Large language models (LLMs) have recently garnered significant interest. With in-context learning, LLMs achieve impressive results in various natural language tasks. However, the application of LLMs to sentence embeddings remains an area of ongoing research. In this work, we propose an in-context learning-based method aimed at improving sentence embeddings performance. Our approach involves adapting the previous prompt-based representation method for autoregressive models, constructing a demonstration set that enables LLMs to perform in-context learning, and scaling up the LLMs to different model sizes. Through extensive experiments, in-context learning enables LLMs to generate high-quality sentence embeddings without any fine-tuning. It helps LLMs achieve performance comparable to current contrastive learning methods. By scaling model size, we find scaling to more than tens of billion parameters harms the performance on semantic textual similarity (STS) tasks. However, the largest model outperforms other counterparts and achieves the new state-of-the-art result on transfer tasks. We also fine-tune LLMs with current contrastive learning approach, and the 2.7B OPT model, incorporating our prompt-based method, surpasses the performance of 4.8B ST5, achieving the new state-of-the-art results on STS tasks. Our code is available at https://github.com/kongds/scaling_sentemb.

通过上下文学习，我们提出了一种基于上下文学习的方法，旨在提高句子嵌入的性能。我们的方法能够使大型语言模型生成高质量的句子嵌入，并且在语义文本相似度任务上表现与当前对比学习方法相当。通过调整模型大小，我们发现超过几十亿参数的模型会对语义文本相似度任务的性能造成损害，但最大的模型超过了其他模型，并在迁移任务上取得了新的最先进结果。我们还使用当前的对比学习方法对大型语言模型进行了微调，将包含我们基于提示的方法的2.7B OPT模型的性能超过了4.8B ST5的性能，在语义文本相似度任务上实现了新的最先进结果。

利用大型语言模型扩展句子嵌入