PJiNH/QFFT-repro-LIMO-SFT-7B

QFFT-repro-LIMO-SFT-7B

This is the LIMO / SFT baseline from QFFT: Question-Free Fine-Tuning for Adaptive Reasoning (Liu et al., 2025, arXiv:2506.12860), trained independently to reproduce the paper.

• —It is not the authors' checkpoint.
• —It is not affiliated with or endorsed by the QFFT authors, Qwen / Alibaba Cloud, or the dataset authors.

• —Code, training configs, data notices, evaluation outputs and research notes: https://github.com/RomEscape/Research-Question_Free-
• —Base model: Qwen/Qwen2.5-7B-Instruct (Apache-2.0). These weights are a full fine-tune of that model, so they are a modified version of it.
• —Companion model trained on the same responses without questions: PJiNH/QFFT-repro-LIMO-QFFT-7B

Training

The questions and responses are exactly those of GAIR/LIMO (817/817, same order). The hyperparameters above match the paper's Table 5, which states that SFT and QFFT share one set of hyperparameters.

Known differences from the original setup:

• —Input format (our choice): SFT is the system prompt plus the question. The paper does not specify the SFT input format, and the authors released neither SFT data nor SFT checkpoints.
• —Hyperparameter source: the paper's Appendix A.2 says the SFT baselines follow the official S1, LIMO and Sky-T1 hyperparameters, which contradicts Table 5. We used Table 5.
• —GPU count and loss grouping: we used 1 GPU with gradient accumulation 8. The paper gives the batch size (8) but not the GPU count. The authors' released QFFT checkpoints record gradient accumulation 2.
• —Attention and DeepSpeed: SDPA instead of FlashAttention-2, and DeepSpeed ZeRO-2 with CPU optimizer offload instead of ZeRO-3 from the upstream config.
• —Library versions: transformers 4.52.1 and PyTorch 2.13, newer than the authors' checkpoints (transformers 4.51.0, PyTorch 2.6).

Evaluation (this reproduction)

Settings follow the released eval/eval.sh:

• —Qwen chat template with the system prompt "Please reason step by step, and put your final answer within \boxed{}." The paper's Figure 8 writes $\boxed{}$; the released code, used here, has no $.
• —temperature 0.6, top-p 1.0, at most 32,000 new tokens, 16 samples per problem, one vLLM 0.11.0 engine on one GPU.

The paper text states a 32,768-token budget; the released code uses 32,000. The table columns are:

• —Acc: accuracy averaged over the 16 samples.
• —Tokens: mean generated length.
• —RAK: the paper's Definition 2, with Qwen2.5-7B-Instruct as the reference, averaged over the 16 runs.

Usage

from vllm import LLM, SamplingParams

llm = LLM(model="PJiNH/QFFT-repro-LIMO-SFT-7B")
tok = llm.get_tokenizer()
messages = [
    {"role": "system", "content": "Please reason step by step, and put your final answer within \\boxed{}."},
    {"role": "user", "content": "What is the sum of the first 50 positive odd integers?"},
]
prompt = tok.apply_chat_template(messages, tokenize=False, add_generation_prompt=True)
out = llm.generate([prompt], SamplingParams(temperature=0.6, top_p=1.0, max_tokens=32000))
print(out[0].outputs[0].text)

License and data terms

• —Weights: Apache-2.0, inherited from Qwen2.5-7B-Instruct. The LICENSE file in this repository carries the original notice, Copyright 2024 Alibaba Cloud. The change is the full fine-tuning described above.
• —Training data: GAIR/LIMO, Apache-2.0 per its dataset card (the LIMO project README says MIT). Please cite LIMO (Ye et al., 2025, arXiv:2502.03387). According to the LIMO paper, its reasoning traces were produced with DeepSeek-R1 and other models, and the problems come from sources such as NuminaMath-CoT, MATH and AIME.
• —Full notices: THIRD_PARTY_NOTICES.md in the GitHub repository.

Citation

Please cite the QFFT paper (arXiv:2506.12860) and the LIMO paper (arXiv:2502.03387).