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Merged two new endgames from Glaurung 2.2

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It is two bishop against a knight and two minor
pieces against one minor piece.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2008-12-21 15:38:10 +01:00
parent 72ca727b38
commit f178f0a291
3 changed files with 87 additions and 0 deletions
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49
src/endgame.cpp
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@@ -62,6 +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
@@ -187,6 +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) {
@@ -420,6 +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<KNIGHT>(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
@@ -604,6 +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;
}