#include <CollinearFitAtTM.h>

Public Types
enum	{ ParQpIn = 0, ParQpOut, ParDxDz, ParDyDz, ParX, ParY }
	parameter indices in the result vector / covariance matrix More...
typedef ROOT::Math::SMatrix < double, 6, 6, ROOT::Math::MatRepSym < double, 6 > >	ResultMatrix
typedef ROOT::Math::SVector < double, 6 >	ResultVector
Public Member Functions
double	chi2 () const
	chi2
	CollinearFitAtTM2 (const TrajectoryMeasurement &tm)
	CollinearFitAtTM2 (const AlgebraicVector5 &fwdParameters, const AlgebraicSymMatrix55 &fwdCovariance, const AlgebraicVector5 &bwdParameters, const AlgebraicSymMatrix55 &bwdCovariance, const LocalPoint &hitPosition, const LocalError &hitErrors)
const ResultMatrix &	covariance () const
	covariance matrix of fitted parameters
Measurement1D	deltaP () const
	estimated deltaP (out-in) from fit parameters
int	ndof () const
	degrees of freedom
const ResultVector &	parameters () const
	vector of fitted parameters
bool	valid () const
	status of the fit
Private Member Functions
bool	fit (const AlgebraicVector5 &fwdParameters, const AlgebraicSymMatrix55 &fwdCovariance, const AlgebraicVector5 &bwdParameters, const AlgebraicSymMatrix55 &bwdCovariance, const LocalPoint &hitPosition, const LocalError &hitErrors)
	Perform the fit. Return value "true" for success.
void	initJacobian ()
	initialise the jacobian
Private Attributes
double	chi2_
ResultMatrix	covariance_
ROOT::Math::SMatrix< double, 12, 6 >	jacobian_
ROOT::Math::SVector< double, 12 >	measurements_
int	ndof_
ResultVector	parameters_
ROOT::Math::SVector< double, 6 >	projectedMeasurements_
bool	valid_
ROOT::Math::SMatrix< double, 12, 12, ROOT::Math::MatRepSym < double, 12 > >	weightMatrix_

Detailed Description

Constrained fit at a TrajectoryMeasurement assuming collinearity of incoming / outgoing momenta. The result of the fit is a vector of 6 variables: the first five correspond to local trajectory parameters for the incoming momentum, the 6th is the estimated remaining energy fraction (p_out / p_in). The NDF are 6 (4) for a valid (invalid) RecHit.

Definition at line 18 of file CollinearFitAtTM.h.

Member Typedef Documentation

typedef ROOT::Math::SMatrix<double,6,6,ROOT::Math::MatRepSym<double,6> > CollinearFitAtTM2::ResultMatrix

Definition at line 32 of file CollinearFitAtTM.h.

typedef ROOT::Math::SVector<double,6> CollinearFitAtTM2::ResultVector

Definition at line 31 of file CollinearFitAtTM.h.

Member Enumeration Documentation

anonymous enum

parameter indices in the result vector / covariance matrix

Enumerator:

ParQpIn
ParQpOut
ParDxDz
ParDyDz
ParX
ParY

Definition at line 21 of file CollinearFitAtTM.h.

{ ParQpIn=0, ParQpOut, ParDxDz, ParDyDz, ParX, ParY };

Constructor & Destructor Documentation

CollinearFitAtTM2::CollinearFitAtTM2 ( const TrajectoryMeasurement & tm )

Definition at line 4 of file CollinearFitAtTM.cc.

References TrajectoryMeasurement::backwardPredictedState(), fit(), TrajectoryMeasurement::forwardPredictedState(), initJacobian(), TrajectoryStateOnSurface::isValid(), TrajectoryStateOnSurface::localError(), TrajectoryStateOnSurface::localParameters(), LocalTrajectoryError::matrix(), TrajectoryMeasurement::recHit(), TrajectoryMeasurement::updatedState(), and LocalTrajectoryParameters::vector().

