arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0808.2664math.NAcs.NA
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通信最优的并行和顺序QR与LU分解

Communication-optimal parallel and sequential QR and LU factorizations

James Demmel, Laura Grigori, Mark Hoemmen, Julien Langou

AI总结:

提出通信量最优(至多对数因子)且与Householder QR同样稳定的并行和顺序稠密QR分解算法,并证明现有LAPACK和ScaLAPACK算法通信量渐近更大。

摘要:

我们提出了并行和顺序稠密QR分解算法,这些算法在通信量上是最优的(至多对数因子),并且与Householder QR同样稳定。我们通过扩展已知的顺序和并行矩阵乘法的通信带宽下界来提供延迟下界,并证明这些下界适用于LU和QR分解。我们不仅证明了我们的QR算法达到了这些下界(至多对数因子),而且现有的LAPACK和ScaLAPACK算法执行的通信量渐近更大。我们还指出了文献中最近的LU算法至少达到了这些下界中的一部分。

英文摘要:

We present parallel and sequential dense QR factorization algorithms that are both optimal (up to polylogarithmic factors) in the amount of communication they perform, and just as stable as Householder QR. We prove optimality by extending known lower bounds on communication bandwidth for sequential and parallel matrix multiplication to provide latency lower bounds, and show these bounds apply to the LU and QR decompositions. We not only show that our QR algorithms attain these lower bounds (up to polylogarithmic factors), but that existing LAPACK and ScaLAPACK algorithms perform asymptotically more communication. We also point out recent LU algorithms in the literature that attain at least some of these lower bounds.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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