static Zero()
{
// Initialize piece values. The king's value is only used for static
// exchange evaluation.
PieceValue[Piece.King] = 3000;
PieceValue[Piece.Queen] = 1025;
PieceValue[Piece.Rook] = 575;
PieceValue[Piece.Bishop] = 370;
PieceValue[Piece.Knight] = 350;
PieceValue[Piece.Pawn] = 100;
for (Int32 piece = Piece.Min; piece <= Piece.Max; piece += 2)
{
PieceValue[Colour.Black | piece] = PieceValue[piece];
}
PieceValue[Piece.Empty] = 0;
PhaseCoefficient += PieceValue[Piece.Queen];
PhaseCoefficient += 2 * PieceValue[Piece.Rook];
PhaseCoefficient += 2 * PieceValue[Piece.Bishop];
PhaseCoefficient += 2 * PieceValue[Piece.Knight];
PhaseCoefficient += 8 * PieceValue[Piece.Pawn];
PhaseCoefficient = 1 / PhaseCoefficient;
for (Int32 square = 0; square < 64; square++)
{
// Initialize piece square tables.
Int32 reflected = Position.File(square) + (7 - Position.Rank(square)) * 8;
KingOpeningPositionValue[Colour.Black][square] = KingOpeningPositionValue[Colour.White][reflected];
KingEndgamePositionValue[Colour.Black][square] = KingEndgamePositionValue[Colour.White][reflected];
QueenOpeningPositionValue[Colour.Black][square] = QueenOpeningPositionValue[Colour.White][reflected];
RookPositionValue[Colour.Black][square] = RookPositionValue[Colour.White][reflected];
BishopPositionValue[Colour.Black][square] = BishopPositionValue[Colour.White][reflected];
KnightOpeningPositionValue[Colour.Black][square] = KnightOpeningPositionValue[Colour.White][reflected];
PawnPositionValue[Colour.Black][square] = PawnPositionValue[Colour.White][reflected];
PassedPawnEndgamePositionValue[Colour.Black][square] = PassedPawnEndgamePositionValue[Colour.White][reflected];
// Initialize pawn shield bitboard table.
PawnShieldBitboard[square] = Bit.File[square];
if (Position.File(square) > 0)
{
PawnShieldBitboard[square] |= Bit.File[square - 1];
}
if (Position.File(square) < 7)
{
PawnShieldBitboard[square] |= Bit.File[square + 1];
}
PawnShieldBitboard[square] &= Bit.FloodFill(square, 2);
// Initialize short adjacent files bitboard table.
if (Position.File(square) > 0)
{
ShortAdjacentFilesBitboard[square] |= Bit.File[square - 1] & Bit.FloodFill(square - 1, 3);
}
if (Position.File(square) < 7)
{
ShortAdjacentFilesBitboard[square] |= Bit.File[square + 1] & Bit.FloodFill(square + 1, 3);
}
// Initialize pawn blockade bitboard table.
PawnBlockadeBitboard[Colour.White][square] = Bit.RayN[square];
if (Position.File(square) > 0)
{
PawnBlockadeBitboard[Colour.White][square] |= Bit.RayN[square - 1];
}
if (Position.File(square) < 7)
{
PawnBlockadeBitboard[Colour.White][square] |= Bit.RayN[square + 1];
}
PawnBlockadeBitboard[Colour.Black][square] = Bit.RayS[square];
if (Position.File(square) > 0)
{
PawnBlockadeBitboard[Colour.Black][square] |= Bit.RayS[square - 1];
}
if (Position.File(square) < 7)
{
PawnBlockadeBitboard[Colour.Black][square] |= Bit.RayS[square + 1];
}
// Initialize short forward file bitboard table.
ShortForwardFileBitboard[Colour.White][square] = Bit.RayN[square] & Bit.FloodFill(square, 3);
ShortForwardFileBitboard[Colour.Black][square] = Bit.RayS[square] & Bit.FloodFill(square, 3);
// Initialize rectilinear distance table.
RectilinearDistance[square] = new Int32[64];
for (Int32 to = 0; to < 64; to++)
{
RectilinearDistance[square][to] = Math.Abs(Position.File(square) - Position.File(to)) + Math.Abs(Position.Rank(square) - Position.Rank(to));
}
// Initialize chebyshev distance table.
ChebyshevDistance[square] = new Int32[64];
for (Int32 to = 0; to < 64; to++)
{
ChebyshevDistance[square][to] = Math.Max(Math.Abs(Position.File(square) - Position.File(to)), Math.Abs(Position.Rank(square) - Position.Rank(to)));
}
// Initialize knight move distance table.
KnightMoveDistance[square] = new Int32[64];
for (Int32 i = 0; i < KnightMoveDistance[square].Length; i++)
{
KnightMoveDistance[square][i] = 6;
}
for (Int32 moves = 1; moves <= 5; moves++)
{
UInt64 moveBitboard = Attack.KnightFill(square, moves);
for (Int32 to = 0; to < 64; to++)
{
if ((moveBitboard & (1UL << to)) != 0 && moves < KnightMoveDistance[square][to])
{
KnightMoveDistance[square][to] = moves;
}
}
}
}
}