Scheduling with Concurrency-Based Constraints
This paper considers scheduling problems with timing constraints of the forms < (precedence), ≤ (no later than), and ≐ (concurrence). Scheduling unit-time jobs subject to < and ≐ constraints, and scheduling unit-time jobs subject to ≤ constraints, are proved NP-complete for fixed k ≥ 3 process...
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| Published in: | Journal of algorithms Vol. 18; no. 1; pp. 98 - 123 |
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| Main Authors: | , |
| Format: | Journal Article |
| Language: | English |
| Published: |
San Diego, CA
Elsevier Inc
1995
Elsevier |
| Subjects: | |
| ISSN: | 0196-6774, 1090-2678 |
| Online Access: | Get full text |
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| Summary: | This paper considers scheduling problems with timing constraints of the forms < (precedence), ≤ (no later than), and ≐ (concurrence). Scheduling unit-time jobs subject to < and ≐ constraints, and scheduling unit-time jobs subject to ≤ constraints, are proved NP-complete for fixed
k ≥ 3 processors. (This contrasts with the case of just < constraints, which is a famous open problem.) We then show that a modified version of Gabow′s linear time 2-processor scheduling algorithm can optimally handle all three types of constraints. Linear time and NC algorithms for optimally scheduling with any subset of {<, ≤, ≐ } constraints are thus obtained for
k = 2 processors. Approximation results for
k ≥ 3 processors are also obtained. Finally, we consider a problem that arises in practice on the Tera architecture, proving an NP-completeness result and providing an approximation algorithm. |
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| ISSN: | 0196-6774 1090-2678 |
| DOI: | 10.1006/jagm.1995.1003 |