arXiv AI

Provable Benefit of SignGD: A Minimal Model Under Heavy-Tailed Class Imbalance

arXiv Machine Learning
Aug 27

StoSignSGD: Unbiased Structural Stochasticity Fixes SignSGD for Training Large Language Models

StoSignSGD is a new sign‑based optimization algorithm that injects structural stochasticity into the sign operator, ensuring unbiased updates. It resolves the divergence issues of traditional SignSGD on non‑smooth objectives, achieving optimal convergence rates in convex settings and improved complexity bounds in non‑convex, non‑smooth problems. Empirical results show that StoSignSGD is stable and efficient across large language model training, outperforming AdamW and SignSGD in low‑precision regimes (FP8 and FP4) and delivering speedups and accuracy gains on models ranging from OLMo2‑370M to 7B LLMs.

By Dingzhi Yu, Rui Pan, Yuxing Liu, Difan Zou, Tong Zhang
arXiv Machine Learning
Aug 18

Language models suffer from a curse of ambiguity

arXiv:2608. 15448v1 Announce Type: cross Abstract: Large language models increasingly rely on sampling as a driver of their own improvement, making the fidelity of their learned distributions more critical than ever.

By Nicolas Zucchet, Hyun Dong Lee, Scott Linderman
arXiv Machine Learning
Sep 11

Rebalancing Token Importance in Language Models with TF-IDF Weighted Cross-Entropy Loss

The paper proposes an information-weighted cross‑entropy loss that rescales token contributions using TF‑IDF statistics, thereby emphasizing semantically informative tokens and down‑weighting ubiquitous ones. Experiments on five decoder‑only language models (1.1B–13B parameters) show consistent reductions in memorized substring length while maintaining perplexity and downstream performance. The method is architecture‑agnostic, adds less than 3% computational overhead, and can be integrated into existing training pipelines.

By Zhijian Li, Stefan Larson, Kevin Leach