[u/mrichter/AliRoot.git] / HLT / src / AliL3ConfMapFit.cxx

// @(#) $Id$

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

#include "AliL3StandardIncludes.h"
#include "AliL3RootTypes.h"
#include "AliL3Logging.h"
#include "AliL3Vertex.h"
#include "AliL3ConfMapTrack.h"
#include "AliL3ConfMapPoint.h"
#include "AliL3Transform.h"
#include "AliL3ConfMapFit.h"

/** \class AliL3ConfMapFit
<pre>
//_____________________________________________________________
// AliL3ConfMapFit
//
// Fit class for conformal mapping tracking
</pre>
*/

ClassImp(AliL3ConfMapFit)


AliL3ConfMapFit::AliL3ConfMapFit(AliL3ConfMapTrack *track,AliL3Vertex *vertex)
{
  //constructor
  fTrack = track;
  fVertex = vertex;
}

Int_t AliL3ConfMapFit::FitHelix()
{
  //fit the helix
  if(FitCircle())
    {
      LOG(AliL3Log::kError,"AliL3ConfMapFit::FitHelix","TrackFit")<<AliL3Log::kDec<<
	"Problems during circle fit"<<ENDLOG;
      return 1;
    }
  if(FitLine())
    {
      LOG(AliL3Log::kError,"AliL3ConfMapFit::FitHelix","TrackFit")<<AliL3Log::kDec<<
	"Problems during line fit"<<ENDLOG;
      return 1;
    }
  return 0;
}

Int_t AliL3ConfMapFit::FitCircle()
{
  //-----------------------------------------------------------------
  //Fits circle parameters using algorithm
  //described by ChErnov and Oskov in Computer Physics
  //Communications.
  // 
  //Written in FORTRAN by Jawluen Tang, Physics department , UT-Austin 
  //Moved to C by Pablo Yepes
  //Moved to AliROOT by ASV.
  //------------------------------------------------------------------
  
  Double_t wsum  = 0.0 ;
  Double_t xav   = 0.0 ;
  Double_t yav   = 0.0 ;
  
  Int_t num_of_hits = fTrack->GetNumberOfPoints();
  //
  //     Loop over hits calculating average
  Int_t co=0;
  
  for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit())
    {
      co++;
      AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint*)fTrack->GetCurrentHit();
      cHit->SetXYWeight( 1./ (Double_t)(cHit->GetXerr()*cHit->GetXerr() + cHit->GetYerr()*cHit->GetYerr()) );
      wsum      += cHit->GetXYWeight() ;
      xav       += cHit->GetXYWeight() * cHit->GetX() ;
      yav       += cHit->GetXYWeight() * cHit->GetY() ;
    }
  if(co!=num_of_hits) 
    LOG(AliL3Log::kError,"AliL3ConfMapFit::FitCircle","TrackFit")<<AliL3Log::kDec<<
      "Mismatch of hits. Counter: "<<co<<" nHits: "<<num_of_hits<<ENDLOG;
  if (fTrack->ComesFromMainVertex() == true)
    {    
      wsum += fVertex->GetXYWeight() ;
      xav  += fVertex->GetX() ;
      yav  += fVertex->GetY() ;
    }
  
  xav = xav / wsum ;
  yav = yav / wsum ;
//
//  CALCULATE <X**2>, <XY>, AND <Y**2> WITH <X> = 0, & <Y> = 0
//
  Double_t xxav  = 0.0 ;
  Double_t xyav  = 0.0 ; 
  Double_t yyav  = 0.0 ;
  Double_t xi, yi ;

  for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit())
    { 
      //AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint *)hits->At(hit_counter);
      AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint*)fTrack->GetCurrentHit();
      xi        = cHit->GetX() - xav ;
      yi        = cHit->GetY() - yav ;
      xxav     += xi * xi * cHit->GetXYWeight() ;
      xyav     += xi * yi * cHit->GetXYWeight() ;
      yyav     += yi * yi * cHit->GetXYWeight() ;
    }
  
  if (fTrack->ComesFromMainVertex() == true)
    {
      xi        = fVertex->GetX() - xav ;
      yi        = fVertex->GetY() - yav ;
      xxav     += xi * xi * fVertex->GetXYWeight() ;
      xyav     += xi * yi * fVertex->GetXYWeight() ;
      yyav     += yi * yi * fVertex->GetXYWeight() ; 
    }
  xxav = xxav / wsum ;
  xyav = xyav / wsum ;
  yyav = yyav / wsum ;
//
//-->  ROTATE COORDINATES SO THAT <XY> = 0
//
//-->  SIGN(C**2 - S**2) = SIGN(XXAV - YYAV) >
//-->  &                                     > ==> NEW : (XXAV-YYAV) > 0
//-->  SIGN(S) = SIGN(XYAV)                  >

  Double_t a = fabs( xxav - yyav ) ;
  Double_t b = 4.0 * xyav * xyav ;

  Double_t asqpb  = a * a + b  ;
  Double_t rasqpb = sqrt ( asqpb) ;

