const int GrainSize = 8;
// Evaluation weights, initialized from UCI options
- Score WeightMobility, WeightPawnStructure;
- Score WeightPassedPawns, WeightSpace;
- Score WeightKingSafety[2];
+ enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem };
+ Score Weights[6];
+
+ typedef Value V;
+ #define S(mg, eg) make_score(mg, eg)
// Internal evaluation weights. These are applied on top of the evaluation
// weights read from UCI parameters. The purpose is to be able to change
// parameters at 100, which looks prettier.
//
// Values modified by Joona Kiiski
- const Score WeightMobilityInternal = make_score(248, 271);
- const Score WeightPawnStructureInternal = make_score(233, 201);
- const Score WeightPassedPawnsInternal = make_score(252, 259);
- const Score WeightSpaceInternal = make_score( 46, 0);
- const Score WeightKingSafetyInternal = make_score(247, 0);
- const Score WeightKingOppSafetyInternal = make_score(259, 0);
-
- // Mobility and outposts bonus modified by Joona Kiiski
-
- typedef Value V;
- #define S(mg, eg) make_score(mg, eg)
-
- CACHE_LINE_ALIGNMENT
+ const Score WeightsInternal[] = {
+ S(248, 271), S(233, 201), S(252, 259), S(46, 0), S(247, 0), S(259, 0)
+ };
// Knight mobility bonus in middle game and endgame, indexed by the number
// of attacked squares not occupied by friendly piecess.
V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8
};
- // ThreatBonus[][] contains bonus according to which piece type
- // attacks which one.
- #define Z S(0, 0)
-
+ // ThreatBonus[attacking][attacked] contains bonus according to which
+ // piece type attacks which one.
const Score ThreatBonus[8][8] = {
- { Z, Z, Z, Z, Z, Z, Z, Z }, // not used
- { Z, S(18,37), Z, S(37,47), S(55,97), S(55,97), Z, Z }, // KNIGHT attacks
- { Z, S(18,37), S(37,47), Z, S(55,97), S(55,97), Z, Z }, // BISHOP attacks
- { Z, S( 9,27), S(27,47), S(27,47), Z, S(37,47), Z, Z }, // ROOK attacks
- { Z, S(27,37), S(27,37), S(27,37), S(27,37), Z, Z, Z }, // QUEEN attacks
- { Z, Z, Z, Z, Z, Z, Z, Z }, // not used
- { Z, Z, Z, Z, Z, Z, Z, Z }, // not used
- { Z, Z, Z, Z, Z, Z, Z, Z } // not used
+ {}, {},
+ { S(0, 0), S( 7, 39), S( 0, 0), S(24, 49), S(41,100), S(41,100) }, // KNIGHT
+ { S(0, 0), S( 7, 39), S(24, 49), S( 0, 0), S(41,100), S(41,100) }, // BISHOP
+ { S(0, 0), S(-1, 29), S(15, 49), S(15, 49), S( 0, 0), S(24, 49) }, // ROOK
+ { S(0, 0), S(15, 39), S(15, 39), S(15, 39), S(15, 39), S( 0, 0) } // QUEEN
};
// ThreatedByPawnPenalty[] contains a penalty according to which piece
// type is attacked by an enemy pawn.
const Score ThreatedByPawnPenalty[8] = {
- Z, Z, S(56, 70), S(56, 70), S(76, 99), S(86, 118), Z, Z
+ S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
};
- #undef Z
#undef S
// Bonus for unstoppable passed pawns
(1ULL<<SQ_C5) | (1ULL<<SQ_D5) | (1ULL<<SQ_E5) | (1ULL<<SQ_F5)
};
- /// King safety constants and variables. The king safety scores are taken
- /// from the array SafetyTable[]. Various little "meta-bonuses" measuring
- /// the strength of the attack are added up into an integer, which is used
- /// as an index to SafetyTable[].
+ /// King danger constants and variables. The king danger scores are taken
+ /// from the KingDangerTable[]. Various little "meta-bonuses" measuring
+ /// the strength of the enemy attack are added up into an integer, which
+ /// is used as an index to KingDangerTable[].
