dot-cor_cauchy function

Calculate Cauchy correlation

Calculate Cauchy correlation

.cor_cauchy(x, a, alpha, nu = 1, nugget = 0)

Arguments

  • x: A numeric vector, matrix, or array.
  • a: Smooth parameter, a>0a>0.
  • alpha: Scale parameter, α(0,1]\alpha\in(0, 1].
  • nu: Power parameter, ν>0\nu>0. Default is 1.
  • nugget: The nugget effect [0,1]\in[0, 1].

Returns

Correlations of the same dimension as x.

Details

The Cauchy correlation function with scale parameter aa and smooth parameter α\alpha has the form

C(x)=(1nugget)(ax2α+1)ν+nuggetδx=0, C(x)=(1-\text{nugget})(a|x|^{2\alpha} + 1)^{-\nu}+\text{nugget}\cdot\delta_{x=0},

where δx=0\delta_{x=0} is 1 when x=0x=0 and 0 otherwise.

References

Gneiting, T., and Schlather, M. (2004). Stochastic Models That Separate Fractal Dimension and the Hurst Effect. SIAM Review, 46(2), 269–282.