#include <TrackFitter.h>

Inheritance diagram for TrackFitter:

Public Member Functions
virtual reco::Track *	run (const edm::EventSetup &es, const std::vector< const TrackingRecHit * > &hits, const TrackingRegion &region) const

	TrackFitter (const edm::ParameterSet &cfg)

virtual	~TrackFitter ()

Public Member Functions inherited from PixelFitter
virtual reco::Track *	run (const edm::Event &ev, const edm::EventSetup &es, const std::vector< const TrackingRecHit * > &hits, const TrackingRegion &region) const

virtual	~PixelFitter ()

Private Member Functions
int	getCharge (const std::vector< GlobalPoint > &points) const

float	getCotThetaAndUpdateZip (const GlobalPoint &inner, const GlobalPoint &outer, float radius, float phi, float d0, float &zip) const

void	getErrTipAndErrZip (float pt, float eta, float &errZip, float &errTip) const

float	getPhi (float xC, float yC, int charge) const

float	getZip (float d0, float curv, const GlobalPoint &inner, const GlobalPoint &outer) const

Private Attributes
edm::ParameterSet	theConfig

const MagneticField *	theField

const TrackerGeometry *	theTracker

const TransientTrackingRecHitBuilder *	theTTRecHitBuilder

Detailed Description

Definition at line 17 of file TrackFitter.h.

Constructor & Destructor Documentation

TrackFitter::TrackFitter ( const edm::ParameterSet & cfg )

Definition at line 39 of file TrackFitter.cc.

                                :
    theConfig(cfg), theTracker(0), theField(0), theTTRecHitBuilder(0)
 {
 }

virtual TrackFitter::~TrackFitter ( )

inlinevirtual

Definition at line 21 of file TrackFitter.h.

21 { }

Member Function Documentation

int TrackFitter::getCharge ( const std::vector< GlobalPoint > & points ) const

private

Definition at line 140 of file TrackFitter.cc.

References M_PI, and PV3DBase< T, PVType, FrameType >::phi().

 {
    GlobalVector v21 = points[1]-points[0];
    GlobalVector v32 = points[2]-points[1];
    float dphi = v32.phi() - v21.phi();
    while (dphi >  M_PI) dphi -= 2*M_PI;
    while (dphi < -M_PI) dphi += 2*M_PI;
    return (dphi > 0) ? -1 : 1;
 }

float TrackFitter::getCotThetaAndUpdateZip	(	const GlobalPoint &	inner,
		const GlobalPoint &	outer,
		float	radius,
		float	phi,
		float	d0,
		float &	zip
	)		const

private

Definition at line 152 of file TrackFitter.cc.

References funct::cos(), M_PI_2, perp(), funct::sin(), and PV3DBase< T, PVType, FrameType >::z().

 {
    float chi = phi - M_PI_2;
    GlobalPoint IP(d0*cos(chi), d0*sin(chi),zip);
 
    float phi1 = 2*asin(0.5*(inner - IP).perp()/radius);
    float phi2 = 2*asin(0.5*(outer - IP).perp()/radius);
 
    float dr = radius*(phi2 - phi1);
    float dz = outer.z()-inner.z();
 
    // Recalculate ZIP
    zip = (inner.z()*phi2 - outer.z()*phi1)/(phi2 - phi1);
 
    return (fabs(dr) > 1.e-3) ? dz/dr : 0;
 }

void TrackFitter::getErrTipAndErrZip	(	float	pt,
		float	eta,
		float &	errZip,
		float &	errTip
	)		const

private

Definition at line 204 of file TrackFitter.cc.

References mathSSE::sqrt().

 {
   float coshEta = cosh(eta);
 
   { // transverse
     float c_ms = 0.0115; //0.0115;
     float s_le = 0.0095; //0.0123;
     float s_ms2 = c_ms*c_ms / (pt*pt) * coshEta;
 
     errTip = sqrt(s_le*s_le + s_ms2                  );
   }
 
   { // z
     float c_ms = 0.0070;
     float s_le = 0.0135;
 
     errZip = sqrt( (s_le*s_le + c_ms*c_ms/(pt*pt)) * coshEta*coshEta*coshEta);
   }
 }

float TrackFitter::getPhi	(	float	xC,
		float	yC,
		int	charge
	)		const

private

Definition at line 172 of file TrackFitter.cc.

 {
   float phiC;
 
   if (charge>0) phiC = atan2(xC,-yC);
            else phiC = atan2(-xC,yC);
 
   return phiC;
 }

float TrackFitter::getZip	(	float	d0,
		float	curv,
		const GlobalPoint &	inner,
		const GlobalPoint &	outer
	)		const

private

Definition at line 184 of file TrackFitter.cc.

References PV3DBase< T, PVType, FrameType >::perp(), PV3DBase< T, PVType, FrameType >::perp2(), diffTwoXMLs::r1, diffTwoXMLs::r2, and PV3DBase< T, PVType, FrameType >::z().

