+ virtual void SetVtxStart(Double_t x,Double_t y,Double_t z)
+ { fNominalPos[0]=x; fNominalPos[1]=y; fNominalPos[2]=z; }
+ virtual void SetVtxStartSigma(Double_t sx,Double_t sy,Double_t sz)
+ { fNominalCov[0]=sx*sx; fNominalCov[2]=sy*sy; fNominalCov[5]=sz*sz;
+ fNominalCov[1]=0.; fNominalCov[3]=0.; fNominalCov[4]=0.; }
+ virtual void SetVtxStart(AliESDVertex *vtx);