R/cr.forward.R

In glmpathcr: Fit a Penalized Continuation Ratio Model for Predicting an Ordinal Response

cr.forward <-
function(x,y,weight) {
    yname <- as.character(substitute(y))
    if (!is.factor(y)) 
        y <- factor(y, exclude = NA)
    ylevels <- levels(y)
    kint <- length(ylevels) - 1
    y <- as.integer(y)
    names<-dimnames(x)[[2]]
	if (length(names)==0) names<-paste("V",1:dim(x)[2],sep="")
    expand<-list()
    for (k in 1:kint) {    
       expand[[k]]<-cbind(y[is.element(y,k:(kint+1))],weight[is.element(y,k:(kint+1))],x[is.element(y,k:(kint+1)),])
       expand[[k]][,1]<-ifelse(expand[[k]][,1]==k,1,0)
       cp<-matrix(rep(0,dim(expand[[k]])[1]*kint),ncol=kint)
       cp[,k]<-1
       dimnames(cp)[[2]]<-paste("cp",1:kint,sep="")
       expand[[k]]<-cbind(expand[[k]],cp)
	   dimnames(expand[[k]])[[2]]<-c("y","weight",names,paste("cp",1:kint,sep=""))
    } 
	newx<-expand[[1]]
	for (k in 2:kint)  newx<-rbind(newx,expand[[k]])
    newx
}