partimat function

Plotting the 2-d partitions of classification methods

Provides a multiple figure array which shows the classification of observations based on classification methods (e.g. lda, qda) for every combination of two variables. Moreover, the classification borders are displayed and the apparent error rates are given in each title.

partimat(x,...)

## Default S3 method:
partimat(x, grouping, method = "lda", prec = 100, 
    nplots.vert, nplots.hor, main = "Partition Plot", name, mar, 
    plot.matrix = FALSE, plot.control = list(), ...)
## S3 method for class 'data.frame'
partimat(x, ...)
## S3 method for class 'matrix'
partimat(x, grouping, ..., subset, na.action = na.fail)
## S3 method for class 'formula'
partimat(formula, data = NULL, ..., subset, na.action = na.fail)

Arguments

• x: matrix or data frame containing the explanatory variables (required, if formula is not given).
• grouping: factor specifying the class for each observation (required, if formula is not given).
• formula: formula of the form groups ~ x1 + x2 + .... That is, the response is the grouping factor and the right hand side specifies the (non-factor) discriminators.
• method: the method the classification is based on, currently supported are: lda, qda, rpart, naiveBayes, rda, sknn and svmlight

.

• prec: precision used to draw the classification borders (the higher the more precise; default: 100).

• data: Data frame from which variables specified in formula are preferentially to be taken.

• nplots.vert: number of rows in the multiple figure array

• nplots.hor: number of columns in the multiple figure array

• subset: index vector specifying the cases to be used in the training sample. (Note: If given, this argument must be named.)

• na.action: specify the action to be taken if NAs are found. The default action is for the procedure to fail. An alternative is na.omit, which leads to rejection of cases with missing values on any required variable. (Note: If given, this argument must be named.)

• main: title

• name: Variable names to be printed at the axis / into the diagonal.

• mar: numerical vector of the form c(bottom, left, top, right)

  which gives the lines of margin to be specified on the four sides of the plot. Defaults are rep(0, 4) if plot.matrix = TRUE, c(5, 4, 2, 1) + 0.1 otherwise.

• plot.matrix: logical; if TRUE, like a scatterplot matrix; if FALSE (default) uses less space and arranges the plots optimal

  (using a fuzzy algorithm) in an array by plotting each pair of variables once.

• plot.control: A list containing further arguments passed to the underlying plot functions (and to drawparti).

• ...: Further arguments passed to the classification method (through drawparti).

See Also

for much more fine tuning see drawparti

Author(s)

Karsten Luebke, karsten.luebke@fom.de , Uwe Ligges, Irina Czogiel

Note

Warnings such as parameter “xyz” couldn't be set in high-level plot function are expected, if making use of ....

Examples

library(MASS)
data(iris)
partimat(Species ~ ., data = iris, method = "lda")
## Not run:

partimat(Species ~ ., data = iris, method = "lda", 
    plot.matrix = TRUE, imageplot = FALSE) # takes some time ...
## End(Not run)