separateData = function(dt, prop=c(2/3,1/6,1/6) ) {

### This function separates the entire dataframe into
### three parts: training, testing, and evaluating. 

  n = dim(dt)[1]
  all = 1:n
  ntrain = round(n*prop[1])
  sstrain = sample(n,ntrain)

  remaining = all[-sstrain]
  ntest = round(n*prop[2])
  sstest = sample(remaining,ntest)

  sseval = all[-c(sstest,sstrain)]

  res = list( train=dt[sstrain,],test=dt[sstest,],eval=dt[sseval,])

return(res)
}