A family of modified regularizingcirculant preconditioners for two-levels Toeplitz systems

  • Authors:
  • D. A. Bini;P. Favati;O. Menchi

  • Affiliations:
  • -;-;-

  • Venue:
  • Computers & Mathematics with Applications
  • Year:
  • 2004

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Abstract

Customary circulant preconditioners of Chan, Strang, and inverse-Toeplitz type aremodified for the regularized solution of ill-conditioned Toeplitz systems. Given a symmetric two-level Toeplitz matrix A, and two parameters @t and @s, consider the customary preconditioner C and modify it by replacing its eigenvalues with modulus less than @t with the value @s. The circulant matrix obtained in this way is used as a preconditioner. We analyze the distribution of the eigenvalues of the preconditioned matrix and the regularization properties. Numerical experiments, shown for the image restoration problem, validate the theoretical results.