Analysis of preconditioning techniques for ill-conditioned Toeplitz matrices
SIAM Journal on Scientific Computing
SIAM Journal on Scientific Computing
Conjugate Gradient Methods for Toeplitz Systems
SIAM Review
Any Circulant-Like Preconditioner for Multilevel Matrices Is Not Superlinear
SIAM Journal on Matrix Analysis and Applications
Preconditioners for Ill-Conditioned Toeplitz Systems Constructed from Positive Kernels
SIAM Journal on Scientific Computing
New Band Toeplitz Preconditioners for Ill-Conditioned Symmetric Positive Definite Toeplitz Systems
SIAM Journal on Matrix Analysis and Applications
How to prove that a preconditioner cannot be superlinear
Mathematics of Computation
Theoretical Computer Science - Algebraic and numerical algorithm
Superlinear convergence for PCG using band plus algebra preconditioners for Toeplitz systems
Computers & Mathematics with Applications
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In the last two decades a lot of matrix algebra optimal and suxper-linear preconditioners (those assuring a strong clustering at the unity) have been proposed for the solution of polynomially ill-conditioned Toeplitz linear systems. The corresponding generalizations to multilevel structures do not preserve optimality neither superlinearity (see e.g. [11]). Regarding the notion of superlinearity, it has been recently shown that this is simply impossible (see [15, 17, 18]). Here we propose some ideas and a proof technique for demonstrating that also the spectral equivalence and the essential spectral equivalence (up to a constant number of diverging eigenvalues) are impossible and therefore the search for optimal matrix algebra preconditioners in the multilevel setting cannot be successful.