# triplot: Plot density of a 3D hyperdirichlet distribution In hyperdirichlet: A Generalization of the Dirichlet Distribution

## Description

Plot (log) density of a 3D hyperdirichlet distribution

## Usage

 `1` ```triplot(HD, l = 100, do_image=TRUE, do_contour=TRUE, discard = 0.05, labels=NULL, ...) ```

## Arguments

 `HD` Either a function of a three-element vector, or a hyperdirichlet object `l` Size of plot; larger values look much better but take longer `do_image,do_contour` Boolean, indicating whether to plot the image and contour respectively `discard` Numeric; default 0.05 means to disregard densities less than the fifth percentile (i.e. quantile 0.05). This makes the contour plot intervals prettier `labels` Length three character vector for corner labels with default `NULL` meaning to use `pnames(HD)` `...` Further arguments passed to `image()` and `contour()`

## Details

If argument `HD` is not a function it is interpreted as a hyperdirichlet object. If `HD` is a function, `triplot()` will pass it a three-element vector.

If argument `HD` is a hyperdirichlet object, then `triplot()` plots contours of the log of the density (ie support). If you want likelihood instead, see examples section for how to do this.

Labels will be printed at the appropriate corners; use `par(xpd=TRUE)` to suppress clipping.

## Value

The function returns (invisibly) an `l`-by-`l` matrix holding the support as a function of the two independent variables, with `NA` outside the domain.

## Author(s)

Robin K. S. Hankin

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18``` ```a <- dirichlet(1:3) triplot(a,l=20) old.par <- par(no.readonly=TRUE);par(xpd=TRUE) # (needed for labels) pnames(a) <- letters[1:3] triplot(a,l=33) f <- function(p){1-p[1]+p[2]+8*p[2]^2*p[3]} triplot(f,labels=LETTERS[1:3]) g <- function(p){dhyperdirichlet(p, a, log=FALSE)} triplot(g,l=20) par(old.par) ```

hyperdirichlet documentation built on May 31, 2017, 5:18 a.m.