[Rd] RE: cut.dendrogram (PR#1552)

[maechler@stat.math.ethz.ch]

>>>>> "MikG" == M GRUM <M.GRUM@CGIAR.ORG> writes:

    MikG> I'm resending this bug report with a new example.  As
    MikG> seen below, cut.dendrogram gives an error message for
    MikG> some heights, but not for others and with some
    MikG> datasets adn not others.  I can't see why.

    MikG> Last time I unwittingly sent my message with HTML
    MikG> formatting.  This time I'm travelling and using an
    MikG> e-mail system that I am unfamiliar with.  As far as I
    MikG> can see, I am not using HTML.

    <...example deleted..>

yes, this time your message has been very useful;
thank you, Mikkel!

Indeed, there is a (at least one!) problem in the  "dendrogram"
class/methods, currently --- which might not be so astonishing,
given the following excerpt from its documentation :

 >> dendrogram                package:mva                R Documentation
 >> 
 >> General Tree Structures
 >> 
 >> Description:
 >> 
 >>      Class `"dendrogram"' provides general functions for handling
 >>      tree-like structures.  It is intended as a replacement for similar
 >>      functions in hierarchical clustering and classification/regression
 >>      trees, such that all of these can use the same engine for plotting
 >>      or cutting trees. Currently the code is in alpha stage and the API
 >>      may change at any point in time.

 >> .............

 >> Details:
 >> 
 >>      Warning: This documentation is preliminary.

Really, it has been on my todo list to look into this, and at least
provide a few more methods, e.g. print(), str(), and maybe "[", "[[".
Also, as.dendrogram.<class> for "tree" and/or "rpart" and "VLMC"
objects.
As you may have read above, we have not even settled about
several details. {suggestions are welcome!}

BTW, in your example, even the first cut() result couldn't be
plotted any more.

We will look into this.
Thanks for the report!

Martin Maechler <maechler@stat.math.ethz.ch>	http://stat.ethz.ch/~maechler/
Seminar fuer Statistik, ETH-Zentrum  LEO C16	Leonhardstr. 27
ETH (Federal Inst. Technology)	8092 Zurich	SWITZERLAND
phone: x-41-1-632-3408		fax: ...-1228			<><

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