CMSSW Reference Manual

List of all members.


Public Member Functions
void	fit (const std::vector< float > &x, const std::vector< float > &y, int ndat, const std::vector< float > &sigy, float &slope, float &intercept, float &covss, float &covii, float &covsi) const
	x_i, y_i: measurements of y(x_i), sigy_i: error (sigma) on y_i slope, intercept: fitted parameters covss, covii, covsi: covariance matrix of fitted parameters, s denoting slope, i denoting intercept

void LinearFit::fit	(	const std::vector< float > &	x,
		const std::vector< float > &	y,
		int	ndat,
		const std::vector< float > &	sigy,
		float &	slope,
		float &	intercept,
		float &	covss,
		float &	covii,
		float &	covsi
	)			const

x_i, y_i: measurements of y(x_i), sigy_i: error (sigma) on y_i slope, intercept: fitted parameters covss, covii, covsi: covariance matrix of fitted parameters, s denoting slope, i denoting intercept

Definition at line 3 of file LinearFit.cc.

References d, g1, g2, i, s12, and s22.

Referenced by LinearFitErrorsIn2Coord::slope().

00007 {
00008 
00009   float g1 = 0, g2 = 0;
00010   float s11 = 0, s12 = 0, s22 = 0;
00011   for (int i = 0; i != ndat; i++) {
00012     float sy2 = sigy[i] * sigy[i];
00013     g1 += y[i] / sy2;
00014     g2 += x[i]*y[i] / sy2;
00015     s11 += 1. / sy2;
00016     s12 += x[i] / sy2;
00017     s22 += x[i]*x[i] / sy2;
00018   }
00019 
00020   float d = s11*s22 - s12*s12;
00021   intercept = (g1*s22 - g2*s12) / d;
00022   slope = (g2*s11 - g1*s12) / d;
00023 
00024   covii =  s22 / d;
00025   covss =  s11 / d;
00026   covsi = -s12 / d;
00027   
00028 }

LinearFit Class Reference

Public Member Functions

Detailed Description

Member Function Documentation