Space-efficient parallel algorithms for combinatorial search problems

作者：Pietracaprina A^*; Pucci G; Silvestri F; Vandin F

来源：Journal of Parallel and Distributed Computing, 2015, 76: 58-65.

DOI：10.1016/j.jpdc.2014.09.007

• Combinatorial search problems
• Distributed algorithms
• Backtrack search
• Branch-and-bound
• Space-efficient algorithms

We present space-efficient parallel strategies for two fundamental combinatorial search problems, namely, backtrack search and branch-and-bound, both involving the visit of an n-node tree of height h under the assumption that a node can be accessed only through its father or its children. For both problems we propose efficient algorithms that run on a p-processor distributed-memory machine. For backtrack search, we give a deterministic algorithm running in 0 (n/p + h logp) time, and a Las Vegas algorithm requiring optimal 0 (n/p + h) time, with high probability. Building on the backtrack search algorithm, we also derive a Las Vegas algorithm for branch-and-bound which runs in 0 ((n/p + h logp log n)h log(2) n) time, with high probability. A remarkable feature of our algorithms is the use of only constant space per processor, which constitutes a significant improvement upon previous algorithms whose space requirements per processor depend on the (possibly huge) tree to be explored.

• 出版日期2015-2