BKLMTrackFitter Class Reference

track fitting procedure More...

#include <BKLMTrackFitter.h>

Public Member Functions
	BKLMTrackFitter ()
	Default constructor.
	~BKLMTrackFitter ()
	Destructor.
double	fit (std::list< KLMHit2d * > &listTrackPoint)
	do fit and returns chi square of the fit.
double	distanceToHit (KLMHit2d *hit, double &error, double &sigma)
	Distance from track to a hit in the plane of the module.
double	globalDistanceToHit (KLMHit2d *hit, double &error, double &sigma)
	Distance from track to a hit in the global system.
double	fit1dSectorTrack (std::list< KLMHit2d * > hitList, CLHEP::HepVector &eta, CLHEP::HepSymMatrix &error, int depDir, int indDir)
	do fit in the y-x plane or z-x plane
double	fit1dTrack (std::list< KLMHit2d * > hitList, CLHEP::HepVector &eta, CLHEP::HepSymMatrix &error, int depDir, int indDir)
	do fit in the global system
CLHEP::HepVector	getTrackParam ()
	Get track parameters in the global system. y = p0 + p1 * x; y = p2 + p3 * z, if in local sector fit mode: y = p0 + p1 * x; z = p2 + p3 * x.
CLHEP::HepSymMatrix	getTrackParamErr ()
	Get invariance matrix of track parameters in the global system.
CLHEP::HepVector	getTrackParamSector ()
	Get track parameters in the sector locan system, y = p0 + p1 * x, z = p2 + p3 *x, where the first layer of the sector is used as reference.
CLHEP::HepSymMatrix	getTrackParamSectorErr ()
	Get invariance matrix of track parameters in the sector local system, where the first layer of the sector is used as reference.
bool	isValid ()
	Is fit valid.
bool	isGood ()
	Is fit good.
float	getChi2 ()
	Chi square of the fit.
int	getNumHit ()
	number of the hits on this track
void	inValidate ()
	Invalidate track.
void	setGlobalFit (bool localOrGlobal)
	set the fitting mode, local system or global system

Private Attributes
bool	m_Valid
	Is fit valid.
bool	m_Good
	Is fit good.
float	m_Chi2
	Chi square of fit.
int	m_NumHit
	the number of hits on this track
bool	m_globalFit
	do fit in the local system or global system false: local sys; true: global sys.
CLHEP::HepVector	m_SectorPar
	track params in the sector local system
CLHEP::HepSymMatrix	m_SectorErr
	track params errors in the sector local system
CLHEP::HepVector	m_GlobalPar
	track params in global system
CLHEP::HepSymMatrix	m_GlobalErr
	track params errors in global system
bklm::GeometryPar *	m_GeoPar
	pointer to GeometryPar singleton

Detailed Description

track fitting procedure

Definition at line 29 of file BKLMTrackFitter.h.

Constructor & Destructor Documentation

BKLMTrackFitter()

BKLMTrackFitter

(

)

Default constructor.

Constructor.

Definition at line 40 of file BKLMTrackFitter.cc.

                                :
  m_Valid(false),
  m_Good(false),
  m_Chi2(0.0),
  m_NumHit(0),
  m_globalFit(false),
  m_SectorPar(4, 0),
  m_SectorErr(4, 0),
  m_GlobalPar(4, 0),
  m_GlobalErr(4, 0),
  m_GeoPar(nullptr)
{
}

~BKLMTrackFitter()

~BKLMTrackFitter

(

)

Destructor.

Definition at line 55 of file BKLMTrackFitter.cc.

{
}

Member Function Documentation

distanceToHit()

double distanceToHit	(	KLMHit2d *	hit,
		double &	error,
		double &	sigma
	)

Distance from track to a hit in the plane of the module.

Definition at line 155 of file BKLMTrackFitter.cc.

