论文标题
自适应大量平行算法,用于切割问题
Adaptive Massively Parallel Algorithms for Cut Problems
论文作者
论文摘要
我们研究自适应大量平行计算(AMPC)模型中的加权最小切割问题。在2019年,Behnezhad等人。 [3]引入了AMPC模型作为大规模并行计算(MPC)模型的扩展。在过去的十年中,对高度可扩展算法的研究对许多大型系统产生了重大影响。 MPC模型,由Karloff等人于2010年推出。 [16]这是MapReduce,Hadoop,Flume和Spark等著名实践框架的抽象,一直处于这项研究的最前沿。尽管已经为针对一系列问题创建高效的MPC算法而取得了长足的进步,但最近的进度受到了1-VS-2周期猜想的限制[20],该猜想假定区分一个和两个周期之间的简单问题需要$ω(\ log log n)$ MPC回合。在AMPC模型中,每台机器都具有对分布式哈希表的自适应读取访问权限,即使限制了通信(即在回合的中间)。在保持实用[4]的同时,这使算法绕过绕过1-VS-2周期猜想的限制。 我们给出了第一个sublogarithmic AMPC算法,需要$ O(\ log \ log n)$ rounds,以$(2+ε)$ - 近似加权的最小剪切。我们的算法的灵感来自Ghaffari和Nowicki [11]的鸿沟和征服方法,该方法使用Karger和Stein的经典结果[15]解决了$(2+ε)$ - 近似加权的最小切割问题(\ log n \ log log \ log \ log \ log \ log \ log \ log \ log \ log \ log \ log \ log \ log n)$ rounds $。从任何常数$ 0 <ε<1 $的局部内存为$ O(n^ε)$的意义上,我们的工作是完全估计的。没有$ O(\ log n)$ - 圆形MPC算法在此内存制度中削减的最小值算法,假设有1-VS-2周期的猜想。 AMPC中的指数速度是解耦分隔和征服算法的不同层的结果,并在$ O(1)$ rounds中求解所有层。
We study the Weighted Min Cut problem in the Adaptive Massively Parallel Computation (AMPC) model. In 2019, Behnezhad et al. [3] introduced the AMPC model as an extension of the Massively Parallel Computation (MPC) model. In the past decade, research on highly scalable algorithms has had significant impact on many massive systems. The MPC model, introduced in 2010 by Karloff et al. [16], which is an abstraction of famous practical frameworks such as MapReduce, Hadoop, Flume, and Spark, has been at the forefront of this research. While great strides have been taken to create highly efficient MPC algorithms for a range of problems, recent progress has been limited by the 1-vs-2 Cycle Conjecture [20], which postulates that the simple problem of distinguishing between one and two cycles requires $Ω(\log n)$ MPC rounds. In the AMPC model, each machine has adaptive read access to a distributed hash table even when communication is restricted (i.e., in the middle of a round). While remaining practical [4], this gives algorithms the power to bypass limitations like the 1-vs-2 Cycle Conjecture. We give the first sublogarithmic AMPC algorithm, requiring $O(\log\log n)$ rounds, for $(2+ε)$-approximate weighted Min Cut. Our algorithm is inspired by the divide and conquer approach of Ghaffari and Nowicki [11], which solves the $(2+ε)$-approximate weighted Min Cut problem in $O(\log n\log\log n)$ rounds of MPC using the classic result of Karger and Stein [15]. Our work is fully-scalable in the sense that the local memory of each machine is $O(n^ε)$ for any constant $0 < ε< 1$. There are no $o(\log n)$-round MPC algorithms for Min Cut in this memory regime assuming the 1-vs-2 Cycle Conjecture holds. The exponential speedup in AMPC is the result of decoupling the different layers of the divide and conquer algorithm and solving all layers in $O(1)$ rounds.