cor_cauchy function

Calculate Cauchy correlation

Calculate Cauchy correlation

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

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].
  • is.dist: Logical; if TRUE, x is a distance matrix or an array of distance matrices.

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.

Examples

x <- matrix(c(0, 5, 5, 0), nrow = 2) cor_cauchy(x, a = 1, alpha = 0.5) x <- matrix(c(0, 5, 5, 0), nrow = 2) cor_cauchy(x, a = 1, alpha = 0.5, nugget = 0.3, is.dist = TRUE)

References

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

See Also

Other correlation functions: cor_exp(), cor_fs(), cor_lagr_askey(), cor_lagr_exp(), cor_lagr_tri(), cor_sep(), cor_stat(), cor_stat_rs()