AM_mix_components_prior_pois {AntMAN}

Generate a configuration object for a Poisson prior on the number of mixture components

Description

This function generates a configuration object for a Shifted Poisson prior on the number of mixture components such that

q_M(m)= Pr (M=m)= \frac{e^{-\Lambda}\Lambda^{m-1} }{(m-1)!} , \quad m=1,2,3,\ldots

The hyperparameter \Lambda can either be fixed using Lambda or assigned a Gamma(a,b) prior distribution with a and b. In AntMAN we assume the following parametrization of the Gamma density:

p(x\mid a,b )= \frac{b^a x^{a-1}}{\Gamma(a)} \exp\{ -bx \}, \quad x>0.

Usage

AM_mix_components_prior_pois(a = NULL, b = NULL, Lambda = NULL, init = NULL)

Arguments

a

The shape parameter a of the Gamma(a,b) prior distribution.

b

The rate parameter b of the Gamma(a,b) prior distribution.

Lambda

It allows to set the hyperparameter \Lambda to be assigned a fixed value.

init

The initial value for \Lambda, when specifying a and b.

Details

If no arguments are provided, the default is a prior distribution with a = 1 and b = 1.

Value

An AM_mix_components_prior object. This is a configuration list to be used as mix_components_prior argument for AM_mcmc_fit.

See Also

AM_mcmc_fit

Examples

components_prior = AM_mix_components_prior_pois (init=3,  a=1, b=1)