arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1707.08484cs.DCcs.DS
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O(1)轮拥塞团的MST

MST in O(1) Rounds of the Congested Clique

Tomasz Jurdzinski, Krzysztof Nowicki

摘要:

提出了一种在拥挤团模型中以高概率在O(1)轮内找到给定图的最小生成树(MST)的分布式随机算法。拥塞集团模型中的输入图是n个节点的图,其中每个节点最初仅知道其关联边。通信图是具有有限边缘带宽的团:每两个节点(不一定是输入图中的邻居)可以交换$O(\log n)$比特。在以前的作品中,MST算法的关键部分是一个有效的连接组件(CC)算法。然而,与以前的方法不同,我们的目标不是模拟标准的Boruvka算法,至少在CC算法的初始阶段。相反,我们开发了一种新的技术,它结合了样本稀疏子图的输入图的连接组件,以加快原始输入图的连接组件的发现过程。更具体地说,我们开发了一种稀疏化技术,减少了初始CC问题的$O(1)$轮,其两个限制的情况下。前一个实例有一个以最大度$O(\log \log n)$作为输入的图--这里我们的样本组合技术很有用。在后一种情况下,已知将输入图划分为$O(n/\log \log n)$连通分量。这提供了应用先前算法来确定$O(1)$轮中的连通分量的机会。我们的结果解决了Lotker等人[SPAA 2003; SICOMP 2005]的$O(\log \log n)$算法的问题,改进了Ghaffari等人[PODC 2016]的先前$O(\log* n)$算法和Hegeman等人[PODC 2015]的$O(\log \log \log n)$算法。它还确定$Θ(1)$轮复杂度在拥挤的团MST,以及其他图的问题,包括二分性,割验证,s-t连接和循环包含。

英文摘要:

We present a distributed randomized algorithm finding Minimum Spanning Tree (MST) of a given graph in O(1) rounds, with high probability, in the Congested Clique model. The input graph in the Congested Clique model is a graph of n nodes, where each node initially knows only its incident edges. The communication graph is a clique with limited edge bandwidth: each two nodes (not necessarily neighbours in the input graph) can exchange $O(\log n)$ bits. As in previous works, the key part of the MST algorithm is an efficient Connected Components (CC) algorithm. However, unlike the former approaches, we do not aim at simulating the standard Boruvka algorithm, at least at initial stages of the CC algorithm. Instead, we develop a new technique which combines connected components of sample sparse subgraphs of the input graph in order to accelerate the process of uncovering connected components of the original input graph. More specifically, we develop a sparsification technique which reduces an initial CC problem in $O(1)$ rounds to its two restricted instances. The former instance has a graph with maximal degree $O(\log \log n)$ as the input -- here our sample-combining technique helps. In the latter instance, a partition of the input graph into $O(n/\log \log n)$ connected components is known. This gives an opportunity to apply previous algorithms to determine connected components in $O(1)$ rounds. Our result addresses the problem from and the $O(\log \log n)$ algorithm of Lotker et al. [SPAA 2003; SICOMP 2005], improves over previous $O(\log* n)$ algorithm of Ghaffari et al. [PODC 2016] and $O(\log \log \log n)$ algorithm of Hegeman et al. [PODC 2015] . It also determines $Θ(1)$ round complexity in the congested clique for MST, as well as other graph problems, including bipartiteness, cut verification, s-t connectivity and cycle containment.

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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