Delta激活:微调大型語言模型的一種表徵方式
Delta Activations: A Representation for Finetuned Large Language Models
September 4, 2025
作者: Zhiqiu Xu, Amish Sethi, Mayur Naik, Ser-Nam Lim
cs.AI
摘要
強大的開源大型語言模型(LLMs)的成功,使得社群能夠創建大量針對特定任務和領域進行後訓練的模型。然而,由於不一致的元數據和非結構化的儲存庫,導航和理解這些模型仍然具有挑戰性。我們引入了Delta Activations方法,該方法通過測量微調模型相對於基礎模型內部激活的變化,將微調模型表示為向量嵌入。這種表示方式允許按領域和任務進行有效的聚類,從而揭示模型景觀中的結構。Delta Activations還展示了理想的特性:它在不同的微調設置下具有魯棒性,並且在微調數據集混合時表現出可加性。此外,我們展示了Delta Activations可以通過少樣本微調來嵌入任務,並進一步探索其在模型選擇和合併中的應用。我們希望Delta Activations能夠促進公開可用模型的重用實踐。代碼可在https://github.com/OscarXZQ/delta_activations獲取。
English
The success of powerful open source Large Language Models (LLMs) has enabled
the community to create a vast collection of post-trained models adapted to
specific tasks and domains. However, navigating and understanding these models
remains challenging due to inconsistent metadata and unstructured repositories.
We introduce Delta Activations, a method to represent finetuned models as
vector embeddings by measuring shifts in their internal activations relative to
a base model. This representation allows for effective clustering by domain and
task, revealing structure in the model landscape. Delta Activations also
demonstrate desirable properties: it is robust across finetuning settings and
exhibits an additive property when finetuning datasets are mixed. In addition,
we show that Delta Activations can embed tasks via few-shot finetuning, and
further explore its use for model selection and merging. We hope Delta
Activations can facilitate the practice of reusing publicly available models.
Code is available at https://github.com/OscarXZQ/delta_activations.