{
 
  double x, y, z, dy, dz;
 
  if (!m_Valid) {
    error = DBL_MAX;
    sigma = DBL_MAX;
    return DBL_MAX;
  }
 
  m_GeoPar = GeometryPar::instance();
  const Belle2::bklm::Module* refMod = m_GeoPar->findModule(hit->getSection(), hit->getSector(), 1);
  const Belle2::bklm::Module* corMod = m_GeoPar->findModule(hit->getSection(), hit->getSector(), hit->getLayer());
 
  CLHEP::Hep3Vector globalPos(hit->getPositionX(), hit->getPositionY(), hit->getPositionZ());
 
  //+++ local coordinates of the hit
  CLHEP::Hep3Vector local = refMod->globalToLocal(globalPos);
 
  x = local[0] ;
 
  y = m_SectorPar[ AY ] + x * m_SectorPar[ BY ];
  z = m_SectorPar[ AZ ] + x * m_SectorPar[ BZ ];
 
  dy = y - local[1];
  dz = z - local[2];
 
  double distance = sqrt(dy * dy + dz * dz);
 
  // Error is composed of four parts: error due to tracking, y and z;
  // and error in hit, y and z. We know the latter two, got to find
  // the first two. We could calculate this from simple equations or
  // using matrices. I choose the later because it is extendable.
  HepMatrix  errors(2, 2, 0);    // Matrix for errors
  HepMatrix  A(2, 4, 0);         // Matrix for derivatives
 
  // Derivatives of y (z) = a + bx with respect to a and b.
  A[ MY ][ AY ] = 1.0;
  A[ MY ][ BY ] =   x;
  A[ MZ ][ AZ ] = 1.0;
  A[ MZ ][ BZ ] =   x;
 
  errors = A * m_SectorErr * A.T();
 
  double hit_localPhiErr = corMod->getPhiStripWidth() / sqrt(12);
  double hit_localZErr = corMod->getZStripWidth() / sqrt(12);
 
  if (hit->inRPC()) {
    //+++ scale localErr based on measured-in-Belle resolution
    int nStrips = hit->getPhiStripMax() - hit->getPhiStripMin() + 1;
    double dn = nStrips - 1.5;
    double factor = std::pow((0.9 + 0.4 * dn * dn), 1.5) * 0.60;//measured-in-Belle resolution
    hit_localPhiErr = hit_localPhiErr * sqrt(factor);
 
    nStrips = hit->getZStripMax() - hit->getZStripMin() + 1;
    dn = nStrips - 1.5;
    factor = std::pow((0.9 + 0.4 * dn * dn), 1.5) * 0.55;//measured-in-Belle resolution
    hit_localZErr = hit_localZErr * sqrt(factor);
  }
 
  error = sqrt(errors[ MY ][ MY ] +
               errors[ MZ ][ MZ ] +
               pow(hit_localPhiErr, 2) +
               pow(hit_localZErr, 2));
 
  if (error != 0.0) {
    sigma = distance / error;
  } else {
    sigma = DBL_MAX;
  }
 
  return (distance);
}

fit()

double fit

(

std::list< KLMHit2d * > &

listTrackPoint

)

do fit and returns chi square of the fit.

Definition at line 60 of file BKLMTrackFitter.cc.

{
 
  // We can only do fit if there are at least two hits
  if (listHitSector.size() < 2) {
    m_Valid = false;
    m_Good  = false;
    return (false);
  }
 
  HepVector     eta(2, 0);             //  ( a, b ) in y = a + bx
  HepSymMatrix  error(2, 0);
  HepVector     gloEta(2, 0);          //  ( a, b ) in y = a + bx in global system
  HepSymMatrix  gloError(2, 0);
  m_Chi2 = 0;
 
