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Gluon: Making Muon & Scion Great Again! (Bridging Theory and Practice of LMO-based Optimizers for LLMs)

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arxiv 2505.13416 v1 pith:YBI4VZK4 submitted 2025-05-19 cs.LG math.OCstat.ML

Gluon: Making Muon & Scion Great Again! (Bridging Theory and Practice of LMO-based Optimizers for LLMs)

classification cs.LG math.OCstat.ML
keywords practicallayer-wiselmo-basedmuonpracticepriorscionassumption
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Recent developments in deep learning optimization have brought about radically new algorithms based on the Linear Minimization Oracle (LMO) framework, such as $\sf Muon$ and $\sf Scion$. After over a decade of $\sf Adam$'s dominance, these LMO-based methods are emerging as viable replacements, offering several practical advantages such as improved memory efficiency, better hyperparameter transferability, and most importantly, superior empirical performance on large-scale tasks, including LLM training. However, a significant gap remains between their practical use and our current theoretical understanding: prior analyses (1) overlook the layer-wise LMO application of these optimizers in practice, and (2) rely on an unrealistic smoothness assumption, leading to impractically small stepsizes. To address both, we propose a new LMO-based method called $\sf Gluon$, capturing prior theoretically analyzed methods as special cases, and introduce a new refined generalized smoothness model that captures the layer-wise geometry of neural networks, matches the layer-wise practical implementation of $\sf Muon$ and $\sf Scion$, and leads to convergence guarantees with strong practical predictive power. Unlike prior results, our theoretical stepsizes closely match the fine-tuned values reported by Pethick et al. (2025). Our experiments with NanoGPT and CNN confirm that our assumption holds along the optimization trajectory, ultimately closing the gap between theory and practice.

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Cited by 31 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Local LMO: Constrained Gradient Optimization via a Local Linear Minimization Oracle

    math.OC 2026-05 unverdicted novelty 8.0

    Local LMO is a new projection-free method that achieves the convergence rates of projected gradient descent for constrained optimization by using local linear minimization oracles over small balls.

  2. Sign compression for Muon: SignMuon, MuonSign, and the Limits of Error Feedback

    math.OC 2026-07 conditional novelty 7.0

    Sign-compressing Muon's update to one bit can make it ascend on linear objectives; error feedback works only on the gradient side, yet the divergent sign-after-the-LMO method wins in experiments.

  3. OptMuon: Closed-Loop Orthogonalized Momentum Methods for Stochastic Optimization with Zero-Noise Optimality

    math.OC 2026-06 unverdicted novelty 7.0

    OptMuon combines orthogonalized momentum with closed-loop adaptation to achieve noise-adaptive convergence rates that automatically become near-optimal deterministic first-order rates without retuning when noise vanishes.

  4. LOSCAR-SGD: Local SGD with Communication-Computation Overlap and Delay-Corrected Sparse Model Averaging

    cs.LG 2026-05 unverdicted novelty 7.0

    LOSCAR-SGD combines local updates, sparse model averaging, and communication-computation overlap with a delay-corrected merge rule, providing convergence rates for smooth non-convex objectives under worker heterogeneity.

  5. Ringmaster LMO: Asynchronous Linear Minimization Oracle Momentum Method

    cs.LG 2026-05 unverdicted novelty 7.0

    Ringmaster LMO extends delay-thresholding from ASGD to LMO-based momentum updates, providing convergence guarantees under (L0, L1)-smoothness and time-complexity bounds that recover optimal rates in the Euclidean case.

  6. Symmetry-Compatible Principle for Optimizer Design: Embeddings, LM Heads, SwiGLU MLPs, and MoE Routers

    math.OC 2026-05 conditional novelty 7.0

    Proposes equivariant optimizers matched to the symmetry groups of embeddings, SwiGLU projections and MoE routers, with experiments showing consistent gains over AdamW on language model pre-training.

  7. Phases of Muon: When Muon Eclipses SignSGD

    math.OC 2026-05 unverdicted novelty 7.0

    On power-law covariance least squares problems, SignSVD (Muon) and SignSGD (Adam proxy) show three phases of relative performance depending on data exponent α and target exponent β.

