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CoT-Valve: Length-Compressible Chain-of-Thought Tuning

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arxiv 2502.09601 v1 pith:7XRLVTHD submitted 2025-02-13 cs.AI cs.CL

classification cs.AIcs.CL
keywords reasoningchainscot-valvechaininferencelengthtuningchain-of-thought
verification ladder T0 review T1 audit T2 compute T3 formal
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Chain-of-Thought significantly enhances a model's reasoning capability, but it also comes with a considerable increase in inference costs due to long chains. With the observation that the reasoning path can be easily compressed under easy tasks but struggle on hard tasks, we explore the feasibility of elastically controlling the length of reasoning paths with only one model, thereby reducing the inference overhead of reasoning models dynamically based on task difficulty. We introduce a new tuning and inference strategy named CoT-Valve, designed to allow models to generate reasoning chains of varying lengths. To achieve this, we propose to identify a direction in the parameter space that, when manipulated, can effectively control the length of generated CoT. Moreover, we show that this property is valuable for compressing the reasoning chain. We construct datasets with chains from long to short for the same questions and explore two enhanced strategies for CoT-Valve: (1) a precise length-compressible CoT tuning method, and (2) a progressive chain length compression approach. Our experiments show that CoT-Valve successfully enables controllability and compressibility of the chain and shows better performance than the prompt-based control. We applied this method to QwQ-32B-Preview, reducing reasoning chains on GSM8K from 741 to 225 tokens with a minor performance drop (95.07% to 94.92%) and on AIME from 6827 to 4629 tokens, with only one additional incorrect answer.

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Cited by 19 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. rePIRL: Learn PRM with Inverse RL for LLM Reasoning

    cs.LG 2026-02 unverdicted novelty 6.0 of 10

    rePIRL learns token-level process rewards for LLM reasoning via a guided-cost-learning-style IRL objective, and shows these rewards improve reasoning policies on math/coding benchmarks.

  2. Reconsidering Overthinking: Penalizing Internal and External Redundancy in CoT Reasoning

    cs.AI 2025-08 conditional novelty 6.0 of 10

    A dual-penalty RL method that compresses chain-of-thought traces by separately penalizing internal semantic stagnation and external post-answer continuation reduces reasoning length by about 40% while preserving accur...

  3. Do Thinking Tokens Help or Trap? Towards More Efficient Large Reasoning Model

    cs.CL 2025-06 conditional novelty 6.0 of 10

    Suppressing 'thinking tokens' in a 1.5B reasoning model preserves accuracy while cutting tokens, and the proposed DuP-PO RL method improves both accuracy and efficiency over GRPO.

  4. AALC: Large Language Model Efficient Reasoning via Adaptive Accuracy-Length Control

    cs.CL 2025-06 conditional novelty 6.0 of 10

    AALC, an accuracy-aware length reward, reduces reasoning-model response length by over 50% on math benchmarks while preserving or improving accuracy.

  5. Exploring and Exploiting the Inherent Efficiency within Large Reasoning Models for Self-Guided Efficiency Enhancement

    cs.AI 2025-06 conditional novelty 6.0 of 10

    Large reasoning models already contain the ability to reason concisely; steering their internal activations or rewarding brevity can cut reasoning length by up to half without hurting accuracy.

  6. How Far Are We from Optimal Reasoning Efficiency?

    cs.CL 2025-06 conditional novelty 6.0 of 10

    The authors define a reasoning efficiency frontier and a gap metric (REG), then train models with REO-RL to shrink the gap by at least 50% with only small accuracy losses.

  7. Is Your Model Thinking or Just Stagnating? PUMA: Diagnosing Reasoning Pathology via Phase-Momentum Alignment

    cs.AI 2026-07 conditional novelty 5.0 of 10

    PUMA detects when a reasoning model's entropy drop aligns with hidden-state momentum, truncates at that point, and reports improved accuracy-efficiency on 1.5B-32B reasoning models.

  8. LISA: Linear-Indexed Sparse Attention for Efficient Long-Context Reasoning

    cs.AI 2026-05 reject novelty 5.0 of 10

    LISA replaces standard attention with linear attention plus indexer-selected sparse attention, claiming O(nM) inference cost and accuracy gains, but the complexity analysis ignores the indexer's full-context scoring.

  9. Implicit Reasoning in Large Language Models: A Comprehensive Survey

    cs.CL 2025-09 conditional novelty 5.0 of 10

    A survey organizing implicit (silent) reasoning in LLMs into three execution paradigms, plus evidence, benchmarks, and challenges.

  10. ThinkDial: An Open Recipe for Controlling Reasoning Effort in Large Language Models

    cs.CL 2025-08 conditional novelty 5.0 of 10

    An open training recipe that teaches a 32B LLM to reason in three adjustable modes, cutting token use by half or three quarters with small accuracy losses.

  11. Think in Blocks: Adaptive Reasoning from Direct Response to Deep Reasoning

    cs.AI 2025-08 unverdicted novelty 5.0 of 10

    A training framework that makes LLMs predict an integer reasoning budget as a number of blocks and adapt reasoning depth to task difficulty.

  12. CoRE: Enhancing Metacognition with Label-free Self-evaluation in LRMs

    cs.LG 2025-07 conditional novelty 5.0 of 10

    A training-free and label-free detector of cyclic hidden-state patterns triggers early exit during chain-of-thought reasoning, reducing token length while mostly preserving or improving accuracy.

  13. Reasoning on a Budget: A Survey of Adaptive and Controllable Test-Time Compute in LLMs

    cs.AI 2025-07 conditional novelty 5.0 of 10

    The survey's L1/L2 taxonomy and benchmark show that current reasoning models waste compute on easy problems and underthink hard ones, motivating more adaptive inference.

  14. Efficient Reasoning Through Suppression of Self-Affirmation Reflections in Large Reasoning Models

    cs.CL 2025-06 conditional novelty 5.0 of 10

    Suppressing low-probability 'wait' tokens that trigger self-affirmation reflections shortens reasoning-model output by 8-18% with roughly unchanged accuracy.

  15. Fast on the Easy, Deep on the Hard: Efficient Reasoning via Powered Length Penalty

    cs.CL 2025-06 conditional novelty 5.0 of 10

    Reward shaping with a powered length penalty makes LLMs answer easy questions with far fewer tokens while preserving or slightly improving accuracy on hard math benchmarks.

  16. From Long to Short: LLMs Excel at Trimming Own Reasoning Chains

    cs.AI 2025-09 conditional novelty 4.0 of 10

    EDIT searches across step-count prompts to find the shortest reasoning path the model consistently answers correctly.

  17. Wait, We Don't Need to "Wait"! Removing Thinking Tokens Improves Reasoning Efficiency

    cs.CL 2025-06 conditional novelty 4.0 of 10

    Suppressing "Wait"-like reflection tokens at decode time reduces reasoning token counts by 27-51% across five R1-style model families, with mixed accuracy effects.

  18. Towards Concise and Adaptive Thinking in Large Reasoning Models: A Survey

    cs.AI 2025-07 conditional novelty 3.0 of 10

    A comprehensive review that categorizes methods for shortening and adaptively triggering chain-of-thought reasoning in large language models.

  19. Optimizing Length Compression in Large Reasoning Models

    cs.AI 2025-06

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