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The Kaczmarz algorithm is an iterative method that solves linear systems of equations. It stands out among iterative algorithms when dealing with large systems for two reasons. First, at each iteration, the Kaczmarz algorithm uses a single…

Numerical Analysis · Mathematics 2024-04-10 Inês A. Ferreira , Juan A. Acebrón , José Monteiro

Randomized iterative algorithms, such as the randomized Kaczmarz method, have gained considerable popularity due to their efficacy in solving matrix-vector and matrix-matrix regression problems. Our present work leverages the insights…

Kaczmarz method is one popular iterative method for solving inverse problems, especially in computed tomography. Recently, it was established that a randomized version of the method enjoys an exponential convergence for well-posed problems,…

Numerical Analysis · Mathematics 2017-12-06 Yuling Jiao , Bangti Jin , Xiliang Lu

The aim of this paper is to investigate the use of an entropic projection method for the iterative regularization of linear ill-posed problems. We derive a closed form solution for the iterates and analyze their convergence behaviour both…

Optimization and Control · Mathematics 2020-01-29 Martin Burger , Elena Resmerita , Martin Benning

In this paper we make a theoretical analysis of the convergence rates of Kaczmarz and Extended Kaczmarz projection algorithms for some of the most practically used control sequences. We first prove an at least linear convergence rate for…

Numerical Analysis · Mathematics 2017-01-30 Constantin Popa

Motivated by the randomized sketch to solve a variety of problems in scientific computation, we improve both the maximal weighted residual Kaczmarz method and the randomized block average Kaczmarz method using two new randomized sketch…

Numerical Analysis · Mathematics 2025-11-18 Haochen Jiang , Dongdong Liu , Xianping Wu , Xu Yang

This work unifies the analysis of various randomized methods for solving linear and nonlinear inverse problems by framing the problem in a stochastic optimization setting. By doing so, we show that many randomized methods are variants of a…

Numerical Analysis · Mathematics 2023-06-21 Jonathan Wittmer , C. G. Krishnanunni , Hai V. Nguyen , Tan Bui-Thanh

Randomized linear system solvers have become popular as they have the potential to reduce floating point complexity while still achieving desirable convergence rates. One particularly promising class of methods, random sketching solvers,…

Numerical Analysis · Mathematics 2020-12-23 Vivak Patel , Mohammad Jahangoshahi , Daniel Adrian Maldonado

The method of Alternating Projections (AP) is a fundamental iterative technique with applications to problems in machine learning, optimization and signal processing. Examples include the Gauss-Seidel algorithm which is used to solve…

Numerical Analysis · Mathematics 2025-06-03 Alireza Entezari , Arunava Banerjee , Leila Kalantari

Randomized iterative methods, such as the Kaczmarz method and its variants, have gained growing attention due to their simplicity and efficiency in solving large-scale linear systems. Meanwhile, absolute value equations (AVE) have attracted…

Numerical Analysis · Mathematics 2025-05-13 Jiaxin Xie , Hou-Duo Qi , Deren Han

Random projections or sketching are widely used in many algorithmic and learning contexts. Here we study the performance of iterative Hessian sketch for least-squares problems. By leveraging and extending recent results from random matrix…

Optimization and Control · Mathematics 2020-10-26 Jonathan Lacotte , Sifan Liu , Edgar Dobriban , Mert Pilanci

Iterative phase retrieval algorithms typically employ projections onto constraint subspaces to recover the unknown phases in the Fourier transform of an image, or, in the case of x-ray crystallography, the electron density of a molecule.…

Numerical Analysis · Mathematics 2025-10-20 Veit Elser

The randomized Kaczmarz method and its accelerated variants are a powerful class of iterative methods for solving large-scale linear systems, offering guaranteed convergence with low per-iteration cost. However, their numerical stability…

Numerical Analysis · Mathematics 2026-05-19 Michał Dereziński , Ethan N. Epperly , Deanna Needell , Alexander Xue

Generalized alternating projections is an algorithm that alternates relaxed projections onto a finite number of sets to find a point in their intersection. We consider the special case of two linear subspaces, for which the algorithm…

Optimization and Control · Mathematics 2017-03-31 Mattias Fält , Pontus Giselsson

In this paper, by regarding the two-subspace Kaczmarz method [20] as an alternated inertial randomized Kaczmarz algorithm we present a new convergence rate estimate which is shown to be better than that in [20] under a mild condition.…

Numerical Analysis · Mathematics 2023-06-16 Songnian He , Ziting Wang , Qiao-Li Dong

In this paper, we derive a practical, general framework for creating adaptive iterative (linearization or splitting) algorithms to solve multi-physics problems. This means that, given an iterative method, we derive \textit{a posteriori}…

Numerical Analysis · Mathematics 2026-01-26 Jakob S. Stokke , Kundan Kumar , Florin A. Radu

We use simple equations in order to compare the basins of attraction on the complex plane, corresponding to a large collection of numerical methods, of several order. Two cases are considered, regarding the total number of the roots, which…

Numerical Analysis · Mathematics 2024-12-20 Euaggelos E. Zotos , Md Sanam Suraj , Amit Mittal , Rajiv Aggarwal

Solving linear systems of equations is a fundamental problem in mathematics. When the linear system is so large that it cannot be loaded into memory at once, iterative methods such as the randomized Kaczmarz method excel. Here, we extend…

Numerical Analysis · Mathematics 2020-06-03 Anna Ma , Denali Molitor

Randomized iterative algorithms have attracted much attention in recent years because they can approximately solve large-scale linear systems of equations without accessing the entire coefficient matrix. In this paper, we propose two novel…

Numerical Analysis · Mathematics 2021-10-22 Kui Du , Xiao-Hui Sun

The randomized version of the Kaczmarz method for the solution of linear systems is known to converge linearly in expectation. In this work we extend this result and show that the recently proposed Randomized Sparse Kaczmarz method for…

Optimization and Control · Mathematics 2016-10-11 Frank Schöpfer , Dirk A. Lorenz