Merge branch '21.0-ATLASSIM-5297' into '21.0'

Retry simulation if FCal cell assignment fails

See merge request atlas/athena!45158

Simulation/ISF/ISF_FastCaloSim/ISF_FastCaloSimEvent/src/TFCSHitCellMappingFCal.cxx

@@ -16,12 +16,14 @@ FCSReturnCode TFCSHitCellMappingFCal::simulate_hit(Hit& hit,TFCSSimulationState&
   int cs=calosample();
   const CaloDetDescrElement* cellele=m_geo->getFCalDDE(cs,hit.x(),hit.y(),hit.z());
   ATH_MSG_DEBUG("HIT: cellele="<<cellele<<" E="<<hit.E()<<" cs="<<cs<<" x="<<hit.x()<<" y="<<hit.y() << " z="<<hit.z());
-  if(cellele) {
-    simulstate.deposit(cellele,hit.E());
-  } else {
-    ATH_MSG_ERROR("TFCSLateralShapeParametrizationHitCellMapping::simulate_hit: cellele="<<cellele<<" E="<<hit.E()<<" cs="<<cs<<" eta="<<hit.eta()<<" phi="<<hit.phi());
-    return FCSFatal;
-  }
 
+  /// protection against cases where hits cannot be matched to a FCal cell 
+  if((hit.x() == 0 &&  hit.y() == 0) || cellele == 0) {
+    ATH_MSG_WARNING("TFCSLateralShapeParametrizationHitCellMapping::simulate_hit: cellele="<<cellele<<" E="<<hit.E()<<" cs="<<cs<<" eta="<<hit.eta()<<" phi="<<hit.phi());
+   return (FCSReturnCode)(FCSRetry+5); // retry simulation up to 5 times
+  }
+    
+  simulstate.deposit(cellele,hit.E());
+   
   return FCSSuccess;
 }