Re: [R] learning decision trees with one's own scoring functins

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Fri 26 Aug 2005 - 20:52:27 EST

Please do study the packages you mention a great deal more carefully before posting such negative remarks about them.

In particular, rpart is already fully user-extensible (and comes with a worked example), and both packages are supplied in source code on CRAN.

On Fri, 26 Aug 2005, zhihua li wrote:

> Hi netters,
>
> I want to learn a decision tree from a series of instances (learning data).
> The packages
> tree or rpart can do this quite well, but the scoring functions (splitting
> criteria) are
> fixed in these packages, like gini or something. However, I'm going to use
> another scoring
> function.
> At first I wanna modify the R code of tree or rpart and put my own scoring
> function in. But it seems that tree and rpart perform the splitting procedure
> by calling external C functions, which I have no access to. So do I have to
> write R code from scratch to build the tree with my own scoring functions?
> It's a really tough task. Or r there other R packages that can do similar
> things with more flexible and extensible code?
>
> Thanks a lot!
>
>

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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Received on Fri Aug 26 21:10:12 2005

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