吉林大学学报(理学版)

• 计算机科学 • 上一篇    下一篇

基于MAC的动态回溯算法优化

许苍竹1,2, 郝爽1,3, 李博宇1,2, 刘明慧1,2   

  1. 1. 吉林大学 符号计算与知识工程教育部重点实验室, 长春 130012;2. 吉林大学 计算机科学与技术学院, 长春 130012; 3. 吉林大学 软件学院, 长春 130012
  • 收稿日期:2014-05-12 出版日期:2015-03-26 发布日期:2015-03-24
  • 通讯作者: 许苍竹 E-mail:bamboo5431@163.com

Optimizing the Dynamic Backtracking Based on MAC

XU Cangzhu1,2, HAO Shuang1,3, LI Boyu1,2, LIU Minghui1,2   

  1. 1. Key Laboratory of Symbolic Computation and Knowledge Engineering for Ministry of Education, Jilin University,[JP]Changchun 130012, China; 2. College of Computer Science and Technology, Jilin University,Changchun 130012, China; 3. College of Software, Jilin University, Changchun 130012, China
  • Received:2014-05-12 Online:2015-03-26 Published:2015-03-24
  • Contact: XU Cangzhu E-mail:bamboo5431@163.com

摘要:

针对基于MAC的动态回溯算法在求解约束满足问题时, 不仅需要大量空间存储删除解释, 而且回溯机制过于复杂, 对经典的删除解释及动态回溯算法的回溯机制进行优化, 优化后的动态回溯算法减少了存储删除解释的空间, 并可仅使用一次回溯操作返回到可能导致冲突的关键变量. 在最差情况下, 存储删除解释的空间复杂度由O(n2d)改进为O(nd+n2). 通过结合restart技术使优化后的动态回溯算法成为完备算法. 实验结果表明, 优化后的完备动态回溯算法在大部分问题求解中, 整体效率明显优于标准回溯算法.

关键词: 人工智能, 约束满足问题, 动态回溯算法, 删除解释

Abstract:

On coping with constraint satisfaction problems by means of classical dynamic backtracking based on MAC, it costs much space to store eliminating explanation, and the backtracking mechanism is too complex. Thus we optimized the classic eliminating explanation and the backtracking mechanism of the dynamic backtracking algorithm. The optimized dynamic backtracking algorithm compresses the space of recording eliminating explanation, and returns to
 the key variable that may lead to confliction via only one backtrack operation. In the worst case, the space complexity of storing eliminating explanation declines from O(n2d) to O(nd+n2). The optimized dynamic backtracking algorithm combines with restart technology for further improvement to become a complete algorithm. Experimental results show that the efficiency of the complete optimized dynamic backtracking algorithm is prior to that of standard backtracking in solving most problems.

Key words: artificial intelligence, constraint satisfaction problems, dynamic backtracking, eliminating explanation

中图分类号: 

  • TP18