R/Gini_CTR_BS.R

In GiniWegNeg: Computing the Gini-Based Coefficients for Weighted and Negative Attributes

Gini_CTR_BS <-
function(y,w=rep(1,length(y)))
{
dataset<-cbind(y,w)
ord_y<-order(y)
dataset_ord<-dataset[ord_y,]
y<-dataset_ord[,1]
w<-dataset_ord[,2]
N<-sum(w)
yw<-y*w
C_i<-cumsum(w)
num_1<-sum(yw*C_i)
num_2<-sum(yw)
num_3<-sum(yw*w)
G_num<-(2/N^2)*num_1-(1/N)*num_2-(1/N^2)*num_3
VectYMin<-function(yw)
{
yw<-sort(yw)
cumsum(yw)
step_Y<-cumsum(yw)<0
VectYMin<-yw[step_Y]
VectYMin
}
Y_neg<-VectYMin(yw)
k_y<-length(Y_neg)
k1_y<-k_y+1
y_k1<-y[k1_y]
C_i_k<-C_i[1:k_y]
y_y<-y[c(1:k_y)]
yw_k<-yw[c(1:k_y)]
w_k<-w[c(1:k_y)]
m_y<-(sum(yw)/N)
den_1<-sum(yw_k*C_i_k)
den_2<-sum(yw_k)
den_3<-((den_2/y_k1)-2*sum(w_k))
den_4<-sum(yw_k*w_k)
G_BS_den<-m_y+(2/N^2)*den_1+(1/N^2)*den_2*den_3-(1/N^2)*den_4
if (m_y<=0) {G_BS_den<-G_num} else {G_BS_den}; 
if (k_y==0) {G_BS_den<-m_y} else {G_BS_den}
G_CTR_BS<-G_num/G_BS_den
list(GINI_CTR_BS=G_CTR_BS)
}