- // Attack weights for each piece type and table indexed on piece type
- const int QueenAttackWeight = 5;
- const int RookAttackWeight = 3;
- const int BishopAttackWeight = 2;
- const int KnightAttackWeight = 2;
+ // KingAttackWeights[] contains king attack weights by piece type
+ const int KingAttackWeights[8] = { 0, 0, 2, 2, 3, 5 };
- const int AttackWeight[] = { 0, 0, KnightAttackWeight, BishopAttackWeight, RookAttackWeight, QueenAttackWeight };
-
- // Bonuses for safe checks
+ // Bonuses for enemy's safe checks
const int QueenContactCheckBonus = 3;
const int DiscoveredCheckBonus = 3;
- const int QueenCheckBonus = 2;
+ const int QueenCheckBonus = 2;
const int RookCheckBonus = 1;
- const int BishopCheckBonus = 1;
+ const int BishopCheckBonus = 1;
const int KnightCheckBonus = 1;
- // Scan for queen contact mates?
- const bool QueenContactMates = true;
-
- // Bonus for having a mate threat
- const int MateThreatBonus = 3;
-
// InitKingDanger[] contains bonuses based on the position of the defending
// king.
const int InitKingDanger[64] = {
15, 15, 15, 15, 15, 15, 15, 15
};
- // SafetyTable[] contains the actual king safety scores. It is initialized
- // in init_safety().
- Value SafetyTable[100];
+ // KingDangerTable[color][] contains the actual king danger weighted scores
+ Score KingDangerTable[2][128];
// Pawn and material hash tables, indexed by the current thread id.
// Note that they will be initialized at 0 being global variables.
template<bool HasPopCnt>
Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID);
+ template<Color Us, bool HasPopCnt>
+ void init_attack_tables(const Position& pos, EvalInfo& ei);
+
template<Color Us, bool HasPopCnt>
void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei);
template<Color Us, bool HasPopCnt>
void evaluate_space(const Position& pos, EvalInfo& ei);
+ template<Color Us>
void evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
+
+ void evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo& ei);
void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei);
inline Score apply_weight(Score v, Score weight);
template<bool HasPopCnt>
Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID) {
+ ScaleFactor factor[2];
+
assert(pos.is_ok());
assert(threadID >= 0 && threadID < MAX_THREADS);
assert(!pos.is_check());
return ei.mi->evaluate(pos);
// After get_material_info() call that modifies them
- ScaleFactor factor[2];
factor[WHITE] = ei.mi->scale_factor(pos, WHITE);
factor[BLACK] = ei.mi->scale_factor(pos, BLACK);
// Probe the pawn hash table
ei.pi = PawnTable[threadID]->get_pawn_info(pos);
- ei.value += apply_weight(ei.pi->pawns_value(), WeightPawnStructure);
-
- // Initialize king attack bitboards and king attack zones for both sides
- ei.attackedBy[WHITE][KING] = pos.attacks_from<KING>(pos.king_square(WHITE));
- ei.attackedBy[BLACK][KING] = pos.attacks_from<KING>(pos.king_square(BLACK));
- ei.kingZone[WHITE] = ei.attackedBy[BLACK][KING] | (ei.attackedBy[BLACK][KING] >> 8);
- ei.kingZone[BLACK] = ei.attackedBy[WHITE][KING] | (ei.attackedBy[WHITE][KING] << 8);
-
- // Initialize pawn attack bitboards for both sides
- ei.attackedBy[WHITE][PAWN] = ei.pi->pawn_attacks(WHITE);
- ei.attackedBy[BLACK][PAWN] = ei.pi->pawn_attacks(BLACK);
- Bitboard b1 = ei.attackedBy[WHITE][PAWN] & ei.attackedBy[BLACK][KING];
- Bitboard b2 = ei.attackedBy[BLACK][PAWN] & ei.attackedBy[WHITE][KING];
- if (b1)
- ei.kingAttackersCount[WHITE] = count_1s_max_15<HasPopCnt>(b1)/2;
+ ei.value += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
- if (b2)
- ei.kingAttackersCount[BLACK] = count_1s_max_15<HasPopCnt>(b2)/2;
+ // Initialize attack bitboards with pawns evaluation
+ init_attack_tables<WHITE, HasPopCnt>(pos, ei);
+ init_attack_tables<BLACK, HasPopCnt>(pos, ei);
// Evaluate pieces
evaluate_pieces_of_color<WHITE, HasPopCnt>(pos, ei);
evaluate_king<WHITE, HasPopCnt>(pos, ei);
evaluate_king<BLACK, HasPopCnt>(pos, ei);
- // Evaluate tactical threats, we need full attack info
+ // Evaluate tactical threats, we need full attack info including king
evaluate_threats<WHITE>(pos, ei);
evaluate_threats<BLACK>(pos, ei);
- // Evaluate passed pawns. We evaluate passed pawns for both sides at once,
- // because we need to know which side promotes first in positions where
- // both sides have an unstoppable passed pawn. To be called after all attacks
- // are computed, included king.
