Publications, preprints & theses

Publications

[p20] Manuel Bogoya, Sven-Erik Ekström, Stefano Serra-Capizzano, and Paris Vassalos, Matrix-less methods for the spectral approximation of large non-Hermitian Toeplitz matrices: A concise theoretical analysis and a numerical study , Numerical Linear Algebra with Applications, (in press, 2024) (link, pdf)
[p19] Armando Coco, Sven-Erik Ekström, Giovanni Russo, Stefano Serra-Capizzano, and Santina Chiara Stissi, Spectral and norm estimates for matrix sequences arising from a finite difference approximation of elliptic operators , Linear Algebra and its Applications, 667, pp. 10-43 (2023) (link, pdf)
[p18] Matthias Bolten, Sven-Erik Ekström, Isabella Furci, and Stefano Serra-Capizzano A note on the spectral analysis of matrix sequences via GLT momentary symbols: from all-at-once solution of parabolic problems to distributed fractional order matrices , Electronic Transactions on Numerical Analysis, 58, pp. 136-163 (2023) (link, pdf)
[p17] Matthias Bolten, Sven-Erik Ekström, Isabella Furci, and Stefano Serra-Capizzano Toeplitz Momentary Symbols: definition, results, and limitations in the spectral analysis of Structured Matrices , Linear Algebra and Its Applications, 651, pp. 51-82 (2022) (link, pdf)
[p16] Manuel Bogoya, Sven-Erik Ekström, and Stefano Serra-Capizzano, Fast Toeplitz eigenvalue computations, joining interpolation-extrapolation matrix-less algorithms and simple-loop theory , Numerical Algorithms, 91, pp. 1653-1676 (2022) (link, pdf)
[p15] Nikos Barakitis, Sven-Erik Ekström, and Paris Vassalos, Preconditioners for Fractional Diffusion Equations Based on the Spectral Symbol Numercial Linear Algebra with Applications, 29(5), pp. e2441 (2022) (link, pdf)
[p14] Sven-Erik Ekström and Paris Vassalos, A Matrix-Less Method to Approximate the Spectrum and the Spectral Function of Toeplitz Matrices with Real Eigenvalues, Numerical Algorithms, 89, pp. 701-720 (2022) (link, pdf)
[p13] Sven-Erik Ekström, Carlo Garoni, Adam Jozefiak, and Jesse Perla, Eigenvalues and Eigenvectors of Tau Matrices with Applications to Markov Processes and Economics, Linear Algebra and Its Applications, 627, pp. 41-71 (2021) (link, pdf)
[p12] Minghua Chen, Sven-Erik Ekström, and Stefano Serra-Capizzano A Multigrid method for nonlocal problems: non-diagonally dominant Toeplitz-plus-tridiagonal systems, SIAM Journal on Matrix Analysis and Applications, 41(4), pp. 1546–1570 (2020) (link, pdf)
[p11] Sven-Erik Ekström and Stefano Serra-Capizzano, Eigenvalue isogeometric approximations based on B-splines: tools and results, pp. 57-76. In: Carlotta Giannelli, Hendrik Speleers (editors), Advanced Methods for Geometric Modeling and Numerical Simulation, Springer INdAM Series, vol 35, Springer, 2019 (link, pdf)
[p10] Carlo Garoni, Hendrik Speleers, Sven-Erik Ekström, Thomas J. R. Hughes, Alessandro Reali, and Stefano Serra-Capizzano,Finite element and isogeometric B-spline discretizations of eigenvalue problems: symbol-based analysis, Archives of Computational Methods in Engineering, 26(5), pp. 1639-1690 (2019) (link, pdf)
[p9] Sven-Erik Ekström and Carlo Garoni, A matrix-less and parallel interpolation-extrapolation algorithm for computing the eigenvalues of preconditioned banded symmetric Toeplitz matrices, Numerical Algorithms, 80(3), pp. 819-848 (2019) (link, pdf)
[p8] Sven-Erik Ekström, Isabella Furci, and Stefano Serra-Capizzano, Exact formulae and matrix-less eigensolvers for block banded symmetric Toeplitz matrices, BIT Numerical Mathematics, 58(4), pp. 937-968 (2018) (link, pdf)
[p7] Sven-Erik Ekström, Isabella Furci, Carlo Garoni, Carla Manni, Stefano Serra-Capizzano, and Hendrik Speleers, Are the eigenvalues of the B-spline isogeometric analysis approximation of -Δu=λu known in almost closed form?, Numerical Linear Algebra with Applications, 25(5), pp. e2198 (2018) (link, pdf)
[p6] Sven-Erik Ekström and Stefano Serra-Capizzano Eigenvalues and eigenvectors of banded Toeplitz matrices and the related symbols, Numerical Linear Algebra with Applications, 25(5), pp. e2137 (2018) (link, pdf, Letter to the editor, Reply to letter to the editor (pdf))
[p5] Fayyaz Ahmad, Eman Salem Al-Aidarous, Dina Abdullah Alrehaili, Sven-Erik Ekström, Isabella Furci, and Stefano Serra-Capizzano, Are the eigenvalues of preconditioned banded symmetric Toeplitz matrices known in almost closed form?, Numerical Algorithms, 78(3), pp. 867-893 (2018) (link, pdf)
[p4] Sven-Erik Ekström, Carlo Garoni, and Stefano Serra-Capizzano, Are the Eigenvalues of Banded Symmetric Toeplitz Matrices Known in Almost Closed Form?, Experimental Mathematics, 27(4), pp. 478-487 (2018) (link, pdf)
[p3] Sven-Erik Ekström and Martin Berggren, Agglomeration Multigrid for the Vertex-Centered Dual Discontinuous Galerkin Method, pp. 301-308. In: Norbert Kroll, Heribert Bieler, Herman Deconinck, Vincent Couaillier, Harmen Ven, Kaare Sörensen (editors) ADIGMA - A European Initiative on the Development of Adaptive Higher-Order Variational Methods for Aerospace Applications, Notes on Numerical Fluid Mechanics and Multidisciplinary Design, vol 113, Springer, 2010 (link, pdf)
[p2] Sven-Erik Ekström and Martin Berggren, Incorporating a Discontinuous Galerkin Method into the Existing Vertex-Centered Edge-Based Finite Volume Solver Edge, pp. 39-52. In: Norbert Kroll, Heribert Bieler, Herman Deconinck, Vincent Couaillier, Harmen Ven, Kaare Sörensen (editors) ADIGMA - A European Initiative on the Development of Adaptive Higher-Order Variational Methods for Aerospace Applications, Notes on Numerical Fluid Mechanics and Multidisciplinary Design, vol 113, Springer, 2010 (link, pdf)
[p1] Martin Berggren, Sven-Erik Ekström, and Jan Nordström, A Discontinuous Galerkin Extension of the Vertex-Centered Edge-Based Finite Volume Method, Communications in Computational Physics, 5(2-4), pp. 456-468 (2009) (link, pdf)

