[u/mrichter/AliRoot.git] / HLT / hough / AliL3HoughTrack.cxx

//$Id$

// Author: Anders Vestbo <mailto:vestbo@fi.uib.no>
//*-- Copyright &copy ASV 

#include <math.h>

#include "AliL3Logging.h"
#include "AliL3Transform.h"
#include "AliL3Defs.h"
#include "AliL3HoughTrack.h"

//_____________________________________________________________
// AliL3HoughTrack
//
// Track class for Hough tracklets

ClassImp(AliL3HoughTrack)


AliL3HoughTrack::AliL3HoughTrack()
{
  //Constructor
  
  fWeight = 0;
  fMinDist=0;
  fTransform = new AliL3Transform();
  fDLine = 0;
  fPsiLine = 0;
  fIsHelix = true;
  fEtaIndex = -1;
}


AliL3HoughTrack::~AliL3HoughTrack()
{
  //Destructor
  if(fTransform)
    delete fTransform;
}

void AliL3HoughTrack::Set(AliL3Track *track)
{
  
  AliL3HoughTrack *tpt = (AliL3HoughTrack*)track;
  SetTrackParameters(tpt->GetKappa(),tpt->GetPhi0(),tpt->GetWeight());
  SetEtaIndex(tpt->GetEtaIndex());
  SetEta(tpt->GetEta());
  SetPsi(tpt->GetPsi());
  SetCenterX(tpt->GetCenterX());
  SetCenterY(tpt->GetCenterY());
  SetFirstPoint(tpt->GetFirstPointX(),tpt->GetFirstPointY(),tpt->GetFirstPointZ());
  SetLastPoint(tpt->GetLastPointX(),tpt->GetLastPointY(),tpt->GetLastPointZ());
  SetCharge(tpt->GetCharge());
  SetRowRange(tpt->GetFirstRow(),tpt->GetLastRow());
  SetSlice(tpt->GetSlice());
  return;

  fWeight = tpt->GetWeight();
  fDLine = tpt->GetDLine();
  fPsiLine = tpt->GetPsiLine();
  SetNHits(tpt->GetWeight());
  SetRowRange(tpt->GetFirstRow(),tpt->GetLastRow());
  fIsHelix = false;


}

Int_t AliL3HoughTrack::Compare(const AliL3Track *tpt) const
{
  AliL3HoughTrack *track = (AliL3HoughTrack*)tpt;
  if(track->GetWeight() < GetWeight()) return 1;
  if(track->GetWeight() > GetWeight()) return -1;
  return 0;
}

void AliL3HoughTrack::SetEta(Double_t f)
{
  //Set eta, and calculate fTanl, which is the tan of dipangle

  fEta = f;
  Double_t theta = 2*atan(exp(-1.*fEta));
  Double_t dipangle = Pi/2 - theta;
  Double_t tgl = tan(dipangle);
  SetTgl(tgl);
}

void AliL3HoughTrack::CalculateHelix()
{
  return;
}

void AliL3HoughTrack::UpdateToFirstRow()
{
  //Update the track parameters to the point where track cross
  //its first padrow.
  
  //Get the crossing point with the first padrow:
  Float_t xyz[3];
  if(!GetCrossingPoint(GetFirstRow(),xyz))
    LOG(AliL3Log::kWarning,"AliL3HoughTrack::UpdateToFirstRow()","Track parameters")
      <<AliL3Log::kDec<<"Track does not cross padrow "<<GetFirstRow()<<" centerx "
      <<GetCenterX()<<" centery "<<GetCenterY()<<" Radius "<<GetRadius()<<" tgl "<<GetTgl()<<ENDLOG;
  
  //printf("Track with eta %f tgl %f crosses at x %f y %f z %f on padrow %d\n",GetEta(),GetTgl(),xyz[0],xyz[1],xyz[2],GetFirstRow());
  //printf("Before: first %f %f %f tgl %f center %f %f charge %d\n",GetFirstPointX(),GetFirstPointY(),GetFirstPointZ(),GetTgl(),GetCenterX(),GetCenterY(),GetCharge());
  
