Discrete Diffusion Models: Novel Analysis and New Sampler Guarantees

Fuente: arXiv
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Main Authors: Liang, Yuchen, Liang, Yingbin, Lai, Lifeng, Shroff, Ness
Format: Preprint
Published: 2025
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author Liang, Yuchen
Liang, Yingbin
Lai, Lifeng
Shroff, Ness
author_facet Liang, Yuchen
Liang, Yingbin
Lai, Lifeng
Shroff, Ness
contents Discrete diffusion models have recently gained significant prominence in applications involving natural language and graph data. A key factor influencing their effectiveness is the efficiency of discretized samplers. Among these, $τ$-leaping samplers have become particularly popular due to their theoretical and empirical success. However, existing theoretical analyses of $τ$-leaping often rely on somewhat restrictive and difficult-to-verify regularity assumptions, and their convergence bounds contain quadratic dependence on the vocabulary size. In this work, we introduce a new analytical approach for discrete diffusion models that removes the need for such assumptions. For the standard $τ$-leaping method, we establish convergence guarantees in KL divergence that scale linearly with vocabulary size, improving upon prior results with quadratic dependence. Our approach is also more broadly applicable: it provides the first convergence guarantees for other widely used samplers, including the Euler method and Tweedie $τ$-leaping. Central to our approach is a novel technique based on differential inequalities, offering a more flexible alternative to the traditional Girsanov change-of-measure methods. This technique may also be of independent interest for the analysis of other stochastic processes.
format Preprint
id arxiv_https___arxiv_org_abs_2509_16756
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Discrete Diffusion Models: Novel Analysis and New Sampler Guarantees
Liang, Yuchen
Liang, Yingbin
Lai, Lifeng
Shroff, Ness
Machine Learning
Signal Processing
Discrete diffusion models have recently gained significant prominence in applications involving natural language and graph data. A key factor influencing their effectiveness is the efficiency of discretized samplers. Among these, $τ$-leaping samplers have become particularly popular due to their theoretical and empirical success. However, existing theoretical analyses of $τ$-leaping often rely on somewhat restrictive and difficult-to-verify regularity assumptions, and their convergence bounds contain quadratic dependence on the vocabulary size. In this work, we introduce a new analytical approach for discrete diffusion models that removes the need for such assumptions. For the standard $τ$-leaping method, we establish convergence guarantees in KL divergence that scale linearly with vocabulary size, improving upon prior results with quadratic dependence. Our approach is also more broadly applicable: it provides the first convergence guarantees for other widely used samplers, including the Euler method and Tweedie $τ$-leaping. Central to our approach is a novel technique based on differential inequalities, offering a more flexible alternative to the traditional Girsanov change-of-measure methods. This technique may also be of independent interest for the analysis of other stochastic processes.
title Discrete Diffusion Models: Novel Analysis and New Sampler Guarantees
topic Machine Learning
Signal Processing
url https://arxiv.org/abs/2509.16756