  Double_t splus  = 1.0 + a / rasqpb ;
  Double_t sminus = b / (asqpb * splus) ;

  splus  = sqrt (0.5 * splus ) ;
  sminus = sqrt (0.5 * sminus) ;
//
//->  FIRST REQUIRE : SIGN(C**2 - S**2) = SIGN(XXAV - YYAV)
//
  Double_t sinrot, cosrot ;
  if ( xxav <= yyav ) {
	 cosrot = sminus ;
	 sinrot = splus  ;
  }
  else {
	  cosrot = splus ;
	  sinrot = sminus ;
  }
//
//->  REQUIRE : SIGN(S) = SIGN(XYAV) * SIGN(C) (ASSUMING SIGN(C) > 0)
//
  if ( xyav < 0.0 ) sinrot = - sinrot ;
//
//-->  WE NOW HAVE THE SMALLEST ANGLE THAT GUARANTEES <X**2> > <Y**2>
//-->  TO GET THE SIGN OF THE CHARGE RIGHT, THE NEW X-AXIS MUST POINT
//-->  OUTWARD FROM THE ORGIN.  WE ARE FREE TO CHANGE SIGNS OF BOTH
//-->  COSROT AND SINROT SIMULTANEOUSLY TO ACCOMPLISH THIS.
//
//-->  CHOOSE SIGN OF C WISELY TO BE ABLE TO GET THE SIGN OF THE CHARGE
//
  if ( cosrot*xav+sinrot*yav < 0.0 ) {
	  cosrot = -cosrot ;
	  sinrot = -sinrot ;
  }
//
//->  NOW GET <R**2> AND RSCALE= SQRT(<R**2>)
//
  Double_t rrav   = xxav + yyav ;
  Double_t rscale = sqrt(rrav) ;

  xxav   = 0.0 ;
  yyav   = 0.0 ;
  xyav   = 0.0 ;
  Double_t xrrav = 0.0 ;
  Double_t yrrav = 0.0 ;
  Double_t rrrrav  = 0.0 ;

  Double_t xixi, yiyi, riri, wiriri, xold, yold ;
  
  //for (hit_counter=0; hit_counter<num_of_hits; hit_counter++) 
  for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit())  
    { 
      //AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint*)hits->At(hit_counter);  
      AliL3ConfMapPoint* cHit = (AliL3ConfMapPoint*)fTrack->GetCurrentHit();

      xold = cHit->GetX() - xav ;
      yold = cHit->GetY() - yav ;
      //
      //-->  ROTATE SO THAT <XY> = 0 & DIVIDE BY RSCALE SO THAT <R**2> = 1
      //
      xi = (  cosrot * xold + sinrot * yold ) / rscale ;
      yi = ( -sinrot * xold + cosrot * yold ) / rscale ;
      
      xixi   = xi * xi ;
      yiyi   = yi * yi ;
      riri   = xixi + yiyi ;
      wiriri = cHit->GetXYWeight() * riri ;
      
      xyav   += cHit->GetXYWeight() * xi * yi ;
      xxav   += cHit->GetXYWeight() * xixi ;
      yyav   += cHit->GetXYWeight() * yiyi ;
      
      xrrav  += wiriri * xi ;
      yrrav  += wiriri * yi ;
      rrrrav += wiriri * riri ;
    }
  //
//   Include vertex if required
//
  if (fTrack->ComesFromMainVertex() == true)
    {
	xold = fVertex->GetX() - xav ;
	yold = fVertex->GetY() - yav ;
	//
	//-->  ROTATE SO THAT <XY> = 0 & DIVIDE BY RSCALE SO THAT <R**2> = 1
	//
	xi = (  cosrot * xold + sinrot * yold ) / rscale ;
	yi = ( -sinrot * xold + cosrot * yold ) / rscale ;
	
	xixi   = xi * xi ;
	yiyi   = yi * yi ;
	riri   = xixi + yiyi ;
	wiriri = fVertex->GetXYWeight() * riri ;

	xyav   += fVertex->GetXYWeight() * xi * yi ;
	xxav   += fVertex->GetXYWeight() * xixi ;
	yyav   += fVertex->GetXYWeight() * yiyi ;

	xrrav  += wiriri * xi ;
	yrrav  += wiriri * yi ;
	rrrrav += wiriri * riri ;
  }
  //
  //    
  //
  //-->  DIVIDE BY WSUM TO MAKE AVERAGES
  //
  xxav    = xxav   / wsum ;
  yyav    = yyav   / wsum ;
  xrrav   = xrrav  / wsum ;
  yrrav   = yrrav  / wsum ;
  rrrrav  = rrrrav / wsum ;
  xyav    = xyav   / wsum ;

  Int_t const ntry = 5 ;
//
//-->  USE THESE TO GET THE COEFFICIENTS OF THE 4-TH ORDER POLYNIMIAL
//-->  DON'T PANIC - THE THIRD ORDER TERM IS ZERO !
//
  Double_t xrrxrr = xrrav * xrrav ;
  Double_t yrryrr = yrrav * yrrav ;
  Double_t rrrrm1 = rrrrav - 1.0  ;
  Double_t xxyy   = xxav  * yyav  ;        

  Double_t c0  =          rrrrm1*xxyy - xrrxrr*yyav - yrryrr*xxav ;
  Double_t c1  =        - rrrrm1      + xrrxrr      + yrryrr   - 4.0*xxyy ;        
  Double_t c2  =   4.0  + rrrrm1                               - 4.0*xxyy ;           
  Double_t c4  = - 4.0  ;                
//
//-->  COEFFICIENTS OF THE DERIVATIVE - USED IN NEWTON-RAPHSON ITERATIONS
//
  Double_t c2d =   2.0 * c2 ;
  Double_t c4d =   4.0 * c4 ;
//
//-->  0'TH VALUE OF LAMDA - LINEAR INTERPOLATION BETWEEN P(0) & P(YYAV)
//
//   LAMDA = YYAV * C0 / (C0 + YRRSQ * (XXAV-YYAV))
  Double_t lamda  = 0.0 ;
  Double_t dlamda = 0.0 ;
//
  Double_t chiscl = wsum * rscale * rscale ;
  Double_t dlamax = 0.001 / chiscl ;   
   