  // Create temporary vector and matrix... so size can be set.
  HepVector     sectorPar(4, 0);
  HepSymMatrix  sectorErr(4, 0);
  HepVector     globalPar(4, 0);
  HepSymMatrix  globalErr(4, 0);
 
  if (m_globalFit) {
    m_Chi2  = fit1dTrack(listHitSector, eta, error, VY, VX);
    globalPar.sub(1, eta);
    globalErr.sub(1, error);
  } else {
    m_Chi2  = fit1dSectorTrack(listHitSector, eta, error, VY, VX);
    sectorPar.sub(1, eta);
    sectorErr.sub(1, error);
  }
 
  if (m_globalFit) {
    m_Chi2  += fit1dTrack(listHitSector, eta, error, VY, VZ);
    globalPar.sub(3, eta);
    globalErr.sub(3, error);
  } else {
    m_Chi2 += fit1dSectorTrack(listHitSector, eta, error, VZ, VX);
    sectorPar.sub(3, eta);
    sectorErr.sub(3, error);
  }
 
  if (!m_globalFit) {
    //transfer to the global system, choose two arbitrary points on track within in the sector jpionts on this track
    const Belle2::bklm::Module* refMod = m_GeoPar->findModule((*listHitSector.begin())->getSection(),
                                                              (*listHitSector.begin())->getSector(), 1);
 
    Hep3Vector p1(0, 0, 0); Hep3Vector p2(0, 0, 0);
    double x1 = 5; // sector localX
    double x2 = 10;
    double y1 = sectorPar[0] + sectorPar[1] * x1;
    double y2 = sectorPar[0] + sectorPar[1] * x2;
    double z1 = sectorPar[2] + sectorPar[3] * x1;
    double z2 = sectorPar[2] + sectorPar[3] * x2;
    p1.setX(x1); p1.setY(y1); p1.setZ(z1);
    p2.setX(x2); p2.setY(y2); p2.setZ(z2);
    Hep3Vector gl1 = refMod->localToGlobal(p1);
    Hep3Vector gl2 = refMod->localToGlobal(p2);
 
    //transfer the trackParameters to global system y = p0 + p1 * x  and z= p2 + p3*x
    if (gl2[0] != gl1[0]) {
      globalPar[1] = (gl2[1] - gl1[1]) / (gl2[0] - gl1[0]);
      globalPar[0] = gl1[1] - globalPar[1] * gl1[0];
      globalPar[3] = (gl2[2] - gl1[2]) / (gl2[0] - gl1[0]);
      globalPar[2] = gl1[2] - globalPar[3] * gl1[0];
      globalErr = sectorErr;
    } else {
      globalPar[1] = DBL_MAX;
      globalPar[0] = DBL_MAX;
      globalPar[3] = DBL_MAX;
      globalPar[2] = DBL_MAX;
      globalErr = sectorErr; //?
    }
  } else { //transfer to the local system, can not do. One global track might go through two different sectors.
  }
 
  m_Chi2 /= 2.0;
 
  m_SectorPar = sectorPar;
  m_SectorErr = sectorErr;
  m_GlobalPar = globalPar;
  m_GlobalErr = globalErr;
 
  m_Valid = true;
  m_Good  = false;
  m_NumHit =  listHitSector.size();
  if (m_Chi2 <= 20.0) {
    m_Good = true;
  }
 
  return (m_Chi2);
 
}

fit1dSectorTrack()

double fit1dSectorTrack	(	std::list< KLMHit2d * >	hitList,
		CLHEP::HepVector &	eta,
		CLHEP::HepSymMatrix &	error,
		int	depDir,
		int	indDir
	)

do fit in the y-x plane or z-x plane

Definition at line 331 of file BKLMTrackFitter.cc.

