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

// @(#) $Id$

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

#include "AliHLTStandardIncludes.h"

#include "AliHLTLogging.h"
#include "AliHLTTrack.h"
#include "AliHLTHoughTrack.h"
#include "AliHLTTransform.h"
#include "AliHLTHoughTransformerRow.h"

#if __GNUC__ >= 3
using namespace std;
#endif

/** \class AliHLTHoughTrack
<pre>
//_____________________________________________________________
// AliHLTHoughTrack
//
// Track class for Hough tracklets
//
</pre>
*/

ClassImp(AliHLTHoughTrack)


    AliHLTHoughTrack::AliHLTHoughTrack() : AliHLTTrack()
{
  //Constructor
  
  fWeight = 0;
  fMinDist=0;
  fDLine = 0;
  fPsiLine = 0;
  fIsHelix = true;
  fEtaIndex = -1;
  fEta = 0;
  ComesFromMainVertex(kTRUE);
}

AliHLTHoughTrack::~AliHLTHoughTrack()
{
  //dtor
}

void AliHLTHoughTrack::Set(AliHLTTrack *track)
{
  //Basically copy constructor
  AliHLTHoughTrack *tpt = (AliHLTHoughTrack*)track;
  SetTrackParameters(tpt->GetKappa(),tpt->GetPsi(),tpt->GetWeight());
  SetEtaIndex(tpt->GetEtaIndex());
  SetEta(tpt->GetEta());
  SetTgl(tpt->GetTgl());
  SetPsi(tpt->GetPsi());
  SetPterr(tpt->GetPterr());
  SetTglerr(tpt->GetTglerr());
  SetPsierr(tpt->GetPsierr());
  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());
  SetHits(tpt->GetNHits(),(UInt_t *)tpt->GetHitNumbers());
  SetMCid(tpt->GetMCid());
  SetBinXY(tpt->GetBinX(),tpt->GetBinY(),tpt->GetSizeX(),tpt->GetSizeY());
  SetSector(tpt->GetSector());
  return;

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

Int_t AliHLTHoughTrack::Compare(const AliHLTTrack *tpt) const
{
  //Compare 2 hough tracks according to their weight
  AliHLTHoughTrack *track = (AliHLTHoughTrack*)tpt;
  if(track->GetWeight() < GetWeight()) return 1;
  if(track->GetWeight() > GetWeight()) return -1;
  return 0;
}

void AliHLTHoughTrack::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 = AliHLTTransform::PiHalf() - theta;
  Double_t tgl = tan(dipangle);
  SetTgl(tgl);
}

void AliHLTHoughTrack::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(AliHLTLog::kWarning,"AliHLTHoughTrack::UpdateToFirstRow()","Track parameters")
      <<AliHLTLog::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()) / AliHLTTransform::GetBFieldValue();
  Double_t tPhi0 = GetPsi() + GetCharge() * AliHLTTransform::PiHalf() / abs(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(AliHLTLog::kError,"AliHLTHoughTrack::UpdateToFirstRow","Tracks")<<AliHLTLog::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 + AliHLTTransform::TwoPi();
  Double_t deltat = fmod((-GetCharge()*td + GetCharge()*tPhi0),AliHLTTransform::TwoPi());
  if ( deltat < 0. ) deltat += AliHLTTransform::TwoPi();
  else if ( deltat > AliHLTTransform::TwoPi() ) deltat -= AliHLTTransform::TwoPi();
  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() * AliHLTTransform::PiHalf() / abs(GetCharge()) ;
  if ( tPsi > AliHLTTransform::TwoPi() ) tPsi -= AliHLTTransform::TwoPi() ;
  else if ( tPsi < 0. ) tPsi += AliHLTTransform::TwoPi();
  