                                                                     : 
  valid_(false),chi2_(-1),ndof_(-1) {
  //
  // check input
  //
  if ( !tm.forwardPredictedState().isValid() ||
       !tm.backwardPredictedState().isValid() ||
       !tm.updatedState().isValid() ) {
    edm::LogWarning("CollinearFitAtTM2") << "Invalid state in TrajectoryMeasurement";
    return;
  }
  //
  // prepare fit
  //
  initJacobian();
  AlgebraicVector5 fwdPar = tm.forwardPredictedState().localParameters().vector();
  AlgebraicSymMatrix55 fwdCov = tm.forwardPredictedState().localError().matrix();
  AlgebraicVector5 bwdPar = tm.backwardPredictedState().localParameters().vector();
  AlgebraicSymMatrix55 bwdCov = tm.backwardPredictedState().localError().matrix();

  LocalPoint hitPos(0.,0.,0.);
  LocalError hitErr(-1.,-1.,-1.);
  if ( tm.recHit()->isValid() ) {
    hitPos = tm.recHit()->localPosition();
    hitErr = tm.recHit()->localPositionError();
  }

  fit(fwdPar,fwdCov,bwdPar,bwdCov,hitPos,hitErr);
}

CollinearFitAtTM2::CollinearFitAtTM2	(	const AlgebraicVector5 &	fwdParameters,
		const AlgebraicSymMatrix55 &	fwdCovariance,
		const AlgebraicVector5 &	bwdParameters,
		const AlgebraicSymMatrix55 &	bwdCovariance,
		const LocalPoint &	hitPosition,
		const LocalError &	hitErrors
	)

Definition at line 34 of file CollinearFitAtTM.cc.

References fit(), and initJacobian().

                                                                 : 
  valid_(false),chi2_(-1),ndof_(-1) {
  //
  // prepare fit
  //
  initJacobian();

  fit(fwdParameters,fwdCovariance,bwdParameters,bwdCovariance,hitPosition,hitErrors);
}

Member Function Documentation

double CollinearFitAtTM2::chi2 ( void ) const [inline]

chi2

Definition at line 36 of file CollinearFitAtTM.h.

References chi2_.

{return chi2_;}

const ResultMatrix& CollinearFitAtTM2::covariance ( void ) const [inline]

covariance matrix of fitted parameters

Definition at line 42 of file CollinearFitAtTM.h.

References covariance_.

{return covariance_;}

Measurement1D CollinearFitAtTM2::deltaP ( ) const

estimated deltaP (out-in) from fit parameters

Definition at line 131 of file CollinearFitAtTM.cc.

References covariance_, parameters_, mathSSE::sqrt(), and valid_.

Referenced by GsfTrackProducerBase::computeModeAtTM().

                                 {
  //
  // check validity
  //
  if ( !valid_ )  return Measurement1D();
  //
  // deltaP = 1/qpout - 1/qpin ; uncertainty from linear error propagation
  //
  double qpIn = parameters_(0);
  double sig2In = covariance_(0,0);
  double qpOut = parameters_(1);
  double sig2Out = covariance_(1,1);
  double corrInOut = covariance_(0,1);
  double pIn = 1./fabs(qpIn);
  double pOut = 1./fabs(qpOut);
  double sig2DeltaP = pIn/qpIn*pIn/qpIn*sig2In - 2*pIn/qpIn*pOut/qpOut*corrInOut + 
    pOut/qpOut*pOut/qpOut*sig2Out;

  return Measurement1D(pOut-pIn,sig2DeltaP?sqrt(sig2DeltaP):0.);
}

bool CollinearFitAtTM2::fit	(	const AlgebraicVector5 &	fwdParameters,
		const AlgebraicSymMatrix55 &	fwdCovariance,
		const AlgebraicVector5 &	bwdParameters,
		const AlgebraicSymMatrix55 &	bwdCovariance,
		const LocalPoint &	hitPosition,
		const LocalError &	hitErrors
	)		`[private]`

Perform the fit. Return value "true" for success.

Definition at line 66 of file CollinearFitAtTM.cc.

References chi2_, covariance_, i, j, jacobian_, measurements_, ndof_, parameters_, ParX, ParY, projectedMeasurements_, valid_, weightMatrix_, PV3DBase< T, PVType, FrameType >::x(), LocalError::xx(), LocalError::xy(), PV3DBase< T, PVType, FrameType >::y(), and LocalError::yy().

Referenced by CollinearFitAtTM2().

{

  if ( hitErr.xx()>0 )
    jacobian_(10,ParX) = jacobian_(11,ParY) = 1;
  else
    jacobian_(10,ParX) = jacobian_(11,ParY) = 0;

  for ( int i=0; i<12; ++i ) {
    for ( int j=0; j<12; ++j )  weightMatrix_(i,j) = 0;
  }

