lsst::meas::astrom::sip::LeastSqFitter1d< FittingFunc > Class Template Reference

Fit an lsst::afw::math::Function1 object to a set of data points in one dimension. More...

#include <LeastSqFitter1d.h>

Public Member Functions
	LeastSqFitter1d (const std::vector< double > &x, const std::vector< double > &y, const std::vector< double > &s, int order)
	Fit a 1d polynomial to a set of data points z(x, y) More...
Eigen::VectorXd	getParams ()
	Return the best fit parameters as an Eigen::Matrix. More...
Eigen::VectorXd	getErrors ()
	Return the 1 sigma uncertainties in the best fit parameters as an Eigen::Matrix. More...
FittingFunc	getBestFitFunction ()
	Return the best fit polynomial as a lsst::afw::math::Function1 object. More...
double	valueAt (double x)
	Calculate the value of the function at a given point. More...
std::vector< double >	residuals ()
	Return a vector of residuals of the fit (i.e the difference between the input y values, and the value of the fitting function at that point. More...
double	getChiSq ()
	Return a measure of the goodness of fit. More...
double	getReducedChiSq ()
	Return a measure of the goodness of fit. More...

Detailed Description

template<class FittingFunc>
class lsst::meas::astrom::sip::LeastSqFitter1d< FittingFunc >

Fit an lsst::afw::math::Function1 object to a set of data points in one dimension.

The class is templated over the kind of object to fit.

Input is a list of x ordinates for a set of points, the y coordinate, and the uncertainties, s. order is order of the polynomial to fit (e.g if the templated function is lsst::afw::math::PolynomialFunction1, then order=3 => fit a function of the form \(ax^2+bx+c\)

Template Parameters

FittingFunc

The 1d function to fit in both dimensions. Must inherit from lsst::afw::math::Function1

Parameters

x	Ordinate of points to fit
y	Co-ordinate of pionts to fit
s	1 \(\sigma\) uncertainties in z
order	Polynomial order to fit

See also

LeastSqFitter1d

Definition at line 64 of file LeastSqFitter1d.h.

Constructor & Destructor Documentation

LeastSqFitter1d()

template<class FittingFunc >

lsst::meas::astrom::sip::LeastSqFitter1d< FittingFunc >::LeastSqFitter1d	(	const std::vector< double > &	x,
		const std::vector< double > &	y,
		const std::vector< double > &	s,
		int	order
	)

Fit a 1d polynomial to a set of data points z(x, y)

Template Parameters

FittingFunc

The type of function to fit. This function extends the base class of lsst::afw::math::Function1

Parameters

x	vector of x positions of data
y	vector of y positions of data
s	Vector of measured uncertainties in the values of z
order	Order of 2d function to fit

Definition at line 104 of file LeastSqFitter1d.h.

Member Function Documentation

getBestFitFunction()

template<class FittingFunc >

FittingFunc lsst::meas::astrom::sip::LeastSqFitter1d< FittingFunc >::getBestFitFunction

(

)

Return the best fit polynomial as a lsst::afw::math::Function1 object.

Definition at line 160 of file LeastSqFitter1d.h.

getChiSq()

template<class FittingFunc >

double lsst::meas::astrom::sip::LeastSqFitter1d< FittingFunc >::getChiSq

(

)

Return a measure of the goodness of fit.

\[ \chi_r^2 = \sum \left( \frac{y_i - f(x_i)}{s} \right)^2 \]

Definition at line 199 of file LeastSqFitter1d.h.

getErrors()

template<class FittingFunc >

Eigen::VectorXd lsst::meas::astrom::sip::LeastSqFitter1d< FittingFunc >::getErrors

(

)

Return the 1 sigma uncertainties in the best fit parameters as an Eigen::Matrix.

Definition at line 149 of file LeastSqFitter1d.h.

getParams()

template<class FittingFunc >

Eigen::VectorXd lsst::meas::astrom::sip::LeastSqFitter1d< FittingFunc >::getParams

(

)

Return the best fit parameters as an Eigen::Matrix.

Definition at line 139 of file LeastSqFitter1d.h.

getReducedChiSq()

template<class FittingFunc >

double lsst::meas::astrom::sip::LeastSqFitter1d< FittingFunc >::getReducedChiSq

(

)

Return a measure of the goodness of fit.

\[ \chi_r^2 = \sum \left( \frac{y_i - f(x_i)}{s} \right)^2 \div (N-p) \]

Where \( N \) is the number of data points, and \( p \) is the number of parameters in the fit

Definition at line 218 of file LeastSqFitter1d.h.

residuals()

template<class FittingFunc >

std::vector< double > lsst::meas::astrom::sip::LeastSqFitter1d< FittingFunc >::residuals

(

)

Return a vector of residuals of the fit (i.e the difference between the input y values, and the value of the fitting function at that point.

Definition at line 182 of file LeastSqFitter1d.h.

valueAt()

template<class FittingFunc >

double lsst::meas::astrom::sip::LeastSqFitter1d< FittingFunc >::valueAt

(

double

x

)

Calculate the value of the function at a given point.

Definition at line 173 of file LeastSqFitter1d.h.

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

• include/lsst/meas/astrom/sip/LeastSqFitter1d.h