X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=src%2Fendgame.cpp;h=7f26dbf5053c856c9bcc7aab448a9f62fae77290;hb=bdbbc4e06bbc1d8437cfdc31cc35006f1ee5f0c9;hp=ee8b9179c2d79ecfab93a197b329cd353041604d;hpb=d4f14a8e83de85073483adacb22b760287d338ac;p=stockfish
diff --git a/src/endgame.cpp b/src/endgame.cpp
index ee8b9179..7f26dbf5 100644
--- a/src/endgame.cpp
+++ b/src/endgame.cpp
@@ -1,17 +1,18 @@
/*
- Glaurung, a UCI chess playing engine.
- Copyright (C) 2004-2008 Tord Romstad
+ Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+ Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
+ Copyright (C) 2008 Marco Costalba
- Glaurung is free software: you can redistribute it and/or modify
+ Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
-
- Glaurung is distributed in the hope that it will be useful,
+
+ Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
-
+
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
@@ -61,6 +62,13 @@ KRKNEvaluationFunction EvaluateKNKR = KRKNEvaluationFunction(BLACK);
KQKREvaluationFunction EvaluateKQKR = KQKREvaluationFunction(WHITE);
KQKREvaluationFunction EvaluateKRKQ = KQKREvaluationFunction(BLACK);
+// KBB vs KN:
+KBBKNEvaluationFunction EvaluateKBBKN = KBBKNEvaluationFunction(WHITE);
+KBBKNEvaluationFunction EvaluateKNKBB = KBBKNEvaluationFunction(BLACK);
+
+// K and two minors vs K and one or two minors:
+KmmKmEvaluationFunction EvaluateKmmKm = KmmKmEvaluationFunction(WHITE);
+
/// Scaling functions
@@ -145,7 +153,7 @@ namespace {
const int KRKNKingKnightDistancePenalty[8] = { 0, 0, 4, 10, 20, 32, 48, 70 };
// Various inline functions for accessing the above arrays:
-
+
inline Value mate_table(Square s) {
return Value(MateTable[s]);
}
@@ -166,7 +174,7 @@ namespace {
int probe_kpk(Square wksq, Square wpsq, Square bksq, Color stm);
}
-
+
////
//// Functions
@@ -186,6 +194,8 @@ KRKPEvaluationFunction::KRKPEvaluationFunction(Color c) : EndgameEvaluationFunct
KRKBEvaluationFunction::KRKBEvaluationFunction(Color c) : EndgameEvaluationFunction(c) { }
KRKNEvaluationFunction::KRKNEvaluationFunction(Color c) : EndgameEvaluationFunction(c) { }
KQKREvaluationFunction::KQKREvaluationFunction(Color c) : EndgameEvaluationFunction(c) { }
+KBBKNEvaluationFunction::KBBKNEvaluationFunction(Color c) : EndgameEvaluationFunction(c) { }
+KmmKmEvaluationFunction::KmmKmEvaluationFunction(Color c) : EndgameEvaluationFunction(c) { }
ScalingFunction::ScalingFunction(Color c) {
@@ -212,19 +222,19 @@ KPKPScalingFunction::KPKPScalingFunction(Color c) : ScalingFunction(c) { }
Value KXKEvaluationFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(weakerSide) == Value(0));
- assert(pos.pawn_count(weakerSide) == Value(0));
+ assert(pos.piece_count(weakerSide, PAWN) == Value(0));
Square winnerKSq = pos.king_square(strongerSide);
Square loserKSq = pos.king_square(weakerSide);
Value result =
pos.non_pawn_material(strongerSide) +
- pos.pawn_count(strongerSide) * PawnValueEndgame +
+ pos.piece_count(strongerSide, PAWN) * PawnValueEndgame +
mate_table(loserKSq) +
distance_bonus(square_distance(winnerKSq, loserKSq));
- if(pos.queen_count(strongerSide) > 0 || pos.rook_count(strongerSide) > 0 ||
- pos.bishop_count(strongerSide) > 1)
+ if(pos.piece_count(strongerSide, QUEEN) > 0 || pos.piece_count(strongerSide, ROOK) > 0 ||
+ pos.piece_count(strongerSide, BISHOP) > 1)
// TODO: check for two equal-colored bishops!
