X-Coder-SFT-Qwen3-8B

X-Coder-SFT-Qwen3-8B is a code generation model fine-tuned on fully synthetic instruction data, designed for competitive programming tasks. It serves as the foundation for subsequent RLVR training.

Model Description

• Base Model: Qwen/Qwen3-8B-Base
• Training Method: Supervised Fine-Tuning (SFT)
• Training Data: IIGroup/X-Coder-SFT-376k
• Parameters: 8B

Training

This model was trained using ms-swift. For training details and code, please refer to the X-Coder GitHub repository.

Training Hyperparameters

Parameter	Value
Base Model	Qwen/Qwen3-8B-Base
Training Type	Full Parameter
Epochs	8
Global Batch Size	128
Learning Rate	5e-5
Max Grad Norm	1.0
Max Length	32768
Torch Dtype	bfloat16
DeepSpeed	Zero3 Offload (80GB VRAM) / Zero2 (142GB VRAM)
Packing	True (2x faster training, slightly worse performance)

Performance on LiveCodeBench v5.

Recommended Inference Parameters

Parameter	Value
temperature	0.6
top_p	0.95
top_k	20 (or -1 to disable)
max_new_tokens	32768

Usage

from transformers import AutoModelForCausalLM, AutoTokenizer

model_name = "IIGroup/X-Coder-SFT-Qwen3-8B"
tokenizer = AutoTokenizer.from_pretrained(model_name)
model = AutoModelForCausalLM.from_pretrained(model_name, device_map="auto")

prompt = "Write a Python function to solve the two sum problem."
inputs = tokenizer(prompt, return_tensors="pt").to(model.device)
outputs = model.generate(
    **inputs,
    max_new_tokens=32768,
    temperature=0.6,
    top_p=0.95,
    top_k=20,
    do_sample=True
)
print(tokenizer.decode(outputs[0], skip_special_tokens=True))

Related Models

• RL Model: IIGroup/X-Coder-RL-Qwen3-8B - RLVR trained version achieving 64.0 on LiveCodeBench

Citation

@misc{wu2026xcoderadvancingcompetitiveprogramming,
      title={X-Coder: Advancing Competitive Programming with Fully Synthetic Tasks, Solutions, and Tests}, 
      author={Jie Wu and Haoling Li and Xin Zhang and Jiani Guo and Jane Luo and Steven Liu and Yangyu Huang and Ruihang Chu and Scarlett Li and Yujiu Yang},
      year={2026},
      eprint={2601.06953},
      archivePrefix={arXiv},
      primaryClass={cs.CL},
      url={https://arxiv.org/abs/2601.06953}, 
}

License

This project is licensed under the Apache License 2.0.