C# Google或tools库中约束的布尔运算
我是约束编程的初学者,正在c#程序中使用 我想向我的解算器添加以下约束:C# Google或tools库中约束的布尔运算,c#,constraint-programming,boolean-operations,or-tools,C#,Constraint Programming,Boolean Operations,Or Tools,我是约束编程的初学者,正在c#程序中使用 我想向我的解算器添加以下约束: ((t1>=12&&t1=16&&t2首先,必须为域定义变量(例如正整数)。 然后,在要求解算器求解之前,定义约束和目标函数 您可以轻松地将以下C 代码示例转换为您的问题: string solverType = "GLPK_MIXED_INTEGER_PROGRAMMING"; Solver solver = Solver.CreateSolver("IntegerProgramming", solver
((t1>=12&&t1=16&&t2首先,必须为域定义变量(例如正整数)。 然后,在要求
解算器
求解之前,定义约束和目标函数
您可以轻松地将以下C
代码示例转换为您的问题:
string solverType = "GLPK_MIXED_INTEGER_PROGRAMMING";
Solver solver = Solver.CreateSolver("IntegerProgramming", solverType);
if (solver == null)
{
Console.WriteLine("Could not create solver " + solverType);
return;
}
// x1 and x2 are integer non-negative variables.
Variable x1 = solver.MakeIntVar(0.0, double.PositiveInfinity, "x1");
Variable x2 = solver.MakeIntVar(0.0, double.PositiveInfinity, "x2");
// Minimize x1 + 2 * x2.
Objective objective = solver.Objective();
objective.SetMinimization();
objective.SetCoefficient(x1, 1);
objective.SetCoefficient(x2, 2);
// 2 * x2 + 3 * x1 >= 17.
Constraint ct = solver.MakeConstraint(17, double.PositiveInfinity);
ct.SetCoefficient(x1, 3);
ct.SetCoefficient(x2, 2);
int resultStatus = solver.Solve();
// Check that the problem has an optimal solution.
if (resultStatus != Solver.OPTIMAL)
{
Console.WriteLine("The problem does not have an optimal solution!");
return;
}
Console.WriteLine("Problem solved in " + solver.WallTime() +
" milliseconds");
// The objective value of the solution.
Console.WriteLine("Optimal objective value = " + objective.Value());
// The value of each variable in the solution.
Console.WriteLine("x1 = " + x1.SolutionValue());
Console.WriteLine("x2 = " + x2.SolutionValue());
Console.WriteLine("Advanced usage:");
Console.WriteLine("Problem solved in " + solver.Nodes() +
" branch-and-bound nodes");
抄袭自
另一个简单方法是:
不幸的是,Google或tools库没有提供丰富的逻辑约束。如果您可以用Java开发实现,我建议您使用它,其中包括一个具有大量SAT约束的SAT解算器 在Google或tools中,当前制定逻辑约束的方法是将其转换为线性约束。最好先检查以了解转换的概念,然后查看HakanK的示例。此实现的一部分与逻辑约束相关:
// if (i != j) =>
// ((richer[i,j] = 1) <=> (richer[j,i] = 0))
for(int i = 0; i < n; i++) {
for(int j = 0; j < n; j++) {
if (i != j) {
solver.Add((richer[i, j]==1) - (richer[j, i]==0) == 0);
}
}
}
//如果(i!=j)=>
//((富[i,j]=1)(富[j,i]=0))
对于(int i=0;i
您还可以检查。您可以使用
MakeMin
和MakeMax
分别对连接和分离进行编码。对每个片段进行编码后,您将得到如下结果:
var solver=new solver(“MY_CP_solver”);
var t1=solver.MakeIntVar(12,20,“t1”);
var t1ge=solver.makegreaterrequal(t1,12);
var t1le=solver.MakeLessOrEqual(t1,15);
var t1eath=solver.MakeMin(t1ge,t1le);
var t2=solver.MakeIntVar(12,20,“t2”);
var t2ge=solver.makegreaterrequal(t2,16);
var t2le=solver.MakeLessOrEqual(t2,18);
var t2both=solver.MakeMin(t2ge,t2le);
var或=solver.MakeMax(t1both,t2both);
求解器。添加(或==1);
求解器添加(t1+t2<30);
var db=solver.MakePhase(新[]{t1,t2},solver.CHOOSE_FIRST_UNBOUND,solver.ASSIGN_MIN_VALUE);
求解器。求解(db);
while(solver.NextSolution())
WriteLine($“t1:{t1.Value()},t2:{t2.Value()}”);
输出:
t1: 12, t2: 12
t1: 12, t2: 13
t1: 12, t2: 14
t1: 12, t2: 15
t1: 12, t2: 16
t1: 12, t2: 17
t1: 13, t2: 12
t1: 13, t2: 13
t1: 13, t2: 14
t1: 13, t2: 15
t1: 13, t2: 16
t1: 14, t2: 12
t1: 14, t2: 13
t1: 14, t2: 14
