Exploring Context Window of Large Language Models via Decomposed Positional Vectors
<|reference_start|>Exploring Context Window of Large Language Models via Decomposed Positional Vectors: Transformer-based large language models (LLMs) typically have a limited context window, resulting in significant performance degradation when processing text beyond the length of the context window. Extensive studies have been proposed to extend the context window and achieve length extrapolation of LLMs, but there is still a lack of in-depth interpretation of these approaches. In this study, we explore the positional information within and beyond the context window for deciphering the underlying mechanism of LLMs. By using a mean-based decomposition method, we disentangle positional vectors from hidden states of LLMs and analyze their formation and effect on attention. Furthermore, when texts exceed the context window, we analyze the change of positional vectors in two settings, i.e., direct extrapolation and context window extension. Based on our findings, we design two training-free context window extension methods, positional vector replacement and attention window extension. Experimental results show that our methods can effectively extend the context window length.<|reference_end|>
@article{dong2024exploring,
    title={Exploring Context Window of Large Language Models via Decomposed
  Positional Vectors},
    author={Zican Dong, Junyi Li, Xin Men, Wayne Xin Zhao, Bingbing Wang, Zhen
  Tian, Weipeng Chen, Ji-Rong Wen},
    journal={arXiv preprint arXiv:2405.18009},
    year={2024},
    archivePrefix={arXiv},
    eprint={2405.18009},
    primaryClass={cs.CL cs.LG}
}