[u/mrichter/AliRoot.git] / HMPID / AliHMPIDtrack.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.                  *
 **************************************************************************/

#include "AliESDtrack.h" 
#include "AliTracker.h" 
#include "AliHMPIDtrack.h" 

ClassImp(AliHMPIDtrack)

//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
AliHMPIDtrack::AliHMPIDtrack():AliKalmanTrack()
{
  //
  // def. ctor
  //
}                                
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
AliHMPIDtrack::AliHMPIDtrack(const AliHMPIDtrack& t):AliKalmanTrack(t)
{
  //
  // cctor.
  //
 }                                
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
AliHMPIDtrack::AliHMPIDtrack(const AliESDtrack& t):AliKalmanTrack()
{
  //
  // Constructor from AliESDtrack
  //
  SetLabel(t.GetLabel());
  SetChi2(0.);
  SetMass(t.GetMass());

  Set(t.GetX(),t.GetAlpha(),t.GetParameter(),t.GetCovariance());

  if ((t.GetStatus()&AliESDtrack::kTIME) == 0) return;
  StartTimeIntegral();
  Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
  SetIntegratedLength(t.GetIntegratedLength());
}              
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
AliHMPIDtrack& AliHMPIDtrack::operator=(const AliHMPIDtrack &/*source*/)
{
  // ass. op.
  
  return *this;
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Bool_t AliHMPIDtrack::PropagateTo(Double_t xk, Double_t xx0, Double_t xrho)
{
  //
  // Propagates this track to a reference plane defined by "xk" [cm] 
  // correcting for the mean crossed material.
  // Arguments:
  // "xx0"  - thickness/rad.length [units of the radiation length] 
  // "xrho" - thickness*density    [g/cm^2] 
  //  Returns: kTRUE if the track propagates to plane, else kFALSE
 
  if (xk == GetX()) {
    return kTRUE;
  }
  Double_t b[3]; GetBxByBz(b);
  if (!AliExternalTrackParam::PropagateToBxByBz(xk,b)) {
    return kFALSE;
  }
  if (!AliExternalTrackParam::CorrectForMeanMaterial(xx0,xrho,GetMass())) { 
    return kFALSE;
  }
  return kTRUE;            
}//PropagateTo()  
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Bool_t AliHMPIDtrack::Rotate(Double_t alpha, Bool_t absolute)
{
  //
  // Rotates track parameters in R*phi plane
  // if absolute rotation alpha is in global system
  // otherwise alpha rotation is relative to the current rotation angle
  //  

  if (absolute) {
    alpha -= GetAlpha();
  }
 

  return AliExternalTrackParam::Rotate(GetAlpha()+alpha);

}   
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++  
Int_t AliHMPIDtrack::GetProlongation(Double_t xk, Double_t &y, Double_t &z)
{
  //
  // Find a prolongation at given x
  // Return 0 if it does not exist
  //  

  Double_t bz = GetBz();

  if (!AliExternalTrackParam::GetYAt(xk,bz,y)) {
    return 0;
  }
  if (!AliExternalTrackParam::GetZAt(xk,bz,z)) {
    return 0;
  }

  return 1;  

}
 
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Bool_t   AliHMPIDtrack::PropagateToR(Double_t r,Double_t step)
{
  //
  // Propagate track to the radial position
  // Rotation always connected to the last track position
  //

  Double_t xyz0[3];
  Double_t xyz1[3];
  Double_t y;
  Double_t z; 

  Double_t radius = TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
  // Direction +-
  Double_t dir    = (radius > r) ? -1.0 : 1.0;   

  for (Double_t x = radius+dir*step; dir*x < dir*r; x += dir*step) {

    GetXYZ(xyz0);	
    Double_t alpha = TMath::ATan2(xyz0[1],xyz0[0]);
    Rotate(alpha,kTRUE);
    GetXYZ(xyz0);	
    if (!GetProlongation(x,y,z)) return kFALSE;
    xyz1[0] = x * TMath::Cos(alpha) + y * TMath::Sin(alpha); 
    xyz1[1] = x * TMath::Sin(alpha) - y * TMath::Cos(alpha);
    xyz1[2] = z;
    Double_t param[7];
    AliTracker::MeanMaterialBudget(xyz0,xyz1,param);
    if (param[1] <= 0) {
      param[1] = 100000000;
    }
    PropagateTo(x,param[1],param[0]*param[4]);

