CMS 3D CMS Logo

CollinearFitAtTM Class Reference

Constrained fit at a TrajectoryMeasurement assuming collinearity of incoming / outgoing momenta. More...

#include <RecoParticleFlow/PFTracking/interface/CollinearFitAtTM.h>

List of all members.

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

 CollinearFitAtTM ()
bool fit (const AlgebraicVector5 &fwdParameters, const AlgebraicSymMatrix55 &fwdCovariance, const AlgebraicVector5 &bwdParameters, const AlgebraicSymMatrix55 &bwdCovariance, const LocalPoint &hitPosition, const LocalError &hitErrors, ResultVector &parameters, ResultMatrix &covariance, double &chi2)
 Fit with explicit input parameters. Return value "true" for success.
bool fit (const TrajectoryMeasurement &tm, ResultVector &parameters, ResultMatrix &covariance, double &chi2)
 Fit for one TM. Return value "true" for success.

Private Attributes

ROOT::Math::SMatrix< double, 12, 6 > jacobian_
ROOT::Math::SVector< double, 12 > measurements_
ROOT::Math::SVector< double, 6 > projectedMeasurements_
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 17 of file CollinearFitAtTM.h.

Member Typedef Documentation

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

Definition at line 25 of file CollinearFitAtTM.h.

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

Definition at line 24 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 20 of file CollinearFitAtTM.h.

00020 { ParQpIn=0, ParQpOut, ParDxDz, ParDyDz, ParX, ParY };

Constructor & Destructor Documentation

CollinearFitAtTM::CollinearFitAtTM (  ) 

Definition at line 4 of file CollinearFitAtTM.cc.

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

00005 {
00006   //
00007   // Jacobian
00008   //
00009   for ( int i=0; i<12; ++i ) {
00010     for ( int j=0; j<6; ++j )  jacobian_(i,j) = 0;
00011   }
00012   for ( int i=1; i<5; ++i ) {
00013     jacobian_(i,ParQpOut+i) = jacobian_(i+5,ParQpOut+i) = 1;
00014   }
00015   jacobian_(0,ParQpIn) = 1.;
00016   jacobian_(5,ParQpOut) = 1.;
00017 }

Member Function Documentation

bool CollinearFitAtTM::fit ( const AlgebraicVector5 &  fwdParameters,
const AlgebraicSymMatrix55 &  fwdCovariance,
const AlgebraicVector5 &  bwdParameters,
const AlgebraicSymMatrix55 &  bwdCovariance,
const LocalPoint &  hitPosition,
const LocalError &  hitErrors,
ResultVector &  parameters,
ResultMatrix &  covariance,
double &  chi2 
)

Fit with explicit input parameters. Return value "true" for success.

Definition at line 55 of file CollinearFitAtTM.cc.

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

00062 {
00063 
00064   if ( hitErr.xx()>0 )
00065     jacobian_(10,ParX) = jacobian_(11,ParY) = 1;
00066   else
00067     jacobian_(10,ParX) = jacobian_(11,ParY) = 0;
00068 
00069   for ( int i=0; i<12; ++i ) {
00070     for ( int j=0; j<12; ++j )  weightMatrix_(i,j) = 0;
00071   }
00072 
00073   for ( int i=0; i<5; ++i )  measurements_(i) = fwdParameters(i);
00074   weightMatrix_.Place_at(fwdCovariance,0,0);
00075   for ( int i=0; i<5; ++i )  measurements_(i+5) = bwdParameters(i);
00076   weightMatrix_.Place_at(bwdCovariance,5,5);
00077   if ( hitErr.xx()>0 ) {
00078     measurements_(10) = hitPos.x();
00079     measurements_(11) = hitPos.y();
00080     weightMatrix_(10,10) = hitErr.xx();
00081     weightMatrix_(10,11) = weightMatrix_(11,10) = hitErr.xy();
00082     weightMatrix_(11,11) = hitErr.yy();
00083   }
00084   else {
00085     measurements_(10) = measurements_(11) = 0.;
00086     weightMatrix_(10,10) = weightMatrix_(11,11) = 1.;
00087     weightMatrix_(10,11) = weightMatrix_(11,10) = 0.;
00088   }
00089   //
00090   // invert covariance matrix
00091   //
00092   if ( !weightMatrix_.Invert() ) {
00093     edm::LogWarning("CollinearFitAtTM") << "Inversion of input covariance matrix failed";
00094     return false;
00095   }
00096 
00097   //
00098   projectedMeasurements_ = ROOT::Math::Transpose(jacobian_)*(weightMatrix_*measurements_);
00099   //
00100   // Fitted parameters and covariance matrix
00101   // 
00102   covariance = ROOT::Math::SimilarityT(jacobian_,weightMatrix_);
00103   if ( !covariance.Invert() ) {
00104     edm::LogWarning("CollinearFitAtTM") << "Inversion of resulting weight matrix failed";
00105     return false;
00106   }
00107 
00108   parameters = covariance*projectedMeasurements_;
00109 
00110   //
00111   // chi2
00112   //
00113   chi2 = ROOT::Math::Similarity(measurements_,weightMatrix_) -
00114     ROOT::Math::Similarity(projectedMeasurements_,covariance);
00115 
00116   return true;
00117 }

bool CollinearFitAtTM::fit ( const TrajectoryMeasurement &  tm,
ResultVector &  parameters,
ResultMatrix &  covariance,
double &  chi2 
)

Fit for one TM. Return value "true" for success.

Definition at line 20 of file CollinearFitAtTM.cc.

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

Referenced by PFGsfHelper::PFGsfHelper().

00024 {
00025   //
00026   // check input
00027   //
00028   if ( !tm.forwardPredictedState().isValid() ||
00029        !tm.backwardPredictedState().isValid() ||
00030        !tm.updatedState().isValid() ) {
00031     edm::LogWarning("CollinearFitAtTM") << "Invalid state in TrajectoryMeasurement";
00032     return false;
00033   }
00034   //
00035   // prepare fit
00036   //
00037   AlgebraicVector5 fwdPar = tm.forwardPredictedState().localParameters().vector();
00038   AlgebraicSymMatrix55 fwdCov = tm.forwardPredictedState().localError().matrix();
00039   AlgebraicVector5 bwdPar = tm.backwardPredictedState().localParameters().vector();
00040   AlgebraicSymMatrix55 bwdCov = tm.backwardPredictedState().localError().matrix();
00041 
00042   LocalPoint hitPos(0.,0.,0.);
00043   LocalError hitErr(-1.,-1.,-1.);
00044   if ( tm.recHit()->isValid() ) {
00045     hitPos = tm.recHit()->localPosition();
00046     hitErr = tm.recHit()->localPositionError();
00047   }
00048 
00049   return fit(fwdPar,fwdCov,bwdPar,bwdCov,
00050              hitPos,hitErr,
00051              parameters,covariance,chi2);
00052 }

Member Data Documentation

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

Definition at line 41 of file CollinearFitAtTM.h.

Referenced by CollinearFitAtTM(), and fit().

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

Definition at line 42 of file CollinearFitAtTM.h.

Referenced by fit().

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

Definition at line 44 of file CollinearFitAtTM.h.

Referenced by fit().

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

Definition at line 43 of file CollinearFitAtTM.h.

Referenced by fit().

The documentation for this class was generated from the following files:
Generated on Tue Jun 9 18:16:28 2009 for CMSSW by  doxygen 1.5.4