TL;DR
Existing samplers for masked diffusion language models struggle with safely revealing multiple tokens simultaneously due to potential prediction conflicts. The proposed Attention-Discounted Adaptive Sampler (ADAS) modifies subset construction by discounting candidates that are uncertain when attending to already selected positions.
✦ Why It Matters
Engineers can leverage ADAS to improve the efficiency and accuracy of language model inference without extensive retraining.
Key Takeaways
Full Summary
Masked diffusion language models enhance efficiency by allowing multiple tokens to be predicted in parallel during inference. However, this parallelism can lead to issues when confident predictions are coupled with uncertain ones.
The Attention-Discounted Adaptive Sampler (ADAS) is introduced as a training-free reranking method that adjusts how candidates are selected based on their attention to already chosen tokens. Instead of imposing strict compatibility constraints, ADAS applies a soft penalty to candidates that are uncertain, allowing for more flexible decision-making.
Testing on models like LLaDA-8B-Base and Dream-7B-Base across datasets such as GSM8K and MATH500 showed that integrating ADAS with existing samplers like Top-k and Fast-dLLM led to significant performance improvements. Specifically, it achieved average gains of 9.11% and 10.46% in low-NFE (Number of Forward Evaluations) performance, with a minimal increase in computational cost.
These findings suggest that ADAS can enhance the quality of parallel decoding in masked diffusion models.
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