public int RootAlphaBeta(int alpha, int beta, Board board, int depth)
{
Stopwatch s = new Stopwatch();
s.Start();
Board bCopy = board;
int[] moves = bCopy.GetInterestingMoves();
if (moves.Length == 0)
{
return((board.width * board.width) / 2);
}
int bestId = 0;
int color = board.blackTurn ? 1 : -1;
string deb = "";
for (int i = 0; i < moves.Length; i++)
{
bCopy = new Board(board);
bCopy.ChangeSquare(moves[i]);
bCopy.EndTurn();
int score = -AlphaBeta(-beta, -alpha, bCopy, depth - 1, color);
if (score > alpha)
{
alpha = score;
bestId = i;
deb += "Move: " + moves[i].ToString() + " has value " + score.ToString() + ".\n ";
}
}
s.Stop();
deb += "\n\n Execution took " + s.ElapsedMilliseconds.ToString() + " miliseconds.";
board.DebugWrite(deb);
return(moves[bestId]);
}
public int AlphaBetaOptimized(int alpha, int beta, Board b, int depth, int color, List <int> movesLast)
{
Board bCopy = b;
if (depth == 0)
{
return(EvaluateBoard(bCopy) * color);
}
List <int> moves;
if (movesLast != null)
{
moves = movesLast;
}
else
{
moves = new List <int>(bCopy.GetInterestingMoves());
}
for (int i = 0; i < moves.Count; i++)
{
bCopy = new Board(b);
if (bCopy.board[moves[i]] != 0)
{
continue;
}
bCopy.ChangeSquare(moves[i]);
color = bCopy.blackTurn ? -1 : 1;
int value = EvaluateBoard(bCopy) * color;
if (value > 9000)
{
return(-value * depth);
}
else if (value < -9000)
{
return(-value * depth);
}
bCopy.EndTurn();
List <int> movesCopy = new List <int>(moves);
int[] movesToAdd = FindNewMoves(bCopy, bCopy.lastMove);
for (int j = 0; j < movesToAdd.Length; j++)
{
if (!movesCopy.Contains(movesToAdd[j]))
{
movesCopy.Add(movesToAdd[j]);
}
}
int score = -AlphaBetaOptimized(-beta, -alpha, bCopy, depth - 1, color, movesCopy);
if (beta != -2147483648 && score >= beta)
{
return(beta);
}
if (score > alpha)
{
alpha = score;
}
}
return(alpha);
}
public void AlphaBetaFromMoves(Board board, int depth, int[] moves)
{
if (moves.Length == 0)
{
lock (locker){
results.Add(new KeyValuePair <int, int>(-1, -1));
}
return;
}
int alpha = int.MinValue;
int beta = int.MaxValue;
Board bCopy = board;
int bestId = 0;
int color = board.blackTurn ? 1 : -1;
for (int i = 0; i < moves.Length; i++)
{
bCopy = new Board(board);
bCopy.ChangeSquare(moves[i]);
bCopy.EndTurn();
int score;
if (depth > 5)
{
score = -AlphaBetaOptimized(-beta, -alpha, bCopy, depth - 1, color, null);
}
else
{
score = -AlphaBeta(-beta, -alpha, bCopy, depth - 1, color);
}
if (score > alpha)
{
alpha = score;
bestId = i;
}
}
lock (locker){
results.Add(new KeyValuePair <int, int>(moves[bestId], alpha));
}
}
public int[] FindMoves(Board state, int additionalDepth)
{
List <int> moves = new List <int>(state.GetInterestingMoves());
//Go through the moves and remove the real bad ones
for (int i = moves.Count - 1; i >= 0; i--)
{
Board copy = new Board(state);
int alpha = int.MinValue;
int beta = int.MaxValue;
copy.ChangeSquare(moves[i]);
copy.EndTurn();
int win = copy.CheckWin(copy.lastMove);
if ((win == 1 && state.blackTurn) || (win == 2 && !state.blackTurn))
{
return(new int[] { moves[i] });
}
int color = copy.blackTurn ? 1 : -1;
int value = AlphaBeta(alpha, beta, copy, additionalDepth, color);