- if (ei.pi->passed_pawns())
- evaluate_passed_pawns(pos, ei);
+ // Evaluate passed pawns, we need full attack info including king
+ evaluate_passed_pawns<WHITE>(pos, ei);
+ evaluate_passed_pawns<BLACK>(pos, ei);
+
+ // If one side has only a king, check whether exsists any unstoppable passed pawn
+ if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
+ evaluate_unstoppable_pawns(pos, ei);
Phase phase = ei.mi->game_phase();
// Middle-game specific evaluation terms
if (phase > PHASE_ENDGAME)
{
- // Pawn storms in positions with opposite castling.
+ // Pawn storms in positions with opposite castling
if ( square_file(pos.king_square(WHITE)) >= FILE_E
&& square_file(pos.king_square(BLACK)) <= FILE_D)
}
// Mobility
- ei.value += apply_weight(ei.mobility, WeightMobility);
+ ei.value += apply_weight(ei.mobility, Weights[Mobility]);
// If we don't already have an unusual scale factor, check for opposite
// colored bishop endgames, and use a lower scale for those
}
// Interpolate between the middle game and the endgame score
- Color stm = pos.side_to_move();
-
- Value v = Sign[stm] * scale_by_game_phase(ei.value, phase, factor);
-
- return (ei.mateThreat[stm] == MOVE_NONE ? v : 8 * QueenValueMidgame - v);
+ return Sign[pos.side_to_move()] * scale_by_game_phase(ei.value, phase, factor);
}
} // namespace
void read_weights(Color us) {
- Color them = opposite_color(us);
+ // King safety is asymmetrical. Our king danger level is weighted by
+ // "Cowardice" UCI parameter, instead the opponent one by "Aggressiveness".
+ const int kingDangerUs = (us == WHITE ? KingDangerUs : KingDangerThem);
+ const int kingDangerThem = (us == WHITE ? KingDangerThem : KingDangerUs);
- WeightMobility = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightMobilityInternal);
- WeightPawnStructure = weight_option("Pawn Structure (Middle Game)", "Pawn Structure (Endgame)", WeightPawnStructureInternal);
- WeightPassedPawns = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightPassedPawnsInternal);
- WeightSpace = weight_option("Space", "Space", WeightSpaceInternal);
- WeightKingSafety[us] = weight_option("Cowardice", "Cowardice", WeightKingSafetyInternal);
- WeightKingSafety[them] = weight_option("Aggressiveness", "Aggressiveness", WeightKingOppSafetyInternal);
+ Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
+ Weights[PawnStructure] = weight_option("Pawn Structure (Middle Game)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
+ Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
+ Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
+ Weights[kingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
+ Weights[kingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
// If running in analysis mode, make sure we use symmetrical king safety. We do this
- // by replacing both WeightKingSafety[us] and WeightKingSafety[them] by their average.
+ // by replacing both Weights[kingDangerUs] and Weights[kingDangerThem] by their average.
if (get_option_value_bool("UCI_AnalyseMode"))
- {
- WeightKingSafety[us] = (WeightKingSafety[us] + WeightKingSafety[them]) / 2;
- WeightKingSafety[them] = WeightKingSafety[us];
- }
+ Weights[kingDangerUs] = Weights[kingDangerThem] = (Weights[kingDangerUs] + Weights[kingDangerThem]) / 2;
+
init_safety();
}
namespace {
+ // init_king_tables() initializes king bitboards for both sides adding
+ // pawn attacks. To be done before other evaluations.
