Fault-Tolerant Facility Location: a randomized dependent LP-rounding algorithm

Abstract We give a new randomized LP-rounding 1.725-approximation algorithm for the metric Fault- Tolerant Uncapacitated Facility Location problem. This improves on the previously best known 2.076-approximation algorithmof Swamy & Shmoys. To the best of our knowledge, our work provides the first application of a dependent-rounding technique in the domain of facility location. The analysis of our algorithm benefits from, and extends, methods developed for Uncapacitated Facility Location; it also helps uncover new properties of the dependent-rounding approach. An important concept that we develop is a novel, hierarchical clustering scheme. Typically, LP-rounding approximation algorithms for facility location problems are based on partitioning facilities into disjoint clusters and opening at least one facility in each cluster. We extend this approach and construct a laminar family of clusters, which then guides the rounding procedure. It allows to exploit properties of dependent rounding, and provides a quite tight analysis resulting in the improved approximation ratio.


Published in:
Proceeding of the 14th Conference on Integer Programming and Combinatorial Optimization
Presented at:
14th Conference on Integer Programming and Combinatorial Optimization, Lausanne, June 9-11, 2010
Year:
2010
Publisher:
Springer-Verlag New York, Ms Ingrid Cunningham, 175 Fifth Ave, New York, Ny 10010 Usa
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 Record created 2010-02-02, last modified 2018-09-13

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