dist.fun.tricubic {som.nn}

Tricubic distance functions for topological k-NN classifier

Description

The tricubic function is used as distance-dependent weight w for k-NN voting.

Usage

dist.fun.tricubic(x, sigma = 1)

Arguments

x

Distance or numeric vector or matrix of distances.

sigma

Maximum distance to be considered.

Details

The function returns 1.0 for x = 0, 0.0 for x \ge \sigma and

w(x) = (1 - x^3 / \sigma^3)^3

for 0 < x < \sigma.

Value

  Distance-dependent weight.