Abstract
This paper proposes a new approach for choosing the regularization parameters in multi-parameter regularization methods when applied to approximate the solution of linear discrete ill-posed problems. We consider both direct methods, such as Tikhonov regularization with two or more regularization terms, and iterative methods based on the projection of a Tikhonov-regularized problem onto Krylov subspaces of increasing dimension. The latter methods regularize by choosing appropriate regularization terms and the dimension of the Krylov subspace. Our investigation focuses on selecting a proper set of regularization parameters that satisfies the discrepancy principle and maximizes a suitable quantity, whose size reflects the quality of the computed approximate solution. Theoretical results are shown and illustrated by numerical experiments.
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Acknowledgments
We are grateful to Giuseppe Rodriguez for providing us with the GCV-based multi-parameter regularization software, as well as to the editor and referees for remarks that lead to improvements of the presentation.
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Communicated by Rosemary Renaut.
Research supported in part by the GNCS project “Giovani Ricercatori”, by the “ex-60 %” funds of the University of Padova, and by NSF Grant DMS-1115385.
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Gazzola, S., Reichel, L. A new framework for multi-parameter regularization. Bit Numer Math 56, 919–949 (2016). https://doi.org/10.1007/s10543-015-0595-4
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DOI: https://doi.org/10.1007/s10543-015-0595-4