TMVA::GiniIndex Class Reference

Implementation of the GiniIndex as separation criterion.

Large Gini Indices (maximum 0.5) mean , that the sample is well mixed (same amount of signal and bkg) bkg.

Small Indices mean, well separated.

General definition:

\[ Gini(Sample M) = 1 - (\frac{c(1)}{N})^2 - (\frac{c(2)}{N})^2 .... - (\frac{c(k)}{N})^2 \]

Where:

\( M \) is a sample of whatever \( N \) elements (events) that belong to \( K \) different classes.

\( c(k) \) is the number of elements that belong to class \( k \) for just Signal and Background classes this boils down to:

\[ Gini(Sample) = \frac{2sb}{(s+b)^2} \]

Definition at line 63 of file GiniIndex.h.

Public Member Functions
	GiniIndex ()
	GiniIndex (const GiniIndex &g)
virtual	~GiniIndex ()
virtual Double_t	GetSeparationIndex (const Double_t s, const Double_t b)
	what we use here is 2*Gini.
virtual TClass *	IsA () const
virtual void	Streamer (TBuffer &)
void	StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)
Public Member Functions inherited from TMVA::SeparationBase
	SeparationBase ()
	Constructor.
	SeparationBase (const SeparationBase &s)
	Copy constructor.
virtual	~SeparationBase ()
const TString &	GetName ()
virtual Double_t	GetSeparationGain (const Double_t nSelS, const Double_t nSelB, const Double_t nTotS, const Double_t nTotB)
	Separation Gain: the measure of how the quality of separation of the sample increases by splitting the sample e.g.
void	StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

Static Public Member Functions
static TClass *	Class ()
static const char *	Class_Name ()
static constexpr Version_t	Class_Version ()
static const char *	DeclFileName ()
Static Public Member Functions inherited from TMVA::SeparationBase
static TClass *	Class ()
static const char *	Class_Name ()
static constexpr Version_t	Class_Version ()
static const char *	DeclFileName ()

Additional Inherited Members
Protected Attributes inherited from TMVA::SeparationBase
TString	fName
Double_t	fPrecisionCut

#include <TMVA/GiniIndex.h>

Inheritance diagram for TMVA::GiniIndex:

Constructor & Destructor Documentation

GiniIndex() [1/2]

TMVA::GiniIndex::GiniIndex ( )

inline

Definition at line 68 of file GiniIndex.h.

GiniIndex() [2/2]

TMVA::GiniIndex::GiniIndex ( const GiniIndex & g )

inline

Definition at line 71 of file GiniIndex.h.

~GiniIndex()

virtual TMVA::GiniIndex::~GiniIndex ( )

inlinevirtual

Definition at line 74 of file GiniIndex.h.

Member Function Documentation

Class()

static TClass * TMVA::GiniIndex::Class ( )

static

Returns

TClass describing this class

Class_Name()

static const char * TMVA::GiniIndex::Class_Name ( )

static

Returns

Name of this class

Class_Version()

static constexpr Version_t TMVA::GiniIndex::Class_Version ( )

inlinestaticconstexpr

Returns

Version of this class

Definition at line 81 of file GiniIndex.h.

DeclFileName()

static const char * TMVA::GiniIndex::DeclFileName ( )

inlinestatic

Returns

Name of the file containing the class declaration

Definition at line 81 of file GiniIndex.h.

GetSeparationIndex()

Double_t TMVA::GiniIndex::GetSeparationIndex ( const Double_t s, const Double_t b )

virtual

what we use here is 2*Gini.

. as for the later use the factor 2 is irrelevant and hence I'd like to save this calculation

Implements TMVA::SeparationBase.

Definition at line 76 of file GiniIndex.cxx.

IsA()

virtual TClass * TMVA::GiniIndex::IsA ( ) const

inlinevirtual

Returns

TClass describing current object

Reimplemented from TMVA::SeparationBase.

Definition at line 81 of file GiniIndex.h.

Streamer()

virtual void TMVA::GiniIndex::Streamer ( TBuffer & )

virtual

Reimplemented from TMVA::SeparationBase.

StreamerNVirtual()

void TMVA::GiniIndex::StreamerNVirtual ( TBuffer & ClassDef_StreamerNVirtual_b )

inline

Definition at line 81 of file GiniIndex.h.

Libraries for TMVA::GiniIndex:

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

• tmva/tmva/inc/TMVA/GiniIndex.h
• tmva/tmva/src/GiniIndex.cxx