KFBasedPixelFitter Class Reference

#include <KFBasedPixelFitter.h>

Inheritance diagram for KFBasedPixelFitter:

Classes
class	MyBeamSpotGeomDet
class	MyBeamSpotHit

Public Member Functions
	KFBasedPixelFitter (const edm::EventSetup *es, const Propagator *propagator, const Propagator *opropagator, const TransientTrackingRecHitBuilder *ttrhBuilder, const TrackerGeometry *tracker, const MagneticField *field, const reco::BeamSpot *beamSpot)
std::unique_ptr< reco::Track >	run (const std::vector< const TrackingRecHit * > &hits, const TrackingRegion &region) const override
	~KFBasedPixelFitter () override
Public Member Functions inherited from PixelFitterBase
virtual reco::Track *	run (const edm::EventSetup &es, const std::vector< const TrackingRecHit * > &hits, const TrackingRegion &region) const
virtual reco::Track *	run (const edm::Event &ev, const edm::EventSetup &es, const std::vector< const TrackingRecHit * > &hits, const TrackingRegion &region) const
virtual	~PixelFitterBase ()

Private Attributes
const reco::BeamSpot *	theBeamSpot
const edm::EventSetup *	theES
const MagneticField *	theField
const Propagator *	theOPropagator
const Propagator *	thePropagator
const TrackerGeometry *	theTracker
const TransientTrackingRecHitBuilder *	theTTRHBuilder

Detailed Description

Definition at line 22 of file KFBasedPixelFitter.h.

Constructor & Destructor Documentation

KFBasedPixelFitter::KFBasedPixelFitter	(	const edm::EventSetup *	es,
		const Propagator *	propagator,
		const Propagator *	opropagator,
		const TransientTrackingRecHitBuilder *	ttrhBuilder,
		const TrackerGeometry *	tracker,
		const MagneticField *	field,
		const reco::BeamSpot *	beamSpot
	)

Definition at line 78 of file KFBasedPixelFitter.cc.

                                                                    :
  theES(es), thePropagator(propagator), theOPropagator(opropagator), theTTRHBuilder(ttrhBuilder),
  theTracker(tracker), theField(field), theBeamSpot(beamSpot)
{}

KFBasedPixelFitter::~KFBasedPixelFitter ( )

inlineoverride

Definition at line 28 of file KFBasedPixelFitter.h.

References hfClusterShapes_cfi::hits, and findQualityFiles::run.

{}

Member Function Documentation

std::unique_ptr< reco::Track > KFBasedPixelFitter::run ( const std::vector< const TrackingRecHit * > &  hits, const TrackingRegion &  region  ) const

overridevirtual

Reimplemented from PixelFitterBase.

Definition at line 86 of file KFBasedPixelFitter.cc.

References TransientTrackingRecHitBuilder::build(), Plane::build(), patCaloMETCorrections_cff::C, CircleFromThreePoints::center(), ALCARECOTkAlJpsiMuMu_cff::charge, TrajectoryStateOnSurface::charge(), vertices_cff::chi2, funct::cos(), CircleFromThreePoints::curvature(), TrajectoryStateOnSurface::curvilinearError(), GlobalErrorBase< T, ErrorWeightType >::cxx(), GlobalErrorBase< T, ErrorWeightType >::czz(), TransverseImpactPointExtrapolator::extrapolate(), TrackingRecHit::geographicalId(), TrajectoryStateOnSurface::globalMomentum(), TrajectoryStateOnSurface::globalPosition(), TrackerGeometry::idToDet(), PixelRecoUtilities::inversePt(), TrajectoryStateOnSurface::isValid(), SiStripPI::max, ndof, nhits, TrackingRegion::origin(), TrackingRegion::originRBound(), TrackingRegion::originZBound(), PV3DBase< T, PVType, FrameType >::perp(), hiPixelPairStep_cff::points, GloballyPositioned< T >::position(), createTree::pp, Propagator::propagate(), ALCARECOTkAlBeamHalo_cff::ptMin, TrackingRegion::ptMin(), rpcPointValidation_cfi::recHit, TrajectoryStateOnSurface::rescaleError(), GloballyPositioned< T >::rotation(), funct::sin(), sqr(), GeomDet::surface(), TrajectoryStateOnSurface::surface(), funct::tan(), theBeamSpot, theES, theField, theOPropagator, thePropagator, PV3DBase< T, PVType, FrameType >::theta(), theta(), theTracker, theTTRHBuilder, GeomDet::toGlobal(), KFUpdator::update(), gsfElectronCkfTrackCandidateMaker_cff::updator, x, PV3DBase< T, PVType, FrameType >::x(), Basic2DVector< T >::x(), y, PV3DBase< T, PVType, FrameType >::y(), Basic2DVector< T >::y(), and PV3DBase< T, PVType, FrameType >::z().

