Diffusion models, based on discretizations of stochastic differential equations, are known for their generative performance.
A simplified theoretical framework has been proposed to analyze Euler-Maruyama discretization of variance-preserving SDEs in Denoising Diffusion Probabilistic Models (DDPMs).
The study leverages Gröenwall's inequality to establish a convergence rate of O(1/T^1/2) under Lipschitz assumptions, simplifying previous proofs.
Experiments validate the theory, confirming the error scaling, effectiveness of discrete noise over Gaussian noise, and the impact of incorrect noise scaling on performance.