  Double_t radius = sqrt(xyz[0]*xyz[0] + xyz[1]*xyz[1]);

  //Get the track parameters
  
  /*
    Double_t x0    = GetR0() * cos(GetPhi0()) ;
    Double_t y0    = GetR0() * sin(GetPhi0()) ;
  */
  Double_t rc    = GetRadius();//fabs(GetPt()) / ( BFACT * BField )  ;
  Double_t tPhi0 = GetPsi() + GetCharge() * 0.5 * pi / fabs(GetCharge()) ;
  Double_t xc    = GetCenterX();//x0 - rc * cos(tPhi0) ;
  Double_t yc    = GetCenterY();//y0 - rc * sin(tPhi0) ;
  
  //Check helix and cylinder intersect
  Double_t fac1 = xc*xc + yc*yc ;
  Double_t sfac = sqrt( fac1 ) ;
  
  if ( fabs(sfac-rc) > radius || fabs(sfac+rc) < radius ) {
    LOG(AliL3Log::kError,"AliL3HoughTrack::UpdateToFirstRow","Tracks")<<AliL3Log::kDec<<
      "Track does not intersect"<<ENDLOG;
    return;
  }
  
  //Find intersection
  Double_t fac2   = ( radius*radius + fac1 - rc*rc) / (2.00 * radius * sfac ) ;
  Double_t phi    = atan2(yc,xc) + GetCharge()*acos(fac2) ;
  Double_t td     = atan2(radius*sin(phi) - yc,radius*cos(phi) - xc) ;
  
  //Intersection in z
  if ( td < 0 ) td = td + 2. * pi ;
  Double_t deltat = fmod((-GetCharge()*td + GetCharge()*tPhi0),2*pi) ;
  if ( deltat < 0.      ) deltat += 2. * pi ;
  if ( deltat > 2.*pi ) deltat -= 2. * pi ;
  Double_t z = GetZ0() + rc * GetTgl() * deltat ;
  
  
  Double_t xExtra = radius * cos(phi) ;
  Double_t yExtra = radius * sin(phi) ;
  
  Double_t tPhi = atan2(yExtra-yc,xExtra-xc);
  
  //if ( tPhi < 0 ) tPhi += 2. * M_PI ;
  
  Double_t tPsi = tPhi - GetCharge() * 0.5 * pi / fabs(GetCharge()) ;
  if ( tPsi > 2. * pi ) tPsi -= 2. * pi ;
  if ( tPsi < 0.        ) tPsi += 2. * pi ;
  
  //And finally, update the track parameters
  SetR0(radius);
  SetPhi0(phi);
  SetZ0(z);
  SetPsi(tPsi);
  SetFirstPoint(xyz[0],xyz[1],z);
  //printf("After: first %f %f %f tgl %f center %f %f charge %d\n",GetFirstPointX(),GetFirstPointY(),GetFirstPointZ(),GetTgl(),GetCenterX(),GetCenterY(),GetCharge());
  
  //printf("First point set %f %f %f\n",xyz[0],xyz[1],z);
  
  //Also, set the coordinates of the point where track crosses last padrow:
  GetCrossingPoint(GetLastRow(),xyz);
  SetLastPoint(xyz[0],xyz[1],xyz[2]);
  //printf("last point %f %f %f\n",xyz[0],xyz[1],xyz[2]);
}

void AliL3HoughTrack::SetTrackParameters(Double_t kappa,Double_t phi,Int_t weight)
{

  fWeight = weight;
  fMinDist = 100000;
  SetKappa(kappa);
  SetPhi0(phi);
  Double_t pt = fabs(BFACT*BField/kappa);
  SetPt(pt);
  Double_t radius = 1/fabs(kappa);
  SetRadius(radius);
  SetFirstPoint(0,0,0);
  SetPsi(phi); //Psi = Phi when first point is vertex
  SetR0(0);
  Double_t charge = -1.*kappa;
  SetCharge((Int_t)copysign(1.,charge));
  
