[u/mrichter/AliRoot.git] / TPC / AliTPCtrack.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

/* $Id$ */

//-----------------------------------------------------------------
//           Implementation of the TPC track class
//        This class is used by the AliTPCtracker class
//      Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
//-----------------------------------------------------------------

#include <Riostream.h>

#include "AliTPCtrack.h"
#include "AliCluster.h"
#include "AliBarrelTrack.h"
#include "AliESDtrack.h"

ClassImp(AliTPCtrack)

//_________________________________________________________________________
AliTPCtrack::AliTPCtrack(): AliKalmanTrack() 
{
  fX = fP0 = fP1 = fP2 = fP3 = fP3 = fP4 = 0.0;
  fAlpha = fdEdx = 0.0;
  fNWrong = fNRotation = fNumber = 0;  // [SR, 01.04.2003]
}

//_________________________________________________________________________
AliTPCtrack::AliTPCtrack(UInt_t index, const Double_t xx[5],
const Double_t cc[15], Double_t xref, Double_t alpha) : AliKalmanTrack() {
  //-----------------------------------------------------------------
  // This is the main track constructor.
  //-----------------------------------------------------------------
  fX=xref;
  fAlpha=alpha;
  if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
  if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
  fdEdx=0.;

  fP0=xx[0]; fP1=xx[1]; fP2=xx[2]; fP3=xx[3]; fP4=xx[4];

  fC00=cc[0];
  fC10=cc[1];  fC11=cc[2];
  fC20=cc[3];  fC21=cc[4];  fC22=cc[5];
  fC30=cc[6];  fC31=cc[7];  fC32=cc[8];  fC33=cc[9];
  fC40=cc[10]; fC41=cc[11]; fC42=cc[12]; fC43=cc[13]; fC44=cc[14];

  fIndex[0]=index;
  SetNumberOfClusters(1);

}

//_____________________________________________________________________________
AliTPCtrack::AliTPCtrack(const AliKalmanTrack& t,Double_t alpha) :
AliKalmanTrack(t) {
  //-----------------------------------------------------------------
  // Conversion AliKalmanTrack -> AliTPCtrack.
  //-----------------------------------------------------------------
  SetChi2(0.);
  SetNumberOfClusters(0);

  fdEdx  = 0.;
  fAlpha = alpha;
  if      (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
  else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();

  //Conversion of the track parameters
  Double_t x,p[5]; t.GetExternalParameters(x,p);
  fX=x;    x=GetConvConst();
  fP0=p[0]; 
  fP1=p[1]; 
  fP3=p[3];
  fP4=p[4]/x; 
  fP2=fP4*fX - p[2];

  //Conversion of the covariance matrix
  Double_t c[15]; t.GetExternalCovariance(c);
  c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x;

  Double_t c22=fX*fX*c[14] - 2*fX*c[12] + c[5];
  Double_t c32=fX*c[13] - c[8];
  Double_t c20=fX*c[10] - c[3], c21=fX*c[11] - c[4], c42=fX*c[14] - c[12];
  
  fC00=c[0 ];
  fC10=c[1 ];   fC11=c[2 ];
  fC20=c20;     fC21=c21;     fC22=c22;
  fC30=c[6 ];   fC31=c[7 ];   fC32=c32;   fC33=c[9 ];
  fC40=c[10];   fC41=c[11];   fC42=c42;   fC43=c[13]; fC44=c[14];

}

//_____________________________________________________________________________
AliTPCtrack::AliTPCtrack(const AliESDtrack& t) : AliKalmanTrack() {
  //-----------------------------------------------------------------
  // Conversion AliESDtrack -> AliTPCtrack.
  //-----------------------------------------------------------------
  SetNumberOfClusters(t.GetTPCclusters(fIndex));
  SetLabel(t.GetLabel());
  SetMass(t.GetMass());

  fdEdx  = t.GetTPCsignal();
  fAlpha = t.GetAlpha();
  if      (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
  else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();

  //Conversion of the track parameters
  Double_t x,p[5]; t.GetExternalParameters(x,p);
  fX=x;    x=GetConvConst();
  fP0=p[0];
  fP1=p[1];
  fP3=p[3];
  fP4=p[4]/x;
  fP2=fP4*fX - p[2];

  //Conversion of the covariance matrix
  Double_t c[15]; t.GetExternalCovariance(c);
  c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x;

  Double_t c22=fX*fX*c[14] - 2*fX*c[12] + c[5];
  Double_t c32=fX*c[13] - c[8];
  Double_t c20=fX*c[10] - c[3], c21=fX*c[11] - c[4], c42=fX*c[14] - c[12];

  fC00=c[0 ];
  fC10=c[1 ];   fC11=c[2 ];
  fC20=c20;     fC21=c21;     fC22=c22;
  fC30=c[6 ];   fC31=c[7 ];   fC32=c32;   fC33=c[9 ];
  fC40=c[10];   fC41=c[11];   fC42=c42;   fC43=c[13]; fC44=c[14];

  if ((t.GetStatus()&AliESDtrack::kTIME) == 0) return;
  StartTimeIntegral();
  Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
  SetIntegratedLength(t.GetIntegratedLength());
}

//_____________________________________________________________________________
AliTPCtrack::AliTPCtrack(const AliTPCtrack& t) : AliKalmanTrack(t) {
  //-----------------------------------------------------------------
  // This is a track copy constructor.
  //-----------------------------------------------------------------
  fX=t.fX;
  fAlpha=t.fAlpha;
  fdEdx=t.fdEdx;

  fP0=t.fP0; fP1=t.fP1; fP2=t.fP2; fP3=t.fP3; fP4=t.fP4;

  fC00=t.fC00;
  fC10=t.fC10;  fC11=t.fC11;
  fC20=t.fC20;  fC21=t.fC21;  fC22=t.fC22;
  fC30=t.fC30;  fC31=t.fC31;  fC32=t.fC32;  fC33=t.fC33;
  fC40=t.fC40;  fC41=t.fC41;  fC42=t.fC42;  fC43=t.fC43;  fC44=t.fC44;

