83 citations · 130 across the 28 of their papers we have counts for
9 papers · 1 filter
A Unified Framework for Randomized Row-Action Methods for Structured Data Fitting and Constraint Geometry
Valentin Leplat, Zeyu Dong, Junfeng Yin
We study randomized row-action methods for problems with linear observations, convex constraints, and non-Euclidean geometry. Our starting point is a unified formulation in which t…
Iterative Methods for Computing the Moore--Penrose Inverse of Split-Quaternion Matrices with Applications
Salman Ahmadi-Asl, Valentin Leplat, Mohammad S. Alkousa
We study iterative methods for computing the Moore--Penrose inverse of split-quaternion matrices. We first establish a consistent framework based on a \(2\times2\) real representat…
Quaternion Maximum-Volume Submatrix Selection with Applications to Multichannel Imaging and Visual Data
Vsevolod Kliushev, Junjun Pan, Valentin Leplat
Low-rank approximation based on selected rows and columns is a useful alternative to singular value decompositions when the goal is an interpretable and compact matrix representati…
Adaptive Randomized Pivoting for Tensor Cross Approximation in the T-Product Framework
Ahmadsho Akdodshoev, Valentin Leplat, Salman Ahmadi-Asl
This paper studies extensions of adaptive randomized pivoting (ARP), recently introduced for matrix column subset selection, to tensors in the t-product framework. We propose two c…
Prox-NAG-GS: A Semi-Implicit Proximal Method for Composite Optimization
Sikeh Gisele Wiykiynyuy, Kelvin Asu Ekuri, Valentin Leplat
Composite optimization problems, where a smooth loss is combined with a nonsmooth regularizer, are common in machine learning and inverse problems. In this work, we study a proxima…
IRON: Implicit Resolvent Optimization under Noise
Valentin Leplat, Roland Hildebrand
We study stochastic optimization from a joint continuous-discrete point of view. Starting from a second-order stochastic differential equation interpreted as a noisy accelerated gr…
QuatIca: Advanced Numerical Linear Algebra and Optimization for Quaternionic Matrices in Python
Valentin Leplat, Salman Ahmadi-Asl, Junjun Pan +2
Quaternion-valued representations provide a convenient way to model coupled multi-channel signals (e.g., RGB imagery, polarization data, vector fields, and multi-detector time seri…
A New Tensor Network: Tubal Tensor Train and Its Applications
Salman Ahmadi-Asl, Valentin Leplat, Anh-Huy Phan +1
We introduce the tubal tensor train (TTT) decomposition, a tensor-network model that combines the t-product algebra of the tensor singular value decomposition (T-SVD) with the low-…
Joint Majorization-Minimization for Nonnegative CP and Tucker Decompositions under -Divergences: Unfolding-Free Updates
Valentin Leplat
We study majorization-minimization methods for nonnegative tensor decompositions under the -divergence family, focusing on nonnegative CP and Tucker models. Our aim is to avoid…