R/rankisub.R

In musto101/wilcox_R: What the package does (short line)

rankisub <-
function(x,y){
#
#  compute phat and an estimate of its variance
#
x<-x[!is.na(x)]  # Remove missing values from x
y<-y[!is.na(y)]  # Remove missing values from y
u<-outer(x,y,FUN="<")
p1<-0
p2<-0
for (j in 1:length(y)){
temp<-outer(u[,j],u[,j])
p1<-p1+sum(temp)-sum(u[,j]*u[,j])
}
for (i in 1: length(x)){
temp<-outer(u[i,],u[i,])
p2<-p2+sum(temp)-sum(u[i,]*u[i,])
}
p<-sum(u)/(length(x)*length(y))
pad<-p
if(p==0)pad<-.5/(length(x)*length(y))
if(p==1)pad<-(1-.5)/(length(x)*length(y))
p1<-p1/(length(x)*length(y)*(length(x)-1))
p2<-p2/(length(x)*length(y)*(length(y)-1))
var<-pad*(1.-pad)*(((length(x)-1)*(p1-p^2)/(pad*(1-pad))+1)/(1-1/length(y))+
((length(y)-1)*(p2-p^2)/(pad*(1-pad))+1)/(1-1/length(x)))
var<-var/(length(x)*length(y))
list(phat=p,sqse=var)
}