TRD Clusterizer Hotfix

This MR fixes the problem in the TRD clusterizer that occurs when two selftriggered digis are on neighbored addresschannels but inbetween is a change in the padrow. Previously these digis were added to the same cluster, with this fix this should not happen anymore.

Also the IsClusterComplete function is hardened against incorrect cluster sizes reported by CbmTrdCluster::GetNCols() and CbmTrdCluster::GetNRows(), which were reported for the incorrectly built clusters described above and led to crashes in reconstruction of mCBM2024 data.

reco/detectors/trd/CbmTrdModuleRecR.cxx

@@ -199,6 +199,14 @@ Int_t CbmTrdModuleRecR::FindClusters(bool)
     //    triggerId<<"  ncols: " << ncols<<std::endl;
     std::get<1>(*mainit) = true;
 
+    // already seal the cluster if the main trigger is already at the right or left padrow border
+    if (channel % ncols == ncols - 1) {
+      sealtopcol = true;
+    }
+    if (channel % ncols == 0) {
+      sealbotcol = true;
+    }
+
     //      Bool_t mergerow=CbmTrdClusterFinder::HasRowMerger();
     Bool_t mergerow = true;
     // loop to find the other pads corresponding to the main trigger
@@ -240,12 +248,12 @@ Int_t CbmTrdModuleRecR::FindClusters(bool)
             counterbot++;
             std::get<0>(botdigi) = d;
           }
-          if (ch == (channel - ncols) - 1 && rowchange && !std::get<1>(*FNit)) {
+          if (ch == (channel - ncols) - 1 && rowchange && !std::get<1>(*FNit) && !sealbotcol) {
             bufferbot[1] = charge;
             counterbot++;
             std::get<1>(botdigi) = d;
           }
-          if (ch == (channel - ncols) + 1 && rowchange && !std::get<1>(*FNit)) {
+          if (ch == (channel - ncols) + 1 && rowchange && !std::get<1>(*FNit) && !sealtopcol) {
             bufferbot[2] = charge;
             counterbot++;
             std::get<2>(botdigi) = d;
@@ -257,23 +265,23 @@ Int_t CbmTrdModuleRecR::FindClusters(bool)
             countertop++;
             std::get<0>(topdigi) = d;
           }
-          if (ch == (channel + ncols) - 1 && rowchange && !std::get<1>(*FNit)) {
+          if (ch == (channel + ncols) - 1 && rowchange && !std::get<1>(*FNit) && !sealbotcol) {
             buffertop[1] = charge;
             countertop++;
             std::get<1>(topdigi) = d;
           }
-          if (ch == (channel + ncols) + 1 && rowchange && !std::get<1>(*FNit)) {
+          if (ch == (channel + ncols) + 1 && rowchange && !std::get<1>(*FNit) && !sealtopcol) {
             buffertop[2] = charge;
             countertop++;
             std::get<2>(topdigi) = d;
           }
 
-          if (ch == channel - 1) {
+          if (ch == channel - 1 && !sealbotcol) {
             bufferrow[1] = charge;
             counterrow++;
             std::get<1>(topdigi) = d;
           }
-          if (ch == channel + 1) {
+          if (ch == channel + 1 && !sealtopcol) {
             bufferrow[2] = charge;
             counterrow++;
             std::get<2>(topdigi) = d;
@@ -294,7 +302,7 @@ Int_t CbmTrdModuleRecR::FindClusters(bool)
 