  Double_t trackPhi0 = GetPsi() + charge*0.5*Pi/fabs(charge);
  Double_t xc = GetFirstPointX() - GetRadius() * cos(trackPhi0) ;
  Double_t yc = GetFirstPointY() - GetRadius() * sin(trackPhi0) ;
  SetCenterX(xc);
  SetCenterY(yc);
  fIsHelix = true;
  
}

void AliL3HoughTrack::SetLineParameters(Double_t psi,Double_t D,Int_t weight,Int_t *rowrange,Int_t ref_row)
{
  //Initialize a track piece, not yet a track
  //Used in case of straight line transformation

  //Transform line parameters to coordinate system of slice:
  
  D = D + fTransform->Row2X(ref_row)*cos(psi);

  fDLine = D;
  fPsiLine = psi;
  fWeight = weight;
  SetNHits(weight);
  SetRowRange(rowrange[0],rowrange[1]);
  fIsHelix = false;

}

void AliL3HoughTrack::SetBestMCid(Int_t mcid,Double_t min_dist)
{
  
  if(min_dist < fMinDist)
    {
      fMinDist = min_dist;
      SetMCid(mcid);
    }
  
}

void AliL3HoughTrack::GetLineCrossingPoint(Int_t padrow,Double_t *xy)
{
  

  if(fIsHelix)
    {
      printf("AliL3HoughTrack::GetLineCrossingPoint : Track is not a line\n");
      return;
    }

  Double_t xhit = fTransform->Row2X(padrow);
  Double_t a = -1/tan(fPsiLine);
  Double_t b = fDLine/sin(fPsiLine);
  
  Double_t yhit = a*xhit + b;
  xy[0] = xhit;
  xy[1] = yhit;

}

/*
Double_t AliL3HoughTrack::GetCrossingAngle(Int_t padrow)
{
  //Calculate the crossing angle between track and given padrow.

  if(!fIsHelix)
    {
      printf("AliL3HoughTrack::GetCrossingAngle : Track is not a helix\n");
      return 0;
    }

  if(!IsLocal())
    {
      printf("Track is not given in local coordinates\n");
      return 0;
    }

  Float_t xyz[3];
  if(!GetCrossingPoint(padrow,xyz))
    printf("AliL3HoughTrack::GetCrossingPoint : Track does not cross line!!\n");
  
  
  //Convert center of curvature to local coordinates:
  //Float_t xyz_coc[3] = {GetCenterX(),GetCenterY(),0};
  //fTransform->Global2Local(xyz_coc,slice);
  
  //Take the dot product of the tangent vector of the track, and
  //vector perpendicular to the padrow.
  
  Double_t tangent[2];
  //tangent[1] = (xyz[0] - xyz_coc[0])/GetRadius();
  //tangent[0] = -1.*(xyz[1] - xyz_coc[1])/GetRadius();
  tangent[1] = (xyz[0] - GetCenterX())/GetRadius();
  tangent[0] = -1.*(xyz[1] - GetCenterY())/GetRadius();

  Double_t perp_padrow[2] = {1,0}; //locally in slice

  Double_t cos_beta = fabs(tangent[0]*perp_padrow[0] + tangent[1]*perp_padrow[1]);
  return acos(cos_beta);
  
}

Bool_t AliL3HoughTrack::GetCrossingPoint(Int_t padrow,Float_t *xyz)
{
  //Assumes the track is given in local coordinates

  if(!fIsHelix)
    {
      printf("AliL3HoughTrack::GetCrossingPoint : Track is not a helix\n");
      return 0;
    }
    

  if(!IsLocal())
    {
      printf("GetCrossingPoint: Track is given on global coordinates\n");
      return false;
    }
  
  Double_t xHit = fTransform->Row2X(padrow);

  //xyz[0] = fTransform->Row2X(padrow);
  xyz[0] = xHit;
  Double_t aa = (xHit - GetCenterX())*(xHit - GetCenterX());
  Double_t r2 = GetRadius()*GetRadius();
  if(aa > r2)
    return false;

