3 /* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * See cxx source for full Copyright notice */
10 //-------------------------------------------------------
13 // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
14 //-------------------------------------------------------
16 /*****************************************************************************
18 * Internal view of the TPC track parametrisation as well as the order of *
19 * track parameters are subject for possible changes ! *
20 * Use GetExternalParameters() and GetExternalCovariance() to access TPC *
21 * track information regardless of its internal representation. *
22 * This formation is now fixed in the following way: *
23 * external param0: local Y-coordinate of a track (cm) *
24 * external param1: local Z-coordinate of a track (cm) *
25 * external param2: local sine of the track momentum azimuth angle *
26 * external param3: tangent of the track momentum dip angle *
27 * external param4: 1/pt (1/(GeV/c)) *
28 *****************************************************************************/
30 #include <AliKalmanTrack.h>
33 #include "AliTPCreco.h"
35 //_____________________________________________________________________________
36 class AliTPCtrack : public AliKalmanTrack {
39 AliTPCtrack(UInt_t index, const Double_t xx[5],
40 const Double_t cc[15], Double_t xr, Double_t alpha);
41 AliTPCtrack(const AliKalmanTrack& t, Double_t alpha);
42 AliTPCtrack(const AliTPCtrack& t);
43 virtual ~AliTPCtrack() {}
44 Int_t PropagateToVertex(Double_t x0=36.66,Double_t rho=1.2e-3);
45 Int_t Rotate(Double_t angle);
46 void SetdEdx(Double_t dedx) {fdEdx=dedx;}
48 Double_t GetX() const {return fX;}
49 Double_t GetAlpha() const {return fAlpha;}
50 Double_t GetdEdx() const {return fdEdx;}
52 Double_t GetY() const {return fP0;}
53 Double_t GetZ() const {return fP1;}
54 Double_t GetSnp() const {return fX*fP4 - fP2;}
56 Get1Pt() const { return (1e-9*TMath::Abs(fP4)/fP4 + fP4)*GetConvConst(); }
57 Double_t GetTgl() const {return fP3;}
59 Double_t GetSigmaY2() const {return fC00;}
60 Double_t GetSigmaZ2() const {return fC11;}
62 // Some methods useful for users. Implementation is not
63 // optimized for speed but for minimal maintanance effort
65 Double_t Theta() const {return TMath::Pi()/2.-TMath::ATan(GetTgl());}
66 Double_t Px() const {return TMath::Cos(Phi())/TMath::Abs(Get1Pt());}
67 Double_t Py() const {return TMath::Sin(Phi())/TMath::Abs(Get1Pt());}
68 Double_t Pz() const {return GetTgl()/TMath::Abs(Get1Pt());}
69 Double_t Pt() const {return 1./TMath::Abs(Get1Pt());}
70 Double_t P() const {return TMath::Sqrt(Pt()*Pt()+Pz()*Pz());}
72 Int_t Compare(const TObject *o) const;
74 void GetExternalParameters(Double_t& xr, Double_t x[5]) const ;
75 void GetExternalCovariance(Double_t cov[15]) const ;
77 Int_t GetClusterIndex(Int_t i) const {return fIndex[i];}
79 //******** To be removed next release !!! **************
80 Double_t GetEta() const {return fP2;}
81 Double_t GetC() const {return fP4;}
82 void GetCovariance(Double_t cc[15]) const {
84 cc[1 ]=fC10; cc[2 ]=fC11;
85 cc[3 ]=fC20; cc[4 ]=fC21; cc[5 ]=fC22;
86 cc[6 ]=fC40; cc[7 ]=fC41; cc[8 ]=fC42; cc[9 ]=fC44;
87 cc[10]=fC30; cc[11]=fC31; cc[12]=fC32; cc[13]=fC43; cc[14]=fC33;
89 //******************************************************
91 virtual Double_t GetPredictedChi2(const AliCluster *cluster) const;
92 Int_t PropagateTo(Double_t xr,Double_t x0=28.94,Double_t rho=0.9e-3);
93 Int_t Update(const AliCluster* c, Double_t chi2, UInt_t i);
94 void ResetCovariance();
97 Double_t fX; // X-coordinate of this track (reference plane)
98 Double_t fAlpha; // Rotation angle the local (TPC sector)
99 // coordinate system and the global ALICE one.
101 Double_t fdEdx; // dE/dx
103 Double_t fP0; // Y-coordinate of a track
104 Double_t fP1; // Z-coordinate of a track
105 Double_t fP2; // C*x0
106 Double_t fP3; // tangent of the track momentum dip angle
107 Double_t fP4; // track curvature
109 Double_t fC00; // covariance
110 Double_t fC10, fC11; // matrix
111 Double_t fC20, fC21, fC22; // of the
112 Double_t fC30, fC31, fC32, fC33; // track
113 Double_t fC40, fC41, fC42, fC43, fC44; // parameters
115 UInt_t fIndex[kMaxRow]; // indices of associated clusters
117 ClassDef(AliTPCtrack,1) // Time Projection Chamber reconstructed tracks
121 void AliTPCtrack::GetExternalParameters(Double_t& xr, Double_t x[5]) const {
122 //---------------------------------------------------------------------
123 // This function return external TPC track representation
124 //---------------------------------------------------------------------
126 x[0]=GetY(); x[1]=GetZ(); x[2]=GetSnp(); x[3]=GetTgl(); x[4]=Get1Pt();