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arXiv 2106.02685cs.DS
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大规模并行动态最小聚类算法

Massively Parallel and Dynamic Algorithms for Minimum Size Clustering

Alessandro Epasto, Mohammad Mahdian, Vahab Mirrokni, Peilin Zhong

摘要:

在本文中,我们研究了$r$ -聚集问题,一个自然制定的最小尺寸聚类度量空间。$r$ -聚集的目标是将$n$点划分为簇,使得每个簇的大小至少为$r$,并且簇的最大半径最小化。这个额外的约束完全改变了问题的算法性质,许多聚类技术都失败了。以前的动态和并行算法也没有达到理想的复杂度。我们提出的算法在大规模并行计算(MPC)模型和动态设置。我们的MPC算法处理来自欧几里德空间$\mathbb{R}^d$的输入点。对于任意小的常数$\varepsilon,γ> 0$,它使用全空间$O(n^{1+γ}\cdot d)$计算$r$-道集的$O(1)$-近似解。此外,我们的算法是完全可扩展的,即,每台机器的内存没有下限。我们的动态算法保持一个$O(1)$ -近似$r$ -收集的解决方案下插入/删除的点在一个度量空间的双倍维数$d$。更新时间是$r \cdot 2^{O(d)}\cdot \log^{O(1)}Δ$,查询时间是$2^{O(d)}\cdot \log^{O(1)}Δ$,其中$Δ$是最大距离和最小距离之间的比率。

英文摘要:

In this paper, we study the $r$-gather problem, a natural formulation of minimum-size clustering in metric spaces. The goal of $r$-gather is to partition $n$ points into clusters such that each cluster has size at least $r$, and the maximum radius of the clusters is minimized. This additional constraint completely changes the algorithmic nature of the problem, and many clustering techniques fail. Also previous dynamic and parallel algorithms do not achieve desirable complexity. We propose algorithms both in the Massively Parallel Computation (MPC) model and in the dynamic setting. Our MPC algorithm handles input points from the Euclidean space $\mathbb{R}^d$. It computes an $O(1)$-approximate solution of $r$-gather in $O(\log^{\varepsilon} n)$ rounds using total space $O(n^{1+γ}\cdot d)$ for arbitrarily small constants $\varepsilon,γ> 0$. In addition our algorithm is fully scalable, i.e., there is no lower bound on the memory per machine. Our dynamic algorithm maintains an $O(1)$-approximate $r$-gather solution under insertions/deletions of points in a metric space with doubling dimension $d$. The update time is $r \cdot 2^{O(d)}\cdot \log^{O(1)}Δ$ and the query time is $2^{O(d)}\cdot \log^{O(1)}Δ$, where $Δ$ is the ratio between the largest and the smallest distance.

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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