  Double_t p, pd ;
  for ( int itry = 1 ; itry <= ntry ; itry++ ) {
     p      = c0 + lamda * (c1 + lamda * (c2 + lamda * lamda * c4 )) ;
     pd     = (c1 + lamda * (c2d + lamda * lamda * c4d)) ;
     dlamda = -p / pd ;
     lamda  = lamda + dlamda ;
     if (fabs(dlamda)<   dlamax) break ;
  }

  Double_t chi2 = (Double_t)(chiscl * lamda) ;
 
  fTrack->SetChiSq1(chi2);
  // Double_t dchisq = chiscl * dlamda ;	     
//
//-->  NOW CALCULATE THE MATRIX ELEMENTS FOR ALPHA, BETA & KAPPA
//
  Double_t h11   = xxav  -     lamda ;
  Double_t h14   = xrrav ;
  Double_t h22   = yyav  -     lamda ; 
  Double_t h24   = yrrav ;
  Double_t h34   = 1.0   + 2.0*lamda ;
  if ( h11 == 0.0 || h22 == 0.0 ){
    LOG(AliL3Log::kError,"AliL3ConfMapFit::FitCircle","TrackFit")<<AliL3Log::kDec<<
      "Problems fitting circle"<<ENDLOG;
    return 1 ;
  }
  Double_t rootsq = (h14*h14)/(h11*h11) + 4.0*h34 ;

  Double_t ratio, kappa, beta ;
  if ( fabs(h22) > fabs(h24) ) {
     ratio  = h24 / h22 ;
     rootsq = ratio * ratio + rootsq ;
     kappa = 1.0 / sqrt(rootsq) ;
     beta  = - ratio * kappa ;
  }
  else {
     ratio  = h22 / h24 ;
     rootsq = 1.0 + ratio * ratio * rootsq ;
     beta  = 1.0 / sqrt(rootsq) ;
     if ( h24 > 0 ) beta = - beta ;
     kappa = -ratio * beta ;
  }            
  Double_t alpha = - (h14/h11) * kappa ;
//
//-->  transform these into the lab coordinate system
//-->  first get kappa and back to real dimensions
//
  Double_t kappa1 = kappa / rscale ;
  Double_t dbro   = 0.5   / kappa1 ;
//
//-->  next rotate alpha and beta and scale
//
  Double_t alphar = (cosrot * alpha - sinrot * beta)* dbro ;
  Double_t betar  = (sinrot * alpha + cosrot * beta)* dbro ;
//
//-->  then translate by (xav,yav)
//
  Double_t acent  = (double)(xav - alphar) ;
  Double_t bcent  = (double)(yav - betar ) ;
  Double_t radius = (double)dbro ;
//
//   Get charge
//
  Int_t q = ( ( yrrav < 0 ) ? 1 : -1 ) ;

  fTrack->SetCharge(q);
  
  
  //Set the first point on the track to the space point coordinates of the innermost track
  //This will be updated to lie on the fit later on (AliL3Track::UpdateToFirstPoint).
  Double_t x0,y0,psi,pt ;
  AliL3ConfMapPoint *lHit = (AliL3ConfMapPoint*)fTrack->GetLastHit();
  x0 = lHit->GetX();
  y0 = lHit->GetY();
  fTrack->SetFirstPoint(x0,y0,0); //Z-value is set in FitLine

  psi  = (Double_t)atan2(bcent-y0,acent-x0) ;
  psi  = psi + q * AliL3Transform::PiHalf();
  if ( psi < 0 ) psi = psi + AliL3Transform::TwoPi();
  pt   = (Double_t)(AliL3Transform::GetBFieldValue() * radius ) ;
  
  //Update the track parameters with the parameters from this fit:
  fTrack->SetPsi(psi);
  fTrack->SetPt(pt);
  fTrack->SetRadius(radius);
  fTrack->SetCenterX(acent);
  fTrack->SetCenterY(bcent);

  //
//    Get errors from fast fit
//
  //if ( getPara()->getErrors ) getErrorsCircleFit ( acent, bcent, radius ) ;
//
  return 0 ;
  
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//    Fit Line in s-z plane
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Int_t AliL3ConfMapFit::FitLine ( )
{
  //
  //Initialization 
  //
  Double_t sum = 0.F ;
  Double_t ss  = 0.F ;
  Double_t sz  = 0.F ;
  Double_t sss = 0.F ;
  Double_t ssz = 0.F ;
  //
  //find sum , sums ,sumz, sumss 
  // 
  Double_t dx, dy ;
  Double_t radius = (Double_t)(fTrack->GetPt() / AliL3Transform::GetBFieldValue() ) ;

  //TObjArray *hits = fTrack->GetHits();
  //Int_t num_of_hits = fTrack->GetNumberOfPoints();

  if (0)// fTrack->ComesFromMainVertex() == true ) 
    {
      dx = ((AliL3ConfMapPoint*)fTrack->GetFirstHit())->GetX() - fVertex->GetX();
      dy = ((AliL3ConfMapPoint*)fTrack->GetFirstHit())->GetY() - fVertex->GetY() ;
    }
  else 
    {
      dx = ((AliL3ConfMapPoint *)fTrack->GetFirstHit())->GetX() - ((AliL3ConfMapPoint *)fTrack->GetLastHit())->GetX() ;
      dy = ((AliL3ConfMapPoint *)fTrack->GetFirstHit())->GetY() - ((AliL3ConfMapPoint *)fTrack->GetLastHit())->GetY() ;
      //dx = ((AliL3ConfMapPoint *)hits->First())->GetX() - ((AliL3ConfMapPoint *)hits->Last())->GetX() ;
      //dy = ((AliL3ConfMapPoint *)hits->First())->GetY() - ((AliL3ConfMapPoint *)hits->Last())->GetY() ;
    }
  
