floyd算法计算最短距离时，赋权邻接矩阵怎么算

Model:
!2个工厂，3个中转站及4个客户的运输问题;
sets:
plant/A,B/:produce;
warhouse/x,y,z/;
costomer/1..4/:require;
link(plant, warhouse,costomer):poss,cost,x;