arXiv Machine Learning

How Many Ranks Does a Token Need? A Noise-Floor Squelch for Rank-One LoRA Experts

arXiv Machine Learning
Oct 3

Score the Update, Not the Token: Descent-Aligned Routing for Combinatorial LoRA Experts

The paper introduces VANE, a new routing strategy for Mixture-of-LoRA-experts that scores experts based on the expected loss reduction of their updates rather than token similarity. By decomposing each expert into a reader and writer, VANE evaluates all reader–writer pairs using a low‑rank compass that predicts the descent direction, enabling efficient top‑k selection with additive gates. Experiments on Llama‑3 models show VANE outperforms twelve PEFT and MoE‑LoRA baselines while using fewer trainable parameters and providing router scores that better reflect expert usefulness.

By Priya Nair, Lukas Brenner, Maya Lindqvist, Daniel Whitmore, Wen-Hsuan Liu, Tom Saliencro, Amara Okonkwo, Rohan Desai
arXiv Machine Learning
Sep 29

New LoRA Skills Should Read but Never Write

The paper introduces READ, a method for composing low‑rank adapters (LoRA) in large language models. By rewriting each adapter into a balanced canonical form and enforcing a one‑directional coupling, READ allows new skills to read but never write into the output subspaces of existing skills, eliminating interference. Experiments on four benchmark suites and two model families show that READ consistently outperforms existing baselines, improving SuperGLUE scores by over twenty points and domain suite scores by more than seven points.

By Zeyan Li, Panqi Yang, Qirong Guo, Shengda Zhuo, SIyuan Qiu, Hu Xu, Chun Li, Jianfeng Xu
arXiv Machine Learning
Oct 21

LoRASpace: A Pool-Wide Shared Substrate for Static and Dynamic Multi-LoRA Composition

arXiv:2610.27444v1 Announce Type: cross Abstract: Low-rank adaptation (LoRA) attaches small low-rank matrices to a frozen backbone, and public repositories host many LoRAs per backbone, each for a di...

By Thamirawaran Sathiyalogeswaran, Navindu De Silva, Chamikara Siriwardane, W. K. Alwis, Jason Mars, Udaya Sampath K. Perera Miriya Thanthrige, Ranga Rodrigo
arXiv Machine Learning
Sep 14

Rank-Efficient LoRA via Joint Tangent-Space Optimization under Isotropic Curvature

The paper introduces ISO-LoRA, an optimizer that improves rank utilization in Low‑Rank Adaptation (LoRA) by coupling factor updates through spectral descent on the induced tangent perturbation in weight space. Experiments on GPT‑2 adaptation show that standard optimizers like AdamW concentrate updates in a few singular directions, whereas ISO-LoRA distributes energy more evenly, leading to higher effective rank and better downstream performance across 0.1B‑7B models. The authors provide theoretical guarantees under a stylized spiked‑gradient model and demonstrate that ISO-LoRA consistently outperforms factor‑wise optimizers, especially at moderate‑to‑large LoRA ranks.

By Zihan Zhu, Zhehang Du, Xuyang Chen, Tim Tsz-Kit Lau, Jiayuan Wu, X. Y. Han, Qi Long, Weijie Su