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001     50021
005     20180211180142.0
024 7 _ |2 DOI
|a 10.1016/j.cpc.2004.10.005
024 7 _ |2 WOS
|a WOS:000226893500003
037 _ _ |a PreJuSER-50021
041 _ _ |a eng
082 _ _ |a 004
084 _ _ |2 WoS
|a Computer Science, Interdisciplinary Applications
084 _ _ |2 WoS
|a Physics, Mathematical
100 1 _ |a Cundy, N.
|b 0
|0 P:(DE-HGF)0
245 _ _ |a Numerical Methods for the QCD Overlap Operator. III. Nested Iterations
260 _ _ |a Amsterdam
|b North Holland Publ. Co.
|c 2005
300 _ _ |a 221 - 242
336 7 _ |a Journal Article
|0 PUB:(DE-HGF)16
|2 PUB:(DE-HGF)
336 7 _ |a Output Types/Journal article
|2 DataCite
336 7 _ |a Journal Article
|0 0
|2 EndNote
336 7 _ |a ARTICLE
|2 BibTeX
336 7 _ |a JOURNAL_ARTICLE
|2 ORCID
336 7 _ |a article
|2 DRIVER
440 _ 0 |a Computer Physics Communications
|x 0010-4655
|0 1439
|v 165
500 _ _ |a Record converted from VDB: 12.11.2012
520 _ _ |a The numerical and computational aspects of chiral fermions in lattice quantum chromodynamics are extremely demanding. In the overlap framework, the computation of the fermion propagator leads to a nested iteration where the matrix vector multiplications in each step of an outer iteration have to be accomplished by an inner iteration; the latter approximates the product of the sign function of the hermitian Wilson fermion matrix with a vector.In this paper we investigate aspects of this nested paradigm. We examine several Krylov subspace methods to be used as an outer iteration for both propagator computations and the Hybrid Monte-Carlo scheme. We establish criteria on the accuracy of the inner iteration which allow to preserve an a priori given precision for the overall computation. It will turn out that the accuracy of the sign function can be relaxed as the outer iteration proceeds. Furthermore, we consider preconditioning strategies, where the preconditioner is built upon an inaccurate approximation to the sign function. Relaxation combined with preconditioning allows for considerable savings in computational efforts up to a factor of 4 as our numerical experiments illustrate. We also discuss the possibility of projecting the squared overlap operator into one chiral sector. (C) 2004 Elsevier B.V. All rights reserved.
536 _ _ |a Betrieb und Weiterentwicklung des Höchstleistungsrechners
|c I03
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588 _ _ |a Dataset connected to Web of Science
650 _ 7 |a J
|2 WoSType
653 2 0 |2 Author
|a lattice quantum chromodynamics
653 2 0 |2 Author
|a overlap fermions
653 2 0 |2 Author
|a matrix sign function
653 2 0 |2 Author
|a inner-outer iterations
653 2 0 |2 Author
|a relaxation
653 2 0 |2 Author
|a flexible Krylov
653 2 0 |2 Author
|a subspace methods
700 1 _ |a Eshof v. d., J.
|b 1
|0 P:(DE-HGF)0
700 1 _ |a Frommer, A.
|b 2
|0 P:(DE-HGF)0
700 1 _ |a Krieg, S.
|b 3
|u FZJ
|0 P:(DE-Juel1)132171
700 1 _ |a Lippert, T.
|b 4
|u FZJ
|0 P:(DE-Juel1)132179
700 1 _ |a Schäfer, K.
|b 5
|0 P:(DE-HGF)0
773 _ _ |a 10.1016/j.cpc.2004.10.005
|g Vol. 165, p. 221 - 242
|p 221 - 242
|q 165<221 - 242
|0 PERI:(DE-600)1466511-6
|t Computer physics communications
|v 165
|y 2005
|x 0010-4655
856 7 _ |u http://dx.doi.org/10.1016/j.cpc.2004.10.005
909 C O |o oai:juser.fz-juelich.de:50021
|p VDB
913 1 _ |k I03
|v Betrieb und Weiterentwicklung des Höchstleistungsrechners
|l Wissenschaftliches Rechnen
|b Information
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|x 0
914 1 _ |y 2005
915 _ _ |0 StatID:(DE-HGF)0010
|a JCR/ISI refereed
920 1 _ |k ZAM
|l Zentralinstitut für Angewandte Mathematik
|d 31.12.2007
|g ZAM
|0 I:(DE-Juel1)VDB62
|x 0
970 _ _ |a VDB:(DE-Juel1)78203
980 _ _ |a VDB
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980 _ _ |a journal
980 _ _ |a I:(DE-Juel1)JSC-20090406
980 _ _ |a UNRESTRICTED
981 _ _ |a I:(DE-Juel1)JSC-20090406

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