1996
DOI: 10.1007/bf01740547
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A preconditioner for constrained and weighted least squares problems with Toeplitz structure

Abstract: .We study methods for solving the constrained and weighted least squares problem minim a (b -Ax) T W (b -Ax) by the preconditioned conjugate gradient (PCG) method . k. It is well-known that this problem can be solved by solving an augmented linear 2 x 2 block linear system MA +Ax = b, AT A = 0, where M = W -1 . We will use the PCG method with circulant-like preconditioner for solving the system . We show that the spectrum of the preconditioned matrix is clustered around one . When the PCG method is applied to … Show more

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Cited by 9 publications
(5 citation statements)
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References 11 publications
(16 reference statements)
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“…Some of the algorithms considered in this paper are also applicable if one or more of the blocks in A happen to be dense, as long as matrixvector products with A can be performed efficiently, typically in O(n + m) time. This means that if a dense block is present, it must have a special structure (e.g., Toeplitz, as in Benzi and Ng (2004) and Jin (1996)) or it must be possible to approximate its action on a vector with (nearly) linear complexity, as in the fast multipole method (Mahawar and Sarin 2003).…”
Section: Sparsity Structure and Sizementioning
confidence: 99%
“…Some of the algorithms considered in this paper are also applicable if one or more of the blocks in A happen to be dense, as long as matrixvector products with A can be performed efficiently, typically in O(n + m) time. This means that if a dense block is present, it must have a special structure (e.g., Toeplitz, as in Benzi and Ng (2004) and Jin (1996)) or it must be possible to approximate its action on a vector with (nearly) linear complexity, as in the fast multipole method (Mahawar and Sarin 2003).…”
Section: Sparsity Structure and Sizementioning
confidence: 99%
“…Thus, this preconditioner is well defined even when some of the entries on the diagonal of W are zero. We note that this case does indeed arise in many situations of practical interest [9,20]. The scalar 1/(2α) in (3.3) has no impact on the preconditioned system…”
Section: Hermitian and Skew-hermitian Preconditioningmentioning
confidence: 86%
“…However, such a preconditioner is not easy to obtain, and it is too expensive. One possible choice is to approximate D by a circulant matrix C D ; see [20]. It is clear that the 1 For any square matrix A, consider the matrix operator…”
Section: Introductionmentioning
confidence: 99%
“…One alternative is to solve them directly by exploiting the matrix structure (see for example [6,16,47,73]). A more popular approach is to employ some iterative method to solve the system, assisted by an appropriately designed preconditioner, to ensure that the iterative method achieves fast convergence (as in [8,9,10,11,12,13,14,15,42,44,45,46,56,71]). An equally rich literature exists for preconditioning Toeplitz-like linear systems arising specifically from the discretization of fractional diffusion equations (see [17,24,25,29,32,45,46,48,53], among others).…”
Section: The Fde-constrained Optimization Modelmentioning
confidence: 99%