Compositional (version 5.5)

Contour plot of the t distribution in S^2: Contour plot of the t distribution in \(S^2\)

Description

Contour plot of the t distribution in \(S^2\).

Usage

bivt.contour(x, type = "alr", n = 100, appear = TRUE, cont.line = FALSE)

Arguments

x

A matrix with 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 t contour lines.

Details

The alr or the ilr transformation is applied to the compositional data at first and the location, scatter and degrees of freedom of the bivariate t distribution are computed. Then for a grid of points within the 2-dimensional simplex the bivariate t density is calculated and the contours are plotted along with the points.

References

Aitchison J. (1986). The statistical analysis of compositional data. Chapman & Hall.

See Also

diri.contour, mix.compnorm.contour, compnorm.contour, skewnorm.contour

Examples

# NOT RUN {
x <- as.matrix( iris[, 1:3] )
x <- x / rowSums(x)
bivt.contour(x)
bivt.contour(x, type = "ilr")
# }