A direct method to solve block banded block Toeplitz systems with non-banded Toeplitz blocks

  • Authors:
  • Andrey Chesnokov;Marc Van Barel

  • Affiliations:
  • Katholieke Universiteit Leuven, Department of Computer Science, Celestijnenlaan 200A, 3001 Heverlee, Belgium;Katholieke Universiteit Leuven, Department of Computer Science, Celestijnenlaan 200A, 3001 Heverlee, Belgium

  • Venue:
  • Journal of Computational and Applied Mathematics
  • Year:
  • 2010

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Abstract

A fast solution algorithm is proposed for solving block banded block Toeplitz systems with non-banded Toeplitz blocks. The algorithm constructs the circulant transformation of a given Toeplitz system and then by means of the Sherman-Morrison-Woodbury formula transforms its inverse to an inverse of the original matrix. The block circulant matrix with Toeplitz blocks is converted to a block diagonal matrix with Toeplitz blocks, and the resulting Toeplitz systems are solved by means of a fast Toeplitz solver. The computational complexity in the case one uses fast Toeplitz solvers is equal to @x(m,n,k)=O(mn^3)+O(k^3n^3) flops, there are m block rows and m block columns in the matrix, n is the order of blocks, 2k+1 is the bandwidth. The validity of the approach is illustrated by numerical experiments.