public TurnResult PlayTurn(Turn turn)
{
TurnResult turnResult = GameState.PlayTurn(turn);
PlayedTurns.Add(Tuple.Create(turn, turnResult));
Board.LastTurn = turn;
return(turnResult);
}
public void Progress()
{
TurnPlay?.Invoke(this, new GameEventArgs(Game, null));
int inTurnPlayerIndex = Game.GameState.InTurnPlayerIndex;
Turn turn = GameClients[inTurnPlayerIndex].GetTurn(Game);
TurnResult turnResult = Game.PlayTurn(turn);
TurnPlayed?.Invoke(this, new TurnEventArgs(Game, turn, turnResult));
}
/// <summary>
/// This method runs the ABS algorithm parallel, in the following way:
/// Only parallelize the calculation of the score of the depth=1 nodes, then take the max of those.
/// To do the calculation of the depth=1 node correctly, we need to pass on the Invert=true property and set MaxMoves one lower.
/// Also, we need to sort on evaluation score as usual.
/// Finally, in order for the pruning to work well, we have to pass on the updated Min (alpha) as much as possible.
/// Here, we have a trade-off: on the one hand we want to pass on the updated Min value immediately to the next node, but then we can't parallelize anything.
/// On the other hand, if we parallelize with 8 cores and start calculating 8 nodes immediately with Min = -inf, then those calculations might all be slow, and the parallelizing overhead results in time lost instead of time won.
/// After some trial, parallelizing 4 seems to have the best results.
/// </summary>
/// <param name="originalGame"></param>
/// <returns></returns>
private Turn GetTurnParallel(Game originalGame)
{
try {
GameClientStatsCollector?.StartGetTurn(originalGame);
List <Tuple <Turn, Game, double> > games = new List <Tuple <Turn, Game, double> >();
foreach (Turn turn in originalGame.GetValidTurns())
{
TurnResult turnResult = null;
try {
turnResult = originalGame.GameState.PlayTurn(turn);
var game = originalGame.Clone();
double score = Evaluator.Evaluate(game, 1 - game.GameState.InTurnPlayerIndex);
// @@@ if the turn is directly winning, we are still going to try to explore the subtree and that leads to problems.
games.Add(Tuple.Create(turn, game, score));
} finally {
// roll back
originalGame.GameState.UndoTurn(turn, turnResult);
}
}
ConcurrentBag <Tuple <Turn, double> > bag = new ConcurrentBag <Tuple <Turn, double> >();
object dummyLock = new object();
double min = AlphaBetaSearch.GameResultLosing;
var orderedGames = games.OrderByDescending(t => t.Item3).ToList();
Parallel.ForEach(orderedGames,
new ParallelOptions()
{
MaxDegreeOfParallelism = Math.Min(4, Environment.ProcessorCount)
},
tup => {
Turn turn = tup.Item1;
var game = tup.Item2;
AlphaBetaSearch abs = new AlphaBetaSearch(game, MaxMoves - 1, Evaluator, false, DoPrune, CollectStats, DoLog, invert: true, startingMin: min);
var gameResults = abs.GetGameResult();
var gameResult = gameResults.Item1;
lock (dummyLock) {
min = Math.Max(min, gameResult);
}
bag.Add(Tuple.Create(turn, gameResult));
});
var best = bag.OrderByDescending(tup => tup.Item2).First();
GameResult = best.Item2;
return(best.Item1);
} finally {
GameClientStatsCollector?.EndGetTurn();
}
}
public void UndoTurn(Turn turn, TurnResult turnResult, bool doChecks = true)
{
MiniMax.UndoTurnCount++;
AlphaBetaSearch.UndoTurnCount++;
InTurnPlayerIndex = 1 - InTurnPlayerIndex;
WinningPlayerIndex = null;
Vector movedPosition = turn.OriginalPosition.Add(turn.Move);
Piece piece = Board[movedPosition.X, movedPosition.Y];
if (turnResult.CapturedPieceType != null)
{
Piece capturedPiece = CapturedPieces.Pop();
if (doChecks)
{
if (!capturedPiece.IsCaptured)
{
throw new Exception("Huh");
}
if (capturedPiece.PlayerIndex != 1 - InTurnPlayerIndex)
{
throw new Exception("huh");
}
if (capturedPiece.PieceType != turnResult.CapturedPieceType)
{
throw new ArgumentException("Bad TurnResult.CapturedPieceType");
}
if (!capturedPiece.Position.Equals(movedPosition))
{
throw new ArgumentException("Bad CapturedPiece Position mismatch");
}
}
capturedPiece.IsCaptured = false;
Board[movedPosition.X, movedPosition.Y] = capturedPiece;
}
else
{
Board[movedPosition.X, movedPosition.Y] = null;
}
piece.Position = turn.OriginalPosition;
Board[turn.OriginalPosition.X, turn.OriginalPosition.Y] = piece;
Card tmp = GameCards[MiddleCardIndex];
GameCards[MiddleCardIndex] = GameCards[PlayerCardIndices[InTurnPlayerIndex][turn.CardIndex]];
GameCards[PlayerCardIndices[InTurnPlayerIndex][turn.CardIndex]] = tmp;
}
/// <summary>
/// Returns all neighbouring states and whether or not the move to the neighbouring state is winning or not.
/// Changes Game.GameState during loop.
/// </summary>
private IEnumerable <Tuple <Turn, bool> > GetNeighbours()
{
GetNeighboursCount++;
foreach (Turn turn in Game.GetValidTurns())
{
TurnResult turnResult = null;
try {
turnResult = Game.GameState.PlayTurn(turn, DoChecks);
if (turnResult.GameIsFinished)
{
yield return(Tuple.Create(turn, true));
}
else
{
yield return(Tuple.Create(turn, false));
}
} finally {
// roll back
Game.GameState.UndoTurn(turn, turnResult, DoChecks);
}
}
}
/// <summary>
/// Returns all neighbouring states and whether or not the move to the neighbouring state is winning or not and the neighbouring gameStateId.
/// Changes Game.GameState during loop.
/// Return neighbours in order of score of evaluation function if DoPrune is true.
/// </summary>
private IEnumerable <Tuple <Turn, bool, long?> > GetNeighbours(bool isMaxNode, int movesDone)
{
GetNeighboursCount++;
if (movesDone == MaxMoves - 1 || !DoPrune)
{
// we don't want to calculate the evaluation score of all leave nodes (to sort on them)
// because that's slower than traversing them unsorted and then (due to ABS pruning) NOT calculating the evaluation score of some of the leaves at all.
// so, getting neighbours for the almost-leave-nodes is different than for the other nodes.
foreach (Turn turn in Game.GetValidTurns())
{
TurnResult turnResult = null;
try {
turnResult = Game.GameState.PlayTurn(turn, DoChecks);
if (turnResult.GameIsFinished)
{
yield return(Tuple.Create(turn, true, (long?)null));
}
else
{
yield return(Tuple.Create(turn, false, (long?)null));
}
} finally {
// roll back
Game.GameState.UndoTurn(turn, turnResult, DoChecks);
}
}
}
else
{
List <Tuple <Turn, double, long?> > turnsWithScore = new List <Tuple <Turn, double, long?> >();
foreach (Turn turn in Game.GetValidTurns())
{
TurnResult turnResult = null;
try {
turnResult = Game.GameState.PlayTurn(turn, DoChecks);
long? gameStateId = GetUniqueIdentifier(Game.GameState); // don't calculate gameStateId again in the ABS min/max loop, so pass it on.
double score = GetEvaluationScore(gameStateId.Value);
turnsWithScore.Add(Tuple.Create(turn, score, gameStateId));
} finally {
// roll back
Game.GameState.UndoTurn(turn, turnResult, DoChecks);
}
}
if (isMaxNode)
{
turnsWithScore.Sort((tup1, tup2) => - 1 * tup1.Item2.CompareTo(tup2.Item2)); // descending by score for max nodes.
}
else
{
turnsWithScore.Sort((tup1, tup2) => 1 * tup1.Item2.CompareTo(tup2.Item2)); // ascending by score for min nodes.
}
foreach (var tup in turnsWithScore)
{
Turn turn = tup.Item1;
TurnResult turnResult = null;
long? gameStateId = tup.Item3;
try {
turnResult = Game.GameState.PlayTurn(turn, DoChecks);
if (turnResult.GameIsFinished)
{
yield return(Tuple.Create(turn, true, gameStateId));
}
else
{
yield return(Tuple.Create(turn, false, gameStateId));
}
} finally {
// roll back
Game.GameState.UndoTurn(turn, turnResult, DoChecks);
}
}
}
}
public TurnEventArgs(Game game, Turn turn, TurnResult turnResult)
{
Game = game;
Turn = turn;
TurnResult = turnResult;
}