  //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 AliHLTHoughTrack::SetTrackParameters(Double_t kappa,Double_t eangle,Int_t weight)
{
  //Set track parameters - sort of ctor
  fWeight = weight;
  fMinDist = 100000;
  SetKappa(kappa);
  Double_t pt = fabs(AliHLTTransform::GetBFieldValue()/kappa);
  SetPt(pt);
  Double_t radius = 1/fabs(kappa);
  SetRadius(radius);
  SetFirstPoint(0,0,0);
  SetPsi(eangle); //Psi = emission angle when first point is vertex
  SetPhi0(0);     //not defined for vertex reference point
  SetR0(0);
  Double_t charge = -1.*kappa;
  SetCharge((Int_t)copysign(1.,charge));
  Double_t trackPhi0 = GetPsi() + charge*0.5*AliHLTTransform::Pi()/fabs(charge);
  Double_t xc = GetFirstPointX() - GetRadius() * cos(trackPhi0) ;
  Double_t yc = GetFirstPointY() - GetRadius() * sin(trackPhi0) ;
  SetCenterX(xc);
  SetCenterY(yc);
  SetNHits(1); //just for the trackarray IO
  fIsHelix = true;
}

void AliHLTHoughTrack::SetTrackParametersRow(Double_t alpha1,Double_t alpha2,Double_t eta,Int_t weight)
{
  //Set track parameters for HoughTransformerRow
  //This includes curvature,emission angle and eta
  Double_t psi = atan((alpha1-alpha2)/(AliHLTHoughTransformerRow::GetBeta1()-AliHLTHoughTransformerRow::GetBeta2()));
  Double_t kappa = 2.0*(alpha1*cos(psi)-AliHLTHoughTransformerRow::GetBeta1()*sin(psi));
  SetTrackParameters(kappa,psi,weight);

  Double_t zovr;
  Double_t etaparam1 = AliHLTHoughTransformerRow::GetEtaCalcParam1();
  Double_t etaparam2 = AliHLTHoughTransformerRow::GetEtaCalcParam2();
  if(eta>0)
    zovr = (etaparam1 - sqrt(etaparam1*etaparam1 - 4.*etaparam2*eta))/(2.*etaparam2);
  else
    zovr = -1.*(etaparam1 - sqrt(etaparam1*etaparam1 + 4.*etaparam2*eta))/(2.*etaparam2);
  Double_t r = sqrt(1.+zovr*zovr);
  Double_t exacteta = 0.5*log((1+zovr/r)/(1-zovr/r));
  SetEta(exacteta);
}

void AliHLTHoughTrack::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(1);
  SetRowRange(rowrange[0],rowrange[1]);
  fIsHelix = false;
}

void AliHLTHoughTrack::SetBestMCid(Int_t mcid,Double_t mindist)
{
  //Finds and set the closest mc label
  if(mindist < fMinDist)
    {
      fMinDist = mindist;
      SetMCid(mcid);
    }
}

void AliHLTHoughTrack::GetLineCrossingPoint(Int_t padrow,Float_t *xy)
{
  //Returns the crossing point of the track with a given padrow
  if(fIsHelix)
    {
      printf("AliHLTHoughTrack::GetLineCrossingPoint : Track is not a line\n");
      return;
    }

