From: Tak Kaneko (nospam@nospamcam.ac.uk)
Date: Tue 15 May 2001 - 07:31:30 EST
Message-ID: <Pine.SOL.4.33.0105142230380.10841-100000@green.csi.cam.ac.uk>
Is there a limit on how many features can be used to train a CART tree?
I built some trees using one set of features, which didn't perform very
well so I added some more (better) features but none of these got used in
training the tree. When I specified the tree to use the new features and
some of the old features, it finally used the new features and the
resulting trees performed well.
There are two alternative explanations I can think of:
1. There is only a maximum number of features that "tree" can utilise.
2. In the first few branches, the older features are used because they
reduce the deviance much more but actually on the long run, it's better to
use the new features.
It's probably bad practice just throwing lots of features any way but I'd
be grateful for some explanations!
tak
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