Deep Linear Discriminant Analysis Revisited

Fuente: arXiv
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Auteurs principaux: Tezekbayev, Maxat, Takhanov, Rustem, Bolatov, Arman, Assylbekov, Zhenisbek
Format: Preprint
Publié: 2026
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author Tezekbayev, Maxat
Takhanov, Rustem
Bolatov, Arman
Assylbekov, Zhenisbek
author_facet Tezekbayev, Maxat
Takhanov, Rustem
Bolatov, Arman
Assylbekov, Zhenisbek
contents We show that for unconstrained Deep Linear Discriminant Analysis (LDA) classifiers, maximum-likelihood training admits pathological solutions in which class means drift together, covariances collapse, and the learned representation becomes almost non-discriminative. Conversely, cross-entropy training yields excellent accuracy but decouples the head from the underlying generative model, leading to highly inconsistent parameter estimates. To reconcile generative structure with discriminative performance, we introduce the \emph{Discriminative Negative Log-Likelihood} (DNLL) loss, which augments the LDA log-likelihood with a simple penalty on the mixture density. DNLL can be interpreted as standard LDA NLL plus a term that explicitly discourages regions where several classes are simultaneously likely. Deep LDA trained with DNLL produces clean, well-separated latent spaces, matches the test accuracy of softmax classifiers on synthetic data and standard image benchmarks, and yields substantially better calibrated predictive probabilities, restoring a coherent probabilistic interpretation to deep discriminant models.
format Preprint
id arxiv_https___arxiv_org_abs_2601_01619
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Deep Linear Discriminant Analysis Revisited
Tezekbayev, Maxat
Takhanov, Rustem
Bolatov, Arman
Assylbekov, Zhenisbek
Machine Learning
We show that for unconstrained Deep Linear Discriminant Analysis (LDA) classifiers, maximum-likelihood training admits pathological solutions in which class means drift together, covariances collapse, and the learned representation becomes almost non-discriminative. Conversely, cross-entropy training yields excellent accuracy but decouples the head from the underlying generative model, leading to highly inconsistent parameter estimates. To reconcile generative structure with discriminative performance, we introduce the \emph{Discriminative Negative Log-Likelihood} (DNLL) loss, which augments the LDA log-likelihood with a simple penalty on the mixture density. DNLL can be interpreted as standard LDA NLL plus a term that explicitly discourages regions where several classes are simultaneously likely. Deep LDA trained with DNLL produces clean, well-separated latent spaces, matches the test accuracy of softmax classifiers on synthetic data and standard image benchmarks, and yields substantially better calibrated predictive probabilities, restoring a coherent probabilistic interpretation to deep discriminant models.
title Deep Linear Discriminant Analysis Revisited
topic Machine Learning
url https://arxiv.org/abs/2601.01619