  Double_t aa2 = sqrt(r2 - aa);
  Double_t y1 = GetCenterY() + aa2;
  Double_t y2 = GetCenterY() - aa2;
  xyz[1] = y1;
  if(fabs(y2) < fabs(y1)) xyz[1] = y2;
  xyz[2] = 0; //only consider transverse plane
  
  return true;
}


Bool_t AliL3HoughTrack::GetCrossingPoint(Int_t slice,Int_t padrow,Float_t *xyz)
{
  //Calculate the crossing point in transverse plane of this track and given 
  //padrow (y = a*x + b). Point is given in local coordinates in slice.
  //Assumes the track is given in global coordinates.

  if(!fIsHelix)
    {
      printf("AliL3HoughTrack::GetCrossingPoint : Track is not a helix\n");
      return 0;
    }

  
  if(IsLocal())
    {
      printf("GetCrossingPoint: Track is given in local coordintes!!!\n");
      return false;
    }

  Double_t padrowradii = fTransform->Row2X(padrow);


  Float_t rotation_angle = (slice*20)*ToRad;
  
  Float_t cs,sn;
  cs = cos(rotation_angle);
  sn = sin(rotation_angle);

  Double_t a = -1.*cs/sn;
  Double_t b = padrowradii/sn;

  Double_t ycPrime = GetCenterY() - b ;
  Double_t aa = ( 1. + a * a ) ;
  Double_t bb = -2. * ( GetCenterX() + a * ycPrime ) ;
  Double_t cc = ( GetCenterX() * GetCenterX() + ycPrime * ycPrime - GetRadius() * GetRadius() ) ;

  Double_t racine = bb * bb - 4. * aa * cc ;
  if ( racine < 0 ) return false ;
  Double_t rootRacine = sqrt(racine) ;
  
  Double_t oneOverA = 1./aa;
//
//   First solution
//
   Double_t x1 = 0.5 * oneOverA * ( -1. * bb + rootRacine ) ; 
   Double_t y1 = a * x1 + b ;
   Double_t r1 = sqrt(x1*x1+y1*y1);
//
//   Second solution
//
   Double_t x2 = 0.5 * oneOverA * ( -1. * bb - rootRacine ) ; 
   Double_t y2 = a * x2 + b ;
   Double_t r2 = sqrt(x2*x2+y2*y2);
//
//    Choose close to (0,0) 
//
   Double_t xHit ;
   Double_t yHit ;
   if ( r1 < r2 ) {
      xHit = x1 ;
      yHit = y1 ;
   }
   else {
      xHit = x2 ;
      yHit = y2 ;
   }
  
   xyz[0] = xHit;
   xyz[1] = yHit;
   xyz[2] = 0;
   
   fTransform->Global2Local(xyz,slice);
   
