Precedence constrained scheduling: A case in P

Politopoulos, K; Georgakopoulos, GF; Tsanakas, P

dc.contributor.author	Politopoulos, K	en
dc.contributor.author	Georgakopoulos, GF	en
dc.contributor.author	Tsanakas, P	en
dc.date.accessioned	2014-03-01T01:16:58Z
dc.date.available	2014-03-01T01:16:58Z
dc.date.issued	2001	en
dc.identifier.issn	0010-4620	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/14290
dc.subject.classification	Computer Science, Hardware & Architecture	en
dc.subject.classification	Computer Science, Information Systems	en
dc.subject.classification	Computer Science, Software Engineering	en
dc.subject.other	Algorithms	en
dc.subject.other	Computational complexity	en
dc.subject.other	Constraint theory	en
dc.subject.other	Graph theory	en
dc.subject.other	Online systems	en
dc.subject.other	Polynomials	en
dc.subject.other	Response time (computer systems)	en
dc.subject.other	Scheduling	en
dc.subject.other	Theorem proving	en
dc.subject.other	Limited lookahead technique	en
dc.subject.other	Precedence constrained scheduling	en
dc.subject.other	Task graphs	en
dc.subject.other	Unit execution time	en
dc.subject.other	Parallel processing systems	en
dc.title	Precedence constrained scheduling: A case in P	en
heal.type	journalArticle	en
heal.identifier.primary	10.1093/comjnl/44.3.163	en
heal.identifier.secondary	http://dx.doi.org/10.1093/comjnl/44.3.163	en
heal.language	English	en
heal.publicationDate	2001	en
heal.abstract	'Unit execution time' precedence constrained scheduling (UET) is an NP-complete problem with very few special cases known to be solvable in P-time. In this article we present a practically useful case of UET solvable in P-time: We show that if the task graph is given in levels that are 'locally' of in-degree two and of 'width' more than 1.55 times the number of processors (plus 1), then an optimal schedule can be found in P-time. Task graphs which represent algebraic computations fall ordinarily in this category. Our algorithm is based on a limited look-ahead technique which allows us to use it in an on-line fashion. In the appendix we give two short NP-completeness proofs which suggest that both 'width' and 'degree' restrictions are needed to get a polynomially solvable subcase.	en
heal.publisher	OXFORD UNIV PRESS	en
heal.journalName	Computer Journal	en
dc.identifier.doi	10.1093/comjnl/44.3.163	en
dc.identifier.isi	ISI:000169766600003	en
dc.identifier.volume	44	en
dc.identifier.issue	3	en
dc.identifier.spage	163	en
dc.identifier.epage	173	en