arXiv Machine Learning

Bilevel ZOFO: Efficient LLM Fine-Tuning and Meta-Training

Bilevel-ZOFO is a bilevel optimization framework that combines fast, low‑memory first‑order (FO) parameter‑efficient fine‑tuning (PEFT) in the inner loop with stable, memory‑efficient zeroth‑order (ZO) updates of the full model in the outer loop. This design reduces the variance of ZO gradient estimates, stabilizes training, and mitigates prompt sensitivity while preserving the full model’s capacity. Empirical results show Bilevel-ZOFO achieves 2–4× faster training than existing ZO and FO‑PEFT methods while maintaining similar memory efficiency, and it functions as an efficient meta‑learning algorithm for rapid few‑shot adaptation.

arXiv Machine Learning
Jun 5

Dominant-Layer ZO: A Single Layer Dominates Zeroth-Order Fine-Tuning of LLMs

arXiv:2606. 05516v1 Announce Type: new Abstract: Zeroth-order (ZO) optimization enables memory-efficient fine-tuning of large language models (LLMs) using only forward passes, but it remains unclear how useful adaptation is distributed across layers.

By Wanhao Yu, Ziyan Wang, Zheng Wang, Abeer Matar Almalky, Yihang Zuo, Shuteng Niu, Sen Lin, Adnan Siraj Rakin, Deliang Fan, Li Yang
arXiv Machine Learning
Jul 2

ZO-Act: Efficient Zeroth-Order Fine-Tuning via One-Shot Activation-Informed Low-Rank Subspaces

arXiv:2607. 01125v1 Announce Type: new Abstract: Zeroth-order (ZO) optimization enables fine-tuning large language models when backpropagation is unavailable or memory-prohibitive, but existing methods often perturb full model weights or randomly constructed low-dimensional subspaces, yielding high-variance estimates and limited performance.

By Xun Dong, Yibo Xu, Naigang Wang, Xin Li, Penghang Yin, Zi Yang
arXiv Machine Learning
Jul 14

Memory Savings at What Cost? A Study of Alternatives to Backpropagation

arXiv:2506. 21833v2 Announce Type: replace Abstract: Forward-mode automatic differentiation (FmAD) and zero-order (ZO) optimization are increasingly proposed as memory-efficient, backpropagation-free alternatives for large language model (LLM) fine-tuning, yet their benefits are typically evaluated only against standard backpropagation (BP), omitting memory-efficient variants such as activation checkpointing.

By Kunjal Panchal, Sunav Choudhary, Yuriy Brun, Hui Guan