  Float_t xhit = AliHLTTransform::Row2X(padrow) - AliHLTTransform::Row2X(GetFirstRow());
  Float_t a = -1/tan(fPsiLine);
  Float_t b = fDLine/sin(fPsiLine);
  Float_t yhit = a*xhit + b;
  xy[0] = xhit;
  xy[1] = yhit;
}
Commit	Line	Data
	1	// @(#) $Id$
	2
	3	// Author: Anders Vestbo <mailto:vestbo@fi.uib.no>
	4	//*-- Copyright &copy ALICE HLT Group
	5
	6	#include "AliHLTStandardIncludes.h"
	7
	8	#include "AliHLTLogging.h"
	9	#include "AliHLTTrack.h"
	10	#include "AliHLTHoughTrack.h"
	11	#include "AliHLTTransform.h"
	12	#include "AliHLTHoughTransformerRow.h"
	13
	14	#if __GNUC__ >= 3
	15	using namespace std;
	16	#endif
	17
	18	/** \class AliHLTHoughTrack
	19	<pre>
	20	//_____________________________________________________________
	21	// AliHLTHoughTrack
	22	//
	23	// Track class for Hough tracklets
	24	//
	25	</pre>
	26	*/
	27
	28	ClassImp(AliHLTHoughTrack)
	29
	30
	31	AliHLTHoughTrack::AliHLTHoughTrack() : AliHLTTrack()
	32	{
	33	//Constructor
	34
	35	fWeight = 0;
	36	fMinDist=0;
	37	fDLine = 0;
	38	fPsiLine = 0;
	39	fIsHelix = true;
	40	fEtaIndex = -1;
	41	fEta = 0;
	42	ComesFromMainVertex(kTRUE);
	43	}
	44
	45	AliHLTHoughTrack::~AliHLTHoughTrack()
	46	{
	47	//dtor
	48	}
	49
	50	void AliHLTHoughTrack::Set(AliHLTTrack *track)
	51	{
	52	//Basically copy constructor
	53	AliHLTHoughTrack tpt = (AliHLTHoughTrack)track;
	54	SetTrackParameters(tpt->GetKappa(),tpt->GetPsi(),tpt->GetWeight());
	55	SetEtaIndex(tpt->GetEtaIndex());
	56	SetEta(tpt->GetEta());
	57	SetTgl(tpt->GetTgl());
	58	SetPsi(tpt->GetPsi());
	59	SetPterr(tpt->GetPterr());
	60	SetTglerr(tpt->GetTglerr());
	61	SetPsierr(tpt->GetPsierr());
	62	SetCenterX(tpt->GetCenterX());
	63	SetCenterY(tpt->GetCenterY());
	64	SetFirstPoint(tpt->GetFirstPointX(),tpt->GetFirstPointY(),tpt->GetFirstPointZ());
	65	SetLastPoint(tpt->GetLastPointX(),tpt->GetLastPointY(),tpt->GetLastPointZ());
	66	SetCharge(tpt->GetCharge());
	67	SetRowRange(tpt->GetFirstRow(),tpt->GetLastRow());
	68	SetSlice(tpt->GetSlice());
	69	SetHits(tpt->GetNHits(),(UInt_t *)tpt->GetHitNumbers());
	70	SetMCid(tpt->GetMCid());
	71	SetBinXY(tpt->GetBinX(),tpt->GetBinY(),tpt->GetSizeX(),tpt->GetSizeY());
	72	SetSector(tpt->GetSector());
	73	return;
	74
	75	// fWeight = tpt->GetWeight();
	76	// fDLine = tpt->GetDLine();
	77	// fPsiLine = tpt->GetPsiLine();
	78	// SetNHits(tpt->GetWeight());
	79	// SetRowRange(tpt->GetFirstRow(),tpt->GetLastRow());
	80	// fIsHelix = false;
	81	}
	82
	83	Int_t AliHLTHoughTrack::Compare(const AliHLTTrack *tpt) const
	84	{
	85	//Compare 2 hough tracks according to their weight
	86	AliHLTHoughTrack track = (AliHLTHoughTrack)tpt;
	87	if(track->GetWeight() < GetWeight()) return 1;
	88	if(track->GetWeight() > GetWeight()) return -1;
	89	return 0;
	90	}
	91
	92	void AliHLTHoughTrack::SetEta(Double_t f)
	93	{
	94	//Set eta, and calculate fTanl, which is the tan of dipangle
	95
	96	fEta = f;
	97	Double_t theta = 2atan(exp(-1.fEta));
	98	Double_t dipangle = AliHLTTransform::PiHalf() - theta;
	99	Double_t tgl = tan(dipangle);
	100	SetTgl(tgl);
	101	}
	102
	103	void AliHLTHoughTrack::UpdateToFirstRow()
	104	{
	105	//Update the track parameters to the point where track cross
