ZIMPL：约束中无法识别二维变量声明

Question

我在 Zimpl 中声明 2D 变量时遇到了真正的挑战。（参数似乎工作正常。）

以下是我的MWE：

set I := {1 to 10};
set J := {1 to 5};

param A[I*J] := read InputFile as "n+";
var x[I] binary;
var s[J] binary; # this works but doesn't do what I need
var s2[I*J] binary; # this does what I need but doesn't work

minimize sum<i,j> in I*J with A[i,j] < 5: (s2[i,j] - x[i]) * A[i,j];

# this constraint compiles
subto constraint1:
   forall <j> in J do sum <i> in I with A[i,j] < 5: x[i] <= 1 + s[j];

# this constraint does not compile
subto constraint2:
   forall <j> in J do sum <i> in I with A[i,j] < 5: x[i] <= 1 + s2[i,j];

当尝试创建我的 lp 文件时，我得到

Error 133: Unknown symbol "i"

有没有人对我如何使第二个约束起作用有任何见解？据我所知，这与 Zimpl 用户手册中的容量设施问题（第 6.3 节）的实现相同。

提前致谢。

Answer 1

您在约束的左侧有 i 的总和，但在右侧也有引用 i。你期望 i 的值是多少？

可行的是

forall <j> in J do sum <i> in I with A[i,j] < 5: (x[i] - s2[i,j]) <= 1;

但我不确定这是否是您想要实现的目标。

添加 Leon 的评论以做出更完整的回答：

To add to what Gerald wrote, in ZIMPL sums always only consider the next variable, so you have to put parenthesis to make it work.

Answer 2

补充一下 Gerald 写的，在 ZIMPL 求和中总是只考虑下一个变量，所以你必须加上括号才能让它起作用。

Answer 3

在最小化时缺少名称。它应该最小化 obj: sum ...

ZIMPL：约束中无法识别二维变量声明

ZIMPL: 2D variable declaration not recognized in constraint

linear-programming

scip