c# - 方法作为 Microsoft Solver Foundation 中的目标函数？

Question

这是一个典型的 MSF 优化公式:

using Microsoft.SolverFoundation.Services;

SolverContext context = SolverContext.GetContext();
Model model = context.CreateModel();

//decisions
Decision xs = new Decision(Domain.Real, "Number_of_small_chess_boards");
Decision xl = new Decision(Domain.Real, "Number_of_large_chess_boards");

model.AddDecisions(xs, xl);

//constraints
model.AddConstraints("limits", 0 <= xs, 0 <= xl);
model.AddConstraint("BoxWood", 1 * xs + 3 * xl <= 200);
model.AddConstraint("Lathe", 3 * xs + 2 * xl <= 160);

//Goals
model.AddGoal("Profit", GoalKind.Maximize, 5 * xs + 20 * xl);

// This doesn't work!
// model.AddGoal("Profit", GoalKind.Maximize, objfunc(xs, xl));


Solution sol = context.Solve(new SimplexDirective());
Report report = sol.GetReport();
Console.WriteLine(report);

是否可以使用单独的方法而不是像“5 * xs + 20 * xl”这样的语句作为目标函数？例如，像下面这样的方法？怎么办？

// this method doesn't work!
static double objfunc(Decision x, Decision y)
{
    return 5 * x.ToDouble() + 20 * y.ToDouble();
}

Answer 1

就这么简单:

 static Term objfunc(Decision x, Decision y)
        {
            return 5 * x + 20 * y;
        }

函数必须返回一个 Term，而不是返回一个 double。