 {
   // phi = asin(r*rho/2) with asin(x) ~= x+x**3/(2*3)
   float rho3 = curv*curv*curv;
 
   float r1 = inner.perp();
   double phi1 = r1*curv/2 + inner.perp2()*r1*rho3/48.;
 
   float r2 = outer.perp();
   double phi2 = r2*curv/2 + outer.perp2()*r2*rho3/48.;
 
   double z1 = inner.z();
   double z2 = outer.z();
 
   return z1 - phi1/(phi1-phi2)*(z1-z2);
 }

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

virtual

Reimplemented from PixelFitter.

Definition at line 46 of file TrackFitter.cc.

References PixelTrackBuilder::build(), CircleFromThreePoints::center(), DeDxDiscriminatorTools::charge(), RZLine::chi2(), PixelRecoUtilities::curvature(), CircleFromThreePoints::curvature(), benchmark_cfg::errors, RZLine::fit(), edm::EventSetup::get(), PixelRecoUtilities::inversePt(), Basic2DVector< T >::mag(), phi, edm::ESHandle< class >::product(), Basic2DVector< T >::x(), and Basic2DVector< T >::y().

 {
   int nhits = hits.size();
   if(nhits <2) return 0;
 
   vector<GlobalPoint> points;
   vector<GlobalError> errors;
   vector<bool> isBarrel;
   
   if (!theField || !theTracker || !theTTRecHitBuilder)
   {
     edm::ESHandle<TrackerGeometry> trackerESH;
     es.get<TrackerDigiGeometryRecord>().get(trackerESH);
     theTracker = trackerESH.product();
 
     edm::ESHandle<MagneticField> fieldESH;
     es.get<IdealMagneticFieldRecord>().get(fieldESH);
     theField = fieldESH.product();
 
     edm::ESHandle<TransientTrackingRecHitBuilder> ttrhbESH;
     std::string builderName = theConfig.getParameter<std::string>("TTRHBuilder");
     es.get<TransientRecHitRecord>().get(builderName,ttrhbESH);
     theTTRecHitBuilder = ttrhbESH.product();
   }
 
   for (vector<const TrackingRecHit*>::const_iterator ih = hits.begin();
                                                      ih!= hits.end(); ih++)
   {
     TransientTrackingRecHit::RecHitPointer recHit =
       theTTRecHitBuilder->build(*ih);
 
     points.push_back(recHit->globalPosition());
     errors.push_back(recHit->globalPositionError());
     isBarrel.push_back(recHit->detUnit()->type().isBarrel() );
   }
 
   CircleFromThreePoints circle = (nhits==2) ?
         CircleFromThreePoints(GlobalPoint(0.,0.,0.), points[0], points[1]) :
         CircleFromThreePoints(points[0],points[1],points[2]); 
 
   int charge = getCharge(points);
   float curvature = circle.curvature();
 
   // pt
   float invPt = PixelRecoUtilities::inversePt(curvature, es);
   float valPt = (invPt > 1.e-4) ? 1./invPt : 1.e4;
   float errPt = 0.055*valPt + 0.017*valPt*valPt;
 
   CircleFromThreePoints::Vector2D center = circle.center();
 
   // tip
   float valTip = charge * (center.mag()-1/curvature);
   // zip
   float valZip = getZip(valTip, curvature, points[0],points[1]);
   // phi
   float valPhi = getPhi(center.x(), center.y(), charge);
   // cot(theta), update zip
   float valCotTheta =
      getCotThetaAndUpdateZip(points[0],points[1], 1/curvature,
                              valPhi,valTip,valZip);
 
   // errors
   float errTip, errZip;
   getErrTipAndErrZip(valPt, points.back().eta(), errTip,errZip);
   float errPhi      = 0.002;
   float errCotTheta = 0.002;
 
   float chi2 = 0;
   if(nhits > 2)
   {
     RZLine rzLine(points,errors,isBarrel);
     float      cotTheta, intercept, covss, covii, covsi; 
     rzLine.fit(cotTheta, intercept, covss, covii, covsi);
     chi2 = rzLine.chi2(cotTheta, intercept);
     //FIXME: check which intercept to use!
   }
 
   // build pixel track
   PixelTrackBuilder builder;
 
   Measurement1D pt      (valPt,       errPt);
   Measurement1D phi     (valPhi,      errPhi);
   Measurement1D cotTheta(valCotTheta, errCotTheta);
   Measurement1D tip     (valTip,      errTip);
   Measurement1D zip     (valZip,      errZip);
 
   return builder.build(pt, phi, cotTheta, tip, zip, chi2,
                        charge, hits, theField);
 }

Member Data Documentation

edm::ParameterSet TrackFitter::theConfig

private

Definition at line 38 of file TrackFitter.h.

const MagneticField* TrackFitter::theField

mutableprivate

Definition at line 41 of file TrackFitter.h.

const TrackerGeometry* TrackFitter::theTracker

mutableprivate

Definition at line 40 of file TrackFitter.h.

const TransientTrackingRecHitBuilder* TrackFitter::theTTRecHitBuilder

mutableprivate

Definition at line 42 of file TrackFitter.h.

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation