public NodeState MakeChild(ref NodeState parentNode, int i)
{
//FROM and TO city indices
int cityCount = Cities.Length;
int fromCity = parentNode.GetLastCityInRouteIndex();
int toCity = i;
//Make a child matrix from parent
double[,] copyMatrix = CopyMatrix(parentNode.GetMatrix(), cityCount);
double[,] childMatrix = MakeChildMatrix(copyMatrix, fromCity, toCity);
//Inherit and add to lower bound for the child
double childLB = parentNode.GetLowerBound() + parentNode.GetMatrix()[toCity, fromCity];
//Inherit and add to route for the child
ArrayList childRoute = (ArrayList)parentNode.GetRoute().Clone();
childRoute.Add(Cities[toCity]);
//Inherit the cities already visited by the parent and add the city the child is going to be in.
List <bool> childCitiesVisited = CopyCitiesVisited(parentNode.GetCitiesVisited());
childCitiesVisited[toCity] = true;
return(new NodeState(childMatrix, childLB, childRoute, toCity, childCitiesVisited));
}
public void GenerateChildren(ref List <NodeState> queue, ref int MaxNodeStateAmount, ref int BSSFupdates, ref int TotalNodeStates, ref int TotalNodeStatesPrunned, int startCity)
{
int cityCount = Cities.Length;
//Get the first node in the priority
NodeState currentNodeState = DeletePriorityNode(ref queue);
//If the currentNodeState should be prunned
if (currentNodeState.GetLowerBound() >= bssf.costOfRoute())
{
currentNodeState = PruneTheQueue(ref queue, currentNodeState, ref TotalNodeStatesPrunned);
}
//Generate a child for each city the currentNodeState can go to.
for (int i = 0; i < cityCount; i++)
{
if (!currentNodeState.AlreadyVisited(i))
{
//Make a child
NodeState child = MakeChild(ref currentNodeState, i);
child.ReduceMatrixAndUpdateLowerBound(cityCount);
// Add to node states because a child was generated
TotalNodeStates++;
//If LB is less BSSF then add to queue, TNS++
if (child.GetLowerBound() < bssf.costOfRoute())
{
//Before adding to the queue, see if you have a new BSSF
if (BetterBSSFExists(ref child, startCity))
{
bssf = new TSPSolution(child.GetRoute());
BSSFupdates++;
}
else
{
//add node to the queue
if (!child.HasVisitedAllCities())
{
//Add
AddNodeToPriorityQueue(ref queue, child);
}
}
}
else
{
//Prune. We don't need to even visit it.
TotalNodeStatesPrunned++;
}
}
}
//Check the MaxNodeStates
CheckQueueSize(ref MaxNodeStateAmount, queue.Count - 1);
}
