ROOT   6.14/05 Reference Guide
TMVA::SeparationBase Class Referenceabstract

An interface to calculate the "SeparationGain" for different separation criteria used in various training algorithms.

There are two things: the Separation Index, and the Separation Gain Separation Index: Measure of the "purity" of a sample. If all elements (events) in the sample belong to the same class (e.g. signal or background), than the separation index is 0 (meaning 100% purity (or 0% purity as it is symmetric. The index becomes maximal, for perfectly mixed samples eg. purity=50% , N_signal = N_bkg

Separation Gain: the measure of how the quality of separation of the sample increases by splitting the sample e.g. into a "left-node" and a "right-node" (N * Index_parent) - (N_left * Index_left) - (N_right * Index_right) this is then the quality criterion which is optimized for when trying to increase the information in the system (making the best selection

Definition at line 82 of file SeparationBase.h.

## Public Member Functions

SeparationBase ()
Constructor. More...

SeparationBase (const SeparationBase &s)
Copy constructor. More...

virtual ~SeparationBase ()

const TStringGetName ()

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. More...

virtual Double_t GetSeparationIndex (const Double_t s, const Double_t b)=0

## Protected Attributes

TString fName

Double_t fPrecisionCut

#include <TMVA/SeparationBase.h>

Inheritance diagram for TMVA::SeparationBase:
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## ◆ SeparationBase() [1/2]

 TMVA::SeparationBase::SeparationBase ( )

Constructor.

Definition at line 76 of file SeparationBase.cxx.

## ◆ SeparationBase() [2/2]

 TMVA::SeparationBase::SeparationBase ( const SeparationBase & s )

Copy constructor.

Definition at line 86 of file SeparationBase.cxx.

## ◆ ~SeparationBase()

 virtual TMVA::SeparationBase::~SeparationBase ( )
inlinevirtual

Definition at line 93 of file SeparationBase.h.

## ◆ GetName()

 const TString& TMVA::SeparationBase::GetName ( )
inline

Definition at line 104 of file SeparationBase.h.

## ◆ GetSeparationGain()

 Double_t TMVA::SeparationBase::GetSeparationGain ( const Double_t nSelS, const Double_t nSelB, const Double_t nTotS, const Double_t nTotB )
virtual

Separation Gain: the measure of how the quality of separation of the sample increases by splitting the sample e.g.

into a "left-node" and a "right-node" (N * Index_parent) - (N_left * Index_left) - (N_right * Index_right) this is then the quality criterion which is optimized for when trying to increase the information in the system (making the best selection

Reimplemented in TMVA::SdivSqrtSplusB.

Definition at line 101 of file SeparationBase.cxx.

## ◆ GetSeparationIndex()

 virtual Double_t TMVA::SeparationBase::GetSeparationIndex ( const Double_t s, const Double_t b )
pure virtual

## ◆ fName

 TString TMVA::SeparationBase::fName
protected

Definition at line 108 of file SeparationBase.h.

## ◆ fPrecisionCut

 Double_t TMVA::SeparationBase::fPrecisionCut
protected

Definition at line 110 of file SeparationBase.h.

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