                                                                                                                                  {
  std::unique_ptr<reco::Track> ret;

  int nhits = hits.size();
  if (nhits <2) return ret;


  float ptMin = region.ptMin();

  const GlobalPoint& vertexPos = region.origin();
  GlobalError vertexErr( sqr(region.originRBound()), 0, sqr(region.originRBound()), 0, 0, sqr(region.originZBound()));

  std::vector<GlobalPoint> points(nhits);
  points[0] = theTracker->idToDet(hits[0]->geographicalId())->toGlobal(hits[0]->localPosition());
  points[1] = theTracker->idToDet(hits[1]->geographicalId())->toGlobal(hits[1]->localPosition());
  points[2] = theTracker->idToDet(hits[2]->geographicalId())->toGlobal(hits[2]->localPosition());

  //
  //initial Kinematics
  //
  GlobalVector initMom;
  int charge;
  float theta;
  CircleFromThreePoints circle(points[0], points[1], points[2]);
  if (circle.curvature() > 1.e-4) {
    float invPt = PixelRecoUtilities::inversePt( circle.curvature(), *theES);
    float valPt = 1.f/invPt;
    float chargeTmp =    (points[1].x()-points[0].x())*(points[2].y()-points[1].y())
                       - (points[1].y()-points[0].y())*(points[2].x()-points[1].x()); 
    charge =  (chargeTmp>0) ? -1 : 1;
    float valPhi = (charge>0) ? std::atan2(circle.center().x(),-circle.center().y()) :  std::atan2(-circle.center().x(),circle.center().y());
    theta = GlobalVector(points[1]-points[0]).theta();
    initMom = GlobalVector(valPt*cos(valPhi), valPt*sin(valPhi), valPt/tan(theta)); 
  } 
  else {
    initMom = GlobalVector(points[1]-points[0]);
    initMom *= 10000./initMom.perp();
    charge = 1;
    theta = initMom.theta();
  }
  GlobalTrajectoryParameters initialKine(vertexPos, initMom, TrackCharge(charge), theField);

  //
  // initial error
  //
  AlgebraicSymMatrix55 C = ROOT::Math::SMatrixIdentity();
  float sin2th = sqr(sin(theta));
  float minC00 = 1.0;
  C[0][0] = std::max(sin2th/sqr(ptMin), minC00);
  float zErr = vertexErr.czz();
  float transverseErr = vertexErr.cxx(); // assume equal cxx cyy
  C[3][3] = transverseErr;
  C[4][4] = zErr*sin2th + transverseErr*(1-sin2th);
  CurvilinearTrajectoryError initialError(C);

  FreeTrajectoryState fts(initialKine, initialError);

  // get updator
  KFUpdator  updator;

  // Now update initial state track using information from hits.
  TrajectoryStateOnSurface outerState;
  DetId outerDetId = 0;
  const TrackingRecHit* hit = nullptr;
  for ( unsigned int iHit = 0; iHit < hits.size(); iHit++) {
    hit = hits[iHit];
    if (iHit==0) outerState = thePropagator->propagate(fts,theTracker->idToDet(hit->geographicalId())->surface());
    outerDetId = hit->geographicalId();
    TrajectoryStateOnSurface state = thePropagator->propagate(outerState, theTracker->idToDet(outerDetId)->surface());
    if (!state.isValid()) return ret;
//    TransientTrackingRecHit::RecHitPointer recHit = (theTTRHBuilder->build(hit))->clone(state);
    TransientTrackingRecHit::RecHitPointer recHit =  theTTRHBuilder->build(hit);
    outerState =  updator.update(state, *recHit);
    if (!outerState.isValid()) return ret;
  }
  


