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arXiv 2512.02441cs.CVcs.LG

以基为导向的低秩迁移:少样本和测试时适应

Basis-Oriented Low-rank Transfer for Few-Shot and Test-Time Adaptation

TelePIX;Arizona State University(亚利桑那州立大学)

Junghwan Park, Woojin Cho, Junhyuk Heo, Darongsae Kwon, Kookjin Lee

AI总结:

BOLT通过提取正交谱基实现低秩迁移,为少样本和测试时适应提供高效且稳定的参数微调方法。

摘要:

在有限的数据和计算预算下适应大型预训练模型以应对未见过的任务仍然具有挑战性。元学习方法明确地学习好的初始设置,但它们需要在许多任务上进行额外的元训练阶段,导致高训练成本,并且可能不稳定。同时,任务特定的预训练模型数量持续增长,但如何将它们转移到新任务并最小化额外训练仍相对未被探索。我们提出了BOLT(以基为导向的低秩迁移),一个框架,通过提取一个正交的任务导向谱基并在此子空间内进行适应,而不是通过合并权重。在离线阶段,BOLT从多个任务向量中收集主导的奇异方向,并按层正交化以形成可重用的基。在在线阶段,我们冻结这些基,并仅训练每个层的一小部分对角系数以适应新任务,从而得到一个受秩控制的更新,具有非常少的可训练参数。这种设计提供了(i)一个强大的、无需训练的初始设置用于未见过的任务,通过池化源任务系数获得,同时利用共享的正交基进行轻量级重缩放,以及(ii)一种参数高效的微调(PEFT)路径,在我们的实验中,与常见的PEFT基线以及代表性的元学习初始设置相比,实现了稳健的性能。我们的结果表明,将适应限制在任务导向的正交子空间中为未见过的任务转移提供了一种有效的替代方案。

英文摘要:

Adapting large pre-trained models to unseen tasks under tight data and compute budgets remains challenging. Meta-learning approaches explicitly learn good initializations, but they require an additional meta-training phase over many tasks, incur high training cost, and can be unstable. At the same time, the number of task-specific pre-trained models continues to grow, yet the question of how to transfer them to new tasks with minimal additional training remains relatively underexplored. We propose BOLT (Basis-Oriented Low-rank Transfer), a framework that reuses existing fine-tuned models not by merging weights, but instead by extracting an orthogonal, task-informed spectral basis and adapting within that subspace. In the offline phase, BOLT collects dominant singular directions from multiple task vectors and orthogonalizes them per layer to form reusable bases. In the online phase, we freeze these bases and train only a small set of diagonal coefficients per layer for the new task, yielding a rank-controlled update with very few trainable parameters. This design provides (i) a strong, training-free initialization for unseen tasks, obtained by pooling source-task coefficients, along with a lightweight rescaling step while leveraging the shared orthogonal bases, and (ii) a parameter-efficient fine-tuning (PEFT) path that, in our experiments, achieves robust performance compared to common PEFT baselines as well as a representative meta-learned initialization. Our results show that constraining adaptation to a task-informed orthogonal subspace provides an effective alternative for unseen-task transfer.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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