GenEO coarse spaces for heterogeneous indefinite elliptic problems

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Bootland, Niall and Dolean, Victorita and Graham, Ivan G. and Ma, Chupeng and Scheichl, Robert (2021) GenEO coarse spaces for heterogeneous indefinite elliptic problems. Preprint / Working Paper. arXiv.org, Ithaca, N.Y..

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Abstract

Motivated by recent work on coarse spaces for Helmholtz problems, we provide in this paper a comparative study on the use of spectral coarse spaces of GenEO type for heterogeneous indefinite elliptic problems within an additive overlapping Schwarz method. In particular, we focus here on two different but related formulations of local generalised eigenvalue problems and compare their performance numerically. Even though their behaviour seems to be very similar for several well-known heterogeneous test cases that are mildly indefinite, only one of the coarse spaces has so far been analysed theoretically, while the other one leads to a significantly more robust domain decomposition method when the indefiniteness is increased. We present a summary of recent results developing such a theory and describe how the numerical experiments illustrate it.

ORCID iDs

Bootland, Niall ORCID logoORCID: https://orcid.org/0000-0002-3207-5395, Dolean, Victorita ORCID logoORCID: https://orcid.org/0000-0002-5885-1903, Graham, Ivan G., Ma, Chupeng and Scheichl, Robert;
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