agnes.object: Agglomerative Nesting Object
Description
The objects of class "agnes"
represent an agglomerative hierarchical clustering of a dataset.Value
- A legitimate
agnes object is a list with the following components: - ordera vector giving a permutation of the original observations to allow
for plotting, in the sense that the branches of a clustering tree
will not cross.
- order.laba vector similar to
order, but containing observation labels
instead of observation numbers. This component is only available if
the original observations were labelled. - heighta vector with the distances between merging clusters at the successive
stages.
- acthe agglomerative coefficient, measuring the clustering structure of the
dataset.
For each observation i, denote by m(i) its dissimilarity to the
first cluster it is merged with, divided by the dissimilarity of the
merger in the final step of the algorithm. The
ac is the
average of all 1 - m(i). It can also be seen as the average width
(or the percentage filled) of the banner plot. Because ac
grows with the number of observations, this measure should not
be used to compare datasets of very different sizes. - mergean (n-1) by 2 matrix, where n is the number of observations. Row i
of
merge describes the merging of clusters at step i of the
clustering. If a number j in the row is negative, then the single
observation |j| is merged at this stage. If j is positive, then the
merger is with the cluster formed at stage j of the algorithm. - dissan object of class
"dissimilarity" (see
dissimilarity.object), representing the total
dissimilarity matrix of the dataset. - dataa matrix containing the original or standardized measurements, depending
on the
stand option of the function agnes. If a
dissimilarity matrix was given as input structure, then this
component is not available.
GENERATION
This class of objects is returned from agnes.METHODS
The "agnes" class has methods for the following generic functions:
print, summary, plot.INHERITANCE
The class "agnes" inherits from "twins".
Therefore, the generic function pltree can be used on an
agnes object.