preserve the sign from the esd label in the aod track

[u/mrichter/AliRoot.git] / STEER / AliAODHandler.cxx

diff --git a/STEER/AliAODHandler.cxx b/STEER/AliAODHandler.cxx
index 005ccd1d4ba9345eb6c8ac4e0ef74f51f24c3481..bb320a72b15cdc9e106a596cf4503dd10506d037 100644 (file)
--- a/STEER/AliAODHandler.cxx
+++ b/STEER/AliAODHandler.cxx
@@ -315,17 +315,21 @@ void AliAODHandler::StoreMCParticles(){
     for(int it = 0; it < fAODEvent->GetNTracks();++it){
       AliAODTrack *track = fAODEvent->GetTrack(it);
       
-      Int_t label = TMath::Abs(track->GetLabel());
+      Int_t sign = 1;
+      Int_t label = track->GetLabel();
+      if(label<0){ // preserve the sign for later usage
+       label *= -1;
+       sign  = -1;
+      }
+
       if (label >= AliMCEvent::BgLabelOffset()) label =  mcEvent->BgLabelToIndex(label);
-      
-      
       if(label > np || track->GetLabel() == 0){
        AliWarning(Form("Wrong ESD track label %5d (%5d)",track->GetLabel(), label));
       }
       if(fMCEventH->GetNewLabel(label) == 0){
        AliWarning(Form("New label not found for %5d (%5d)",track->GetLabel(), label));
       }
-      track->SetLabel(fMCEventH->GetNewLabel(label));
+      track->SetLabel(sign*fMCEventH->GetNewLabel(label));
     }
   }