/* $Id$ */
-
+/*****************************************************************************
+ * "External" track parametrisation class *
+ * *
+ * external param0: local Y-coordinate of a track (cm) *
+ * external param1: local Z-coordinate of a track (cm) *
+ * external param2: local sine of the track momentum azimuthal angle *
+ * external param3: tangent of the track momentum dip angle *
+ * external param4: 1/pt (1/(GeV/c)) *
+ * *
+ * The parameters are estimated at an exact position x in a local coord. *
+ * system rotated by angle alpha with respect to the global coord.system. *
+ * Origin: I.Belikov, CERN, Jouri.Belikov@cern.ch *
+ *****************************************************************************/
#include "TObject.h"
+#include "TMath.h"
+
+const Double_t kAlmost1=0.999;
+const Double_t kAlmost0=1e-33;
+const Double_t kVeryBig=1./kAlmost0;
+
+const Double_t kB2C=0.299792458e-3;
+const Double_t kAlmost0Field=1.e-13;
+const Double_t kMostProbablePt=0.35;
-class AliKalmanTrack;
+class AliESDVertex;
+
+Double_t ApproximateBetheBloch(Double_t);
class AliExternalTrackParam: public TObject {
public:
AliExternalTrackParam();
+ AliExternalTrackParam(const AliExternalTrackParam &);
AliExternalTrackParam(Double_t x, Double_t alpha,
const Double_t param[5], const Double_t covar[15]);
- AliExternalTrackParam(const AliKalmanTrack& track);
+ virtual ~AliExternalTrackParam(){}
+ void Set(Double_t x,Double_t alpha,
+ const Double_t param[5], const Double_t covar[15]);
void Reset();
- void Set(const AliKalmanTrack& track);
+ void ResetCovariance(Double_t s2) {
+ fC[0]*= s2;
+ fC[1] = 0.; fC[2]*= s2;
+ fC[3] = 0.; fC[4] = 0.; fC[5]*= s2;
+ fC[6] = 0.; fC[7] = 0.; fC[8] = 0.; fC[9]*= s2;
+ fC[10]= 0.; fC[11]= 0.; fC[12]= 0.; fC[13]= 0.; fC[14]*=s2;
+ }
+
+ const Double_t *GetParameter() const {return fP;}
+ const Double_t *GetCovariance() const {return fC;}
+
+ Double_t GetAlpha() const {return fAlpha;}
+ Double_t GetX() const {return fX;}
+ Double_t GetY() const {return fP[0];}
+ Double_t GetZ() const {return fP[1];}
+ Double_t GetSnp() const {return fP[2];}
+ Double_t GetTgl() const {return fP[3];}
+ Double_t Get1Pt() const {return fP[4];}
+
+ Double_t GetSigmaY2() const {return fC[0];}
+ Double_t GetSigmaZY() const {return fC[1];}
+ Double_t GetSigmaZ2() const {return fC[2];}
+ Double_t GetSigmaSnpY() const {return fC[3];}
+ Double_t GetSigmaSnpZ() const {return fC[4];}
+ Double_t GetSigmaSnp2() const {return fC[5];}
+ Double_t GetSigmaTglY() const {return fC[6];}
+ Double_t GetSigmaTglZ() const {return fC[7];}
+ Double_t GetSigmaTglSnp() const {return fC[8];}
+ Double_t GetSigmaTgl2() const {return fC[9];}
+ Double_t GetSigma1PtY() const {return fC[10];}
+ Double_t GetSigma1PtZ() const {return fC[11];}
+ Double_t GetSigma1PtSnp() const {return fC[12];}
+ Double_t GetSigma1PtTgl() const {return fC[13];}
+ Double_t GetSigma1Pt2() const {return fC[14];}
- const Double_t* GetParameter() const {return fP;}
- const Double_t* GetCovariance() const {return fC;}
- virtual Double_t GetX() const {return fX;}
- virtual Double_t GetAlpha() const {return fAlpha;}
Double_t GetSign() const {return (fP[4]>0) ? 1 : -1;}
Double_t GetP() const;
- Double_t GetD(Double_t b, Double_t x=0, Double_t y=0) const;
+ Double_t GetPt() const {
+ return (TMath::Abs(fP[4])>kAlmost0) ? 1./fP[4]:TMath::Sign(kVeryBig,fP[4]);
+ }
+ Double_t Get1P() const;
+ Double_t GetC(Double_t b) const {return fP[4]*b*kB2C;}
+ void GetDZ(Double_t x,Double_t y,Double_t z,Double_t b,Float_t dz[2]) const;
+ Double_t GetD(Double_t xv, Double_t yv, Double_t b) const;
+ Double_t GetLinearD(Double_t xv, Double_t yv) const;
+ Bool_t CorrectForMaterial(Double_t d, Double_t x0, Double_t mass,
+ Double_t (*f)(Double_t)=ApproximateBetheBloch);
+ Double_t GetPredictedChi2(Double_t p[2],Double_t cov[3]) const;
+ Bool_t Update(Double_t p[2],Double_t cov[3]);
+ Bool_t Rotate(Double_t alpha);
+ Bool_t PropagateTo(Double_t x, Double_t b);
+ Bool_t Propagate(Double_t alpha, Double_t x, Double_t b) {
+ if (Rotate(alpha))
+ if (PropagateTo(x,b)) return kTRUE;
+ return kFALSE;
+ }
+ void Propagate(Double_t len,Double_t x[3],Double_t p[3],Double_t bz) const;
+ Bool_t Intersect(Double_t pnt[3], Double_t norm[3], Double_t bz) const;
+
+ void GetHelixParameters(Double_t h[6], Double_t b) const;
+ Double_t GetDCA(const AliExternalTrackParam *p, Double_t b,
+ Double_t &xthis,Double_t &xp) const;
+ Double_t PropagateToDCA(AliExternalTrackParam *p, Double_t b);
+ Bool_t PropagateToDCA(const AliESDVertex *vtx, Double_t b, Double_t maxd);
+
+ void GetDirection(Double_t d[3]) const;
Bool_t GetPxPyPz(Double_t *p) const;
Bool_t GetXYZ(Double_t *p) const;
Bool_t GetCovarianceXYZPxPyPz(Double_t cv[21]) const;
Bool_t GetPxPyPzAt(Double_t x, Double_t b, Double_t p[3]) const;
Bool_t GetXYZAt(Double_t x, Double_t b, Double_t r[3]) const;
-
+ Bool_t GetYAt(Double_t x, Double_t b, Double_t &y) const;
+ Bool_t GetZAt(Double_t x, Double_t b, Double_t &z) const;
void Print(Option_t* option = "") const;
+ Double_t GetSnpAt(Double_t x,Double_t b) const;
+
+protected:
+ Double_t &Par(Int_t i) {return fP[i];}
+ Double_t &Cov(Int_t i) {return fC[i];}
private:
- Double_t fX; // x coordinate for the parametrisation
- Double_t fAlpha; // azimuthal angle for the parametrisation
- Double_t fP[5]; // track parameter (y, z, sin(azimuthal angel), tan(dip angle), 1/pt)
- Double_t fC[15]; // track parameter covariance
+ Double32_t fX; // X coordinate for the point of parametrisation
+ Double32_t fAlpha; // Local <-->global coor.system rotation angle
+ Double32_t fP[5]; // The track parameters
+ Double32_t fC[15]; // The track parameter covariance matrix
- ClassDef(AliExternalTrackParam, 4)
+ ClassDef(AliExternalTrackParam, 5)
};
#endif
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff