public int Evaluate(StateBase state, StateBase goalState)
{
return(Evaluate(state as T, goalState as T));
}
public Node Find(StateBase state)
{
return(_hashByState.ContainsKey(state) && _hashByState[state].Count > 0 ? _hashByState[state].First() : null);
}
public HeuristicCache(StateBase goal, IHeuristic heuristic)
{
_goal = goal;
_heuristic = heuristic;
_cache = new Dictionary <StateBase, int>();
}
public SearchResult GenericSearch(StateBase initialState,
StateBase goalState,
string algName,
NodeComparator comparator,
CostFunc cost,
IHeuristic heuristic,
int?depthLimit = null)
{
Frontier frontier = new Frontier(comparator);
Explored explored = new Explored();
HeuristicCache cache = new HeuristicCache(goalState, heuristic);
int nodesGenerated = 0;
int nodesPrevGenerated = 0;
Node initNode = new Node(initialState, cost, null, null, cache.Evaluate);
frontier.Push(initNode);
while (true)
{
if (frontier.Count == 0)
{
return(new SearchResult(null, nodesGenerated, nodesPrevGenerated, 0, explored.Count, algName, heuristic));
}
Node node = frontier.Pop();
explored.Push(node);
// goal test
if (node.State.Equals(goalState))
{
return(new SearchResult(node, nodesGenerated, nodesPrevGenerated, frontier.Count, explored.Count, algName, heuristic));
}
if (depthLimit != null && node.Depth == depthLimit)
{
continue;
}
IEnumerable <Node> children = node.Successors(cost, cache.Evaluate);
foreach (Node child in children)
{
nodesGenerated++;
// If this state is found in the Frontier, replace the old state with the new state if its GHat is smaller
Node foundInFrontier = frontier.Find(child.State);
if (foundInFrontier != null)
{
nodesPrevGenerated++;
if (foundInFrontier.GHat > child.GHat)
{
frontier.Replace(foundInFrontier, child);
}
}
else
{
Node foundInExplored = explored.Find(child.State);
// If this state is found in the Explored, replace the old state with the new state if its GHat is smaller
if (foundInExplored != null)
{
nodesPrevGenerated++;
if (foundInExplored.GHat > child.GHat)
{
explored.Remove(foundInExplored);
frontier.Push(child);
}
}
else
{
// doesn't exist in frontier or explored, adding to frontier.
frontier.Push(child);
}
}
}
}
}
public Searcher(StateBase initialState, StateBase goalState)
{
_initialState = initialState;
_goalState = goalState;
}
public Node Find(StateBase state)
{
return(state != null && _hashByState.ContainsKey(state) ? _hashByState[state] : null);
}
