OPDLM-8B

OPDLM-8B

OPDLM-8B is a block diffusion language model (DLM) obtained by post-training an autoregressive language model (ARLM) into a diffusion language model via on-policy distillation. arXiv report: arxiv.org/abs/2606.06712

Highlights

• Converted, not pretrained from scratch: built from a strong ARLM, reusing its prior.
• Training-efficient: ~0.066B tokens of conversion vs. ~50B tokens for from-scratch DLM training (same base ARLM).
• Inference-efficient: parallel token decoding via block diffusion.

Model Details

• Developed by: DIVE Lab, Texas A&M University
• Base model: Qwen3-8B
• Model type: Block diffusion language model (decoder-based)
• Block size: 4
• Parameters: ~8B
• Language: English
• License: MIT

Training

• Method: On-policy distillation from a frozen ARLM teacher into a block DLM student.
• Conversion budget: ~0.066B tokens
• Data: opdlm_train_data

Evaluation

Decoding: static (one token per step)

Citation

@misc{su2026dataefficientautoregressivetodiffusionlanguagemodels,
      title={Data-Efficient Autoregressive-to-Diffusion Language Models via On-Policy Distillation}, 
      author={Xingyu Su and Jacob Helwig and Shubham Parashar and Atharv Chagi and Lakshmi Jotsna and Degui Zhi and James Caverlee and Dileep Kalathil and Shuiwang Ji},
      year={2026},
      eprint={2606.06712},
      archivePrefix={arXiv},
      primaryClass={cs.CL},
      url={https://arxiv.org/abs/2606.06712},
}