+
+ template<Color Us, bool HasPopCnt>
+ void init_attack_tables(const Position& pos, EvalInfo& ei) {
+
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+
+ Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
+ ei.kingZone[Us] = (b | (Us == WHITE ? b >> 8 : b << 8));
+ ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
+ b &= ei.attackedBy[Us][PAWN];
+ if (b)
+ ei.kingAttackersCount[Us] = count_1s_max_15<HasPopCnt>(b) / 2;
+ }
+
+
// evaluate_outposts() evaluates bishop and knight outposts squares
template<PieceType Piece, Color Us>
if (b & ei.kingZone[Us])
{
ei.kingAttackersCount[Us]++;
- ei.kingAttackersWeight[Us] += AttackWeight[Piece];
+ ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
Bitboard bb = (b & ei.attackedBy[Them][KING]);
if (bb)
ei.kingAdjacentZoneAttacksCount[Us] += count_1s_max_15<HasPopCnt>(bb);
ei.value -= Sign[Us] * ThreatedByPawnPenalty[Piece];
// Bishop and knight outposts squares
- if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Them))
+ if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Us))
evaluate_outposts<Piece, Us>(pos, ei, s);
// Special patterns: trapped bishops on a7/h7/a2/h2
const Color Them = (Us == WHITE ? BLACK : WHITE);
- Bitboard undefended, attackedByOthers, escapeSquares, occ, b, b2, safe;
- Square from, to;
+ Bitboard undefended, b, b1, b2, safe;
bool sente;
- int attackUnits, count, shelter = 0;
- const Square s = pos.king_square(Us);
+ int attackUnits, shelter = 0;
+ const Square ksq = pos.king_square(Us);
// King shelter
- if (relative_rank(Us, s) <= RANK_4)
+ if (relative_rank(Us, ksq) <= RANK_4)
{
- shelter = ei.pi->get_king_shelter(pos, Us, s);
+ shelter = ei.pi->get_king_shelter(pos, Us, ksq);
ei.value += Sign[Us] * make_score(shelter, 0);
}
// King safety. This is quite complicated, and is almost certainly far
// from optimally tuned.
if ( pos.piece_count(Them, QUEEN) >= 1
- && ei.kingAttackersCount[Them] >= 2
- && pos.non_pawn_material(Them) >= QueenValueMidgame + RookValueMidgame
+ && ei.kingAttackersCount[Them] >= 2
+ && pos.non_pawn_material(Them) >= QueenValueMidgame + RookValueMidgame
&& ei.kingAdjacentZoneAttacksCount[Them])
{
- // Is it the attackers turn to move?
- sente = (Them == pos.side_to_move());
-
- // Find the attacked squares around the king which has no defenders
- // apart from the king itself
- undefended = ei.attacked_by(Them) & ei.attacked_by(Us, KING);
- undefended &= ~( ei.attacked_by(Us, PAWN) | ei.attacked_by(Us, KNIGHT)
- | ei.attacked_by(Us, BISHOP) | ei.attacked_by(Us, ROOK)
- | ei.attacked_by(Us, QUEEN));
-
- // Initialize the 'attackUnits' variable, which is used later on as an
- // index to the SafetyTable[] array. The initial value is based on the
- // number and types of the attacking pieces, the number of attacked and
- // undefended squares around the king, the square of the king, and the
- // quality of the pawn shelter.
- attackUnits = Min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
- + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + count_1s_max_15<HasPopCnt>(undefended))
- + InitKingDanger[relative_square(Us, s)]
- - (shelter >> 5);
-
- // Analyse safe queen contact checks
- b = undefended & ei.attacked_by(Them, QUEEN) & ~pos.pieces_of_color(Them);
- if (b)
- {
- attackedByOthers = ei.attacked_by(Them, PAWN) | ei.attacked_by(Them, KNIGHT)
- | ei.attacked_by(Them, BISHOP) | ei.attacked_by(Them, ROOK);
-
- b &= attackedByOthers;
-
- // Squares attacked by the queen and supported by another enemy piece and
- // not defended by other pieces but our king.
+ // Is it the attackers turn to move?
+ sente = (Them == pos.side_to_move());
+
+ // Find the attacked squares around the king which has no defenders
+ // apart from the king itself
+ undefended = ei.attacked_by(Them) & ei.attacked_by(Us, KING);
+ undefended &= ~( ei.attacked_by(Us, PAWN) | ei.attacked_by(Us, KNIGHT)
+ | ei.attacked_by(Us, BISHOP) | ei.attacked_by(Us, ROOK)
+ | ei.attacked_by(Us, QUEEN));
+
+ // Initialize the 'attackUnits' variable, which is used later on as an
+ // index to the KingDangerTable[] array. The initial value is based on
+ // the number and types of the enemy's attacking pieces, the number of
+ // attacked and undefended squares around our king, the square of the
+ // king, and the quality of the pawn shelter.
+ attackUnits = Min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
+ + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + count_1s_max_15<HasPopCnt>(undefended))
+ + InitKingDanger[relative_square(Us, ksq)]
+ - shelter / 32;
+
+ // Analyse enemy's safe queen contact checks. First find undefended
+ // squares around the king attacked by enemy queen...
