从 OPL/CPLEX 中现有集合的组件创建新集合

Question

我有一个已读入我的 OPL 项目的集合，如下所示：

S = {<"A","">, <"B","">, <"AB","A">, <"AB","B">, <"C","">, <"ABC","A">,<"ABC","B">, <"ABC","C">, <"ABC","AB">},

其中每个元素 <,> 是一个包含两个字符串元素的元组。该集合表示感兴趣的项目之间的父子关系。

我需要从这个集合创建一个新集合：

S' = {<"A",{""}>, <"B",{""}>, <"C",{""}>, <"AB",{"A","B"}>, <"ABC",{"A","B","C","AB"}>},

其中每个元素 <,> 是一个元组，每个元组的第一个元素是一个字符串，每个元组的第二个元素是一组字符串。我创建此集合的尝试是：

tuple child{
    string Item;
    string Child; 
 }

 {child} Children = ...; //Reads in the set S

 tuple dependents{
    string Item;
    {string} ItemChildren; 
 } 

 {dependents} dependentsSet = {<x.Item, y.Child> | x in Children, (y in Children : <x,y> in Children)};

使用上面代码中的变量名，创建S'的目的是因为稍后在我的程序中我需要创建一组约束，每个Item一个，在每个约束中，我需要对 ItemChildren 进行索引。我是 OPL 的相对新手，所以我知道我在 dependentsSet 变量的初始化中错误地使用了语法，但我不知道如何正确编写此语句以创建我正在寻找的集合。

任何人都可以帮助我理解创建我想要的集合所需的语句吗？

Answer 1

tuple child{
    string Item;
    string Child; 
 }

 {child} Children 
  = {<"A","">, <"B","">, <"AB","A">, <"AB","B">, <"C","">, <"ABC","A">,
  <"ABC","B">, <"ABC","C">, <"ABC","AB">};

{string} setOfParents={i.Item | i in Children};
{string} setOfChildren={i.Child | i in Children};

 tuple dependents{
    string Item;
    {string} ItemChildren; 
 } 

 {string} kids[p in setOfParents]={k | k in setOfChildren : <p,k> in Children};

 {dependents} dependentsSet = {<x, kids[x]> | x in setOfParents};
 execute
 {

 writeln(dependentsSet);
}

给予

 {<"A" {""}> <"B" {""}> <"AB" {"A" "B"}> <"C" {""}>
 <"ABC" {"A" "B" "C" "AB"}>}

从 OPL/CPLEX 中现有集合的组件创建新集合

Creating a new set from components of an existing set in OPL/CPLEX

optimization

mathematical-optimization

linear-programming

cplex

opl