public IBestMoveResult BestMove(Board board, SearchConfig config, MoveTimer timer, CancellationToken cancelToken)
{
_config = config;
_timer = timer;
_numNodesQuiessenceSearched = 0;
return BestMoveInternal(board, _config.DepthLimit, int.MinValue, int.MaxValue, cancelToken);
}
// constructors
public SearchConfig(SearchConfig toCopy)
{
DepthLimit = toCopy.DepthLimit;
PercentTimeLeftToIncrementDepthLimit = toCopy.PercentTimeLeftToIncrementDepthLimit;
ReportStatistics = toCopy.ReportStatistics;
MoveTimeout = toCopy.MoveTimeout;
GameMode = toCopy.GameMode;
_beginningHeuristic = toCopy._beginningHeuristic;
_middleHeuristic = toCopy._middleHeuristic;
_endHeuristic = toCopy._endHeuristic;
}
public IBestMoveResult BestMove(Board board, SearchConfig config, MoveTimer timer, CancellationToken cancelToken)
{
// initialize stats
_config = config;
_timer = timer;
_nodesGeneratedByDepth = Enumerable.Range(1, _config.DepthLimit).ToDictionary(x => x, x => 0);
_numNodesAtDepthLimit = 0;
_numNodesQuiessenceSearched = 0;
var result = BestMoveInternal(board, _config.DepthLimit, int.MinValue, int.MaxValue, cancelToken);
// fill stats
result.Config = _config;
result.NumNodesAtDepthLimit = _numNodesAtDepthLimit;
result.NodesGeneratedByDepth = _nodesGeneratedByDepth;
result.NumNodesQuiessenceSearched = _numNodesQuiessenceSearched;
result.TimedOut = _timedOut;
return result;
}
public IBestMoveResult BestMove(Board board, SearchConfig config, MoveTimer timer, CancellationToken cancelToken)
{
// initialize stats
_config = config;
_timer = timer;
_nodesGeneratedByDepth = Enumerable.Range(1, _config.DepthLimit).ToDictionary(x => x, x => 0);
_numNodesAtDepthLimit = 0;
_numNodesQuiessenceSearched = 0;
var result = BestMoveInternal(board, _config.DepthLimit, int.MinValue, int.MaxValue, cancelToken);
// fill stats
result.Config = _config;
result.NumNodesAtDepthLimit = _numNodesAtDepthLimit;
result.NodesGeneratedByDepth = _nodesGeneratedByDepth;
result.NumNodesQuiessenceSearched = _numNodesQuiessenceSearched;
result.TimedOut = _timedOut;
return(result);
}
// get alpha-beta configuration
private static SearchConfig GetConfig()
{
Console.WriteLine("Enter timeout in seconds: ");
var input = Console.ReadLine();
SearchConfig cfg = null;
while (cfg == null)
{
try
{
cfg = new SearchConfig(input);
}
catch
{
Console.WriteLine("Please enter a valid timeout: ");
input = Console.ReadLine();
}
}
return(cfg);
}
// get alpha-beta configuration
private static SearchConfig GetConfig()
{
Console.WriteLine("Enter timeout in seconds: ");
var input = Console.ReadLine();
SearchConfig cfg = null;
while (cfg == null)
{
try
{
cfg = new SearchConfig(input);
}
catch
{
Console.WriteLine("Please enter a valid timeout: ");
input = Console.ReadLine();
}
}
return cfg;
}
public IBestMoveResult BestMove(Board board, SearchConfig config, MoveTimer timer, CancellationToken cancelToken)
{
_timer = timer;
_cancelToken = cancelToken;
if (_isWalledOff)
{
var longestPath = NextMoveOnLongestPath(board, board.PlayerToMove);
return(new BestMoveResult(longestPath.Item1, longestPath.Item2));
}
else // otherwise fall back to alpha beta
{
var ab = new AlphaBeta().BestMove(board, config, timer, cancelToken);
// but if alpha beta thinks we'll lose, do longest move
if (ab.Score == int.MinValue)
{
var longestPath = NextMoveOnLongestPath(board, board.PlayerToMove);
