/*
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
// 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)
const Score TrappedRook = S(92, 0);
const Score Unstoppable = S( 0, 20);
const Score Hanging = S(31, 26);
+ const Score PawnAttackThreat = S(20, 20);
// 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
// scores, indexed by a calculated integer number.
- Score KingDanger[128];
+ Score KingDanger[512];
// apply_weight() weighs score 's' by weight 'w' trying to prevent overflow
Score apply_weight(Score s, const Weight& w) {
// 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) * 31 / 256
- !pos.count<QUEEN>(Them) * 60;
// Analyse the enemy's safe queen contact checks. Firstly, find the
// Finally, extract the king danger score from the KingDanger[]
// array and subtract the score from evaluation.
- score -= KingDanger[std::max(std::min(attackUnits / 4, 99), 0)];
+ score -= KingDanger[std::max(std::min(attackUnits, 399), 0)];
}
if (Trace)
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 bonus for safe pawn pushes which attacks an enemy piece
+ 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][PAWN] | ~ei.attackedBy[Them][ALL_PIECES]);
+
+ 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 = 30;
- const double Peak = 1280;
+ const int MaxSlope = 87;
+ const int Peak = 12800;
+ int t = 0;
- for (int t = 0, i = 1; i < 100; ++i)
+ for (int i = 0; i < 400; ++i)
{
- t = int(std::min(Peak, std::min(0.4 * i * i, t + MaxSlope)));
- KingDanger[i] = apply_weight(make_score(t, 0), Weights[KingSafety]);
+ t = std::min(Peak, std::min(i * i * 27 / 100, t + MaxSlope));
+ KingDanger[i] = apply_weight(make_score(t / 10, 0), Weights[KingSafety]);
}
}