  Double_t localPsi = 0.5F * sqrt ( dx*dx + dy*dy ) / radius ;
  Double_t total_s ;
  
  if ( fabs(localPsi) < 1. ) 
    {
      total_s = 2.0 * radius * asin ( localPsi ) ;
    } 
  else 
    { 
      total_s = 2.0 * radius * AliL3Transform::Pi() ;
    } 
  
  AliL3ConfMapPoint *previousHit = NULL;

  // FtfBaseHit *previousHit = 0  ;
  
  //for ( startLoop() ; done() ; nextHit() ) {
  Double_t dpsi,s;

  //  for(hit_counter=0; hit_counter<num_of_hits; hit_counter++)
  for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit())  
    {
      // AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint*)hits->At(hit_counter);
      AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint*)fTrack->GetCurrentHit();
      // if ( GetCurrentHit() != GetFirstHit() ) 
      if(cHit != fTrack->GetFirstHit())//  hits->First())
	{
	  dx   = cHit->GetX() - previousHit->GetX() ;
	  dy   = cHit->GetY() - previousHit->GetY() ;
	  dpsi = 0.5 * (Double_t)sqrt ( dx*dx + dy*dy ) / radius ;
	  fTrack->SetPsierr(dpsi);
	  s = previousHit->GetS() - 2.0 * radius * (Double_t)asin ( dpsi ) ;
	  cHit->SetS(s);
	}
      else
	cHit->SetS(total_s);
      //	cHit->s = total_s ;
    
      sum += cHit->GetZWeight() ;
      ss  += cHit->GetZWeight() * cHit->GetS() ;
      sz  += cHit->GetZWeight() * cHit->GetZ() ;
      sss += cHit->GetZWeight() * cHit->GetS() * cHit->GetS() ;
      ssz += cHit->GetZWeight() * cHit->GetS() * cHit->GetZ() ;
      previousHit = cHit ;
    }
  
  Double_t chi2,det = sum * sss - ss * ss;
  if ( fabs(det) < 1e-20)
    { 
      chi2 = 99999.F ;
      fTrack->SetChiSq2(chi2);
      return 0 ;
    }
  
  //Compute the best fitted parameters A,B
  Double_t tanl,z0,dtanl,dz0;

  tanl = (Double_t)((sum * ssz - ss * sz ) / det );
  z0   = (Double_t)((sz * sss - ssz * ss ) / det );

  fTrack->SetTgl(tanl);
  fTrack->SetZ0(z0);
  
  //     calculate chi-square 
  
  chi2 = 0.;
  Double_t r1 ;
  
  //for(hit_counter=0; hit_counter<num_of_hits; hit_counter++)
  for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit())  
    {
      //AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint*)hits->At(hit_counter);
      AliL3ConfMapPoint *cHit = (AliL3ConfMapPoint*)fTrack->GetCurrentHit();
      r1   = cHit->GetZ() - tanl * cHit->GetS() - z0 ;
      chi2 += (Double_t) ( (Double_t)cHit->GetZWeight() * (r1 * r1) );
    }
  fTrack->SetChiSq2(chi2);
  //
  //     calculate estimated variance
  //      varsq=chi/(double(n)-2.) 
  //     calculate covariance matrix 
  //      siga=sqrt(varsq*sxx/det) 
  //      sigb=sqrt(varsq*sum/det) 
  //
  dtanl = (Double_t) ( sum / det );
  dz0   = (Double_t) ( sss / det );
  
  fTrack->SetTglerr(dtanl);
  fTrack->SetZ0err(dz0);
  
