Computes the periodic covariance function:
$$k(s, t) = \sigma^2 \exp\left(-\frac{2\sin^2(\pi|s-t|/p)}{\ell^2}\right)$$
Usage
kernel.periodic(variance = 1, length_scale = 1, period = 1)
Value
A covariance function object of class 'kernel_periodic'.
Arguments
variance
Variance parameter \(\sigma^2\) (default 1).
length_scale
Length scale parameter \(\ell\) (default 1).
period
Period parameter \(p\) (default 1).
Details
The periodic covariance function produces sample paths that are periodic
with the specified period. It is useful for modeling seasonal or cyclical
patterns in functional data.