private void InitializeNode(GAAStarNode node)
{
Debug.Assert(node.search <= n_searches);
if (node.search != n_searches && node.search != 0)
{
Debug.Assert(path_cost.Count > node.search && node.h != INFINITY_INT);
if (node.g != INFINITY_INT && node.g + node.h < path_cost[node.search])
{
node.h = path_cost[node.search] - node.g;
}
Debug.Assert(delta_h.Count > n_searches && delta_h.Count > node.search);
int aux = node.h - (delta_h[n_searches] - delta_h[node.search]);
node.h = Math.Max(heuristic.DistanceToGoal(node.GetMazeCell(), goal.GetMazeCell()), (aux < 0 ? 0 : aux));
Debug.Assert(node.h >= 0);
node.g = INFINITY_INT;
}
else if (node.search == 0)
{
node.g = INFINITY_INT;
node.h = heuristic.DistanceToGoal(node.GetMazeCell(), goal.GetMazeCell());
}
node.search = n_searches;
}
public GAAStarLazy(Maze maze, bool mark_path, bool step_by_step,
TieBreakingStrategy tie_breaking_strategy, Heuristic heuristic, int neighborhood)
{
h = maze.GetH();
w = maze.GetW();
open_list = new BinaryHeap(w * h);
graph = new GAAStarNode[h, w];
for (int y = 0; y < h; y++)
{
for (int x = 0; x < w; x++)
{
graph[y, x] = new GAAStarNode(maze.GetMazeCell(x, y), tie_breaking_strategy);
//مقدار کشف کننده فعلاً تعیین نمیشود
}
}
this.heuristic = heuristic;
this.mark_path = mark_path;
this.step_by_step = step_by_step;
this.neighborhood = neighborhood;
goal = graph[maze.GetGoal().Y, maze.GetGoal().X];
start = graph[maze.GetStart().Y, maze.GetStart().X];
new_goal = null;
path_cost_last_execution = n_searches = 0;
unblocked_cells = null;
piece_of_pseudo_code_being_executed = PieceOfPseudoCode.Null;// null;
delta_h = new List <int>();
path_cost = new List <int>();
delta_h.Add(0); /* delta_h(0) := 0 */
path_cost.Add(0); /* path_cost(0) := 0 */
}
public void Solve()
{
has_solution = false;
has_execution_finished = false;
Debug.Assert(path_cost_last_execution != INFINITY_INT);
{
/* If the goal changed update the heuristic. */
if (piece_of_pseudo_code_being_executed == PieceOfPseudoCode.Null)
{
if (new_goal != null)
{
Debug.Assert(path_cost.Count > n_searches);
InitializeNode(new_goal);
if (new_goal.g != INFINITY_INT && new_goal.g + new_goal.h < path_cost[n_searches])
{
new_goal.h = path_cost[n_searches] - new_goal.g;
}
delta_h.Add(delta_h[n_searches] + new_goal.h);
goal = new_goal;
new_goal = null;
}
else
{
delta_h.Add(delta_h[n_searches]);
}
n_searches++;
open_list.Clear();
}
/* If some cell became unblocked. */
if (unblocked_cells != null)
{
Debug.Assert(piece_of_pseudo_code_being_executed == PieceOfPseudoCode.Null ||
piece_of_pseudo_code_being_executed == PieceOfPseudoCode.PIECE_3A_9A ||
piece_of_pseudo_code_being_executed == PieceOfPseudoCode.PIECE_10A_17A);
if (piece_of_pseudo_code_being_executed != PieceOfPseudoCode.PIECE_10A_17A)
{
piece_of_pseudo_code_being_executed = PieceOfPseudoCode.PIECE_3A_9A;
for (IEnumerator i = unblocked_cells.GetEnumerator(); i.MoveNext() != false;)
//for (Iterator<MazeCell> i = unblocked_cells.iterator(); i.hasNext(); )
