题目大概意思是:7个节点,彼此之间存在物流量w和距离d,要从中选出3个作为枢纽,但作为枢纽便有建设费用f,单位距离单位物流的成本为c,每个普通节点有且仅连接1个枢纽,且普通节点到枢纽的运输享受折扣a1,枢纽之间享受折扣a。现在建立模型,并用lingo求解。模型我已建,lingo也编写了,但是遇到了问题,希望有网友能够帮我解决。(具体的值我都已经赋好了,参见程序中)
lingo编程如下: model: sets: spoke/s1,s2,s3,s4,s5,s6,s7/:y,F; link(spoke,spoke,spoke,spoke):w,d; data: d=0 18.8 17.7 97.8 68 36.847.9 18.8 0 36.2 98.7 5927.7 35.6 17.7 36.2 0 112.6 82.851.6 65.3 97.8 98.7 112.6 0 76.297.5 105.4 68 59 82.8 76.2 0 33.934.9 36.8 27.7 51.6 97.533.9 0 23.5 47.9 35.6 63.3 105.434.9 23.5 0;
w=0,36.14,37.11,32.96,41.05,35.82,28.32, 41.63,0,19.62,17.42,21.70,18.94,14.97, 42.60,19.55,0,17.83,22.21,19.38,15.32, 38.41,17.62,18.10,0,20.02,17.47,13.81, 46.48,21.33,21.90,19.45,0,21.14,16.71, 41.31,18.96,19.47,17.29,21.53,0,14.86, 33.57,15.40,15.82,14.05,17.50,15.27,0; F=50000,50000,50000,30000,30000,30000,30000; c=50; a=0.7; a1=0.9; N=7; enddata min=@sum(spoke(k):y(k)*F(k))+@sum(spoke(i):@sum(spoke(j):@sum(spoke(k):@sum(spoke(m):w(i,j)*a1*d(i,k)*c+w(i,j)*a1*d(m,j)*c)))) +@sum(spoke(k):@sum(spoke(m)|k#NE#m:c*a*w(i,j)*d(m,j))); @sum(spoke(k):y(k)=3); @for(spoke(i):@for(spoke(k):@for(spoke(m):@for(spoke(j):x(i,k,m,j)<=y(k))))); @for(spoke(i):@for(spoke(k):@for(spoke(m):@for(spoke(j):x(i,k,m,j)<=y(m))))); @for(spoke(i):@sum(spoke(k):x(i,k,m,j)=1)); @for(spoke(j):@sum(spoke(m):x(i,k,m,j)=1)); end 在lingo里运行总是有问题,可是以自己现在的能力,暂时也不知道是怎么回事了,希望能有吧友帮帮忙,帮我看看,在此感谢了。
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