static void Main(string[] args)
{
var knapsackData = new KnapsackData(50);
knapsackData.AddItem(new Item(10, 60));
knapsackData.AddItem(new Item(20, 120));
knapsackData.AddItem(new Item(20, 110));
knapsackData.AddItem(new Item(80, 150));
knapsackData.AddItem(new Item(40, 210));
knapsackData.AddItem(new Item(50, 100));
knapsackData.AddItem(new Item(10, 100));
knapsackData.AddItem(new Item(20, 100));
knapsackData.AddItem(new Item(90, 400));
Console.WriteLine("Starting processing...");
var sasolver = new SaSolver(3, 4000.0, 0.00001, 0.9999);
var solver = new KnapsackSolver(knapsackData, sasolver);
var solution = solver.GetSolution();
Console.WriteLine($"Result: taken time {solution.TakenTime}, picked items");
foreach (var item in solution.PickedItem)
{
Console.WriteLine($"item: weight {item.Weight}, value {item.Value}");
}
Console.WriteLine($"Result: gained value {solution.GainedValue}, gained weight {solution.GainedWeight}");
Console.ReadKey();
}
public Solution Solve(KnapsackData data)
{
_data = data;
long start = DateTime.UtcNow.Millisecond;
var current = new BinarySolution(data.AvailableItems.Count);
var best = current;
current.UpdateFitness(data, Alpha);
while (_temperature > _endingTemperature)
{
for (var m = 0; m < _samplingSize; m++)
{
current = GetNextState(current);
if (current.Fitness < best.Fitness)
{
best = current;
}
}
Cool();
}
long end = DateTime.UtcNow.Millisecond;
var pickedItem = GenerateSolution(data, best);
return(new Solution(pickedItem, end - start));
}
public List <Item> GenerateSolution(KnapsackData knapsackData, BinarySolution solution)
{
var pickedItem = new List <Item>();
for (var i = 0; i < knapsackData.AvailableItems.Count; i++)
{
if (solution.GetBit(i) == 1)
{
pickedItem.Add(knapsackData.AvailableItems[i]);
}
}
return(pickedItem);
}
public void UpdateFitness(KnapsackData data, double alpha)
{
double sumVal = 0, sumWeight = 0;
for (var i = 0; i < data.AvailableItems.Count; i++)
{
var item = data.AvailableItems[i];
if (GetBit(i) == 1)
{
sumWeight += item.Weight;
}
else
{
sumVal += item.Value;
}
}
var violation = Math.Max(sumWeight / data.MaxWeight - 1, 0);
Weight = sumWeight;
Fitness = sumVal + alpha * violation;
}
public KnapsackSolver(KnapsackData data, IKnapsackStrategy strategy)
{
_data = data;
_strategy = strategy;
}