[R] Surrogate splits for decision trees

[Thomas Lumley]

On Tue, 22 May 2001, Clayton Springer wrote:

> Dear R,
>
> Short verse of the question:
>
> Is there R code which will calculate surrogate splits
> and/or delta impurity for decision trees at each node?

package rpart

> Long Version:
>
> I have local, legacy code which I use to calculate my decision trees.
> I would like to switch to R, but as I understand it surrogate splits
> are not implemented.
>
> Surrogate splits and feature ranking are described in Breiman et al
> "CART" 1984.  Curiously, they don't seem to appear anywhere else
> in the literature.
>

The rpart package contains tree code that does implement surrogate splits.
It is not particularly extensible now, but the next version is planned to
be very extensible.


	-thomas

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