rdiric {VGAM} | R Documentation

## The Dirichlet distribution

### Description

Generates Dirichlet random variates.

### Usage

    rdiric(n, shape, dimension = NULL)

### Arguments

`n` | number of observations.
`shape` | the shape parameters. These must be positive. If `dimension` is specifed, values are recycled if necessary to length `dimension`.
`dimension` | the dimension of the distribution. If `dimension` is not numeric then it is taken to be `length(shape)`.

### Details

This function is based on a relationship between the gamma and Dirichlet distribution. Random gamma variates are generated, and then Dirichlet random variates are formed from these.

### Value

A `n` by `dimension` matrix of Dirichlet random variates. Each element is positive, and each row will sum to unity.

### Author(s)

Thomas W. Yee

### References

Lange, K. (2002) Mathematical and Statistical Methods for Genetic Analysis, 2nd ed. New York: Springer-Verlag.

### See Also

`dirichlet` is a VGAM family function for fitting a Dirichlet distribution to data.

### Examples

    y = rdiric(n=1000, shape=c(3, 1, 4))
    fit = vglm(y ~ 1, dirichlet, trace = TRUE, crit="c")
    Coef(fit)
    coef(fit, matrix=TRUE)

[Package VGAM version 0.7-9 Index]