arXiv Machine Learning

Muon on the Stiefel Manifold Admits an Exact Closed-Form Update

arXiv:2608. 06218v1 Announce Type: cross Abstract: We study Muon, a recently proposed matrix-aware optimization method, in the context of the Stiefel manifold.

arXiv Machine Learning
Jul 2

Optimization on the Oblique Manifold for Sparse Simplex Constraints via Multiplicative Updates

arXiv:2503. 24075v4 Announce Type: replace-cross Abstract: Low-rank optimization problems with sparse simplex constraints involve variables that must satisfy nonnegativity, sparsity, and sum-to-1 conditions, making their optimization particularly challenging due to the interplay between low-rank structures and constraints.

By Flavia Esposito, Andersen Ang
arXiv AI
Sep 24

Riemannian Structure and Optimization for a Class of Low-Parametric Orthogonal Matrices

The paper studies matrices built from block‑diagonal factors interleaved with fixed permutations, a structured family useful in deep learning for balancing expressivity and efficiency. By applying Riemannian geometry, the authors determine when this class forms a smooth manifold and develop Riemannian tools for the orthogonal two‑factor case. They propose efficient algorithms that use automatic differentiation, allow parameter sharing, and avoid dense matrix construction, testing them on matrix approximation and fine‑tuning large language models, while also exploring properties of factorizations with more factors.

By Ali Aliev, Maxim Rakhuba
arXiv Machine Learning
Jun 2

Riemannian Optimization for Hadamard Products of Low-Rank Matrices

arXiv:2606. 01216v1 Announce Type: new Abstract: The elementwise Hadamard product of two low-rank matrices provides a parameter-efficient model for data with multiplicative structure, but its modeling is challenging due to the presence of additional symmetries under coupled row/column scalings between the two factors.

By Pratik Jawanpuria, Ankish Chandresh, Bamdev Mishra
arXiv Machine Learning
Jun 25

Tensorion: A Tensor-Aware Generalization of the Muon Optimizer

arXiv:2606. 25975v1 Announce Type: new Abstract: Common first-order optimizers, such as Adam, implicitly treat each parameter block as an unstructured vector, which disregards the multilinear weight structure present in many modern machine learning models.

By Vladimir Bogachev, Vladimir Aletov, Alexander Molozhavenko, Sergei Kudriashov, Maxim Rakhuba