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Criticality and parallelism in combinatorial optimization
Publisher:
  • Massachusetts Institute of Technology
  • 201 Vassar Street, W59-200 Cambridge, MA
  • United States
Order Number:AAI0597437
Pages:
1
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Abstract

Local search methods constitute one of the most successful approaches to solving large-scale combinatorial optimization problems. The objective of this thesis is to investigate the effects of parallelizing such methods. It will be demonstrated that as parallelism is increased, optimization performance initially improves, but then abruptly degrades to no better than random search beyond a certain point. This transition is surprisingly sharp and will be shown to share many of the characteristics of thermodynamic phase transitions. Its existence will be demonstrated for a family of generalized spin-glass models and the traveling salesman problem. Techniques from statistical mechanics are used to make the correspondence between the physics of phase transitions and the performance of parallelized optimizing systems more precise, demonstrating strong connections between these seemingly unrelated fields. Finite-size scaling is used to characterize size-dependent effects near the transition, and analytical insight is obtained through a mean-field approximation. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

Contributors
  • Massachusetts Institute of Technology
  • Massachusetts Institute of Technology

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