/data/refman/pasoursint/CMSSW_5_3_3/src/CommonTools/Statistics/interface/LinearFit.h File Reference

#include <vector>

Go to the source code of this file.

Classes
class	LinearFit
Functions
template<typename T >
void	linearFit (T const *__restrict__ x, T const *__restrict__ y, int ndat, T const *__restrict__ sigy2, T &slope, T &intercept, T &covss, T &covii, T &covsi)

---

Function Documentation

template<typename T >

void linearFit	(	T const *__restrict__	x,
		T const *__restrict__	y,
		int	ndat,
		T const *__restrict__	sigy2,
		T &	slope,
		T &	intercept,
		T &	covss,
		T &	covii,
		T &	covsi
	)

Definition at line 26 of file LinearFit.h.

References diffTwoXMLs::g1, diffTwoXMLs::g2, and i.

Referenced by RZLine::fit(), RoadSearchTrackCandidateMakerAlgorithm::initialTrajectory(), and RoadSearchTrackCandidateMakerAlgorithm::initialTrajectoryFromTriplet().

                                                 {
  T g1 = 0, g2 = 0;
  T s11 = 0, s12 = 0, s22 = 0;
  for (int i = 0; i != ndat; i++) {
    T sy2 = T(1)/sigy2[i];
    g1 += y[i] *sy2;
    g2 += x[i]*y[i] * sy2;
    s11 += sy2;
    s12 += x[i] * sy2;
    s22 += x[i]*x[i] * sy2;
  }
  
  T d = T(1)/(s11*s22 - s12*s12);
  intercept = (g1*s22 - g2*s12) * d;
  slope = (g2*s11 - g1*s12) * d;
  
  covii =  s22 * d;
  covss =  s11 * d;
  covsi = -s12 * d;
}