	106	//its first padrow.`
	107
	108	//Get the crossing point with the first padrow:
	109	Float_t xyz[3];
	110	if(!GetCrossingPoint(GetFirstRow(),xyz))
	111	LOG(AliHLTLog::kWarning,"AliHLTHoughTrack::UpdateToFirstRow()","Track parameters")
	112	<<AliHLTLog::kDec<<"Track does not cross padrow "<<GetFirstRow()<<" centerx "
	113	<<GetCenterX()<<" centery "<<GetCenterY()<<" Radius "<<GetRadius()<<" tgl "<<GetTgl()<<ENDLOG;
	114
	115	//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());
	116	//printf("Before: first %f %f %f tgl %f center %f %f charge %d\n",GetFirstPointX(),GetFirstPointY(),GetFirstPointZ(),GetTgl(),GetCenterX(),GetCenterY(),GetCharge());
	117
	118	Double_t radius = sqrt(xyz[0]xyz[0] + xyz[1]xyz[1]);
	119
	120	//Get the track parameters
	121
	122	/*
	123	Double_t x0 = GetR0() * cos(GetPhi0()) ;
	124	Double_t y0 = GetR0() * sin(GetPhi0()) ;
	125	*/
	126	Double_t rc = GetRadius();//fabs(GetPt()) / AliHLTTransform::GetBFieldValue();
	127	Double_t tPhi0 = GetPsi() + GetCharge() * AliHLTTransform::PiHalf() / abs(GetCharge()) ;
	128	Double_t xc = GetCenterX();//x0 - rc * cos(tPhi0) ;
	129	Double_t yc = GetCenterY();//y0 - rc * sin(tPhi0) ;
	130
	131	//Check helix and cylinder intersect
	132	Double_t fac1 = xcxc + ycyc ;
	133	Double_t sfac = sqrt( fac1 ) ;
	134
	135	if ( fabs(sfac-rc) > radius \|\| fabs(sfac+rc) < radius ) {
	136	LOG(AliHLTLog::kError,"AliHLTHoughTrack::UpdateToFirstRow","Tracks")<<AliHLTLog::kDec<<
	137	"Track does not intersect"<<ENDLOG;
	138	return;
	139	}
	140
	141	//Find intersection
	142	Double_t fac2 = (radiusradius + fac1 - rcrc) / (2.00 * radius * sfac ) ;
	143	Double_t phi = atan2(yc,xc) + GetCharge()*acos(fac2) ;
	144	Double_t td = atan2(radiussin(phi) - yc,radiuscos(phi) - xc) ;
	145
	146	//Intersection in z
	147	if ( td < 0 ) td = td + AliHLTTransform::TwoPi();
	148	Double_t deltat = fmod((-GetCharge()td + GetCharge()tPhi0),AliHLTTransform::TwoPi());
	149	if ( deltat < 0. ) deltat += AliHLTTransform::TwoPi();
	150	else if ( deltat > AliHLTTransform::TwoPi() ) deltat -= AliHLTTransform::TwoPi();
	151	Double_t z = GetZ0() + rc * GetTgl() * deltat ;
	152
	153	Double_t xExtra = radius * cos(phi) ;
	154	Double_t yExtra = radius * sin(phi) ;
	155
	156	Double_t tPhi = atan2(yExtra-yc,xExtra-xc);
	157
	158	//if ( tPhi < 0 ) tPhi += 2. * M_PI ;
	159	Double_t tPsi = tPhi - GetCharge() * AliHLTTransform::PiHalf() / abs(GetCharge()) ;
	160	if ( tPsi > AliHLTTransform::TwoPi() ) tPsi -= AliHLTTransform::TwoPi() ;
	161	else if ( tPsi < 0. ) tPsi += AliHLTTransform::TwoPi();
	162
	163	//And finally, update the track parameters
	164	SetR0(radius);
	165	SetPhi0(phi);
	166	SetZ0(z);
	167	SetPsi(tPsi);
	168	SetFirstPoint(xyz[0],xyz[1],z);
	169	//printf("After: first %f %f %f tgl %f center %f %f charge %d\n",GetFirstPointX(),GetFirstPointY(),GetFirstPointZ(),GetTgl(),GetCenterX(),GetCenterY(),GetCharge());
	170
	171	//printf("First point set %f %f %f\n",xyz[0],xyz[1],z);
	172
	173	//Also, set the coordinates of the point where track crosses last padrow:
	174	GetCrossingPoint(GetLastRow(),xyz);
	175	SetLastPoint(xyz[0],xyz[1],xyz[2]);
	176	//printf("last point %f %f %f\n",xyz[0],xyz[1],xyz[2]);
	177	}
	178