{
 
// Fit d = a + bi, where d is dependent direction and i is independent
  Hep3Vector localHitPos;
  HepMatrix  localHitErr(3, 3, 0);
 
  double     indPos = 0;
  double     depPos = 0;
 
  // Matrix based solution
 
  int noPoints = hitList.size();
 
  // Derivative of y = a + bx, with respect to a and b evaluated at x.
  HepMatrix  A(noPoints, 2, 0);
 
  // Measured data points.
  HepVector  y(noPoints, 0);
 
  // Inverse of covariance (error) matrix, also known as the weight matrix.
  // In plain English: V_y_inverse_nn = 1 / (error of nth measurement)^2
  HepDiagMatrix V_y_inverse(noPoints, 0);
  //HepSymMatrix V_y_inverse(noPoints, 0);
 
  // Error or correlation matrix for coefficients (2x2 matrices)
  HepSymMatrix  V_A, V_A_inverse;
 
  int section = (*hitList.begin())->getSection();
  int sector  = (*hitList.begin())->getSector();
 
  m_GeoPar = GeometryPar::instance();
  const Belle2::bklm::Module* refMod = m_GeoPar->findModule(section, sector, 1);
 
  int n = 0;
  for (KLMHit2d* hit : hitList) {
 
    if (hit->getSection() != section || hit->getSector() != sector) {
      continue;
    }
 
    // m_GeoPar = GeometryPar::instance();
    //const Belle2::bklm::Module* refMod = m_GeoPar->findModule(hit->getSection(), hit->getSector(), 1);
    const Belle2::bklm::Module* corMod = m_GeoPar->findModule(hit->getSection(), hit->getSector(), hit->getLayer());
 
    CLHEP::Hep3Vector globalPos;
    globalPos[0] = hit->getPositionX();
    globalPos[1] = hit->getPositionY();
    globalPos[2] = hit->getPositionZ();
 
    localHitPos = refMod->globalToLocal(globalPos);
    double hit_localPhiErr = corMod->getPhiStripWidth() / sqrt(12);
    double hit_localZErr = corMod->getZStripWidth() / sqrt(12);
 
    if (hit->inRPC()) {
      //+++ scale localErr based on measured-in-Belle resolution
      int nStrips = hit->getPhiStripMax() - hit->getPhiStripMin() + 1;
      double dn = nStrips - 1.5;
      double factor = std::pow((0.9 + 0.4 * dn * dn), 1.5) * 0.60;//measured-in-Belle resolution
      hit_localPhiErr = hit_localPhiErr * sqrt(factor);
 
      nStrips = hit->getZStripMax() - hit->getZStripMin() + 1;
      dn = nStrips - 1.5;
      factor = std::pow((0.9 + 0.4 * dn * dn), 1.5) * 0.55;//measured-in-Belle resolution
      hit_localZErr = hit_localZErr * sqrt(factor);
    }
 
    localHitErr[0][0] = 0.0; //x
    localHitErr[0][1] = 0;
    localHitErr[0][2] = 0;
    localHitErr[1][1] = hit_localPhiErr;
    localHitErr[1][0] = 0;
    localHitErr[1][2] = 0;
    localHitErr[2][2] = hit_localZErr;
    localHitErr[2][0] = 0;
    localHitErr[2][1] = 0;
 
    switch (indDir) {
 
      case VX:
        indPos = localHitPos.x();
        break;
 
      case VY:
        indPos = localHitPos.y();
        break;
 
      case VZ:
        indPos = localHitPos.z();
        break;
 
      default:
        B2DEBUG(20, "error in klm_trackSectorFit: illegal direction");
 
    }
 
    switch (depDir) {
 
      case VX:
        depPos = localHitPos.x();
        break;
 
      case VY:
        depPos = localHitPos.y();
        break;
 
      case VZ:
        depPos = localHitPos.z();
        break;
 
      default:
        B2DEBUG(20, "error in klm_trackSectorFit: illegal direction");
 
    }
 
 
    A[ n ][ 0 ] = 1;
    A[ n ][ 1 ] = indPos;
 
    y[ n ] = depPos;
 
    if (localHitErr[ depDir ][ depDir ] > 0.0) {
      V_y_inverse[ n ][ n ] = 1.0 / localHitErr[ depDir ][ depDir ];
    } else {
      V_y_inverse[ n ][ n ] = DBL_MAX;
    }
    ++n;//n is the index of measured points/hits
  }
 
