[R] R Weka and cobweb

Hans W. Borchers hwborchers at yahoo.de
Sun Aug 12 13:55:25 CEST 2007

 <adschai <at> optonline.net> writes:

> Hi,
> I never use cobweb before and I'm quite new to this. I have a couple of
questions around the cobweb
> implementation in R Weka. If you could supply answer or insight, I would
really appreciate.
> 1. From Fisher's paper in 1987, it seems that Cobweb only deals with nominal
data. In R Weka cobweb, is it
> allowed to accommodate real/continuous value?
> 2. My understanding is that Cobweb clusters based on Category Utility
function. However, if I would like to
> specify my own objective function, how can I do so?
> 3. I have about 130,000 data points (each with about 50 attributes) for
training and another same amount for
> testing. Would this cause any memory or performance problem?  
> Thank you,
> - adschai

RWeka is simply an interface to the WEKA data mining software.
Why don't you just put your question to the Weka mailing list
at https://list.scms.waikato.ac.nz/mailman/listinfo/wekalist?

>From my own former experience I would say that Cobweb is never
applicable to large data sets (and was not meant for that) and
for numerical attributes the results are not very meaningful.

Hans Werner Borchers

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