fit the parameters of a \(\chi^2\) shape function. More...

#include "NAGASH/Chi2Fitter.h"

Inheritance diagram for NAGASH::Chi2Fitter:

Classes
class	Chi2FitterFCN
	fcn function to calculate the \(\chi^2\) More...

Public Types
enum class	FitMethod { Eigen , Minuit }
	Fit method. More...

Public Member Functions
	Chi2Fitter (std::shared_ptr< MSGTool >, uint64_t)
	Constructor.

	Chi2Fitter (std::shared_ptr< MSGTool >, uint64_t, TH1D , TH2D _cov_=nullptr)
	Constructor.

const TMatrixD &	Cov ()

double	Error (uint64_t)
	Get the fit error of ith parameter.

void	Fit (FitMethod fm=FitMethod::Eigen)
	Start to fit.

double	FitChi2 ()
	Get the \(\chi^2\) of the fitting procedure.

double	GetChi2 (uint64_t)
	Get the \(\chi^2\) of ith model.

double	OffSet ()
	The offset parameter \( b\) of the fitted \(\chi^2\) function.

void	SetModel (const std::vector< double > &, double)
	Set the \(\chi^2\) value of a set of parameters.

void	SetModel (const std::vector< double > &, TH1D , TH2D cov=nullptr)
	Set the model with a set of parameter.

void	SetRange (int min, int max)
	Set the range of calculation of \(\chi^2\) of the target histogram.

const std::vector< double > &	Value ()

double	Value (uint64_t)
	Get the best-fit value of ith parameter.

Private Attributes
double	chi2 = 0

TMatrixD	cov

uint64_t	dimension = 1

HistTool	histtool

bool	isvalid = false

double	offset = 0

int	RangeMax = 1

int	RangeMin = 1

TH1D *	target = nullptr

TH2D *	targetcov = nullptr

std::vector< double >	value

std::vector< double >	vchi2

std::vector< std::vector< double > >	vvalue

std::vector< double >	vvaluemax

std::vector< double >	vvaluemin

Additional Inherited Members
Protected Member Functions inherited from NAGASH::Tool
	Tool ()=delete

	Tool (const Tool &tool)=delete

	Tool (std::shared_ptr< MSGTool > MSG)
	Constructor.

	Tool (Tool &&tool)=delete

virtual	~Tool ()=default

std::shared_ptr< MSGTool >	MSGUser ()
	return the MSGTool inside.

Tool &	operator= (const Tool &tool)=delete

Tool &	operator= (Tool &&tool)=delete

Detailed Description

fit the parameters of a \(\chi^2\) shape function.

For a given set of \(\chi^2\) at different points: \((\vec{x},\chi^2)\), fit to the quadratic function:

\[ \chi^2(\vec{x},\vec{v},\Sigma)=(\vec{x}-\vec{v})^{T}\Sigma^{-1}(\vec{x}-\vec{v})+b \]

Where \(\vec{v}\) are best-fit value of parameters with \(\Sigma\) as their covariance matrix.

This tool provides methods of processing histograms. Firstly, user should pass the target histogram as well as its covariance matrix to this tool, then set different models with different parameters. Then the \(\chi^2\)s are calculated and best-fit parameters are fitted along with their covariance matrix.

Definition at line 23 of file Chi2Fitter.h.

Member Enumeration Documentation

◆ FitMethod

enum class NAGASH::Chi2Fitter::FitMethod

strong

Fit method.

Enumerator
Eigen	use matrix calculation to get the fitted value, Eigen library is used.
Minuit	use minuit library to fit the value.

Definition at line 27 of file Chi2Fitter.h.

Constructor & Destructor Documentation

◆ Chi2Fitter() [1/2]

Chi2Fitter::Chi2Fitter	(	std::shared_ptr< MSGTool >	msg,
		uint64_t	dim,
		TH1D *	_target_,
		TH2D *	_cov_ = `nullptr`
	)

Constructor.

Parameters

msg	input MSGTool.
dim	the degrees of freedomof the \(\chi^2\).
_target_	the target histogram to be compared with.
_cov_	the covariance matrix of the target histogram.

Definition at line 32 of file Chi2Fitter.cxx.

◆ Chi2Fitter() [2/2]

Chi2Fitter::Chi2Fitter	(	std::shared_ptr< MSGTool >	msg,
		uint64_t	dim
	)

Constructor.

Parameters

msg	input MSGTool.
dim	the degrees of freedomof the \(\chi^2\).

Definition at line 51 of file Chi2Fitter.cxx.

Member Function Documentation

◆ Cov()

const TMatrixD & NAGASH::Chi2Fitter::Cov ( )

inline

Definition at line 44 of file Chi2Fitter.h.

◆ Error()

double Chi2Fitter::Error ( uint64_t index )

Get the fit error of ith parameter.

Parameters

index index of the parameter.

Returns: error of ith parameter.

Definition at line 242 of file Chi2Fitter.cxx.

◆ Fit()

void Chi2Fitter::Fit ( FitMethod fm = FitMethod::Eigen )

Start to fit.

Parameters

fm	the fit method.

Definition at line 315 of file Chi2Fitter.cxx.

◆ FitChi2()

double Chi2Fitter::FitChi2 ( )

Get the \(\chi^2\) of the fitting procedure.

