Plot SVM Objects

Generates a scatter plot of the input data of a svm fit for classification models by highlighting the classes and support vectors. Optionally, draws a filled contour plot of the class regions.

# S3 method for svm
plot(x, data, formula, fill = TRUE, grid = 50, slice = list(),
symbolPalette = palette(), svSymbol = "x", dataSymbol = "o", ...)

Arguments

x

An object of class svm
data

data to visualize. Should be the same used for fitting.
formula

formula selecting the visualized two dimensions. Only needed if more than two input variables are used.
fill

switch indicating whether a contour plot for the class regions should be added.
grid

granularity for the contour plot.
slice

a list of named values for the dimensions held constant (only needed if more than two variables are used). The defaults for unspecified dimensions are 0 (for numeric variables) and the first level (for factors). Factor levels can either be specified as factors or character vectors of length 1.
symbolPalette

Color palette used for the class the data points and support vectors belong to.
svSymbol

Symbol used for support vectors.
dataSymbol

Symbol used for data points (other than support vectors).
...

additional graphics parameters passed to filled.contour and plot.

See also

svm

Examples

## a simple example
data(cats, package = "MASS")
m <- svm(Sex~., data = cats)
plot(m, cats)

## more than two variables: fix 2 dimensions
data(iris)
m2 <- svm(Species~., data = iris)
plot(m2, iris, Petal.Width ~ Petal.Length,
     slice = list(Sepal.Width = 3, Sepal.Length = 4))

## plot with custom symbols and colors
plot(m, cats, svSymbol = 1, dataSymbol = 2, symbolPalette = rainbow(4),
color.palette = terrain.colors)