Fitter Class Reference

#include <fitter.h>

Public Member Functions
void	addPoint (double x, double y)
bool	evaluateLinearFit ()
	Fitter ()
double	getChi2 ()
double	getIntercept ()
double	getPearsonCoefficent ()
double	getSlope ()
void	printStatistics ()
void	setErrXY (double errx, double erry)
	~Fitter ()

Private Attributes
double	_chi2
double	_errx
double	_erry
double	_m
unsigned short	_nPoints
double	_q
double	_r
std::vector< double >	_x
std::vector< double >	_y

Constructor & Destructor Documentation

Fitter()

Fitter::Fitter

(

)

{
    _x.clear();
    _y.clear();
    _errx = _erry = _chi2 = _m = _q = _r = 0;
    _nPoints = 0;
}

~Fitter()

Fitter::~Fitter

(

)

{
}

Member Function Documentation

addPoint()

void Fitter::addPoint	(	double	x,
		double	y
	)

{
    _x.push_back(x);
    _y.push_back(y);
    _nPoints++;
}

evaluateLinearFit()

bool Fitter::evaluateLinearFit

(

)

{
    if (_nPoints == 0 || _erry == 0)
        return false;
    double s = 0, sx = 0, sy = 0, sxx = 0, syy = 0, sxy = 0;
    double d = _errx / _erry;
    //unsigned int nPoints = static_cast<unsigned int>(_x.size());
    for (unsigned short i = 0; i < _nPoints; i++)
    {
        double x = _x.at(i);
        double y = _y.at(i);
        s   += 1;       
        sx  += x;
        sy  += y;
        sxx += x*x;
        syy += y*y;
        sxy += x*y;
    }
 
    _r  = (s*sxy-sx*sy)/(sqrt(s*sxx-sx*sx)*sqrt(s*syy-sy*sy));
    s/=_errx;
    sx/=_errx;
    sy/=_errx;
    sxx/=_errx;
    syy/=_errx;
    sxy/=_errx;
    
    double den  = 1./(s*sxx - sx*sx);
    _m = (s*sxy - sx*sy)*den;
    //_r  = (s*sxy-sx*sy)/(sqrt(s*sxx-sx*sx)*sqrt(s*syy-sy*sy));
    double r2 = _r*_r;
    _m = 1./(2*d)*(-1./(d*_m)+d*_m/r2+1./(d*_m)*sqrt((1-d*d*_m*_m/r2)*(1-d*d*_m*_m/r2)+4*d*d*_m*_m));
    _q = (sy-sx*_m)/s;
    
    for (unsigned short i = 0; i < _nPoints; i++)
    {
        double x = _x.at(i);
        double y = _y.at(i);
        _chi2 += ((y-_q-_m*x)*(y-_q-_m*x))/((_erry*_erry)+_m*(_errx*_errx));
    }
 
    //_chi2/=(1+d*d*_m*_m);
                
    return true;
}

getChi2()

double Fitter::getChi2 ( )

inline

{return _chi2;};

getIntercept()

double Fitter::getIntercept ( )

inline

{return _q;};

getPearsonCoefficent()

double Fitter::getPearsonCoefficent ( )

inline

{return _r;};

getSlope()

double Fitter::getSlope ( )

inline

{return _m;};

printStatistics()

void Fitter::printStatistics

(

)

{
    std::cout << "nPoints: " << _nPoints
        << "\n y = " << _m << " * x + " << _q 
        << "\n r = " << _r << "\nchi2 = " << _chi2 << std::endl;
}

setErrXY()

void Fitter::setErrXY	(	double	errx,
		double	erry
	)

{
    _errx = errx;
    _erry = erry;
}

Member Data Documentation

_chi2

double Fitter::_chi2

private

_errx

double Fitter::_errx

private

_erry

double Fitter::_erry

private

_m

double Fitter::_m

private

_nPoints

unsigned short Fitter::_nPoints

private

_q

double Fitter::_q

private

_r

double Fitter::_r

private

_x

std::vector<double> Fitter::_x

private

_y

std::vector<double> Fitter::_y

private

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The documentation for this class was generated from the following files:

• src/appl/rwcToEdb/fitter.h
• src/appl/rwcToEdb/fitter.cpp