Research Article

A PTAS for the average weighted completion time problem on unrelated machines

  1. Foto Afrati1,
  2. Evripidis Bampis2,*,
  3. Claire Kenyon3,
  4. Ioannis Milis4

Article first published online: 27 OCT 2000

DOI: 10.1002/1099-1425(200011/12)3:6<323::AID-JOS52>3.0.CO;2-E

Issue

Journal of Scheduling

Journal of Scheduling

Special Issue: Approximation Algorithms: Part 2

Volume 3, Issue 6, pages 323–332, November/December 2000

Additional Information

How to Cite

Afrati, F., Bampis, E., Kenyon, C. and Milis, I. (2000), A PTAS for the average weighted completion time problem on unrelated machines. Journal of Scheduling, 3: 323–332. doi: 10.1002/1099-1425(200011/12)3:6<323::AID-JOS52>3.0.CO;2-E

Author Information

  1. 1

    NTUA, Division of Computer Science, Heroon Polytechniou 9, 15773, Athens, Greece

  2. 2

    LaMI, Université d'Evry, Boulevard François Mitterrand, 91025 Evry Cedex, France

  3. 3

    LRI, Bât. 490, Université Paris-Sud, 91405 Orsay Cedex, France

  4. 4

    Athens University of Economics, Department of Informatics, Patission 76, 10434 Athens, Greece

*LaMI, Université d'Evry, Boulevard François Mitterrand, 91025 Evry Cedex, France

Publication History

  1. Issue published online: 27 OCT 2000
  2. Article first published online: 27 OCT 2000

Funded by

  • PLATON
  • French Ministry of National Education, Research and Technology

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Keywords:

  • unrelated machines;
  • PTAS;
  • approximation

Abstract

We study the problem of scheduling n independent weighted jobs on a constant number of unrelated parallel machines so as to minimize the weighted sum of job completion times Rm∣∣∑wjCj. We present an O(n log n) time approximation scheme for the non-preemptive case of this problem. Notice that when the number of machines is not a constant (i.e. R∣∣∑wjCj) then no PTAS is possible, unless ��=����. Copyright © 2000 John Wiley & Sons, Ltd.

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