+ b = undefended & ei.attacked_by(Them, QUEEN) & ~pos.pieces_of_color(Them);
if (b)
{
- // The bitboard b now contains the squares available for safe queen
- // contact checks.
- count = count_1s_max_15<HasPopCnt>(b);
- attackUnits += QueenContactCheckBonus * count * (sente ? 2 : 1);
-
- // Is there a mate threat?
- if (QueenContactMates && !pos.is_check())
- {
- escapeSquares = pos.attacks_from<KING>(s) & ~pos.pieces_of_color(Us) & ~attackedByOthers;
- occ = pos.occupied_squares();
- while (b)
- {
- to = pop_1st_bit(&b);
-
- // Do we have escape squares from queen contact check attack ?
- if (!(escapeSquares & ~queen_attacks_bb(to, occ & ClearMaskBB[s])))
- {
- // We have a mate, unless the queen is pinned or there
- // is an X-ray attack through the queen.
- for (int i = 0; i < pos.piece_count(Them, QUEEN); i++)
- {
- from = pos.piece_list(Them, QUEEN, i);
- if ( bit_is_set(pos.attacks_from<QUEEN>(from), to)
- && !bit_is_set(pos.pinned_pieces(Them), from)
- && !(rook_attacks_bb(to, occ & ClearMaskBB[from]) & pos.pieces(ROOK, QUEEN, Us))
- && !(bishop_attacks_bb(to, occ & ClearMaskBB[from]) & pos.pieces(BISHOP, QUEEN, Us)))
-
- // Set the mate threat move
- ei.mateThreat[Them] = make_move(from, to);
- }
- }
- }
- }
+ // ...then remove squares not supported by another enemy piece
+ b &= ( ei.attacked_by(Them, PAWN) | ei.attacked_by(Them, KNIGHT)
+ | ei.attacked_by(Them, BISHOP) | ei.attacked_by(Them, ROOK));
+ if (b)
+ attackUnits += QueenContactCheckBonus * count_1s_max_15<HasPopCnt>(b) * (sente ? 2 : 1);
}
- }
-
- // Analyse safe distance checks
- safe = ~(pos.pieces_of_color(Them) | ei.attacked_by(Us));
-
- if (QueenCheckBonus > 0 || RookCheckBonus > 0)
- {
- b = pos.attacks_from<ROOK>(s) & safe;
-
- // Queen checks
- b2 = b & ei.attacked_by(Them, QUEEN);
- if (b2)
- attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b2);
- // Rook checks
- b2 = b & ei.attacked_by(Them, ROOK);
- if (b2)
- attackUnits += RookCheckBonus * count_1s_max_15<HasPopCnt>(b2);
- }
- if (QueenCheckBonus > 0 || BishopCheckBonus > 0)
- {
- b = pos.attacks_from<BISHOP>(s) & safe;
+ // Analyse enemy's safe distance checks for sliders and knights
+ safe = ~(pos.pieces_of_color(Them) | ei.attacked_by(Us));
- // Queen checks
- b2 = b & ei.attacked_by(Them, QUEEN);
- if (b2)
- attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b2);
+ b1 = pos.attacks_from<ROOK>(ksq) & safe;
+ b2 = pos.attacks_from<BISHOP>(ksq) & safe;
- // Bishop checks
- b2 = b & ei.attacked_by(Them, BISHOP);
- if (b2)
- attackUnits += BishopCheckBonus * count_1s_max_15<HasPopCnt>(b2);
- }
- if (KnightCheckBonus > 0)
- {
- b = pos.attacks_from<KNIGHT>(s) & safe;
+ // Enemy queen safe checks
+ b = (b1 | b2) & ei.attacked_by(Them, QUEEN);
+ if (b)
+ attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b);
- // Knight checks
- b2 = b & ei.attacked_by(Them, KNIGHT);
- if (b2)
- attackUnits += KnightCheckBonus * count_1s_max_15<HasPopCnt>(b2);
- }
+ // Enemy rooks safe checks
+ b = b1 & ei.attacked_by(Them, ROOK);
+ if (b)
+ attackUnits += RookCheckBonus * count_1s_max_15<HasPopCnt>(b);
- // Analyse discovered checks (only for non-pawns right now, consider
- // adding pawns later).
