Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
- Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, 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
#include "evaluate.h"
#include "material.h"
#include "pawns.h"
-
-std::atomic<Score> Eval::Contempt;
+#include "thread.h"
namespace Trace {
namespace {
- const Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB;
- const Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB;
- const Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB;
- const Bitboard Center = (FileDBB | FileEBB) & (Rank4BB | Rank5BB);
-
- const Bitboard KingFlank[FILE_NB] = {
- QueenSide, QueenSide, QueenSide,
- CenterFiles, CenterFiles,
- KingSide, KingSide, KingSide
- };
-
// Threshold for lazy and space evaluation
- const Value LazyThreshold = Value(1500);
- const Value SpaceThreshold = Value(12222);
+ constexpr Value LazyThreshold = Value(1400);
+ constexpr Value SpaceThreshold = Value(12222);
// KingAttackWeights[PieceType] contains king attack weights by piece type
- const int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 78, 56, 45, 11 };
+ constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 81, 52, 44, 10 };
// Penalties for enemy's safe checks
- const int QueenSafeCheck = 780;
- const int RookSafeCheck = 880;
- const int BishopSafeCheck = 435;
- const int KnightSafeCheck = 790;
+ constexpr int QueenSafeCheck = 772;
+ constexpr int RookSafeCheck = 1084;
+ constexpr int BishopSafeCheck = 645;
+ constexpr int KnightSafeCheck = 792;
#define S(mg, eg) make_score(mg, eg)
// MobilityBonus[PieceType-2][attacked] contains bonuses for middle and end game,
// indexed by piece type and number of attacked squares in the mobility area.
- const Score MobilityBonus[][32] = {
- { S(-75,-76), S(-57,-54), S( -9,-28), S( -2,-10), S( 6, 5), S( 14, 12), // Knights
- S( 22, 26), S( 29, 29), S( 36, 29) },
- { S(-48,-59), S(-20,-23), S( 16, -3), S( 26, 13), S( 38, 24), S( 51, 42), // Bishops
+ constexpr Score MobilityBonus[][32] = {
+ { S(-62,-81), S(-53,-56), S(-12,-30), S( -4,-14), S( 3, 8), S( 13, 15), // Knight
+ S( 22, 23), S( 28, 27), S( 33, 33) },
+ { S(-48,-59), S(-20,-23), S( 16, -3), S( 26, 13), S( 38, 24), S( 51, 42), // Bishop
S( 55, 54), S( 63, 57), S( 63, 65), S( 68, 73), S( 81, 78), S( 81, 86),
S( 91, 88), S( 98, 97) },
- { S(-58,-76), S(-27,-18), S(-15, 28), S(-10, 55), S( -5, 69), S( -2, 82), // Rooks
- S( 9,112), S( 16,118), S( 30,132), S( 29,142), S( 32,155), S( 38,165),
- S( 46,166), S( 48,169), S( 58,171) },
- { S(-39,-36), S(-21,-15), S( 3, 8), S( 3, 18), S( 14, 34), S( 22, 54), // Queens
- S( 28, 61), S( 41, 73), S( 43, 79), S( 48, 92), S( 56, 94), S( 60,104),
- S( 60,113), S( 66,120), S( 67,123), S( 70,126), S( 71,133), S( 73,136),
- S( 79,140), S( 88,143), S( 88,148), S( 99,166), S(102,170), S(102,175),
- S(106,184), S(109,191), S(113,206), S(116,212) }
- };
-
- // Outpost[knight/bishop][supported by pawn] contains bonuses for minor
- // pieces if they occupy or can reach an outpost square, bigger if that
- // square is supported by a pawn.
- const Score Outpost[][2] = {
- { S(22, 6), S(36,12) }, // Knight
- { S( 9, 2), S(15, 5) } // Bishop
+ { S(-60,-78), S(-20,-17), S( 2, 23), S( 3, 39), S( 3, 70), S( 11, 99), // Rook
+ S( 22,103), S( 31,121), S( 40,134), S( 40,139), S( 41,158), S( 48,164),
+ S( 57,168), S( 57,169), S( 62,172) },
+ { S(-34,-36), S(-15,-21), S(-10, -1), S(-10, 22), S( 20, 41), S( 23, 56), // Queen
+ S( 23, 59), S( 35, 75), S( 38, 78), S( 53, 96), S( 64, 96), S( 65,100),
+ S( 65,121), S( 66,127), S( 67,131), S( 67,133), S( 72,136), S( 72,141),
+ S( 77,147), S( 79,150), S( 93,151), S(108,168), S(108,168), S(108,171),
+ S(110,182), S(114,182), S(114,192), S(116,219) }
};
// RookOnFile[semiopen/open] contains bonuses for each rook when there is
// no (friendly) pawn on the rook file.
