10 papers
Communication Lower Bounds and Algorithms for Sketching with Random Dense Matrices
Hussam Al Daas, Grey Ballard, Laura Grigori +4
Sketching is widely used in randomized linear algebra for low-rank matrix approximation, column subset selection, and many other problems, and it has gained significant traction in…
Two-level convergence of Algebraic Multigrid with Overlapping Smoothers and Spectral Coarse Grids
O. A. Krzysik, B. S. Southworth, H. Al Daas
We recently developed the least-squares algebraic-multigrid domain-decomposition (LS-AMG-DD) solver as an algebraic multilevel method for sparse symmetric positive definite matrice…
Efficient Sketching-Based Summation of Tucker Tensors
Rudi Smith, Mirjeta Pasha, Andrés Galindo-Olarte +5
We present efficient, sketching-based methods for the summation of tensors in Tucker format. Leveraging the algebraic structure of Khatri-Rao and Kronecker products, our approach e…
Extended-Krylov-subspace methods for trust-region and norm-regularization subproblems
Hussam Al Daas, Nicholas I. M. Gould
We consider an effective new method for solving trust-region and norm-regularization problems that arise as subproblems in many optimization applications. We show that the solution…
Reducing acquisition time and radiation damage: data-driven subsampling for spectro-microscopy
Maike Meier, Lorenzo Lazzarino, Boris Shustin +2
Spectro-microscopy is an experimental technique which can be used to observe spatial variations in chemical state and changes in chemical state over time or under experimental cond…
Minimal residual rational Krylov subspace method for sequences of shifted linear systems
Hussam Al Daas, Davide Palitta
The solution of sequences of shifted linear systems is a classic problem in numerical linear algebra, and a variety of efficient methods have been proposed over the years. Neverthe…