  } 

  GetXYZ(xyz0);	
  Double_t alpha = TMath::ATan2(xyz0[1],xyz0[0]);
  Rotate(alpha,kTRUE);
  GetXYZ(xyz0);	
  if (!GetProlongation(r,y,z)) return kFALSE;
  xyz1[0] = r * TMath::Cos(alpha) + y * TMath::Sin(alpha); 
  xyz1[1] = r * TMath::Sin(alpha) - y * TMath::Cos(alpha);
  xyz1[2] = z;
  Double_t param[7];
  AliTracker::MeanMaterialBudget(xyz0,xyz1,param);

  if (param[1] <= 0) {
    param[1] = 100000000;
  }
 
  return PropagateTo(r,param[1],param[0]*param[4]);
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Double_t AliHMPIDtrack::GetPredictedChi2(const AliCluster3D *c) const {
  //
  // Arguments: AliCluster3D
  // Returns:   Chi2 of track for the cluster
  Double_t      p[3]={c->GetX(),       c->GetY(),       c->GetZ()};
  Double_t  covyz[3]={c->GetSigmaY2(), c->GetSigmaYZ(), c->GetSigmaZ2()};
  Double_t covxyz[3]={c->GetSigmaX2(), c->GetSigmaXY(), c->GetSigmaXZ()};
  return AliExternalTrackParam::GetPredictedChi2(p, covyz, covxyz);
}//GetPredictedChi2()
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Bool_t AliHMPIDtrack::PropagateTo(const AliCluster3D *c) {
  //
  // Arguments: AliCluster3D
  // Returns: kTRUE if the track propagates to the plane of the cluster
  Double_t      oldX=GetX(),   oldY=GetY(), oldZ=GetZ();
  Double_t      p[3]={c->GetX(), c->GetY(), c->GetZ()};
  Double_t  covyz[3]={c->GetSigmaY2(), c->GetSigmaYZ(), c->GetSigmaZ2()};
  Double_t covxyz[3]={c->GetSigmaX2(), c->GetSigmaXY(), c->GetSigmaXZ()};
  Double_t bz=-GetBz();
    
  if(!AliExternalTrackParam::PropagateTo(p, covyz, covxyz, bz)) return kFALSE;
  if(IsStartedTimeIntegral()) 
    {
      Double_t d = TMath::Sqrt((GetX()-oldX)*(GetX()-oldX) + (GetY()-oldY)*(GetY()-oldY) + (GetZ()-oldZ)*(GetZ()-oldZ));
      if (GetX()<oldX) d=-d;
      AddTimeStep(d);
    }
  return kTRUE;
}//PropagateTo()
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Bool_t AliHMPIDtrack::Intersect(Double_t pnt[3], Double_t norm[3]) const {
  //+++++++++++++++++++++++++++++++++++++++++    
  // Origin: K. Shileev (Kirill.Shileev@cern.ch)
  // Finds point of intersection (if exists) of the helix with the plane. 
  // Stores result in fX and fP.   
  // Arguments: planePoint,planeNorm - the plane defined by any plane's point 
  // and vector, normal to the plane
  // Returns: kTrue if helix intersects the plane, kFALSE otherwise.
  //+++++++++++++++++++++++++++++++++++++++++    
  Double_t x0[3]; GetXYZ(x0); //get track position in MARS
  