  Int_t n=GetNumberOfClusters();
  for (Int_t i=0; i<n; i++) fIndex[i]=t.fIndex[i];
}
//_____________________________________________________________________________

void  AliTPCtrack::GetBarrelTrack(AliBarrelTrack *track) {
  //
  // Create a Barrel Track out of this track
  // Current track is propagated to the reference plane
  // by the tracker
  //
  // [SR, 01.04.2003]
  
  if (!track) return;
  Double_t xr, vec[5], cov[15];

  track->SetLabel(GetLabel());
  track->SetX(fX, fAlpha);
  track->SetNClusters(GetNumberOfClusters(), GetChi2());
  Double_t times[10];
  GetIntegratedTimes(times);
  track->SetTime(times, GetIntegratedLength());

  track->SetMass(GetMass());
  track->SetdEdX(GetdEdx());

  track->SetNWrongClusters(fNWrong);
  track->SetNRotate(fNRotation);

  GetExternalParameters(xr, vec);
  track->SetStateVector(vec);
  
  GetExternalCovariance(cov);
  track->SetCovarianceMatrix(cov);

}
//_____________________________________________________________________________
Int_t AliTPCtrack::Compare(const TObject *o) const {
  //-----------------------------------------------------------------
  // This function compares tracks according to the their curvature
  //-----------------------------------------------------------------
  AliTPCtrack *t=(AliTPCtrack*)o;
  //Double_t co=TMath::Abs(t->Get1Pt());
  //Double_t c =TMath::Abs(Get1Pt());
  Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
  Double_t c =GetSigmaY2()*GetSigmaZ2();
  if (c>co) return 1;
  else if (c<co) return -1;
  return 0;
}

//_____________________________________________________________________________
void AliTPCtrack::GetExternalCovariance(Double_t cc[15]) const {
  //-------------------------------------------------------------------------
  // This function returns an external representation of the covriance matrix.
  //   (See comments in AliTPCtrack.h about external track representation)
  //-------------------------------------------------------------------------
  Double_t a=GetConvConst();

  Double_t c22=fX*fX*fC44-2*fX*fC42+fC22;
  Double_t c32=fX*fC43-fC32;
  Double_t c20=fX*fC40-fC20, c21=fX*fC41-fC21, c42=fX*fC44-fC42;
  
  cc[0 ]=fC00;
  cc[1 ]=fC10;   cc[2 ]=fC11;
  cc[3 ]=c20;    cc[4 ]=c21;    cc[5 ]=c22;
  cc[6 ]=fC30;   cc[7 ]=fC31;   cc[8 ]=c32;   cc[9 ]=fC33; 
  cc[10]=fC40*a; cc[11]=fC41*a; cc[12]=c42*a; cc[13]=fC43*a; cc[14]=fC44*a*a;

}

//_____________________________________________________________________________
Double_t AliTPCtrack::GetPredictedChi2(const AliCluster *c) const 
{
  //-----------------------------------------------------------------
  // This function calculates a predicted chi2 increment.
  //-----------------------------------------------------------------
  Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
  r00+=fC00; r01+=fC10; r11+=fC11;

  Double_t det=r00*r11 - r01*r01;
  if (TMath::Abs(det) < 1.e-10) {
    Int_t n=GetNumberOfClusters();
    if (n>4) cerr<<n<<" AliKalmanTrack warning: Singular matrix !\n";
    return 1e10;
  }
  Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01;
  
  Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1;
  
  return (dy*r00*dy + 2*r01*dy*dz + dz*r11*dz)/det;
}

Double_t AliTPCtrack::GetYat(Double_t xk) const {
//-----------------------------------------------------------------
// This function calculates the Y-coordinate of a track at the plane x=xk.
//-----------------------------------------------------------------
    Double_t c1=fP4*fX - fP2, r1=TMath::Sqrt(1.- c1*c1);
    Double_t c2=fP4*xk - fP2, r2=TMath::Sqrt(1.- c2*c2);
    return fP0 + (xk-fX)*(c1+c2)/(r1+r2);
}

//_____________________________________________________________________________
Int_t AliTPCtrack::PropagateTo(Double_t xk,Double_t x0,Double_t rho) {
  //-----------------------------------------------------------------
  // This function propagates a track to a reference plane x=xk.
  //-----------------------------------------------------------------
  if (TMath::Abs(fP4*xk - fP2) >= 0.9) {
    //    Int_t n=GetNumberOfClusters();
    //if (n>4) cerr<<n<<" AliTPCtrack warning: Propagation failed !\n";
    return 0;
  }
  
  // old position for time [SR, GSI 17.02.2003]
  Double_t oldX = fX;
  Double_t oldY = fP0;
  Double_t oldZ = fP1;
  //

  Double_t x1=fX, x2=x1+(xk-x1), dx=x2-x1, y1=fP0, z1=fP1;
  Double_t c1=fP4*x1 - fP2, r1=sqrt(1.- c1*c1);
  Double_t c2=fP4*x2 - fP2, r2=sqrt(1.- c2*c2);
  
  fP0 += dx*(c1+c2)/(r1+r2);
  fP1 += dx*(c1+c2)/(c1*r2 + c2*r1)*fP3;

  //f = F - 1
  Double_t rr=r1+r2, cc=c1+c2, xx=x1+x2;
  Double_t f02=-dx*(2*rr + cc*(c1/r1 + c2/r2))/(rr*rr);
  Double_t f04= dx*(rr*xx + cc*(c1*x1/r1+c2*x2/r2))/(rr*rr);
  Double_t cr=c1*r2+c2*r1;
  Double_t f12=-dx*fP3*(2*cr + cc*(c2*c1/r1-r1 + c1*c2/r2-r2))/(cr*cr);
  Double_t f13= dx*cc/cr; 
  Double_t f14=dx*fP3*(cr*xx-cc*(r1*x2-c2*c1*x1/r1+r2*x1-c1*c2*x2/r2))/(cr*cr);

  //b = C*ft
  Double_t b00=f02*fC20 + f04*fC40, b01=f12*fC20 + f14*fC40 + f13*fC30;
  Double_t b10=f02*fC21 + f04*fC41, b11=f12*fC21 + f14*fC41 + f13*fC31;
  Double_t b20=f02*fC22 + f04*fC42, b21=f12*fC22 + f14*fC42 + f13*fC32;
  Double_t b30=f02*fC32 + f04*fC43, b31=f12*fC32 + f14*fC43 + f13*fC33;
  Double_t b40=f02*fC42 + f04*fC44, b41=f12*fC42 + f14*fC44 + f13*fC43;
  
