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The sampling Kaczmarz-Motzkin (SKM) method is a generalization of the randomized Kaczmarz and Motzkin methods. It first samples some rows of coefficient matrix randomly to build a set and then makes use of the maximum violation criterion…

Numerical Analysis · Mathematics 2020-11-16 Yanjun Zhang , Hanyu Li

This paper is about randomized iterative algorithms for solving a linear system of equations $X \beta = y$ in different settings. Recent interest in the topic was reignited when Strohmer and Vershynin (2009) proved the linear convergence…

Optimization and Control · Mathematics 2014-06-23 Aaditya Ramdas

We consider linear systems $Ax = b$ where $A \in \mathbb{R}^{m \times n}$ consists of normalized rows, $\|a_i\|_{\ell^2} = 1$, and where up to $\beta m$ entries of $b$ have been corrupted (possibly by arbitrarily large numbers). Haddock,…

Numerical Analysis · Mathematics 2021-07-13 Stefan Steinerberger

The Kaczmarz algorithm is an iterative method for solving systems of linear equations. We introduce a modified Kaczmarz algorithm for solving systems of linear equations in a distributed environment, i.e. the equations within the system are…

Numerical Analysis · Mathematics 2019-04-12 Chinmay Hegde , Fritz Keinert , Eric S. Weber

To find the least squares solution of a very large and inconsistent system of equations, one can employ the extended Kaczmarz algorithm. This method simultaneously removes the error term, such that a consistent system is asymptotically…

Numerical Analysis · Mathematics 2015-04-02 Stefania Petra , Constantin Popa

Randomized iterative algorithms for solving a factorized linear system, $\mathbf A\mathbf B\mathbf x=\mathbf b$ with $\mathbf A\in{\mathbb{R}}^{m\times \ell}$, $\mathbf B\in{\mathbb{R}}^{\ell\times n}$, and $\mathbf b\in{\mathbb{R}}^m$,…

Numerical Analysis · Mathematics 2023-07-25 Kui Du

We provide a complete characterization of the randomized Kaczmarz algorithm (RKA) for inconsistent linear systems. The Kaczmarz algorithm, known in some fields as the algebraic reconstruction technique, is a classical method for solving…

Numerical Analysis · Mathematics 2015-02-05 Chuang Wang , Ameya Agaskar , Yue M. Lu

The Kaczmarz method is an iterative projection scheme for solving con-sistent system $Ax = b$. It is later extended to the inconsistent and ill-posed linear problems. But the classical Kaczmarz method is sensitive to the correlation of the…

Numerical Analysis · Mathematics 2022-10-04 Chuan-gang Kang , Heng Zhou

This paper investigates the randomized version of the Kaczmarz method to solve linear systems in the case where the adjoint of the system matrix is not exact---a situation we refer to as "mismatched adjoint". We show that the method may…

Numerical Analysis · Mathematics 2018-03-09 Dirk A. Lorenz , Sean Rose , Frank Schöpfer

Randomized Kaczmarz is a simple iterative method for finding solutions of linear systems $Ax = b$. We point out that the arising sequence $(x_k)_{k=1}^{\infty}$ tends to converge to the solution $x$ in an interesting way: generically, as $k…

Numerical Analysis · Mathematics 2021-09-15 Stefan Steinerberger

We describe an asynchronous parallel variant of the randomized Kaczmarz (RK) algorithm for solving the linear system $Ax=b$. The analysis shows linear convergence and indicates that nearly linear speedup can be expected if the number of…

Numerical Analysis · Mathematics 2014-06-10 Ji Liu , Stephen J. Wright , Srikrishna Sridhar

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…

We develop a novel, fundamental and surprisingly simple randomized iterative method for solving consistent linear systems. Our method has six different but equivalent interpretations: sketch-and-project, constrain-and-approximate, random…

Numerical Analysis · Mathematics 2016-01-07 Robert M. Gower , Peter Richtárik

In this paper, we analyze the greedy randomized Kaczmarz (GRK) method proposed in Bai and Wu (SIAM J. Sci. Comput., 40(1):A592--A606, 2018) for solving linear systems. We develop more precise greedy probability criteria to effectively…

Numerical Analysis · Mathematics 2023-11-15 Yansheng Su , Deren Han , Yun Zeng , Jiaxin Xie

The Kaczmarz method is a way to iteratively solve a linear system of equations $Ax = b$. One interprets the solution $x$ as the point where hyperplanes intersect and then iteratively projects an approximate solution onto these hyperplanes…

Numerical Analysis · Mathematics 2024-11-12 Stefan Steinerberger

When solving linear systems $Ax=b$, $A$ and $b$ are given, but the measurements $b$ often contain corruptions. Inspired by recent work on the quantile-randomized Kaczmarz method, we propose an acceleration of the randomized Kaczmarz method…

Numerical Analysis · Mathematics 2024-10-18 Emeric Battaglia , Anna Ma

The Kaczmarz method is an algorithm for finding the solution to an overdetermined consistent system of linear equations Ax=b by iteratively projecting onto the solution spaces. The randomized version put forth by Strohmer and Vershynin…

Numerical Analysis · Mathematics 2011-02-15 Yonina C. Eldar , Deanna Needell

The randomized Kaczmarz methods are a popular and effective family of iterative methods for solving large-scale linear systems of equations, which have also been applied to linear feasibility problems. In this work, we propose a new block…

Optimization and Control · Mathematics 2024-06-19 Minxin Zhang , Jamie Haddock , Deanna Needell

Matrix factorization techniques compute low-rank product approximations of high dimensional data matrices and as a result, are often employed in recommender systems and collaborative filtering applications. However, many algorithms for this…

Numerical Analysis · Mathematics 2020-10-22 Edwin Chau , Jamie Haddock

Kaczmarz is one of the most prominent iterative solvers for linear systems of equations. Despite substantial research progress in recent years, the state-of-the-art Kaczmarz algorithms have not fully resolved the seesaw effect, a major…

Numerical Analysis · Mathematics 2025-09-24 Aneesh Panchal , Ratikanta Behera