//Console.WriteLine("move " + moves[i] + " val " + value);
//Console.Read();
if (value > 10000)
{
moves.RemoveAt(i);
}
else if (value < -10000)
{
return(new int[] { moves[i] });
}
}
if (moves.Count == 0)
{
return(state.GetInterestingMoves());
}
return(moves.ToArray());
}
public int AlphaBeta(int alpha, int beta, Board b, int depth, int color)
{
Board bCopy = b;
if (depth == 0)
{
return(EvaluateBoard(bCopy) * color);
}
int[] moves = bCopy.GetInterestingMoves();
for (int i = 0; i < moves.Length; i++)
{
bCopy = new Board(b);
bCopy.ChangeSquare(moves[i]);
color = bCopy.blackTurn ? -1 : 1;
int value = EvaluateBoard(bCopy) * color;
if (value > 9000)
{
return(-value * depth);
}
else if (value < -9000)
{
return(-value * depth);
}
bCopy.EndTurn();
int score = -AlphaBeta(-beta, -alpha, bCopy, depth - 1, color);
if (beta != -2147483648 && score >= beta)
{
return(beta);
}
if (score > alpha)
{
alpha = score;
}
}
return(alpha);
}
public int MonteCarloSearch(Board rootState, double searchTimer)
{
//Check if we can find a winning move in one move
string deb = "";
if (true)
{
int winCheck = GetHighestValueMove(rootState, 1);
if (winCheck == (rootState.width * rootState.width) / 2)
{
return((rootState.width * rootState.width) / 2);
}
Board copy = new Board(rootState);
copy.ChangeSquare(winCheck);
int value = rootState.blackTurn ? EvaluateBoard(copy) : -EvaluateBoard(copy);
deb += "Highest 1 ply value move is: " + winCheck.ToString() + ", value " + value.ToString() + ".\n ";
if (value > 9999)
{
rootState.DebugWrite(deb);
return(winCheck);
}
}
Node root = new Node(rootState.lastSquare, null, rootState, 1);
Stopwatch s = new Stopwatch();
s.Start();
while (s.Elapsed.Seconds < searchTimer)
{
Node node = root;
Board state = new Board(rootState);
//Select
while (node.untriedMoves.Count == 0 && node.nodes.Count != 0)
{
node = NodeSelection(node);
state.ChangeSquare(node.move);
state.EndTurn();
}
//Expand
if (node.untriedMoves.Count != 0)
{
int move = node.GetRandomMove();
state.ChangeSquare(move);
state.EndTurn();
node = node.AddChild(move, state);
}
//Rollout
int lastMove = node.move;
while (EvaluateBoard(state) == 0)
{
//int move = RootAlphaBeta(int.MinValue, int.MaxValue, state, 2);
int move = GetHighestValueMove(state, 1);
state.ChangeSquare(move);
state.EndTurn();
lastMove = move;
}
//Backpropagate
int result = state.CheckWin(lastMove);
while (node != null)
{
node.games++;
if (result == -1)
{
node.wins += 0.4;
}
else if ((result == 1 && rootState.blackTurn) || (result == 2 && !rootState.blackTurn))
{
node.wins += 1;
}
else
{
node.wins += 0;
}
node = node.parent;
}
}
int bestI = 0;
double bestValue = double.MinValue;
for (int i = 0; i < root.nodes.Count; i++)
{
double val = root.nodes[i].games * (root.nodes[i].wins / root.nodes[i].games);
if (val > bestValue)
{
deb += "Move: " + root.nodes[i].move.ToString() + " has Wins " + root.nodes[i].wins.ToString("0.0") + ", games " + root.nodes[i].games.ToString() + ", = " + (root.nodes[i].wins / root.nodes[i].games).ToString("0.000") + ".\n ";
bestI = i;
bestValue = val;
}
}
rootState.DebugWrite(deb);
//rootState.DebugWrite("Done finding move from " + root.nodes.Count.ToString() + " available.");
return(root.nodes[bestI].move);
}