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In recent work, Li et al.\ (Comm.\ Math.\ Sci., 7:81-107, 2009) developed a diffuse-domain method (DDM) for solving partial differential equations in complex, dynamic geometries with Dirichlet, Neumann, and Robin boundary conditions. The…

Numerical Analysis · Mathematics 2015-05-18 Karl Yngve Lervåg , John Lowengrub

In this paper, an upwind GFDM is developed for the coupled heat and mass transfer problems in porous media. GFDM is a meshless method that can obtain the difference schemes of spatial derivatives by using Taylor expansion in local node…

Numerical Analysis · Mathematics 2022-05-02 Xiang Rao

Our goal is to extend the denoising diffusion implicit model (DDIM) to general diffusion models~(DMs) besides isotropic diffusions. Instead of constructing a non-Markov noising process as in the original DDIM, we examine the mechanism of…

Machine Learning · Computer Science 2023-03-24 Qinsheng Zhang , Molei Tao , Yongxin Chen

We consider a model convection-diffusion problem and present our recent numerical and analysis results regarding mixed finite element formulation and discretization in the singular perturbed case when the convection term dominates the…

Numerical Analysis · Mathematics 2024-02-07 Constantin Bacuta , Daniel Hayes , Tyler O'Grady

Convection-diffusion-reaction equations model the conservation of scalar quantities. From the analytic point of view, solution of these equations satisfy under certain conditions maximum principles, which represent physical bounds of the…

Numerical Analysis · Mathematics 2023-05-24 Gabriel R. Barrenechea , Volker John , Petr Knobloch

Diffusion models generate data by learning to reverse a forward process, where samples are progressively perturbed with Gaussian noise according to a predefined noise schedule. From a geometric perspective, each noise schedule corresponds…

Image and Video Processing · Electrical Eng. & Systems 2025-10-21 Teng Zhang , Hongxu Jiang , Kuang Gong , Wei Shao

In this paper, optimal control problems governed by diffusion equations with Dirichlet and Neumann boundary conditions are investigated in the framework of the gradient discretisation method. Gradient schemes are defined for the optimality…

Numerical Analysis · Mathematics 2018-10-09 Jerome Droniou , Neela Nataraj , Devika Shylaja

A Lagrangian numerical scheme for solving nonlinear degenerate Fokker-Planck equations in space dimensions $d\ge2$ is presented. It applies to a large class of nonlinear diffusion equations, whose dynamics are driven by internal energies…

Numerical Analysis · Mathematics 2018-06-18 José A. Carrillo , Bertram Düring , Daniel Matthes , David S. McCormick

Coupled nonlinear system of reaction-diffusion equations describing multi-component (species) interactions with heterogeneous coefficients is considered. Finite volume method based approximation for the space is used to construct…

Numerical Analysis · Mathematics 2022-09-13 Maria Vasilyeva , Alexey Sadovski , D. Palaniappan

Diffusion models have shown remarkable empirical success in sampling from rich multi-modal distributions. Their inference relies on numerically solving a certain differential equation. This differential equation cannot be solved in closed…

Machine Learning · Computer Science 2026-01-16 Khashayar Gatmiry , Sitan Chen , Adil Salim

The accurate numerical simulation of turbulent incompressible flows is a challenging topic in computational fluid dynamics. For discretisation methods to be robust in the under-resolved regime, mass conservation as well as energy stability…

Computational Physics · Physics 2025-10-20 Niklas Fehn , Martin Kronbichler , Christoph Lehrenfeld , Gert Lube , Philipp W. Schroeder

We introduce the Fixed Point Diffusion Model (FPDM), a novel approach to image generation that integrates the concept of fixed point solving into the framework of diffusion-based generative modeling. Our approach embeds an implicit fixed…

Computer Vision and Pattern Recognition · Computer Science 2024-01-18 Xingjian Bai , Luke Melas-Kyriazi

Diffusion models are getting popular in generative image and video synthesis. However, due to the diffusion process, they require a large number of steps to converge. To tackle this issue, in this paper, we propose to perform the diffusion…

Computer Vision and Pattern Recognition · Computer Science 2023-09-06 Yuanhao Gong

In this paper we present a general, axiomatical framework for the rigorous approximation of invariant densities and other important statistical features of dynamics. We approximate the system trough a finite element reduction, by composing…

Dynamical Systems · Mathematics 2023-04-05 Stefano Galatolo , Maurizio Monge , Isaia Nisoli , Federico Poloni

Recent literature has effectively leveraged diffusion models trained on continuous variables as priors for solving inverse problems. Notably, discrete diffusion models with discrete latent codes have shown strong performance, particularly…

Computer Vision and Pattern Recognition · Computer Science 2025-09-22 Naoki Murata , Chieh-Hsin Lai , Yuhta Takida , Toshimitsu Uesaka , Bac Nguyen , Stefano Ermon , Yuki Mitsufuji

Diffusion models are the de facto approach for generating high-quality images and videos, but learning high-dimensional models remains a formidable task due to computational and optimization challenges. Existing methods often resort to…

Computer Vision and Pattern Recognition · Computer Science 2024-09-04 Jiatao Gu , Shuangfei Zhai , Yizhe Zhang , Josh Susskind , Navdeep Jaitly

The balancing domain decomposition methods (BDDC) are originally introduced for symmetric positive definite systems and have been extended to the nonsymmetric positive definite system from the linear finite element discretization of…

Numerical Analysis · Mathematics 2021-03-18 Xuemin Tu , Jinjin Zhang

The diffusion model has recently emerged as a potent approach in computer vision, demonstrating remarkable performances in the field of generative artificial intelligence. Capable of producing high-quality synthetic images, diffusion models…

Image and Video Processing · Electrical Eng. & Systems 2025-05-14 Abdullah , Tao Huang , Ickjai Lee , Euijoon Ahn

Diffusion models have quickly become some of the most popular and powerful generative models for high-dimensional data. The key insight that enabled their development was the realization that access to the score -- the gradient of the…

Machine Learning · Computer Science 2025-12-01 Zhenghan Fang , Mateo Díaz , Sam Buchanan , Jeremias Sulam

Finite volume methods (FVMs) constitute a popular class of methods for the numerical simulation of fluid flows. Among the various components of these methods, the discretisation of the gradient operator has received less attention despite…

Numerical Analysis · Computer Science 2018-01-03 Alexandros Syrakos , Stylianos Varchanis , Yannis Dimakopoulos , Apostolos Goulas , John Tsamopoulos