Saved in:
Bibliographic Details
Main Authors: Ahn, Kwangjun, Xu, Byron, Abreu, Natalie, Fan, Ying, Magakyan, Gagik, Sharma, Pratyusha, Zhan, Zheng, Langford, John
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2504.05295
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866914037368881152
author Ahn, Kwangjun
Xu, Byron
Abreu, Natalie
Fan, Ying
Magakyan, Gagik
Sharma, Pratyusha
Zhan, Zheng
Langford, John
author_facet Ahn, Kwangjun
Xu, Byron
Abreu, Natalie
Fan, Ying
Magakyan, Gagik
Sharma, Pratyusha
Zhan, Zheng
Langford, John
contents Orthonormalized updates accelerate training, improve stability, and enable robust hyperparameter transfer, but existing methods like Muon rely on dense matrix operations that clash with sharded weights in large-scale LLM training, causing high compute and communication cost. We introduce Dion (Distributed Orthonormalization), a scalable and efficient update rule that replaces Newton-Schulz iteration with amortized power iteration on a momentum buffer, avoiding full-matrix reconstruction and integrating cleanly with weight sharding. The rank-fraction parameter with error feedback enables low-rank updates that balance quality with significant cost savings. On language models from 160M to 3B parameters, Dion retains the benefits of orthonormalized updates, while markedly reducing wall-clock time at scale, making it a practical optimizer for next-generation foundation models. Code is available at: https://github.com/microsoft/dion/
format Preprint
id arxiv_https___arxiv_org_abs_2504_05295
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dion: Distributed Orthonormalized Updates
Ahn, Kwangjun
Xu, Byron
Abreu, Natalie
Fan, Ying
Magakyan, Gagik
Sharma, Pratyusha
Zhan, Zheng
Langford, John
Machine Learning
Artificial Intelligence
Optimization and Control
Orthonormalized updates accelerate training, improve stability, and enable robust hyperparameter transfer, but existing methods like Muon rely on dense matrix operations that clash with sharded weights in large-scale LLM training, causing high compute and communication cost. We introduce Dion (Distributed Orthonormalization), a scalable and efficient update rule that replaces Newton-Schulz iteration with amortized power iteration on a momentum buffer, avoiding full-matrix reconstruction and integrating cleanly with weight sharding. The rank-fraction parameter with error feedback enables low-rank updates that balance quality with significant cost savings. On language models from 160M to 3B parameters, Dion retains the benefits of orthonormalized updates, while markedly reducing wall-clock time at scale, making it a practical optimizer for next-generation foundation models. Code is available at: https://github.com/microsoft/dion/
title Dion: Distributed Orthonormalized Updates
topic Machine Learning
Artificial Intelligence
Optimization and Control
url https://arxiv.org/abs/2504.05295