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Create a Kernel Specification

Source: R/kernels.R
kernel_spec.Rd

Constructs a kernel specification object used throughout kernR for computing kernel matrices. Supports RBF (Gaussian), Matern, linear, and polynomial kernels.

Usage

kernel_spec(
  type = c("rbf", "matern", "linear", "polynomial"),
  bandwidth = "median",
  nu = 2.5,
  degree = 2L,
  offset = 1
)

Arguments

type

Character. Kernel type: "rbf" (default), "matern", "linear", or "polynomial".

bandwidth

Numeric or "median". Lengthscale parameter for RBF and Matern kernels. If "median" (default), the median heuristic is used to select bandwidth automatically from the data.

nu

Numeric. Smoothness parameter for the Matern kernel. Common choices: 0.5 (Laplace), 1.5, 2.5, Inf (RBF). Default is 2.5.

degree

Integer. Degree for polynomial kernel. Default is 2.

offset

Numeric. Offset for polynomial kernel. Default is 1.

Value

An object of class "kernel_spec".

See also

Other kernel primitives: kernel_matrix(), resolve_bandwidth(), select_bandwidth(), weighted_hsic_stat()

Examples

# Default RBF kernel with median heuristic bandwidth
k <- kernel_spec()

# RBF with fixed bandwidth
k <- kernel_spec("rbf", bandwidth = 1.0)

# Matern kernel
k <- kernel_spec("matern", nu = 1.5)

# Linear kernel (no bandwidth needed)
k <- kernel_spec("linear")