FastVertexFit Class Reference

#include <FastVertexFit.h>

List of all members.

Public Member Functions
	~FastVertexFit ()
void	init ()
void	addTrack (const int number, const HepVector helix, const HepSymMatrix err)
bool	Fit ()
double	chisq () const
VertexParameter	vtx () const
HepVector	Vx () const
HepSymMatrix	Evx () const
HepVector	Pull () const
Static Public Member Functions
static FastVertexFit *	instance ()
Private Member Functions
void	updateMatrices (const HepVector helix, const HepSymMatrix err)
	FastVertexFit ()
Private Attributes
std::vector< HepMatrix >	m_D
std::vector< HepSymMatrix >	m_W
std::vector< HepSymMatrix >	m_DTWD
std::vector< HepVector >	m_xp
double	m_chisq
VertexParameter	m_vtx_infit
HepVector	m_Vx
HepSymMatrix	m_Evx
Static Private Attributes
static FastVertexFit *	m_pointer = 0

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Detailed Description

Definition at line 18 of file FastVertexFit.h.

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Constructor & Destructor Documentation

FastVertexFit::~FastVertexFit

(

)

Definition at line 15 of file FastVertexFit.cxx.

{;}

FastVertexFit::FastVertexFit

(

)

[private]

Definition at line 17 of file FastVertexFit.cxx.

Referenced by instance().

{;}

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Member Function Documentation

void FastVertexFit::addTrack	(	const int	number,
		const HepVector	helix,
		const HepSymMatrix	err
	)

Definition at line 29 of file FastVertexFit.cxx.

References alpha, cos(), VertexFitBField::getBFieldZRef(), VertexFitBField::instance(), m_D, m_DTWD, m_W, m_xp, and sin().

Referenced by DQASelHadron::execute().

                                                                                            {
  int ifail;
  int ierr;
  //HepSymMatrix err0(5, 0); //inverse of err;
  //err0 = err.inverse(ifail);
  HepSymMatrix Wc(2, 0);
  Wc[0][0] = err[0][0];
  Wc[0][1] = Wc[1][0] = err[0][3];
  Wc[1][1] = err[3][3];
  Wc = Wc.inverse(ifail);

  HepVector p0(3, 0), v0(3, 0);
  double pxy = 1./fabs(helix[2]);
  p0[0] = 0 - pxy*sin(helix[1]); //px
  p0[1] = pxy*cos(helix[1]);     //py
  p0[2] = pxy * helix[4];        //pz
  v0[0] = helix[0]*cos(helix[1]);//x
  v0[1] = helix[0]*sin(helix[1]);//y
  v0[2] = helix[3];              //z  

  HepPoint3D vv0(v0[0], v0[1], v0[2]);
  double bField = VertexFitBField::instance()->getBFieldZRef();

  int charge = (helix[2]>0 ? +1 :-1);
  double a = alpha * bField * charge;
  double T0 = sqrt((p0[0]+a*p0[1])*(p0[0]+a*p0[1])+(p0[1]-a*p0[0])*(p0[1]-a*p0[0]));

  HepMatrix Dc(2, 3, 0);
  Dc[0][0] = (p0[1] - a*v0[0])/T0;
  Dc[0][1] = 0 - (p0[0] + a*v0[1])/T0;
  Dc[1][0] = 0 - (p0[2]/T0) * (p0[0] + a*v0[1])/T0;
  Dc[1][1] = 0 - (p0[2]/T0) * (p0[1] - a*v0[0])/T0;
  Dc[1][2] = 1;

  m_D.push_back(Dc);
  m_W.push_back(Wc);

  HepSymMatrix DTWD(3, 0);
  DTWD = Wc.similarity(Dc.T());
  HepVector qTrk(2, 0);
  qTrk[0] = helix[0];
  qTrk[1] = helix[3];
  //HepVector xp(3, 0);
  //xp = Dc.inverse(ierr) * qTrk;
  m_DTWD.push_back(DTWD);
  m_xp.push_back(v0);
}

double FastVertexFit::chisq

(

)

const [inline]

Definition at line 38 of file FastVertexFit.h.

References m_chisq.

Referenced by Fit().

{return m_chisq;}

HepSymMatrix FastVertexFit::Evx

(

)

const [inline]

Definition at line 41 of file FastVertexFit.h.

References m_Evx.

