GPU TPC: Fix segfault when TPC occupancy map is not requested

Author: davidrohr

GPU/GPUTracking/Global/GPUChainTrackingSliceTracker.cxx

@@ -164,9 +164,11 @@ int32_t GPUChainTracking::RunTPCTrackingSlices_internal()
       TransferMemoryResourceLinkToGPU(RecoStep::TPCSliceTracking, mInputsHost->mResourceOccupancyMap, streamOccMap, &mEvents->init);
     }
   }
-  uint32_t& occupancyTotal = *mInputsHost->mTPCClusterOccupancyMap;
-  occupancyTotal = CAMath::Float2UIntRn(mRec->MemoryScalers()->nTPCHits / (mIOPtrs.settingsTF && mIOPtrs.settingsTF->hasNHBFPerTF ? mIOPtrs.settingsTF->nHBFPerTF : 128));
-  mRec->UpdateParamOccupancyMap(param().rec.tpc.occupancyMapTimeBins ? mInputsHost->mTPCClusterOccupancyMap + 2 : nullptr, param().rec.tpc.occupancyMapTimeBins ? mInputsShadow->mTPCClusterOccupancyMap + 2 : nullptr, occupancyTotal, streamOccMap);
+  if (param().rec.tpc.occupancyMapTimeBins || param().rec.tpc.sysClusErrorC12Norm) {
+    uint32_t& occupancyTotal = *mInputsHost->mTPCClusterOccupancyMap;
+    occupancyTotal = CAMath::Float2UIntRn(mRec->MemoryScalers()->nTPCHits / (mIOPtrs.settingsTF && mIOPtrs.settingsTF->hasNHBFPerTF ? mIOPtrs.settingsTF->nHBFPerTF : 128));
+    mRec->UpdateParamOccupancyMap(param().rec.tpc.occupancyMapTimeBins ? mInputsHost->mTPCClusterOccupancyMap + 2 : nullptr, param().rec.tpc.occupancyMapTimeBins ? mInputsShadow->mTPCClusterOccupancyMap + 2 : nullptr, occupancyTotal, streamOccMap);
+  }
 
   int32_t streamMap[NSLICES];