R help - Jul 2004 - how to personalize split function in rpart

Hallo!
I am a student of the Politecnico di Milano (Milan, italy) and I'm working
on CARTs. I'm trying to use the R rpart function with a personalized
splitfunction... but I'm not able  to do it!
More precisely, I would like to know what is the meaning of the function
'init', 'split' and 'eval' named in the help page.I
can't find any answer
in 'Classification and regression trees' (Breiman, ...) , in 'Modern
applied statistics with S-plus' (Venables, Ripley) or even in the on-line
forum.Thank You very much
Simone Vantini

Have you looked at the package sources? Do read rpart/tests/usersplits.R.

On Mon, 5 Jul 2004, Simone Vantini wrote:
> I am a student of the Politecnico di Milano (Milan, italy) and I'm
working
> on CARTs. I'm trying to use the R rpart function with a personalized
splitfunction... but I'm not able  to do it!
> More precisely, I would like to know what is the meaning of the function
> 'init', 'split' and 'eval' named in the help page.I
can't find any answer
> in 'Classification and regression trees' (Breiman, ...) , in
'Modern
> applied statistics with S-plus' (Venables, Ripley) or even in the
on-line
> forum.Thank You very much
Those are not about rpart.  See the S original at

	http://www.mayo.edu/hsr/Sfunc.html

for some further details (in rpart/Manuscript/AddMethods, about adding 
C-level split functions).

-- 
Brian D. Ripley,                  ripley at 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