# Dirichlet: Dirichlet distribution In extraDistr: Additional Univariate and Multivariate Distributions

## Description

Density function, cumulative distribution function and random generation for the Dirichlet distribution.

## Usage

 ```1 2 3``` ```ddirichlet(x, alpha, log = FALSE) rdirichlet(n, alpha) ```

## Arguments

 `x` k-column matrix of quantiles. `alpha` k-values vector or k-column matrix; concentration parameter. Must be positive. `log` logical; if TRUE, probabilities p are given as log(p). `n` number of observations. If `length(n) > 1`, the length is taken to be the number required.

## Details

Probability density function

f(x) = Γ(sum(α[k])) / prod(Γ(α[k])) * prod(x[k]^{k-1})

## References

Devroye, L. (1986). Non-Uniform Random Variate Generation. Springer-Verlag.

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10``` ```# Generating 10 random draws from Dirichlet distribution # parametrized using a vector rdirichlet(10, c(1, 1, 1, 1)) # or parametrized using a matrix where each row # is a vector of parameters alpha <- matrix(c(1, 1, 1, 1:3, 7:9), ncol = 3, byrow = TRUE) rdirichlet(10, alpha) ```

extraDistr documentation built on Sept. 7, 2020, 5:09 p.m.