// Mutate a tour using swap mutation
private static void mutate(Knapsack sac)
{
Random rnd = new Random();
// Loop through tour cities
for (int i = 0; i < sac.getObjects().Length; i++)
{
// Apply mutation rate
if (rnd.NextDouble() < mutationRate)
{
// Get a second random position in the tour
int mutationPos = (int)(sac.getObjects().Length *rnd.NextDouble());
if (sac.getObjects()[mutationPos])
{
sac.setoneObject(i, false);
sac.processValue();
sac.processWeight();
}
else
{
if (sac.getWeight() + MainForm.listItems[i].Weight <= sac.getCapacity())
{
sac.setoneObject(i, true);
sac.processValue();
sac.processWeight();
}
}
}
}
}
// Applies crossover to a set of parents and creates offspring
public static Knapsack crossover(Knapsack parent1, Knapsack parent2)
{
Random rnd = new Random();
// Create new child tour
Knapsack child = new Knapsack();
// Get start and end sub tour positions for parent1's tour
int crossPos = (int)(rnd.NextDouble() * parent1.getObjects().Length);
// Loop and add the sub tour from parent1 to our child
for (int i = 0; i < child.getObjects().Length; i++)
{
if (i < crossPos)
{
child.processWeight();
if (child.getWeight() + MainForm.listItems[i].Weight <= child.getCapacity())
{
child.setoneObject(i, parent2.getoneObject(i));
child.processWeight();
}
}
else
{
child.processWeight();
if (child.getWeight() + MainForm.listItems[i].Weight <= child.getCapacity())
{
child.setoneObject(i, parent1.getoneObject(i));
child.processWeight();
}
}
}
child.processValue();
return(child);
}