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R version 2.15.0 (2012-03-30)
Copyright (C) 2012 The R Foundation for Statistical Computing
ISBN 3-900051-07-0
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> library(rpart)
> require(survival)
Loading required package: survival
Loading required package: splines
> aeq <- function(x,y, ...) all.equal(as.vector(x), as.vector(y), ...)
> 
> #
> # Check out using costs
> #
> fit1 <- rpart(Surv(time, status) ~ age + sex + ph.ecog + ph.karno + pat.karno
+         + meal.cal + wt.loss, data=lung,
+         maxdepth=1, maxcompete=6, xval=0)
> 
> fit2 <- rpart(Surv(time, status) ~ age + sex + ph.ecog + ph.karno + pat.karno
+         + meal.cal + wt.loss, data=lung,
+         maxdepth=1, maxcompete=6, xval=0, cost=(1+ 1:7/10))
> 
> temp1 <- fit1$splits[1:7,]
> temp2 <- fit2$splits[1:7,]
> temp3 <- c('age', 'sex', 'ph.ecog', 'ph.karno', 'pat.karno', 'meal.cal',
+      'wt.loss')
> indx1 <- match(temp3, dimnames(temp1)[[1]])
> indx2 <- match(temp3, dimnames(temp2)[[1]])
> aeq(temp1[indx1,1], temp2[indx2,1])             #same n's ?
[1] TRUE
> aeq(temp1[indx1,3], temp2[indx2,3]*(1+ 1:7/10)) #scaled importance
[1] TRUE
> 
> 
> 
> proc.time()
   user  system elapsed 
  0.288   0.067   0.407