public ISpace ConstructSpace()
{
Stack<ISpaceCandidate> stack = new Stack<ISpaceCandidate>();
HashSet<int> closedList = new HashSet<int>();
//Dictionary<int, ISpaceCandidate> debugClosedList = new Dictionary<int, ISpaceCandidate>();
int nodesExplored = 0;
int dupesRemoved = 0;
SpaceCandidate initialCandidate = new SpaceCandidate(m_mission);
stack.Push(initialCandidate);
while (stack.Count > 0)
{
ISpaceCandidate curNode = stack.Pop();
nodesExplored++;
if (curNode.IsComplete)
{
return curNode.Space;
}
List<ISpaceCandidate> successors = curNode.Expand();
foreach (ISpaceCandidate successor in successors)
{
/*
* Tests if we ever have a hash collision when spaces aren't identical.
* I tried a couple dozen times and never had this occur.
if (closedList.Contains(curNode.GetHashCode()) &&
!SpaceImpl.TestAreEqual((SpaceImpl)curNode.Space, (SpaceImpl)debugClosedList[curNode.GetHashCode()].Space))
{
// debug me!
SpaceImpl a = (SpaceImpl)curNode.Space;
SpaceImpl b = (SpaceImpl)debugClosedList[curNode.GetHashCode()].Space;
int c = 7;
}
*/
if (!closedList.Contains(successor.GetHashCode()))
{
closedList.Add(successor.GetHashCode());
//debugClosedList.Add(successor.GetHashCode(), curNode);
stack.Push(successor);
}
else
{
dupesRemoved++;
}
}
}
return null;
}
public ISpace ConstructSpace()
{
PriorityQueue<ISpaceCandidate, float> openList = new PriorityQueue<ISpaceCandidate, float>();
HashSet<int> closedList = new HashSet<int>();
SpaceCandidate initialCandidate = new SpaceCandidate(m_mission);
openList.Enqueue(initialCandidate, 0.0f);
while (openList.Count > 0)
{
ISpaceCandidate curNode = openList.Dequeue().Value;
// closedList simply checks the hash. yes, its possible that then we'll get a false
// positive later because two things hash to the same value. i dont want to impl
// a more rigorous Equals function and use a dict, so i'm hoping that these false
// positives are minimal given the 4 billion possible hash values.
if (closedList.Contains(curNode.GetHashCode()))
{
continue;
}
closedList.Add(curNode.GetHashCode());
if (curNode.IsComplete)
{
return curNode.Space;
}
foreach (ISpaceCandidate successor in curNode.Expand())
{
float cost = successor.Cost;
float heuristic = m_heuristic(successor);
openList.Enqueue(successor, 1000000 - (cost + heuristic));
}
}
return null;
}
protected SpaceCandidate DeepCopy()
{
SpaceCandidate copy = new SpaceCandidate();
copy.m_cost = this.m_cost;
copy.m_space = this.m_space.DeepCopy();
copy.m_mission = this.m_mission.DeepCopy();
// TODO
// should only be removed once this class is finalized for testing.
// so we don't have obscure bugs caused by forgetting to copy a new field
// which was added later.
//throw new NotImplementedException();
return copy;
}