  return 0 ;
}
Commit	Line	Data
3e87ef69	1	// @(#) $Id$
9392f4fd	2
b661165c	3	// Author: Anders Vestbo <mailto:vestbo@fi.uib.no>
3e87ef69	4	//*-- Copyright &copy ALICE HLT Group
b661165c	5
118c26c3	6	#include "AliL3StandardIncludes.h"
e9ecfae3	7	#include "AliL3RootTypes.h"
108615fc	8	#include "AliL3Logging.h"
108615fc	9	#include "AliL3Vertex.h"
	10	#include "AliL3ConfMapTrack.h"
	11	#include "AliL3ConfMapPoint.h"
ef79795d	12	#include "AliL3Transform.h"
e9ecfae3	13	#include "AliL3ConfMapFit.h"
108615fc	14
3e87ef69	15	/** \class AliL3ConfMapFit
3e87ef69	16	<pre>
b661165c	17	//_____________________________________________________________
108615fc	18	// AliL3ConfMapFit
	19	//
	20	// Fit class for conformal mapping tracking
3e87ef69	21	</pre>
3e87ef69	22	*/
108615fc	23
	24	ClassImp(AliL3ConfMapFit)
	25
108615fc	26
	27	AliL3ConfMapFit::AliL3ConfMapFit(AliL3ConfMapTrack track,AliL3Vertex vertex)
	28	{
	29	//constructor
	30	fTrack = track;
	31	fVertex = vertex;
108615fc	32	}
	33
	34	Int_t AliL3ConfMapFit::FitHelix()
	35	{
b1ed0288	36	//fit the helix
108615fc	37	if(FitCircle())
	38	{
	39	LOG(AliL3Log::kError,"AliL3ConfMapFit::FitHelix","TrackFit")<<AliL3Log::kDec<<
	40	"Problems during circle fit"<<ENDLOG;
	41	return 1;
	42	}
	43	if(FitLine())
	44	{
	45	LOG(AliL3Log::kError,"AliL3ConfMapFit::FitHelix","TrackFit")<<AliL3Log::kDec<<
	46	"Problems during line fit"<<ENDLOG;
	47	return 1;
	48	}
	49	return 0;
	50	}
	51
	52	Int_t AliL3ConfMapFit::FitCircle()
	53	{
	54	//-----------------------------------------------------------------
	55	//Fits circle parameters using algorithm
	56	//described by ChErnov and Oskov in Computer Physics
	57	//Communications.
	58	//
	59	//Written in FORTRAN by Jawluen Tang, Physics department , UT-Austin
	60	//Moved to C by Pablo Yepes
	61	//Moved to AliROOT by ASV.
	62	//------------------------------------------------------------------
	63
	64	Double_t wsum = 0.0 ;
	65	Double_t xav = 0.0 ;
	66	Double_t yav = 0.0 ;
	67
	68	Int_t num_of_hits = fTrack->GetNumberOfPoints();
	69	//
	70	// Loop over hits calculating average
	71	Int_t co=0;
	72
	73	for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit())
	74	{
	75	co++;
b1ed0288	76	AliL3ConfMapPoint cHit = (AliL3ConfMapPoint)fTrack->GetCurrentHit();
108615fc	77	cHit->SetXYWeight( 1./ (Double_t)(cHit->GetXerr()cHit->GetXerr() + cHit->GetYerr()cHit->GetYerr()) );
	78	wsum += cHit->GetXYWeight() ;
	79	xav += cHit->GetXYWeight() * cHit->GetX() ;
	80	yav += cHit->GetXYWeight() * cHit->GetY() ;
	81	}
	82	if(co!=num_of_hits)
	83	LOG(AliL3Log::kError,"AliL3ConfMapFit::FitCircle","TrackFit")<<AliL3Log::kDec<<
	84	"Mismatch of hits. Counter: "<<co<<" nHits: "<<num_of_hits<<ENDLOG;
	85	if (fTrack->ComesFromMainVertex() == true)
	86	{
	87	wsum += fVertex->GetXYWeight() ;
	88	xav += fVertex->GetX() ;
	89	yav += fVertex->GetY() ;
	90	}
	91
	92	xav = xav / wsum ;
	93	yav = yav / wsum ;
	94	//
	95	// CALCULATE <X2>, <XY>, AND <Y2> WITH <X> = 0, & <Y> = 0
	96	//
	97	Double_t xxav = 0.0 ;
	98	Double_t xyav = 0.0 ;
	99	Double_t yyav = 0.0 ;
	100	Double_t xi, yi ;
	101
	102	for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit())
	103	{
	104	//AliL3ConfMapPoint cHit = (AliL3ConfMapPoint )hits->At(hit_counter);
b1ed0288	105	AliL3ConfMapPoint cHit = (AliL3ConfMapPoint)fTrack->GetCurrentHit();
108615fc	106	xi = cHit->GetX() - xav ;
	107	yi = cHit->GetY() - yav ;
	108	xxav += xi * xi * cHit->GetXYWeight() ;
	109	xyav += xi * yi * cHit->GetXYWeight() ;
	110	yyav += yi * yi * cHit->GetXYWeight() ;
	111	}
	112
	113	if (fTrack->ComesFromMainVertex() == true)
	114	{
	115	xi = fVertex->GetX() - xav ;
	116	yi = fVertex->GetY() - yav ;
	117	xxav += xi * xi * fVertex->GetXYWeight() ;
	118	xyav += xi * yi * fVertex->GetXYWeight() ;
	119	yyav += yi * yi * fVertex->GetXYWeight() ;
	120	}
	121	xxav = xxav / wsum ;
	122	xyav = xyav / wsum ;
	123	yyav = yyav / wsum ;
	124	//
	125	//--> ROTATE COORDINATES SO THAT <XY> = 0
	126	//
	127	//--> SIGN(C2 - S2) = SIGN(XXAV - YYAV) >
