Discrete Flow Matching Policy Optimization

Apr 7, 2026·
M. Su
Po-Chung (Bryan) Hsieh
Po-Chung (Bryan) Hsieh
,
W. Wu
,
M. Lu
,
J. Chen
,
J. Y. C. Hu
,
H. Liu
· 1 min read
Type
Publication
arXiv preprint arXiv:2604.06491
publications

DoMinO is a reinforcement learning framework for fine-tuning discrete flow-matching models. It formulates discrete flow-matching inference as an inner Markov decision process, which enables exact trajectory log-likelihood optimization. Fine-tuning uses REINFORCE- and PPO-based methods with cross-entropy and generalized KL regularization to mitigate reward hacking and preserve sequence naturalness.

On regulatory DNA and protein design, DoMinO outperforms prior state-of-the-art baselines by 10.6% on DNA predicted activity and 15.4% on protein pred-ddG.

My role: project co-lead. See the DoMinO project page.

Po-Chung (Bryan) Hsieh
Authors
M.S. Student in Electrical and Computer Engineering
I am an M.S. student in Electrical and Computer Engineering at UC San Diego, with a B.S. in Electrical Engineering from National Taiwan University. I build AI agents and reinforcement learning methods for scientific discovery, including multi-agent systems for biomedical feature discovery and policy optimization for discrete generative models, and I previously worked as an LLM engineer intern at the Inventec Artificial Intelligence Center.