  //a = f*b = f*C*ft
  Double_t a00=f02*b20+f04*b40,a01=f02*b21+f04*b41,a11=f12*b21+f14*b41+f13*b31;

  //F*C*Ft = C + (a + b + bt)
  fC00 += a00 + 2*b00;
  fC10 += a01 + b01 + b10; 
  fC20 += b20;
  fC30 += b30;
  fC40 += b40;
  fC11 += a11 + 2*b11;
  fC21 += b21; 
  fC31 += b31; 
  fC41 += b41; 

  fX=x2;

  //Multiple scattering******************
  Double_t d=sqrt((x1-fX)*(x1-fX)+(y1-fP0)*(y1-fP0)+(z1-fP1)*(z1-fP1));
  Double_t p2=(1.+ GetTgl()*GetTgl())/(Get1Pt()*Get1Pt());
  Double_t beta2=p2/(p2 + GetMass()*GetMass());
  //Double_t theta2=14.1*14.1/(beta2*p2*1e6)*d/x0*rho;
  Double_t theta2=1.0259e-6*10*10/20/(beta2*p2)*d*rho;

  Double_t ey=fP4*fX - fP2, ez=fP3;
  Double_t xz=fP4*ez, zz1=ez*ez+1, xy=fP2+ey;

  fC22 += (2*ey*ez*ez*fP2+1-ey*ey+ez*ez+fP2*fP2*ez*ez)*theta2;
  fC32 += ez*zz1*xy*theta2;
  fC33 += zz1*zz1*theta2;
  fC42 += xz*ez*xy*theta2;
  fC43 += xz*zz1*theta2;
  fC44 += xz*xz*theta2;

  //Energy losses************************
  Double_t dE=0.153e-3/beta2*(log(5940*beta2/(1-beta2)) - beta2)*d*rho;
  if (x1 < x2) dE=-dE;
  cc=fP4;
  fP4*=(1.- sqrt(p2+GetMass()*GetMass())/p2*dE);
  fP2+=fX*(fP4-cc);

  // Integrated Time [SR, GSI, 17.02.2003]
  if (IsStartedTimeIntegral()) {
    Double_t l2 = (fX-oldX)*(fX-oldX)+(fP0-oldY)*(fP0-oldY)+(fP1-oldZ)*(fP1-oldZ);
    AddTimeStep(TMath::Sqrt(l2));
  }
  //

  return 1;
}

//_____________________________________________________________________________
Int_t AliTPCtrack::PropagateToVertex(Double_t x0,Double_t rho) 
{
  //-----------------------------------------------------------------
  // This function propagates tracks to the "vertex".
  //-----------------------------------------------------------------
  Double_t c=fP4*fX - fP2;
  Double_t tgf=-fP2/(fP4*fP0 + sqrt(1-c*c));
  Double_t snf=tgf/sqrt(1.+ tgf*tgf);
  Double_t xv=(fP2+snf)/fP4;
  return PropagateTo(xv,x0,rho);
}

//_____________________________________________________________________________
Int_t AliTPCtrack::Update(const AliCluster *c, Double_t chisq, UInt_t index) {
  //-----------------------------------------------------------------
  // This function associates a cluster with this track.
  //-----------------------------------------------------------------

  // update the number of wrong SR[20.03.2003]
  Int_t absLabel = TMath::Abs(GetLabel());
  if ( (c->GetLabel(0) != absLabel) && 
       (c->GetLabel(0) != absLabel) &&
       (c->GetLabel(0) != absLabel)) fNWrong++;
  //

  Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
  r00+=fC00; r01+=fC10; r11+=fC11;
  Double_t det=r00*r11 - r01*r01;
  Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;

  Double_t k00=fC00*r00+fC10*r01, k01=fC00*r01+fC10*r11;
  Double_t k10=fC10*r00+fC11*r01, k11=fC10*r01+fC11*r11;
  Double_t k20=fC20*r00+fC21*r01, k21=fC20*r01+fC21*r11;
  Double_t k30=fC30*r00+fC31*r01, k31=fC30*r01+fC31*r11;
  Double_t k40=fC40*r00+fC41*r01, k41=fC40*r01+fC41*r11;

  Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1;
  Double_t cur=fP4 + k40*dy + k41*dz, eta=fP2 + k20*dy + k21*dz;
  if (TMath::Abs(cur*fX-eta) >= 0.9) {
    //    Int_t n=GetNumberOfClusters();
    //if (n>4) cerr<<n<<" AliTPCtrack warning: Filtering failed !\n";
    return 0;
  }

  fP0 += k00*dy + k01*dz;
  fP1 += k10*dy + k11*dz;
  fP2  = eta;
  fP3 += k30*dy + k31*dz;
  fP4  = cur;

  Double_t c01=fC10, c02=fC20, c03=fC30, c04=fC40;
  Double_t c12=fC21, c13=fC31, c14=fC41;

  fC00-=k00*fC00+k01*fC10; fC10-=k00*c01+k01*fC11;
  fC20-=k00*c02+k01*c12;   fC30-=k00*c03+k01*c13;
  fC40-=k00*c04+k01*c14; 

  fC11-=k10*c01+k11*fC11;
  fC21-=k10*c02+k11*c12;   fC31-=k10*c03+k11*c13;
  fC41-=k10*c04+k11*c14; 

  fC22-=k20*c02+k21*c12;   fC32-=k20*c03+k21*c13;
  fC42-=k20*c04+k21*c14; 

  fC33-=k30*c03+k31*c13;
  fC43-=k40*c03+k41*c13; 

  fC44-=k40*c04+k41*c14; 

  Int_t n=GetNumberOfClusters();
  fIndex[n]=index;
  SetNumberOfClusters(n+1);
  SetChi2(GetChi2()+chisq);

  return 1;
}

//_____________________________________________________________________________
Int_t AliTPCtrack::Rotate(Double_t alpha)
{
  //-----------------------------------------------------------------
  // This function rotates this track.
  //-----------------------------------------------------------------

  if (alpha != 0) fNRotation++;  // [SR, 01.04.2003]

  fAlpha += alpha;
  if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
  if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
  