  V_A_inverse = V_y_inverse.similarityT(A);
 
  int ierr = 0;
  V_A = V_A_inverse.inverse(ierr);
 
  eta   = V_A * A.T() * V_y_inverse * y;
  error = V_A;
 
// Calculate residuals:
  HepMatrix residual = y - A * eta;
  HepMatrix chisqr = residual.T() * V_y_inverse * residual;
 
  return (chisqr.trace());
 
}

fit1dTrack()

double fit1dTrack	(	std::list< KLMHit2d * >	hitList,
		CLHEP::HepVector &	eta,
		CLHEP::HepSymMatrix &	error,
		int	depDir,
		int	indDir
	)

do fit in the global system

do fit in global system, handle tracks that go through multi-sectors

Definition at line 480 of file BKLMTrackFitter.cc.

{
// Fit d = a + bi, where d is dependent direction and i is independent
// in global system we assume y = a + b*x and y = c + d*z  different from local fit
 
  HepMatrix globalHitErr(3, 3, 0);
 
  double     indPos = 0;
  double     depPos = 0;
 
  // Matrix based solution
  int noPoints = hitList.size();
 
  // Derivative of y = a + bx, with respect to a and b evaluated at x.
  HepMatrix  A(noPoints, 2, 0);
 
  // Measured data points.
  HepVector  y(noPoints, 0);
 
  // Inverse of covariance (error) matrix, also known as the weight matrix.
  // In plain English: V_y_inverse_nn = 1 / (error of nth measurement)^2
  HepDiagMatrix V_y_inverse(noPoints, 0);
 
  // Error or correlation matrix for coefficients (2x2 matrices)
  HepSymMatrix  V_A, V_A_inverse;
 
  m_GeoPar = GeometryPar::instance();
  const Belle2::bklm::Module* corMod;
 
  int n = 0;
  for (KLMHit2d* hit : hitList) {
 
    // m_GeoPar = GeometryPar::instance();
    //const Belle2::bklm::Module* refMod = m_GeoPar->findModule(hit->getSection(), hit->getSector(), 1);
    corMod = m_GeoPar->findModule(hit->getSection(), hit->getSector(), hit->getLayer());
 
    CLHEP::Hep3Vector globalPos;
    globalPos[0] = hit->getPositionX();
    globalPos[1] = hit->getPositionY();
    globalPos[2] = hit->getPositionZ();
 
    //localHitPos = refMod->globalToLocal(globalPos);
    double hit_localPhiErr = corMod->getPhiStripWidth() / sqrt(12);
    double hit_localZErr = corMod->getZStripWidth() / sqrt(12);
 
    if (hit->inRPC()) {
      //+++ scale localErr based on measured-in-Belle resolution
      int nStrips = hit->getPhiStripMax() - hit->getPhiStripMin() + 1;
      double dn = nStrips - 1.5;
      double factor = std::pow((0.9 + 0.4 * dn * dn), 1.5) * 0.60;//measured-in-Belle resolution
      hit_localPhiErr = hit_localPhiErr * sqrt(factor);
 
      nStrips = hit->getZStripMax() - hit->getZStripMin() + 1;
      dn = nStrips - 1.5;
      factor = std::pow((0.9 + 0.4 * dn * dn), 1.5) * 0.55;//measured-in-Belle resolution
      hit_localZErr = hit_localZErr * sqrt(factor);
    }
 
