Parameter-efficient fine-tuning (PEFT) is a standard way to adapt multimodal large language models, yet extremely low-rank settings -- especially rank-1 LoRA -- are often unstable. We show that this instability is not solely due to limited capacity: in the rank-1 regime, optimization is highly sensitive to the update direction. Concretely, pretrained vision and text features form mismatched anisotropic regions, yielding a dominant "gap" direction that acts like a translation component and disproportionately steers early gradients under rank-1 constraints. Analyzing pretrained representations, we identify a modality-gap axis that dominates early gradient flow, while a random rank-1 initialization is unlikely to align with it, leading to weak gradients and training collapse. We propose Gap-Init, a geometry-aware initialization that aligns the rank-1 LoRA direction with an estimated modality-gap vector from a small calibration set, while keeping the initial LoRA update zero. Across multiple vision-language tasks and backbones, Gap-Init consistently stabilizes rank-1 training and can match or outperform strong rank-8 baselines. Our results suggest that at the extreme low-rank limit, initial alignment can matter as much as rank itself.
Learning in the Fisher Subspace: A Guided Initialization for LoRA Fine-Tuning
Department of Computer Science(计算机科学系);Information Engineering, National Cheng Kung University(信息工程系,国立成功大学);Department of Artificial Intelligence, Chang Gung University(人工智能系,长庚大学);Department of Computer Science, National Tsing Hua University(计算机科学系,国立清华大学)
Improving Fast Adversarial Training with Prior-Guided Knowledge
Institute of Information Engineering, Chinese Academy of Sciences(中国科学院信息工程研究所);University of Chinese Academy of Sciences(中国科学院大学);Tencent Inc.(腾讯公司);Beihang University(北京航空航天大学);The Chinese University of Hong Kong, Shenzhen(香港中文大学(深圳));Shenzhen Research Institute of Big Data(深圳大数据研究院);Sun Yat-sen University(中山大学)
LLM-Guided Initialization for Accelerated Hybrid Quantum-Classical Medical Image Classification
Faculty of Computing Universiti Teknologi Malaysia Johor Bahru, Malaysia Remote Student based in Jakarta, Indonesia;Informatics Department Faculty of Science;Faculty of Computing Universiti Teknologi Malaysia Johor Bahru, Malaysia
Teacher-Student Gaps Are Not Enough: Outcome-Guided On-Policy Distillation for Multi-Turn Autonomous Agents
Qwen Large Model Application Team, Alibaba(阿里巴巴通义千问大模型应用团队);Peking University(北京大学);University of Chinese Academy of Sciences(中国科学院大学);Shanghai Jiao Tong University(上海交通大学)
Learning High-Degree Parities: The Crucial Role of the Initialization
Ecole Polytechnique Fédérale de Lausanne (EPFL)(洛桑联邦理工学院);Massachusetts Institute of Technology (MIT)(麻省理工学院);Inria Paris(法国国家信息与自动化研究所巴黎分部);PSL University(巴黎文理研究大学);African Institute for Mathematical Sciences (AIMS)(非洲数学科学研究院)
Alignment-Aware Model Adaptation via Feedback-Guided Optimization
Department of Computer Science, University of British Columbia, Location, Canada(不列颠哥伦比亚大学计算机科学系);Vector Institute of AI, Toronto, Canada(人工智能向量研究所);Stony Brook University, New York, USA(石溪大学)
Enhancing Pretrained Model-based Continual Representation Learning via Guided Random Projection
Wuhan University(武汉大学);Shanghai Innovation Institute(上海创新研究院);Shanghai Jiao Tong University(上海交通大学);Tsinghua University(清华大学);University of Science and Technology of China(中国科学技术大学);China University of Mining and Technology(中国矿业大学)