	179	void AliHLTHoughTrack::SetTrackParameters(Double_t kappa,Double_t eangle,Int_t weight)
	180	{
	181	//Set track parameters - sort of ctor
	182	fWeight = weight;
	183	fMinDist = 100000;
	184	SetKappa(kappa);
	185	Double_t pt = fabs(AliHLTTransform::GetBFieldValue()/kappa);
	186	SetPt(pt);
	187	Double_t radius = 1/fabs(kappa);
	188	SetRadius(radius);
	189	SetFirstPoint(0,0,0);
	190	SetPsi(eangle); //Psi = emission angle when first point is vertex
	191	SetPhi0(0); //not defined for vertex reference point
	192	SetR0(0);
	193	Double_t charge = -1.*kappa;
	194	SetCharge((Int_t)copysign(1.,charge));
	195	Double_t trackPhi0 = GetPsi() + charge0.5AliHLTTransform::Pi()/fabs(charge);
	196	Double_t xc = GetFirstPointX() - GetRadius() * cos(trackPhi0) ;
	197	Double_t yc = GetFirstPointY() - GetRadius() * sin(trackPhi0) ;
	198	SetCenterX(xc);
	199	SetCenterY(yc);
	200	SetNHits(1); //just for the trackarray IO
	201	fIsHelix = true;
	202	}
	203
	204	void AliHLTHoughTrack::SetTrackParametersRow(Double_t alpha1,Double_t alpha2,Double_t eta,Int_t weight)
	205	{
	206	//Set track parameters for HoughTransformerRow
	207	//This includes curvature,emission angle and eta
	208	Double_t psi = atan((alpha1-alpha2)/(AliHLTHoughTransformerRow::GetBeta1()-AliHLTHoughTransformerRow::GetBeta2()));
	209	Double_t kappa = 2.0(alpha1cos(psi)-AliHLTHoughTransformerRow::GetBeta1()*sin(psi));
	210	SetTrackParameters(kappa,psi,weight);
	211
	212	Double_t zovr;
	213	Double_t etaparam1 = AliHLTHoughTransformerRow::GetEtaCalcParam1();
	214	Double_t etaparam2 = AliHLTHoughTransformerRow::GetEtaCalcParam2();
	215	if(eta>0)
	216	zovr = (etaparam1 - sqrt(etaparam1etaparam1 - 4.etaparam2eta))/(2.etaparam2);
	217	else
	218	zovr = -1.(etaparam1 - sqrt(etaparam1etaparam1 + 4.etaparam2eta))/(2.*etaparam2);
	219	Double_t r = sqrt(1.+zovr*zovr);
	220	Double_t exacteta = 0.5*log((1+zovr/r)/(1-zovr/r));
	221	SetEta(exacteta);
	222	}
	223
	224	void AliHLTHoughTrack::SetLineParameters(Double_t psi,Double_t D,Int_t weight,Int_t rowrange,Int_t /ref_row*/)
	225	{
	226	//Initialize a track piece, not yet a track
	227	//Used in case of straight line transformation
	228
	229	//Transform line parameters to coordinate system of slice:
	230
	231	// D = D + fTransform->Row2X(ref_row)*cos(psi);
	232
	233	fDLine = D;
	234	fPsiLine = psi;
	235	fWeight = weight;
	236	SetNHits(1);
	237	SetRowRange(rowrange[0],rowrange[1]);
	238	fIsHelix = false;
	239	}
	240
	241	void AliHLTHoughTrack::SetBestMCid(Int_t mcid,Double_t mindist)
	242	{
	243	//Finds and set the closest mc label
	244	if(mindist < fMinDist)
	245	{
	246	fMinDist = mindist;
	247	SetMCid(mcid);
	248	}
	249	}
	250
	251	void AliHLTHoughTrack::GetLineCrossingPoint(Int_t padrow,Float_t *xy)
	252	{
	253	//Returns the crossing point of the track with a given padrow
	254	if(fIsHelix)
	255	{
	256	printf("AliHLTHoughTrack::GetLineCrossingPoint : Track is not a line\n");
	257	return;
	258	}
	259
	260	Float_t xhit = AliHLTTransform::Row2X(padrow) - AliHLTTransform::Row2X(GetFirstRow());
	261	Float_t a = -1/tan(fPsiLine);
	262	Float_t b = fDLine/sin(fPsiLine);
	263	Float_t yhit = a*xhit + b;
	264	xy[0] = xhit;
	265	xy[1] = yhit;
	266	}