/afs/cern.ch/work/a/aaltunda/public/www/CMSSW_6_2_5/src/RecoPixelVertexing/PixelTrackFitting/src/ConformalMappingFit.cc

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#include "ConformalMappingFit.h"

using namespace std;

template <class T> T sqr( T t) {return t*t;}

ConformalMappingFit::ConformalMappingFit(
  const std::vector<PointXY> & hits, const std::vector<float> & errRPhi2, const Rotation * rot)
  : theRotation(rot), myRotation(rot==0)
{
  typedef ConformalMappingFit::MappedPoint<double> PointUV;
  int hits_size = hits.size();
  for ( int i= 0; i < hits_size; i++) {
    if (!theRotation) findRot( hits[i] );
    PointUV point( hits[i], 1./errRPhi2[i], theRotation); 
    theFit.addPoint( point.u(), point.v(), point.weight());
  }
}

void ConformalMappingFit::findRot(const PointXY & p) 
{
  myRotation = true;
  typedef  Rotation::GlobalVector GlobalVector; // ::GlobalVector is float!
  GlobalVector aX = GlobalVector( p.x(), p.y(), 0.).unit();
  GlobalVector aY( -aX.y(), aX.x(), 0.);
  GlobalVector aZ( 0., 0., 1.);
  theRotation = new Rotation(aX,aY,aZ);
}

ConformalMappingFit::~ConformalMappingFit()
{ if( myRotation) delete theRotation; }

double ConformalMappingFit::phiRot() const
{ return atan2( theRotation->xy(), theRotation->xx() ); }

Measurement1D ConformalMappingFit::curvature() const
{
  double val = fabs( 2. * theFit.parA() );
  double err  = 2.*sqrt(theFit.varAA());
  return Measurement1D(val,err);
}

Measurement1D ConformalMappingFit::directionPhi() const
{
  double val = phiRot() + atan(theFit.parB());
  double err = sqrt(theFit.varBB());
  return Measurement1D(val,err);
}

Measurement1D ConformalMappingFit::impactParameter() const
{
  double val = -theFit.parC(); 
  double err = sqrt(theFit.varCC());
  return Measurement1D(val,err);
}

int ConformalMappingFit::charge() const
{ return (theFit.parA() > 0.) ? -1 : 1; }