adding function to retrieve eta from tracklets

diff --git a/STEER/AliMultiplicity.h b/STEER/AliMultiplicity.h
index 8ab1308773d934127e4e17e684b9de556fd43e2f..952c650e50adefa92746635521f48ed15d25514e 100644 (file)
--- a/STEER/AliMultiplicity.h
+++ b/STEER/AliMultiplicity.h
@@ -2,6 +2,7 @@
 #define ALIMULTIPLICITY_H
 
 #include<TObject.h>
+#include<TMath.h>
 
 ////////////////////////////////////////////////////////
 ////   Class containing multiplicity information      //
@@ -23,6 +24,8 @@ class AliMultiplicity : public TObject {
   Int_t GetNumberOfTracklets() const {return fNtracks;}
   Double_t GetTheta(Int_t i) const { if(i>=0 && i<fNtracks) {return fTh[i];}
   else {Error("GetTheta","Invalid track number %d",i); return -9999.;}}
+  Double_t GetEta(Int_t i) const { if(i>=0 && i<fNtracks) {return -TMath::Log(TMath::Tan(fTh[i]/2.));}
+  else {Error("GetTheta","Invalid track number %d",i); return -9999.;}}
   Double_t GetPhi(Int_t i) const { if(i>=0 && i<fNtracks) {return fPhi[i];}
   else {Error("GetPhi","Invalid track number %d",i); return -9999.;}}
   Double_t GetDeltaPhi(Int_t i) const {if(i>=0 && i<fNtracks) {return fDeltPhi[i];}