class TMVA::SeparationBase


An interface to calculate the "SeparationGain" for different
separation critiera 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 backgr), 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 crition which is optimized for when trying
to increase the information in the system (making the best selection


Function Members (Methods)

 
    This is an abstract class, constructors will not be documented.
    Look at the header to check for available constructors.

public:
virtual~SeparationBase()
static TClass*Class()
TStringGetName()
Double_tGetSeparationGain(const Double_t& nSelS, const Double_t& nSelB, const Double_t& nTotS, const Double_t& nTotB)
virtual Double_tGetSeparationIndex(const Double_t& s, const Double_t& b)
virtual TClass*IsA() const
TMVA::SeparationBase&operator=(const TMVA::SeparationBase&)
virtual voidShowMembers(TMemberInspector& insp, char* parent)
virtual voidStreamer(TBuffer& b)
voidStreamerNVirtual(TBuffer& b)

Data Members

protected:
TStringfNamename of the concrete Separation Index impementation

Class Charts

Inheritance Inherited Members Includes Libraries
Class Charts

Function documentation

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. into a "left-node" and a "right-node"
 (N * Index_parent) - (N_left * Index_left) - (N_right * Index_right)
 this is then the quality crition which is optimized for when trying
 to increase the information in the system (making the best selection
virtual ~SeparationBase()
 destructor
{}
Double_t GetSeparationIndex(const Double_t& s, const Double_t& b)
 Return the separation index (a measure for "purity" of the sample")
TString GetName()
 Return the name of the concrete Index implementation
{ return fName; }

Author: Andreas Hoecker, Joerg Stelzer, Helge Voss, Kai Voss
Last change: root/tmva $Id: SeparationBase.h 21630 2008-01-10 19:40:44Z brun $
Last generated: 2008-11-01 10:22
Copyright (c) 2005: *

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