- if (DiscoveredCheckBonus)
- {
- b = pos.discovered_check_candidates(Them) & ~pos.pieces(PAWN);
- if (b)
- attackUnits += DiscoveredCheckBonus * count_1s_max_15<HasPopCnt>(b) * (sente ? 2 : 1);
- }
+ // Enemy bishops safe checks
+ b = b2 & ei.attacked_by(Them, BISHOP);
+ if (b)
+ attackUnits += BishopCheckBonus * count_1s_max_15<HasPopCnt>(b);
- // Has a mate threat been found? We don't do anything here if the
- // side with the mating move is the side to move, because in that
- // case the mating side will get a huge bonus at the end of the main
- // evaluation function instead.
- if (ei.mateThreat[Them] != MOVE_NONE)
- attackUnits += MateThreatBonus;
-
- // Ensure that attackUnits is between 0 and 99, in order to avoid array
- // out of bounds errors.
- attackUnits = Min(99, Max(0, attackUnits));
-
- // Finally, extract the king safety score from the SafetyTable[] array.
- // Add the score to the evaluation, and also to ei.futilityMargin. The
- // reason for adding the king safety score to the futility margin is
- // that the king safety scores can sometimes be very big, and that
- // capturing a single attacking piece can therefore result in a score
- // change far bigger than the value of the captured piece.
- Score v = apply_weight(make_score(SafetyTable[attackUnits], 0), WeightKingSafety[Us]);
- ei.value -= Sign[Us] * v;
- ei.futilityMargin[Us] += mg_value(v);
+ // Enemy knights safe checks
+ b = pos.attacks_from<KNIGHT>(ksq) & ei.attacked_by(Them, KNIGHT) & safe;
+ if (b)
+ attackUnits += KnightCheckBonus * count_1s_max_15<HasPopCnt>(b);
+
+ // To index KingDangerTable[] attackUnits must be in [0, 99] range
+ attackUnits = Min(99, Max(0, attackUnits));
+
+ // Finally, extract the king danger score from the KingDangerTable[]
+ // array and subtract the score from evaluation. Set also ei.kingDanger[]
+ // value that will be used for pruning because this value can sometimes
+ // be very big, and so capturing a single attacking piece can therefore
+ // result in a score change far bigger than the value of the captured piece.
+ ei.value -= Sign[Us] * KingDangerTable[Us][attackUnits];
+ ei.kingDanger[Us] = mg_value(KingDangerTable[Us][attackUnits]);
}
}
- // evaluate_passed_pawns_of_color() evaluates the passed pawns of the given color
+ // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
template<Color Us>
- void evaluate_passed_pawns_of_color(const Position& pos, int movesToGo[], Square pawnToGo[], EvalInfo& ei) {
+ void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
- Bitboard b2, b3, b4;
- Square ourKingSq = pos.king_square(Us);
- Square theirKingSq = pos.king_square(Them);
- Bitboard b = ei.pi->passed_pawns() & pos.pieces(PAWN, Us);
+ Bitboard squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
+ Bitboard b = ei.pi->passed_pawns() & pos.pieces_of_color(Us);
while (b)
{
assert(pos.pawn_is_passed(Us, s));
int r = int(relative_rank(Us, s) - RANK_2);
- int tr = Max(0, r * (r - 1));
+ int tr = r * (r - 1);
// Base bonus based on rank
Value mbonus = Value(20 * tr);
Value ebonus = Value(10 + r * r * 10);
- // Adjust bonus based on king proximity
if (tr)
{
Square blockSq = s + pawn_push(Us);
- ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr);
- ebonus -= Value(square_distance(ourKingSq, blockSq + pawn_push(Us)) * 1 * tr);
- ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr);
+ // Adjust bonus based on kings proximity
+ ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 3 * tr);
+ ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * 1 * tr);
+ ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 6 * tr);
// If the pawn is free to advance, increase bonus
if (pos.square_is_empty(blockSq))
{
- // There are no enemy pawns in the pawn's path
- b2 = squares_in_front_of(Us, s);
-
- assert((b2 & pos.pieces(PAWN, Them)) == EmptyBoardBB);
+ squaresToQueen = squares_in_front_of(Us, s);
+ defendedSquares = squaresToQueen & ei.attacked_by(Us);
- // Squares attacked by us
- b4 = b2 & ei.attacked_by(Us);
-
- // Squares attacked or occupied by enemy pieces
- b3 = b2 & (ei.attacked_by(Them) | pos.pieces_of_color(Them));
+ // There are no enemy pawns in the pawn's path
+ assert(!(squaresToQueen & pos.pieces(PAWN, Them)));
// If there is an enemy rook or queen attacking the pawn from behind,
- // add all X-ray attacks by the rook or queen.
