pdfCluster: plot.dbs – R documentation

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plot.dbs

Plot objects of class dbs

Description

This function provides a graphical tool to display diagnostics of density-based cluster analysis by means of the density-based silhouette information.

Usage

## S4 method for signature 'dbs'
plot(x, y , xlab = "", ylab = "", col = NULL, lwd = 3, cex = 0.9, 
    cex.axis = 0.5, main = NULL, labels = FALSE, ...)

Arguments

`x`	An object of `dbs-class;`
`y`	Not used; for compatibility with generic plot;
`xlab`	A title for the x axis;
`ylab`	A title for the y axis;
`col`	A specification for the plotting color. Default are colors in palette corresponding to the group labels;
`lwd`	A specification for the width of the bars in the plot;
`cex`	A numerical value giving the amount by which plotting text and symbols should be magnified relative to the default;
`cex.axis`	The magnification to be used for axis annotation relative to the current setting of cex;
`main`	An overall title for the plot;
`labels`	Logical. Should row index of data be added to the plot?
`...`	Further arguments to be passed to `plot`.

Details

After computing the density-based silhouette index by applying dbs-methods, data are partitioned into the clusters, sorted in a decreasing order with respect to their dbs value and displayed on a bar graph.

Methods

signature(x = "dbs", y = "missing"): S4 method for plotting objects of dbs-class

Examples

#example 1: no groups in data
#random generation of group labels
set.seed(54321)
x <- rnorm(50)
groups <- sample(1:2, 50, replace=TRUE)
groups
dsil <- dbs(x=as.matrix(x), clusters=groups)
dsil
summary(dsil)
plot(dsil, labels=TRUE, lwd=6)

#example 2: wines data
# load data
data(wine)

gr <- wine[,1]

# select a subset of variables
x <- wine[, c(2,5,8)]

#clustering
cl <- pdfCluster(x)
 
dsil <- dbs(cl)
plot(dsil)

pdfCluster

Cluster Analysis via Nonparametric Density Estimation

v1.0-3

GPL-2

Authors

Adelchi Azzalini, Giovanna Menardi for the current version; Adelchi Azzalini, Giovanna Menardi and Tiziana Rosolin up to version 0.1-13.

Initial release

2018-12-04