protected int[,] ComputeCosts(AssignmentDescription assignment)
{
int[,] costs = new int[assignment.Nodes.Count, assignment.Tasks.Count];
for (int j = 0; j < assignment.Tasks.Count; j++)
{
costs[0, j] = 500; // UNASSIGNED cost
if (assignment.Assignments[0].Contains(j)) // Not assigned yet.
{
for (int i = 1; i < assignment.Nodes.Count; i++)
{
costs[i, j] = 0; // No fee for assignment.
}
}
else
{
for (int i = 1; i < assignment.Nodes.Count; i++)
{
if (assignment.Assignments[i].Contains(j))
{
costs[i, j] = 0; // Don't move.
}
else
{
costs[i, j] = 200; // Moving cost.
}
}
}
}
return(costs);
}
// TODO(zhangshuai.ds): Pass in 3 policies.
public AssignerCore(Solver solver, AssignmentDescription assignment)
{
this.solver_ = solver ?? throw new ArgumentNullException(nameof(solver));
this.assignment_ = assignment ?? throw new ArgumentNullException(nameof(assignment));
this.costs_ = this.ComputeCosts(assignment);
this.variables_ = this.solver_.MakeBoolVarMatrix(assignment.Nodes.Count, assignment.Tasks.Count);
}
static void Main()
{
using var solver = Solver.CreateSolver(
"SimpleMipProgram",
"CBC_MIXED_INTEGER_PROGRAMMING");
var assigner = new Assigner(solver);
var assignment = new AssignmentDescription();
assignment.Nodes.Add(new NodeDescription
{
Id = 0,
CpuCores = int.MaxValue,
MemoryMiB = int.MaxValue,
});
for (int i = 1; i <= 3; i++)
{
assignment.Nodes.Add(new NodeDescription
{
Id = i,
CpuCores = 48,
MemoryMiB = 64 << 10, // 64 GiB
});
}
for (int i = 0; i < 13; i++)
{
assignment.Tasks.Add(new TaskDescription
{
Id = i,
CpuCores = 8,
MemoryMiB = 32 << 10, // 32 GiB, CPU:MEM=1:4
});
}
for (int i = 0; i < 17; i++)
{
assignment.Tasks.Add(new TaskDescription
{
Id = 13 + i,
CpuCores = 16,
MemoryMiB = 32 << 10, // 16 GiB, CPU:MEM=1:2
});
}
assignment.Assignments[0] = new HashSet <int>();
for (int i = 0; i < assignment.Tasks.Count; i++)
{
assignment.Assignments[0].Add(i);
}
for (int i = 1; i < assignment.Nodes.Count; i++)
{
assignment.Assignments[i] = new HashSet <int>();
}
assignment = assigner.Solve(assignment);
}
public AssignmentDescription Solve(AssignmentDescription assignment)
{
if (assignment is null)
{
throw new ArgumentNullException(nameof(assignment));
}
var assignerCore = new AssignerCore(this.solver_, assignment);
return(assignerCore.Run());
}
public AssignmentDescription Run()
{
this.AddObjective();
this.AddConstraints();
Solver.ResultStatus status = this.solver_.Solve();
if (status == Solver.ResultStatus.OPTIMAL)
{
var result = new AssignmentDescription();
foreach (NodeDescription n in this.assignment_.Nodes)
{
result.Nodes.Add(n);
}
foreach (TaskDescription t in this.assignment_.Tasks)
{
result.Tasks.Add(t);
}
for (int i = 1; i < this.assignment_.Nodes.Count; i++)
{
for (int j = 0; j < this.assignment_.Tasks.Count; j++)
{
if (this.variables_[i, j].SolutionValue() > 0)
{
if (!result.Assignments.TryGetValue(i, out ISet <int> tasks))
{
tasks = new HashSet <int>();
result.Assignments.Add(i, tasks);
}
tasks.Add(j);
Console.WriteLine($"Task {j} assigned to node {i} with cost {this.costs_[i, j]}.");
}
}
}
Console.WriteLine($"Total cost is {this.solver_.Objective().Value()}");
return(result);
}
throw new NotImplementedException($"Not implemented for status: {status}");
}