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arXiv 1905.04897cs.DS
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流算法用于装箱和向量调度

Streaming Algorithms for Bin Packing and Vector Scheduling

Department of Computer Science, University of Warwick(华威大学计算机科学系)

Graham Cormode, Pavel Veselý

AI总结:

本文提出高效的流算法解决装箱和向量调度问题,实现近似最优解并优化空间复杂度。

摘要:

涉及简单对象高效排列的问题,如装箱和完成时间调度,是组合优化中的基本任务。这些在传统在线和离线情况下已得到充分理解,但在输入量真正巨大,甚至无法读入内存时,研究较少。这通过流计算模型来捕捉,其目标是在数据的一次遍历中,使用小空间近似解的成本。因此,流算法产生简洁的输入摘要,近似保留最优值。我们为这些基本的组合优化问题设计了首个高效的流算法。对于装箱问题,我们提供了一个流渐近1+ε近似算法,空间为O(1/ε),其中O隐藏了对数因子。此外,这样的空间界限本质上是最佳的。我们的算法表明,可以在d维中运行空间O(d/ε)的流d+ε近似算法用于向量装箱问题。对于相关的向量调度问题,我们展示了如何在空间O(d²·m/ε²)中构造输入摘要,保留最优值的因子为2-1/m+ε,其中m是相同机器的数量。

英文摘要:

Problems involving the efficient arrangement of simple objects, as captured by bin packing and makespan scheduling, are fundamental tasks in combinatorial optimization. These are well understood in the traditional online and offline cases, but have been less well-studied when the volume of the input is truly massive, and cannot even be read into memory. This is captured by the streaming model of computation, where the aim is to approximate the cost of the solution in one pass over the data, using small space. As a result, streaming algorithms produce concise input summaries that approximately preserve the optimum value. We design the first efficient streaming algorithms for these fundamental problems in combinatorial optimization. For Bin Packing, we provide a streaming asymptotic $1+\varepsilon$-approximation with $\widetilde{O}\left(\frac{1}{\varepsilon}\right)$ memory, where $\widetilde{O}$ hides logarithmic factors. Moreover, such a space bound is essentially optimal. Our algorithm implies a streaming $d+\varepsilon$-approximation for Vector Bin Packing in $d$ dimensions, running in space $\widetilde{O}\left(\frac{d}{\varepsilon}\right)$. For the related Vector Scheduling problem, we show how to construct an input summary in space $\widetilde{O}(d^2\cdot m / \varepsilon^2)$ that preserves the optimum value up to a factor of $2 - \frac{1}{m} +\varepsilon$, where $m$ is the number of identical machines.

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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