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

linearFit()

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 29 of file LinearFit.h.

References ztail::d, diffTwoXMLs::g1, diffTwoXMLs::g2, mps_fire::i, slope, x, and detailsBasic3DVector::y.

Referenced by RZLine::calculate(), and VectorHitBuilderAlgorithm::fit().

                         {
  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;
}