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Accession Number DE2012-1052181
Title Efficient Scalable Algorithms for Hierarchically Semiseparable Matrices.
Publication Date 2011
Media Count 22p
Personal Author J. Xia M. V. De Hoop S. Wang X. S. Li Y. Situ
Abstract Hierarchically semiseparable (HSS) matrix algorithms are emerging techniques in constructing the superfast direct solvers for both dense and sparse linear systems. Here, we developed a set of novel parallel algorithms for the key HSS operations that are used for solving large linear systems. These include the parallel rank-revealing QR factorization, the HSS constructions with hierarchical compression, the ULV HSS factorization, and the HSS solutions. The HSS tree based parallelism is fully exploited at the coarse level. The BLACS and ScaLAPACK libraries are used to facilitate the parallel dense kernel operations at the ne-grained level. We have appplied our new parallel HSS-embedded multifrontal solver to the anisotropic Helmholtz equations for seismic imaging, and were able to solve a linear system with 6.4 billion unknowns using 4096 processors, in about 20 minutes. The classical multifrontal solver simply failed due to high demand of memory. To our knowledge, this is the rst successful demonstration of employing the HSS algorithms in solving the truly large-scale real-world problems. Our parallel strategies can be easily adapted to the parallelization of the other rank structured methods.
Keywords Algorithms
Linear systems
Problem solving

Source Agency Technical Information Center Oak Ridge Tennessee
NTIS Subject Category 72B - Algebra, Analysis, Geometry, & Mathematical Logic
Corporate Author Lawrence Berkeley National Lab., CA.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1307
Contract Number N/A

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