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Main Authors: Huang, Wei-Ping, Yu, Chee-En, Lin, Guan-Ting, Lee, Hung-yi
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2605.08186
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author Huang, Wei-Ping
Yu, Chee-En
Lin, Guan-Ting
Lee, Hung-yi
author_facet Huang, Wei-Ping
Yu, Chee-En
Lin, Guan-Ting
Lee, Hung-yi
contents Test-Time Adaptation (TTA) via entropy minimization (EM) has proven effective for classification tasks, yet its application to generative autoregressive models remains theoretically fragmented. Existing approaches typically rely on distinct heuristics, such as teacher forcing with pseudo labels or policy-gradient-based reinforcement learning, without a unified mathematical foundation. In this work, we resolve this discrepancy by deriving a rigorous formulation of EM tailored to autoregressive models. We show that the exact objective naturally decomposes into a token-level policy gradient loss and a token-level entropy loss, and we reinterpret prior methods as partial realizations of this unified formulation. Using Whisper ASR as a testbed, we demonstrate that our approach consistently improves performance across more than 20 diverse domains, including acoustic noise, accents, and multilingual settings.
format Preprint
id arxiv_https___arxiv_org_abs_2605_08186
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Rethinking Entropy Minimization in Test-Time Adaptation for Autoregressive Models
Huang, Wei-Ping
Yu, Chee-En
Lin, Guan-Ting
Lee, Hung-yi
Audio and Speech Processing
Artificial Intelligence
Machine Learning
Test-Time Adaptation (TTA) via entropy minimization (EM) has proven effective for classification tasks, yet its application to generative autoregressive models remains theoretically fragmented. Existing approaches typically rely on distinct heuristics, such as teacher forcing with pseudo labels or policy-gradient-based reinforcement learning, without a unified mathematical foundation. In this work, we resolve this discrepancy by deriving a rigorous formulation of EM tailored to autoregressive models. We show that the exact objective naturally decomposes into a token-level policy gradient loss and a token-level entropy loss, and we reinterpret prior methods as partial realizations of this unified formulation. Using Whisper ASR as a testbed, we demonstrate that our approach consistently improves performance across more than 20 diverse domains, including acoustic noise, accents, and multilingual settings.
title Rethinking Entropy Minimization in Test-Time Adaptation for Autoregressive Models
topic Audio and Speech Processing
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2605.08186