class for calculation of chi^2 More...

Public Member Functions
	ChiSquareCalculator ()=default

double	operator() (const double *parameters) const

Public Attributes
const std::map< unsigned int, RPOpticsData > *	m_rp_optics

const CTPPSLocalTrackLiteRefVector *	tracks

Detailed Description

class for calculation of chi^2

Definition at line 72 of file ProtonReconstructionAlgorithm.h.

Constructor & Destructor Documentation

◆ ChiSquareCalculator()

ProtonReconstructionAlgorithm::ChiSquareCalculator::ChiSquareCalculator ( )

default

Member Function Documentation

◆ operator()()

double ProtonReconstructionAlgorithm::ChiSquareCalculator::operator() ( const double * parameters ) const

Definition at line 126 of file ProtonReconstructionAlgorithm.cc.

                                                                                                   {
   // extract proton parameters
   const LHCInterpolatedOpticalFunctionsSet::Kinematics k_in = {
       0., parameters[1], parameters[3], parameters[2], parameters[0]};
  
   // calculate chi^2 by looping over hits
   double s2 = 0.;
  
   for (const auto &track : *tracks) {
     const CTPPSDetId rpId(track->rpId());
  
     // transport proton to the RP
     auto oit = m_rp_optics->find(rpId);
     LHCInterpolatedOpticalFunctionsSet::Kinematics k_out;
     oit->second.optics->transport(k_in, k_out);
  
     // proton position wrt. beam
     const double x = k_out.x - oit->second.x0;
     const double y = k_out.y - oit->second.y0;
  
     // calculate chi^2 contributions, convert track data mm --> cm
     const double x_diff_norm = (x - track->x() * 1E-1) / (track->xUnc() * 1E-1);
     const double y_diff_norm = (y - track->y() * 1E-1) / (track->yUnc() * 1E-1);
  
     // increase chi^2
     s2 += x_diff_norm * x_diff_norm + y_diff_norm * y_diff_norm;
   }
  
   return s2;