如何使用Choco solver framework for Java对特殊集合约束建模

Question

我在建模一个问题并用Java中的Choco solver解决它时遇到了问题，我一开始对约束编程不太熟悉，但我的任务是为会议制作一个座位应用程序，其中：

• 每张桌子必须至少有6个人，而且总是有足够的桌子
• 人们应该与邻居坐在一起，以最大限度地实现共同利益
• 在之前的几天里，我们希望尽量减少人们和他们之前坐过的人一起坐在桌子上
• 人们要么属于A类，要么属于B类，我们希望在每张桌子上尽量减少A类的出现

到目前为止，我们有一个SetVar guest_列表，其中包括1至1名客人。然后将guest_列表划分到SetVar[]表中。

但是我如何约束每个table.size

如何在两个集合之间设置约束，以最小化成员/交点？

我不知道如何在一个集合内为邻居建模，以最大限度地实现共同利益。

import org.chocosolver.solver.Model;
import org.chocosolver.solver.Solution;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.solver.variables.SetVar;

// constant value declarations
int number_of_guests = 100;
int table_size = 8;
int tables_needed = number_of_guests / table_size + 1;

// this will later be passed as argument, generated for testing
int[] guest_ids = new int[number_of_guests];
for (int i = 0; i < number_of_guests; i++) {
    guest_ids[i] = i;
}

// Model and variables
Model model = new Model("Seating solver");

IntVar min_guests_at_tables = model.intVar(6);
// a list containing all guests in its LB
SetVar guest_list  = model.setVar("guests", guest_ids);
// making empty sets for each table needed, UB is all guests
SetVar[] tables = model.setVarArray(tables_needed, new int[]{}, guest_ids);
// log over table seatings from earlier days, starts empty for day 1.
// want to minimize how many members from tables[x] share with any ser of logged_tables
SetVar[] logged_tables = model.setVarArray(0, new int[]{}, new int[]{});
// a setvar of all interests for each guest, will be imported later.
SetVar[] guest_interests = model.setVarArray(number_of_guests, new int[]{}, new int[]{});
// set of all those members of group A
// random test values inserted
SetVar group_A_members = model.setVar(1,23,54,2);

// Constraints unsure about all of these

// each set must be unique
model.allDifferent(tables);
for (SetVar table : tables) {
    // TODO trying to constrain sizes of each table set to 6 or greater
    model.arithm(model.intVar(table.getLB().size()), ">=", min_guests_at_tables);
// TODO trying to minimize number of shared members in tables, with whats in logged_tables
for (SetVar old_table : logged_tables) {
    // no idea
}
// TODO trying to maximize the amount of interest neigbors in a set share
// no idea

// TODO minimize shared members from table with group_A_members
// no idea how to minimize or maximize
}

// Solving

Solution s = model.getSolver().findSolution();
if (s != null) System.out.println(s.toString());

Answer 1

可以从实现IConstraintFactory的model访问可用约束集。看看ISetConstraintFactory。源代码中的java。存在与设置大小、联合、分区相关的约束。。。