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The introduction of diffusion models in anomaly detection has paved the way for more effective and accurate image reconstruction in pathologies. However, the current limitations in controlling noise granularity hinder diffusion models'…

Computer Vision and Pattern Recognition · Computer Science 2023-06-01 Cosmin I. Bercea , Michael Neumayr , Daniel Rueckert , Julia A. Schnabel

Machine learning has been progressively generalised to operate within non-Euclidean domains, but geometrically accurate methods for learning on surfaces are still falling behind. The lack of closed-form Riemannian operators, the…

Computer Vision and Pattern Recognition · Computer Science 2026-03-18 Hippolyte Verninas , Caner Korkmaz , Stefanos Zafeiriou , Tolga Birdal , Simone Foti

High-dimensional data are often assumed to lie on lower-dimensional manifolds. We study how to construct diffusion processes on this data manifold using only point cloud samples and without access to charts, projections, or other geometric…

Machine Learning · Computer Science 2026-05-21 Victor Kawasaki-Borruat , Clara Grotehans , Pierre Vandergheynst , Adam Gosztolai

Finite difference methods (FDMs) are widely used for solving partial differential equations (PDEs) due to their relatively simple implementation. However, they face significant challenges when applied to non-rectangular domains and in…

Numerical Analysis · Mathematics 2025-07-08 Bin Han , Jiwoon Sim

Gaussian processes (GPs) are very widely used for modeling of unknown functions or surfaces in applications ranging from regression to classification to spatial processes. Although there is an increasingly vast literature on applications,…

Methodology · Statistics 2017-06-28 Lizhen Lin , Mu Niu , Pokman Cheung , David Dunson

We design a monotone meshfree finite difference method for linear elliptic equations in the non-divergence form on point clouds via a nonlocal relaxation method. The key idea is a novel combination of a nonlocal integral relaxation of the…

Numerical Analysis · Mathematics 2023-08-08 Qihao Ye , Xiaochuan Tian

This work presents a generalized boundary integral method for elliptic equations on surfaces, encompassing both boundary value and interface problems. The method is kernel-free, implying that the explicit analytical expression of the kernel…

Numerical Analysis · Mathematics 2025-08-25 Pengsong Yin , Wenjun YIng , Yulin Zhang , Han Zhou

We introduce meshfree finite difference methods for approximating nonlinear elliptic operators that depend on second directional derivatives or the eigenvalues of the Hessian. Approximations are defined on unstructured point clouds, which…

Numerical Analysis · Mathematics 2017-05-03 Brittany D. Froese

We propose Riemannian Denoising Diffusion Probabilistic Models (RDDPMs) for learning distributions on submanifolds of Euclidean space that are level sets of functions, including most of the manifolds relevant to applications. Existing…

Machine Learning · Computer Science 2026-02-17 Zichen Liu , Wei Zhang , Christof Schütte , Tiejun Li

We present Bayesian Diffusion Models (BDM), a prediction algorithm that performs effective Bayesian inference by tightly coupling the top-down (prior) information with the bottom-up (data-driven) procedure via joint diffusion processes. We…

Computer Vision and Pattern Recognition · Computer Science 2024-04-23 Haiyang Xu , Yu Lei , Zeyuan Chen , Xiang Zhang , Yue Zhao , Yilin Wang , Zhuowen Tu

Trefftz schemes are high-order Galerkin methods whose discrete spaces are made of elementwise exact solutions of the underlying PDE. Trefftz basis functions can be easily computed for many PDEs that are linear, homogeneous, and have…

Numerical Analysis · Mathematics 2026-03-10 Lise-Marie Imbert-Gérard , Andrea Moiola , Chiara Perinati , Paul Stocker

In latent diffusion models (LDMs), denoising diffusion process efficiently takes place on latent space whose dimension is lower than that of pixel space. Decoder is typically used to transform the representation in latent space to that in…

Machine Learning · Computer Science 2024-09-30 Seongmin Hong , Suh Yoon Jeon , Kyeonghyun Lee , Ernest K. Ryu , Se Young Chun

One of the fundamental problems in machine learning is the estimation of a probability distribution from data. Many techniques have been proposed to study the structure of data, most often building around the assumption that observations…

Machine Learning · Statistics 2013-02-22 Oren Rippel , Ryan Prescott Adams

Deep generative models have emerged as state-of-the-art for solving inverse problems, but applying them to inverse problems for PDEs, like electrical impedance tomography (EIT) remains challenging. Because physical domains are naturally…

Image and Video Processing · Electrical Eng. & Systems 2026-05-20 Giovanni S. Alberti , Damiana Lazzaro , Serena Morigi , Matteo Santacesaria , Shibo Wang

Ghost, or fictitious points allow to capture boundary conditions that are not located on the finite difference grid discretization. We explore in this paper the impact of ghost points on the stability of the explicit Euler finite difference…

Numerical Analysis · Mathematics 2023-08-22 Fabien Le Floc'h

We present a higher-order finite volume method for solving elliptic PDEs with jump conditions on interfaces embedded in a 2D Cartesian grid. Second, fourth, and sixth order accuracy is demonstrated on a variety of tests including problems…

Numerical Analysis · Mathematics 2023-08-09 Will Thacher , Hans Johansen , Daniel Martin

Solving partial differential equations (PDEs) on complex domains can present significant computational challenges. The Diffuse Domain Method (DDM) is an alternative that reformulates the partial differential equations on a larger, simpler…

Numerical Analysis · Mathematics 2025-07-24 Luke Benfield , Andreas Dedner

This paper develops expansive gradient dynamics in deep neural network-induced mapping spaces. Specifically, we generate tools and concepts for minimizing a class of energy functionals in an abstract Hilbert space setting covering a wide…

Optimization and Control · Mathematics 2025-07-21 Wolfgang Dahmen , Wuchen Li , Yuankai Teng , Zhu Wang

Diffusion models (DM) have achieved remarkable promise in image super-resolution (SR). However, most of them are tailored to solving non-blind inverse problems with fixed known degradation settings, limiting their adaptability to real-world…

Computer Vision and Pattern Recognition · Computer Science 2024-03-18 Feng Li , Yixuan Wu , Zichao Liang , Runmin Cong , Huihui Bai , Yao Zhao , Meng Wang

A gradient discretisation method (GDM), Gradient schemes, Convergence analysis, Existence of weak solutions, Anisotropic reaction diffusion models, Dirichlet and Neumann boundary conditions, Non conforming finite element methods, Finite…

Numerical Analysis · Mathematics 2020-09-02 Yahya Alnashri , Hasan Alzubaidi