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An efficient multicore implementation of a novel HSS-structured multifrontal solver using randomized sampling. (English) Zbl 1352.65092
Summary: We present a sparse linear system solver that is based on a multifrontal variant of Gaussian elimination and exploits low-rank approximation of the resulting dense frontal matrices. We use hierarchically semiseparable (HSS) matrices, which have low-rank off-diagonal blocks, to approximate the frontal matrices. For HSS matrix construction, a randomized sampling algorithm is used together with interpolative decompositions. The combination of the randomized compression with a fast ULV HSS factorization leads to a solver with lower computational complexity than the standard multifrontal method for many applications, resulting in speedups up to sevenfold for problems in our test suite. The implementation targets many-core systems by using task parallelism with dynamic runtime scheduling. Numerical experiments show performance improvements over state-of-the-art sparse direct solvers. The implementation achieves high performance and good scalability on a range of modern shared memory parallel systems, including the Intel Xeon Phi (MIC). The code is part of a software package called STRUMPACK (STRUctured Matrices PACKage), which also has a distributed memory component for dense rank-structured matrices.
Reviewer: Reviewer (Berlin)

##### MSC:
 65F05 Direct numerical methods for linear systems and matrix inversion 65F50 Computational methods for sparse matrices 65Y05 Parallel numerical computation 65Y20 Complexity and performance of numerical algorithms
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##### References:
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