  Double_t x1=fX, y1=fP0;
  Double_t ca=cos(alpha), sa=sin(alpha);
  Double_t r1=fP4*fX - fP2;
  
  fX = x1*ca + y1*sa;
  fP0=-x1*sa + y1*ca;
  fP2=fP2*ca + (fP4*y1 + sqrt(1.- r1*r1))*sa;
  
  Double_t r2=fP4*fX - fP2;
  if (TMath::Abs(r2) >= 0.99999) {
    Int_t n=GetNumberOfClusters();
    if (n>4) cerr<<n<<" AliTPCtrack warning: Rotation failed !\n";
    return 0;
  }
  
  Double_t y0=fP0 + sqrt(1.- r2*r2)/fP4;
  if ((fP0-y0)*fP4 >= 0.) {
    Int_t n=GetNumberOfClusters();
    if (n>4) cerr<<n<<" AliTPCtrack warning: Rotation failed !!!\n";
    return 0;
  }

  //f = F - 1
  Double_t f00=ca-1,    f24=(y1 - r1*x1/sqrt(1.- r1*r1))*sa, 
           f20=fP4*sa,  f22=(ca + sa*r1/sqrt(1.- r1*r1))-1;

  //b = C*ft
  Double_t b00=fC00*f00, b02=fC00*f20+fC40*f24+fC20*f22;
  Double_t b10=fC10*f00, b12=fC10*f20+fC41*f24+fC21*f22;
  Double_t b20=fC20*f00, b22=fC20*f20+fC42*f24+fC22*f22;
  Double_t b30=fC30*f00, b32=fC30*f20+fC43*f24+fC32*f22;
  Double_t b40=fC40*f00, b42=fC40*f20+fC44*f24+fC42*f22;

  //a = f*b = f*C*ft
  Double_t a00=f00*b00, a02=f00*b02, a22=f20*b02+f24*b42+f22*b22;

  // *** Double_t dy2=fCyy;

  //F*C*Ft = C + (a + b + bt)
  fC00 += a00 + 2*b00;
  fC10 += b10;
  fC20 += a02+b20+b02;
  fC30 += b30;
  fC40 += b40;
  fC21 += b12;
  fC32 += b32;
  fC22 += a22 + 2*b22;
  fC42 += b42; 

  // *** fCyy+=dy2*sa*sa*r1*r1/(1.- r1*r1);
  // *** fCzz+=d2y*sa*sa*fT*fT/(1.- r1*r1);

  return 1;
}

void AliTPCtrack::ResetCovariance() {
  //------------------------------------------------------------------
  //This function makes a track forget its history :)  
  //------------------------------------------------------------------

  fC00*=10.;
  fC10=0.;  fC11*=10.;
  fC20=0.;  fC21=0.;  fC22*=10.;
  fC30=0.;  fC31=0.;  fC32=0.;  fC33*=10.;
  fC40=0.;  fC41=0.;  fC42=0.;  fC43=0.;  fC44*=10.;

