-//_____________________________________________________________________________
-AliTPCcluster::AliTPCcluster() {
- //default constructor
- fTracks[0]=fTracks[1]=fTracks[2]=0;
- fY=fZ=fQ=fSigmaY2=fSigmaZ2=0.;
+//____________________________________________________________________________
+Double_t AliTPCcluster::SigmaY2(Double_t r, Double_t tgl, Double_t pt)
+{
+ //
+ // Parametrised error of the cluster reconstruction (pad direction)
+ //
+ // Sigma rphi
+ const Float_t kArphi=0.41818e-2;
+ const Float_t kBrphi=0.17460e-4;
+ const Float_t kCrphi=0.30993e-2;
+ const Float_t kDrphi=0.41061e-3;
+
+ pt=TMath::Abs(pt)*1000.;
+ Double_t x=r/pt;
+ tgl=TMath::Abs(tgl);
+ Double_t s=kArphi - kBrphi*r*tgl + kCrphi*x*x + kDrphi*x;
+ if (s<0.4e-3) s=0.4e-3;
+ s*=1.3; //Iouri Belikov
+
+ return s;