26 citations · 26 across the 5 of their papers we have counts for
5 papers
Blocking structures, approximation, and preconditioning
Nikos Barakitis, Marco Donatelli, Samuele Ferri +3
We consider block-structured matrices , where the blocks are of (block) unilevel Toeplitz type with matrix-valued generating functions. Under mild assumptions on t…
A note on eigenvalues and singular values of variable Toeplitz matrices and matrix-sequences, with application to variable two-step BDF approximations to parabolic equations
Nikos Barakitis, Valerio Loi, Stefano Serra-Capizzano
Here, we consider a more general class of matrix-sequences and we prove that they belong to the maximal -algebra of generalized locally Toeplitz (GLT) matrix-sequences. Then, we…
Spectral Analysis and Preconditioned Iterative Solvers for Large Structured Linear Systems
Nikos Barakitis
In this thesis, the numerical solution of three different classes of problems have been studied. Specifically, new techniques have been proposed and their theoretical analysis has…
On a Boundary Updating Method for the Scalar Stefan Problem
Evangelos F. Magirou, Paraskevas Vassalos, Nikolaos Barakitis
We report on a general purpose method for the scalar Stefan problem inspired by the standard boundary updating method used in several existence proofs. By suitably modifying it we…
Preconditioners for Fractional Diffusion Equations Based on the Spectral Symbol
Nikos Barakitis, Sven-Erik Ekström, Paris Vassalos
It is well known that the discretization of fractional diffusion equations (FDEs) with fractional derivatives , using the so-called weighted and shifted Grünwald formula…