Teaching diffusion language models when to commit a token, for a 10x decoding speedup on GSM8K
AspireAI community · arXiv
Diffusion large language models generate tokens in parallel but need many decoding rounds to finish a response. dSpark frames the problem as scheduling: a highly predictable token may add little context, while revealing a less predictable one can make several other positions predictable sooner. It constructs unmasking schedules that prioritize tokens whose reveal makes other positions easier to predict, then distills those schedules into the model with a KL-divergence regularizer to protect generation quality. On GSM8K the method reports 10.12x and 5.12x speedups over various baselines on LLaDA-8B-Instruct and Dream-7B-Instruct respectively while keeping task performance up. The results are on mathematical reasoning and code generation with those two model families, so the speedup is not yet demonstrated on long-context or agent workloads.
Read the story and explore more from the AspireAI community.
Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.