  //estimates initial helix length up to plane
  Double_t s=(pnt[0]-x0[0])*norm[0] + (pnt[1]-x0[1])*norm[1] + (pnt[2]-x0[2])*norm[2];
  Double_t dist=99999,distPrev=dist;
  Double_t p[3],x[3]; 
  while(TMath::Abs(dist)>0.00001){
    //calculates helix at the distance s from x0 ALONG the helix
    Propagate(s,x,p);
    //distance between current helix position and plane
    dist=(x[0]-pnt[0])*norm[0]+(x[1]-pnt[1])*norm[1]+(x[2]-pnt[2])*norm[2];  
    if(TMath::Abs(dist) >= TMath::Abs(distPrev)) {return kFALSE;}
    distPrev=dist;
    s-=dist;
  }
  //on exit pnt is intersection point,norm is track vector at that point, 
  //all in MARS
  for (Int_t i=0; i<3; i++) {pnt[i]=x[i]; norm[i]=p[i];}
  return kTRUE;
}//Intersect()
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
void AliHMPIDtrack::Propagate(Double_t len, Double_t x[3],Double_t p[3]) const {
  //+++++++++++++++++++++++++++++++++++++++++    
  // Origin: K. Shileev (Kirill.Shileev@cern.ch)
  // Extrapolate track along simple helix in magnetic field
  // Arguments: len -distance alogn helix, [cm]
  //            bz  - mag field, [kGaus]   
  // Returns: x and p contain extrapolated positon and momentum  
  // The momentum returned for straight-line tracks is meaningless !
  //+++++++++++++++++++++++++++++++++++++++++    
  GetXYZ(x);    
  Double_t bField[3];
  TGeoGlobalMagField::Instance()->Field(x,bField);
  Double_t bz = -bField[2];
  if (OneOverPt() < kAlmost0 || TMath::Abs(bz) < kAlmost0Field ){ //straight-line tracks
     Double_t unit[3]; GetDirection(unit);
     x[0]+=unit[0]*len;   
     x[1]+=unit[1]*len;   
     x[2]+=unit[2]*len;

     p[0]=unit[0]/kAlmost0;   
     p[1]=unit[1]/kAlmost0;   
     p[2]=unit[2]/kAlmost0;   
  } else {
     GetPxPyPz(p);
     Double_t pp=GetP();
     Double_t a = -kB2C*bz*GetSign(); ////////// what is kB2C
     Double_t rho = a/pp;
     x[0] += p[0]*TMath::Sin(rho*len)/a - p[1]*(1-TMath::Cos(rho*len))/a;
     x[1] += p[1]*TMath::Sin(rho*len)/a + p[0]*(1-TMath::Cos(rho*len))/a;
     x[2] += p[2]*len/pp;
     Double_t p0=p[0];
     p[0] = p0  *TMath::Cos(rho*len) - p[1]*TMath::Sin(rho*len);
     p[1] = p[1]*TMath::Cos(rho*len) + p0  *TMath::Sin(rho*len);
  }
}//Propagate()
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Bool_t AliHMPIDtrack::Update(const AliHMPIDCluster *pClu, Double_t /*chisq*/, Int_t /*index*/)
{
  //
  // Arguments: AliCluster3D, chi sq, and clu index
  // Returns: kTRUE if the track parameters are successfully updated
  Double_t p[2]={pClu->GetY(), pClu->GetZ()};
  Double_t cov[3]={pClu->GetSigmaY2(), 0., pClu->GetSigmaZ2()};
  if (!AliExternalTrackParam::Update(p,cov)) return kFALSE;

  /*
  AliTracker::FillResiduals(this,p,cov,pClu->GetVolumeId());