	128	//--> & > ==> NEW : (XXAV-YYAV) > 0
	129	//--> SIGN(S) = SIGN(XYAV) >
	130
	131	Double_t a = fabs( xxav - yyav ) ;
	132	Double_t b = 4.0 * xyav * xyav ;
	133
	134	Double_t asqpb = a * a + b ;
	135	Double_t rasqpb = sqrt ( asqpb) ;
	136
	137	Double_t splus = 1.0 + a / rasqpb ;
	138	Double_t sminus = b / (asqpb * splus) ;
	139
	140	splus = sqrt (0.5 * splus ) ;
	141	sminus = sqrt (0.5 * sminus) ;
	142	//
	143	//-> FIRST REQUIRE : SIGN(C2 - S2) = SIGN(XXAV - YYAV)
	144	//
	145	Double_t sinrot, cosrot ;
	146	if ( xxav <= yyav ) {
	147	cosrot = sminus ;
	148	sinrot = splus ;
	149	}
	150	else {
	151	cosrot = splus ;
	152	sinrot = sminus ;
	153	}
	154	//
	155	//-> REQUIRE : SIGN(S) = SIGN(XYAV) * SIGN(C) (ASSUMING SIGN(C) > 0)
	156	//
	157	if ( xyav < 0.0 ) sinrot = - sinrot ;
	158	//
	159	//--> WE NOW HAVE THE SMALLEST ANGLE THAT GUARANTEES <X2> > <Y2>
	160	//--> TO GET THE SIGN OF THE CHARGE RIGHT, THE NEW X-AXIS MUST POINT
	161	//--> OUTWARD FROM THE ORGIN. WE ARE FREE TO CHANGE SIGNS OF BOTH
	162	//--> COSROT AND SINROT SIMULTANEOUSLY TO ACCOMPLISH THIS.
	163	//
	164	//--> CHOOSE SIGN OF C WISELY TO BE ABLE TO GET THE SIGN OF THE CHARGE
	165	//
	166	if ( cosrotxav+sinrotyav < 0.0 ) {
	167	cosrot = -cosrot ;
	168	sinrot = -sinrot ;
	169	}
170	//
171	//-> NOW GET <R2> AND RSCALE= SQRT(<R2>)
172	//
173	Double_t rrav = xxav + yyav ;
174	Double_t rscale = sqrt(rrav) ;
175
176	xxav = 0.0 ;
177	yyav = 0.0 ;
178	xyav = 0.0 ;
179	Double_t xrrav = 0.0 ;
180	Double_t yrrav = 0.0 ;
181	Double_t rrrrav = 0.0 ;
182
183	Double_t xixi, yiyi, riri, wiriri, xold, yold ;
184
185	//for (hit_counter=0; hit_counter<num_of_hits; hit_counter++)
186	for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit())
187	{
188	//AliL3ConfMapPoint cHit = (AliL3ConfMapPoint)hits->At(hit_counter);
b1ed0288	189	AliL3ConfMapPoint* cHit = (AliL3ConfMapPoint*)fTrack->GetCurrentHit();
108615fc	190
	191	xold = cHit->GetX() - xav ;
	192	yold = cHit->GetY() - yav ;
	193	//
	194	//--> ROTATE SO THAT <XY> = 0 & DIVIDE BY RSCALE SO THAT <R**2> = 1
	195	//
	196	xi = ( cosrot * xold + sinrot * yold ) / rscale ;
	197	yi = ( -sinrot * xold + cosrot * yold ) / rscale ;
	198
	199	xixi = xi * xi ;
	200	yiyi = yi * yi ;
	201	riri = xixi + yiyi ;
	202	wiriri = cHit->GetXYWeight() * riri ;
	203
	204	xyav += cHit->GetXYWeight() * xi * yi ;
	205	xxav += cHit->GetXYWeight() * xixi ;
	206	yyav += cHit->GetXYWeight() * yiyi ;
	207
	208	xrrav += wiriri * xi ;
	209	yrrav += wiriri * yi ;
	210	rrrrav += wiriri * riri ;
	211	}
	212	//
	213	// Include vertex if required
	214	//
	215	if (fTrack->ComesFromMainVertex() == true)
	216	{
	217	xold = fVertex->GetX() - xav ;
	218	yold = fVertex->GetY() - yav ;
	219	//
	220	//--> ROTATE SO THAT <XY> = 0 & DIVIDE BY RSCALE SO THAT <R**2> = 1
	221	//
	222	xi = ( cosrot * xold + sinrot * yold ) / rscale ;
	223	yi = ( -sinrot * xold + cosrot * yold ) / rscale ;
	224
	225	xixi = xi * xi ;
	226	yiyi = yi * yi ;
	227	riri = xixi + yiyi ;
	228	wiriri = fVertex->GetXYWeight() * riri ;
	229
	230	xyav += fVertex->GetXYWeight() * xi * yi ;
	231	xxav += fVertex->GetXYWeight() * xixi ;
	232	yyav += fVertex->GetXYWeight() * yiyi ;
	233
	234	xrrav += wiriri * xi ;
	235	yrrav += wiriri * yi ;
	236	rrrrav += wiriri * riri ;
	237	}
	238	//
	239	//
	240	//
	241	//--> DIVIDE BY WSUM TO MAKE AVERAGES
	242	//
	243	xxav = xxav / wsum ;
	244	yyav = yyav / wsum ;
	245	xrrav = xrrav / wsum ;
	246	yrrav = yrrav / wsum ;
	247	rrrrav = rrrrav / wsum ;
	248	xyav = xyav / wsum ;
	249
	250	Int_t const ntry = 5 ;
	251	//
	252	//--> USE THESE TO GET THE COEFFICIENTS OF THE 4-TH ORDER POLYNIMIAL
	253	//--> DON'T PANIC - THE THIRD ORDER TERM IS ZERO !
254	//
255	Double_t xrrxrr = xrrav * xrrav ;
256	Double_t yrryrr = yrrav * yrrav ;
257	Double_t rrrrm1 = rrrrav - 1.0 ;
258	Double_t xxyy = xxav * yyav ;
259
260	Double_t c0 = rrrrm1xxyy - xrrxrryyav - yrryrr*xxav ;
261	Double_t c1 = - rrrrm1 + xrrxrr + yrryrr - 4.0*xxyy ;
