dist_tweedie: Tweedie Distribution

In tweedieDistr: Tweedie Distribution

Tweedie Distribution

Description

Construct a Tweedie distribution object using the compound Poisson–Gamma parameterisation with power parameter in (1, 2). The Tweedie family is a subclass of exponential dispersion models that naturally produces exact zeros (via the Poisson count component) mixed with continuous positive values (via the Gamma severity component), making it well suited to intermittent demand data.

Usage

dist_tweedie(mean = 1, dispersion = 1, power = 1.5)

Arguments

mean	Mean parameter \mu > 0.
dispersion	Dispersion parameter \phi > 0.
power	Power parameter p \in (1, 2).

Details

The density is evaluated using the series expansion of Dunn & Smyth (2005), implemented in C++ for performance.

Value

A distributional distribution object of class dist_tweedie.

References

Dunn, P. K., & Smyth, G. K. (2005). Series evaluation of Tweedie exponential dispersion model densities. Statistics and Computing, 15(4), 267–280. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1007/s11222-005-4070-y")}.

Examples

d <- dist_tweedie(mean = 2, dispersion = 0.8, power = 1.5)
d |> mean()
d |> quantile(c(0.5, 0.9))
d |> density(c(0, 1.5, 3))
d |> distributional::variance()
d |> distributional::generate(10)

tweedieDistr documentation built on July 23, 2026, 5:07 p.m.