使用したいプログラミング言語は何ですか?
C#でビットボードを実装するには、System.UInt64を使用します。これは、チェス盤の各正方形に1つずつ、64ビットを保持できます。この値タイプは、多くの高速ビット演算に適しています。
これは良いビットボードチュートリアルです。
ここに私自身のC#チェスエンジンからのいくつかの例があります。コードからわかるように、ビットボードを使用して頭を一周するのには時間がかかる場合がありますが、通常、特に位置評価の場合は非常に高速です。
例1-ビットボードの定義:
internal UInt64 WhiteKing;
internal UInt64 WhiteQueens;
internal UInt64 WhiteRooks;
internal UInt64 WhiteBishops;
internal UInt64 WhiteKnights;
internal UInt64 WhitePawns;
internal UInt64 WhitePieces;
例2-ビットボードの初期化:
// Initialise piece bitboards using square contents.
private void InitPieceBitboards()
{
this.WhiteKing = 0;
this.WhiteQueens = 0;
this.WhiteRooks = 0;
this.WhiteBishops = 0;
this.WhiteKnights = 0;
this.WhitePawns = 0;
for (Int16 i = 0; i < 64; i++)
{
if (this.Squares[i] == Constants.WHITE_KING)
{
this.WhiteKing = this.WhiteKing | Constants.BITSET[i];
}
if (this.Squares[i] == Constants.WHITE_QUEEN)
{
this.WhiteQueens = this.WhiteQueens | Constants.BITSET[i];
}
if (this.Squares[i] == Constants.WHITE_ROOK)
{
this.WhiteRooks = this.WhiteRooks | Constants.BITSET[i];
}
if (this.Squares[i] == Constants.WHITE_BISHOP)
{
this.WhiteBishops = this.WhiteBishops | Constants.BITSET[i];
}
if (this.Squares[i] == Constants.WHITE_KNIGHT)
{
this.WhiteKnights = this.WhiteKnights | Constants.BITSET[i];
}
if (this.Squares[i] == Constants.WHITE_PAWN)
{
this.WhitePawns = this.WhitePawns | Constants.BITSET[i];
}
this.WhitePieces = this.WhiteKing | this.WhiteQueens |
this.WhiteRooks | this.WhiteBishops |
this.WhiteKnights | this.WhitePawns;
this.BlackPieces = this.BlackKing | this.BlackQueens |
this.BlackRooks | this.BlackBishops |
this.BlackKnights | this.BlackPawns;
this.SquaresOccupied = this.WhitePieces | this.BlackPieces;
}
}
例3-世代の移動:
// We can't capture one of our own pieces.
eligibleSquares = ~this.WhitePieces;
// Generate moves for white knights.
remainingKnights = this.WhiteKnights;
// Generate the moves for each knight...
while (remainingKnights != 0)
{
squareFrom = BitOps.BitScanForward(remainingKnights);
generatedMoves = Constants.ATTACKS_KNIGHT[squareFrom] & eligibleSquares;
while (generatedMoves != 0)
{
squareTo = BitOps.BitScanForward(generatedMoves);
moveList.Add(new Move(squareFrom, squareTo, Constants.WHITE_KNIGHT,
this.Squares[squareTo], Constants.EMPTY));
generatedMoves ^= Constants.BITSET[squareTo];
}
// Finished with this knight - move on to the next one.
remainingKnights ^= Constants.BITSET[squareFrom];
}
例4-材料スコアを計算します。
// Material score from scratch, in centipawns from White's perspective.
internal static Int32 ScoreMaterial(Board position)
{
return BitOps.BitCountWegner(position.WhitePawns) * Constants.VALUE_PAWN +
BitOps.BitCountWegner(position.WhiteKnights) * Constants.VALUE_KNIGHT +
BitOps.BitCountWegner(position.WhiteBishops) * Constants.VALUE_BISHOP +
BitOps.BitCountWegner(position.WhiteRooks) * Constants.VALUE_ROOK +
BitOps.BitCountWegner(position.WhiteQueens) * Constants.VALUE_QUEEN -
BitOps.BitCountWegner(position.BlackPawns) * Constants.VALUE_PAWN -
BitOps.BitCountWegner(position.BlackKnights) * Constants.VALUE_KNIGHT -
BitOps.BitCountWegner(position.BlackBishops) * Constants.VALUE_BISHOP -
BitOps.BitCountWegner(position.BlackRooks) * Constants.VALUE_ROOK -
BitOps.BitCountWegner(position.BlackQueens) * Constants.VALUE_QUEEN;
}
例5-ピースの移動度の計算:
// Calculate mobility score for white knights.
remainingPieces = position.WhiteKnights;
while (remainingPieces != 0)
{
squareFrom = BitOps.BitScanForward(remainingPieces);
mobilityKnight += BitOps.BitCountWegner(Constants.ATTACKS_KNIGHT[squareFrom]
& unoccupiedSquares);
remainingPieces ^= Constants.BITSET[squareFrom];
}