    Hep3Vector globalOrigin = corMod->getGlobalOrigin();
    double sinphi = globalOrigin[1] / globalOrigin.mag();
    double cosphi = globalOrigin[0] / globalOrigin.mag();
 
    globalHitErr[0][0] = pow(hit_localPhiErr * sinphi, 2); //x
    globalHitErr[0][1] = (hit_localPhiErr * sinphi) * (hit_localPhiErr * cosphi);
    globalHitErr[0][2] = 0;
    globalHitErr[1][1] = pow(hit_localPhiErr * cosphi, 2);;
    globalHitErr[1][0] = (hit_localPhiErr * sinphi) * (hit_localPhiErr * cosphi);
    globalHitErr[1][2] = 0;
    globalHitErr[2][2] = pow(hit_localZErr, 2);;
    globalHitErr[2][0] = 0;
    globalHitErr[2][1] = 0;
 
    switch (indDir) {
 
      case VX:
        indPos = globalPos.x();
        break;
 
      case VY:
        indPos = globalPos.y();
        break;
 
      case VZ:
        indPos = globalPos.z();
        break;
 
      default:
        B2DEBUG(20, "error in bklm trackFit: illegal direction");
 
    }
 
    switch (depDir) {
 
      case VX:
        depPos = globalPos.x();
        break;
 
      case VY:
        depPos = globalPos.y();
        break;
 
      case VZ:
        depPos = globalPos.z();
        break;
 
      default:
        B2DEBUG(20, "error in bklm trackFit: illegal direction");
 
    }
 
 
    A[ n ][ 0 ] = 1;
    A[ n ][ 1 ] = indPos;
 
    y[ n ] = depPos;
 
    double error_raw = globalHitErr[indDir][indDir] + globalHitErr[depDir][depDir];
    //double correlate_ = 2.0*globalHitErr[indDir][depDir]; //?
    //double weight= error_raw - correlate_;
    double weight = error_raw;
    if (weight > 0) {
      V_y_inverse[ n ][ n ] = 1.0 / weight;
    } else {
      V_y_inverse[ n ][ n ] = DBL_MAX;
    }
    ++n;//n is the index of measured points/hits
  }
 
  //HepMatrix AT = A.T();
  //HepMatrix tmp = AT*V_y_inverse;
  //V_A_inverse = tmp*A;
  V_A_inverse = V_y_inverse.similarityT(A);
 
  int ierr = 0;
  V_A = V_A_inverse.inverse(ierr);
 
  eta   = V_A * A.T() * V_y_inverse * y;
  error = V_A;
 
// Calculate residuals:
  HepMatrix residual = y - A * eta;
  HepMatrix chisqr = residual.T() * V_y_inverse * residual;
 
  return (chisqr.trace());
 
}

getChi2()

float getChi2 ( )

inline

Chi square of the fit.

Definition at line 101 of file BKLMTrackFitter.h.

    {
      return m_Chi2;
    }

getNumHit()

int getNumHit ( )

inline

number of the hits on this track

Definition at line 107 of file BKLMTrackFitter.h.

    {
      return m_NumHit;
    }

getTrackParam()

CLHEP::HepVector getTrackParam ( )

inline

Get track parameters in the global system. y = p0 + p1 * x; y = p2 + p3 * z, if in local sector fit mode: y = p0 + p1 * x; z = p2 + p3 * x.

Definition at line 65 of file BKLMTrackFitter.h.

    {
      return m_GlobalPar;
    }

getTrackParamErr()

CLHEP::HepSymMatrix getTrackParamErr ( )

inline

Get invariance matrix of track parameters in the global system.

Definition at line 71 of file BKLMTrackFitter.h.

    {
      return m_GlobalErr;
    }

getTrackParamSector()

CLHEP::HepVector getTrackParamSector ( )

inline

Get track parameters in the sector locan system, y = p0 + p1 * x, z = p2 + p3 *x, where the first layer of the sector is used as reference.

Definition at line 77 of file BKLMTrackFitter.h.

    {
      return m_SectorPar;
    }

getTrackParamSectorErr()

CLHEP::HepSymMatrix getTrackParamSectorErr ( )

inline

Get invariance matrix of track parameters in the sector local system, where the first layer of the sector is used as reference.

