R/sum.I.R

In mdbrown/survNRI: Estimate NRI for survival data

sum.I <-
function(yy,FUN,Yi,Vi=NULL)
  {
    if (FUN=="<"|FUN==">=") { yy <- -yy; Yi <- -Yi}
    pos <- rank(c(yy,Yi),ties.method='f')[1:length(yy)]-rank(yy,ties.method='f')
    if (substring(FUN,2,2)=="=") pos <- length(Yi)-pos
    if (!is.null(Vi)) {
        if(substring(FUN,2,2)=="=") tmpind <- order(-Yi) else  tmpind <- order(Yi)
       
        Vi <- apply(as.matrix(Vi)[tmpind,,drop=F],2,cumsum)
        return(rbind(0,Vi)[pos+1,])
    } else return(pos)
  }