Repulsive mixtures via the sparsity-inducing partition prior

Fuente: arXiv
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Hauptverfasser: Mozdzen, Alexander, Wertz, Timothy, De Iorio, Maria, Cremaschi, Andrea, Kastner, Gregor, Eriksson, Johan
Format: Preprint
Veröffentlicht: 2025
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author Mozdzen, Alexander
Wertz, Timothy
De Iorio, Maria
Cremaschi, Andrea
Kastner, Gregor
Eriksson, Johan
author_facet Mozdzen, Alexander
Wertz, Timothy
De Iorio, Maria
Cremaschi, Andrea
Kastner, Gregor
Eriksson, Johan
contents We introduce a novel prior distribution for modelling the weights in mixture models based on a generalisation of the Dirichlet distribution, the Selberg Dirichlet distribution. This distribution contains a repulsive term, which naturally penalises values that lie close to each other on the simplex, thus encouraging few dominating clusters. The repulsive behaviour induces additional sparsity on the number of components. We refer to this construction as sparsity-inducing partition (SIP) prior. By highlighting differences with the conventional Dirichlet distribution, we present relevant properties of the SIP prior and demonstrate their implications across a variety of mixture models, including finite mixtures with a fixed or random number of components, as well as repulsive mixtures. We propose an efficient posterior sampling algorithm and validate our model through an extensive simulation study as well as an application to a biomedical dataset describing children's Body Mass Index and eating behaviour.
format Preprint
id arxiv_https___arxiv_org_abs_2509_25860
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Repulsive mixtures via the sparsity-inducing partition prior
Mozdzen, Alexander
Wertz, Timothy
De Iorio, Maria
Cremaschi, Andrea
Kastner, Gregor
Eriksson, Johan
Methodology
We introduce a novel prior distribution for modelling the weights in mixture models based on a generalisation of the Dirichlet distribution, the Selberg Dirichlet distribution. This distribution contains a repulsive term, which naturally penalises values that lie close to each other on the simplex, thus encouraging few dominating clusters. The repulsive behaviour induces additional sparsity on the number of components. We refer to this construction as sparsity-inducing partition (SIP) prior. By highlighting differences with the conventional Dirichlet distribution, we present relevant properties of the SIP prior and demonstrate their implications across a variety of mixture models, including finite mixtures with a fixed or random number of components, as well as repulsive mixtures. We propose an efficient posterior sampling algorithm and validate our model through an extensive simulation study as well as an application to a biomedical dataset describing children's Body Mass Index and eating behaviour.
title Repulsive mixtures via the sparsity-inducing partition prior
topic Methodology
url https://arxiv.org/abs/2509.25860