R: Plot a varmod object (created by calling earth with the...

plot.varmod {earth}

R Documentation

Plot a varmod object (created by calling earth with the varmod argument)

Description

Plot a variance model (a varmod object).

Typically you call this function for a variance model embedded in an earth model.

Usage

## S3 method for class 'varmod'
plot(x = stop("no 'x' argument"), which = 1:4,
  do.par = NULL, info=FALSE,
  cex = NULL, caption = NULL,
  line.col = 2, min.sd.col = line.col,
  trace = 0, ...)

Arguments

`x`	A `varmod` object. Typically this is embedded in a parent `earth` object, and so you invoke this function with `plot(earth.mod$varmod)`. The `varmod.method` argument must have been specified when building the `earth` model.
`which`	Which plots to plot. Default is 1:4 meaning all. The term parent below refers to the `earth` model in which the `varmod` is embedded. 1) fitted vs parent fitted 2) fitted vs parent first predictor 3) residuals vs fitted 4) model selection graph (only when `varmod.method="earth"` or `"x.earth"`).
`do.par`	Please see `plotres`
`info`	Plot some additional information, including lowess fits in the first two plots.
`cex`	Character expansion.
`caption`	Default is NULL, meaning automatically generate an overall caption.
`line.col`	Color of lines in the plots. Default is `red`.
`min.sd.col`	Color of the `min.sd` dotted horizontal line. Default is `line.col`. Use `0` to not plot this line.
`trace`, `...`	Similar to `plotres`

Note

The horizontal red dotted line in the first two plots shows the value of min.sd. See earth's varmod.clamp argument.

Examples

data(ozone1)

set.seed(1) # optional, for cross validation reproducibility

# note: should really use ncross=30 below but for a quick demo we don't

earth.mod <- earth(O3~temp, data=ozone1, nfold=10, ncross=3, varmod.method="lm")

plot(earth.mod$varmod) # plot the embedded variance model (this calls plot.varmod)