   return true;
}
*/
Commit	Line	Data
b1886074	1	//$Id$
	2
	3	// Author: Anders Vestbo <mailto:vestbo@fi.uib.no>
	4	//*-- Copyright &copy ASV
d712b5b8	5
	6	#include <math.h>
	7
	8	#include "AliL3Logging.h"
	9	#include "AliL3Transform.h"
	10	#include "AliL3Defs.h"
	11	#include "AliL3HoughTrack.h"
	12
b1886074	13	//_____________________________________________________________
	14	// AliL3HoughTrack
	15	//
	16	// Track class for Hough tracklets
	17
d712b5b8	18	ClassImp(AliL3HoughTrack)
	19
	20
	21	AliL3HoughTrack::AliL3HoughTrack()
	22	{
	23	//Constructor
	24
	25	fWeight = 0;
	26	fMinDist=0;
	27	fTransform = new AliL3Transform();
	28	fDLine = 0;
	29	fPsiLine = 0;
	30	fIsHelix = true;
	31	fEtaIndex = -1;
	32	}
	33
	34
	35	AliL3HoughTrack::~AliL3HoughTrack()
	36	{
	37	//Destructor
	38	if(fTransform)
	39	delete fTransform;
	40	}
	41
	42	void AliL3HoughTrack::Set(AliL3Track *track)
	43	{
	44
	45	AliL3HoughTrack tpt = (AliL3HoughTrack)track;
	46	SetTrackParameters(tpt->GetKappa(),tpt->GetPhi0(),tpt->GetWeight());
	47	SetEtaIndex(tpt->GetEtaIndex());
	48	SetEta(tpt->GetEta());
	49	SetPsi(tpt->GetPsi());
	50	SetCenterX(tpt->GetCenterX());
	51	SetCenterY(tpt->GetCenterY());
	52	SetFirstPoint(tpt->GetFirstPointX(),tpt->GetFirstPointY(),tpt->GetFirstPointZ());
	53	SetLastPoint(tpt->GetLastPointX(),tpt->GetLastPointY(),tpt->GetLastPointZ());
	54	SetCharge(tpt->GetCharge());
	55	SetRowRange(tpt->GetFirstRow(),tpt->GetLastRow());
b1886074	56	SetSlice(tpt->GetSlice());
d712b5b8	57	return;
	58
	59	fWeight = tpt->GetWeight();
	60	fDLine = tpt->GetDLine();
	61	fPsiLine = tpt->GetPsiLine();
	62	SetNHits(tpt->GetWeight());
	63	SetRowRange(tpt->GetFirstRow(),tpt->GetLastRow());
	64	fIsHelix = false;
	65
	66
	67	}
	68
	69	Int_t AliL3HoughTrack::Compare(const AliL3Track *tpt) const
	70	{
	71	AliL3HoughTrack track = (AliL3HoughTrack)tpt;
	72	if(track->GetWeight() < GetWeight()) return 1;
	73	if(track->GetWeight() > GetWeight()) return -1;
	74	return 0;
	75	}
	76
	77	void AliL3HoughTrack::SetEta(Double_t f)
	78	{
b1886074	79	//Set eta, and calculate fTanl, which is the tan of dipangle
b1886074	80
d712b5b8	81	fEta = f;
d712b5b8	82	Double_t theta = 2atan(exp(-1.fEta));
8b007a2d	83	Double_t dipangle = Pi/2 - theta;
8b007a2d	84	Double_t tgl = tan(dipangle);
d712b5b8	85	SetTgl(tgl);
	86	}
	87
	88	void AliL3HoughTrack::CalculateHelix()
	89	{
	90	return;
	91	}
	92
	93	void AliL3HoughTrack::UpdateToFirstRow()
	94	{
	95	//Update the track parameters to the point where track cross
	96	//its first padrow.
	97
	98	//Get the crossing point with the first padrow:
	99	Float_t xyz[3];
	100	if(!GetCrossingPoint(GetFirstRow(),xyz))
	101	LOG(AliL3Log::kWarning,"AliL3HoughTrack::UpdateToFirstRow()","Track parameters")
	102	<<AliL3Log::kDec<<"Track does not cross padrow "<<GetFirstRow()<<" centerx "
	103	<<GetCenterX()<<" centery "<<GetCenterY()<<" Radius "<<GetRadius()<<" tgl "<<GetTgl()<<ENDLOG;
	104
