dendrogram {mva} | R Documentation |
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.
plot.dendrogram(dobj, type=c("rectangle", "triangle"), center=FALSE, xlab="", ylab="", ...) as.dendrogram.hclust(object, ...) cut.dendrogram(dobj, h) plotNode(x1, x2, subtree, type, center) plotNodeLimit(x1, x2, subtree, center)
dobj |
Object of class "dendrogram" . |
type |
Type of plot. |
center |
If TRUE , nodes are plotted centered with respect to
the leaves in the branch. Default is to plot them in the middle of all
direct child nodes. |
h |
Height at which the tree is cutted. |
Warning: This documentation is preliminary.
The dendrogram is directly represented as a nested list, where each list
component corresponds to a branch of the tree. Hence, the first branch
of tree z
is z[[1]]
, the second branch of the
corresponding subtree is z[[1]][[2]]
etc.. Each node of the tree
carries some information needed for efficient plotting or cutting as
attributes:
members
height
midpoint
text
Terminal nodes (leaves of the tree) can have arbitrary value but must not be a list.
cut.dendrogram()
returns a list with components $upper
and
$lower
, the first is a truncated version of the original tree,
the latter a list with the branches obtained from cutting the tree.
plotNode()
and plotNodeLimit()
are helper functions.
library(mva) data(USArrests) hc <- hclust(dist(USArrests), "ave") str(dend1 <- as.dendrogram(hc)) plot(dend1) dend2 <- cut(dend1, h=70) plot(dend2$upper) plot(dend2$lower[[3]])