result += VALUE_KNOWN_WIN;
@@ -234,16 +244,16 @@ Value KXKEvaluationFunction::apply(const Position &pos) {
/// Mate with KBN vs K. This is similar to KX vs K, but we have to drive the
/// defending king towards a corner square of the right color.
-
+
Value KBNKEvaluationFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(weakerSide) == Value(0));
- assert(pos.pawn_count(weakerSide) == Value(0));
+ assert(pos.piece_count(weakerSide, PAWN) == Value(0));
assert(pos.non_pawn_material(strongerSide) ==
KnightValueMidgame + BishopValueMidgame);
- assert(pos.bishop_count(strongerSide) == 1);
- assert(pos.knight_count(strongerSide) == 1);
- assert(pos.pawn_count(strongerSide) == 0);
+ assert(pos.piece_count(strongerSide, BISHOP) == 1);
+ assert(pos.piece_count(strongerSide, KNIGHT) == 1);
+ assert(pos.piece_count(strongerSide, PAWN) == 0);
Square winnerKSq = pos.king_square(strongerSide);
Square loserKSq = pos.king_square(weakerSide);
@@ -268,9 +278,9 @@ Value KPKEvaluationFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(strongerSide) == Value(0));
assert(pos.non_pawn_material(weakerSide) == Value(0));
- assert(pos.pawn_count(strongerSide) == 1);
- assert(pos.pawn_count(weakerSide) == 0);
-
+ assert(pos.piece_count(strongerSide, PAWN) == 1);
+ assert(pos.piece_count(weakerSide, PAWN) == 0);
+
Square wksq, bksq, wpsq;
Color stm;
@@ -311,9 +321,9 @@ Value KPKEvaluationFunction::apply(const Position &pos) {
Value KRKPEvaluationFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
- assert(pos.pawn_count(strongerSide) == 0);
+ assert(pos.piece_count(strongerSide, PAWN) == 0);
assert(pos.non_pawn_material(weakerSide) == 0);
- assert(pos.pawn_count(weakerSide) == 1);
+ assert(pos.piece_count(weakerSide, PAWN) == 1);
Square wksq, wrsq, bksq, bpsq;
int tempo = (pos.side_to_move() == strongerSide);
@@ -366,10 +376,10 @@ Value KRKPEvaluationFunction::apply(const Position &pos) {
Value KRKBEvaluationFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
- assert(pos.pawn_count(strongerSide) == 0);
+ assert(pos.piece_count(strongerSide, PAWN) == 0);
assert(pos.non_pawn_material(weakerSide) == BishopValueMidgame);
- assert(pos.pawn_count(weakerSide) == 0);
- assert(pos.bishop_count(weakerSide) == 1);
+ assert(pos.piece_count(weakerSide, PAWN) == 0);
+ assert(pos.piece_count(weakerSide, BISHOP) == 1);
Value result = mate_table(pos.king_square(weakerSide));
return (pos.side_to_move() == strongerSide)? result : -result;
@@ -382,10 +392,10 @@ Value KRKBEvaluationFunction::apply(const Position &pos) {
Value KRKNEvaluationFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
- assert(pos.pawn_count(strongerSide) == 0);
+ assert(pos.piece_count(strongerSide, PAWN) == 0);
assert(pos.non_pawn_material(weakerSide) == KnightValueMidgame);