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

}//Update()
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Commit	Line	Data
83253968	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
	16	#include "AliESDtrack.h"
	17	#include "AliTracker.h"
	18	#include "AliHMPIDtrack.h"
	19
	20	ClassImp(AliHMPIDtrack)
	21
	22	//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	23	AliHMPIDtrack::AliHMPIDtrack():AliKalmanTrack()
	24	{
	25	//
	26	// def. ctor
	27	//
	28	}
	29	//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	30	AliHMPIDtrack::AliHMPIDtrack(const AliHMPIDtrack& t):AliKalmanTrack(t)
	31	{
	32	//
	33	// cctor.
	34	//
	35	}
	36	//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	37	AliHMPIDtrack::AliHMPIDtrack(const AliESDtrack& t):AliKalmanTrack()
	38	{
	39	//
	40	// Constructor from AliESDtrack
	41	//
	42	SetLabel(t.GetLabel());
	43	SetChi2(0.);
	44	SetMass(t.GetMass());
	45
	46	Set(t.GetX(),t.GetAlpha(),t.GetParameter(),t.GetCovariance());
	47
	48	if ((t.GetStatus()&AliESDtrack::kTIME) == 0) return;
	49	StartTimeIntegral();
	50	Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
	51	SetIntegratedLength(t.GetIntegratedLength());
	52	}
	53	//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	54	AliHMPIDtrack& AliHMPIDtrack::operator=(const AliHMPIDtrack &/source/)
	55	{
	56	// ass. op.
	57
	58	return *this;
	59	}
	60	//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	61	Bool_t AliHMPIDtrack::PropagateTo(Double_t xk, Double_t xx0, Double_t xrho)
	62	{
	63	//
	64	// Propagates this track to a reference plane defined by "xk" [cm]
65	// correcting for the mean crossed material.
66	// Arguments:
67	// "xx0" - thickness/rad.length [units of the radiation length]
68	// "xrho" - thickness*density [g/cm^2]
69	// Returns: kTRUE if the track propagates to plane, else kFALSE
70
71	if (xk == GetX()) {
72	return kTRUE;
73	}
87a6d94b	74	Double_t b[3]; GetBxByBz(b);
87a6d94b	75	if (!AliExternalTrackParam::PropagateToBxByBz(xk,b)) {
83253968	76	return kFALSE;
	77	}
	78	if (!AliExternalTrackParam::CorrectForMeanMaterial(xx0,xrho,GetMass())) {
	79	return kFALSE;
	80	}
	81	return kTRUE;
	82	}//PropagateTo()
	83	//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	84	Bool_t AliHMPIDtrack::Rotate(Double_t alpha, Bool_t absolute)
	85	{
	86	//
	87	// Rotates track parameters in R*phi plane
	88	// if absolute rotation alpha is in global system
	89	// otherwise alpha rotation is relative to the current rotation angle
	90	//
	91
	92	if (absolute) {
	93	alpha -= GetAlpha();
	94	}
	95
	96
	97	return AliExternalTrackParam::Rotate(GetAlpha()+alpha);
	98
	99	}
	100	//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	101	Int_t AliHMPIDtrack::GetProlongation(Double_t xk, Double_t &y, Double_t &z)
	102	{
	103	//
	104	// Find a prolongation at given x
	105	// Return 0 if it does not exist
	106	//
	107
87a6d94b	108	Double_t bz = GetBz();
83253968	109
	110	if (!AliExternalTrackParam::GetYAt(xk,bz,y)) {
	111	return 0;
	112	}
	113	if (!AliExternalTrackParam::GetZAt(xk,bz,z)) {
	114	return 0;
	115	}
	116
	117	return 1;
	118
	119	}
	120
	121	//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
496c71b0	122	Bool_t AliHMPIDtrack::PropagateToR(Double_t r,Double_t step)
83253968	123	{
	124	//
	125	// Propagate track to the radial position
	126	// Rotation always connected to the last track position
