titleRethinking Sequence Compression with Test-time Regression
authorsSihan Yang, Jie Huang, Hanxuan Li, Yifan Guo, Weigao Sun, Yiran Zhong, Weiyang Liu
date2026-10-22
venuearXiv (preprint, not peer reviewed)
idarXiv:2610.31574
affiliationCUHK SphereLab
upvotes21 (Hugging Face Daily Papers, 2026-11-01)
linksabs pdf hf code
abstractSequence compression is a fundamental operation and a critical information bottleneck in efficient language and multimodal models, and yet prevailing approaches based on pooling or learned projections remain underperforming. We revisit sequence compression through the lens of test-time regression: input tokens define a regression problem whose fitted coefficients form the compressed representation. Importantly, the regression problem is learned end-to-end via backpropagation, while its coefficients are computed efficiently in closed form during the forward pass. This leads to TTR-Compressor, a general alternative to conventional pooling and projection-based compression. We evaluate TTR-Compressor as the compressor for block-wise sparse attention and the visual token merger for multimodal large language models. On block-wise sparse attention, TTR-Compressor improves RULER performance over attention-based compressors by a large margin. For visual token merging, it consistently outperforms the standard MLP merger and matches its performance with 55.6% fewer visual tokens. These results establish test-time regression as an effective primitive for sequence compression in efficient language and multimodal models.

cite

@misc{yang2026rethinking,
  title={Rethinking Sequence Compression with Test-time Regression},
  author={Sihan Yang and Jie Huang and Hanxuan Li and Yifan Guo and Weigao Sun and Yiran Zhong and Weiyang Liu},
  year={2026},
  eprint={2610.31574},
  archivePrefix={arXiv},
  url={https://arxiv.org/abs/2610.31574}
}