Nearly-Linear Work Parallel SDD Solvers, Low-Diameter Decomposition, and Low-Stretch Subgraphs

We present the design and analysis of a nearly-linear work parallel algorithm for solving symmetric diagonally dominant (SDD) linear systems. On input an SDD n -by- n matrix A with m nonzero entries and a vector b , our algorithm computes a vector such that in work and depth for any θ >0, where A...

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Bibliographic Details
Published in:Theory of computing systems Vol. 55; no. 3; pp. 521 - 554
Main Authors: Blelloch, Guy E., Gupta, Anupam, Koutis, Ioannis, Miller, Gary L., Peng, Richard, Tangwongsan, Kanat
Format: Journal Article
Language:English
Published: Boston Springer US 01.10.2014
Springer Nature B.V
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ISSN:1432-4350, 1433-0490
Online Access:Get full text
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Summary:We present the design and analysis of a nearly-linear work parallel algorithm for solving symmetric diagonally dominant (SDD) linear systems. On input an SDD n -by- n matrix A with m nonzero entries and a vector b , our algorithm computes a vector such that in work and depth for any θ >0, where A + denotes the Moore-Penrose pseudoinverse of  A . The algorithm relies on a parallel algorithm for generating low-stretch spanning trees or spanning subgraphs. To this end, we first develop a parallel decomposition algorithm that in O ( m log O (1) n ) work and polylogarithmic depth, partitions a graph with n nodes and m edges into components with polylogarithmic diameter such that only a small fraction of the original edges are between the components. This can be used to generate low-stretch spanning trees with average stretch O ( n α ) in O ( m log O (1) n ) work and O ( n α ) depth for any α >0. Alternatively, it can be used to generate spanning subgraphs with polylogarithmic average stretch in O ( m log O (1) n ) work and polylogarithmic depth. We apply this subgraph construction to derive a parallel linear solver. By using this solver in known applications, our results imply improved parallel randomized algorithms for several problems, including single-source shortest paths, maximum flow, minimum-cost flow, and approximate maximum flow.
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ISSN:1432-4350
1433-0490
DOI:10.1007/s00224-013-9444-5