Injective flows for star-like manifolds

Fuente: arXiv
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Auteurs principaux: Negri, Marcello Massimo, Aellen, Jonathan, Roth, Volker
Format: Preprint
Publié: 2024
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author Negri, Marcello Massimo
Aellen, Jonathan
Roth, Volker
author_facet Negri, Marcello Massimo
Aellen, Jonathan
Roth, Volker
contents Normalizing Flows (NFs) are powerful and efficient models for density estimation. When modeling densities on manifolds, NFs can be generalized to injective flows but the Jacobian determinant becomes computationally prohibitive. Current approaches either consider bounds on the log-likelihood or rely on some approximations of the Jacobian determinant. In contrast, we propose injective flows for star-like manifolds and show that for such manifolds we can compute the Jacobian determinant exactly and efficiently, with the same cost as NFs. This aspect is particularly relevant for variational inference settings, where no samples are available and only some unnormalized target is known. Among many, we showcase the relevance of modeling densities on star-like manifolds in two settings. Firstly, we introduce a novel Objective Bayesian approach for penalized likelihood models by interpreting level-sets of the penalty as star-like manifolds. Secondly, we consider probabilistic mixing models and introduce a general method for variational inference by defining the posterior of mixture weights on the probability simplex.
format Preprint
id arxiv_https___arxiv_org_abs_2406_09116
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Injective flows for star-like manifolds
Negri, Marcello Massimo
Aellen, Jonathan
Roth, Volker
Machine Learning
Normalizing Flows (NFs) are powerful and efficient models for density estimation. When modeling densities on manifolds, NFs can be generalized to injective flows but the Jacobian determinant becomes computationally prohibitive. Current approaches either consider bounds on the log-likelihood or rely on some approximations of the Jacobian determinant. In contrast, we propose injective flows for star-like manifolds and show that for such manifolds we can compute the Jacobian determinant exactly and efficiently, with the same cost as NFs. This aspect is particularly relevant for variational inference settings, where no samples are available and only some unnormalized target is known. Among many, we showcase the relevance of modeling densities on star-like manifolds in two settings. Firstly, we introduce a novel Objective Bayesian approach for penalized likelihood models by interpreting level-sets of the penalty as star-like manifolds. Secondly, we consider probabilistic mixing models and introduce a general method for variational inference by defining the posterior of mixture weights on the probability simplex.
title Injective flows for star-like manifolds
topic Machine Learning
url https://arxiv.org/abs/2406.09116