8b007a2d	105	//printf("Track with eta %f tgl %f crosses at x %f y %f z %f on padrow %d\n",GetEta(),GetTgl(),xyz[0],xyz[1],xyz[2],GetFirstRow());
	106	//printf("Before: first %f %f %f tgl %f center %f %f charge %d\n",GetFirstPointX(),GetFirstPointY(),GetFirstPointZ(),GetTgl(),GetCenterX(),GetCenterY(),GetCharge());
	107
d712b5b8	108	Double_t radius = sqrt(xyz[0]xyz[0] + xyz[1]xyz[1]);
	109
	110	//Get the track parameters
b1886074	111
	112	/*
	113	Double_t x0 = GetR0() * cos(GetPhi0()) ;
	114	Double_t y0 = GetR0() * sin(GetPhi0()) ;
	115	*/
	116	Double_t rc = GetRadius();//fabs(GetPt()) / ( BFACT * BField ) ;
d712b5b8	117	Double_t tPhi0 = GetPsi() + GetCharge() * 0.5 * pi / fabs(GetCharge()) ;
b1886074	118	Double_t xc = GetCenterX();//x0 - rc * cos(tPhi0) ;
b1886074	119	Double_t yc = GetCenterY();//y0 - rc * sin(tPhi0) ;
d712b5b8	120
	121	//Check helix and cylinder intersect
	122	Double_t fac1 = xcxc + ycyc ;
	123	Double_t sfac = sqrt( fac1 ) ;
b1886074	124
d712b5b8	125	if ( fabs(sfac-rc) > radius \|\| fabs(sfac+rc) < radius ) {
	126	LOG(AliL3Log::kError,"AliL3HoughTrack::UpdateToFirstRow","Tracks")<<AliL3Log::kDec<<
	127	"Track does not intersect"<<ENDLOG;
	128	return;
	129	}
	130
	131	//Find intersection
	132	Double_t fac2 = ( radiusradius + fac1 - rcrc) / (2.00 * radius * sfac ) ;
	133	Double_t phi = atan2(yc,xc) + GetCharge()*acos(fac2) ;
	134	Double_t td = atan2(radiussin(phi) - yc,radiuscos(phi) - xc) ;
	135
	136	//Intersection in z
	137	if ( td < 0 ) td = td + 2. * pi ;
	138	Double_t deltat = fmod((-GetCharge()td + GetCharge()tPhi0),2*pi) ;
	139	if ( deltat < 0. ) deltat += 2. * pi ;
	140	if ( deltat > 2.pi ) deltat -= 2. pi ;
	141	Double_t z = GetZ0() + rc * GetTgl() * deltat ;
8b007a2d	142
d712b5b8	143
	144	Double_t xExtra = radius * cos(phi) ;
	145	Double_t yExtra = radius * sin(phi) ;
	146
	147	Double_t tPhi = atan2(yExtra-yc,xExtra-xc);
	148
	149	//if ( tPhi < 0 ) tPhi += 2. * M_PI ;
	150
	151	Double_t tPsi = tPhi - GetCharge() * 0.5 * pi / fabs(GetCharge()) ;
	152	if ( tPsi > 2. * pi ) tPsi -= 2. * pi ;
	153	if ( tPsi < 0. ) tPsi += 2. * pi ;
	154
	155	//And finally, update the track parameters
d712b5b8	156	SetR0(radius);
	157	SetPhi0(phi);
	158	SetZ0(z);
	159	SetPsi(tPsi);
	160	SetFirstPoint(xyz[0],xyz[1],z);
8b007a2d	161	//printf("After: first %f %f %f tgl %f center %f %f charge %d\n",GetFirstPointX(),GetFirstPointY(),GetFirstPointZ(),GetTgl(),GetCenterX(),GetCenterY(),GetCharge());
	162
	163	//printf("First point set %f %f %f\n",xyz[0],xyz[1],z);
d712b5b8	164
	165	//Also, set the coordinates of the point where track crosses last padrow:
	166	GetCrossingPoint(GetLastRow(),xyz);
	167	SetLastPoint(xyz[0],xyz[1],xyz[2]);
8b007a2d	168	//printf("last point %f %f %f\n",xyz[0],xyz[1],xyz[2]);
d712b5b8	169	}
	170
	171	void AliL3HoughTrack::SetTrackParameters(Double_t kappa,Double_t phi,Int_t weight)
	172	{
	173
	174	fWeight = weight;
	175	fMinDist = 100000;
	176	SetKappa(kappa);
