R/projsplx.R

In maboost: Binary and Multiclass Boosting Algorithms

projsplx = function (y){

y=y;
m = length(y); bget = FALSE;

s = sort(y,decreasing=TRUE); 
tmpsum = 0;

for (ii in 1: (m-1)){
tmpsum = tmpsum + s[ii];
tmax = (tmpsum - 1)/ii;
if (tmax >= s[ii+1]){
bget = TRUE;
break
}
}

if (!bget){
  tmax =(tmpsum + s[m] -1)/m
} 
x=y-tmax;
x[which(x<0)]=0;

return(x)
}