return(new BestMoveResult(longestPath.Item1, longestPath.Item2));
}
return(ab);
}
}
public BoardSpace GetMyNextMove(Board board)
{
// start the timer
MoveTimer.I.StartTimer();
// cancel all tasks that are now irrelevant
foreach (var task in _tasksByOpponentMove.Where(x => !x.Key.Equals(board.LastMove)))
{
task.Value.CancelSource.Cancel();
}
TimeSpan?asyncTimeElapsed = null;
IBestMoveResult bestMoveResult;
if (board.LastMove == null || !_tasksByOpponentMove.ContainsKey(board.LastMove))
{
// we were not precomputing this path, so we need to start fresh
bestMoveResult = MoveGetter().BestMove(board, _config, MoveTimer.I, new CancellationToken());
}
else
{
// we already started down this branch, so use the result from the task
bestMoveResult = _tasksByOpponentMove[board.LastMove].BestMoveTask.Result;
// check how long that took us
asyncTimeElapsed = _tasksByOpponentMove[board.LastMove].Timer.GetTimeElapsed();
}
// stop timer and grab timer stats
var percentRemaining = MoveTimer.I.GetPercentOfTimeRemaining();
var elapsed = MoveTimer.I.GetTimeElapsed();
var timedOut = MoveTimer.I.Timeout();
MoveTimer.I.ResetTimer();
// report stats, for debugging only, will be off in production
if (_config.ReportStatistics)
{
Console.WriteLine("Time Taken (s): " + elapsed.TotalSeconds);
Console.WriteLine("Time Left (%): " + percentRemaining * 100);
if (asyncTimeElapsed != null)
{
Console.WriteLine("Async Time Taken (s): " + asyncTimeElapsed.Value.TotalSeconds);
}
Console.WriteLine(bestMoveResult.ToString());
}
// if we have enough time remaining, increase the depth limit
if (percentRemaining > _config.PercentTimeLeftToIncrementDepthLimit)
{
// if we didn't do the search async, just increase depth
if (asyncTimeElapsed == null)
{
_config.DepthLimit++;
}
else
{
// only increase depth if async time was decent
var asyncPercentTimeLeft = (_config.MoveTimeout.TotalMilliseconds - asyncTimeElapsed.Value.TotalMilliseconds) / _config.MoveTimeout.TotalMilliseconds;
if (asyncPercentTimeLeft > _config.PercentTimeLeftToIncrementDepthLimit / 2)
{
_config.DepthLimit++;
}
}
}
// if we timed out, decrease depth limit so we stop shooting ourself in the foot
if (timedOut)
{
_config.DepthLimit--;
}
var emptySpaces = board.GetEmptySpacesRemaining();
// figure out where we are in the game
if (_config.GameMode == GameMode.Beginning)
{
if (emptySpaces <= 40)
{
_config.DepthLimit--;
_config.GameMode = GameMode.Middle;
}
}
else if (_config.GameMode == GameMode.Middle && !timedOut)
{
// find out what our areas look like
var boardPostMove = board.Copy().Move(bestMoveResult.Move);
var myArea = OpenAreaHeuristic.GetOpenArea(boardPostMove, boardPostMove.MyPlayer);
var oppArea = OpenAreaHeuristic.GetOpenArea(boardPostMove, boardPostMove.OpponentPlayer);
// if we are walled off, switch to end game
if (myArea.All(x => !oppArea.Contains(x)))
{
_isWalledOff = true;
_config.GameMode = GameMode.End;
}
else // we aren't walled off
{
// if it's time for end game, switch and max out depth
if (emptySpaces <= 28)
{
_config.DepthLimit = 30;
_config.GameMode = GameMode.End;
}
// if we think we're going to lose, try to find our best move b/c alpha-beta will pick a random one
else if (bestMoveResult.Score == int.MinValue)
{
var tasksByDepthLimit = new Dictionary <int, AsyncSearchTask>();
// simultaneously search at smaller depths to get our best move that isn't -infinity
for (var newDepthLimit = _config.DepthLimit - 1; newDepthLimit > _config.DepthLimit / 2; newDepthLimit--)
{
var newConfig = new SearchConfig(_config)
{
DepthLimit = newDepthLimit
};
// new task with timeout set at our remaining time
var task = new AsyncSearchTask(_config.MoveTimeout.Subtract(elapsed));
task.BestMoveTask = Task.Factory.StartNew(() =>
{
task.Timer.StartTimer();
var result = MoveGetter().BestMove(board, newConfig, task.Timer, task.CancelSource.Token);
task.Timer.StopTimer();
return(result);
}, task.CancelSource.Token);
tasksByDepthLimit[newDepthLimit] = task;
}
foreach (var kvp in tasksByDepthLimit.OrderBy(x => x.Key))
{
var newBestMove = kvp.Value.BestMoveTask.Result;
// if we think we're going to lose or we timed out, cancel all deeper tasks because they will also think we're going to lose
if (newBestMove.Score == int.MinValue || kvp.Value.Timer.Timeout())
{
var kvpClosure = kvp;
foreach (var task in tasksByDepthLimit.Where(x => x.Key > kvpClosure.Key).Select(x => x.Value).Where(x => !x.BestMoveTask.IsCompleted))
{
task.CancelSource.Cancel();
}
break;
}
// if we found a better move, use it
if (newBestMove.Score > bestMoveResult.Score)
{
bestMoveResult = newBestMove;
}
}
}
}
}
return(bestMoveResult.Move);
}
public IBestMoveResult BestMove(Board board, SearchConfig config, MoveTimer timer, CancellationToken cancelToken)
{
_timer = timer;
_cancelToken = cancelToken;
if (_isWalledOff)
{
var longestPath = NextMoveOnLongestPath(board, board.PlayerToMove);
return new BestMoveResult(longestPath.Item1, longestPath.Item2);
}
else // otherwise fall back to alpha beta
{
var ab = new AlphaBeta().BestMove(board, config, timer, cancelToken);
// but if alpha beta thinks we'll lose, do longest move
if (ab.Score == int.MinValue)
{
var longestPath = NextMoveOnLongestPath(board, board.PlayerToMove);
return new BestMoveResult(longestPath.Item1, longestPath.Item2);
}
return ab;
}
}
public BoardSpace GetMyNextMove(Board board)
{
// start the timer
MoveTimer.I.StartTimer();
// cancel all tasks that are now irrelevant
foreach (var task in _tasksByOpponentMove.Where(x => !x.Key.Equals(board.LastMove)))
{
task.Value.CancelSource.Cancel();
}
TimeSpan? asyncTimeElapsed = null;
IBestMoveResult bestMoveResult;
if (board.LastMove == null || !_tasksByOpponentMove.ContainsKey(board.LastMove))
{
// we were not precomputing this path, so we need to start fresh
bestMoveResult = MoveGetter().BestMove(board, _config, MoveTimer.I, new CancellationToken());
}
else
{
// we already started down this branch, so use the result from the task
bestMoveResult = _tasksByOpponentMove[board.LastMove].BestMoveTask.Result;
// check how long that took us
asyncTimeElapsed = _tasksByOpponentMove[board.LastMove].Timer.GetTimeElapsed();
}
// stop timer and grab timer stats
var percentRemaining = MoveTimer.I.GetPercentOfTimeRemaining();
var elapsed = MoveTimer.I.GetTimeElapsed();
var timedOut = MoveTimer.I.Timeout();
MoveTimer.I.ResetTimer();
// report stats, for debugging only, will be off in production
if (_config.ReportStatistics)
{
Console.WriteLine("Time Taken (s): " + elapsed.TotalSeconds);
Console.WriteLine("Time Left (%): " + percentRemaining * 100);
if (asyncTimeElapsed != null)
{
Console.WriteLine("Async Time Taken (s): " + asyncTimeElapsed.Value.TotalSeconds);
}
Console.WriteLine(bestMoveResult.ToString());
}
// if we have enough time remaining, increase the depth limit
if (percentRemaining > _config.PercentTimeLeftToIncrementDepthLimit)
{
// if we didn't do the search async, just increase depth
if (asyncTimeElapsed == null)
{
_config.DepthLimit++;
}
else
{
// only increase depth if async time was decent
var asyncPercentTimeLeft = (_config.MoveTimeout.TotalMilliseconds - asyncTimeElapsed.Value.TotalMilliseconds) / _config.MoveTimeout.TotalMilliseconds;
if (asyncPercentTimeLeft > _config.PercentTimeLeftToIncrementDepthLimit/2)
{
_config.DepthLimit++;
}
}
}
// if we timed out, decrease depth limit so we stop shooting ourself in the foot
if (timedOut)
{
_config.DepthLimit--;
}
var emptySpaces = board.GetEmptySpacesRemaining();
// figure out where we are in the game
if (_config.GameMode == GameMode.Beginning)
{
if (emptySpaces <= 40)
{
_config.DepthLimit--;
_config.GameMode = GameMode.Middle;
}
}
else if (_config.GameMode == GameMode.Middle && !timedOut)
{
// find out what our areas look like
var boardPostMove = board.Copy().Move(bestMoveResult.Move);
var myArea = OpenAreaHeuristic.GetOpenArea(boardPostMove, boardPostMove.MyPlayer);
var oppArea = OpenAreaHeuristic.GetOpenArea(boardPostMove, boardPostMove.OpponentPlayer);
// if we are walled off, switch to end game
if (myArea.All(x => !oppArea.Contains(x)))
{
_isWalledOff = true;
_config.GameMode = GameMode.End;
}
else // we aren't walled off
{
// if it's time for end game, switch and max out depth
if (emptySpaces <= 28)
{
_config.DepthLimit = 30;
_config.GameMode = GameMode.End;
}
// if we think we're going to lose, try to find our best move b/c alpha-beta will pick a random one
else if (bestMoveResult.Score == int.MinValue)
{
var tasksByDepthLimit = new Dictionary<int, AsyncSearchTask>();
// simultaneously search at smaller depths to get our best move that isn't -infinity
for (var newDepthLimit = _config.DepthLimit - 1; newDepthLimit > _config.DepthLimit/2; newDepthLimit--)
{
var newConfig = new SearchConfig(_config) { DepthLimit = newDepthLimit };
// new task with timeout set at our remaining time
var task = new AsyncSearchTask(_config.MoveTimeout.Subtract(elapsed));
task.BestMoveTask = Task.Factory.StartNew(() =>
{
task.Timer.StartTimer();
var result = MoveGetter().BestMove(board, newConfig, task.Timer, task.CancelSource.Token);
task.Timer.StopTimer();
return result;
}, task.CancelSource.Token);
tasksByDepthLimit[newDepthLimit] = task;
}
foreach (var kvp in tasksByDepthLimit.OrderBy(x => x.Key))
{
var newBestMove = kvp.Value.BestMoveTask.Result;
// if we think we're going to lose or we timed out, cancel all deeper tasks because they will also think we're going to lose
if (newBestMove.Score == int.MinValue || kvp.Value.Timer.Timeout())
{
var kvpClosure = kvp;
foreach (var task in tasksByDepthLimit.Where(x => x.Key > kvpClosure.Key).Select(x => x.Value).Where(x => !x.BestMoveTask.IsCompleted))
{
task.CancelSource.Cancel();
}
break;
}
// if we found a better move, use it
if (newBestMove.Score > bestMoveResult.Score)
{
bestMoveResult = newBestMove;
}
}
}
}
}
return bestMoveResult.Move;
}
public void Initialize(SearchConfig config)
{
_config = config;
// tell move timer about timeout
MoveTimer.I.SetTimeout(config.MoveTimeout);
}