ZJU-OmniAI releases DTCA: token-level credit assignment for RL in diffusion language models, improves MATH500 by up to 9.0 points

DTCA assigns credit to individual tokens during reinforcement learning for diffusion language models, boosting math reasoning performance.

HeyHomees Lab Notes · No. 12 · ZJU-OmniAI · Published October 29, 2026

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In 30 seconds

What is it?

DTCA is a framework for token-level credit assignment in reinforcement learning for diffusion language models. It measures token contributions by the improvement in prediction confidence of remaining masked positions after token commitment and groups signals by part-of-speech categories.

How does it work?

DTCA selects informative denoising timesteps using contribution weights, assigns token-level learning signals during RL training, and calibrates these signals according to token-level entropy changes caused by policy updates. The implementation builds on RLDF/Drift and incorporates ideas from dLLM-RL, Fast-dLLM, and OPEFO.

How well does it do?

Experiments on LLaDA-8B-Instruct show DTCA consistently improves mathematical reasoning, achieving gains of up to 9.0 points on MATH500 and 5.3 points on GSM8K over the base model.

What does it need to run?

The code runs on Linux with Python 3.10 or 3.11, requires a CUDA-compatible PyTorch installation, and uses Accelerate and DeepSpeed ZeRO-3 for training.

By the numbers

The honest read

The reported gains of up to 9.0 points on MATH500 and 5.3 points on GSM8K are self-reported by the authors and reflect improvements over their base LLaDA-8B-Instruct model under the specific evaluation settings described. The figures do not indicate absolute performance levels, nor do they compare DTCA to other RL or diffusion methods beyond the base model. No external benchmarks or third-party evaluations are provided. The code and experiments are limited to the LLaDA-8B-Instruct model and the listed math datasets; applicability to other models or tasks is not demonstrated.

What we don't know yet

Sources

Researched and drafted with AI from the sources above; every figure is checked against them by code before it is published, and a line that fails is dropped.

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