- assert(pos.pawn_count(weakerSide) == 0);
- assert(pos.knight_count(weakerSide) == 1);
+ assert(pos.piece_count(weakerSide, PAWN) == 0);
+ assert(pos.piece_count(weakerSide, KNIGHT) == 1);
Square defendingKSq = pos.king_square(weakerSide);
Square nSq = pos.piece_list(weakerSide, KNIGHT, 0);
@@ -405,13 +415,13 @@ Value KRKNEvaluationFunction::apply(const Position &pos) {
Value KQKREvaluationFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(strongerSide) == QueenValueMidgame);
- assert(pos.pawn_count(strongerSide) == 0);
+ assert(pos.piece_count(strongerSide, PAWN) == 0);
assert(pos.non_pawn_material(weakerSide) == RookValueMidgame);
- assert(pos.pawn_count(weakerSide) == 0);
+ assert(pos.piece_count(weakerSide, PAWN) == 0);
Square winnerKSq = pos.king_square(strongerSide);
Square loserKSq = pos.king_square(weakerSide);
-
+
Value result = QueenValueEndgame - RookValueEndgame +
mate_table(loserKSq) + distance_bonus(square_distance(winnerKSq, loserKSq));
@@ -419,6 +429,36 @@ Value KQKREvaluationFunction::apply(const Position &pos) {
}
+Value KBBKNEvaluationFunction::apply(const Position &pos) {
+ assert(pos.piece_count(strongerSide, BISHOP) == 2);
+ assert(pos.non_pawn_material(strongerSide) == 2*BishopValueMidgame);
+ assert(pos.piece_count(weakerSide, KNIGHT) == 1);
+ assert(pos.non_pawn_material(weakerSide) == KnightValueMidgame);
+ assert(pos.pawns() == EmptyBoardBB);
+
+ Value result = BishopValueEndgame;
+ Square wksq = pos.king_square(strongerSide);
+ Square bksq = pos.king_square(weakerSide);
+ Square nsq = pos.piece_list(weakerSide, KNIGHT, 0);
+
+ // Bonus for attacking king close to defending king
+ result += distance_bonus(square_distance(wksq, bksq));
+
+ // Bonus for driving the defending king and knight apart
+ result += Value(square_distance(bksq, nsq) * 32);
+
+ // Bonus for restricting the knight's mobility
+ result += Value((8 - count_1s_max_15(pos.piece_attacks(nsq))) * 8);
+
+ return (strongerSide == pos.side_to_move())? result : -result;
+}
+
+
+Value KmmKmEvaluationFunction::apply(const Position &pos) {
+ return Value(0);
+}
+
+
/// KBPKScalingFunction scales endgames where the stronger side has king,
/// bishop and one or more pawns. It checks for draws with rook pawns and a
/// bishop of the wrong color. If such a draw is detected, ScaleFactor(0) is
@@ -427,8 +467,8 @@ Value KQKREvaluationFunction::apply(const Position &pos) {
ScaleFactor KBPKScalingFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame);
- assert(pos.bishop_count(strongerSide) == 1);
- assert(pos.pawn_count(strongerSide) >= 1);
+ assert(pos.piece_count(strongerSide, BISHOP) == 1);
+ assert(pos.piece_count(strongerSide, PAWN) >= 1);
// No assertions about the material of weakerSide, because we want draws to
// be detected even when the weaker side has some pawns.