}

////////////////////////////////////////////////////////////////////////
Double_t AliTPCtrack::Phi() const {
//
//
//
  Double_t phi =  TMath::ASin(GetSnp()) + fAlpha;
  if (phi<0) phi+=2*TMath::Pi();
  if (phi>=2*TMath::Pi()) phi-=2*TMath::Pi();
  return phi;
}
////////////////////////////////////////////////////////////////////////
Commit	Line	Data
73042f01	1	/**************************************************************************
	2	* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
	3	* *
	4	* Author: The ALICE Off-line Project. *
	5	* Contributors are mentioned in the code where appropriate. *
	6	* *
	7	* Permission to use, copy, modify and distribute this software and its *
	8	* documentation strictly for non-commercial purposes is hereby granted *
	9	* without fee, provided that the above copyright notice appears in all *
	10	* copies and that both the copyright notice and this permission notice *
	11	* appear in the supporting documentation. The authors make no claims *
	12	* about the suitability of this software for any purpose. It is *
	13	* provided "as is" without express or implied warranty. *
	14	**************************************************************************/
	15
803d1ab0	16	/* $Id$ */
0938c7d3	17
73042f01	18	//-----------------------------------------------------------------
73042f01	19	// Implementation of the TPC track class
7c27857f	20	// This class is used by the AliTPCtracker class
7c27857f	21	// Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
73042f01	22	//-----------------------------------------------------------------
73042f01	23
19364939	24	#include <Riostream.h>
b19a0509	25
73042f01	26	#include "AliTPCtrack.h"
7c27857f	27	#include "AliCluster.h"
9c9d2487	28	#include "AliBarrelTrack.h"
83d73500	29	#include "AliESDtrack.h"
73042f01	30
73042f01	31	ClassImp(AliTPCtrack)
b9de75e1	32
e3f7105e	33	//_________________________________________________________________________
	34	AliTPCtrack::AliTPCtrack(): AliKalmanTrack()
	35	{
	36	fX = fP0 = fP1 = fP2 = fP3 = fP3 = fP4 = 0.0;
	37	fAlpha = fdEdx = 0.0;
9c9d2487	38	fNWrong = fNRotation = fNumber = 0; // [SR, 01.04.2003]
e3f7105e	39	}
e3f7105e	40
73042f01	41	//_________________________________________________________________________
73042f01	42	AliTPCtrack::AliTPCtrack(UInt_t index, const Double_t xx[5],
b19a0509	43	const Double_t cc[15], Double_t xref, Double_t alpha) : AliKalmanTrack() {
73042f01	44	//-----------------------------------------------------------------
	45	// This is the main track constructor.
	46	//-----------------------------------------------------------------
73042f01	47	fX=xref;
be9c5115	48	fAlpha=alpha;
	49	if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
	50	if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
	51	fdEdx=0.;
73042f01	52
b19a0509	53	fP0=xx[0]; fP1=xx[1]; fP2=xx[2]; fP3=xx[3]; fP4=xx[4];
73042f01	54
b19a0509	55	fC00=cc[0];
	56	fC10=cc[1]; fC11=cc[2];
	57	fC20=cc[3]; fC21=cc[4]; fC22=cc[5];
	58	fC30=cc[6]; fC31=cc[7]; fC32=cc[8]; fC33=cc[9];
	59	fC40=cc[10]; fC41=cc[11]; fC42=cc[12]; fC43=cc[13]; fC44=cc[14];
73042f01	60
be9c5115	61	fIndex[0]=index;
be9c5115	62	SetNumberOfClusters(1);
b9de75e1	63
	64	}
	65
	66	//_____________________________________________________________________________
e1a65e92	67	AliTPCtrack::AliTPCtrack(const AliKalmanTrack& t,Double_t alpha) :
e1a65e92	68	AliKalmanTrack(t) {
b9de75e1	69	//-----------------------------------------------------------------
	70	// Conversion AliKalmanTrack -> AliTPCtrack.
	71	//-----------------------------------------------------------------
b9de75e1	72	SetChi2(0.);
b9de75e1	73	SetNumberOfClusters(0);
b9de75e1	74
	75	fdEdx = 0.;
	76	fAlpha = alpha;
	77	if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
	78	else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
	79
	80	//Conversion of the track parameters
	81	Double_t x,p[5]; t.GetExternalParameters(x,p);
	82	fX=x; x=GetConvConst();
	83	fP0=p[0];
	84	fP1=p[1];
	85	fP3=p[3];
	86	fP4=p[4]/x;
	87	fP2=fP4*fX - p[2];
	88
	89	//Conversion of the covariance matrix
	90	Double_t c[15]; t.GetExternalCovariance(c);
	91	c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x;
	92
	93	Double_t c22=fXfXc[14] - 2fXc[12] + c[5];
	94	Double_t c32=fX*c[13] - c[8];
	95	Double_t c20=fXc[10] - c[3], c21=fXc[11] - c[4], c42=fX*c[14] - c[12];
	96
	97	fC00=c[0 ];
	98	fC10=c[1 ]; fC11=c[2 ];
	99	fC20=c20; fC21=c21; fC22=c22;
	100	fC30=c[6 ]; fC31=c[7 ]; fC32=c32; fC33=c[9 ];
	101	fC40=c[10]; fC41=c[11]; fC42=c42; fC43=c[13]; fC44=c[14];
	102
73042f01	103	}
73042f01	104
83d73500	105	//_____________________________________________________________________________
	106	AliTPCtrack::AliTPCtrack(const AliESDtrack& t) : AliKalmanTrack() {
	107	//-----------------------------------------------------------------
	108	// Conversion AliESDtrack -> AliTPCtrack.
	109	//-----------------------------------------------------------------
	110	SetNumberOfClusters(t.GetTPCclusters(fIndex));
	111	SetLabel(t.GetLabel());
	112	SetMass(t.GetMass());
	113
	114	fdEdx = t.GetTPCsignal();
	115	fAlpha = t.GetAlpha();
	116	if (fAlpha < -TMath::Pi()) fAlpha += 2*TMath::Pi();
	117	else if (fAlpha >= TMath::Pi()) fAlpha -= 2*TMath::Pi();
