数学建模 TSP(旅行商问题) Lingo求解

model:

sets:

cities/../:level;

link(cities, cities): distance, x;   !距离矩阵;

endsets

data:

distance =

                                            ;

enddata

n = @size(cities);

!目标函数;

min=@sum(link:distance * x);

@For(cities(k):

     !进入城市k;

     @sum(cities(i) | i #ne# k: x(i,k)) = ;

     !离开城市k;

     @sum(cities(j) | j #ne# k: x(k,j)) = ;

    );

    !保证不出现子圈;

    @for(cities(i) | i #gt# :

    @for(cities(j) | j #gt#  #and# i#ne#j:

        level(i)-level(j) + n*x(i,j) <= n-);

     );

    !限制u的范围以加速模型的求解，保证所加限制并不排除掉TSP问题的最优解;

    @for(cities(i) | i #gt# : level(i) <= n-);

    !定义x为 \1变量;

    @for(link:@bin(x));

end