CollinearFitAtTM2 Class Reference

#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 More...
	CollinearFitAtTM2 (const AlgebraicVector5 &fwdParameters, const AlgebraicSymMatrix55 &fwdCovariance, const AlgebraicVector5 &bwdParameters, const AlgebraicSymMatrix55 &bwdCovariance, const LocalPoint &hitPosition, const LocalError &hitErrors)
	CollinearFitAtTM2 (const TrajectoryMeasurement &tm)
const ResultMatrix &	covariance () const
	covariance matrix of fitted parameters More...
Measurement1D	deltaP () const
	estimated deltaP (out-in) from fit parameters More...
int	ndof () const
	degrees of freedom More...
const ResultVector &	parameters () const
	vector of fitted parameters More...
bool	valid () const
	status of the fit More...

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. More...
void	initJacobian ()
	initialise the jacobian More...

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

ResultMatrix

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

Definition at line 32 of file CollinearFitAtTM.h.

ResultVector

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

Definition at line 31 of file CollinearFitAtTM.h.

Member Enumeration Documentation

anonymous enum

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() [1/2]

CollinearFitAtTM2::CollinearFitAtTM2

(

const TrajectoryMeasurement &

tm

)

Definition at line 4 of file CollinearFitAtTM.cc.

                                                                    : 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);
}

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

CollinearFitAtTM2() [2/2]

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

Definition at line 31 of file CollinearFitAtTM.cc.

    : valid_(false), chi2_(-1), ndof_(-1) {
  //
  // prepare fit
  //
  initJacobian();
 
  fit(fwdParameters, fwdCovariance, bwdParameters, bwdCovariance, hitPosition, hitErrors);
}

References fit(), and initJacobian().

Member Function Documentation

chi2()

double CollinearFitAtTM2::chi2 ( void  ) const

inline

chi2

Definition at line 36 of file CollinearFitAtTM.h.

{ return chi2_; }

References chi2_.

covariance()

const ResultMatrix& CollinearFitAtTM2::covariance ( void  ) const

inline

covariance matrix of fitted parameters

Definition at line 42 of file CollinearFitAtTM.h.

{ return covariance_; }

References covariance_.

deltaP()

Measurement1D CollinearFitAtTM2::deltaP

(

)

const

estimated deltaP (out-in) from fit parameters

Definition at line 126 of file CollinearFitAtTM.cc.

                                              {
  //
  // 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.);
}

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

Referenced by GsfTrackProducerBase::computeModeAtTM().

fit()

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 61 of file CollinearFitAtTM.cc.

                                                      {
  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;
}

References chi2_, covariance_, mps_fire::i, dqmiolumiharvest::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(), and trackingPlots.Iteration::modules().

initJacobian()

void CollinearFitAtTM2::initJacobian ( )

private

initialise the jacobian

Definition at line 46 of file CollinearFitAtTM.cc.

                                     {
  //
  // 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.;
}

References mps_fire::i, dqmiolumiharvest::j, jacobian_, ParQpIn, and ParQpOut.

Referenced by CollinearFitAtTM2().

ndof()

int CollinearFitAtTM2::ndof ( void  ) const

inline

degrees of freedom

Definition at line 38 of file CollinearFitAtTM.h.

{ return ndof_; }

References ndof_.

parameters()

const ResultVector& CollinearFitAtTM2::parameters ( void  ) const

inline

vector of fitted parameters

Definition at line 40 of file CollinearFitAtTM.h.

{ return parameters_; }

References parameters_.

valid()

bool CollinearFitAtTM2::valid ( ) const

inline

status of the fit

Definition at line 34 of file CollinearFitAtTM.h.

{ return valid_; }

References valid_.

Member Data Documentation

chi2_

double CollinearFitAtTM2::chi2_

private

Definition at line 67 of file CollinearFitAtTM.h.

Referenced by chi2(), and fit().

covariance_

ResultMatrix CollinearFitAtTM2::covariance_

private

Definition at line 66 of file CollinearFitAtTM.h.

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

jacobian_

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

private

Definition at line 58 of file CollinearFitAtTM.h.

Referenced by fit(), and initJacobian().

measurements_

ROOT::Math::SVector<double, 12> CollinearFitAtTM2::measurements_

private

Definition at line 59 of file CollinearFitAtTM.h.

Referenced by fit().

ndof_

int CollinearFitAtTM2::ndof_

private

Definition at line 68 of file CollinearFitAtTM.h.

Referenced by fit(), and ndof().

parameters_

ResultVector CollinearFitAtTM2::parameters_

private

Definition at line 65 of file CollinearFitAtTM.h.

Referenced by Mixins._TypedParameterizable::clone(), Types.PSet::clone(), Types.EDAlias::clone(), Mixins._TypedParameterizable::copy(), deltaP(), fit(), and parameters().

projectedMeasurements_

ROOT::Math::SVector<double, 6> CollinearFitAtTM2::projectedMeasurements_

private

Definition at line 61 of file CollinearFitAtTM.h.

Referenced by fit().

valid_

bool CollinearFitAtTM2::valid_

private

Definition at line 64 of file CollinearFitAtTM.h.

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

weightMatrix_

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

private

Definition at line 60 of file CollinearFitAtTM.h.

Referenced by fit().