Bloch, Jacques C. R. and Heybrock, Simon (2011) A nested Krylov subspace method to compute the sign function of large complex matrices. COMPUTER PHYSICS COMMUNICATIONS, 182 (4). pp. 878-889. ISSN 0010-4655,
Full text not available from this repository. (Request a copy)Abstract
We present an acceleration of the well-established Krylov-Ritz methods to compute the sign function of large complex matrices, as needed in lattice QCD simulations involving the overlap Dirac operator at both zero and nonzero baryon density. Krylov-Ritz methods approximate the sign function using a projection on a Krylov subspace. To achieve a high accuracy this subspace must be taken quite large, which makes the method too costly. The new idea is to make a further projection on an even smaller, nested Krylov subspace. If additionally an intermediate preconditioning step is applied, this projection can be performed without affecting the accuracy of the approximation, and a substantial gain in efficiency is achieved for both Hermitian and non-Hermitian matrices. The numerical efficiency of the method is demonstrated on lattice configurations of sizes ranging from 4(4) to 10(4), and the new results are compared with those obtained with rational approximation methods. (C) 2010 Elsevier B.V. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | OVERLAP DIRAC OPERATOR; LATTICE; Lattice QCD; Krylov methods; Chiral symmetry; Sign function |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Theroretical Physics |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 23 Jun 2020 07:13 |
| Last Modified: | 23 Jun 2020 07:14 |
| URI: | https://pred.uni-regensburg.de/id/eprint/21065 |
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