TrackFitter Class Reference

#include <TrackFitter.h>

Inheritance diagram for TrackFitter:

Public Member Functions
std::unique_ptr< reco::Track >	run (const std::vector< const TrackingRecHit * > &hits, const TrackingRegion &region, const edm::EventSetup &setup) const override
	TrackFitter (const TrackerGeometry *tracker, const MagneticField *field, const TransientTrackingRecHitBuilder *ttrhBuilder)
	~TrackFitter () override
Public Member Functions inherited from PixelFitterBase
virtual	~PixelFitterBase ()

Private Member Functions
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
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 TrackerGeometry *  tracker, const MagneticField *  field, const TransientTrackingRecHitBuilder *  ttrhBuilder  )

inline

Definition at line 20 of file TrackFitter.h.

                                                                                            :
    theTracker(tracker), theField(field), theTTRecHitBuilder(ttrhBuilder)
  {}

TrackFitter::~TrackFitter ( )

inlineoverride

Definition at line 24 of file TrackFitter.h.

References ALCARECOTkAlJpsiMuMu_cff::charge, allConversions_cfi::d0, PVValHelper::eta, getCotThetaAndUpdateZip(), getErrTipAndErrZip(), getPhi(), getZip(), hfClusterShapes_cfi::hits, SurfaceOrientation::inner, SurfaceOrientation::outer, phi, EnergyCorrector::pt, TCMET_cfi::radius, run(), GeneralSetup::setup(), and ComparisonHelper::zip().

{ }

Member Function Documentation

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

private

Definition at line 121 of file TrackFitter.cc.

References funct::cos(), runTauDisplay::dr, PVValHelper::dz, getPhi(), listHistos::IP, M_PI_2, perp(), funct::sin(), and PV3DBase< T, PVType, FrameType >::z().

Referenced by run(), and ~TrackFitter().

{
   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 173 of file TrackFitter.cc.

References EnergyCorrector::pt, and mathSSE::sqrt().

Referenced by getZip(), and ~TrackFitter().

{
  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 141 of file TrackFitter.cc.

References getZip().

Referenced by getCotThetaAndUpdateZip(), and ~TrackFitter().

{
  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 153 of file TrackFitter.cc.

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

Referenced by getPhi(), and ~TrackFitter().

{
  // 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);
}

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

overridevirtual

Implements PixelFitterBase.

Definition at line 43 of file TrackFitter.cc.

References PixelTrackBuilder::build(), CircleFromThreePoints::center(), ALCARECOTkAlJpsiMuMu_cff::charge, vertices_cff::chi2, RZLine::chi2(), PixelRecoUtilities::curvature(), CircleFromThreePoints::curvature(), declareDynArray, vertexPlots::e4, DeDxTools::getCharge(), getCotThetaAndUpdateZip(), mps_fire::i, PixelRecoUtilities::inversePt(), GeomDetEnumerators::isBarrel(), Basic2DVector< T >::mag(), nhits, EnergyCorrector::pt, rpcPointValidation_cfi::recHit, btvTracks_cfi::tip, Basic2DVector< T >::x(), Basic2DVector< T >::y(), and ComparisonHelper::zip().

Referenced by ~TrackFitter().

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

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

  declareDynArray(GlobalPoint,nhits, points);
  declareDynArray(GlobalError,nhits, errors);
  declareDynArray(bool,nhits, isBarrel);
  
  unsigned int i=0;
  for (auto const & ih  : hits)
  {
    auto recHit = theTTRecHitBuilder->build(ih);

    points[i] = recHit->globalPosition();
    errors[i] = recHit->globalPositionError();
    isBarrel[++i] = 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, setup);
  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);
    chi2 = rzLine.chi2();
  }

  // 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);

  ret.reset(builder.build(pt, phi, cotTheta, tip, zip, chi2,
                          charge, hits, theField));
  return ret;
}

Member Data Documentation

const MagneticField* TrackFitter::theField

private

Definition at line 39 of file TrackFitter.h.

const TrackerGeometry* TrackFitter::theTracker

private

Definition at line 38 of file TrackFitter.h.

const TransientTrackingRecHitBuilder* TrackFitter::theTTRecHitBuilder

private

Definition at line 40 of file TrackFitter.h.