activity
20212026
most citedAn accelerated randomized Bregman-Kaczmarz method for strongly convex linearly constraint optimization

5 citations · 6 across the 10 of their papers we have counts for

collaborators

10 papers

math.NA2026

A Tensor Greedy Double-Block Extended Kaczmarz Method for Inconsistent Tensor Linear Systems under the t-product

Jérémie Mabiala, Lionel Tondji

The randomized extended Kaczmarz method is an effective iterative framework for solving large-scale inconsistent linear systems. In this paper, we extend this framework to third-or…

math.NA2026

Accelerated Exact Recovery from Noisy Data via Averaging and Noise-Aware Adaptive Bregman-Kaczmarz

Lionel Tondji, Abakar A. Mahamat, Idriss Tondji

The adaptive Bregman-Kaczmarz method recovers the exact, noise-free solution of a linear inverse problem even when every measurement it queries is corrupted, provided the corruptio…

math.NA2025

Why the noise model matters: A performance gap in learned regularization

Sebastian Banert, Christoph Brauer, Dirk Lorenz +1

This article addresses the challenge of learning effective regularizers for linear inverse problems. We analyze and compare several types of learned variational regularization agai…

math.OC2025★ 5 cited

An accelerated randomized Bregman-Kaczmarz method for strongly convex linearly constraint optimization

Lionel Tondji, Dirk A. Lorenz, Ion Necoara

In this paper, we propose a randomized accelerated method for the minimization of a strongly convex function under linear constraints. The method is of Kaczmarz-type, i.e. it only…

math.NA2023

Acceleration and restart for the randomized Bregman-Kaczmarz method

Lionel Tondji, Ion Necoara, Dirk A. Lorenz

Optimizing strongly convex functions subject to linear constraints is a fundamental problem with numerous applications. In this work, we propose a block (accelerated) randomized Br…

math.NA2023

Adaptive Bregman-Kaczmarz: An Approach to Solve Linear Inverse Problems with Independent Noise Exactly

Lionel Tondji, Idriss Tondji, Dirk A. Lorenz

We consider the block Bregman-Kaczmarz method for finite dimensional linear inverse problems. The block Bregman-Kaczmarz method uses blocks of the linear system and performs iterat…

math.NA2023

Linearly convergent adjoint free solution of least squares problems by random descent

Dirk A. Lorenz, Felix Schneppe, Lionel Tondji

We consider the problem of solving linear least squares problems in a framework where only evaluations of the linear map are possible. We derive randomized methods that do not need…

math.NA2022

Faster Randomized Block Sparse Kaczmarz by Averaging

Lionel Tondji, Dirk A Lorenz

The standard randomized sparse Kaczmarz (RSK) method is an algorithm to compute sparse solutions of linear systems of equations and uses sequential updates, and thus, does not take…

math.NA2022★ 1 cited

Extended Randomized Kaczmarz Method for Sparse Least Squares and Impulsive Noise Problems

Frank Schöpfer, Dirk A Lorenz, Lionel Tondji +1

The Extended Randomized Kaczmarz method is a well known iterative scheme which can find the Moore-Penrose inverse solution of a possibly inconsistent linear system and requires onl…

cs.LG2021

Variance Reduction in Deep Learning: More Momentum is All You Need

Lionel Tondji, Sergii Kashubin, Moustapha Cisse

Variance reduction (VR) techniques have contributed significantly to accelerating learning with massive datasets in the smooth and strongly convex setting (Schmidt et al., 2017; Jo…