Aussie AI

Long Context Chain-of-Thought (CoT)

  • Last Updated 19 March, 2025
  • by David Spuler, Ph.D.

What is Long Context Chain-of-Thought (CoT)?

Long context Chain-of-Thought (CoT) is the use of the CoT reasoning algorithm in an LLM with a long context window. Typically, this means a context of at least 128k, and an "ultralong" context is greater than a million tokens (becoming increasingly common).

The use of long context LLMs can be quite expensive, and this can be exacerbated by multi-step reasoning algorithms. However, there are various ways to lower CoT reasoning costs, by reducing the number of tokens used in the reasoning steps, skipping steps, or pruning redundant reasoning paths. Since the KV cache is the main inference bottleneck in long context processing, various KV cache compression optimizations can be used for faster processing of long queries, whether for reasoning models or other types of LLMs.

Research on Long CoT

Research papers include:

  • Jiaan Wang, Fandong Meng, Yunlong Liang, Jie Zhou, 23 Dec 2024, DRT-o1: Optimized Deep Reasoning Translation via Long Chain-of-Thought, https://arxiv.org/abs/2412.17498 https://github.com/krystalan/DRT-o1 (Examines similes and metaphors in literature using long CoT.)
  • Haotian Xu, Xing Wu, Weinong Wang, Zhongzhi Li, Da Zheng, Boyuan Chen, Yi Hu, Shijia Kang, Jiaming Ji, Yingying Zhang, Zhijiang Guo, Yaodong Yang, Muhan Zhang, Debing Zhang, 20 Jan 2025, RedStar: Does Scaling Long-CoT Data Unlock Better Slow-Reasoning Systems? https://arxiv.org/abs/2501.11284 https://huggingface.co/RedStar-Reasoning
  • Edward Yeo, Yuxuan Tong, Morry Niu, Graham Neubig, Xiang Yue, 5 Feb 2025, Demystifying Long Chain-of-Thought Reasoning in LLMs, https://arxiv.org/abs/2502.03373 https://github.com/eddycmu/demystify-long-cot
  • Kimi Team, Angang Du, Bofei Gao, Bowei Xing, Changjiu Jiang, Cheng Chen, Cheng Li, Chenjun Xiao, Chenzhuang Du, Chonghua Liao, Chuning Tang, Congcong Wang, (authors omitted), 22 Jan 2025, Kimi k1.5: Scaling Reinforcement Learning with LLMs, https://arxiv.org/abs/2501.12599 (Includes a "length penalty" to address token reduction.)
  • Zhong-Zhi Li, Duzhen Zhang, Ming-Liang Zhang, Jiaxin Zhang, Zengyan Liu, Yuxuan Yao, Haotian Xu, Junhao Zheng, Pei-Jie Wang, Xiuyi Chen, Yingying Zhang, Fei Yin, Jiahua Dong, Zhijiang Guo, Le Song, Cheng-Lin Liu, 25 Feb 2025 (v2), From System 1 to System 2: A Survey of Reasoning Large Language Models, https://arxiv.org/abs/2502.17419
  • Xiaoran Liu, Ruixiao Li, Mianqiu Huang, Zhigeng Liu, Yuerong Song, Qipeng Guo, Siyang He, Qiqi Wang, Linlin Li, Qun Liu, Yaqian Zhou, Xuanjing Huang, Xipeng Qiu, 24 Feb 2025, Thus Spake Long-Context Large Language Model, https://arxiv.org/abs/2502.17129 (Impressive survey of many techniques to improve efficiency and accuracy of long context processing in both inference and training, covering text, video and multimodal models.)
  • Yuchen Yan, Yongliang Shen, Yang Liu, Jin Jiang, Mengdi Zhang, Jian Shao, Yueting Zhuang, 13 Mar 2025 (v2), InftyThink: Breaking the Length Limits of Long-Context Reasoning in Large Language Models, https://arxiv.org/abs/2503.06692
  • Qiguang Chen, Libo Qin, Jinhao Liu, Dengyun Peng, Jiannan Guan, Peng Wang, Mengkang Hu, Yuhang Zhou, Te Gao, Wanxiang Che, 13 Mar 2025 (v2), Towards Reasoning Era: A Survey of Long Chain-of-Thought for Reasoning Large Language Models, https://arxiv.org/abs/2503.09567 (Massive and broad survey of all types of reasoning.)

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