public override IOperation Apply()
{
BinaryVector binaryVector = BinaryVectorParameter.ActualValue;
OneBitflipMove move = OneBitflipMoveParameter.ActualValue;
BinaryVector newSolution = new BinaryVector(binaryVector);
newSolution[move.Index] = !newSolution[move.Index];
DoubleValue quality = KnapsackEvaluator.Apply(newSolution,
KnapsackCapacityParameter.ActualValue,
PenaltyParameter.ActualValue,
WeightsParameter.ActualValue,
ValuesParameter.ActualValue).Quality;
double moveQuality = quality.Value;
if (MoveQualityParameter.ActualValue == null)
{
MoveQualityParameter.ActualValue = new DoubleValue(moveQuality);
}
else
{
MoveQualityParameter.ActualValue.Value = moveQuality;
}
return(base.Apply());
}
private void ParameterizeEvaluator()
{
if (Evaluator is KnapsackEvaluator)
{
KnapsackEvaluator knapsackEvaluator =
(KnapsackEvaluator)Evaluator;
knapsackEvaluator.BinaryVectorParameter.ActualName = SolutionCreator.BinaryVectorParameter.ActualName;
knapsackEvaluator.BinaryVectorParameter.Hidden = true;
knapsackEvaluator.KnapsackCapacityParameter.ActualName = KnapsackCapacityParameter.Name;
knapsackEvaluator.KnapsackCapacityParameter.Hidden = true;
knapsackEvaluator.WeightsParameter.ActualName = WeightsParameter.Name;
knapsackEvaluator.WeightsParameter.Hidden = true;
knapsackEvaluator.ValuesParameter.ActualName = ValuesParameter.Name;
knapsackEvaluator.ValuesParameter.Hidden = true;
knapsackEvaluator.PenaltyParameter.ActualName = PenaltyParameter.Name;
knapsackEvaluator.PenaltyParameter.Hidden = true;
}
}
public override IOperation Apply()
{
BinaryVector sol = CurrentScope.Variables[SolutionParameter.ActualName].Value as BinaryVector;
if (sol == null)
{
throw new ArgumentException("Cannot improve solution because it has the wrong type.");
}
// calculate value-to-weight ratio
double[] ratio = new double[Values.Length];
for (int i = 0; i < ratio.Length; i++)
{
ratio[i] = (double)Values[i] / (double)Weights[i];
}
// calculate order for ratio
int[] order = new int[ratio.Length];
foreach (var x in ratio.Select((x, index) => new { Value = x, ValueIndex = index })
.OrderByDescending(x => x.Value)
.Select((x, index) => new { ValueIndex = x.ValueIndex, ItemIndex = index }))
{
order[x.ItemIndex] = x.ValueIndex;
}
int evaluatedSolutions = 0;
int j = sol.Length - 1;
while (KnapsackEvaluator.Apply(sol, KnapsackCapacity, Penalty, Weights, Values)
.SumWeights.Value > KnapsackCapacity.Value && j >= 0)
{
sol[order[j--]] = false;
evaluatedSolutions++;
}
// calculate weight
int weight = 0;
for (int i = 0; i < sol.Length; i++)
{
if (sol[i])
{
weight += Weights[i];
}
}
// improve solution
bool feasible = true; j = 0;
while (feasible && j < sol.Length)
{
while (sol[order[j]])
{
j++;
}
if (weight + Weights[order[j]] <= KnapsackCapacity.Value)
{
sol[order[j]] = true;
weight += Weights[order[j]];
}
else
{
feasible = false;
}
evaluatedSolutions++;
}
CurrentScope.Variables[SolutionParameter.ActualName].Value = sol;
CurrentScope.Variables.Add(new Variable("LocalEvaluatedSolutions", new IntValue(evaluatedSolutions)));
return(base.Apply());
}
protected KnapsackEvaluator(KnapsackEvaluator original, Cloner cloner) : base(original, cloner)
{
}
protected KnapsackEvaluator(KnapsackEvaluator original, Cloner cloner) : base(original, cloner) { }
