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Model-based iterative reconstruction plays a key role in solving inverse problems. However, the associated minimization problems are generally large-scale, nonsmooth, and sometimes even nonconvex, which present challenges in designing…

Image and Video Processing · Electrical Eng. & Systems 2025-10-21 Tao Hong , Zhaoyi Xu , Jason Hu , Jeffrey A. Fessler

This work addresses inverse linear optimization where the goal is to infer the unknown cost vector of a linear program. Specifically, we consider the data-driven setting in which the available data are noisy observations of optimal…

Optimization and Control · Mathematics 2021-12-07 Rishabh Gupta , Qi Zhang

The construction of fast iterative solvers for the indefinite time-harmonic Maxwell's system at mid- to high-frequency is a problem of great current interest. Some of the difficulties that arise are similar to those encountered in the case…

Numerical Analysis · Mathematics 2024-08-06 Marcella Bonazzoli , Victorita Dolean , Ivan Graham , Euan Spence , Pierre-Henri Tournier

We present a novel method called TESALOCS (TEnsor SAmpling and LOCal Search) for multidimensional optimization, combining the strengths of gradient-free discrete methods and gradient-based approaches. The discrete optimization in our method…

Optimization and Control · Mathematics 2025-05-20 Konstantin Sozykin , Andrei Chertkov , Anh-Huy Phan , Ivan Oseledets , Gleb Ryzhakov

Inference scaling methods for LLMs often rely on decomposing problems into steps (or groups of tokens), followed by sampling and selecting the best next steps. However, these steps and their sizes are often predetermined or manually…

In this paper we present an overview of recent progress on the development and analysis of domain decomposition preconditioners for discretised Helmholtz problems, where the preconditioner is constructed from the corresponding problem with…

Numerical Analysis · Mathematics 2016-06-24 I. G. Graham , E. A. Spence , E. Vainikko

Fractional order models have proven to be a very useful tool for the modeling of the mechanical behaviour of viscoelastic materials. Traditional numerical solution methods exhibit various undesired properties due to the non-locality of the…

Numerical Analysis · Mathematics 2023-01-30 Kai Diethelm

We present a space-time multiscale method for a parabolic model problem with an underlying coefficient that may be highly oscillatory with respect to both the spatial and the temporal variables. The method is based on the framework of the…

Numerical Analysis · Mathematics 2021-12-13 Per Ljung , Roland Maier , Axel Målqvist

We study preconditioners for a model problem describing the coupling of two elliptic subproblems posed over domains with different topological dimension by a parameter dependent constraint. A pair of parameter robust and efficient…

Numerical Analysis · Mathematics 2018-04-11 Miroslav Kuchta , Magne Nordaas , Joris C. G. Verschaeve , Mikael Mortensen , Kent-Andre Mardal

The study deals with the parallelization of finite element based Navier-Stokes codes using domain decomposition and state-ofart sparse direct solvers. There has been significant improvement in the performance of sparse direct solvers.…

Distributed, Parallel, and Cluster Computing · Computer Science 2009-11-05 Mandhapati P. Raju , Siddhartha Khaitan

We consider the use of multipreconditioning, which allows for multiple preconditioners to be applied in parallel, on high-frequency Helmholtz problems. Typical applications present challenging sparse linear systems which are complex…

Numerical Analysis · Mathematics 2025-05-19 Niall Bootland , Tyrone Rees

This paper presents an efficient Krylov subspace iterative solver for the three-dimensional (3D) Helmholtz equation with non-constant coefficients and absorbing boundary conditions, combining high-resolution compact schemes with low-order…

Numerical Analysis · Mathematics 2026-02-10 Yury Gryazin , Ron Gonzales , Xiaoye Sherry Li

We are interested in high-order linear multistep schemes for time discretization of adjoint equations arising within optimal control problems. First we consider optimal control problems for ordinary differential equations and show loss of…

Numerical Analysis · Mathematics 2018-07-24 Giacomo Albi , Michael Herty , Lorenzo Pareschi

Preconditioning of a linear system obtained from spectral discretization of time-dependent PDEs often results in a full matrix which is expensive to compute and store specially when the problem size increases. A matrix-free implementation…

Statistics Theory · Mathematics 2016-06-09 A. Ghasemi , L. K. Taylor

Cooperative Co-evolution, through the decomposition of the problem space, is a primary approach for solving large-scale global optimization problems. Typically, when the subspaces are disjoint, the algorithms demonstrate significantly both…

Neural and Evolutionary Computing · Computer Science 2025-03-31 Wenjie Qiu , Hongshu Guo , Zeyuan Ma , Yue-Jiao Gong

The two-scale computational homogenization method is proposed for modelling of locally periodic fluid-saturated media subjected a to large deformation induced by quasistatic loading. The periodic heterogeneities are relevant to the…

Numerical Analysis · Mathematics 2022-02-11 Vladimír Lukeš , Eduard Rohan

The reduction of computational costs in the numerical solution of nonstationary problems is achieved through splitting schemes. In this case, solving a set of less computationally complex problems provides the transition to a new level in…

Numerical Analysis · Mathematics 2022-10-26 Petr N. Vabishchevich

We study the finite element approximation of linear second-order elliptic partial differential equations in nondivergence form with highly heterogeneous diffusion and drift coefficients. A generalized Cordes condition is imposed to…

Numerical Analysis · Mathematics 2026-04-17 Moritz Hauck , Roland Maier , Timo Sprekeler

In this work we propose and analyze a novel Hybrid High-Order discretization of a class of (linear and) nonlinear elasticity models in the small deformation regime which are of common use in solid mechanics. The proposed method is valid in…

Numerical Analysis · Mathematics 2017-07-10 Michele Botti , Daniele Di Pietro , Pierre Sochala

The preconditioned iterative solution of large-scale saddle-point systems is of great importance in numerous application areas, many of them involving partial differential equations. Robustness with respect to certain problem parameters is…

Numerical Analysis · Mathematics 2021-04-22 Roland Herzog