On designing optimal parallel triangular solvers

This paper explores the problem of solving triangular linear systems on parallel distributed-memory machines. Working within the LogP model, tight asymptotic bounds for solving these systems using forward/backward substitution are presented. Specifically, lower bounds on execution time independent o...

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Bibliographic Details
Published in:Information and computation Vol. 161; no. 2; pp. 172 - 210
Main Author: Santos, Eunice E.
Format: Journal Article
Language:English
Published: San Diego, CA Elsevier Inc 2000
Elsevier
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ISSN:0890-5401, 1090-2651
Online Access:Get full text
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Summary:This paper explores the problem of solving triangular linear systems on parallel distributed-memory machines. Working within the LogP model, tight asymptotic bounds for solving these systems using forward/backward substitution are presented. Specifically, lower bounds on execution time independent of the data layout, lower bounds for data layouts in which the number of data items per processor is bounded, and lower bounds for specific data layouts commonly used in designing parallel algorithms for this problem are presented in this paper. Furthermore, algorithms are provided which have running times within a constant factor of the lower bounds described. One interesting result is that the popular two-dimensional block matrix layout necessarily results in significantly longer running times than simpler one-dimensional schemes. Finally, a generalization of the lower bounds to banded triangular linear systems is presented.
ISSN:0890-5401
1090-2651
DOI:10.1006/inco.2000.2866