@@ -479,10 +519,10 @@ ScaleFactor KBPKScalingFunction::apply(const Position &pos) {
ScaleFactor KQKRPScalingFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(strongerSide) == QueenValueMidgame);
- assert(pos.queen_count(strongerSide) == 1);
- assert(pos.pawn_count(strongerSide) == 0);
- assert(pos.rook_count(weakerSide) == 1);
- assert(pos.pawn_count(weakerSide) >= 1);
+ assert(pos.piece_count(strongerSide, QUEEN) == 1);
+ assert(pos.piece_count(strongerSide, PAWN) == 0);
+ assert(pos.piece_count(weakerSide, ROOK) == 1);
+ assert(pos.piece_count(weakerSide, PAWN) >= 1);
Square kingSq = pos.king_square(weakerSide);
if(relative_rank(weakerSide, kingSq) <= RANK_2 &&
@@ -508,9 +548,9 @@ ScaleFactor KQKRPScalingFunction::apply(const Position &pos) {
ScaleFactor KRPKRScalingFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
- assert(pos.pawn_count(strongerSide) == 1);
+ assert(pos.piece_count(strongerSide, PAWN) == 1);
assert(pos.non_pawn_material(weakerSide) == RookValueMidgame);
- assert(pos.pawn_count(weakerSide) == 0);
+ assert(pos.piece_count(weakerSide, PAWN) == 0);
Square wksq = pos.king_square(strongerSide);
Square wrsq = pos.piece_list(strongerSide, ROOK, 0);
@@ -603,6 +643,16 @@ ScaleFactor KRPKRScalingFunction::apply(const Position &pos) {
- (8 * square_distance(wpsq, queeningSq) +
2 * square_distance(wksq, queeningSq)));
+ // If the pawn is not far advanced, and the defending king is somewhere in
+ // the pawn's path, it's probably a draw:
+ if(r <= RANK_4 && bksq > wpsq) {
+ if(square_file(bksq) == square_file(wpsq))
+ return ScaleFactor(10);
+ if(abs(square_file(bksq) - square_file(wpsq)) == 1
+ && square_distance(wksq, bksq) > 2)
+ return ScaleFactor(24 - 2 * square_distance(wksq, bksq));
+ }
+
return SCALE_FACTOR_NONE;
}
@@ -613,9 +663,9 @@ ScaleFactor KRPKRScalingFunction::apply(const Position &pos) {
ScaleFactor KRPPKRPScalingFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(strongerSide) == RookValueMidgame);
- assert(pos.pawn_count(strongerSide) == 2);
+ assert(pos.piece_count(strongerSide, PAWN) == 2);
assert(pos.non_pawn_material(weakerSide) == RookValueMidgame);
- assert(pos.pawn_count(weakerSide) == 1);
+ assert(pos.piece_count(weakerSide, PAWN) == 1);
Square wpsq1 = pos.piece_list(strongerSide, PAWN, 0);
Square wpsq2 = pos.piece_list(strongerSide, PAWN, 1);
@@ -651,9 +701,9 @@ ScaleFactor KRPPKRPScalingFunction::apply(const Position &pos) {
ScaleFactor KPsKScalingFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(strongerSide) == Value(0));
- assert(pos.pawn_count(strongerSide) >= 2);
+ assert(pos.piece_count(strongerSide, PAWN) >= 2);
assert(pos.non_pawn_material(weakerSide) == Value(0));
- assert(pos.pawn_count(weakerSide) == 0);
+ assert(pos.piece_count(weakerSide, PAWN) == 0);
Bitboard pawns = pos.pawns(strongerSide);
@@ -694,11 +744,11 @@ ScaleFactor KPsKScalingFunction::apply(const Position &pos) {
ScaleFactor KBPKBScalingFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame);
- assert(pos.bishop_count(strongerSide) == 1);
- assert(pos.pawn_count(strongerSide) == 1);
+ assert(pos.piece_count(strongerSide, BISHOP) == 1);
+ assert(pos.piece_count(strongerSide, PAWN) == 1);
assert(pos.non_pawn_material(weakerSide) == BishopValueMidgame);
- assert(pos.bishop_count(weakerSide) == 1);
- assert(pos.pawn_count(weakerSide) == 0);
+ assert(pos.piece_count(weakerSide, BISHOP) == 1);
+ assert(pos.piece_count(weakerSide, PAWN) == 0);
Square pawnSq = pos.piece_list(strongerSide, PAWN, 0);
Square strongerBishopSq = pos.piece_list(strongerSide, BISHOP, 0);
@@ -714,9 +764,9 @@ ScaleFactor KBPKBScalingFunction::apply(const Position &pos) {
// Case 2: Opposite colored bishops.
if(square_color(strongerBishopSq) != square_color(weakerBishopSq)) {
-
+
// We assume that the position is drawn in the following three situations:
- //
+ //
// a. The pawn is on rank 5 or further back.
