Compute the Epanechnikov function

The Epanechnikov function is one of the quadratic kernels used in kernel density estimation. It is defined as follows: $$K(x) = \frac{3}{4}(1 - x^2) \quad \text{if} \quad |x| \leq 1\text{.}$$

Usage

compute_epanechnikov(x)

Arguments

x

A numeric vector.

Value

A numeric vector of weights of the kernel for each input points.

Examples

x <- seq(-3, 3, 0.1)
y <- compute_epanechnikov(x)
plot(x, y, xlim = c(-3, 3), ylim = c(0, 1), type = "l")