Accelerating LLM Pre-Training through Flat-Direction Dynamics Enhancement

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Zhu, Shuchen, Hu, Rizhen, Wang, Mingze, Sun, Mou, Wang, Xue, Yuan, Kun, Wen, Zaiwen
Format: Preprint
Published: 2026
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866918357284945920
author Zhu, Shuchen
Hu, Rizhen
Wang, Mingze
Sun, Mou
Wang, Xue
Yuan, Kun
Wen, Zaiwen
author_facet Zhu, Shuchen
Hu, Rizhen
Wang, Mingze
Sun, Mou
Wang, Xue
Yuan, Kun
Wen, Zaiwen
contents Pre-training Large Language Models requires immense computational resources, making optimizer efficiency essential. The optimization landscape is highly anisotropic, with loss reduction driven predominantly by progress along flat directions. While matrix-based optimizers such as Muon and SOAP leverage fine-grained curvature information to outperform AdamW, their updates tend toward isotropy -- relatively conservative along flat directions yet potentially aggressive along sharp ones. To address this limitation, we first establish a unified Riemannian Ordinary Differential Equation (ODE) framework that elucidates how common adaptive algorithms operate synergistically: the preconditioner induces a Riemannian geometry that mitigates ill-conditioning, while momentum serves as a Riemannian damping term that promotes convergence. Guided by these insights, we propose LITE, a generalized acceleration strategy that enhances training dynamics by applying larger Hessian damping coefficients and learning rates along flat trajectories. Extensive experiments demonstrate that LITE significantly accelerates both Muon and SOAP across diverse architectures (Dense, MoE), parameter scales (130M--1.3B), datasets (C4, Pile), and learning-rate schedules (cosine, warmup-stable-decay). Theoretical analysis confirms that LITE facilitates faster convergence along flat directions in anisotropic landscapes, providing a principled approach to efficient LLM pre-training. The code is available at https://github.com/SHUCHENZHU/LITE.
format Preprint
id arxiv_https___arxiv_org_abs_2602_22681
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Accelerating LLM Pre-Training through Flat-Direction Dynamics Enhancement
Zhu, Shuchen
Hu, Rizhen
Wang, Mingze
Sun, Mou
Wang, Xue
Yuan, Kun
Wen, Zaiwen
Machine Learning
Pre-training Large Language Models requires immense computational resources, making optimizer efficiency essential. The optimization landscape is highly anisotropic, with loss reduction driven predominantly by progress along flat directions. While matrix-based optimizers such as Muon and SOAP leverage fine-grained curvature information to outperform AdamW, their updates tend toward isotropy -- relatively conservative along flat directions yet potentially aggressive along sharp ones. To address this limitation, we first establish a unified Riemannian Ordinary Differential Equation (ODE) framework that elucidates how common adaptive algorithms operate synergistically: the preconditioner induces a Riemannian geometry that mitigates ill-conditioning, while momentum serves as a Riemannian damping term that promotes convergence. Guided by these insights, we propose LITE, a generalized acceleration strategy that enhances training dynamics by applying larger Hessian damping coefficients and learning rates along flat trajectories. Extensive experiments demonstrate that LITE significantly accelerates both Muon and SOAP across diverse architectures (Dense, MoE), parameter scales (130M--1.3B), datasets (C4, Pile), and learning-rate schedules (cosine, warmup-stable-decay). Theoretical analysis confirms that LITE facilitates faster convergence along flat directions in anisotropic landscapes, providing a principled approach to efficient LLM pre-training. The code is available at https://github.com/SHUCHENZHU/LITE.
title Accelerating LLM Pre-Training through Flat-Direction Dynamics Enhancement
topic Machine Learning
url https://arxiv.org/abs/2602.22681