	177	SetPhi0(phi);
b1886074	178	Double_t pt = fabs(BFACT*BField/kappa);
d712b5b8	179	SetPt(pt);
	180	Double_t radius = 1/fabs(kappa);
	181	SetRadius(radius);
	182	SetFirstPoint(0,0,0);
8b007a2d	183	SetPsi(phi); //Psi = Phi when first point is vertex
8b007a2d	184	SetR0(0);
d712b5b8	185	Double_t charge = -1.*kappa;
8b007a2d	186	SetCharge((Int_t)copysign(1.,charge));
	187
	188	Double_t trackPhi0 = GetPsi() + charge0.5Pi/fabs(charge);
	189	Double_t xc = GetFirstPointX() - GetRadius() * cos(trackPhi0) ;
	190	Double_t yc = GetFirstPointY() - GetRadius() * sin(trackPhi0) ;
d712b5b8	191	SetCenterX(xc);
	192	SetCenterY(yc);
	193	fIsHelix = true;
8b007a2d	194
d712b5b8	195	}
	196
	197	void AliL3HoughTrack::SetLineParameters(Double_t psi,Double_t D,Int_t weight,Int_t *rowrange,Int_t ref_row)
	198	{
	199	//Initialize a track piece, not yet a track
	200	//Used in case of straight line transformation
	201
	202	//Transform line parameters to coordinate system of slice:
	203
	204	D = D + fTransform->Row2X(ref_row)*cos(psi);
	205
	206	fDLine = D;
	207	fPsiLine = psi;
	208	fWeight = weight;
	209	SetNHits(weight);
	210	SetRowRange(rowrange[0],rowrange[1]);
	211	fIsHelix = false;
	212
	213	}
	214
	215	void AliL3HoughTrack::SetBestMCid(Int_t mcid,Double_t min_dist)
	216	{
	217
	218	if(min_dist < fMinDist)
	219	{
	220	fMinDist = min_dist;
	221	SetMCid(mcid);
	222	}
	223
	224	}
	225
	226	void AliL3HoughTrack::GetLineCrossingPoint(Int_t padrow,Double_t *xy)
	227	{
	228
	229
	230	if(fIsHelix)
	231	{
	232	printf("AliL3HoughTrack::GetLineCrossingPoint : Track is not a line\n");
	233	return;
	234	}
	235
	236	Double_t xhit = fTransform->Row2X(padrow);
	237	Double_t a = -1/tan(fPsiLine);
	238	Double_t b = fDLine/sin(fPsiLine);
	239
	240	Double_t yhit = a*xhit + b;
	241	xy[0] = xhit;
	242	xy[1] = yhit;
	243
	244	}
	245
	246	/*
	247	Double_t AliL3HoughTrack::GetCrossingAngle(Int_t padrow)
	248	{
	249	//Calculate the crossing angle between track and given padrow.
	250
	251	if(!fIsHelix)
	252	{
	253	printf("AliL3HoughTrack::GetCrossingAngle : Track is not a helix\n");
	254	return 0;
	255	}
	256
	257	if(!IsLocal())
	258	{
259	printf("Track is not given in local coordinates\n");
260	return 0;
261	}
262
263	Float_t xyz[3];
264	if(!GetCrossingPoint(padrow,xyz))
265	printf("AliL3HoughTrack::GetCrossingPoint : Track does not cross line!!\n");
266
267
268	//Convert center of curvature to local coordinates:
269	//Float_t xyz_coc[3] = {GetCenterX(),GetCenterY(),0};
270	//fTransform->Global2Local(xyz_coc,slice);
271
272	//Take the dot product of the tangent vector of the track, and
273	//vector perpendicular to the padrow.
274
275	Double_t tangent[2];
276	//tangent[1] = (xyz[0] - xyz_coc[0])/GetRadius();
277	//tangent[0] = -1.*(xyz[1] - xyz_coc[1])/GetRadius();
278	tangent[1] = (xyz[0] - GetCenterX())/GetRadius();
279	tangent[0] = -1.*(xyz[1] - GetCenterY())/GetRadius();
280
281	Double_t perp_padrow[2] = {1,0}; //locally in slice
