paper-with-me

홈 › Papers

Insights on Muon from Simple Quadratics

2026-02-12 · Antoine Gonon, Andreea-Alexandra Muşat, Nicolas Boumal arxiv

Muon updates weight matrices along (approximate) polar factors of the gradients and has shown strong empirical performance in large-scale training. Existing attempts at explaining its performance largely focus on single-step comparisons (on quadratic proxies) and worst-case guarantees that treat the inexactness of the polar-factor as a nuisance ``to be argued away''. We show that already on simple strongly convex functions such as $L(W)=\frac12\|W\|_{\text{F}}^2$, these perspectives are insufficient, suggesting that understanding Muon requires going beyond local proxies and pessimistic worst-case bounds. Instead, our analysis exposes two observations that already affect behavior on simple quadratics and are not well captured by prevailing abstractions: (i) approximation error in the polar step can qualitatively alter discrete-time dynamics and improve reachability and finite-time performance -- an effect practitioners exploit to tune Muon, but that existing theory largely treats as a pure accuracy compromise; and (ii) structural properties of the objective affect finite-budget constants beyond the prevailing conditioning-based explanations. Thus, any general theory covering these cases must either incorporate these ingredients explicitly or explain why they are irrelevant in the regimes of interest.

📄 PDF Abstract BibTeX arXiv:2602.11948

Code (0)

등록된 구현이 없습니다.

Similar Papers 제목 키워드 기반

Muon$^p$: Muon with Fractional Spectral Powers

2026-06-11 · Yihe Dong, Will Sawin arxiv

Muon is an increasingly widely used optimizer that replaces a gradient $G=USV^\top$ with its polar factor $UV^\top$, thereby flattening the singular spectrum. However, full flattening discards singular-value information …

Dion2: A Simple Method to Shrink Matrix in Muon

2025-12-01 · Kwangjun Ahn, Noah Amsel, John Langford arxiv

The Muon optimizer enjoys strong empirical performance and theoretical grounding. However, the super-linear cost of its orthonormalization step introduces increasing overhead with scale. To alleviate this cost, several w…

LionMuon: Alternating Spectral and Sign Descent for Efficient Training

2026-05-19 · Arman Bolatov, Artem Riabinin, Nikita Kornilov, Andrey Veprikov 외 arxiv

In large-scale optimization, the cheapness and effectiveness of update steps are the most crucial factors for a successful optimizer. Sign-based optimizers like Lion or Signum produce cheap per-step updates, whereas Muon…

MuonBP: Faster Muon via Block-Periodic Orthogonalization

2025-10-19 · Ahmed Khaled, Kaan Ozkara, Tao Yu, Mingyi Hong 외 arxiv

Gradient orthogonalization is a simple strategy that shows great utility in speeding up gradient descent. The Muon optimizer (Jordan, Jin, et al., 2024) combines gradient orthogonalization with first-order momentum and a…

Practical Efficiency of Muon for Pretraining

2025-05-04 · Essential AI, :, Ishaan Shah, Anthony M. Polloreno 외

We demonstrate that Muon, the simplest instantiation of a second-order optimizer, explicitly expands the Pareto frontier over AdamW on the compute-time tradeoff. We find that Muon is more effective than AdamW in retainin…