AMO: Adaptive Muon Orthogonalization

Fuente: arXiv
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Auteurs principaux: Zhuang, Xinlin, Ouyang, Panyi, Li, Yichen, Shi, Jiangming, Chen, Yizhang, Liu, Shuman, Qian, Ying, Liu, Weiyang, Zhang, Haibo, Razzak, Imran
Format: Preprint
Publié: 2026
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author Zhuang, Xinlin
Ouyang, Panyi
Li, Yichen
Shi, Jiangming
Chen, Yizhang
Liu, Shuman
Qian, Ying
Liu, Weiyang
Zhang, Haibo
Razzak, Imran
author_facet Zhuang, Xinlin
Ouyang, Panyi
Li, Yichen
Shi, Jiangming
Chen, Yizhang
Liu, Shuman
Qian, Ying
Liu, Weiyang
Zhang, Haibo
Razzak, Imran
contents Muon has recently emerged as a competitive alternative to AdamW for large-scale pre-training, with orthogonalization via Newton-Schulz (NS) iterations as its core operation. Existing Muon variants apply a uniform NS schedule to all parameter matrices, overlooking possible differences in orthogonalization difficulty and its impact on performance. Through a systematic empirical study, we show that this per-matrix heterogeneity is pervasive and largely determined by matrix geometry, which evolves dynamically across operator types, training stages, and network depths. As a result, uniform NS schedules can lead to uneven orthogonalization quality across the model. Motivated by these findings, we propose Adaptive Muon Orthogonalization (AMO), an observe-then-commit method that measures weight geometry by operator type early in training and then uses these signals to allocate the NS budget for the remainder of training. AMO delivers consistent improvements over uniform-schedule Muon across standard, prolonged, and continual pre-training, surpassing the strongest baseline by +0.76 on Llama3.1-1.4B and +0.51 on Qwen3-1.7B in average downstream performance of 12 evaluation tasks.
format Preprint
id arxiv_https___arxiv_org_abs_2605_17806
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle AMO: Adaptive Muon Orthogonalization
Zhuang, Xinlin
Ouyang, Panyi
Li, Yichen
Shi, Jiangming
Chen, Yizhang
Liu, Shuman
Qian, Ying
Liu, Weiyang
Zhang, Haibo
Razzak, Imran
Machine Learning
Muon has recently emerged as a competitive alternative to AdamW for large-scale pre-training, with orthogonalization via Newton-Schulz (NS) iterations as its core operation. Existing Muon variants apply a uniform NS schedule to all parameter matrices, overlooking possible differences in orthogonalization difficulty and its impact on performance. Through a systematic empirical study, we show that this per-matrix heterogeneity is pervasive and largely determined by matrix geometry, which evolves dynamically across operator types, training stages, and network depths. As a result, uniform NS schedules can lead to uneven orthogonalization quality across the model. Motivated by these findings, we propose Adaptive Muon Orthogonalization (AMO), an observe-then-commit method that measures weight geometry by operator type early in training and then uses these signals to allocate the NS budget for the remainder of training. AMO delivers consistent improvements over uniform-schedule Muon across standard, prolonged, and continual pre-training, surpassing the strongest baseline by +0.76 on Llama3.1-1.4B and +0.51 on Qwen3-1.7B in average downstream performance of 12 evaluation tasks.
title AMO: Adaptive Muon Orthogonalization
topic Machine Learning
url https://arxiv.org/abs/2605.17806