Plot a tree object on the current graphical device
# S3 method for tree
plot(x, y = NULL, type = c("proportional", "uniform"), ...)an object of class "tree".
ignored. Used for positional matching of type.
character string. If this partially matches
"uniform", the branches are of uniform
length. Otherwise they are proportional to the decrease in impurity.
graphical parameters.
An (invisible) list with components x and y
giving the coordinates of the tree nodes.
As a side effect, the value of type == "uniform" is stored in
the variable .Tree.unif.? in the global environment, where ?
is the device number.