private double CalcDifference(Variation solution, double sumWeightItem)
{
double difference = 0;
foreach (Knapsack knapsack in solution.Knapsacks)
{
double knapsackWeightSum = knapsack.Items.Sum(i => i.Weight);
difference += Math.Abs(knapsackWeightSum - sumWeightItem);
}
return difference;
}
public void AddKnapsack(Variation currentVariation, List<Knapsack> knapsacks)
{
if (currentVariation.Knapsacks == null)
{
currentVariation.Knapsacks = new List<Knapsack>();
}
foreach (var knapsack in knapsacks)
{
currentVariation.Knapsacks.Add(new Knapsack {Capacity = knapsack.Capacity, Items = new List<Item>(), Id = knapsack.Id});
}
}
private static bool IsKnapsackAcceptables(Variation currentVariation)
{
bool acceptables = true;
foreach (Knapsack knapsack in currentVariation.Knapsacks)
{
if (knapsack.Capacity < knapsack.Items.Sum(i => i.Weight))
{
acceptables = false;
}
}
return acceptables;
}
public Variation FillFromSequence(Variation variation, List<Item> items, bool[] sequence)
{
int knapsackIndx = 0;
int itemIndx = 0;
foreach (var s in sequence)
{
if (knapsackIndx == variation.Knapsacks.Count)
{
knapsackIndx = 0;
itemIndx++;
}
if (s)
{
variation.Knapsacks[knapsackIndx].Items.Add(new Item { Id = items[itemIndx].Id, Weight = items[itemIndx].Weight });
}
knapsackIndx++;
}
return variation;
}
public Result TryCalculate()
{
int variationsCount = GetVariationsCount();
double gMin = Double.MaxValue;
var result = new Result {Acceptables = new List<Variation>(), ItemsCount = _calculate.Items.Count};
var dtStart = DateTime.Now;
for (int i = 0; i < variationsCount; i++)
{
var currentVariation = new Variation();
_variationManager.AddKnapsack(currentVariation, _calculate.Knapsacks);
_variationManager.FillFromSequence(currentVariation, _calculate.Items, SequenceHelper.GetSequence(i));
if (IsOneItemInKnapsack(currentVariation, _calculate.Items)
&& IsKnapsackAcceptables(currentVariation))
{
double sumWeightItem = _calculate.Items.Sum(item => item.Weight) / _calculate.Knapsacks.Count;
currentVariation.G = CalcDifference(currentVariation, sumWeightItem);
result.Acceptables.Add(currentVariation);
if (currentVariation.G < gMin)
{
result.Optimal = currentVariation;
gMin = currentVariation.G;
}
if (_calculate.CalculateError > 0
&& IsAcceptablesCalculateError(currentVariation.G, _calculate.CalculateError, sumWeightItem))
{
break;
}
}
}
result.RunTime = new TimeSpan(DateTime.Now.Ticks-dtStart.Ticks).TotalMilliseconds;
return result;
}
private bool IsOneItemInKnapsack(Variation currentVariation, IEnumerable<Item> items)
{
foreach (Item item in items)
{
int use = 0;
foreach (Knapsack knapsack in currentVariation.Knapsacks)
{
use += knapsack.Items.Count(i => i.Id == item.Id);
}
if (use > 1)
{
return false;
}
}
return true;
}