library: libTMVA #include "GiniIndex.h" |
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protected:
virtual Double_t GetSeparationIndex(const Double_t& s, const Double_t& b) public:
GiniIndex() GiniIndex(const TMVA::GiniIndex&) virtual ~GiniIndex() static TClass* Class() virtual TClass* IsA() const TMVA::GiniIndex& operator=(const TMVA::GiniIndex&) virtual void ShowMembers(TMemberInspector& insp, char* parent) virtual void Streamer(TBuffer& b) void StreamerNVirtual(TBuffer& b)
_______________________________________________________________________ Implementation of the GiniIndex as separation criterion _______________________________________________________________________
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) )