Stabilizing Native Low-Rank LLM Pretraining

Fuente: arXiv
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Auteurs principaux: Janson, Paul, Oyallon, Edouard, Belilovsky, Eugene
Format: Preprint
Publié: 2026
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author Janson, Paul
Oyallon, Edouard
Belilovsky, Eugene
author_facet Janson, Paul
Oyallon, Edouard
Belilovsky, Eugene
contents Foundation models have achieved remarkable success, yet their growing parameter counts pose significant computational and memory challenges. Low-rank factorization offers a promising route to reduce training and inference costs, but the community lacks a stable recipe for training models from scratch using exclusively low-rank weights while matching the performance of the dense model. We demonstrate that Large Language Models (LLMs) can be trained from scratch using exclusively low-rank factorized weights for all non-embedding matrices without auxiliary "full-rank" guidance required by prior methods. While native low-rank training often suffers from instability and loss spikes, we identify uncontrolled growth in the spectral norm (largest singular value) of the weight matrix update as the dominant factor. To address this, we introduce Spectron: Spectral renormalization with orthogonalization, which dynamically bounds the resultant weight updates based on the current spectral norms of the factors. Our method enables stable, end-to-end factorized training with negligible overhead. Finally, we establish compute-optimal scaling laws for natively low-rank transformers, demonstrating predictable power-law behavior and improved inference efficiency relative to dense models.
format Preprint
id arxiv_https___arxiv_org_abs_2602_12429
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Stabilizing Native Low-Rank LLM Pretraining
Janson, Paul
Oyallon, Edouard
Belilovsky, Eugene
Machine Learning
Foundation models have achieved remarkable success, yet their growing parameter counts pose significant computational and memory challenges. Low-rank factorization offers a promising route to reduce training and inference costs, but the community lacks a stable recipe for training models from scratch using exclusively low-rank weights while matching the performance of the dense model. We demonstrate that Large Language Models (LLMs) can be trained from scratch using exclusively low-rank factorized weights for all non-embedding matrices without auxiliary "full-rank" guidance required by prior methods. While native low-rank training often suffers from instability and loss spikes, we identify uncontrolled growth in the spectral norm (largest singular value) of the weight matrix update as the dominant factor. To address this, we introduce Spectron: Spectral renormalization with orthogonalization, which dynamically bounds the resultant weight updates based on the current spectral norms of the factors. Our method enables stable, end-to-end factorized training with negligible overhead. Finally, we establish compute-optimal scaling laws for natively low-rank transformers, demonstrating predictable power-law behavior and improved inference efficiency relative to dense models.
title Stabilizing Native Low-Rank LLM Pretraining
topic Machine Learning
url https://arxiv.org/abs/2602.12429