Chi2StripEstimator Class Reference

#include <Chi2StripEstimator.h>

Inheritance diagram for Chi2StripEstimator:

List of all members.

Public Member Functions
	Chi2StripEstimator (double maxChi2, double nSigma=3.)
virtual Chi2StripEstimator *	clone () const
virtual std::pair< bool, double >	estimate (const TrajectoryStateOnSurface &, const TransientTrackingRecHit &) const

---

Detailed Description

A Chi2 MeasurementEstimator that works in the measurement (strip) frame and uses both coordinates of a hit. Ported from ORCA.

Date:

2007/05/09 14:05:13

Revision:

1.2

Author:

todorov, cerati

Definition at line 15 of file Chi2StripEstimator.h.

---

Constructor & Destructor Documentation

Chi2StripEstimator::Chi2StripEstimator	(	double	maxChi2,
		double	nSigma = 3.
	)		[inline, explicit]

Definition at line 18 of file Chi2StripEstimator.h.

Referenced by clone().

                                                                  : 
    Chi2MeasurementEstimatorBase( maxChi2, nSigma) {}

---

Member Function Documentation

virtual Chi2StripEstimator* Chi2StripEstimator::clone

(

void

)

const [inline, virtual]

Implements MeasurementEstimator.

Definition at line 24 of file Chi2StripEstimator.h.

References Chi2StripEstimator().

                                            {
    return new Chi2StripEstimator(*this);
  }

pair< bool, double > Chi2StripEstimator::estimate	(	const TrajectoryStateOnSurface &	ts,
		const TransientTrackingRecHit &	hit
	)		const [virtual]

Returns pair( true, value) if the TrajectoryStateOnSurface is compatible with the RecHit, and pair( false, value) if it is not compatible. The TrajectoryStateOnSurface must be on the same Surface as the RecHit. For an estimator where there is no value computed, e.g. fixed window estimator, only the first(bool) part is of interest.

Implements Chi2MeasurementEstimatorBase.

Definition at line 11 of file Chi2StripEstimator.cc.

References funct::C, TransientTrackingRecHit::detUnit(), invertPosDefMatrix(), GeomDetType::isTrackerPixel(), TrajectoryStateOnSurface::localError(), TrackingRecHit::localPosition(), TrajectoryStateOnSurface::localPosition(), TrackingRecHit::localPositionError(), m, max(), Topology::measurementError(), Topology::measurementPosition(), LocalTrajectoryError::positionError(), dttmaxenums::R, alignCSCRings::r, GeomDetUnit::topology(), GeomDetUnit::type(), MeasurementError::uu(), MeasurementError::uv(), MeasurementError::vv(), PV2DBase< T, PVType, FrameType >::x(), x, and PV2DBase< T, PVType, FrameType >::y().

Referenced by Chi2SwitchingEstimator::estimate().

                                                                       {

  if(//hit.isMatched() || 
     hit.detUnit()->type().isTrackerPixel()) {
    return HitReturnType(false,0);
  }

  const StripTopology* topology = 
    dynamic_cast<const StripTopology*>(&(hit.detUnit()->topology())); 

  MeasurementPoint mp;
  MeasurementError me;

  AlgebraicVector2 m;
  mp = topology->measurementPosition(hit.localPosition());
  m[0] = mp.x();
  m[1] = mp.y();
  
  AlgebraicSymMatrix22 V;
  me = topology->measurementError(hit.localPosition(),
                                  hit.localPositionError());
 
  V(0,0) = me.uu();
  V(1,0) = me.uv();
  V(1,1) = me.vv();

  AlgebraicVector2 x;
  mp = topology->measurementPosition(state.localPosition());
  m[0] = mp.x();
  m[1] = mp.y();
  
  AlgebraicSymMatrix22 C;
  me = topology->measurementError(state.localPosition(),
                                  state.localError().positionError());
  C(0,0) = me.uu();
  C(1,0) = me.uv();
  C(1,1) = me.vv();

  AlgebraicVector2 r(m - x);
  AlgebraicSymMatrix22 R(V+C);
  bool ierr =  !invertPosDefMatrix(R);
  if (ierr) {
    edm::LogError("Chi2StripEstimator")<<" could not invert matrix:\n"<<(V+C);
    return returnIt( 0.0 );
  }

  double est = max(ROOT::Math::Similarity(r, R), 0.000001); // avoid exact zero

  return returnIt( est);
}