Microsoft Solver Foundation Services声明性语法

Question

I have the following simple problem that I'd like to use to experiment with [MS Solver Foundation][1]:

I have 10 slots that I need to fill with integers in the range 1 to 5. I want to enforce only two constraints:

• slot[n] != slot[n + 1]
• the sum of all slots should be more than 20

I could simply create the following decisions:

Decision s1 = new Decision(Domain.IntegerRange(1, 5), "slot1");
Decision s2 = new Decision(Domain.IntegerRange(1, 5), "slot2");
Decision s3 = new Decision(Domain.IntegerRange(1, 5), "slot3");
Decision s4 = new Decision(Domain.IntegerRange(1, 5), "slot4");
Decision s5 = new Decision(Domain.IntegerRange(1, 5), "slot5");
Decision s6 = new Decision(Domain.IntegerRange(1, 5), "slot6");
Decision s7 = new Decision(Domain.IntegerRange(1, 5), "slot7");
Decision s8 = new Decision(Domain.IntegerRange(1, 5), "slot8");
Decision s9 = new Decision(Domain.IntegerRange(1, 5), "slot9");
Decision s10 = new Decision(Domain.IntegerRange(1, 5), "slot10");

And then setup constraints manually as in

model.AddConstraints("neighbors not equal",
               s1 != s2, s2 != s3, s3 != s4, s4 != s5,
               s5 != s6, s6 != s7, s7!= s8, s8 != s9, s9 != s10
               );

model.AddConstraint("sum",
              s1 + s2 + s3 + s4 + s5 + s6 + s7 + s8 + s9 + s10 > 20 );

However, I have to imagine that there's a better way to do this--hopefully in something more akin to declarative syntax.

Answer 1

The code.

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

Decision[] slot = new Decision[10];

for (int i = 0; i < slot.Length; i++)
{
    slot[i]  = new Decision(Domain.IntegerRange(1, 5), "slot" + i.ToString());
    model.AddDecision(slot[i]);
    if (i > 0) model.AddConstraint("neighbors not equal", slot[i-1] != slot[i]);
}

model.AddConstraint("sum", Model.Sum(slot) > 20);

Solution solution = context.Solve();

Answer 2

Discussions are moved to our official forum already:

http://code.msdn.microsoft.com/solverfoundation/Thread/View.aspx?ThreadId=2256

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