  TrajectoryStateOnSurface innerState = outerState;
  DetId innerDetId = 0;
  innerState.rescaleError(100000.);
  for ( int iHit = 2; iHit >= 0; --iHit) {
    hit = hits[iHit];
    innerDetId = hit->geographicalId();
    TrajectoryStateOnSurface state = theOPropagator->propagate(innerState, theTracker->idToDet(innerDetId)->surface());
    if (!state.isValid()) return ret;
//  TransientTrackingRecHit::RecHitPointer recHit = (theTTRHBuilder->build(hit))->clone(state);
    TransientTrackingRecHit::RecHitPointer recHit = theTTRHBuilder->build(hit);
    innerState =  updator.update(state, *recHit);
    if (!innerState.isValid()) return ret;
  }


  // extrapolate to vertex
  TrajectoryStateOnSurface  impactPointState =  TransverseImpactPointExtrapolator(theField).extrapolate( innerState, vertexPos);
  if (!impactPointState.isValid()) return ret;

  //
  // optionally update impact point state with Bs constraint
  // using this potion makes sense if vertexPos (from TrackingRegion is centerewd at BeamSpot).
  //
  if (theBeamSpot) {
    MyBeamSpotGeomDet bsgd(Plane::build(impactPointState.surface().position(), impactPointState.surface().rotation()));
    MyBeamSpotHit     bsrh(*theBeamSpot, &bsgd);
    impactPointState = updator.update(impactPointState, bsrh); //update
    impactPointState = TransverseImpactPointExtrapolator(theField).extrapolate( impactPointState, vertexPos); //reextrapolate
    if (!impactPointState.isValid()) return ret;
  }

  int ndof = 2*hits.size()-5;
  GlobalPoint vv = impactPointState.globalPosition();
  math::XYZPoint  pos( vv.x(), vv.y(), vv.z() );
  GlobalVector pp = impactPointState.globalMomentum();
  math::XYZVector mom( pp.x(), pp.y(), pp.z() );

  float chi2 = 0.;
  ret = std::make_unique<reco::Track>( chi2, ndof, pos, mom,
        impactPointState.charge(), impactPointState.curvilinearError());

/*
    vv = outerState.globalPosition(); 
    pp = outerState.globalMomentum();
    math::XYZPoint  outerPosition( vv.x(), vv.y(), vv.z()); 
    math::XYZVector outerMomentum( pp.x(), pp.y(), pp.z());
    vv = innerState.globalPosition(); 
    pp = innerState.globalMomentum();
    math::XYZPoint  innerPosition( vv.x(), vv.y(), vv.z()); 
    math::XYZVector innerMomentum( pp.x(), pp.y(), pp.z());

    reco::TrackExtra extra( outerPosition, outerMomentum, true,
                      innerPosition, innerMomentum, true,
                      outerState.curvilinearError(), outerDetId,
                      innerState.curvilinearError(), innerDetId,  
                      anyDirection);
*/

//  std::cout <<"TRACK CREATED" << std::endl;
  return ret;
}

Member Data Documentation

const reco::BeamSpot* KFBasedPixelFitter::theBeamSpot

private

Definition at line 67 of file KFBasedPixelFitter.h.

Referenced by run().

const edm::EventSetup* KFBasedPixelFitter::theES

private

Definition at line 61 of file KFBasedPixelFitter.h.

Referenced by run().

const MagneticField* KFBasedPixelFitter::theField

private

Definition at line 66 of file KFBasedPixelFitter.h.

Referenced by run().

const Propagator* KFBasedPixelFitter::theOPropagator

private

Definition at line 63 of file KFBasedPixelFitter.h.

Referenced by run().

const Propagator* KFBasedPixelFitter::thePropagator

private

Definition at line 62 of file KFBasedPixelFitter.h.

Referenced by run().

const TrackerGeometry* KFBasedPixelFitter::theTracker

private

Definition at line 65 of file KFBasedPixelFitter.h.

Referenced by run().

const TransientTrackingRecHitBuilder* KFBasedPixelFitter::theTTRHBuilder

private

Definition at line 64 of file KFBasedPixelFitter.h.

Referenced by run().