for(const auto& p: geometry_->etaPartitions())
   {
     // set of <pad, bx> pairs, sorted first by pad then by bx
     std::set<std::pair<int, int> > proto_pads;
-  
-    // walk over digis in this partition, 
+
+    // walk over digis in this partition,
     // and stuff them into a set of unique pads (equivalent of OR operation)
     auto digis = det_digis.get(p->id());
     for (auto d = digis.first; d != digis.second; ++d)
     {
       int pad_num = 1 + static_cast<int>( p->padOfStrip(d->strip()) );
       proto_pads.emplace(pad_num, d->bx());
     }
-  
+
     // in the future, do some dead-time handling
     // emulateDeadTime(proto_pads)
-  
+
     // fill the output collections
     for (const auto& d: proto_pads)
     {

SimMuon/GEMDigitizer/src/ME0PadDigiClusterProducer.cc

@@ -53,9 +53,15 @@ void ME0PadDigiClusterProducer::produce(edm::Event& e, const edm::EventSetup& ev
 }
 
 
-void ME0PadDigiClusterProducer::buildClusters(const ME0PadDigiCollection &det_pads, ME0PadDigiClusterCollection &out_clusters)
+void ME0PadDigiClusterProducer::buildClusters(const ME0PadDigiCollection &det_pads,
+                                              ME0PadDigiClusterCollection &out_clusters)
 {
-  for (const auto& ch: geometry_->chambers()) {
+  // construct clusters
+  for (const auto& ch: geometry_->layers()) {
+
+    // proto collection
+    std::vector<std::pair<ME0DetId, ME0PadDigiCluster> > proto_clusters;
+
     for (const auto& part: ch->etaPartitions()) {
       auto pads = det_pads.get(part->id());
       std::vector<uint16_t> cl;
@@ -65,22 +71,36 @@ void ME0PadDigiClusterProducer::buildClusters(const ME0PadDigiCollection &det_pa
           cl.push_back((*d).pad());
         }
         else {
-          if ((*d).bx() == startBX and (*d).pad() == cl.back() + 1) {
+          if ((*d).bx() == startBX and // same bunch crossing
+              (*d).pad() == cl.back() + 1 // pad difference is 1
+              and cl.size()<maxClusterSize_) { // max 8 in cluster
             cl.push_back((*d).pad());
           }
           else {
+            // put the current cluster in the proto collection
             ME0PadDigiCluster pad_cluster(cl, startBX);
-            out_clusters.insertDigi(part->id(), pad_cluster);
+            proto_clusters.emplace_back(part->id(), pad_cluster);
+
+            // start a new cluster
             cl.clear();
             cl.push_back((*d).pad());
           }
         }
         startBX = (*d).bx();
       }
+      // put the last cluster in the proto collection
       if (pads.first != pads.second){
         ME0PadDigiCluster pad_cluster(cl, startBX);
-        out_clusters.insertDigi(part->id(), pad_cluster);
+        proto_clusters.emplace_back(part->id(), pad_cluster);
       }
+    } // end of partition loop
+
+    // cluster selection: pick first maxClusters_ for now
+    unsigned loopMax=std::min(maxClusters_,unsigned(proto_clusters.size()));
+    for ( unsigned int i=0; i<loopMax; i++) {
+      const auto& detid(proto_clusters[i].first);
+      const auto& cluster(proto_clusters[i].second);
+      out_clusters.insertDigi(detid, cluster);
     }
-  }
+  } // end of chamber loop
 }

SimMuon/GEMDigitizer/src/ME0PadDigiProducer.cc

@@ -51,8 +51,7 @@ void ME0PadDigiProducer::produce(edm::Event& e, const edm::EventSetup& eventSetu
 
 void ME0PadDigiProducer::buildPads(const ME0DigiCollection &det_digis, ME0PadDigiCollection &out_pads) const
 {
-  auto etaPartitions = geometry_->etaPartitions();
-  for(const auto& p: etaPartitions)
+  for(const auto& p: geometry_->etaPartitions())
   {
     // set of <pad, bx> pairs, sorted first by pad then by bx
     std::set<std::pair<int, int> > proto_pads;