         // logical implementation of the trigger logic in the same row as the
         // main trigger
-        if (ch == lowcol - 1 && triggertype == CbmTrdDigi::eTriggerType::kSelf && !std::get<1>(*FNit)) {
+        if (ch == lowcol - 1 && triggertype == CbmTrdDigi::eTriggerType::kSelf && !std::get<1>(*FNit) && !sealbotcol) {
           cluster.push_back(std::make_pair(digiid, d));
           lowcol = ch;
           dmain++;
@@ -303,7 +311,7 @@ Int_t CbmTrdModuleRecR::FindClusters(bool)
             std::cout << " time: " << newtime << " charge: " << charge << "   col: " << col << "   row: " << ch / ncols
                       << "   trigger: " << trigger << std::endl;
         }
-        if (ch == highcol + 1 && triggertype == CbmTrdDigi::eTriggerType::kSelf && !std::get<1>(*FNit)) {
+        if (ch == highcol + 1 && triggertype == CbmTrdDigi::eTriggerType::kSelf && !std::get<1>(*FNit) && !sealtopcol) {
           cluster.push_back(std::make_pair(digiid, d));
           highcol = ch;
           dmain++;
@@ -332,7 +340,9 @@ Int_t CbmTrdModuleRecR::FindClusters(bool)
             std::cout << " time: " << newtime << " charge: " << charge << "   col: " << col << "   row: " << ch / ncols
                       << "   trigger: " << trigger << std::endl;
         }
-        if (col == ncols) { sealtopcol = true; }
+        if (col == ncols - 1) {
+          sealtopcol = true;
+        }
         if (col == 0) { sealbotcol = true; }
 
         if (mergerow) {
@@ -351,19 +361,27 @@ Int_t CbmTrdModuleRecR::FindClusters(bool)
             dmain++;
             std::get<1>(*FNit) = true;
           }
+          /* apuntke, Mar 19 2024: I think it is possible that simultaneously the above and below rows get added in
+          this code and this is not taken into account in the following 4 blocks, since the two variables indicating
+          if the cluster is sealed on the sides in the added row (sealtoprow & sealbotrow) are simultaneously used
+          for both cases (top row merged (addtop==true) and bottom row merged (addbot==true)).
+          This needs to be investigated further.
+          */
           if (rowchange && ch == lowrow - 1 && lowrow != channel && triggertype == CbmTrdDigi::eTriggerType::kSelf
-              && !std::get<1>(*FNit)) {
+              && !std::get<1>(*FNit) && !sealbotrow) {
             cluster.push_back(std::make_pair(digiid, d));
             lowrow = ch;
             dmain++;
             std::get<1>(*FNit) = true;
+            if (lowrow % ncols == 0) sealbotrow = true;
           }
           if (rowchange && ch == highrow + 1 && highrow != channel && triggertype == CbmTrdDigi::eTriggerType::kSelf
-              && !std::get<1>(*FNit)) {
+              && !std::get<1>(*FNit) && !sealtoprow) {
             cluster.push_back(std::make_pair(digiid, d));
             highrow = ch;
             dmain++;
             std::get<1>(*FNit) = true;
+            if (highrow % ncols == ncols - 1) sealtoprow = true;
           }
           if (rowchange && ch == highrow + 1 && highrow != channel && triggertype == CbmTrdDigi::eTriggerType::kNeighbor
               && !std::get<1>(*FNit) && !sealtoprow) {
@@ -586,6 +604,8 @@ bool CbmTrdModuleRecR::IsClusterComplete(const CbmTrdCluster* cluster)
 {
   int colMin = fDigiPar->GetNofColumns();
   int rowMin = fDigiPar->GetNofRows();
+  int colMax = 0;
+  int rowMax = 0;
 
   for (int i = 0; i < cluster->GetNofDigis(); ++i) {
     const CbmTrdDigi* digi = CbmDigiManager::Instance()->Get<CbmTrdDigi>(cluster->GetDigi(i));
@@ -594,10 +614,12 @@ bool CbmTrdModuleRecR::IsClusterComplete(const CbmTrdCluster* cluster)
 
     if (digiCol < colMin) colMin = digiCol;
     if (digiRow < rowMin) rowMin = digiRow;
+    if (digiCol > colMax) colMax = digiCol;
+    if (digiRow > rowMax) rowMax = digiRow;
   }
 
-  const UShort_t nCols = cluster->GetNCols();
-  const UShort_t nRows = cluster->GetNRows();
+  const UShort_t nCols = colMax - colMin + 1;
+  const UShort_t nRows = rowMax - rowMin + 1;
 
   CbmTrdDigi* digiMap[nRows][nCols];                        //create array on stack for optimal performance
   memset(digiMap, 0, sizeof(CbmTrdDigi*) * nCols * nRows);  //init with nullpointers