#include <PixelFitterByConformalMappingAndLine.h>

Inheritance diagram for PixelFitterByConformalMappingAndLine:

Public Member Functions
	PixelFitterByConformalMappingAndLine (const TransientTrackingRecHitBuilder ttrhBuilder, const TrackerGeometry tracker, const MagneticField *field, double fixImpactParameter, bool useFixImpactParameter)

std::unique_ptr< reco::Track >	run (const std::vector< const TrackingRecHit * > &hits, const TrackingRegion &region, const edm::EventSetup &setup) const override

	~PixelFitterByConformalMappingAndLine () override

Public Member Functions inherited from PixelFitterBase
virtual	~PixelFitterBase ()

Private Attributes
const MagneticField *	theField

const double	theFixImpactParameter

const TrackerGeometry *	theTracker

const TransientTrackingRecHitBuilder *	theTTRHBuilder

const bool	theUseFixImpactParameter

Detailed Description

Definition at line 14 of file PixelFitterByConformalMappingAndLine.h.

Constructor & Destructor Documentation

◆ PixelFitterByConformalMappingAndLine()

PixelFitterByConformalMappingAndLine::PixelFitterByConformalMappingAndLine	(	const TransientTrackingRecHitBuilder *	ttrhBuilder,
		const TrackerGeometry *	tracker,
		const MagneticField *	field,
		double	fixImpactParameter,
		bool	useFixImpactParameter
	)

explicit

Definition at line 35 of file PixelFitterByConformalMappingAndLine.cc.

     : theTTRHBuilder(ttrhBuilder),
       theTracker(tracker),
       theField(field),
       theFixImpactParameter(fixImpactParameter),
       theUseFixImpactParameter(useFixImpactParameter) {}

◆ ~PixelFitterByConformalMappingAndLine()

PixelFitterByConformalMappingAndLine::~PixelFitterByConformalMappingAndLine ( )

inlineoverride

Definition at line 21 of file PixelFitterByConformalMappingAndLine.h.

21 {}

Member Function Documentation

◆ run()

std::unique_ptr< reco::Track > PixelFitterByConformalMappingAndLine::run	(	const std::vector< const TrackingRecHit * > &	hits,
		const TrackingRegion &	region,
		const edm::EventSetup &	setup
	)		const

overridevirtual

Implements PixelFitterBase.

Definition at line 47 of file PixelFitterByConformalMappingAndLine.cc.

                                                                                                          {
   int nhits = hits.size();
  
   vector<GlobalPoint> points;
   vector<GlobalError> errors;
   vector<bool> isBarrel;
  
   for (vector<const TrackingRecHit *>::const_iterator ih = hits.begin(); ih != hits.end(); ih++) {
     TransientTrackingRecHit::RecHitPointer recHit = theTTRHBuilder->build(*ih);
     points.push_back(recHit->globalPosition());
     errors.push_back(recHit->globalPositionError());
     isBarrel.push_back(recHit->detUnit()->type().isBarrel());
   }
  
   //    if (useMultScatt) {
   //      MultipleScatteringParametrisation ms(hits[i].layer());
   //      float cotTheta = (p.z()-zVtx)/p.perp();
   //      err += sqr( ms( pt, cotTheta, PixelRecoPointRZ(0.,zVtx) ) );
   //    }
  
   //
   // simple fit to get pt, phi0 used for precise calcul.
   //
   typedef ConformalMappingFit::PointXY PointXY;
   vector<PointXY> xy;
   vector<float> errRPhi2;
   for (int i = 0; i < nhits; ++i) {
     const GlobalPoint &point = points[i];
     xy.push_back(PointXY(point.x() - region.origin().x(), point.y() - region.origin().y()));
     float phiErr2 = errors[i].phierr(point);
     errRPhi2.push_back(point.perp2() * phiErr2);
   }
   ConformalMappingFit parabola(xy, errRPhi2);
   if (theUseFixImpactParameter)
     parabola.fixImpactParmaeter(theFixImpactParameter);
   else if (nhits < 3)
     parabola.fixImpactParmaeter(0.);
  
   Measurement1D curv = parabola.curvature();
   float invPt = PixelRecoUtilities::inversePt(curv.value(), setup);
   float valPt = (invPt > 1.e-4) ? 1. / invPt : 1.e4;
   float errPt = PixelRecoUtilities::inversePt(curv.error(), setup) * sqr(valPt);
   Measurement1D pt(valPt, errPt);
   Measurement1D phi = parabola.directionPhi();
   Measurement1D tip = parabola.impactParameter();
  
   //
   // precalculate theta to correct errors:
   //
   vector<float> r(nhits), z(nhits), errZ(nhits);
   float simpleCot = (points.back().z() - points.front().z()) / (points.back().perp() - points.front().perp());
   for (int i = 0; i < nhits; ++i) {
     const GlobalPoint &point = points[i];
     const GlobalError &error = errors[i];
     r[i] = sqrt(sqr(point.x() - region.origin().x()) + sqr(point.y() - region.origin().y()));
     r[i] += pixelrecoutilities::LongitudinalBendingCorrection(pt.value(), setup)(r[i]);
     z[i] = point.z() - region.origin().z();
     errZ[i] = (isBarrel[i]) ? sqrt(error.czz()) : sqrt(error.rerr(point)) * simpleCot;
   }
  
   //
   // line fit (R-Z plane)
   //
   RZLine rzLine(r, z, errZ);
  
   //
   // parameters for track builder
   //
   Measurement1D zip(rzLine.intercept(), sqrt(rzLine.covii()));
   Measurement1D cotTheta(rzLine.cotTheta(), sqrt(rzLine.covss()));
   float chi2 = parabola.chi2() + rzLine.chi2();
   int charge = parabola.charge();
  
   PixelTrackBuilder builder;
   return std::unique_ptr<reco::Track>(
       builder.build(pt, phi, cotTheta, tip, zip, chi2, charge, hits, theField, region.origin()));
 }