Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#include <cassert>
#include "bitboard.h"
-#include "bitcount.h"
#include "endgame.h"
#include "movegen.h"
70, 50, 30, 20, 20, 30, 50, 70,
80, 60, 40, 30, 30, 40, 60, 80,
90, 70, 60, 50, 50, 60, 70, 90,
- 100, 90, 80, 70, 70, 80, 90, 100,
+ 100, 90, 80, 70, 70, 80, 90, 100
};
// Table used to drive the king towards a corner square of the
const int PushClose[8] = { 0, 0, 100, 80, 60, 40, 20, 10 };
const int PushAway [8] = { 0, 5, 20, 40, 60, 80, 90, 100 };
+ // Pawn Rank based scaling factors used in KRPPKRP endgame
+ const int KRPPKRPScaleFactors[RANK_NB] = { 0, 9, 10, 14, 21, 44, 0, 0 };
+
#ifndef NDEBUG
bool verify_material(const Position& pos, Color c, Value npm, int pawnsCnt) {
return pos.non_pawn_material(c) == npm && pos.count<PAWN>(c) == pawnsCnt;
return sq;
}
- // Get the material key of Position out of the given endgame key code
- // like "KBPKN". The trick here is to first forge an ad-hoc FEN string
- // and then let a Position object do the work for us.
- Key key(const string& code, Color c) {
-
- assert(code.length() > 0 && code.length() < 8);
- assert(code[0] == 'K');
-
- string sides[] = { code.substr(code.find('K', 1)), // Weak
- code.substr(0, code.find('K', 1)) }; // Strong
-
- std::transform(sides[c].begin(), sides[c].end(), sides[c].begin(), tolower);
-
- string fen = sides[0] + char(8 - sides[0].length() + '0') + "/8/8/8/8/8/8/"
- + sides[1] + char(8 - sides[1].length() + '0') + " w - - 0 10";
-
- return Position(fen, false, nullptr).material_key();
- }
-
} // namespace
}
-template<EndgameType E, typename T>
-void Endgames::add(const string& code) {
- map<T>()[key(code, WHITE)] = std::unique_ptr<EndgameBase<T>>(new Endgame<E>(WHITE));
- map<T>()[key(code, BLACK)] = std::unique_ptr<EndgameBase<T>>(new Endgame<E>(BLACK));
-}
-
-
/// Mate with KX vs K. This function is used to evaluate positions with
/// king and plenty of material vs a lone king. It simply gives the
/// attacking side a bonus for driving the defending king towards the edge
||(pos.count<BISHOP>(strongSide) && pos.count<KNIGHT>(strongSide))
||(pos.count<BISHOP>(strongSide) > 1 && opposite_colors(pos.squares<BISHOP>(strongSide)[0],
pos.squares<BISHOP>(strongSide)[1])))
- result += VALUE_KNOWN_WIN;
+ result = std::min(result + VALUE_KNOWN_WIN, VALUE_MATE_IN_MAX_PLY - 1);
return strongSide == pos.side_to_move() ? result : -result;
}
result = Value(80) - 8 * distance(wksq, psq);
else
- result = Value(200) - 8 * ( distance(wksq, psq + DELTA_S)
- - distance(bksq, psq + DELTA_S)
+ result = Value(200) - 8 * ( distance(wksq, psq + SOUTH)
+ - distance(bksq, psq + SOUTH)
- distance(psq, queeningSq));
return strongSide == pos.side_to_move() ? result : -result;
// If the defending king blocks the pawn and the attacking king is too far
// away, it's a draw.
if ( r <= RANK_5
- && bksq == wpsq + DELTA_N
+ && bksq == wpsq + NORTH
&& distance(wksq, wpsq) - tempo >= 2
&& distance(wksq, brsq) - tempo >= 2)
return SCALE_FACTOR_DRAW;
&& file_of(wrsq) == f
&& wrsq < wpsq
&& (distance(wksq, queeningSq) < distance(bksq, queeningSq) - 2 + tempo)
- && (distance(wksq, wpsq + DELTA_N) < distance(bksq, wpsq + DELTA_N) - 2 + tempo)
+ && (distance(wksq, wpsq + NORTH) < distance(bksq, wpsq + NORTH) - 2 + tempo)
&& ( distance(bksq, wrsq) + tempo >= 3
|| ( distance(wksq, queeningSq) < distance(bksq, wrsq) + tempo
- && (distance(wksq, wpsq + DELTA_N) < distance(bksq, wrsq) + tempo))))
+ && (distance(wksq, wpsq + NORTH) < distance(bksq, wrsq) + tempo))))
return ScaleFactor( SCALE_FACTOR_MAX
- 8 * distance(wpsq, queeningSq)
- 2 * distance(wksq, queeningSq));
&& distance<File>(bksq, wpsq2) <= 1
&& relative_rank(strongSide, bksq) > r)
{
- switch (r) {
- case RANK_2: return ScaleFactor(9);
- case RANK_3: return ScaleFactor(10);
- case RANK_4: return ScaleFactor(14);
- case RANK_5: return ScaleFactor(21);
- case RANK_6: return ScaleFactor(44);
- default: assert(false);
- }
+ assert(r > RANK_1 && r < RANK_7);
+ return ScaleFactor(KRPPKRPScaleFactors[r]);
}
return SCALE_FACTOR_NONE;
}
if (relative_rank(strongSide, pawnSq) <= RANK_5)
return SCALE_FACTOR_DRAW;
- else
- {
- Bitboard path = forward_bb(strongSide, pawnSq);
- if (path & pos.pieces(weakSide, KING))
- return SCALE_FACTOR_DRAW;
+ Bitboard path = forward_bb(strongSide, pawnSq);
- if ( (pos.attacks_from<BISHOP>(weakBishopSq) & path)
- && distance(weakBishopSq, pawnSq) >= 3)
- return SCALE_FACTOR_DRAW;
- }
+ if (path & pos.pieces(weakSide, KING))
+ return SCALE_FACTOR_DRAW;
+
+ if ( (pos.attacks_from<BISHOP>(weakBishopSq) & path)
+ && distance(weakBishopSq, pawnSq) >= 3)
+ return SCALE_FACTOR_DRAW;
}
return SCALE_FACTOR_NONE;
}
projects / stockfish / blobdiff