  8. Intrinsic Muon: Spectral Optimization on Riemannian Matrix Manifolds

    cs.LG 2026-05 unverdicted novelty 7.0

    Intrinsic Muon provides closed-form linear maximization oracles on multiple Riemannian matrix manifolds for unitarily invariant norms, with convergence rates depending only on manifold dimension or rank.

  9. Muon with Nesterov Momentum: Heavy-Tailed Noise and (Randomized) Inexact Polar Decomposition

    math.OC 2026-05 unverdicted novelty 7.0

    Muon with Nesterov momentum and inexact polar decomposition achieves optimal convergence rates of O(ε^(-(3α-2)/(α-1))) under heavy-tailed noise for ε-stationary points in non-convex settings.

  10. Hierarchical Semantic Correlation-Aware Masked Autoencoder for Unsupervised Audio-Visual Representation Learning

    cs.MM 2026-04 conditional novelty 6.5

    Localized Muon-style spectral orthogonalization of primary and constraint momentum subspaces (SIFT) reduces objective conflicts and improves constrained LLM steering across four tasks.

  11. Reassessing Muon for Matrix Factorization

    cs.LG 2026-07 conditional novelty 6.0

    Muon's advantage over AdamW is problem-dependent: it loses or ties on plain low-rank factorization and completion but wins on nonnegative matrix factorization.

  12. Convergence Analysis of Muon-type Methods with Inexact LMO in the Degenerate Case

    math.OC 2026-06 unverdicted novelty 6.0

    Convergence rates are derived for Muon-type methods with inexact LMO in the degenerate case under novel assumptions and layer-wise (L^0, L^1)-smoothness for non-convex and star-convex objectives with weight decay.

  13. OptMuon: Closed-Loop Orthogonalized Momentum Methods for Stochastic Optimization with Zero-Noise Optimality

    math.OC 2026-06 unverdicted novelty 6.0

    OptMuon combines orthogonalized momentum with trajectory-dependent AdaGrad-Norm adaptation to obtain expected-stationarity rates of order T^{-1/2} + sigma^{1/2}T^{-1/4} or T^{-1/2} + sigma^{1/3}T^{-1/3} that reduce to...

  14. Symmetry-Compatible Principle for Optimizer Design: Embeddings, LM Heads, SwiGLU MLPs, and MoE Routers

    math.OC 2026-05 unverdicted novelty 6.0

    Proposes equivariant optimizer updates matched to layer symmetries for embeddings, SwiGLU MLPs, and MoE routers, with reported gains in validation loss and training stability on several language model architectures.

  15. Rescaled Asynchronous SGD: Optimal Distributed Optimization under Data and System Heterogeneity

    cs.LG 2026-05 unverdicted novelty 6.0

    Rescaled ASGD recovers convergence to the true global objective by rescaling worker stepsizes proportional to computation times, matching the known time lower bound in the leading term under non-convex smoothness and ...

  16. SUDA-Muon: Structural Design Principles and Boundaries for Fully Decentralized Muon

    math.OC 2026-04 unverdicted novelty 6.0

    SUDA-Muon modularizes decentralized Muon via the SUDA template, proving a topology-separated convergence rate of O((1+σ/√N)K^{-1/4}) in nuclear-norm geometry while establishing that tracking-before-polarization is req...

  17. Preconditioned Norms: A Unified Framework for Steepest Descent, Quasi-Newton and Adaptive Methods

    cs.LG 2025-10 unverdicted novelty 6.0

    Preconditioned matrix norms unify steepest descent, quasi-Newton, and adaptive optimizers, revealing SGD, Adam, Muon, KL-Shampoo, SOAP, and SPlus as special cases and enabling new methods MuAdam and MuAdam-SANIA that ...

  18. DeMuon: A Decentralized Muon for Matrix Optimization over Graphs

    math.OC 2025-10 conditional novelty 6.0

    A decentralized Muon optimizer with gradient tracking reaches a stochastic stationary point at the same iteration complexity as centralized heavy-tailed algorithms.

