/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, 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
// KingAttackWeights array.
int kingAttackersWeight[COLOR_NB];
- // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
- // directly adjacent to the king of the given color. Pieces which attack
- // more than one square are counted multiple times. For instance, if black's
- // king is on g8 and there's a white knight on g5, this knight adds
- // 2 to kingAdjacentZoneAttacksCount[BLACK].
+ // kingAdjacentZoneAttacksCount[color] is the number of attacks by the given
+ // color to squares directly adjacent to the enemy king. Pieces which attack
+ // more than one square are counted multiple times. For instance, if there is
+ // a white knight on g5 and black's king is on g8, this white knight adds 2
+ // to kingAdjacentZoneAttacksCount[WHITE].
int kingAdjacentZoneAttacksCount[COLOR_NB];
Bitboard pinnedPieces[COLOR_NB];
// Evaluation weights, indexed by evaluation term
enum { Mobility, PawnStructure, PassedPawns, Space, KingSafety };
const struct Weight { int mg, eg; } Weights[] = {
- {289, 344}, {233, 201}, {221, 273}, {46, 0}, {321, 0}
+ {289, 344}, {233, 201}, {221, 273}, {46, 0}, {322, 0}
};
#define V(v) Value(v)
// ThreatenedByPawn[PieceType] contains a penalty according to which piece
// type is attacked by an enemy pawn.
const Score ThreatenedByPawn[] = {
- S(0, 0), S(0, 0), S(87, 118), S(84, 122), S(114, 203), S(121, 217)
+ S(0, 0), S(0, 0), S(107, 138), S(84, 122), S(114, 203), S(121, 217)
};
// Assorted bonuses and penalties used by evaluation
const Score TrappedRook = S(92, 0);
const Score Unstoppable = S( 0, 20);
const Score Hanging = S(31, 26);
+ const Score PawnAttackThreat = S(20, 20);
+ const Score PawnSafePush = S( 5, 5);
// Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
// a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
// index to KingDanger[].
//
// KingAttackWeights[PieceType] contains king attack weights by piece type
- const int KingAttackWeights[] = { 0, 0, 6, 2, 5, 5 };
+ const int KingAttackWeights[] = { 0, 0, 7, 5, 4, 1 };
// Bonuses for enemy's safe checks
- const int QueenContactCheck = 92;
- const int RookContactCheck = 68;
+ const int QueenContactCheck = 89;
+ const int RookContactCheck = 71;
const int QueenCheck = 50;
- const int RookCheck = 36;
- const int BishopCheck = 7;
+ const int RookCheck = 37;
+ const int BishopCheck = 6;
const int KnightCheck = 14;
// KingDanger[attackUnits] contains the actual king danger weighted
// number and types of the enemy's attacking pieces, the number of
// attacked and undefended squares around our king and the quality of
// the pawn shelter (current 'score' value).
- attackUnits = std::min(77, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
- + 10 * ei.kingAdjacentZoneAttacksCount[Them]
- + 19 * popcount<Max15>(undefended)
- + 9 * (ei.pinnedPieces[Us] != 0)
- - mg_value(score) * 63 / 512
+ attackUnits = std::min(74, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
+ + 8 * ei.kingAdjacentZoneAttacksCount[Them]
+ + 25 * popcount<Max15>(undefended)
+ + 11 * (ei.pinnedPieces[Us] != 0)
+ - mg_value(score) / 8
- !pos.count<QUEEN>(Them) * 60;
// Analyse the enemy's safe queen contact checks. Firstly, find the
template<Color Us, bool Trace>
Score evaluate_threats(const Position& pos, const EvalInfo& ei) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Square Up = (Us == WHITE ? DELTA_N : DELTA_S);
+ const Square Left = (Us == WHITE ? DELTA_NW : DELTA_SE);
+ const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW);
+ const Bitboard TRank2BB = (Us == WHITE ? Rank2BB : Rank7BB);
+ const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
enum { Defended, Weak };
enum { Minor, Major };
b = weak & ~ei.attackedBy[Them][ALL_PIECES];
if (b)
- score += more_than_one(b) ? Hanging * popcount<Max15>(b) : Hanging;
+ score += Hanging * popcount<Max15>(b);
b = weak & ei.attackedBy[Us][KING];
if (b)
score += more_than_one(b) ? KingOnMany : KingOnOne;
}
+ // Add a small bonus for safe pawn pushes
+ b = pos.pieces(Us, PAWN) & ~TRank7BB;
+ b = shift_bb<Up>(b | (shift_bb<Up>(b & TRank2BB) & ~pos.pieces()));
+
+ b &= ~pos.pieces()
+ & ~ei.attackedBy[Them][PAWN]
+ & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
+
+ if (b)
+ score += popcount<Full>(b) * PawnSafePush;
+
+ // Add another bonus if the pawn push attacks an enemy piece
+ b = (shift_bb<Left>(b) | shift_bb<Right>(b))
+ & pos.pieces(Them)
+ & ~ei.attackedBy[Us][PAWN];
+
+ if (b)
+ score += popcount<Max15>(b) * PawnAttackThreat;
+
if (Trace)
Tracing::write(Tracing::THREAT, Us, score);
void init() {
- const double MaxSlope = 7.5;
- const double Peak = 1280;
- double t = 0.0;
+ const int MaxSlope = 8700;
+ const int Peak = 1280000;
+ int t = 0;
- for (int i = 1; i < 400; ++i)
+ for (int i = 0; i < 400; ++i)
{
- t = std::min(Peak, std::min(0.025 * i * i, t + MaxSlope));
- KingDanger[i] = apply_weight(make_score(int(t), 0), Weights[KingSafety]);
+ t = std::min(Peak, std::min(i * i * 27, t + MaxSlope));
+ KingDanger[i] = apply_weight(make_score(t / 1000, 0), Weights[KingSafety]);
}
}