Chi2MinimumFinder1D Class Reference

Minimum finder using tabulated chi^2 values in one dimension. More...

#include <Chi2MinimumFinder1D.h>

Collaboration diagram for Chi2MinimumFinder1D:

Classes
struct	Minimum
	Result of minimum finder. More...

Public Member Functions
	Chi2MinimumFinder1D ()
	Default constructor.
	Chi2MinimumFinder1D (int nbins, double xmin, double xmax)
	Class constructor, similar to 1D histogram. More...
	Chi2MinimumFinder1D (const std::shared_ptr< TH1D > h)
	Constructor from a histogram.
void	clear ()
	Set chi^2 values to zero.
void	add (unsigned i, double chi2)
	Add chi^2 value to bin i. More...
Chi2MinimumFinder1D &	add (const Chi2MinimumFinder1D &other)
	Add data from another finder Finders must be defined with the same range and binning. More...
double	getXmin () const
	Returns lower limit of search region. More...
double	getXmax () const
	Returns upper limit of search region. More...
int	getNbins () const
	Returns number of bins. More...
double	getBinSize () const
	Returns bin (or step) size. More...
const std::vector< double > &	getBinCenters () const
	Returns vector of bin centers. More...
const std::vector< double > &	getChi2Values () const
	Returns vector of chi^2. More...
double	getMinChi2 () const
	Returns minimum chi2 value. More...
int	getEntries () const
	Returns number of entries (counted for bin 0) More...
const Minimum &	getMinimum ()
	Returns parabolic minimum.
TH1F	getHistogram (std::string name, std::string title) const
	Returns chi^2 packed into 1D histogram. More...

Private Member Functions
void	findMinimum ()
	Finds minimum.
Minimum	getMinimum (double yLeft, double yCenter, double yRight) const
	Calculates minimum using parabolic interpolation. More...

Private Attributes
double	m_xmin = 0
	lower limit of search region
double	m_xmax = 0
	upper limit of search region
double	m_dx = 0
	bin size
std::vector< double >	m_x
	bin centers
std::vector< double >	m_chi2
	chi^2 values at bin centers
int	m_entries = 0
	number of entries (counted for bin 0)
bool	m_searched = false
	internal flag
Minimum	m_minimum
	result: global minimum

Detailed Description

Minimum finder using tabulated chi^2 values in one dimension.

Definition at line 28 of file Chi2MinimumFinder1D.h.

Constructor & Destructor Documentation

Chi2MinimumFinder1D()

Chi2MinimumFinder1D	(	int	nbins,
		double	xmin,
		double	xmax
	)

Class constructor, similar to 1D histogram.

Parameters

nbins	number of points the search region is divided to
xmin	lower limit of the search region
xmax	upper limit of the search region

Definition at line 22 of file Chi2MinimumFinder1D.cc.

                                                                               :
      m_xmin(xmin), m_xmax(xmax)
    {
      if (nbins <= 0) {
        B2ERROR("Chi2MinimumFinder1D: nbins must be positive integer");
        return;
      }
      if (m_xmax <= m_xmin) {
        B2ERROR("Chi2MinimumFinder1D: search range max < min");
        return;
      }
      m_dx = (m_xmax - m_xmin) / nbins;
      double x = m_xmin + m_dx / 2;
      while (x < m_xmax) {
        m_x.push_back(x);
        x += m_dx;
      }
      m_chi2.resize(m_x.size(), 0);
    }

Member Function Documentation

add() [1/2]

Chi2MinimumFinder1D & add

(

const Chi2MinimumFinder1D &

other

)

Add data from another finder Finders must be defined with the same range and binning.

Returns

a reference to this finder

Definition at line 74 of file Chi2MinimumFinder1D.cc.

add() [2/2]

void add	(	unsigned	i,
		double	chi2
	)

Add chi^2 value to bin i.

Parameters

i	bin index (0-based)
chi2	value to be added

Definition at line 62 of file Chi2MinimumFinder1D.cc.

getBinCenters()

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

inline

Returns vector of bin centers.

Returns

bin centers

Definition at line 121 of file Chi2MinimumFinder1D.h.

{return m_x;}

getBinSize()

double getBinSize ( ) const

inline

Returns bin (or step) size.

Returns

bin size

Definition at line 115 of file Chi2MinimumFinder1D.h.

getChi2Values()

const std::vector<double>& getChi2Values ( ) const

inline

Returns vector of chi^2.

Returns

chi^2 values

Definition at line 127 of file Chi2MinimumFinder1D.h.

getEntries()

int getEntries ( ) const

inline

Returns number of entries (counted for bin 0)

Returns

number of entries

Definition at line 140 of file Chi2MinimumFinder1D.h.

getHistogram()

TH1F getHistogram	(	std::string	name,
		std::string	title
	)		const

Returns chi^2 packed into 1D histogram.

Parameters

name	histogram name
title	histogram title

Definition at line 126 of file Chi2MinimumFinder1D.cc.

getMinChi2()

double getMinChi2 ( ) const

inline

Returns minimum chi2 value.

Returns

minimum chi2 value

Definition at line 134 of file Chi2MinimumFinder1D.h.

getMinimum()

Chi2MinimumFinder1D::Minimum getMinimum ( double  yLeft, double  yCenter, double  yRight  ) const

private

Calculates minimum using parabolic interpolation.

Parameters

yLeft	bin content of left-to-minimal bin
yCenter	bin content of minimal bin
yRight	bin content of right-to-minimal bin

Returns

minimum given as a fraction of step to be added to central bin position

Definition at line 110 of file Chi2MinimumFinder1D.cc.

getNbins()

int getNbins ( ) const

inline

Returns number of bins.

Returns

number of bins

Definition at line 109 of file Chi2MinimumFinder1D.h.

getXmax()

double getXmax ( ) const

inline

Returns upper limit of search region.

Returns

xmax

Definition at line 103 of file Chi2MinimumFinder1D.h.

getXmin()

double getXmin ( ) const

inline

Returns lower limit of search region.

Returns

xmin

Definition at line 97 of file Chi2MinimumFinder1D.h.

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

• top/utilities/include/Chi2MinimumFinder1D.h
• top/utilities/src/Chi2MinimumFinder1D.cc