rDirichlet {compositions} | R Documentation

## Dirichlet distribution

### Description

The Dirichlet distribution on the simplex.

### Usage

    rDirichlet.acomp(n,alpha)
    rDirichlet.rcomp(n,alpha)

### Arguments

`n` | number of datasets to be simulated
`alpha` | parameters of the Dirichlet distribution

### Details

The Dirichlet distribution is the result of closing a vector of equally-scaled Gamma-distributed variables. It the conjugate prior distribution for a vector of probabilities of a multinomial distribution. Thus, it generalizes the beta distribution for more than two parts.

### Value

a generated random dataset of class `"acomp"` or `"rcomp"`, drawn from a Dirichlet distribution with the given parameter `alpha`. The names of `alpha` are used to name the parts.

### Author(s)

K.Gerald v.d. Boogaart http://www.stat.boogaart.de, Raimon Tolosana-Delgado

### References

Aitchison, J. (1986) The Statistical Analysis of Compositional Data Monographs on Statistics and Applied Probability. Chapman & Hall Ltd., London (UK). 416p.

Mateu-Figueras, G.; Pawlowsky-Glahn, V. (2005). The Dirichlet distribution with respect to the Aitchison measure on the simplex, a first approach. In: Mateu-Figueras, G. and Barcel'o-Vidal, C. (Eds.) Proceedings of the 2nd International Workshop on Compositional Data Analysis, Universitat de Girona, {ISBN} 84-8458-222-1, http://ima.udg.es/Activitats/CoDaWork05

### See Also

`rnorm.acomp`

### Examples

    tmp <- rDirichlet.acomp(10,alpha=c(A=2,B=0.2,C=0.2))
    plot(tmp)

[Package compositions version 0.91-6 Index]