A Branch and Bound Algorithm for a Class of Asymmetrical Vehicle Routeing Problems
针对一类非对称车辆路径问题（车辆从中心仓库出发，访问分组节点，有最少访问次数、容量和距离限制），提出分支定界算法，利用子问题的幺模矩阵结构求解，并报告计算结果。
This paper describes a branch and bound algorithm for a general class of asymmetrical vehicle routeing problems. Vehicle routes start and end at a central depot. Visits are made to nodes grouped into clusters: every cluster must receive a minimum number of visits. But not all nodes must be visited: there are specified nodes and non-specified nodes. Vehicle routes are also constrained by capacity and distance restrictions. The problem is formulated as an integer linear program. It is then solved by a branch and bound algorithm which exploits the unimodular structure of the subproblems. Computational results are reported.