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Parallelization of probabilistic sequential search algorithms

Thesis/Dissertation ·
OSTI ID:5827878

The author compares some strategies for the parallelization of probabilistic sequential search algorithms. He is concerned with those probabilistic sequential search algorithms which generate a sequence of candidate solutions where each solution is generated from the previous one by the application of a probabilistic local improvement operator. Two good examples of such algorithms are Lin's 2-opt strategy for the Traveling Salesman Problem and Simulated Annealing. He explores the concept of searching by a pool of candidate solutions. In this work he compares some strategies of parallelization of Lin and Kernighan's 2-opt operator for the Traveling Salesman Problem. In particular, he studies the tradeoffs between processors working independently and processors communicating at regular intervals. Communication in this case involves exchanging information about good tours. He shows that a good strategy of parallelization is one that involves communication at fairly regular intervals. He explores some strategies for information exchange like redistributing the current best tour at regular intervals, redistributing k best tours at regular intervals and so on. He also explores the selection strategy, of Holland's Genetic Algorithms as a strategy for information exchange. He also explores the quick approximate evaluation of tour lengths to determine the fitness of each tour for information exchange. This is a study of searching by a pool of candidate solutions on a parallel machine. This is an interesting technique in that good strategies are very robust and it is possible to introduce other operators like the structural exchange operator which is well suited for a parallel machine and can improve the performance.

Research Organization:
Indiana Univ., Bloomington, IN (USA)
OSTI ID:
5827878
Country of Publication:
United States
Language:
English

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