private double HeuristicEval(BoardStates player, OthelloGame game)
{
//Based of features of the board that humans have identified.
//Hints of evaluation from any source I could find
//idealy these could me optimized using a genetic algorithm,
//but that is a different project
const int searchableDepthOverride = 2; //override min-max in favor of complete evaluation
const int endGame = 20; //<20 moves is endgame
const int midGame = 40; // 20 moves in is midgame
double value = 0;
int empty = game.GetPieceCount(BoardStates.empty);
if (game.GameComplete)
{
return(CompleteEval(player, game));
}
else if (empty < searchableDepthOverride)
{
return(MinimaxAlphaBeta(game, searchableDepthOverride, int.MinValue, int.MaxValue, player));
}
value += coinDiffWeight * Math.Pow((game.GetPieceCount(player) - game.GetPieceCount(~player) + empty - coinDiffOffset), coinDiffPower);
value += cornerDiffWeight * Math.Pow((game.GetCornerCount(player) - game.GetCornerCount(~player) + empty - cornerDiffOffset), cornerDiffPower);
value += nearCornerDiffWeight * Math.Pow((game.GetAdjCornerCount(player) - game.GetAdjCornerCount(~player) + empty - nearCornerDiffOffset), nearCornerDiffPower);
value += avalibleMoveDiffWeight * Math.Pow((game.GetPossiblePlayList(player).Count() - game.GetPossiblePlayList(~player).Count() + empty - avalibleMoveDiffOffset), avalibleMoveDiffPower);
value += nonTurnableCoinDiffWeight * Math.Pow((game.GetSafePeiceCountEstimation(player) - game.GetSafePeiceCountEstimation(~player) + empty - nonTurnableCoinDiffOffset), nonTurnableCoinDiffPower);
value += ControlledCornerDiffWeight * Math.Pow((game.GetControlledCorners(player) - game.GetControlledCorners(~player) + empty - ControlledCornerDiffOffset), ControlledCornerDiffPower);
return(value);
}
public static BoardStates GetCurrentLeader(OthelloGame game)
{
BoardStates leader = BoardStates.empty;
leader = game.GetPieceCount(BoardStates.white) > game.GetPieceCount(BoardStates.black)
? BoardStates.white : BoardStates.black;
return(leader);
}
public static void TestMinMax(OthelloGame _myGame, int minimaxDepth = 3)
{
const int testCount = 100;
object wonGamesLock = new object();
int wonGames = 0;
object tieGamesLock = new object();
int tieGames = 0;
var stopwatch = Stopwatch.StartNew();
//Parallel.For(0, testCount, new ParallelOptions { MaxDegreeOfParallelism = Environment.ProcessorCount },index =>
//{
for (int index = 0; index < testCount; index++)
{//non-parallel for loop to debug
BoardStates player = (index % 2 == 0) ? BoardStates.black : BoardStates.white;
OthelloGame testGame = new OthelloGame();
MinMaxAgent othelloAgent = new MinMaxAgent(2);
RandomAgent randAgent = new RandomAgent();
while (!testGame.GameComplete)
{
if (testGame.WhosTurn == player)
{
testGame.MakeMove(othelloAgent.MakeMove(testGame, player));
}
else
{
testGame.MakeMove(randAgent.MakeMove(testGame, ~player));
}
}
if (testGame.GameComplete)//just gotta check
{
if (testGame.FinalWinner == player)
{
lock (wonGamesLock) { wonGames++; }
}
else if (testGame.FinalWinner == BoardStates.empty)
{
lock (tieGamesLock) { tieGames++; }
}
Console.WriteLine("Finished Game " + index + ", " + testGame.FinalWinner.ToString()
+ " won " + testGame.GetPieceCount(testGame.FinalWinner) + " to "
+ testGame.GetPieceCount(OthelloGame.OpposingPlayer(testGame.FinalWinner)));;
}
else
{
throw new Exception("MiniMax Testing didn't complete a game");
}
}
//});
stopwatch.Stop();
Console.WriteLine("Won " + wonGames + " / " + testCount + " games, " + ((double)wonGames / testCount) * 100 + " %");
Console.WriteLine("Tied " + tieGames + " / " + testCount + " games, " + ((double)tieGames / testCount) * 100 + " %");
Console.WriteLine("Lost " + (testCount - wonGames - tieGames) + " / " + testCount + " games, " + ((double)(testCount - wonGames - tieGames) / testCount) * 100 + " %");
Console.WriteLine("Elapsed time for games : {0}", stopwatch.Elapsed);
}
private static byte[] OpeningMove(BoardStates player, OthelloGame game)
{//avoid computation for first move - only one symmetric option
//randomly select perpendicular or diagonal for second move - parallel
//has been shown to be much worse
//SPECIFIC TO 8x8 BOARDS
byte[][] firstMoves = new byte[4][] {
new byte[] { 2, 3 },
new byte[] { 3, 2 },
new byte[] { 4, 5 },
new byte[] { 5, 4 }
};
if (game.GetPieceCount(BoardStates.empty) == 60)
{
Random rndGen = new Random();
int rand = (int)Math.Ceiling(rndGen.NextDouble() * 4);
switch (rand)
{
case 1:
return(firstMoves[0]);
case 2:
return(firstMoves[1]);
case 3:
return(firstMoves[2]);
case 4:
return(firstMoves[3]);
default:
throw new Exception("OpeningMove has faulted with random number generation");
}
}
if (game.GetPieceCount(BoardStates.empty) == 59)
{
List <byte[]> moves = game.GetPossiblePlayList();
Random rndGen = new Random();
byte rand = (byte)Math.Ceiling(rndGen.NextDouble() * 2);
switch (rand)
{
case 1: //diagonal
return(moves[0]);
case 2: //perpendicular
return(moves[0]);
default:
throw new Exception("Opening move has faulted with random number generation");
}
}
return(new byte[] { byte.MaxValue, byte.MaxValue });
}
private byte[] PredictBestMove(int depth, OthelloGame game, BoardStates player)
{
byte[] bestMove = new byte[] { byte.MaxValue, byte.MaxValue };
List <byte[]> moves = game.GetPossiblePlayList();
double bestScore = int.MinValue + 1;
if (game.GetPieceCount(BoardStates.empty) > 58)//first two moves, don't compute
{
return(OpeningMove(player, game));
}
else if (moves.Count == 1) //don't compute if there is only 1 move
{
return(moves[0]);
}
foreach (byte[] move in moves)
{
OthelloGame testGame = game.DeepCopy();
testGame.MakeMove(move);
double thisScore = MinimaxAlphaBeta(testGame, depth - 1, double.MinValue, double.MaxValue, player);
if (thisScore > bestScore)
{
bestScore = thisScore;
bestMove = move;
}
}
return(bestMove);
}
