MuonCalib::BaseFunctionFitter Class Reference

This class performs a fit of a linear combination of base functions to a set of sample points. More...

#include <BaseFunctionFitter.h>

Collaboration diagram for MuonCalib::BaseFunctionFitter:

Public Member Functions
	BaseFunctionFitter ()
	default constructor, the number of fit parameters will be set to 5
	BaseFunctionFitter (const unsigned nb_coefficients)
	constructor, the number of fit parameters is set to nb_coefficients
int	number_of_coefficients () const
	get the number of fit parameters (coefficients) of the base functions to be fitted
const Amg::VectorX &	coefficients () const
	get the coefficients determined by the fit to the sample points
void	set_number_of_coefficients (const unsigned nb_coefficients)
	set the number of fit parameters (coefficients) of the base functions to nb_coefficients
void	fit_parameters (const std::vector< SamplePoint > &sample_point, const unsigned int first_point, const unsigned int last_point, const BaseFunction &base_function)
	perform a fit of the base functions (base_function) to the sample points as given in "sample_point" starting at the sample point first_point and stopping at the point last_point, 1 <= first_point < last_point <= size of the sample_point vector; the method returns true, if the fit failed

Private Member Functions
void	init ()
	default initialization method
void	init (const unsigned nb_coefficients)
	initialization method: the number of fit parameters (coefficients) is set to nb_coefficients

Private Attributes
unsigned int	m_nb_coefficients {0}
	number of coefficients
Amg::MatrixX	m_A {}
	coefficient matrix for the fit
Amg::VectorX	m_alpha {}
	coefficients of the base functions after the fit
Amg::VectorX	m_b {}
	m_A*m_alpha = m_b;

Detailed Description

This class performs a fit of a linear combination of base functions to a set of sample points.

Definition at line 39 of file BaseFunctionFitter.h.

Constructor & Destructor Documentation

BaseFunctionFitter() [1/2]

MuonCalib::BaseFunctionFitter::BaseFunctionFitter

(

)

default constructor, the number of fit parameters will be set to 5

Definition at line 10 of file BaseFunctionFitter.cxx.

                                           {
        init();
    } 

BaseFunctionFitter() [2/2]

MuonCalib::BaseFunctionFitter::BaseFunctionFitter

(

const unsigned

nb_coefficients

)

constructor, the number of fit parameters is set to nb_coefficients

Definition at line 13 of file BaseFunctionFitter.cxx.

                                                                         {
        init(nb_coefficients);
    }

Member Function Documentation

coefficients()

const Amg::VectorX & MuonCalib::BaseFunctionFitter::coefficients

(

)

const

get the coefficients determined by the fit to the sample points

Definition at line 30 of file BaseFunctionFitter.cxx.

                                                             {
        return m_alpha;
    }

fit_parameters()

void MuonCalib::BaseFunctionFitter::fit_parameters	(	const std::vector< SamplePoint > &	sample_point,
		const unsigned int	first_point,
		const unsigned int	last_point,
		const BaseFunction &	base_function )

perform a fit of the base functions (base_function) to the sample points as given in "sample_point" starting at the sample point first_point and stopping at the point last_point, 1 <= first_point < last_point <= size of the sample_point vector; the method returns true, if the fit failed

Definition at line 36 of file BaseFunctionFitter.cxx.

                                                                               {
        if (first_point<1 || first_point>sample_point.size()) {
            THROW_EXCEPTION("BaseFunctionFitter::fit_parameters() - ERROR: Illegal first point "
                            <<first_point<<", must be >=1 and <="<<sample_point.size());
        }
        if (last_point<first_point || last_point>sample_point.size()) {
            THROW_EXCEPTION("BaseFunctionFitter::fit_parameters() - ERROR: Illegal last point "<<last_point
                          <<", must be >="<<first_point<<" and <="<<sample_point.size());
         }
        // clear the objects //
        init(m_nb_coefficients);
 
        for (unsigned j=0; j<m_nb_coefficients; ++j) {
            for (unsigned p=j; p<m_nb_coefficients; ++p) {
              for (unsigned k=first_point-1; k<last_point; ++k) {
                m_A.fillSymmetric(j,p,m_A(j,p)+base_function.value(j,sample_point[k].x1())
                                              *base_function.value(p,sample_point[k].x1()) /
                          std::pow(sample_point[k].error(), 2));
              }
            }
            for (unsigned k=first_point-1; k<last_point; k++) {
                 m_b[j] = m_b[j]+sample_point[k].x2()* base_function.value(j, sample_point[k].x1()) /
                          std::pow(sample_point[k].error(), 2);
            }
        }
        // perform the minimization //
        m_alpha = m_A.inverse()*m_b;
    }

init() [1/2]

void MuonCalib::BaseFunctionFitter::init ( )

private

default initialization method

Definition at line 16 of file BaseFunctionFitter.cxx.

{ init(5); }

init() [2/2]

void MuonCalib::BaseFunctionFitter::init ( const unsigned nb_coefficients )

private

initialization method: the number of fit parameters (coefficients) is set to nb_coefficients

Definition at line 18 of file BaseFunctionFitter.cxx.

                                                                {
        m_A = Amg::MatrixX(nb_coefficients,nb_coefficients);
        m_A.setZero();
        m_b = Amg::VectorX(nb_coefficients);
        m_b.setZero();
        m_alpha = Amg::VectorX(nb_coefficients);
        m_alpha.setZero();
        m_nb_coefficients = nb_coefficients;
    }

number_of_coefficients()

int MuonCalib::BaseFunctionFitter::number_of_coefficients

(

)

const

get the number of fit parameters (coefficients) of the base functions to be fitted

Definition at line 27 of file BaseFunctionFitter.cxx.

                                                         {
        return m_nb_coefficients;
    }

set_number_of_coefficients()

void MuonCalib::BaseFunctionFitter::set_number_of_coefficients

(

const unsigned

nb_coefficients

)

set the number of fit parameters (coefficients) of the base functions to nb_coefficients

Definition at line 33 of file BaseFunctionFitter.cxx.

                                                                                      {
        init(nb_coefficients);
    }

Member Data Documentation

m_A

Amg::MatrixX MuonCalib::BaseFunctionFitter::m_A {}

private

coefficient matrix for the fit

Definition at line 44 of file BaseFunctionFitter.h.

{}; 

m_alpha

Amg::VectorX MuonCalib::BaseFunctionFitter::m_alpha {}

private

coefficients of the base functions after the fit

Definition at line 45 of file BaseFunctionFitter.h.

{}; 

m_b

Amg::VectorX MuonCalib::BaseFunctionFitter::m_b {}

private

m_A*m_alpha = m_b;

Definition at line 46 of file BaseFunctionFitter.h.

{}; 

m_nb_coefficients

unsigned int MuonCalib::BaseFunctionFitter::m_nb_coefficients {0}

private

number of coefficients

Definition at line 43 of file BaseFunctionFitter.h.

{0}; 

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

• BaseFunctionFitter.h
• BaseFunctionFitter.cxx