{
Cell maze_cell = (Cell)i.Current;//i.next();
//i.remove();
GAAStarNode node = graph[maze_cell.Y, maze_cell.X];
InitializeNode(node);
int cost = node.GetMazeCell().GetCost();
Debug.Assert(!node.GetMazeCell().IsBlocked());
for (int j = 0; j < neighborhood; j++)
{
int x, y;
x = node.GetMazeCell().X + Maze.delta_x[j];
y = node.GetMazeCell().Y + Maze.delta_y[j];
if (0 <= x && x < w && 0 <= y && y < h)
{
GAAStarNode predecessor = graph[y, x];
InitializeNode(predecessor);
if (predecessor.h > cost + node.h)
{
predecessor.h = cost + node.h;
predecessor.f = predecessor.h;
open_list.Insert(predecessor);
}
}
}
if (step_by_step)
{
return;
}
}
}
piece_of_pseudo_code_being_executed = PieceOfPseudoCode.PIECE_10A_17A;
while (open_list.Size() > 0)
{
GAAStarNode node = (GAAStarNode)open_list.Pop();
int cost = node.GetMazeCell().GetCost();
for (int i = 0; i < neighborhood; i++)
{
int x, y;
x = node.GetMazeCell().X + Maze.delta_x[i];
y = node.GetMazeCell().Y + Maze.delta_y[i];
if (0 <= x && x < w && 0 <= y && y < h)
{
GAAStarNode predecessor = graph[y, x];
if (predecessor == goal)
{
continue;
}
InitializeNode(predecessor);
if (predecessor.h > cost + node.h)
{
predecessor.h = cost + node.h;
predecessor.f = predecessor.h;
open_list.Insert(predecessor);
}
}
}
if (step_by_step)
{
return;
}
}
unblocked_cells = null;
}
}
/* A*. */
if (piece_of_pseudo_code_being_executed != PieceOfPseudoCode.PIECE_12_21)
{
InitializeNode(start);
InitializeNode(goal);
start.g = start.GetMazeCell().GetCost();
start.parent = null;
start.f = start.g + start.h;
open_list.Insert(start);
piece_of_pseudo_code_being_executed = PieceOfPseudoCode.PIECE_12_21;
if (step_by_step)
{
return;
}
}
while (open_list.Size() > 0 && goal.g > ((GAAStarNode)open_list.Peek()).f)
{
GAAStarNode node = (GAAStarNode)open_list.Pop();
for (int i = 0; i < neighborhood; i++)
{
int x, y;
x = node.GetMazeCell().X + Maze.delta_x[i];
y = node.GetMazeCell().Y + Maze.delta_y[i];
if (0 <= x && x < w && 0 <= y && y < h)
{
GAAStarNode child = graph[y, x];
if (child.GetMazeCell().IsBlocked())
{
continue;
}
InitializeNode(child);
int cost = child.GetMazeCell().GetCost();
if (node.g != INFINITY_INT && child.g > node.g + cost)
{
child.parent = node;
child.g = node.g + cost;
child.f = child.g + child.h;
open_list.Insert(child);
}
}
}
if (step_by_step)
{
return;
}
}
if (open_list.Size() != 0)
{
GAAStarNode node = goal, node_child = null;
path_cost_last_execution = node.g;
has_solution = true;
if (mark_path)
{
node.GetMazeCell().SetNextMazeCell(null);
node.GetMazeCell().SetPathFlag();
node_child = node;
node = node.parent;
while (node != null)
{
node.GetMazeCell().SetNextMazeCell(node_child.GetMazeCell());
node.GetMazeCell().SetPathFlag();
node_child = node;
node = node.parent;
}
}
}
if (has_solution)
{
path_cost.Add(path_cost_last_execution);
}
else
{
path_cost.Add(INFINITY_INT);
}
piece_of_pseudo_code_being_executed = PieceOfPseudoCode.Null;
has_execution_finished = true;
}