| library: libTMVA #include "GiniIndex.h" |
| Inheritance Chart: | |||||||||
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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) )