{return m_Evx;}   

bool FastVertexFit::Fit

(

)

Definition at line 77 of file FastVertexFit.cxx.

References chisq(), genRecEmupikp::i, m_chisq, m_DTWD, m_Evx, m_Vx, m_xp, and T.

Referenced by DQASelHadron::execute().

                        {
  bool fitResult = false;

  int ifail;
  HepSymMatrix total_DTWD(3, 0);
  HepVector total_xp(3, 0);

  for(int i = 0; i < m_DTWD.size(); i++) {
    total_DTWD += m_DTWD[i];  
    total_xp += m_DTWD[i]*m_xp[i]; 
  }
  m_Vx = total_DTWD.inverse(ifail) * total_xp;
  m_Evx = total_DTWD.inverse(ifail);

  double chisq = 0;
  for(int i = 0; i < m_xp.size(); i++) {
    double chi2 = (m_DTWD[i].similarity((m_xp[i] - m_Vx).T()))[0][0];  
    chisq += chi2;
  }
  m_chisq = chisq;

  fitResult = true;
  return fitResult;
}

void FastVertexFit::init

(

)

Definition at line 19 of file FastVertexFit.cxx.

References m_chisq, m_D, m_DTWD, m_Evx, m_Vx, m_W, and m_xp.

Referenced by DQASelHadron::execute().

                         {
  m_D.clear();
  m_W.clear();
  m_DTWD.clear();
  m_xp.clear();
  m_chisq = 999;
  m_Vx = HepVector(3, 0);
  m_Evx = HepSymMatrix(3,0);
}

FastVertexFit * FastVertexFit::instance

(

)

[static]

Definition at line 9 of file FastVertexFit.cxx.

References FastVertexFit(), and m_pointer.

Referenced by DQASelHadron::execute().

                                        {
  if(m_pointer) return m_pointer;
  m_pointer = new FastVertexFit();
  return m_pointer;
}

HepVector FastVertexFit::Pull

(

)

const

Definition at line 102 of file FastVertexFit.cxx.

References m_Evx, and m_Vx.

                                    {
  HepVector pull(3, 0);
  pull[0] = m_Vx[0]/sqrt(m_Evx[0][0]);
  pull[1] = m_Vx[1]/sqrt(m_Evx[1][1]);
  pull[2] = m_Vx[2]/sqrt(m_Evx[2][2]);
  return pull;
}

void FastVertexFit::updateMatrices	(	const HepVector	helix,
		const HepSymMatrix	err
	)			[private]

VertexParameter FastVertexFit::vtx

(

)

const [inline]

Definition at line 39 of file FastVertexFit.h.

References m_vtx_infit.

{return m_vtx_infit;}

HepVector FastVertexFit::Vx

(

)

const [inline]

Definition at line 40 of file FastVertexFit.h.

References m_Vx.

Referenced by DQASelHadron::execute().

{return m_Vx;}

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Member Data Documentation

double FastVertexFit::m_chisq [private]

Definition at line 54 of file FastVertexFit.h.

Referenced by chisq(), Fit(), and init().

std::vector<HepMatrix> FastVertexFit::m_D [private]

Definition at line 48 of file FastVertexFit.h.

Referenced by addTrack(), and init().

std::vector<HepSymMatrix> FastVertexFit::m_DTWD [private]

Definition at line 50 of file FastVertexFit.h.

Referenced by addTrack(), Fit(), and init().

HepSymMatrix FastVertexFit::m_Evx [private]

Definition at line 57 of file FastVertexFit.h.

Referenced by Evx(), Fit(), init(), and Pull().

FastVertexFit * FastVertexFit::m_pointer = 0 [static, private]

Definition at line 61 of file FastVertexFit.h.

Referenced by instance().

VertexParameter FastVertexFit::m_vtx_infit [private]

Definition at line 55 of file FastVertexFit.h.

Referenced by vtx().

HepVector FastVertexFit::m_Vx [private]

Definition at line 56 of file FastVertexFit.h.

Referenced by Fit(), init(), Pull(), and Vx().

std::vector<HepSymMatrix> FastVertexFit::m_W [private]

Definition at line 49 of file FastVertexFit.h.

Referenced by addTrack(), and init().

std::vector<HepVector> FastVertexFit::m_xp [private]

Definition at line 51 of file FastVertexFit.h.

Referenced by addTrack(), Fit(), and init().

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