initialize_pts: Initialize auxiliary variables given theta

In pierrejacob/montecarlodsm: Gibbs sampler for Dempster-Shafer inference in Categorical distributions

Description

For a point theta in the simplex, and a vector of counts (N_1,...,N_K), sample for each k, N_k points uniformly in the subsimplex Delta_k(theta), where N_k > 0, and compute the minimum ratio u_n,l / u_n,k for all l in 1,...,K.

Usage

initialize_pts(counts, theta)

Arguments

counts	a vector of K integers representing counts, possibly including zeros
theta	a point in the simplex, represented by a K-vector of non-negative values summing to one

Value

A list with the following entries.

• "pts": a list of K matrices of size N_k x K containing the auxiliary variables, or NA if N_k = 0

• "minratios", a list of K vectors of size K, where minratios[k] has entry ell equal to min_n in I_k u_n,ell / u_n,k which can be used to define 'eta_k,ell'. Equals +Inf if N_k = 0.

Examples

## Not run: 
initialize_pts(c(3,0,2), c(1/3,1/3,1/3))

## End(Not run)

pierrejacob/montecarlodsm documentation built on June 16, 2021, 1:06 p.m.