- const Score RookOnFile[] = { S(20, 7), S(45, 20) };
+ constexpr Score RookOnFile[] = { S(19, 7), S(48, 29) };
// ThreatByMinor/ByRook[attacked PieceType] contains bonuses according to
// which piece type attacks which one. Attacks on lesser pieces which are
// pawn-defended are not considered.
- const Score ThreatByMinor[PIECE_TYPE_NB] = {
- S(0, 0), S(0, 31), S(39, 42), S(57, 44), S(68, 112), S(47, 120)
+ constexpr Score ThreatByMinor[PIECE_TYPE_NB] = {
+ S(0, 0), S(5, 32), S(57, 41), S(77, 56), S(88, 119), S(79, 161)
};
- const Score ThreatByRook[PIECE_TYPE_NB] = {
- S(0, 0), S(0, 24), S(38, 71), S(38, 61), S(0, 38), S(36, 38)
+ constexpr Score ThreatByRook[PIECE_TYPE_NB] = {
+ S(0, 0), S(3, 46), S(37, 68), S(42, 60), S(0, 38), S(58, 41)
};
- // ThreatByKing[on one/on many] contains bonuses for king attacks on
- // pawns or pieces which are not pawn-defended.
- const Score ThreatByKing[] = { S(3, 65), S(9, 145) };
-
// PassedRank[Rank] contains a bonus according to the rank of a passed pawn
- const Score PassedRank[RANK_NB] = {
- S(0, 0), S(5, 7), S(5, 13), S(32, 42), S(70, 70), S(172, 170), S(217, 269)
- };
-
- // PassedFile[File] contains a bonus according to the file of a passed pawn
- const Score PassedFile[FILE_NB] = {
- S( 9, 10), S(2, 10), S(1, -8), S(-20,-12),
- S(-20,-12), S(1, -8), S(2, 10), S( 9, 10)
+ constexpr Score PassedRank[RANK_NB] = {
+ S(0, 0), S(10, 28), S(17, 33), S(15, 41), S(62, 72), S(168, 177), S(276, 260)
};
- // PassedDanger[Rank] contains a term to weight the passed score
- const int PassedDanger[RANK_NB] = { 0, 0, 0, 2, 7, 12, 19 };
-
- // KingProtector[PieceType-2] contains a penalty according to distance from king
- const Score KingProtector[] = { S(3, 5), S(4, 3), S(3, 0), S(1, -1) };
-
// Assorted bonuses and penalties
- const Score BishopPawns = S( 8, 12);
- const Score CloseEnemies = S( 7, 0);
- const Score Hanging = S( 52, 30);
- const Score HinderPassedPawn = S( 8, 1);
- const Score LongRangedBishop = S( 22, 0);
- const Score MinorBehindPawn = S( 16, 0);
- const Score PawnlessFlank = S( 20, 80);
- const Score RookOnPawn = S( 8, 24);
- const Score ThreatByPawnPush = S( 47, 26);
- const Score ThreatByRank = S( 16, 3);
- const Score ThreatBySafePawn = S(175,168);
- const Score ThreatOnQueen = S( 42, 21);
- const Score TrappedBishopA1H1 = S( 50, 50);
- const Score TrappedRook = S( 92, 0);
- const Score WeakQueen = S( 50, 10);
- const Score WeakUnopposedPawn = S( 5, 25);
+ constexpr Score BishopPawns = S( 3, 7);
+ constexpr Score BishopXRayPawns = S( 4, 5);
+ constexpr Score CorneredBishop = S( 50, 50);
+ constexpr Score FlankAttacks = S( 8, 0);
+ constexpr Score Hanging = S( 69, 36);
+ constexpr Score BishopKingProtector = S( 6, 9);
+ constexpr Score KnightKingProtector = S( 8, 9);
+ constexpr Score KnightOnQueen = S( 16, 11);
+ constexpr Score LongDiagonalBishop = S( 45, 0);
+ constexpr Score MinorBehindPawn = S( 18, 3);
+ constexpr Score KnightOutpost = S( 56, 36);
+ constexpr Score BishopOutpost = S( 30, 23);
+ constexpr Score ReachableOutpost = S( 31, 22);
+ constexpr Score PassedFile = S( 11, 8);
+ constexpr Score PawnlessFlank = S( 17, 95);
+ constexpr Score RestrictedPiece = S( 7, 7);
+ constexpr Score RookOnQueenFile = S( 5, 9);
+ constexpr Score SliderOnQueen = S( 59, 18);
+ constexpr Score ThreatByKing = S( 24, 89);
+ constexpr Score ThreatByPawnPush = S( 48, 39);
+ constexpr Score ThreatBySafePawn = S(173, 94);
+ constexpr Score TrappedRook = S( 55, 13);
+ constexpr Score WeakQueen = S( 51, 14);
+ constexpr Score WeakQueenProtection = S( 15, 0);
#undef S
template<Color Us> Score passed() const;
template<Color Us> Score space() const;
ScaleFactor scale_factor(Value eg) const;
- Score initiative(Value eg) const;
+ Score initiative(Score score) const;
const Position& pos;
Material::Entry* me;
// attackedBy[color][piece type] is a bitboard representing all squares
// attacked by a given color and piece type. Special "piece types" which
- // are also calculated are QUEEN_DIAGONAL and ALL_PIECES.
+ // is also calculated is ALL_PIECES.
Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB];
- // attackedBy2[color] are the squares attacked by 2 pieces of a given color,
- // possibly via x-ray or by one pawn and one piece. Diagonal x-ray through
- // pawn or squares attacked by 2 pawns are not explicitly added.
+ // attackedBy2[color] are the squares attacked by at least 2 units of a given
+ // color, including x-rays. But diagonal x-rays through pawns are not computed.
Bitboard attackedBy2[COLOR_NB];
- // kingRing[color] are the squares adjacent to the king, plus (only for a
- // king on its first rank) the squares two ranks in front. For instance,
- // if black's king is on g8, kingRing[BLACK] is f8, h8, f7, g7, h7, f6, g6
- // and h6. It is set to 0 when king safety evaluation is skipped.
+ // kingRing[color] are the squares adjacent to the king plus some other
+ // very near squares, depending on king position.
Bitboard kingRing[COLOR_NB];
// kingAttackersCount[color] is the number of pieces of the given color
// which attack a square in the kingRing of the enemy king.
int kingAttackersCount[COLOR_NB];
- // kingAttackersWeight[color] is the sum of the "weights" of the pieces of the
- // given color which attack a square in the kingRing of the enemy king. The
- // weights of the individual piece types are given by the elements in the
- // KingAttackWeights array.
+ // kingAttackersWeight[color] is the sum of the "weights" of the pieces of
+ // the given color which attack a square in the kingRing of the enemy king.
+ // The weights of the individual piece types are given by the elements in
+ // the KingAttackWeights array.
int kingAttackersWeight[COLOR_NB];
- // 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
+ // kingAttacksCount[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];
+ // to kingAttacksCount[WHITE].
+ int kingAttacksCount[COLOR_NB];
};
template<Tracing T> template<Color Us>
void Evaluation<T>::initialize() {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Direction Up = (Us == WHITE ? NORTH : SOUTH);
- const Direction Down = (Us == WHITE ? SOUTH : NORTH);
- const Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB: Rank7BB | Rank6BB);
+ constexpr Color Them = ~Us;
+ constexpr Direction Up = pawn_push(Us);
+ constexpr Direction Down = -Up;
+ constexpr Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB : Rank7BB | Rank6BB);
+
+ const Square ksq = pos.square<KING>(Us);
+
+ Bitboard dblAttackByPawn = pawn_double_attacks_bb<Us>(pos.pieces(Us, PAWN));
// Find our pawns that are blocked or on the first two ranks
Bitboard b = pos.pieces(Us, PAWN) & (shift<Down>(pos.pieces()) | LowRanks);
- // Squares occupied by those pawns, by our king, or controlled by enemy pawns
- // are excluded from the mobility area.
- mobilityArea[Us] = ~(b | pos.square<KING>(Us) | pe->pawn_attacks(Them));
+ // Squares occupied by those pawns, by our king or queen, by blockers to attacks on our king
+ // or controlled by enemy pawns are excluded from the mobility area.
+ mobilityArea[Us] = ~(b | pos.pieces(Us, KING, QUEEN) | pos.blockers_for_king(Us) | pe->pawn_attacks(Them));
- // Initialise attackedBy bitboards for kings and pawns
- attackedBy[Us][KING] = pos.attacks_from<KING>(pos.square<KING>(Us));
+ // Initialize attackedBy[] for king and pawns
+ attackedBy[Us][KING] = pos.attacks_from<KING>(ksq);
attackedBy[Us][PAWN] = pe->pawn_attacks(Us);
attackedBy[Us][ALL_PIECES] = attackedBy[Us][KING] | attackedBy[Us][PAWN];
- attackedBy2[Us] = attackedBy[Us][KING] & attackedBy[Us][PAWN];
+ attackedBy2[Us] = dblAttackByPawn | (attackedBy[Us][KING] & attackedBy[Us][PAWN]);
- // Init our king safety tables only if we are going to use them
- if (pos.non_pawn_material(Them) >= RookValueMg + KnightValueMg)
- {
- kingRing[Us] = attackedBy[Us][KING];
- if (relative_rank(Us, pos.square<KING>(Us)) == RANK_1)
- kingRing[Us] |= shift<Up>(kingRing[Us]);
+ // Init our king safety tables
+ Square s = make_square(Utility::clamp(file_of(ksq), FILE_B, FILE_G),
+ Utility::clamp(rank_of(ksq), RANK_2, RANK_7));
+ kingRing[Us] = PseudoAttacks[KING][s] | s;
- kingAttackersCount[Them] = popcount(attackedBy[Us][KING] & pe->pawn_attacks(Them));
- kingAdjacentZoneAttacksCount[Them] = kingAttackersWeight[Them] = 0;
- }
- else
- kingRing[Us] = kingAttackersCount[Them] = 0;
+ kingAttackersCount[Them] = popcount(kingRing[Us] & pe->pawn_attacks(Them));
+ kingAttacksCount[Them] = kingAttackersWeight[Them] = 0;
+
+ // Remove from kingRing[] the squares defended by two pawns
+ kingRing[Us] &= ~dblAttackByPawn;
}
template<Tracing T> template<Color Us, PieceType Pt>
Score Evaluation<T>::pieces() {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB
- : Rank5BB | Rank4BB | Rank3BB);
+ constexpr Color Them = ~Us;
+ constexpr Direction Down = -pawn_push(Us);
+ constexpr Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB
+ : Rank5BB | Rank4BB | Rank3BB);
const Square* pl = pos.squares<Pt>(Us);
Bitboard b, bb;
- Square s;
Score score = SCORE_ZERO;
attackedBy[Us][Pt] = 0;
- if (Pt == QUEEN)
- attackedBy[Us][QUEEN_DIAGONAL] = 0;
-
- while ((s = *pl++) != SQ_NONE)
+ for (Square s = *pl; s != SQ_NONE; s = *++pl)
{
// Find attacked squares, including x-ray attacks for bishops and rooks
b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(QUEEN))
attackedBy[Us][Pt] |= b;
attackedBy[Us][ALL_PIECES] |= b;
- if (Pt == QUEEN)
- attackedBy[Us][QUEEN_DIAGONAL] |= b & PseudoAttacks[BISHOP][s];
-
if (b & kingRing[Them])
{
kingAttackersCount[Us]++;
kingAttackersWeight[Us] += KingAttackWeights[Pt];
- kingAdjacentZoneAttacksCount[Us] += popcount(b & attackedBy[Them][KING]);
+ kingAttacksCount[Us] += popcount(b & attackedBy[Them][KING]);
}
int mob = popcount(b & mobilityArea[Us]);
mobility[Us] += MobilityBonus[Pt - 2][mob];
- // Penalty if the piece is far from the king
- score -= KingProtector[Pt - 2] * distance(s, pos.square<KING>(Us));
-
if (Pt == BISHOP || Pt == KNIGHT)
{
// Bonus if piece is on an outpost square or can reach one
- bb = OutpostRanks & ~pe->pawn_attacks_span(Them);