	127	//
	128
	129	Double_t xyz0[3];
	130	Double_t xyz1[3];
	131	Double_t y;
	132	Double_t z;
	133
	134	Double_t radius = TMath::Sqrt(GetX()GetX() + GetY()GetY());
	135	// Direction +-
	136	Double_t dir = (radius > r) ? -1.0 : 1.0;
	137
	138	for (Double_t x = radius+dirstep; dirx < dirr; x += dirstep) {
	139
	140	GetXYZ(xyz0);
	141	Double_t alpha = TMath::ATan2(xyz0[1],xyz0[0]);
	142	Rotate(alpha,kTRUE);
	143	GetXYZ(xyz0);
6d256146	144	if (!GetProlongation(x,y,z)) return kFALSE;
83253968	145	xyz1[0] = x * TMath::Cos(alpha) + y * TMath::Sin(alpha);
	146	xyz1[1] = x * TMath::Sin(alpha) - y * TMath::Cos(alpha);
	147	xyz1[2] = z;
	148	Double_t param[7];
	149	AliTracker::MeanMaterialBudget(xyz0,xyz1,param);
	150	if (param[1] <= 0) {
	151	param[1] = 100000000;
	152	}
	153	PropagateTo(x,param[1],param[0]*param[4]);
	154
	155	}
	156
	157	GetXYZ(xyz0);
	158	Double_t alpha = TMath::ATan2(xyz0[1],xyz0[0]);
	159	Rotate(alpha,kTRUE);
	160	GetXYZ(xyz0);
6d256146	161	if (!GetProlongation(r,y,z)) return kFALSE;
83253968	162	xyz1[0] = r * TMath::Cos(alpha) + y * TMath::Sin(alpha);
	163	xyz1[1] = r * TMath::Sin(alpha) - y * TMath::Cos(alpha);
	164	xyz1[2] = z;
	165	Double_t param[7];
	166	AliTracker::MeanMaterialBudget(xyz0,xyz1,param);
	167
	168	if (param[1] <= 0) {
	169	param[1] = 100000000;
	170	}
496c71b0	171
496c71b0	172	return PropagateTo(r,param[1],param[0]*param[4]);
83253968	173	}
	174	//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	175	Double_t AliHMPIDtrack::GetPredictedChi2(const AliCluster3D *c) const {
	176	//
	177	// Arguments: AliCluster3D
	178	// Returns: Chi2 of track for the cluster
	179	Double_t p[3]={c->GetX(), c->GetY(), c->GetZ()};
	180	Double_t covyz[3]={c->GetSigmaY2(), c->GetSigmaYZ(), c->GetSigmaZ2()};
	181	Double_t covxyz[3]={c->GetSigmaX2(), c->GetSigmaXY(), c->GetSigmaXZ()};
	182	return AliExternalTrackParam::GetPredictedChi2(p, covyz, covxyz);
	183	}//GetPredictedChi2()
	184	//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	185	Bool_t AliHMPIDtrack::PropagateTo(const AliCluster3D *c) {
	186	//
	187	// Arguments: AliCluster3D
	188	// Returns: kTRUE if the track propagates to the plane of the cluster
	189	Double_t oldX=GetX(), oldY=GetY(), oldZ=GetZ();
	190	Double_t p[3]={c->GetX(), c->GetY(), c->GetZ()};
	191	Double_t covyz[3]={c->GetSigmaY2(), c->GetSigmaYZ(), c->GetSigmaZ2()};
	192	Double_t covxyz[3]={c->GetSigmaX2(), c->GetSigmaXY(), c->GetSigmaXZ()};
5b147198	193	Double_t bz=-GetBz();
87a6d94b	194
83253968	195	if(!AliExternalTrackParam::PropagateTo(p, covyz, covxyz, bz)) return kFALSE;
	196	if(IsStartedTimeIntegral())
	197	{
	198	Double_t d = TMath::Sqrt((GetX()-oldX)(GetX()-oldX) + (GetY()-oldY)(GetY()-oldY) + (GetZ()-oldZ)*(GetZ()-oldZ));
	199	if (GetX()<oldX) d=-d;
	200	AddTimeStep(d);
87a6d94b	201	}
83253968	202	return kTRUE;
83253968	203	}//PropagateTo()
97a4d538	204	//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
97a4d538	205	Bool_t AliHMPIDtrack::Intersect(Double_t pnt[3], Double_t norm[3]) const {
83253968	206	//+++++++++++++++++++++++++++++++++++++++++
	207	// Origin: K. Shileev (Kirill.Shileev@cern.ch)
	208	// Finds point of intersection (if exists) of the helix with the plane.
	209	// Stores result in fX and fP.
	210	// Arguments: planePoint,planeNorm - the plane defined by any plane's point
	211	// and vector, normal to the plane