  for ( int i=0; i<5; ++i )  measurements_(i) = fwdParameters(i);
  weightMatrix_.Place_at(fwdCovariance,0,0);
  for ( int i=0; i<5; ++i )  measurements_(i+5) = bwdParameters(i);
  weightMatrix_.Place_at(bwdCovariance,5,5);
  if ( hitErr.xx()>0 ) {
    measurements_(10) = hitPos.x();
    measurements_(11) = hitPos.y();
    weightMatrix_(10,10) = hitErr.xx();
    weightMatrix_(10,11) = weightMatrix_(11,10) = hitErr.xy();
    weightMatrix_(11,11) = hitErr.yy();
  }
  else {
    measurements_(10) = measurements_(11) = 0.;
    weightMatrix_(10,10) = weightMatrix_(11,11) = 1.;
    weightMatrix_(10,11) = weightMatrix_(11,10) = 0.;
  }
  //
  // invert covariance matrix
  //
  if ( !weightMatrix_.Invert() ) {
    edm::LogWarning("CollinearFitAtTM2") << "Inversion of input covariance matrix failed";
    return false;
  }

  //
  projectedMeasurements_ = ROOT::Math::Transpose(jacobian_)*(weightMatrix_*measurements_);
  //
  // Fitted parameters and covariance matrix
  // 
  covariance_ = ROOT::Math::SimilarityT(jacobian_,weightMatrix_);
  if ( !covariance_.Invert() ) {
    edm::LogWarning("CollinearFitAtTM2") << "Inversion of resulting weight matrix failed";
    return false;
  }

  parameters_ = covariance_*projectedMeasurements_;

  //
  // chi2
  //
  chi2_ = ROOT::Math::Similarity(measurements_,weightMatrix_) -
    ROOT::Math::Similarity(projectedMeasurements_,covariance_);
  ndof_ =  hitErr.xx()>0 ? 6 : 4;

  valid_ = true;
  return true;
}

void CollinearFitAtTM2::initJacobian ( ) [private]

initialise the jacobian

Definition at line 50 of file CollinearFitAtTM.cc.

References i, j, jacobian_, ParQpIn, and ParQpOut.

Referenced by CollinearFitAtTM2().

{
  //
  // Jacobian
  //
  for ( int i=0; i<12; ++i ) {
    for ( int j=0; j<6; ++j )  jacobian_(i,j) = 0;
  }
  for ( int i=1; i<5; ++i ) {
    jacobian_(i,ParQpOut+i) = jacobian_(i+5,ParQpOut+i) = 1;
  }
  jacobian_(0,ParQpIn) = 1.;
  jacobian_(5,ParQpOut) = 1.;
}

int CollinearFitAtTM2::ndof ( ) const [inline]

degrees of freedom

Definition at line 38 of file CollinearFitAtTM.h.

References ndof_.

{return ndof_;}

const ResultVector& CollinearFitAtTM2::parameters ( void ) const [inline]

vector of fitted parameters

Definition at line 40 of file CollinearFitAtTM.h.

References parameters_.

{return parameters_;}

bool CollinearFitAtTM2::valid ( ) const [inline]

status of the fit

Definition at line 34 of file CollinearFitAtTM.h.

References valid_.

{return valid_;}

Member Data Documentation

double CollinearFitAtTM2::chi2_ [private]

Definition at line 66 of file CollinearFitAtTM.h.

Referenced by chi2(), and fit().

ResultMatrix CollinearFitAtTM2::covariance_ [private]

Definition at line 65 of file CollinearFitAtTM.h.

Referenced by covariance(), deltaP(), and fit().

ROOT::Math::SMatrix<double,12,6> CollinearFitAtTM2::jacobian_ [private]

Definition at line 57 of file CollinearFitAtTM.h.

Referenced by fit(), and initJacobian().

ROOT::Math::SVector<double,12> CollinearFitAtTM2::measurements_ [private]

Definition at line 58 of file CollinearFitAtTM.h.

Referenced by fit().

int CollinearFitAtTM2::ndof_ [private]

Definition at line 67 of file CollinearFitAtTM.h.

Referenced by fit(), and ndof().

ResultVector CollinearFitAtTM2::parameters_ [private]

Definition at line 64 of file CollinearFitAtTM.h.

Referenced by deltaP(), fit(), and parameters().

ROOT::Math::SVector<double,6> CollinearFitAtTM2::projectedMeasurements_ [private]

Definition at line 60 of file CollinearFitAtTM.h.

Referenced by fit().

bool CollinearFitAtTM2::valid_ [private]

Definition at line 63 of file CollinearFitAtTM.h.

Referenced by deltaP(), fit(), and valid().

ROOT::Math::SMatrix<double,12,12,ROOT::Math::MatRepSym<double,12> > CollinearFitAtTM2::weightMatrix_ [private]

Definition at line 59 of file CollinearFitAtTM.h.

Referenced by fit().

CollinearFitAtTM2 Class Reference

Public Types

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Typedef Documentation

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation