R/dea_est.R

In npbr: Nonparametric Boundary Regression

 dea_est<-function(xtab, ytab, x, type = "dea"){
   
  # verification
  stopifnot(type%in%c("dea", "fdh", "lfdh"), length(xtab)==length(ytab))
 
  if(type=="dea"){
    res <- (dea(x, rep(median(ytab), length(x)), XREF = xtab, YREF = ytab, RTS = 1, ORIENTATION = "out")$eff)*median(ytab)
    }else
     {if(type=="fdh"){
       res <- (dea(x, rep(median(ytab), length(x)), XREF = xtab, YREF = ytab, RTS = 0, ORIENTATION = "out")$eff)*median(ytab)
     }else
      {fdh_index <- which(dea(xtab, ytab, RTS = 0, ORIENTATION = "out")$eff==1)
       itp <- approx(x = xtab[fdh_index], y = ytab[fdh_index], x, method = "linear", yleft = min(ytab[fdh_index]),
                     yright = max(ytab[fdh_index]))
       res <- itp$y
      }
     }
   return(res)
 }