// b. The defending king is somewhere in the pawn's path.
// c. The defending bishop attacks some square along the pawn's path,
@@ -724,7 +774,7 @@ ScaleFactor KBPKBScalingFunction::apply(const Position &pos) {
//
// These rules are probably not perfect, but in practice they work
// reasonably well.
-
+
if(relative_rank(strongerSide, pawnSq) <= RANK_5)
return ScaleFactor(0);
else {
@@ -748,16 +798,16 @@ ScaleFactor KBPKBScalingFunction::apply(const Position &pos) {
ScaleFactor KBPKNScalingFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(strongerSide) == BishopValueMidgame);
- assert(pos.bishop_count(strongerSide) == 1);
- assert(pos.pawn_count(strongerSide) == 1);
+ assert(pos.piece_count(strongerSide, BISHOP) == 1);
+ assert(pos.piece_count(strongerSide, PAWN) == 1);
assert(pos.non_pawn_material(weakerSide) == KnightValueMidgame);
- assert(pos.knight_count(weakerSide) == 1);
- assert(pos.pawn_count(weakerSide) == 0);
+ assert(pos.piece_count(weakerSide, KNIGHT) == 1);
+ assert(pos.piece_count(weakerSide, PAWN) == 0);
Square pawnSq = pos.piece_list(strongerSide, PAWN, 0);
Square strongerBishopSq = pos.piece_list(strongerSide, BISHOP, 0);
Square weakerKingSq = pos.king_square(weakerSide);
-
+
if(square_file(weakerKingSq) == square_file(pawnSq)
&& relative_rank(strongerSide, pawnSq) < relative_rank(strongerSide, weakerKingSq)
&& (square_color(weakerKingSq) != square_color(strongerBishopSq)
@@ -774,10 +824,10 @@ ScaleFactor KBPKNScalingFunction::apply(const Position &pos) {
ScaleFactor KNPKScalingFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(strongerSide) == KnightValueMidgame);
- assert(pos.knight_count(strongerSide) == 1);
- assert(pos.pawn_count(strongerSide) == 1);
+ assert(pos.piece_count(strongerSide, KNIGHT) == 1);
+ assert(pos.piece_count(strongerSide, PAWN) == 1);
assert(pos.non_pawn_material(weakerSide) == Value(0));
- assert(pos.pawn_count(weakerSide) == 0);
+ assert(pos.piece_count(weakerSide, PAWN) == 0);
Square pawnSq = pos.piece_list(strongerSide, PAWN, 0);
Square weakerKingSq = pos.king_square(weakerSide);
@@ -804,8 +854,8 @@ ScaleFactor KNPKScalingFunction::apply(const Position &pos) {
ScaleFactor KPKPScalingFunction::apply(const Position &pos) {
assert(pos.non_pawn_material(strongerSide) == Value(0));
assert(pos.non_pawn_material(weakerSide) == Value(0));
- assert(pos.pawn_count(WHITE) == 1);
- assert(pos.pawn_count(BLACK) == 1);
+ assert(pos.piece_count(WHITE, PAWN) == 1);
+ assert(pos.piece_count(BLACK, PAWN) == 1);
Square wksq, bksq, wpsq;
Color stm;
@@ -859,9 +909,9 @@ namespace {
int probe_kpk(Square wksq, Square wpsq, Square bksq, Color stm) {
int wp = int(square_file(wpsq)) + (int(square_rank(wpsq)) - 1) * 4;
int index = int(stm) + 2*int(bksq) + 128*int(wksq) + 8192*wp;
-
+
assert(index >= 0 && index < 24576*8);
return KPKBitbase[index/8] & (1 << (index&7));
}
-
+
}