	212	// Returns: kTrue if helix intersects the plane, kFALSE otherwise.
	213	//+++++++++++++++++++++++++++++++++++++++++
	214	Double_t x0[3]; GetXYZ(x0); //get track position in MARS
83253968	215
	216	//estimates initial helix length up to plane
	217	Double_t s=(pnt[0]-x0[0])norm[0] + (pnt[1]-x0[1])norm[1] + (pnt[2]-x0[2])*norm[2];
	218	Double_t dist=99999,distPrev=dist;
97a4d538	219	Double_t p[3],x[3];
83253968	220	while(TMath::Abs(dist)>0.00001){
83253968	221	//calculates helix at the distance s from x0 ALONG the helix
97a4d538	222	Propagate(s,x,p);
83253968	223	//distance between current helix position and plane
	224	dist=(x[0]-pnt[0])norm[0]+(x[1]-pnt[1])norm[1]+(x[2]-pnt[2])*norm[2];
	225	if(TMath::Abs(dist) >= TMath::Abs(distPrev)) {return kFALSE;}
	226	distPrev=dist;
	227	s-=dist;
	228	}
	229	//on exit pnt is intersection point,norm is track vector at that point,
	230	//all in MARS
	231	for (Int_t i=0; i<3; i++) {pnt[i]=x[i]; norm[i]=p[i];}
	232	return kTRUE;
	233	}//Intersect()
	234	//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
97a4d538	235	void AliHMPIDtrack::Propagate(Double_t len, Double_t x[3],Double_t p[3]) const {
83253968	236	//+++++++++++++++++++++++++++++++++++++++++
	237	// Origin: K. Shileev (Kirill.Shileev@cern.ch)
	238	// Extrapolate track along simple helix in magnetic field
	239	// Arguments: len -distance alogn helix, [cm]
	240	// bz - mag field, [kGaus]
	241	// Returns: x and p contain extrapolated positon and momentum
	242	// The momentum returned for straight-line tracks is meaningless !
	243	//+++++++++++++++++++++++++++++++++++++++++
	244	GetXYZ(x);
97a4d538	245	Double_t bField[3];
97a4d538	246	TGeoGlobalMagField::Instance()->Field(x,bField);
5b147198	247	Double_t bz = -bField[2];
83253968	248	if (OneOverPt() < kAlmost0 \|\| TMath::Abs(bz) < kAlmost0Field ){ //straight-line tracks
	249	Double_t unit[3]; GetDirection(unit);
	250	x[0]+=unit[0]*len;
	251	x[1]+=unit[1]*len;
	252	x[2]+=unit[2]*len;
	253
	254	p[0]=unit[0]/kAlmost0;
	255	p[1]=unit[1]/kAlmost0;
	256	p[2]=unit[2]/kAlmost0;
	257	} else {
	258	GetPxPyPz(p);
	259	Double_t pp=GetP();
	260	Double_t a = -kB2CbzGetSign(); ////////// what is kB2C
	261	Double_t rho = a/pp;
	262	x[0] += p[0]TMath::Sin(rholen)/a - p[1](1-TMath::Cos(rholen))/a;
	263	x[1] += p[1]TMath::Sin(rholen)/a + p[0](1-TMath::Cos(rholen))/a;
	264	x[2] += p[2]*len/pp;
	265	Double_t p0=p[0];
	266	p[0] = p0 TMath::Cos(rholen) - p[1]TMath::Sin(rholen);
	267	p[1] = p[1]TMath::Cos(rholen) + p0 TMath::Sin(rholen);
	268	}
	269	}//Propagate()
	270	//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
ee2f3539	271	Bool_t AliHMPIDtrack::Update(const AliHMPIDCluster pClu, Double_t /chisq/, Int_t /index*/)
496c71b0	272	{
	273	//
	274	// Arguments: AliCluster3D, chi sq, and clu index
	275	// Returns: kTRUE if the track parameters are successfully updated
	276	Double_t p[2]={pClu->GetY(), pClu->GetZ()};
	277	Double_t cov[3]={pClu->GetSigmaY2(), 0., pClu->GetSigmaZ2()};
	278	if (!AliExternalTrackParam::Update(p,cov)) return kFALSE;
	279
	280	/*
	281	AliTracker::FillResiduals(this,p,cov,pClu->GetVolumeId());
	282
	283	Int_t n=GetNumberOfClusters();
	284	fIndex[n]=index;
	285	SetNumberOfClusters(n+1);
	286	SetChi2(GetChi2()+chisq);
	287	*/
	288	return kTRUE;
	289
	290	}//Update()
	291	//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++