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arXiv 1708.09398cs.DScs.CCcs.SCmath.RT
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Strassen算法的设计

Designing Strassen's algorithm

Joshua A. Grochow, Cristopher Moore

摘要:

1969年,Strassen震惊了世界,他证明了两个n × n矩阵的相乘时间可以渐近地小于$O(n^3)$。虽然他的算法中的递归构造非常清楚,但关键的增益是通过显示2 x 2矩阵乘法可以仅用7次乘法而不是8次来执行。后一种结构是通过排除过程得出的,似乎是凭空产生的。在这里,我们给出了我们所知道的Strassen算法的最简单和最透明的证明,只使用一个简单的酉2-设计和几行简单的计算。此外,使用有限群表示论的基本事实,我们使用来自群轨道的2-设计将我们的构造推广到所有n(尽管所得算法对于n至少为3不是最优的)。

英文摘要:

In 1969, Strassen shocked the world by showing that two n x n matrices could be multiplied in time asymptotically less than $O(n^3)$. While the recursive construction in his algorithm is very clear, the key gain was made by showing that 2 x 2 matrix multiplication could be performed with only 7 multiplications instead of 8. The latter construction was arrived at by a process of elimination and appears to come out of thin air. Here, we give the simplest and most transparent proof of Strassen's algorithm that we are aware of, using only a simple unitary 2-design and a few easy lines of calculation. Moreover, using basic facts from the representation theory of finite groups, we use 2-designs coming from group orbits to generalize our construction to all n (although the resulting algorithms aren't optimal for n at least 3).

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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