model: sets: row1/1..20/:CUST; row2/1..5/:CENTER; endsets data: CUSTOMER_X_COORD(CUST) := <2, 3, 8, 7, 6, 5, 1, 9, 6, 4, 5, 3, 1, 7, 2, 9, 8, 4, 6, 10>; CUSTOMER_Y_COORD(CUST) := <5, 1, 2, 3, 4, 7, 10, 2, 6, 9, 3, 1, 4, 5, 7, 10, 4, 5, 8, 9>; CENTER_X_COORD(CENTER) := <1, 3, 6, 8, 10>; CENTER_Y_COORD(CENTER) := <1, 3, 5, 7, 9>; EndData DataRef: CUSTOMER_X_COORD, CUSTOMER_Y_COORD, CENTER_X_COORD, CENTER_Y_COORD; EndDataRef Table COST_MATRIX(CUST, CENTER) = SQRT((CUSTOMER_X_COORD(CUST)-CENTER_X_COORD(CENTER))^2 + (CUSTOMER_Y_COORD(CUST)-CENTER_Y_COORD(CENTER))^2); Variables: X(CUST, CENTER), Binary; Y(CENTER), Binary; EndVariables Minimize Total_Cost : = sum((i, j, k | k ~= j), X(i,j,k) * COST_MATRIX(i,j)); Subject to Constraint1(i in CUST): sum(X(i,j,k) * CAPACITY(i) | j in CENTER, k in CENTER) <= sum(Y(j) * VEHICLE_NUMBER(j) | j in CENTER); Constraint2(j in CENTER): sum(Y(j)) = 1; Constraint3(i in CUST): sum(X(i,j,k) | j in CENTER, k in CENTER) = 1; Constraint4(i in CUST, j in CENTER): sum(X(i,j,k) | k in CENTER) <= Y(j); End更改一下这段Lingo代码

以下是对代码进行的一些修改：

1. 在Sets部分，将row1改为CUST，将row2改为CENTER，使得集合名称更直观。

2. 在Variables部分，将变量Y的类型改为Integer，使得变量Y只能取0或1两个值。

3. 在Minimize部分，将目标函数中的不等式符号“~=”改为“<>”，表示不等于。

4. 在Constraint1部分，添加了一个新的参数CAPACITY(i)，表示第i个客户所需的货物容量。

5. 在Constraint2部分，将约束条件改为大于等于1，保证每个中心至少分配给一个客户。

修改后的代码如下：

model:
    Sets:
        CUST /1..20/;
        CENTER /1..5/;
    Endsets

    Data:
        CUSTOMER_X_COORD(CUST) := <2, 3, 8, 7, 6, 5, 1, 9, 6, 4, 5, 3, 1, 7, 2, 9, 8, 4, 6, 10>;
        CUSTOMER_Y_COORD(CUST) := <5, 1, 2, 3, 4, 7, 10, 2, 6, 9, 3, 1, 4, 5, 7, 10, 4, 5, 8, 9>;
        CENTER_X_COORD(CENTER) := <1, 3, 6, 8, 10>;
        CENTER_Y_COORD(CENTER) := <1, 3, 5, 7, 9>;
        CAPACITY(CUST) := <20, 10, 30, 15, 5, 25, 20, 10, 15, 30, 10, 20, 25, 5, 15, 30, 20, 10, 25, 5>;
        VEHICLE_NUMBER(CENTER) := <2, 3, 1, 2, 1>;
    EndData

    DataRef:
        CUSTOMER_X_COORD, CUSTOMER_Y_COORD, CENTER_X_COORD, CENTER_Y_COORD, CAPACITY, VEHICLE_NUMBER;
    EndDataRef

    Table COST_MATRIX(CUST, CENTER) =
        SQRT((CUSTOMER_X_COORD(CUST)-CENTER_X_COORD(CENTER))^2
        + (CUSTOMER_Y_COORD(CUST)-CENTER_Y_COORD(CENTER))^2);

Variables:
    X(CUST, CENTER), Binary;
    Y(CENTER), Integer;
EndVariables

Minimize
    Total_Cost : = sum((i, j, k | k <> j), X(i,j,k) * COST_MATRIX(i,j));
Subject to
    Constraint1(i in CUST):
        sum(X(i,j,k) * CAPACITY(i) | j in CENTER, k in CENTER) <= sum(Y(j) * VEHICLE_NUMBER(j) | j in CENTER);

    Constraint2(j in CENTER):
        sum(Y(j)) >= 1;

    Constraint3(i in CUST):
        sum(X(i,j,k) | j in CENTER, k in CENTER) = 1;

    Constraint4(i in CUST, j in CENTER):
        sum(X(i,j,k) | k in CENTER) <= Y(j);
End