  19. CMuon: Accelerating and Stabilizing Diffusion Transformer Training via Chunked Momentum Orthogonalization

    cs.AI 2026-08 conditional novelty 5.0

    Chunked Muon, which orthogonalizes fused DiT weight matrices per functional block instead of jointly, reaches FID 1.18 on ImageNet 256 in 200 epochs, about 2× faster than AdamW.

  20. Restart and Adaptive Acceleration in Stochastic Gradient Methods

    math.OC 2026-06 conditional novelty 5.0

    Restart schemes for SGD on KL-satisfying non-smooth weakly convex problems deliver accelerated convergence robust to exponent misspecification, with optimal schedules resembling Polyak steps.

  21. Zero-order Parameter-free Optimization for LMO-based Methods: Novel Approach for Efficient Fine-tuning

    cs.LG 2026-06 unverdicted novelty 5.0

    AdaNAGED combines zeroth-order gradient-free training, automatic parameter adaptation, and LMO-based non-Euclidean geometry with claimed convergence guarantees, demonstrated on OPT-1.3B fine-tuning.

  22. Softsign: Smooth Sign in Your Optimizer For Better Parameter Heterogeneity Handling

    cs.LG 2026-05 unverdicted novelty 5.0

    SoftSignum replaces hard sign with soft-sign in optimizers via temperature control and quantile scheduling, extends to SoftMuon, provides a convergence proof for stochastic non-convex settings, and reports better perf...

  23. Muon in Vision Transformers: Optimizer-Recipe Interactions and Gradient Spectra

    cs.LG 2026-05 conditional novelty 5.0

    Muon optimizer outperforms AdamW in ViT training on two image datasets, with gains that depend on data augmentation strength and are linked to wider singular-value spread in QKV gradients and prevention of late-traini...

  24. MiMuon: Mixed Muon Optimizer with Improved Generalization for Large Models

    cs.LG 2026-05 unverdicted novelty 5.0

    MiMuon is a hybrid optimizer that achieves a generalization error bound of O(1/N) independent of the small singular-value gap that limits the original Muon bound, while retaining the same O(1/T^{1/4}) convergence rate.

  25. Constrained Stochastic Spectral Preconditioning Converges for Nonconvex Objectives

    math.OC 2026-05 unverdicted novelty 5.0

    Proximal stochastic spectral preconditioning converges for nonconvex constrained objectives under heavy-tailed noise, with a variance-reduced version achieving faster rates and a refined analysis of Muon iterations.

  26. Communication-Efficient Gluon in Federated Learning

    cs.LG 2026-04 unverdicted novelty 5.0

    Compressed Gluon variants using unbiased/contraction compressors and SARAH-style variance reduction achieve convergence guarantees and lower communication costs in federated learning under layer-wise smoothness.

  27. Turbo-Muon: Almost-Orthogonal Pre-Conditioning for Fast Muon Updates

    cs.AI 2025-12 conditional novelty 5.0

    AOL column rescaling before Newton-Schulz improves the starting point enough to drop one iteration, making Muon's orthogonalization roughly 2.8x faster at similar final accuracy.

  28. Non-Euclidean SGD for Structured Optimization: Unified Analysis and Improved Rates

    math.OC 2025-11 conditional novelty 5.0

    Non-Euclidean SGD variants (SignSGD, Muon) provably match adaptive optimizers' convergence rates under structured smoothness and noise assumptions.

  29. Why Do We Need Warm-up? A Theoretical Perspective

    cs.LG 2025-10 conditional novelty 5.0

    Under the proposed (H0,H1)-smoothness condition, gradient descent with a warm-up-style adaptive step-size provably converges faster than with any fixed step-size.

  30. Low-rank Orthogonalization for Large-scale Matrix Optimization with Applications to Foundation Model Training

    cs.LG 2025-09 unverdicted novelty 5.0

    Proposes low-rank orthogonalization and derives low-rank Muon and MSGD variants that outperform standard Muon on GPT-2 and LLaMA pretraining while providing iteration complexity bounds.

  31. Reassessing Muon for Matrix Factorization

    cs.LG 2026-07 conditional novelty 4.0

    A controlled benchmark of five matrix-factorization problems shows Muon's advantage over AdamW is problem-dependent: it loses or ties on factorization/completion and wins on NMF; learning-rate tuning reorders the methods.