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Author Ajwani, Deepak ♦ Cosgaya-Lozano, Adan ♦ Zeh, Norbert
Source ACM Digital Library
Content type Text
Publisher Association for Computing Machinery (ACM)
File Format PDF
Copyright Year ©2012
Language English
Subject Domain (in DDC) Computer science, information & general works ♦ Computer programming, programs & data
Subject Keyword External-memory algorithms ♦ Graph algorithms
Abstract We present an I/O-efficient algorithm for topologically sorting directed acyclic graphs, called IterTS. In the worst case, our algorithm is extremely inefficient and performs $O(\textit{n}$ ċ $sort(\textit{m}))$ I/Os. However, our experiments show that IterTS achieves good performance in practice. To evaluate IterTS, we compared its running time to those of three competitors: PeelTS, an I/O-efficient implementation of the standard strategy of iteratively removing sources and sinks; ReachTS, an I/O-efficient implementation of a recent parallel divide-and-conquer algorithm based on reachability queries; and SeTS, a standard DFS-based topological sorting built on top of a semiexternal DFS algorithm. In our evaluation on various types of input graphs, IterTS consistently outperformed PeelTS and ReachTS by at least an order of magnitude in most cases. SeTS outperformed IterTS on most graphs whose vertex sets fit in memory. However, IterTS often came close to the running time of SeTS on these inputs and, more importantly, SeTS was not able to process graphs whose vertex sets were beyond the size of main memory, while IterTS was able to process such inputs efficiently.
ISSN 10846654
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2012-09-01
Publisher Place New York
e-ISSN 10846654
Journal Journal of Experimental Algorithmics (JEA)
Volume Number 17
Page Count 21
Starting Page 3.1
Ending Page 3.21


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Source: ACM Digital Library