Definition at line 83 of file BKLMTrackFitter.h.

    {
      return m_SectorErr;
    }

globalDistanceToHit()

double globalDistanceToHit	(	KLMHit2d *	hit,
		double &	error,
		double &	sigma
	)

Distance from track to a hit in the global system.

Distance from track to a hit calculated in the global system.

Definition at line 233 of file BKLMTrackFitter.cc.

{
 
  if (!m_Valid) {
    error = DBL_MAX;
    sigma = DBL_MAX;
    return DBL_MAX;
  }
 
  //in global fit, we have two functions y = a + b*x and y = c + d*z
  double x_mea = hit->getPositionX();
  double y_mea = hit->getPositionY();
  double z_mea = hit->getPositionZ();
 
  double x_pre = (y_mea - m_GlobalPar[ AY ]) / m_GlobalPar[ BY ]; //y_mea has uncertainties actually
  double z_pre = (y_mea - m_GlobalPar[ AZ ]) / m_GlobalPar[ BZ ];
 
  double dx = x_pre - x_mea;
  double dz = z_pre - z_mea;
 
  double distance = sqrt(dx * dx + dz * dz);
 
  // Error is composed of four parts: error due to tracking;
  // and error in hit, y, x  or y, z.
  HepMatrix  errors(2, 2, 0);    // Matrix for errors
  HepMatrix  A(2, 4, 0);         // Matrix for derivatives
 
  // Derivatives of x (z) = y/b - a/b with respect to a and b.
  A[ MY ][ AY ] = -1. / m_GlobalPar[BY];
  A[ MY ][ BY ] = -1 * (y_mea - m_GlobalPar[ AY ]) / (m_GlobalPar[ BY ] * m_GlobalPar[ BY ]);
  A[ MZ ][ AZ ] = -1. / m_GlobalPar[ BZ ];
  A[ MZ ][ BZ ] = -1 * (y_mea - m_GlobalPar[ AZ ]) / (m_GlobalPar[ BZ ] * m_GlobalPar[ BZ ]);
 
  //error from trackPar is inclueded, error from y_mea is not included
  errors = A * m_GlobalErr * A.T();
 
  //here get the resolustion of a hit, repeated several times, ugly. should we store this in KLMHit2d object ?
  const Belle2::bklm::Module* corMod = m_GeoPar->findModule(hit->getSection(), hit->getSector(), hit->getLayer());
  double hit_localPhiErr = corMod->getPhiStripWidth() / sqrt(12);
  double hit_localZErr = corMod->getZStripWidth() / sqrt(12);
 
  if (hit->inRPC()) {
    //+++ scale localErr based on measured-in-Belle resolution
    int nStrips = hit->getPhiStripMax() - hit->getPhiStripMin() + 1;
    double dn = nStrips - 1.5;
    double factor = std::pow((0.9 + 0.4 * dn * dn), 1.5) * 0.60;//measured-in-Belle resolution
    hit_localPhiErr = hit_localPhiErr * sqrt(factor);
 
    nStrips = hit->getZStripMax() - hit->getZStripMin() + 1;
    dn = nStrips - 1.5;
    factor = std::pow((0.9 + 0.4 * dn * dn), 1.5) * 0.55;//measured-in-Belle resolution
    hit_localZErr = hit_localZErr * sqrt(factor);
  }
 
  Hep3Vector globalOrigin = corMod->getGlobalOrigin();
  double sinphi = globalOrigin[1] / globalOrigin.mag();
  double cosphi = globalOrigin[0] / globalOrigin.mag();
 
  HepMatrix globalHitErr(3, 3, 0);
  globalHitErr[0][0] = pow(hit_localPhiErr * sinphi, 2); //x
  globalHitErr[0][1] = (hit_localPhiErr * sinphi) * (hit_localPhiErr * cosphi);
  globalHitErr[0][2] = 0;
  globalHitErr[1][1] = pow(hit_localPhiErr * cosphi, 2);;
  globalHitErr[1][0] = (hit_localPhiErr * sinphi) * (hit_localPhiErr * cosphi);
  globalHitErr[1][2] = 0;
  globalHitErr[2][2] = pow(hit_localZErr, 2);
  globalHitErr[2][0] = 0;
  globalHitErr[2][1] = 0;
 