t1: 14, t2: 15
t1: 15, t2: 12
t1: 15, t2: 13
t1: 15, t2: 14
特别是,析取中的第一个约束始终处于活动状态
使用较新的Google.OrTools.Sat.CpSolver
,您可以执行如下操作,其中我们引入了一个辅助布尔值b
,它的属性是确保至少满足析取中的一个子句:
var模型=新的CpModel();
var t1=model.NewIntVar(12,20,“t1”);
var t2=model.NewIntVar(12,20,“t2”);
var b=model.NewBoolVar(“第一个约束激活”);
model.Add(t1>=12)。仅限forceif(b);
model.Add(t1=16).OnlyEnforceIf(b.Not());
模型。添加(t2)这个。v=v;
public override void OnSolutionCallback()=>Console.WriteLine($“t1:{Value(v[0])},t2:{Value(v[1])}”);
私有只读IntVar[]v;
}
请注意,这将多次找到相同的
(t1,t2)
-对(但具有不同的b
)我的语言是python,我认为应该很容易将跟随python代码转换为C
model=cp\u model.CpModel()
t1=model.NewIntVar(12,20,“t1”)
t1_bool_ge=model.NewBoolVar(“t1_bool_ge”)
t1_bool_le=model.NewBoolVar(“t1_bool_le”)
t1_bool_and=model.NewBoolVar(“t1_bool_and”)
tmp_t1=[]
tmp_t1.append(t1_bool_ge)
tmp_t1.append(t1_bool_le)
model.Add(t1>=12)。仅限强制(t1\u bool\u ge)#t1>=12
模型。添加(t1=16
Add(t2)谢谢,但我正在寻找约束上的布尔运算。
Context ctx = new Context();
IntExpr t1 = ctx.MkIntConst("t1");
IntExpr t2 = ctx.MkIntConst("t2");
IntNum c12 = ctx.MkInt(12);
IntNum c15 = ctx.MkInt(15);
IntNum c16 = ctx.MkInt(16);
IntNum c18 = ctx.MkInt(18);
IntNum c30 = ctx.MkInt(30);
Solver solver = ctx.MkSolver();
BoolExpr constraintInterval12_15 =
ctx.MkAnd(ctx.MkLe(c12, t1), ctx.MkLe(t1, c15));
BoolExpr constraintInterval16_18 =
ctx.MkAnd(ctx.MkLe(c16, t2), ctx.MkLe(t2, c18));
BoolExpr constraintLe20 =
ctx.MkLt(ctx.MkAdd(t1, t2), c30);
solver.Assert(constraintLe20);
solver.Assert(ctx.MkOr(constraintInterval12_15, constraintInterval16_18));
if (solver.Check() == Status.SATISFIABLE)
{
Model m = solver.Model;
Console.WriteLine("t1 = " + m.Evaluate(t1));
Console.WriteLine("t2 = " + m.Evaluate(t2));
}
// if (i != j) =>
// ((richer[i,j] = 1) <=> (richer[j,i] = 0))
for(int i = 0; i < n; i++) {
for(int j = 0; j < n; j++) {
if (i != j) {
solver.Add((richer[i, j]==1) - (richer[j, i]==0) == 0);
}
}
}
t1: 12, t2: 12
t1: 12, t2: 13
t1: 12, t2: 14
t1: 12, t2: 15
t1: 12, t2: 16
t1: 12, t2: 17
t1: 13, t2: 12
t1: 13, t2: 13
t1: 13, t2: 14
t1: 13, t2: 15
t1: 13, t2: 16
t1: 14, t2: 12
t1: 14, t2: 13
t1: 14, t2: 14
t1: 14, t2: 15
t1: 15, t2: 12
t1: 15, t2: 13
t1: 15, t2: 14
model = cp_model.CpModel()
t1 = model.NewIntVar(12, 20, "t1")
t1_bool_ge = model.NewBoolVar("t1_bool_ge")
t1_bool_le = model.NewBoolVar("t1_bool_le")
t1_bool_and = model.NewBoolVar("t1_bool_and")
tmp_t1 = []
tmp_t1.append(t1_bool_ge)
tmp_t1.append(t1_bool_le)
model.Add(t1 >= 12).OnlyEnforceIf(t1_bool_ge) # t1 >=12
model.Add(t1 <= 15).OnlyEnforceIf(t1_bool_le) # t1 <= 15
model.Add(t1_bool_and==1).OnlyEnforceIf(tmp_t1) # (t1 >=12)&&(t1 <= 15)
t2 = model.NewIntVar(12, 20, "t2")
t2_bool_ge = model.NewBoolVar("t2_bool_ge")
t2_bool_le = model.NewBoolVar("t2_bool_le")
t2_bool_and = model.NewBoolVar("t2_bool_and")
tmp_t2 = []
tmp_t2.append(t2_bool_ge)
tmp_t2.append(t2_bool_le)
model.Add(t2 >= 16).OnlyEnforceIf(t2_bool_ge) # t2 >=16
model.Add(t2 <= 18).OnlyEnforceIf(t2_bool_le) # t2 <= 18
model.Add(t2_bool_and==1).OnlyEnforceIf(tmp_t2) #(t2 >=16) && (t2 <=18)
tmp_t1_t2 = []
tmp_t1_t2.append(t2_bool_and)
tmp_t1_t2.append(t1_bool_and)
model.Add(sum(tmp_t1_t2)==1) #((t1 >=12)&&(t1 <= 15))||((t2 >=16) && (t2 <=18))
model.Add(t1 + t2 < 30) # ( t1 + t2 ) < 30