+ // add all X-ray attacks by the rook or queen. Otherwise consider only
+ // the squares in the pawn's path attacked or occupied by the enemy.
if ( (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them))
&& (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from<QUEEN>(s)))
- b3 = b2;
+ unsafeSquares = squaresToQueen;
+ else
+ unsafeSquares = squaresToQueen & (ei.attacked_by(Them) | pos.pieces_of_color(Them));
- // Are any of the squares in the pawn's path attacked or occupied by the enemy?
- if (b3 == EmptyBoardBB)
- // No enemy attacks or pieces, huge bonus!
- // Even bigger if we protect the pawn's path
- ebonus += Value(tr * (b2 == b4 ? 17 : 15));
+ // If there aren't enemy attacks or pieces along the path to queen give
+ // huge bonus. Even bigger if we protect the pawn's path.
+ if (!unsafeSquares)
+ ebonus += Value(tr * (squaresToQueen == defendedSquares ? 17 : 15));
else
// OK, there are enemy attacks or pieces (but not pawns). Are those
// squares which are attacked by the enemy also attacked by us ?
// If yes, big bonus (but smaller than when there are no enemy attacks),
// if no, somewhat smaller bonus.
- ebonus += Value(tr * ((b3 & b4) == b3 ? 13 : 8));
+ ebonus += Value(tr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8));
// At last, add a small bonus when there are no *friendly* pieces
// in the pawn's path.
- if ((b2 & pos.pieces_of_color(Us)) == EmptyBoardBB)
+ if (!(squaresToQueen & pos.pieces_of_color(Us)))
ebonus += Value(tr);
}
} // tr != 0
- // If the pawn is supported by a friendly pawn, increase bonus
- b2 = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
- if (b2 & rank_bb(s))
+ // Increase the bonus if the passed pawn is supported by a friendly pawn
+ // on the same rank and a bit smaller if it's on the previous rank.
+ supportingPawns = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
+ if (supportingPawns & rank_bb(s))
ebonus += Value(r * 20);
- else if (pos.attacks_from<PAWN>(s, Them) & b2)
+ else if (supportingPawns & rank_bb(s - pawn_push(Us)))
ebonus += Value(r * 12);
- // If the other side has only a king, check whether the pawn is
- // unstoppable
- if (pos.non_pawn_material(Them) == Value(0))
- {
- Square qsq;
- int d;
-
- qsq = relative_square(Us, make_square(square_file(s), RANK_8));
- d = square_distance(s, qsq)
- - square_distance(theirKingSq, qsq)
- + (Us != pos.side_to_move());
-
- if (d < 0)
- {
- int mtg = RANK_8 - relative_rank(Us, s);
- int blockerCount = count_1s_max_15(squares_in_front_of(Us,s) & pos.occupied_squares());
- mtg += blockerCount;
- d += blockerCount;
- if (d < 0 && (!movesToGo[Us] || movesToGo[Us] > mtg))
- {
- movesToGo[Us] = mtg;
- pawnToGo[Us] = s;
- }
- }
- }
-
// Rook pawns are a special case: They are sometimes worse, and
// sometimes better than other passed pawns. It is difficult to find
// good rules for determining whether they are good or bad. For now,
ebonus -= ebonus / 4;
}
- // Add the scores for this pawn to the middle game and endgame eval.
- ei.value += Sign[Us] * apply_weight(make_score(mbonus, ebonus), WeightPassedPawns);
+ // Add the scores for this pawn to the middle game and endgame eval
+ ei.value += Sign[Us] * apply_weight(make_score(mbonus, ebonus), Weights[PassedPawns]);
} // while
}
- // evaluate_passed_pawns() evaluates the passed pawns for both sides
+ // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides
- void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
+ void evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
int movesToGo[2] = {0, 0};
Square pawnToGo[2] = {SQ_NONE, SQ_NONE};
- // Evaluate pawns for each color
- evaluate_passed_pawns_of_color<WHITE>(pos, movesToGo, pawnToGo, ei);
- evaluate_passed_pawns_of_color<BLACK>(pos, movesToGo, pawnToGo, ei);
+ for (Color c = WHITE; c <= BLACK; c++)
+ {
+ // Skip evaluation if other side has non-pawn pieces
+ if (pos.non_pawn_material(opposite_color(c)))
+ continue;
+
+ Bitboard b = ei.pi->passed_pawns() & pos.pieces_of_color(c);
+
+ while (b)
+ {
+ Square s = pop_1st_bit(&b);
+ Square queeningSquare = relative_square(c, make_square(square_file(s), RANK_8));
+ int d = square_distance(s, queeningSquare)
+ - square_distance(pos.king_square(opposite_color(c)), queeningSquare)
+ + int(c != pos.side_to_move());
+
+ if (d < 0)
+ {
+ int mtg = RANK_8 - relative_rank(c, s);
+ int blockerCount = count_1s_max_15(squares_in_front_of(c, s) & pos.occupied_squares());
+ mtg += blockerCount;
+ d += blockerCount;
+ if (d < 0 && (!movesToGo[c] || movesToGo[c] > mtg))
+ {
+ movesToGo[c] = mtg;
+ pawnToGo[c] = s;
+ }
+ }
+ }
+ }
// Neither side has an unstoppable passed pawn?
