public override Tuple <Point2D, Point2D> GetMove()
{
Stopwatch.Start();
var pieces = Board.GetAllColored(Color);
var possibleMoves = Board.GetAllPossibleMoves();
possibleMoves = possibleMoves.FindAll(tuple => tuple.Item1.Color == Color);
//var newGameMoves = game.ugly_moves();
var bestMove = _randomAi.GetMove();
//use any negative large number
var bestValue = BoardEvalMethod.GetEvalFunc(_boardEval).Invoke(Board, Color);
for (var i = 0; i < possibleMoves.Count; i++)
{
var newGameMove = possibleMoves[i];
var tmpBoard = Board.Clone();
tmpBoard.Move(newGameMove.Item1, newGameMove.Item2);
tmpBoard.Move(new RandomAI(tmpBoard, Util.ConverToOpposite(Color)).GetMove());
//take the negative as AI plays as black
var boardValue = BoardEvalMethod.GetEvalFunc(_boardEval).Invoke(tmpBoard, Color);
if (boardValue > bestValue)
{
bestValue = boardValue;
bestMove = new Tuple <Point2D, Point2D>(newGameMove.Item1.PositionPoint2D, newGameMove.Item2);
}
}
_stopwatch.Stop();
return(bestMove);
}
/*
* function alphabeta(node, depth, α, β, maximizingPlayer)
* 02 if depth = 0 or node is a terminal node
* 03 return the heuristic value of node
* 04 if maximizingPlayer
* 05 v := -∞
* 06 for each child of node
* 07 v := max(v, alphabeta(child, depth – 1, α, β, FALSE))
* 08 α := max(α, v)
* 09 if β ≤ α
* 10 break (* β cut-off *)
* 11 return v
* 12 else
* 13 v := +∞
* 14 for each child of node
* 15 v := min(v, alphabeta(child, depth – 1, α, β, TRUE))
* 16 β := min(β, v)
* 17 if β ≤ α
* 18 break (* α cut-off *)
* 19 return v
*
* alphabeta(origin, depth, -∞, +∞, TRUE)
*
*/
private float AlpaBetaMinimax(Node node, float alpha, float beta, int depth, Color color)
{
if (depth == 0 || Rules.GameFinished(node.Board))
{
if (Rules.CheckCheckMate(node.Board))
{
node.Score = color == Color ? 1000 : -1000;
}
else
{
node.Score = BoardEvalMethod.GetEvalFunc(_boardEval).Invoke(node.Board, Color);
}
return(node.Score);
}
if (color == Color)
{
var v = -float.MaxValue;
foreach (var childNode in node.GenerateChildNodes())
{
v = Math.Max(v, AlpaBetaMinimax(childNode, alpha, beta, depth - 1, Util.ConverToOpposite(color)));
alpha = Math.Max(v, alpha);
node.Score = alpha;
if (beta <= alpha)
{
break;
}
}
return(v);
}
else
{
var v = float.MaxValue;
foreach (var childNode in node.GenerateChildNodes())
{
v = Math.Min(v, AlpaBetaMinimax(childNode, alpha, beta, depth - 1, Util.ConverToOpposite(color)));
beta = Math.Min(v, beta);
node.Score = beta;
if (beta <= alpha)
{
;
break;
}
}
return(v);
}
}
public Node[] GenerateChildNodes()
{
var list = new List <Node>();
foreach (var allPossibleMove in Organize(Board.GetAllPossibleMoves(Color),
BoardEvalMethod.GetEvalFunc(BoardEval)))
{
var newBoard = Board.Clone();
newBoard.Move(allPossibleMove);
list.Add(new Node(this,
new Pair <Point2D, Point2D>(allPossibleMove.Item1.PositionPoint2D, allPossibleMove.Item2), newBoard,
Depth - 1, BoardEval));
}
childerNodes = list;
return(list.ToArray());
}
