nics-efc/TaH-plus-1.7B

TEXT GENERATIONPricing:Input $0.32 / Cached $0.064 / Output $1.6Concurrent Unit Cost:1Model Size:2BQuant:BF16Context Size:32kTool Calling:SupportedPublished:Nov 23, 2025License:apache-2.0Architecture:Transformer0.0K Open Weights Featherless Exclusive Cold

TaH-plus-1.7B is a 2 billion parameter language model developed by nics-efc, designed for enhanced reasoning in math, code, and science domains. It utilizes a novel Think-at-Hard (TaH) mechanism with a neural decider to selectively initiate latent iterations, improving accuracy while minimizing computational overhead. This model achieves significant accuracy gains over baselines by applying a second iteration only when necessary, making it efficient for complex reasoning tasks. Its 32768 token context length further supports handling extensive problem descriptions and data.

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TaH-plus-1.7B: Efficient Reasoning with Selective Latent Iterations

TaH-plus-1.7B is a 2 billion parameter model developed by nics-efc, specifically trained on a diverse mixture of math, code, and science data. Its core innovation lies in the Think-at-Hard (TaH) mechanism, which employs a neural decider to dynamically determine when to initiate latent iterations, rather than performing them for all output tokens.

Key Capabilities & Innovations

  • Selective Latent Iterations: The TaH mechanism allows the model to perform a second iteration only when deemed necessary by a neural decider. This significantly improves efficiency by exempting approximately 94% of tokens from the second iteration.
  • Enhanced Reasoning Performance: Compared to baselines that iterate twice for all tokens, TaH-plus-1.7B delivers 8.1-11.3% accuracy gains. Against strong single-iteration Qwen3 models fine-tuned with the same data, it still achieves 4.0-5.0% accuracy improvements.
  • Parameter Efficiency: When incorporating less than 3% additional parameters from LoRA and the iteration decider, the accuracy gains further increase to 8.5-12.6% and 5.3-5.4% respectively, demonstrating efficient performance enhancement.
  • Domain Specialization: The model is specifically trained on math, code, and science data, making it well-suited for tasks requiring robust reasoning in these technical fields.

Good For

  • Applications requiring efficient and accurate reasoning in mathematics, coding, and scientific problem-solving.
  • Scenarios where computational efficiency is crucial, as the selective iteration reduces redundant processing.
  • Developers looking for a model that can handle complex reasoning tasks with a 32768 token context length.