if (!(movesToGo[WHITE] | movesToGo[BLACK]))
// Find the safe squares for our pieces inside the area defined by
// SpaceMask[us]. A square is unsafe if it is attacked by an enemy
// pawn, or if it is undefended and attacked by an enemy piece.
-
Bitboard safeSquares = SpaceMask[Us]
& ~pos.pieces(PAWN, Us)
& ~ei.attacked_by(Them, PAWN)
- & ~(~ei.attacked_by(Us) & ei.attacked_by(Them));
+ & (ei.attacked_by(Us) | ~ei.attacked_by(Them));
- // Find all squares which are at most three squares behind some friendly
- // pawn.
+ // Find all squares which are at most three squares behind some friendly pawn
Bitboard behindFriendlyPawns = pos.pieces(PAWN, Us);
behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 8 : behindFriendlyPawns << 8);
behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 16 : behindFriendlyPawns << 16);
int space = count_1s_max_15<HasPopCnt>(safeSquares)
+ count_1s_max_15<HasPopCnt>(behindFriendlyPawns & safeSquares);
- ei.value += Sign[Us] * apply_weight(make_score(space * ei.mi->space_weight(), 0), WeightSpace);
+ ei.value += Sign[Us] * apply_weight(make_score(space * ei.mi->space_weight(), 0), Weights[Space]);
}
Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
- Score uciWeight = make_score(get_option_value_int(mgOpt), get_option_value_int(egOpt));
+ // Scale option value from 100 to 256
+ int mg = get_option_value_int(mgOpt) * 256 / 100;
+ int eg = get_option_value_int(egOpt) * 256 / 100;
- // Convert to integer to prevent overflow
- int mg = mg_value(uciWeight);
- int eg = eg_value(uciWeight);
-
- mg = (mg * 0x100) / 100;
- eg = (eg * 0x100) / 100;
- mg = (mg * mg_value(internalWeight)) / 0x100;
- eg = (eg * eg_value(internalWeight)) / 0x100;
- return make_score(mg, eg);
+ return apply_weight(make_score(mg, eg), internalWeight);
}
// init_safety() initizes the king safety evaluation, based on UCI
- // parameters. It is called from read_weights().
+ // parameters. It is called from read_weights().
void init_safety() {
- int maxSlope = 30;
- int peak = 0x500;
- double a = 0.4;
- double b = 0.0;
+ const Value MaxSlope = Value(30);
+ const Value Peak = Value(1280);
+ Value t[100];
+ // First setup the base table
for (int i = 0; i < 100; i++)
{
- if (i < b)
- SafetyTable[i] = Value(0);
- else
- SafetyTable[i] = Value((int)(a * (i - b) * (i - b)));
- }
+ t[i] = Value(int(0.4 * i * i));
- for (int i = 0; i < 100; i++)
- {
- if (SafetyTable[i+1] - SafetyTable[i] > maxSlope)
- for (int j = i + 1; j < 100; j++)
- SafetyTable[j] = SafetyTable[j-1] + Value(maxSlope);
+ if (i > 0)
+ t[i] = Min(t[i], t[i - 1] + MaxSlope);
- if (SafetyTable[i] > Value(peak))
- SafetyTable[i] = Value(peak);
+ t[i] = Min(t[i], Peak);
}
+
+ // Then apply the weights and get the final KingDangerTable[] array
+ for (Color c = WHITE; c <= BLACK; c++)
+ for (int i = 0; i < 100; i++)
+ KingDangerTable[c][i] = apply_weight(make_score(t[i], 0), Weights[KingDangerUs + c]);
}
}
projects / stockfish / blobdiff