282
283	Double_t cos_beta = fabs(tangent[0]perp_padrow[0] + tangent[1]perp_padrow[1]);
284	return acos(cos_beta);
285
286	}
287
288	Bool_t AliL3HoughTrack::GetCrossingPoint(Int_t padrow,Float_t *xyz)
289	{
290	//Assumes the track is given in local coordinates
291
292	if(!fIsHelix)
293	{
294	printf("AliL3HoughTrack::GetCrossingPoint : Track is not a helix\n");
295	return 0;
296	}
297
298
299	if(!IsLocal())
300	{
301	printf("GetCrossingPoint: Track is given on global coordinates\n");
302	return false;
303	}
304
305	Double_t xHit = fTransform->Row2X(padrow);
306
307	//xyz[0] = fTransform->Row2X(padrow);
308	xyz[0] = xHit;
309	Double_t aa = (xHit - GetCenterX())*(xHit - GetCenterX());
310	Double_t r2 = GetRadius()*GetRadius();
311	if(aa > r2)
312	return false;
313
314	Double_t aa2 = sqrt(r2 - aa);
315	Double_t y1 = GetCenterY() + aa2;
316	Double_t y2 = GetCenterY() - aa2;
317	xyz[1] = y1;
318	if(fabs(y2) < fabs(y1)) xyz[1] = y2;
319	xyz[2] = 0; //only consider transverse plane
320
321	return true;
322	}
323
324
325	Bool_t AliL3HoughTrack::GetCrossingPoint(Int_t slice,Int_t padrow,Float_t *xyz)
326	{
327	//Calculate the crossing point in transverse plane of this track and given
328	//padrow (y = a*x + b). Point is given in local coordinates in slice.
329	//Assumes the track is given in global coordinates.
330
331	if(!fIsHelix)
332	{
333	printf("AliL3HoughTrack::GetCrossingPoint : Track is not a helix\n");
334	return 0;
335	}
336
337
338	if(IsLocal())
339	{
340	printf("GetCrossingPoint: Track is given in local coordintes!!!\n");
341	return false;
342	}
343
344	Double_t padrowradii = fTransform->Row2X(padrow);
345
346
347	Float_t rotation_angle = (slice20)ToRad;
348
349	Float_t cs,sn;
350	cs = cos(rotation_angle);
351	sn = sin(rotation_angle);
352
353	Double_t a = -1.*cs/sn;
354	Double_t b = padrowradii/sn;
355
356	Double_t ycPrime = GetCenterY() - b ;
357	Double_t aa = ( 1. + a * a ) ;
358	Double_t bb = -2. * ( GetCenterX() + a * ycPrime ) ;
359	Double_t cc = ( GetCenterX() * GetCenterX() + ycPrime * ycPrime - GetRadius() * GetRadius() ) ;
360
361	Double_t racine = bb * bb - 4. * aa * cc ;
362	if ( racine < 0 ) return false ;
363	Double_t rootRacine = sqrt(racine) ;
364
365	Double_t oneOverA = 1./aa;
366	//
367	// First solution
368	//
369	Double_t x1 = 0.5 * oneOverA * ( -1. * bb + rootRacine ) ;
370	Double_t y1 = a * x1 + b ;
371	Double_t r1 = sqrt(x1x1+y1y1);
372	//
373	// Second solution
374	//
375	Double_t x2 = 0.5 * oneOverA * ( -1. * bb - rootRacine ) ;
376	Double_t y2 = a * x2 + b ;
377	Double_t r2 = sqrt(x2x2+y2y2);
378	//
379	// Choose close to (0,0)
380	//
381	Double_t xHit ;
382	Double_t yHit ;
383	if ( r1 < r2 ) {
384	xHit = x1 ;
385	yHit = y1 ;
386	}
387	else {
388	xHit = x2 ;
389	yHit = y2 ;
390	}
391
392	xyz[0] = xHit;
393	xyz[1] = yHit;
394	xyz[2] = 0;
395
396	fTransform->Global2Local(xyz,slice);
397
398	return true;
399	}
400	*/