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We present KADABRA, a new algorithm to approximate betweenness centrality in directed and undirected graphs, which significantly outperforms all previous approaches on real-world complex networks.
The efficiency of the new algorithm relies on two new theoretical contributions, of independent interest.
The first contribution focuses on sampling shortest paths, a subroutine used by most algorithms that approximate betweenness centrality. We show that, on realistic random graph models, we can perform this task in time |E|^{1/2+o(1)} with high probability, obtaining a significant speedup with respect to the Theta(|E|) worst-case performance. We experimentally show that this new technique achieves similar speedups on real-world complex networks, as well.
The second contribution is a new rigorous application of the adaptive sampling technique. This approach decreases the total number of shortest paths that need to be sampled to compute all betweenness centralities with a given absolute error, and it also handles more general problems, such as computing the k most central nodes. Furthermore, our analysis is general, and it might be extended to other settings, as well.
@InProceedings{borassi_et_al:LIPIcs.ESA.2016.20,
author = {Borassi, Michele and Natale, Emanuele},
title = {{KADABRA is an ADaptive Algorithm for Betweenness via Random Approximation}},
booktitle = {24th Annual European Symposium on Algorithms (ESA 2016)},
pages = {20:1--20:18},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-015-6},
ISSN = {1868-8969},
year = {2016},
volume = {57},
editor = {Sankowski, Piotr and Zaroliagis, Christos},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ESA.2016.20},
URN = {urn:nbn:de:0030-drops-63712},
doi = {10.4230/LIPIcs.ESA.2016.20},
annote = {Keywords: Betweenness centrality, shortest path algorithm, graph mining, sampling, network analysis}
}