arXiv Machine Learning

Weight Clustering Reveals the Importance of Relative Rank in Large Language Models

The study demonstrates that large language models can be compressed by clustering weight matrices into only 16–64 shared values without retraining, preserving strong accuracy. Fine‑tuning the cluster centroids recovers most of the remaining accuracy loss. Analysis reveals that maintaining the relative rank of weights and their overall variance is crucial for performance, while early layers and spatial geometry of cluster assignments also play significant roles.

arXiv Machine Learning
Aug 31

Negligible in Size, Significant in Effect: On Scale Vectors in Large Language Models

The paper investigates the often-overlooked scale vectors in large language models, showing that despite their tiny size they are crucial for pre‑training performance. The authors provide theoretical insights that scale vectors mainly aid optimization rather than expressivity, and they analyze how weight decay affects different normalization layers. Building on these findings, they propose lightweight improvements—branch‑specific heterogeneity, better placement, and magnitude‑direction reparameterization—that consistently reduce loss across a range of model sizes and training settings.

By Mingze Wang, Shuchen Zhu, Yuxin Fang, Binghui Li, Kai Shen, Shu Zhong
arXiv Computation and Language
Sep 21

Souper-Model: How Simple Arithmetic Unlocks State-of-the-Art LLM Performance

arXiv:2511.13254v2 Announce Type: replace Abstract: Large Language Models (LLMs) have displayed remarkable capabilities across diverse domains, but their training remains resource- and time-intensive...

By Shalini Maiti, Amar Budhiraja, Bhavul Gauri, Gaurav Chaurasia, Anton Protopopov, Alexis Audran-Reiss, Michael Slater, Despoina Magka, Tatiana Shavrina, Roberta Raileanu, Yoram Bachrach
arXiv Machine Learning
Sep 4

MSign: An Optimizer Preventing Training Instability in Large Language Models via Stable Rank Restoration

The paper introduces MSign, an optimizer designed to prevent training instability in large language models by restoring the stable rank of weight matrices. It identifies two precursors to gradient explosions—rapid stable rank decline and increased Jacobian alignment—and proves that these jointly cause exponential gradient growth. Experiments on models ranging from 5 M to 3 B parameters show that MSign stops training failures while adding less than 7.0% computational overhead.

By Lianhai Ren, Yucheng Ding, Xiao Liu, Peng Cheng, Yeyun Gong
arXiv AI
Jul 21

Sparsity-Aware Low-Rank Representation for Efficient Fine-Tuning of Large Language Models

arXiv:2601. 16991v3 Announce Type: replace-cross Abstract: Adapting large pre-trained language models to downstream tasks often entails fine-tuning millions of parameters or deploying costly dense weight updates, which hinders their use in resource-constrained environments.

By Longteng Zhang, Sen Wu, Shuai Hou, Zhengyu Qing, Zhuo Zheng, Danning Ke, Qihong Lin, Qiang Wang, Shaohuai Shi, Xiaowen Chu
arXiv Machine Learning
Aug 27

When Pruning Meets Interpretability: Preserving Sparse Autoencoder Robustness in LLMs

Sparse autoencoders (SAEs) are commonly used to interpret large language models, but their reliability after pruning is unclear. This study shows that pruning’s effect on an SAE is governed by perturbation energy, a covariance-weighted norm, and that magnitude pruning distorts the representation space by ignoring activation geometry. Activation-aware pruning methods such as Wanda and SparseGPT better preserve SAE behavior, and the authors find that middle layers are especially vulnerable, leading them to propose a layer‑wise sparsity allocation that reduces perplexity for a given sparsity level.

By Suchit Gupte, Xueru Zhang, Mohammad Mahdi Khalili
arXiv Machine Learning
Jul 17

Stabilizing Native Low-Rank LLM Pretraining

arXiv:2602. 12429v2 Announce Type: replace Abstract: Foundation models have achieved remarkable success, yet their growing parameter counts pose significant computational and memory challenges.

By Paul Janson, Edouard Oyallon, Eugene Belilovsky
arXiv Computation and Language
Oct 1

Learning Functional Subspaces for Neural Network Compression

arXiv:2609.40127v1 Announce Type: cross Abstract: Modern transformers pair impressive capabilities with substantial memory and compute demands. Low-rank weight factorization reduces both while keepin...

By Massimo Bini, Anders Christensen, Stephan Alaniz, Judah Goldfeder, Ole Winther, Yann LeCun, Ravid Shwartz-Ziv, Zeynep Akata
arXiv AI
Jul 7

Spectral Signatures of Large Language Models

arXiv:2607. 03377v1 Announce Type: cross Abstract: The rapidly growing repository of publicly available large language models (LLMs) presents significant challenges for systematic management and quantification at scale, such as model lineage tracing, licensing, and evaluation.

By Zhuoying Zhang, Ishan V. Prasad, Yuanzhe Hu, Zihang Liu, Hengrui Luo, Pu Ren, Yaoqing Yang