	118
	119	//Conversion of the track parameters
	120	Double_t x,p[5]; t.GetExternalParameters(x,p);
	121	fX=x; x=GetConvConst();
	122	fP0=p[0];
	123	fP1=p[1];
	124	fP3=p[3];
	125	fP4=p[4]/x;
	126	fP2=fP4*fX - p[2];
	127
	128	//Conversion of the covariance matrix
	129	Double_t c[15]; t.GetExternalCovariance(c);
	130	c[10]/=x; c[11]/=x; c[12]/=x; c[13]/=x; c[14]/=x*x;
	131
	132	Double_t c22=fXfXc[14] - 2fXc[12] + c[5];
	133	Double_t c32=fX*c[13] - c[8];
	134	Double_t c20=fXc[10] - c[3], c21=fXc[11] - c[4], c42=fX*c[14] - c[12];
	135
	136	fC00=c[0 ];
	137	fC10=c[1 ]; fC11=c[2 ];
	138	fC20=c20; fC21=c21; fC22=c22;
	139	fC30=c[6 ]; fC31=c[7 ]; fC32=c32; fC33=c[9 ];
	140	fC40=c[10]; fC41=c[11]; fC42=c42; fC43=c[13]; fC44=c[14];
	141
0798b21e	142	if ((t.GetStatus()&AliESDtrack::kTIME) == 0) return;
83d73500	143	StartTimeIntegral();
	144	Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
	145	SetIntegratedLength(t.GetIntegratedLength());
	146	}
	147
73042f01	148	//_____________________________________________________________________________
b19a0509	149	AliTPCtrack::AliTPCtrack(const AliTPCtrack& t) : AliKalmanTrack(t) {
73042f01	150	//-----------------------------------------------------------------
	151	// This is a track copy constructor.
	152	//-----------------------------------------------------------------
be9c5115	153	fX=t.fX;
be9c5115	154	fAlpha=t.fAlpha;
73042f01	155	fdEdx=t.fdEdx;
73042f01	156
be9c5115	157	fP0=t.fP0; fP1=t.fP1; fP2=t.fP2; fP3=t.fP3; fP4=t.fP4;
	158
	159	fC00=t.fC00;
	160	fC10=t.fC10; fC11=t.fC11;
	161	fC20=t.fC20; fC21=t.fC21; fC22=t.fC22;
	162	fC30=t.fC30; fC31=t.fC31; fC32=t.fC32; fC33=t.fC33;
	163	fC40=t.fC40; fC41=t.fC41; fC42=t.fC42; fC43=t.fC43; fC44=t.fC44;
	164
	165	Int_t n=GetNumberOfClusters();
	166	for (Int_t i=0; i<n; i++) fIndex[i]=t.fIndex[i];
	167	}
9c9d2487	168	//_____________________________________________________________________________
	169
	170	void AliTPCtrack::GetBarrelTrack(AliBarrelTrack *track) {
	171	//
	172	// Create a Barrel Track out of this track
	173	// Current track is propagated to the reference plane
	174	// by the tracker
	175	//
	176	// [SR, 01.04.2003]
	177
	178	if (!track) return;
	179	Double_t xr, vec[5], cov[15];
	180
	181	track->SetLabel(GetLabel());
	182	track->SetX(fX, fAlpha);
	183	track->SetNClusters(GetNumberOfClusters(), GetChi2());
2b5dc063	184	Double_t times[10];
	185	GetIntegratedTimes(times);
	186	track->SetTime(times, GetIntegratedLength());
9c9d2487	187
2b5dc063	188	track->SetMass(GetMass());
2b5dc063	189	track->SetdEdX(GetdEdx());
9c9d2487	190
	191	track->SetNWrongClusters(fNWrong);
	192	track->SetNRotate(fNRotation);
be9c5115	193
9c9d2487	194	GetExternalParameters(xr, vec);
	195	track->SetStateVector(vec);
	196
	197	GetExternalCovariance(cov);
	198	track->SetCovarianceMatrix(cov);
	199
	200	}
be9c5115	201	//_____________________________________________________________________________
	202	Int_t AliTPCtrack::Compare(const TObject *o) const {
	203	//-----------------------------------------------------------------
	204	// This function compares tracks according to the their curvature
	205	//-----------------------------------------------------------------
	206	AliTPCtrack t=(AliTPCtrack)o;
024a7fe9	207	//Double_t co=TMath::Abs(t->Get1Pt());
	208	//Double_t c =TMath::Abs(Get1Pt());
	209	Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
	210	Double_t c =GetSigmaY2()*GetSigmaZ2();
be9c5115	211	if (c>co) return 1;
	212	else if (c<co) return -1;
	213	return 0;
	214	}
	215
	216	//_____________________________________________________________________________
	217	void AliTPCtrack::GetExternalCovariance(Double_t cc[15]) const {
	218	//-------------------------------------------------------------------------
	219	// This function returns an external representation of the covriance matrix.
	220	// (See comments in AliTPCtrack.h about external track representation)
	221	//-------------------------------------------------------------------------
9b280d80	222	Double_t a=GetConvConst();
be9c5115	223
b9de75e1	224	Double_t c22=fXfXfC44-2fXfC42+fC22;
	225	Double_t c32=fX*fC43-fC32;
	226	Double_t c20=fXfC40-fC20, c21=fXfC41-fC21, c42=fX*fC44-fC42;
be9c5115	227
	228	cc[0 ]=fC00;
	229	cc[1 ]=fC10; cc[2 ]=fC11;
	230	cc[3 ]=c20; cc[4 ]=c21; cc[5 ]=c22;
b9de75e1	231	cc[6 ]=fC30; cc[7 ]=fC31; cc[8 ]=c32; cc[9 ]=fC33;
b9de75e1	232	cc[10]=fC40a; cc[11]=fC41a; cc[12]=c42a; cc[13]=fC43a; cc[14]=fC44aa;
be9c5115	233
	234	}
	235
	236	//_____________________________________________________________________________
	237	Double_t AliTPCtrack::GetPredictedChi2(const AliCluster *c) const
	238	{
	239	//-----------------------------------------------------------------
	240	// This function calculates a predicted chi2 increment.
	241	//-----------------------------------------------------------------
	242	Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
	243	r00+=fC00; r01+=fC10; r11+=fC11;
	244
	245	Double_t det=r00r11 - r01r01;
	246	if (TMath::Abs(det) < 1.e-10) {
	247	Int_t n=GetNumberOfClusters();
	248	if (n>4) cerr<<n<<" AliKalmanTrack warning: Singular matrix !\n";
	249	return 1e10;
	250	}
	251	Double_t tmp=r00; r00=r11; r11=tmp; r01=-r01;
