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arXiv 2102.08327cs.DScs.LG
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背包约束下的次模最大化:具有近最优自适应复杂度的组合算法

Submodular Maximization subject to a Knapsack Constraint: Combinatorial Algorithms with Near-optimal Adaptive Complexity

University of Essex(埃塞克斯大学);Athena Research Center(雅典娜研究中心);Sapienza University of Rome(罗马第一大学);Input Output;University of Amsterdam(阿姆斯特丹大学)

Georgios Amanatidis, Federico Fusco, Philip Lazos, Stefano Leonardi, Alberto Marchetti Spaccamela, Rebecca Reiffenhäuser

AI总结:

本文针对背包约束下的非单调次模最大化问题,提出了首个具有近最优 $O(\log n)$ 自适应复杂度的常数因子近似组合算法,并可通过 $\tilde{O}(n)$ 次值查询保持低自适应复杂度。

摘要:

次模最大化是一个经典的算法问题,在数据挖掘和机器学习中有多种应用;在这些领域,处理大规模实例的需求不断增长,促使人们设计平衡解质量与适用性的算法。对于后者,一个重要的衡量标准是自适应复杂度,它刻画了算法终止所需的并行计算的顺序轮数。在本文中,我们针对背包约束下的非单调次模最大化问题,获得了首个具有近最优 $O(\log n)$ 自适应复杂度的常数因子近似算法。然而,仅凭低自适应度是不够的:一个需要考虑的关键特征是函数求值(或值查询)的总数。我们的算法需要 $\tilde{O}(n^2)$ 次值查询,但可以修改为仅需 $\tilde{O}(n)$ 次查询运行,同时保持 $O(\log^2n)$ 的低自适应复杂度。除了上述自适应性的改进外,这也是该问题首个具有次线性自适应复杂度的组合方法,并且即使在基数约束或单调目标等特殊情况下,其算法也与现有技术水平相当。

英文摘要:

Submodular maximization is a classic algorithmic problem with multiple applications in data mining and machine learning; there, the growing need to deal with massive instances motivates the design of algorithms balancing the quality of the solution with applicability. For the latter, an important measure is the adaptive complexity, which captures the number of sequential rounds of parallel computation needed by an algorithm to terminate. In this work we obtain the first constant factor approximation algorithm for non-monotone submodular maximization subject to a knapsack constraint with near-optimal $O(\log n)$ adaptive complexity. Low adaptivity by itself, however, is not enough: a crucial feature to account for is represented by the total number of function evaluations (or value queries). Our algorithm asks $\tilde{O}(n^2)$ value queries, but can be modified to run with only $\tilde{O}(n)$ instead, while retaining a low adaptive complexity of $O(\log^2n)$. Besides the above improvement in adaptivity, this is also the first combinatorial approach with sublinear adaptive complexity for the problem and yields algorithms comparable to the state-of-the-art even for the special cases of cardinality constraints or monotone objectives.

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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