262	Double_t c2 = 4.0 + rrrrm1 - 4.0*xxyy ;
263	Double_t c4 = - 4.0 ;
264	//
265	//--> COEFFICIENTS OF THE DERIVATIVE - USED IN NEWTON-RAPHSON ITERATIONS
266	//
267	Double_t c2d = 2.0 * c2 ;
268	Double_t c4d = 4.0 * c4 ;
269	//
270	//--> 0'TH VALUE OF LAMDA - LINEAR INTERPOLATION BETWEEN P(0) & P(YYAV)
271	//
272	// LAMDA = YYAV * C0 / (C0 + YRRSQ * (XXAV-YYAV))
273	Double_t lamda = 0.0 ;
274	Double_t dlamda = 0.0 ;
275	//
276	Double_t chiscl = wsum * rscale * rscale ;
277	Double_t dlamax = 0.001 / chiscl ;
278
279	Double_t p, pd ;
280	for ( int itry = 1 ; itry <= ntry ; itry++ ) {
281	p = c0 + lamda * (c1 + lamda * (c2 + lamda * lamda * c4 )) ;
282	pd = (c1 + lamda * (c2d + lamda * lamda * c4d)) ;
283	dlamda = -p / pd ;
284	lamda = lamda + dlamda ;
285	if (fabs(dlamda)< dlamax) break ;
286	}
287
288	Double_t chi2 = (Double_t)(chiscl * lamda) ;
289
290	fTrack->SetChiSq1(chi2);
291	// Double_t dchisq = chiscl * dlamda ;
292	//
293	//--> NOW CALCULATE THE MATRIX ELEMENTS FOR ALPHA, BETA & KAPPA
294	//
295	Double_t h11 = xxav - lamda ;
296	Double_t h14 = xrrav ;
297	Double_t h22 = yyav - lamda ;
298	Double_t h24 = yrrav ;
299	Double_t h34 = 1.0 + 2.0*lamda ;
300	if ( h11 == 0.0 \|\| h22 == 0.0 ){
301	LOG(AliL3Log::kError,"AliL3ConfMapFit::FitCircle","TrackFit")<<AliL3Log::kDec<<
302	"Problems fitting circle"<<ENDLOG;
303	return 1 ;
304	}
305	Double_t rootsq = (h14h14)/(h11h11) + 4.0*h34 ;
306
307	Double_t ratio, kappa, beta ;
308	if ( fabs(h22) > fabs(h24) ) {
309	ratio = h24 / h22 ;
310	rootsq = ratio * ratio + rootsq ;
311	kappa = 1.0 / sqrt(rootsq) ;
312	beta = - ratio * kappa ;
313	}
314	else {
315	ratio = h22 / h24 ;
316	rootsq = 1.0 + ratio * ratio * rootsq ;
317	beta = 1.0 / sqrt(rootsq) ;
318	if ( h24 > 0 ) beta = - beta ;
319	kappa = -ratio * beta ;
320	}
321	Double_t alpha = - (h14/h11) * kappa ;
322	//
323	//--> transform these into the lab coordinate system
324	//--> first get kappa and back to real dimensions
325	//
326	Double_t kappa1 = kappa / rscale ;
327	Double_t dbro = 0.5 / kappa1 ;
328	//
329	//--> next rotate alpha and beta and scale
330	//
331	Double_t alphar = (cosrot * alpha - sinrot * beta)* dbro ;
332	Double_t betar = (sinrot * alpha + cosrot * beta)* dbro ;
333	//
334	//--> then translate by (xav,yav)
335	//
336	Double_t acent = (double)(xav - alphar) ;
337	Double_t bcent = (double)(yav - betar ) ;
338	Double_t radius = (double)dbro ;
339	//
340	// Get charge
341	//
5dd30052	342	Int_t q = ( ( yrrav < 0 ) ? 1 : -1 ) ;
108615fc	343
	344	fTrack->SetCharge(q);
	345
1f1942b8	346
	347	//Set the first point on the track to the space point coordinates of the innermost track
	348	//This will be updated to lie on the fit later on (AliL3Track::UpdateToFirstPoint).
0bd0c1ef	349	Double_t x0,y0,psi,pt ;
b1ed0288	350	AliL3ConfMapPoint lHit = (AliL3ConfMapPoint)fTrack->GetLastHit();
0bd0c1ef	351	x0 = lHit->GetX();
0bd0c1ef	352	y0 = lHit->GetY();
1f1942b8	353	fTrack->SetFirstPoint(x0,y0,0); //Z-value is set in FitLine
1f1942b8	354
108615fc	355	psi = (Double_t)atan2(bcent-y0,acent-x0) ;
5a31e9df	356	psi = psi + q * AliL3Transform::PiHalf();
	357	if ( psi < 0 ) psi = psi + AliL3Transform::TwoPi();
	358	pt = (Double_t)(AliL3Transform::GetBFieldValue() * radius ) ;
1f1942b8	359
1f1942b8	360	//Update the track parameters with the parameters from this fit:
108615fc	361	fTrack->SetPsi(psi);
108615fc	362	fTrack->SetPt(pt);
1f1942b8	363	fTrack->SetRadius(radius);
	364	fTrack->SetCenterX(acent);
	365	fTrack->SetCenterY(bcent);
108615fc	366
	367	//
	368	// Get errors from fast fit
	369	//
	370	//if ( getPara()->getErrors ) getErrorsCircleFit ( acent, bcent, radius ) ;
	371	//
	372	return 0 ;
	373
	374	}
	375
	376	//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	377	// Fit Line in s-z plane
	378	//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	379	Int_t AliL3ConfMapFit::FitLine ( )
	380	{
	381	//
	382	//Initialization
	383	//
	384	Double_t sum = 0.F ;
	385	Double_t ss = 0.F ;
