/**
* @param k knapsack to find a solution for
* @return new knapsack with a random solution
*/
knapsack randomSolution(knapsack &k)
{
int i = 0;
while (checkValid(k) && i < k.getNumObjects())
{
int random = rand() % 2;
if (random == 1 && (k.getCost() + k.getCost(i)) < k.getCostLimit())
k.select(i);
else
k.unSelect(i);
i++;
}
return k;
}
/**
* Finds a local optimum and returns the result
*
* @param k knapsack to find local optimum for
* @param int 2-opt or 3-opt
* @return new knapsack with a local opt solution
*/
knapsack localOptimum(knapsack &k, int opt)
{
knapsack original(k);
deque<knapsack> problem;
knapsack bestFound = knapsack(k);
try
{
for (int l = 0; l < k.getNumObjects() - 1; l++)
{
k = knapsack(original);
if (!k.isSelected(l))
continue;
k.unSelect(l);
for (int m = l; m < k.getNumObjects() - 1; m++)
{
if (!k.isSelected(m))
continue;
k.unSelect(m);
if (opt == 3)
{
for (int n = m; n < k.getNumObjects() - 1; n++)
{
if (!k.isSelected(n))
continue;
k.unSelect(n);
problem.push_front(knapsack(k));
}
}
else
problem.push_front(knapsack(k));
}
}
while(problem.size() > 0)
{
checkTimeLimit();
knapsack current = problem.front();
problem.pop_front();
deque<knapsack> solution;
solution.push_front(knapsack(current));
int currentIndex = 0;
while(solution.size() > 0)
{
knapsack currentSolution = solution.front();
solution.pop_front();
if (currentSolution.getValue() > bestFound.getValue())
{
bestFound = knapsack(currentSolution);
}
if (currentIndex < currentSolution.getNumObjects() - 1)
{
if (!currentSolution.isSelected(currentIndex) &&
(currentSolution.getCost() + currentSolution.getCost(currentIndex)) < currentSolution.getCostLimit())
{
currentSolution.select(currentIndex);
solution.push_front(knapsack(currentSolution));
}
currentIndex++;
}
}
}
return bestFound;
}
catch (baseException &ex)
{
cout << ex.what() << endl;
return bestFound;
}
} //end localOptimum
