Contour plot of the skew skew-normal distribution in S^2: Contour plot of the skew skew-normal distribution in \(S^2\)
Description
Contour plot of the skew skew-normal distribution in \(S^2\).
Usage
skewnorm.contour(x, type = "alr", n = 100, appear = TRUE, cont.line = FALSE)
Arguments
x
A matrix with the compositional data. It has to be a 3 column matrix.
type
This is either "alr" or "ilr", corresponding to the additive and the isometric log-ratio transformation respectively.
n
The number of grid points to consider over which the density is calculated.
appear
Should the available data appear on the ternary plot (TRUE) or not (FALSE)?
cont.line
Do you want the contour lines to appear? If yes, set this TRUE.
Value
A ternary diagram with the points (if appear = TRUE) and the bivariate skew skew-normal contour lines.
Details
The alr or the ilr transformation is applied to the compositional data at first. Then for a grid of points within the 2-dimensional
simplex the bivariate skew skew-normal density is calculated and the contours are plotted along with the points.
References
Azzalini A. and Valle A. D. (1996). The multivariate skew-skewnormal distribution. Biometrika 83(4):715-726.
Aitchison J. (1986). The statistical analysis of compositional data. Chapman & Hall.