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class TMVA::GiniIndex: public TMVA::SeparationBase

 Implementation of the GiniIndex as separation criterion

Function Members (Methods)

Data Members

TStringTMVA::SeparationBase::fNamename of the concrete Separation Index impementation

Class Charts

Inheritance Inherited Members Includes Libraries
Class Charts

Function documentation

Double_t GetSeparationIndex(const Double_t& s, const Double_t& b)
     Gini(Sample M) = 1 - (c(1)/N)^2 - (c(2)/N)^2 .... - (c(k)/N)^2
     Where: M is a smaple 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) = 2s*b/(s+b)^2    ( = 2 * purity * (1-purity) )

 !! 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
 construtor for the GiniIndex
{ fName="Gini"; }
GiniIndex(const TMVA::GiniIndex& g)
 copy constructor
virtual ~GiniIndex()