  //HepMatrix  B(2, 2, 0);         // Matrix for derivatives
 
  // Derivatives of x (z) = y/b - a/b with respect to y.
  //B[ MY ][ AY ] = 1./m_GlobalPar[BY];
  //B[ MZ ][ BY ] = 1./m_GlobalPar[BZ] ;
  //double errors_b[0] = B[ MY ][ AY ]*globalHitErr[1][1];
  //double errors_b[1] = B[ MZ ][ BY ]*globalHitErr[1][1];
 
  HepMatrix error_mea(2, 2, 0);
  error = sqrt(errors[ MY ][ MY ] +
               errors[ MZ ][ MZ ] +
               //errors_b[0] + errors_b[1] + //error of prediced point due to error of inPos (y_mea)
               globalHitErr[0][0] +
               globalHitErr[1][1] + //y_mea error is correlated to the error of predicted point, but we didn't consider that part in errors
               globalHitErr[2][2]); //we ignore y_mea error?
 
  if (error != 0.0) {
    sigma = distance / error;
  } else {
    sigma = DBL_MAX;
  }
 
  return (distance);
}

inValidate()

void inValidate ( )

inline

Invalidate track.

Definition at line 113 of file BKLMTrackFitter.h.

    {
      m_Valid = false;
    }

isGood()

bool isGood ( )

inline

Is fit good.

Definition at line 95 of file BKLMTrackFitter.h.

    {
      return m_Good;
    }

isValid()

bool isValid ( )

inline

Is fit valid.

Definition at line 89 of file BKLMTrackFitter.h.

    {
      return m_Valid;
    }

setGlobalFit()

void setGlobalFit ( bool  localOrGlobal )

inline

set the fitting mode, local system or global system

Definition at line 119 of file BKLMTrackFitter.h.

    {
      m_globalFit = localOrGlobal;
    }

Member Data Documentation

m_Chi2

float m_Chi2

private

Chi square of fit.

Definition at line 133 of file BKLMTrackFitter.h.

m_GeoPar

bklm::GeometryPar* m_GeoPar

private

pointer to GeometryPar singleton

Definition at line 154 of file BKLMTrackFitter.h.

m_GlobalErr

CLHEP::HepSymMatrix m_GlobalErr

private

track params errors in global system

Definition at line 151 of file BKLMTrackFitter.h.

m_globalFit

bool m_globalFit

private

do fit in the local system or global system false: local sys; true: global sys.

Definition at line 139 of file BKLMTrackFitter.h.

m_GlobalPar

CLHEP::HepVector m_GlobalPar

private

track params in global system

Definition at line 148 of file BKLMTrackFitter.h.

m_Good

bool m_Good

private

Is fit good.

Definition at line 130 of file BKLMTrackFitter.h.

m_NumHit

int m_NumHit

private

the number of hits on this track

Definition at line 136 of file BKLMTrackFitter.h.

m_SectorErr

CLHEP::HepSymMatrix m_SectorErr

private

track params errors in the sector local system

Definition at line 145 of file BKLMTrackFitter.h.

m_SectorPar

CLHEP::HepVector m_SectorPar

private

track params in the sector local system

Definition at line 142 of file BKLMTrackFitter.h.

m_Valid

bool m_Valid

private

Is fit valid.

Definition at line 127 of file BKLMTrackFitter.h.

---

The documentation for this class was generated from the following files:

• klm/bklm/modules/bklmTracking/include/BKLMTrackFitter.h
• klm/bklm/modules/bklmTracking/src/BKLMTrackFitter.cc