kde_bandwidth: Robust bandwidth estimation for kernel density estimation

In weird: Functions and Data Sets for "That's Weird: Anomaly Detection Using R" by Rob J Hyndman

Robust bandwidth estimation for kernel density estimation

Description

Bandwidth matrices are estimated in several ways including a normal reference rule, a robust version of the normal reference rule (default), a plugin estimator, or using the approach of Hyndman, Kandanaarachchi & Turner (2026). Details of each method are given in Hyndman (2026).

Usage

kde_bandwidth(data, method = c("robust", "normal", "plugin", "lookout"), ...)

Arguments

data	A numeric matrix or data frame.
method	A character string giving the method to use. Possibilities are: "normal" (normal reference rule), "robust" (a robust version of the normal reference rule, the default), "plugin" (a plugin estimator), and "lookout" (the bandwidth matrix estimate of Hyndman, Kandanaarachchi & Turner, 2026).
...	Additional arguments are ignored.

Value

A matrix of bandwidths (or a scalar in the case of univariate data).

Author(s)

Rob J Hyndman

References

Hyndman, R J, Kandanaarachchi, S & Turner, K (2026) "When lookout sees crackle: Anomaly detection via kernel density estimation", unpublished. https://robjhyndman.com/publications/lookout2.html

Hyndman, R J (2026) "That's weird: Anomaly detection using R", Section 2.7 and 3.9, https://OTexts.com/weird/.

Examples

# Univariate bandwidth calculation
kde_bandwidth(oldfaithful$duration)
# Bivariate bandwidth calculation
kde_bandwidth(oldfaithful[, c("duration", "waiting")])

weird documentation built on May 5, 2026, 9:06 a.m.