Returns: the \(\chi^2\) of the fitting procedure.

Definition at line 223 of file Chi2Fitter.cxx.

◆ GetChi2()

double Chi2Fitter::GetChi2 ( uint64_t index )

Get the \(\chi^2\) of ith model.

Parameters

index the index of the model.

Returns: the \(\chi^2\) value.

Definition at line 213 of file Chi2Fitter.cxx.

◆ OffSet()

double Chi2Fitter::OffSet ( )

The offset parameter \( b\) of the fitted \(\chi^2\) function.

Returns: the offset parameter \( b\).

Definition at line 252 of file Chi2Fitter.cxx.

◆ SetModel() [1/2]

void Chi2Fitter::SetModel	(	const std::vector< double > &	vv,
		double	_chi2_
	)

Set the \(\chi^2\) value of a set of parameters.

Parameters

vv	the set of parameters, must be the same size as the dimension of the \(\chi^2\).
_chi2_	the corresponding \(\chi^2\) value.

Definition at line 77 of file Chi2Fitter.cxx.

◆ SetModel() [2/2]

void Chi2Fitter::SetModel	(	const std::vector< double > &	vv,
		TH1D *	hmodel,
		TH2D *	covmodel = `nullptr`
	)

Set the model with a set of parameter.

Parameters

vv	the parameters defining the model, must be the same size as the dimension of the \(\chi^2\).
hmodel	the histogram of the model.
covmodel	the covariance matrix of the histogram.

Definition at line 111 of file Chi2Fitter.cxx.

◆ SetRange()

void Chi2Fitter::SetRange	(	int	min,
		int	max
	)

Set the range of calculation of \(\chi^2\) of the target histogram.

Parameters

min	mininum bin index.
max	maximum bin index.

Definition at line 60 of file Chi2Fitter.cxx.

◆ Value() [1/2]

const std::vector< double > & NAGASH::Chi2Fitter::Value ( )

inline

Definition at line 43 of file Chi2Fitter.h.

◆ Value() [2/2]

double Chi2Fitter::Value ( uint64_t index )

Get the best-fit value of ith parameter.

Parameters

index index of the parameter.

Returns: best-fit value of ith parameter.

Definition at line 231 of file Chi2Fitter.cxx.

Member Data Documentation

◆ chi2

double NAGASH::Chi2Fitter::chi2 = 0

private

Definition at line 81 of file Chi2Fitter.h.

◆ cov

TMatrixD NAGASH::Chi2Fitter::cov

private

Definition at line 80 of file Chi2Fitter.h.

◆ dimension

uint64_t NAGASH::Chi2Fitter::dimension = 1

private

Definition at line 70 of file Chi2Fitter.h.

◆ histtool

HistTool NAGASH::Chi2Fitter::histtool

private

Definition at line 84 of file Chi2Fitter.h.

◆ isvalid

bool NAGASH::Chi2Fitter::isvalid = false

private

Definition at line 69 of file Chi2Fitter.h.

◆ offset

double NAGASH::Chi2Fitter::offset = 0

private

Definition at line 82 of file Chi2Fitter.h.

◆ RangeMax

int NAGASH::Chi2Fitter::RangeMax = 1

private

Definition at line 72 of file Chi2Fitter.h.

◆ RangeMin

int NAGASH::Chi2Fitter::RangeMin = 1

private

Definition at line 71 of file Chi2Fitter.h.

◆ target

TH1D* NAGASH::Chi2Fitter::target = nullptr

private

Definition at line 73 of file Chi2Fitter.h.

◆ targetcov

TH2D* NAGASH::Chi2Fitter::targetcov = nullptr

private

Definition at line 74 of file Chi2Fitter.h.

◆ value

std::vector<double> NAGASH::Chi2Fitter::value

private

Definition at line 79 of file Chi2Fitter.h.

◆ vchi2

std::vector<double> NAGASH::Chi2Fitter::vchi2

private

Definition at line 75 of file Chi2Fitter.h.

◆ vvalue

std::vector<std::vector<double> > NAGASH::Chi2Fitter::vvalue

private

Definition at line 76 of file Chi2Fitter.h.

◆ vvaluemax

std::vector<double> NAGASH::Chi2Fitter::vvaluemax

private

Definition at line 77 of file Chi2Fitter.h.

◆ vvaluemin

std::vector<double> NAGASH::Chi2Fitter::vvaluemin

private

Definition at line 78 of file Chi2Fitter.h.

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

include/NAGASH/Chi2Fitter.h
src/Chi2Fitter.cxx

Classes

Public Types

Public Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ FitMethod

Constructor & Destructor Documentation

◆ Chi2Fitter() [1/2]

◆ Chi2Fitter() [2/2]

Member Function Documentation

◆ Cov()

◆ Error()

◆ Fit()

◆ FitChi2()

◆ GetChi2()

◆ OffSet()

◆ SetModel() [1/2]

◆ SetModel() [2/2]

◆ SetRange()

◆ Value() [1/2]

◆ Value() [2/2]

Member Data Documentation

◆ chi2

◆ cov

◆ dimension

◆ histtool

◆ isvalid

◆ offset

◆ RangeMax

◆ RangeMin

◆ target

◆ targetcov

◆ value

◆ vchi2

◆ vvalue

◆ vvaluemax

◆ vvaluemin