	386	Double_t sz = 0.F ;
	387	Double_t sss = 0.F ;
	388	Double_t ssz = 0.F ;
	389	//
	390	//find sum , sums ,sumz, sumss
	391	//
	392	Double_t dx, dy ;
5a31e9df	393	Double_t radius = (Double_t)(fTrack->GetPt() / AliL3Transform::GetBFieldValue() ) ;
108615fc	394
	395	//TObjArray *hits = fTrack->GetHits();
	396	//Int_t num_of_hits = fTrack->GetNumberOfPoints();
	397
0bd0c1ef	398	if (0)// fTrack->ComesFromMainVertex() == true )
108615fc	399	{
b1ed0288	400	dx = ((AliL3ConfMapPoint*)fTrack->GetFirstHit())->GetX() - fVertex->GetX();
b1ed0288	401	dy = ((AliL3ConfMapPoint*)fTrack->GetFirstHit())->GetY() - fVertex->GetY() ;
108615fc	402	}
	403	else
	404	{
b1ed0288	405	dx = ((AliL3ConfMapPoint )fTrack->GetFirstHit())->GetX() - ((AliL3ConfMapPoint )fTrack->GetLastHit())->GetX() ;
b1ed0288	406	dy = ((AliL3ConfMapPoint )fTrack->GetFirstHit())->GetY() - ((AliL3ConfMapPoint )fTrack->GetLastHit())->GetY() ;
108615fc	407	//dx = ((AliL3ConfMapPoint )hits->First())->GetX() - ((AliL3ConfMapPoint )hits->Last())->GetX() ;
	408	//dy = ((AliL3ConfMapPoint )hits->First())->GetY() - ((AliL3ConfMapPoint )hits->Last())->GetY() ;
	409	}
	410
	411	Double_t localPsi = 0.5F * sqrt ( dxdx + dydy ) / radius ;
	412	Double_t total_s ;
	413
	414	if ( fabs(localPsi) < 1. )
	415	{
	416	total_s = 2.0 * radius * asin ( localPsi ) ;
	417	}
	418	else
	419	{
5a31e9df	420	total_s = 2.0 * radius * AliL3Transform::Pi() ;
108615fc	421	}
	422
	423	AliL3ConfMapPoint *previousHit = NULL;
	424
	425	// FtfBaseHit *previousHit = 0 ;
	426
	427	//for ( startLoop() ; done() ; nextHit() ) {
	428	Double_t dpsi,s;
	429
	430	// for(hit_counter=0; hit_counter<num_of_hits; hit_counter++)
	431	for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit())
	432	{
	433	// AliL3ConfMapPoint cHit = (AliL3ConfMapPoint)hits->At(hit_counter);
b1ed0288	434	AliL3ConfMapPoint cHit = (AliL3ConfMapPoint)fTrack->GetCurrentHit();
	435	// if ( GetCurrentHit() != GetFirstHit() )
	436	if(cHit != fTrack->GetFirstHit())// hits->First())
108615fc	437	{
	438	dx = cHit->GetX() - previousHit->GetX() ;
	439	dy = cHit->GetY() - previousHit->GetY() ;
	440	dpsi = 0.5 * (Double_t)sqrt ( dxdx + dydy ) / radius ;
	441	fTrack->SetPsierr(dpsi);
	442	s = previousHit->GetS() - 2.0 * radius * (Double_t)asin ( dpsi ) ;
	443	cHit->SetS(s);
	444	}
	445	else
	446	cHit->SetS(total_s);
	447	// cHit->s = total_s ;
	448
	449	sum += cHit->GetZWeight() ;
	450	ss += cHit->GetZWeight() * cHit->GetS() ;
	451	sz += cHit->GetZWeight() * cHit->GetZ() ;
	452	sss += cHit->GetZWeight() * cHit->GetS() * cHit->GetS() ;
	453	ssz += cHit->GetZWeight() * cHit->GetS() * cHit->GetZ() ;
	454	previousHit = cHit ;
	455	}
	456
	457	Double_t chi2,det = sum * sss - ss * ss;
	458	if ( fabs(det) < 1e-20)
	459	{
	460	chi2 = 99999.F ;
	461	fTrack->SetChiSq2(chi2);
	462	return 0 ;
	463	}
	464
	465	//Compute the best fitted parameters A,B
	466	Double_t tanl,z0,dtanl,dz0;
	467
	468	tanl = (Double_t)((sum * ssz - ss * sz ) / det );
	469	z0 = (Double_t)((sz * sss - ssz * ss ) / det );
	470
	471	fTrack->SetTgl(tanl);
	472	fTrack->SetZ0(z0);
	473
	474	// calculate chi-square
	475
	476	chi2 = 0.;
	477	Double_t r1 ;
	478
	479	//for(hit_counter=0; hit_counter<num_of_hits; hit_counter++)
	480	for(fTrack->StartLoop(); fTrack->LoopDone(); fTrack->GetNextHit())
	481	{
	482	//AliL3ConfMapPoint cHit = (AliL3ConfMapPoint)hits->At(hit_counter);
b1ed0288	483	AliL3ConfMapPoint cHit = (AliL3ConfMapPoint)fTrack->GetCurrentHit();
108615fc	484	r1 = cHit->GetZ() - tanl * cHit->GetS() - z0 ;
	485	chi2 += (Double_t) ( (Double_t)cHit->GetZWeight() * (r1 * r1) );
	486	}
	487	fTrack->SetChiSq2(chi2);
	488	//
	489	// calculate estimated variance
	490	// varsq=chi/(double(n)-2.)
	491	// calculate covariance matrix
	492	// siga=sqrt(varsq*sxx/det)
	493	// sigb=sqrt(varsq*sum/det)
	494	//
	495	dtanl = (Double_t) ( sum / det );
	496	dz0 = (Double_t) ( sss / det );
	497
	498	fTrack->SetTglerr(dtanl);
	499	fTrack->SetZ0err(dz0);
	500
	501	return 0 ;
	502	}