public Engine(string[] args)
{
inOut.WriteLine(Misc.engine_info(), MutexAction.ATOMIC);
Uci.init(Options);
BitBoard.init();
Position.init();
Bitbases.init_kpk();
Search.init();
Pawns.init();
Eval.init();
Threads.init();
TT.resize((ulong)Options["Hash"].getInt());
Uci.loop(args);
Threads.exit();
}
public Result classify(KPKPosition[] db, Color Us)
{
// White to Move: If one move leads to a position classified as WIN, the result
// of the current position is WIN. If all moves lead to positions classified
// as DRAW, the current position is classified as DRAW, otherwise the current
// position is classified as UNKNOWN.
//
// Black to Move: If one move leads to a position classified as DRAW, the result
// of the current position is DRAW. If all moves lead to positions classified
// as WIN, the position is classified as WIN, otherwise the current position is
// classified as UNKNOWN.
Color Them = (Us == ColorS.WHITE ? ColorS.BLACK : ColorS.WHITE);
Result r = Result.INVALID;
Bitboard b = BitBoard.StepAttacksBB[PieceTypeS.KING][Us == ColorS.WHITE ? wksq : bksq];
while (b != 0)
{
r |= (Us == ColorS.WHITE) ? db[Bitbases.index(Them, bksq, BitBoard.pop_lsb(ref b), psq)].result
: db[Bitbases.index(Them, BitBoard.pop_lsb(ref b), wksq, psq)].result;
}
if (Us == ColorS.WHITE && Types.rank_of(psq) < RankS.RANK_7)
{
Square s = (psq + SquareS.DELTA_N);
r |= db[Bitbases.index(ColorS.BLACK, bksq, wksq, s)].result; // Single push
if (Types.rank_of(psq) == RankS.RANK_2 && s != wksq && s != bksq)
{
r |= db[Bitbases.index(ColorS.BLACK, bksq, wksq, s + SquareS.DELTA_N)].result; // Double push
}
}
if (Us == ColorS.WHITE)
{
return(result = (r & Result.WIN) != 0 ? Result.WIN : (r & Result.UNKNOWN) != 0 ? Result.UNKNOWN : Result.DRAW);
}
else
{
return(result = (r & Result.DRAW) != 0 ? Result.DRAW : (r & Result.UNKNOWN) != 0 ? Result.UNKNOWN : Result.WIN);
}
}
/// KP vs K. This endgame is evaluated with the help of a bitbase.
public Value KPK(Position pos)
{
Debug.Assert(verify_material(pos, strongSide, ValueS.VALUE_ZERO, 1));
Debug.Assert(verify_material(pos, weakSide, ValueS.VALUE_ZERO, 0));
// Assume strongSide is white and the pawn is on files A-D
Square wksq = normalize(pos, strongSide, pos.king_square(strongSide));
Square bksq = normalize(pos, strongSide, pos.king_square(weakSide));
Square psq = normalize(pos, strongSide, pos.list(strongSide, PieceTypeS.PAWN)[0]);
Color us = strongSide == pos.side_to_move() ? ColorS.WHITE : ColorS.BLACK;
if (!Bitbases.probe_kpk(wksq, psq, bksq, us))
{
return(ValueS.VALUE_DRAW);
}
Value result = ValueS.VALUE_KNOWN_WIN + ValueS.PawnValueEg + Types.rank_of(psq);
return(strongSide == pos.side_to_move() ? result : -result);
}
/// KP vs KP. This is done by removing the weakest side's pawn and probing the
/// KP vs K bitbase: If the weakest side has a draw without the pawn, it probably
/// has at least a draw with the pawn as well. The exception is when the stronger
/// side's pawn is far advanced and not on a rook file; in this case it is often
/// possible to win (e.g. 8/4k3/3p4/3P4/6K1/8/8/8 w - - 0 1).
public ScaleFactor KPKP(Position pos)
{
Debug.Assert(verify_material(pos, strongSide, ValueS.VALUE_ZERO, 1));
Debug.Assert(verify_material(pos, weakSide, ValueS.VALUE_ZERO, 1));
// Assume strongSide is white and the pawn is on files A-D
Square wksq = normalize(pos, strongSide, pos.king_square(strongSide));
Square bksq = normalize(pos, strongSide, pos.king_square(weakSide));
Square psq = normalize(pos, strongSide, pos.list(strongSide, PieceTypeS.PAWN)[0]);
Color us = strongSide == pos.side_to_move() ? ColorS.WHITE : ColorS.BLACK;
// If the pawn has advanced to the fifth rank or further, and is not a
// rook pawn, it's too dangerous to assume that it's at least a draw.
if (Types.rank_of(psq) >= RankS.RANK_5 && Types.file_of(psq) != FileS.FILE_A)
{
return(ScaleFactorS.SCALE_FACTOR_NONE);
}
// Probe the KPK bitbase with the weakest side's pawn removed. If it's a draw,
// it's probably at least a draw even with the pawn.
return(Bitbases.probe_kpk(wksq, psq, bksq, us) ? ScaleFactorS.SCALE_FACTOR_NONE : ScaleFactorS.SCALE_FACTOR_DRAW);
}
