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a961f8a1 BA |
1 | #' @include b_Algorithm.R |
2 | ||
3 | #' @title Regression Tree | |
4 | #' | |
5 | #' @description Regression Tree using the \code{tree} package. | |
6 | #' Inherits \code{\link{Algorithm}} | |
7 | #' | |
8 | #' @field nleaf Number of leaf nodes after pruning. Default: Inf (no pruning) | |
9 | #' | |
10 | RegressionTree = setRefClass( | |
11 | Class = "RegressionTree", | |
12 | ||
13 | fields = c( | |
14 | nleaf = "numeric" | |
15 | ), | |
16 | ||
17 | contains = "Algorithm", | |
18 | ||
19 | methods = list( | |
20 | initialize = function(...) | |
21 | { | |
22 | callSuper(...) | |
23 | if (length(nleaf) == 0 || nleaf < 1) | |
24 | nleaf <<- Inf | |
25 | }, | |
26 | predict_noNA = function(XY, x) | |
27 | { | |
28 | require(tree, quietly=TRUE) | |
29 | rt = tree(Measure ~ ., data=XY) | |
30 | treeSize = sum( rt$frame[["var"]] == "<leaf>" ) | |
31 | if (treeSize > nleaf) | |
32 | rt = prune.tree(rt, best = nleaf) | |
33 | return (stats::predict(rt, as.data.frame(x))) | |
34 | } | |
35 | ) | |
36 | ) |