Bayesian Multinomial Logistic Regression for Numerous Categories

Fuente: arXiv
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Auteurs principaux: Fisher, Jared D., McEvoy, Kyle R.
Format: Preprint
Publié: 2022
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author Fisher, Jared D.
McEvoy, Kyle R.
author_facet Fisher, Jared D.
McEvoy, Kyle R.
contents Bayesian multinomial logistic regression provides a principled, interpretable approach to multiclass classification, but posterior sampling becomes increasingly expensive as the model dimension grows. Prior work has studied scalability in the number of subjects and covariates; in contrast, this paper focuses on how computation changes as the number of outcome categories increases. To improve scalability in settings with numerous categories, we adapt a gamma-augmentation strategy to decouple category-specific coefficient updates, so that each category's coefficients can be updated conditional on a single auxiliary variable per subject, rather than on the full set of other categories' coefficients. Because the resulting coefficient conditionals are non-conjugate, we couple this augmentation with either adaptive Metropolis-Hastings or elliptical slice sampling. Through simulation and a real-data example, we compare effective sample size and effective sampling rate across several standard competitors. We find that the best-performing sampler depends on the dimension and imbalance regime, and that the proposed augmentation provides substantial speedups in scenarios with numerous categories.
format Preprint
id arxiv_https___arxiv_org_abs_2208_14537
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Bayesian Multinomial Logistic Regression for Numerous Categories
Fisher, Jared D.
McEvoy, Kyle R.
Computation
Methodology
Bayesian multinomial logistic regression provides a principled, interpretable approach to multiclass classification, but posterior sampling becomes increasingly expensive as the model dimension grows. Prior work has studied scalability in the number of subjects and covariates; in contrast, this paper focuses on how computation changes as the number of outcome categories increases. To improve scalability in settings with numerous categories, we adapt a gamma-augmentation strategy to decouple category-specific coefficient updates, so that each category's coefficients can be updated conditional on a single auxiliary variable per subject, rather than on the full set of other categories' coefficients. Because the resulting coefficient conditionals are non-conjugate, we couple this augmentation with either adaptive Metropolis-Hastings or elliptical slice sampling. Through simulation and a real-data example, we compare effective sample size and effective sampling rate across several standard competitors. We find that the best-performing sampler depends on the dimension and imbalance regime, and that the proposed augmentation provides substantial speedups in scenarios with numerous categories.
title Bayesian Multinomial Logistic Regression for Numerous Categories
topic Computation
Methodology
url https://arxiv.org/abs/2208.14537