// TODO: FIX THIS METHOD TO MATCH THE EDGE.ROW && EDGE.COLUMN!!
private LbDifferenceResult GetLbDifference(int row, int col, State state)
{
State includeState = new State(state);
State excludeState = new State(state);
_createdStates += 2;
includeState.Matrix = SetupIncludeMatrix(includeState.Matrix, row, col);
excludeState.Matrix = SetupExcludeMatrix(excludeState.Matrix, row, col);
includeState = DeleteEdges(includeState, row, col);
includeState = GenerateReducedMatrix(includeState);
excludeState = GenerateReducedMatrix(excludeState);
double lbDifference = excludeState.GetLowerBound() - includeState.GetLowerBound();
return(new LbDifferenceResult(includeState, excludeState, lbDifference, row, col));
}
public PathCalculation CalculatePath()
{
Stopwatch stopwatch = new Stopwatch();
stopwatch.Start();
while (pq.Count != 0)
{
if (stopwatch.Elapsed.Seconds >= 30)
{
break;
}
State state = pq.RemoveMin();
if (state.GetLowerBound() < _bssf)
{
LbDifferenceResult greatestDifferenceResult = CalculateGreatestLBDifference(state);
State[] children = new State[2]
{
greatestDifferenceResult.IncludeState, greatestDifferenceResult.ExcludeState
};
foreach (State child in children)
{
if (IsSolution(child))
{
bssfUpdates++;
_bssf = child.GetLowerBound();
_bestStateSoFar = child;
}
else if (child.GetLowerBound() < _bssf)
{
// Dividing by the number cities in the solution is a great way to prioritize those solutions
// that are further along. This helps the algorithm "dig deeper" into the search.
pq.Add((int)child.GetLowerBound() / (child.GetCitiesInSolution() == 0 ? 1 : child.GetCitiesInSolution()), child);
if (pq.Count > _maxStatesStored)
{
_maxStatesStored = pq.Count;
}
}
else
{
_prunedSates++;
}
}
}
else
{
_prunedSates++;
}
}
stopwatch.Stop();
Console.WriteLine("----------------------------------");
Console.WriteLine("Elapsed Time: " + stopwatch.ElapsedMilliseconds);
Console.WriteLine("Problem Size: " + _cities.Length);
Console.WriteLine("Max States: " + _maxStatesStored);
Console.WriteLine("Total Created: " + _createdStates);
Console.WriteLine("States Pruned: " + _prunedSates);
Console.WriteLine("----------------------------------");
return(GeneratePathResult(_bestStateSoFar, _cities, stopwatch.ElapsedMilliseconds));
}