Preprints

[pr6] Giovanni Barbarino, Sven-Erik Ekström, Carlo Garoni, David Meadon, Stefano Serra-Capizzano, and Paris Vassalos Spectral properties of flipped Toeplitz matrices arXiv:2312.06170
[pr5] Giovanni Barbarino, Sven-Erik Ekström, Carlo Garoni, David Meadon, Stefano Serra-Capizzano, and Paris VassalosFrom asymptotic distribution and vague convergence to uniform convergence, with numerical applications arXiv:2309.03662
[pr4] Sven-Erik Ekström, and David Meadon On the eigenvalues of Toeplitz matrices with two off-diagonals arXiv:2305.15107
[pr3] Giovanni Barbarino, Sven-Erik Ekström, Stefano Serra-Capizzano, and Paris Vassalos Theoretical results for eigenvalues, singular values, and eigenvectors of (flipped) Toeplitz matrices and related computational proposals arXiv:2203.06992
[pr2] Giovanni Barbarino, Melker Claesson, Sven-Erik Ekström, Carlo Garoni, David Meadon, and Hendrik Speleers, Matrix-Less Eigensolver for Large Structured Matrices Technical Report 2021-007
[pr1] Sven-Erik Ekström, Approximating the Perfect Sampling Grids for Computing the Eigenvalues of Toeplitz-like Matrices Using the Spectral Symbol arXiv:1901.06917

Theses

[Ph.D.] Sven-Erik Ekström, Matrix-Less Methods for Computing Eigenvalues of Large Structured Matrices Uppsala University (2018) (link, full text)
Advisors: Maya Neytcheva, Stefano Serra-Capizzano, and Carlo Garoni.
[Tekn.Lic.] Sven-Erik Ekström, A Vertex-Centered Discontinuous Galerkin Method for Flow Problems Uppsala University (2016) (link)
Advisors: Martin Berggren and Per Lötstedt (and Jan Nordström and Axel Målqvist).