	252
	253	Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1;
	254
	255	return (dyr00dy + 2r01dydz + dzr11*dz)/det;
73042f01	256	}
73042f01	257
c630aafd	258	Double_t AliTPCtrack::GetYat(Double_t xk) const {
	259	//-----------------------------------------------------------------
	260	// This function calculates the Y-coordinate of a track at the plane x=xk.
	261	//-----------------------------------------------------------------
	262	Double_t c1=fP4fX - fP2, r1=TMath::Sqrt(1.- c1c1);
	263	Double_t c2=fP4xk - fP2, r2=TMath::Sqrt(1.- c2c2);
	264	return fP0 + (xk-fX)*(c1+c2)/(r1+r2);
	265	}
	266
73042f01	267	//_____________________________________________________________________________
7f6ddf58	268	Int_t AliTPCtrack::PropagateTo(Double_t xk,Double_t x0,Double_t rho) {
73042f01	269	//-----------------------------------------------------------------
	270	// This function propagates a track to a reference plane x=xk.
	271	//-----------------------------------------------------------------
1627d1c4	272	if (TMath::Abs(fP4*xk - fP2) >= 0.9) {
	273	// Int_t n=GetNumberOfClusters();
	274	//if (n>4) cerr<<n<<" AliTPCtrack warning: Propagation failed !\n";
73042f01	275	return 0;
73042f01	276	}
e3f7105e	277
	278	// old position for time [SR, GSI 17.02.2003]
	279	Double_t oldX = fX;
	280	Double_t oldY = fP0;
	281	Double_t oldZ = fP1;
	282	//
73042f01	283
b19a0509	284	Double_t x1=fX, x2=x1+(xk-x1), dx=x2-x1, y1=fP0, z1=fP1;
b9de75e1	285	Double_t c1=fP4x1 - fP2, r1=sqrt(1.- c1c1);
b9de75e1	286	Double_t c2=fP4x2 - fP2, r2=sqrt(1.- c2c2);
73042f01	287
b19a0509	288	fP0 += dx*(c1+c2)/(r1+r2);
b9de75e1	289	fP1 += dx(c1+c2)/(c1r2 + c2r1)fP3;
73042f01	290
	291	//f = F - 1
	292	Double_t rr=r1+r2, cc=c1+c2, xx=x1+x2;
b19a0509	293	Double_t f02=-dx(2rr + cc(c1/r1 + c2/r2))/(rrrr);
b9de75e1	294	Double_t f04= dx(rrxx + cc(c1x1/r1+c2x2/r2))/(rrrr);
73042f01	295	Double_t cr=c1r2+c2r1;
b9de75e1	296	Double_t f12=-dxfP3(2cr + cc(c2c1/r1-r1 + c1c2/r2-r2))/(cr*cr);
	297	Double_t f13= dx*cc/cr;
	298	Double_t f14=dxfP3(crxx-cc(r1x2-c2c1x1/r1+r2x1-c1c2x2/r2))/(cr*cr);
73042f01	299
73042f01	300	//b = C*ft
b9de75e1	301	Double_t b00=f02fC20 + f04fC40, b01=f12fC20 + f14fC40 + f13*fC30;
	302	Double_t b10=f02fC21 + f04fC41, b11=f12fC21 + f14fC41 + f13*fC31;
	303	Double_t b20=f02fC22 + f04fC42, b21=f12fC22 + f14fC42 + f13*fC32;
	304	Double_t b30=f02fC32 + f04fC43, b31=f12fC32 + f14fC43 + f13*fC33;
	305	Double_t b40=f02fC42 + f04fC44, b41=f12fC42 + f14fC44 + f13*fC43;
73042f01	306
73042f01	307	//a = fb = fC*ft
b9de75e1	308	Double_t a00=f02b20+f04b40,a01=f02b21+f04b41,a11=f12b21+f14b41+f13*b31;
73042f01	309
73042f01	310	//FCFt = C + (a + b + bt)
b19a0509	311	fC00 += a00 + 2*b00;
	312	fC10 += a01 + b01 + b10;
	313	fC20 += b20;
	314	fC30 += b30;
	315	fC40 += b40;
	316	fC11 += a11 + 2*b11;
	317	fC21 += b21;
	318	fC31 += b31;
	319	fC41 += b41;
73042f01	320
	321	fX=x2;
	322
	323	//Multiple scattering******************
b19a0509	324	Double_t d=sqrt((x1-fX)(x1-fX)+(y1-fP0)(y1-fP0)+(z1-fP1)*(z1-fP1));
be9c5115	325	Double_t p2=(1.+ GetTgl()GetTgl())/(Get1Pt()Get1Pt());
7f6ddf58	326	Double_t beta2=p2/(p2 + GetMass()*GetMass());
024a7fe9	327	//Double_t theta2=14.114.1/(beta2p21e6)d/x0*rho;
024a7fe9	328	Double_t theta2=1.0259e-61010/20/(beta2p2)d*rho;
73042f01	329
b9de75e1	330	Double_t ey=fP4*fX - fP2, ez=fP3;
b9de75e1	331	Double_t xz=fP4ez, zz1=ezez+1, xy=fP2+ey;
73042f01	332
b19a0509	333	fC22 += (2eyezezfP2+1-eyey+ezez+fP2fP2ezez)theta2;
b9de75e1	334	fC32 += ezzz1xy*theta2;
	335	fC33 += zz1zz1theta2;
	336	fC42 += xzezxy*theta2;
	337	fC43 += xzzz1theta2;
	338	fC44 += xzxztheta2;
73042f01	339
	340	//Energy losses************************
	341	Double_t dE=0.153e-3/beta2(log(5940beta2/(1-beta2)) - beta2)drho;
	342	if (x1 < x2) dE=-dE;
b9de75e1	343	cc=fP4;
7f6ddf58	344	fP4=(1.- sqrt(p2+GetMass()GetMass())/p2*dE);
b9de75e1	345	fP2+=fX*(fP4-cc);
73042f01	346
e3f7105e	347	// Integrated Time [SR, GSI, 17.02.2003]
	348	if (IsStartedTimeIntegral()) {
	349	Double_t l2 = (fX-oldX)(fX-oldX)+(fP0-oldY)(fP0-oldY)+(fP1-oldZ)*(fP1-oldZ);
	350	AddTimeStep(TMath::Sqrt(l2));
	351	}
	352	//
	353
73042f01	354	return 1;
	355	}
	356
	357	//_____________________________________________________________________________
7f6ddf58	358	Int_t AliTPCtrack::PropagateToVertex(Double_t x0,Double_t rho)
73042f01	359	{
	360	//-----------------------------------------------------------------
	361	// This function propagates tracks to the "vertex".
	362	//-----------------------------------------------------------------
b9de75e1	363	Double_t c=fP4*fX - fP2;
b9de75e1	364	Double_t tgf=-fP2/(fP4fP0 + sqrt(1-cc));
73042f01	365	Double_t snf=tgf/sqrt(1.+ tgf*tgf);
b9de75e1	366	Double_t xv=(fP2+snf)/fP4;
7f6ddf58	367	return PropagateTo(xv,x0,rho);
73042f01	368	}
	369
	370	//_____________________________________________________________________________
be9c5115	371	Int_t AliTPCtrack::Update(const AliCluster *c, Double_t chisq, UInt_t index) {
73042f01	372	//-----------------------------------------------------------------
	373	// This function associates a cluster with this track.
	374	//-----------------------------------------------------------------
9c9d2487	375
	376	// update the number of wrong SR[20.03.2003]
