According to the running rules and steps, Petri net simulator can convert the nondirectional transportation net into EPN model and then work out its shortest path automatically.

• 定义 Petri网图仿真器的运行规则和步骤 ,用 Petri网图仿真器自动将无向运输网络转换成 EPN模型 ,然后自动求出相应的最短有向路径和路长。