Paper Overview
Field: Machine Learning Authors: Daniil Dmitriev, Zhihan Huang, Yuting Wei Published: 2025-08-26 arXiv: 2508.17627
Summary
Discrete diffusion models offer a promising alternative to autoregressive generation by enabling parallel updates, but their sampling efficiency can depend strongly on the choice of the forward process and the sampler. For the uniform forward process, existing lower bounds for the standard \(\tau\)-leaping sampler scale linearly with the ambient dimension \(d\), raising the question of whether this dependence is intrinsic to the forward process. This paper answers the question in the negative.
The authors consider a first-order sampler based on the leave-one-out denoiser for uniform and remasking processes, whose coordinate updates can be performed in parallel. In both cases, the sampler can correct denoising mistakes during the sampling process, which becomes necessary when many coordinates are updated simultaneously.
Main Result
The key theorem establishes an adaptive sampling guarantee: up to a logarithmic factor,
discretization steps suffice to achieve sampling error \(O(\varepsilon_{\mathrm{score}} + \varepsilon)\), where \(\varepsilon_{\mathrm{score}}\) is the score estimation error.
Consequently, the sampling complexity is governed by the intrinsic dependency structure of the target distribution—measured by its dual total correlation \(\mathrm{DTC}(X_0)\)—rather than directly by the ambient dimension \(d\).
Source: arXiv:2508.17627
*Auto-collected on 2026-08-26.*