	377	Int_t absLabel = TMath::Abs(GetLabel());
	378	if ( (c->GetLabel(0) != absLabel) &&
	379	(c->GetLabel(0) != absLabel) &&
	380	(c->GetLabel(0) != absLabel)) fNWrong++;
	381	//
	382
73042f01	383	Double_t r00=c->GetSigmaY2(), r01=0., r11=c->GetSigmaZ2();
b19a0509	384	r00+=fC00; r01+=fC10; r11+=fC11;
73042f01	385	Double_t det=r00r11 - r01r01;
	386	Double_t tmp=r00; r00=r11/det; r11=tmp/det; r01=-r01/det;
	387
b19a0509	388	Double_t k00=fC00r00+fC10r01, k01=fC00r01+fC10r11;
	389	Double_t k10=fC10r00+fC11r01, k11=fC10r01+fC11r11;
	390	Double_t k20=fC20r00+fC21r01, k21=fC20r01+fC21r11;
	391	Double_t k30=fC30r00+fC31r01, k31=fC30r01+fC31r11;
	392	Double_t k40=fC40r00+fC41r01, k41=fC40r01+fC41r11;
73042f01	393
b19a0509	394	Double_t dy=c->GetY() - fP0, dz=c->GetZ() - fP1;
b9de75e1	395	Double_t cur=fP4 + k40dy + k41dz, eta=fP2 + k20dy + k21dz;
1627d1c4	396	if (TMath::Abs(cur*fX-eta) >= 0.9) {
	397	// Int_t n=GetNumberOfClusters();
	398	//if (n>4) cerr<<n<<" AliTPCtrack warning: Filtering failed !\n";
be9c5115	399	return 0;
73042f01	400	}
73042f01	401
b19a0509	402	fP0 += k00dy + k01dz;
	403	fP1 += k10dy + k11dz;
	404	fP2 = eta;
b9de75e1	405	fP3 += k30dy + k31dz;
b9de75e1	406	fP4 = cur;
73042f01	407
b19a0509	408	Double_t c01=fC10, c02=fC20, c03=fC30, c04=fC40;
b19a0509	409	Double_t c12=fC21, c13=fC31, c14=fC41;
73042f01	410
b19a0509	411	fC00-=k00fC00+k01fC10; fC10-=k00c01+k01fC11;
	412	fC20-=k00c02+k01c12; fC30-=k00c03+k01c13;
	413	fC40-=k00c04+k01c14;
73042f01	414
b19a0509	415	fC11-=k10c01+k11fC11;
	416	fC21-=k10c02+k11c12; fC31-=k10c03+k11c13;
	417	fC41-=k10c04+k11c14;
73042f01	418
b19a0509	419	fC22-=k20c02+k21c12; fC32-=k20c03+k21c13;
b19a0509	420	fC42-=k20c04+k21c14;
73042f01	421
b19a0509	422	fC33-=k30c03+k31c13;
b9de75e1	423	fC43-=k40c03+k41c13;
73042f01	424
b19a0509	425	fC44-=k40c04+k41c14;
73042f01	426
be9c5115	427	Int_t n=GetNumberOfClusters();
	428	fIndex[n]=index;
	429	SetNumberOfClusters(n+1);
	430	SetChi2(GetChi2()+chisq);
	431
	432	return 1;
73042f01	433	}
	434
	435	//_____________________________________________________________________________
	436	Int_t AliTPCtrack::Rotate(Double_t alpha)
	437	{
	438	//-----------------------------------------------------------------
	439	// This function rotates this track.
	440	//-----------------------------------------------------------------
9c9d2487	441
	442	if (alpha != 0) fNRotation++; // [SR, 01.04.2003]
	443
73042f01	444	fAlpha += alpha;
be9c5115	445	if (fAlpha<-TMath::Pi()) fAlpha += 2*TMath::Pi();
be9c5115	446	if (fAlpha>=TMath::Pi()) fAlpha -= 2*TMath::Pi();
73042f01	447
b19a0509	448	Double_t x1=fX, y1=fP0;
73042f01	449	Double_t ca=cos(alpha), sa=sin(alpha);
b9de75e1	450	Double_t r1=fP4*fX - fP2;
73042f01	451
73042f01	452	fX = x1ca + y1sa;
b19a0509	453	fP0=-x1sa + y1ca;
b9de75e1	454	fP2=fP2ca + (fP4y1 + sqrt(1.- r1r1))sa;
73042f01	455
b9de75e1	456	Double_t r2=fP4*fX - fP2;
73042f01	457	if (TMath::Abs(r2) >= 0.99999) {
be9c5115	458	Int_t n=GetNumberOfClusters();
be9c5115	459	if (n>4) cerr<<n<<" AliTPCtrack warning: Rotation failed !\n";
73042f01	460	return 0;
	461	}
	462
b9de75e1	463	Double_t y0=fP0 + sqrt(1.- r2*r2)/fP4;
b9de75e1	464	if ((fP0-y0)*fP4 >= 0.) {
be9c5115	465	Int_t n=GetNumberOfClusters();
be9c5115	466	if (n>4) cerr<<n<<" AliTPCtrack warning: Rotation failed !!!\n";
73042f01	467	return 0;
	468	}
	469
	470	//f = F - 1
b9de75e1	471	Double_t f00=ca-1, f24=(y1 - r1x1/sqrt(1.- r1r1))*sa,
b9de75e1	472	f20=fP4sa, f22=(ca + sar1/sqrt(1.- r1*r1))-1;
73042f01	473
73042f01	474	//b = C*ft
b9de75e1	475	Double_t b00=fC00f00, b02=fC00f20+fC40f24+fC20f22;
	476	Double_t b10=fC10f00, b12=fC10f20+fC41f24+fC21f22;
	477	Double_t b20=fC20f00, b22=fC20f20+fC42f24+fC22f22;
	478	Double_t b30=fC30f00, b32=fC30f20+fC43f24+fC32f22;
	479	Double_t b40=fC40f00, b42=fC40f20+fC44f24+fC42f22;
73042f01	480
73042f01	481	//a = fb = fC*ft
b9de75e1	482	Double_t a00=f00b00, a02=f00b02, a22=f20b02+f24b42+f22*b22;
73042f01	483
	484	// *** Double_t dy2=fCyy;
	485
	486	//FCFt = C + (a + b + bt)
b19a0509	487	fC00 += a00 + 2*b00;
	488	fC10 += b10;
	489	fC20 += a02+b20+b02;
	490	fC30 += b30;
	491	fC40 += b40;
	492	fC21 += b12;
	493	fC32 += b32;
	494	fC22 += a22 + 2*b22;
	495	fC42 += b42;
73042f01	496
	497	// *** fCyy+=dy2sasar1r1/(1.- r1*r1);
	498	// *** fCzz+=d2ysasafTfT/(1.- r1*r1);
	499
	500	return 1;
	501	}
	502
b9de75e1	503	void AliTPCtrack::ResetCovariance() {
	504	//------------------------------------------------------------------
	505	//This function makes a track forget its history :)
	506	//------------------------------------------------------------------
	507
	508	fC00*=10.;
	509	fC10=0.; fC11*=10.;
	510	fC20=0.; fC21=0.; fC22*=10.;
	511	fC30=0.; fC31=0.; fC32=0.; fC33*=10.;
	512	fC40=0.; fC41=0.; fC42=0.; fC43=0.; fC44*=10.;
	513
73042f01	514	}
77e58468	515
	516	////////////////////////////////////////////////////////////////////////
	517	Double_t AliTPCtrack::Phi() const {
7c27857f	518	//
	519	//
	520	//
77e58468	521	Double_t phi = TMath::ASin(GetSnp()) + fAlpha;
	522	if (phi<0) phi+=2*TMath::Pi();
	523	if (phi>=2TMath::Pi()) phi-=2TMath::Pi();
	524	return phi;
	525	}
	526	////////////////////////////////////////////////////////////////////////
	527