cforest prints empty tree

Question

I\'m trying to use cforest function(R, party package).

This\'s what I do to construct forest:

library(\"party\")
set.seed(42)
readingSkills.cf <-          


        

Answer 1

The solution proposed by @rcs in the Update is interesting but does not work with cforest when the dependent variable is numerical. The code:

set.seed(12345)
y <- cforest(score ~ ., data = readingSkills,
       control = cforest_unbiased(mtry = 2, ntree = 50))
tr <- party:::prettytree(y@ensemble[[1]], names(y@data@get("input")))
tr_weights <- update_tree(tr)
plot(new("BinaryTree", tree=tr_weights, data=y@data, responses=y@responses))

generates the following error message

R> Error in valid.data(rep(units, length.out = length(x)), data) :
   no string supplied for 'strwidth/height' unit

and the following plot:

Below I suggest an improved version of the hack proposed by @rcs:

get_cTree <- function(cf, k=1) {
  dt <- cf@data@get("input")
  tr <- party:::prettytree(cf@ensemble[[k]], names(dt))
  tr_updated <- update_tree(tr, dt)
  new("BinaryTree", tree=tr_updated, data=cf@data, responses=cf@responses, 
      cond_distr_response=cf@cond_distr_response, predict_response=cf@predict_response)
}

update_tree <- function(x, dt) {
  x <- update_weights(x, dt)
  if(!x$terminal) {
    x$left <- update_tree(x$left, dt)
    x$right <- update_tree(x$right, dt)   
  } 
  x
}

update_weights <- function(x, dt) {
  splt <- x$psplit
  spltClass <- attr(splt,"class")
  spltVarName <- splt$variableName
  spltVar <- dt[,spltVarName]
  spltVarLev <- levels(spltVar)
  if (!is.null(spltClass)) {
    if (spltClass=="nominalSplit") {
     attr(x$psplit$splitpoint,"levels") <- spltVarLev   
     filt <- spltVar %in% spltVarLev[as.logical(x$psplit$splitpoint)] 
    } else {
     filt <- (spltVar <= splt$splitpoint)
    }
  x$left$weights <- as.numeric(filt)
  x$right$weights <- as.numeric(!filt)
  }
  x
}

plot(get_cTree(y, 1))