I've spent many hours on these parameters.

I changed them one by one and exhaustively all the possible combinations.

To my surprise, only "cp" will affect the performance of the classifier.

Others e.g. "maxsplit", etc. does not affect error rate at all.

I felt cheated by rpart.control().


On 3/11/06, Michael <comtech.usa@gmail.com> wrote:
>
>  Yes, rpart.control() has a bunch of parameters...
> I don't know which one can mostly improve the classification performance.
>
>
>  On 3/9/06, Carlos Ortega <coforfe@gmail.com> wrote:
> >
> >  Hello,
> >
> > Yes, check rpart.control() for details.
> >
> > Regards,
> >  Carlos.
> >
> >
> >  On 3/9/06, Michael <comtech.usa@gmail.com > wrote:
> > >
> > > I see! So you mean I have to collect error counts myself manually...
> > >
> > > By the way, what parameters do I normally change to improve the
> > > default rpart performance?
> > >
> > > Thanks a lot!
> > >
> > >
> > > On 3/8/06, Carlos Ortega <coforfe@gmail.com> wrote:
> > > >
> > > > Hello Michael,
> > > >
> > > > In some of the examples in the rpart function you will find that
> > > > comparison between the actual and the predicted values, although it is for
> > > > the "Classification" mode, not for the regression.
> > > >
> > > > Regards,
> > > > Carlos.
> > > >
> > > >
> > > >  On 3/7/06, Michael < comtech.usa@gmail.com > wrote:
> > > >
> > > > > Hi all,
> > > > >
> > > > >
> > > > >
> > > > > What parameter do I normally change in the rpart function? How do
> > > > > I set the
> > > > > "cp" option?
> > > > >
> > > > >
> > > > >
> > > > > Is there a way to read off error rate directly from the "rpart"
> > > > > function for
> > > > > training data; I imagine for testing data I have to apply a
> > > > > "predict", but
> > > > > for training data I guess the error count would be somewhere
> > > > > existing once
> > > > > the "rpart" function is finished. Looks like it is related to
> > > > > expressions
> > > > > such as "expected loss=0.8362365" when using "summary" function.
> > > > >
> > > > > Now I have to do this manually, and when it came to compare the
> > > > > correct vs.
> > > > > wrong and count the errors, it was always very tedious...
> > > > >
> > > > >
> > > > >
> > > > > Thanks a lot!
> > > > >
> > > > >
> > > > >
> > > > > M.
> > > > >
> > > > >        [[alternative HTML version deleted]]
> > > > >
> > > > > ______________________________________________
> > > > > R-help@stat.math.ethz.ch mailing list
> > > > > https://stat.ethz.ch/mailman/listinfo/r-help
> > > > > PLEASE do read the posting guide!
> > > > > http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> > > > >
> > > >
> > > >
> > >
> >
>

	[[alternative HTML version deleted]]


