On the Posterior Computation Under the Dirichlet-Laplace Prior

Fuente: arXiv
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Auteurs principaux: Onorati, Paolo, Dunson, David B., Canale, Antonio
Format: Preprint
Publié: 2025
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author Onorati, Paolo
Dunson, David B.
Canale, Antonio
author_facet Onorati, Paolo
Dunson, David B.
Canale, Antonio
contents Modern applications routinely collect high-dimensional data, leading to statistical models having more parameters than there are samples available. A common solution is to impose sparsity in parameter estimation, often using penalized optimization methods. Bayesian approaches provide a probabilistic framework to formally quantify uncertainty through shrinkage priors. Among these, the Dirichlet-Laplace prior has attained recognition for its theoretical guarantees and wide applicability. This article identifies a critical yet overlooked issue in the implementation of Gibbs sampling algorithms for such priors. We demonstrate that ambiguities in the presentation of key algorithmic steps, while mathematically coherent, have led to widespread implementation inaccuracies that fail to target the intended posterior distribution -- a target endowed with rigorous asymptotic guarantees. Using the normal-means problem and high-dimensional linear regressions as canonical examples, we clarify these implementation pitfalls and their practical consequences and propose corrected and more efficient sampling procedures.
format Preprint
id arxiv_https___arxiv_org_abs_2507_05214
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the Posterior Computation Under the Dirichlet-Laplace Prior
Onorati, Paolo
Dunson, David B.
Canale, Antonio
Methodology
Modern applications routinely collect high-dimensional data, leading to statistical models having more parameters than there are samples available. A common solution is to impose sparsity in parameter estimation, often using penalized optimization methods. Bayesian approaches provide a probabilistic framework to formally quantify uncertainty through shrinkage priors. Among these, the Dirichlet-Laplace prior has attained recognition for its theoretical guarantees and wide applicability. This article identifies a critical yet overlooked issue in the implementation of Gibbs sampling algorithms for such priors. We demonstrate that ambiguities in the presentation of key algorithmic steps, while mathematically coherent, have led to widespread implementation inaccuracies that fail to target the intended posterior distribution -- a target endowed with rigorous asymptotic guarantees. Using the normal-means problem and high-dimensional linear regressions as canonical examples, we clarify these implementation pitfalls and their practical consequences and propose corrected and more efficient sampling procedures.
title On the Posterior Computation Under the Dirichlet-Laplace Prior
topic Methodology
url https://arxiv.org/abs/2507.05214