5 papers
Determining the space dependent coefficients in space-time fractional diffusion equations via Krylov preconditioning
Asim Ilyas, Muhammad Faisal Khan, Rosita L. Sormani +2
We consider a time-space fractional diffusion equation with a variable coefficient and investigate the inverse problem of reconstructing the source term, after regularizing the pro…
Block triangular preconditioning for inverse source problems in time-space fractional diffusion equations
Monoswini Majumdar, Stefano Serra-Capizzano, Rosita L. Sormani
The current work investigates the effectiveness of block triangular preconditioners in accelerating and stabilizing the numerical solution of inverse source problems governed by ti…
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…
Symbol-based multilevel block preconditioners for multilevel block Toeplitz systems: GLT-based analysis and applications
Sean Y. Hon, Congcong Li, Rosita L. Sormani +2
In recent years, there has been a renewed interest in preconditioning for multilevel Toeplitz systems, a research field that has been extensively explored over the past several dec…
Asymptotic spectral properties and preconditioning of an approximated nonlocal Helmholtz equation with Caputo fractional Laplacian and variable coefficient wave number
Andrea Adriani, Rosita Luisa Sormani, Cristina Tablino-Possio +2
The current study investigates the asymptotic spectral properties of a finite difference approximation of nonlocal Helmholtz equations with a Caputo fractional Laplacian and a vari…