GiniIndex.cxx File Reference

#include "TMVA/GiniIndex.h"
#include "Rtypes.h"

Include dependency graph for GiniIndex.cxx:

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Functions
	ClassImp (TMVA::GiniIndex) Double_t TMVA
	Gini(Sample M) = 1 - (c(1)/N)^2 - (c(2)/N)^2 .... More...

Function Documentation

ClassImp

(

TMVA::GiniIndex

)

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

Definition at line 47 of file GiniIndex.cxx.