+ bb = OutpostRanks & attackedBy[Us][PAWN] & ~pe->pawn_attacks_span(Them);
if (bb & s)
- score += Outpost[Pt == BISHOP][bool(attackedBy[Us][PAWN] & s)] * 2;
-
- else if (bb &= b & ~pos.pieces(Us))
- score += Outpost[Pt == BISHOP][bool(attackedBy[Us][PAWN] & bb)];
+ score += (Pt == KNIGHT) ? KnightOutpost : BishopOutpost;
+ else if (Pt == KNIGHT && bb & b & ~pos.pieces(Us))
+ score += ReachableOutpost;
- // Bonus when behind a pawn
- if ( relative_rank(Us, s) < RANK_5
- && (pos.pieces(PAWN) & (s + pawn_push(Us))))
+ // Bonus for a knight or bishop shielded by pawn
+ if (shift<Down>(pos.pieces(PAWN)) & s)
score += MinorBehindPawn;
+ // Penalty if the piece is far from the king
+ score -= (Pt == KNIGHT ? KnightKingProtector
+ : BishopKingProtector) * distance(pos.square<KING>(Us), s);
+
if (Pt == BISHOP)
{
- // Penalty according to number of pawns on the same color square as the bishop
- score -= BishopPawns * pe->pawns_on_same_color_squares(Us, s);
+ // Penalty according to number of pawns on the same color square as the
+ // bishop, bigger when the center files are blocked with pawns and smaller
+ // when the bishop is outside the pawn chain.
+ Bitboard blocked = pos.pieces(Us, PAWN) & shift<Down>(pos.pieces());
- // Bonus for bishop on a long diagonal which can "see" both center squares
- if (more_than_one(Center & (attacks_bb<BISHOP>(s, pos.pieces(PAWN)) | s)))
- score += LongRangedBishop;
- }
+ score -= BishopPawns * pos.pawns_on_same_color_squares(Us, s)
+ * (!(attackedBy[Us][PAWN] & s) + popcount(blocked & CenterFiles));
- // An important Chess960 pattern: A cornered bishop blocked by a friendly
- // pawn diagonally in front of it is a very serious problem, especially
- // when that pawn is also blocked.
- if ( Pt == BISHOP
- && pos.is_chess960()
- && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
- {
- Direction d = pawn_push(Us) + (file_of(s) == FILE_A ? EAST : WEST);
- if (pos.piece_on(s + d) == make_piece(Us, PAWN))
- score -= !pos.empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4
- : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? TrappedBishopA1H1 * 2
- : TrappedBishopA1H1;
+ // Penalty for all enemy pawns x-rayed
+ score -= BishopXRayPawns * popcount(PseudoAttacks[BISHOP][s] & pos.pieces(Them, PAWN));
+
+ // Bonus for bishop on a long diagonal which can "see" both center squares
+ if (more_than_one(attacks_bb<BISHOP>(s, pos.pieces(PAWN)) & Center))
+ score += LongDiagonalBishop;
+
+ // An important Chess960 pattern: a cornered bishop blocked by a friendly
+ // pawn diagonally in front of it is a very serious problem, especially
+ // when that pawn is also blocked.
+ if ( pos.is_chess960()
+ && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
+ {
+ Direction d = pawn_push(Us) + (file_of(s) == FILE_A ? EAST : WEST);
+ if (pos.piece_on(s + d) == make_piece(Us, PAWN))
+ score -= !pos.empty(s + d + pawn_push(Us)) ? CorneredBishop * 4
+ : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? CorneredBishop * 2
+ : CorneredBishop;
+ }
}
}
if (Pt == ROOK)
{
- // Bonus for aligning rook with with enemy pawns on the same rank/file
- if (relative_rank(Us, s) >= RANK_5)
- score += RookOnPawn * popcount(pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]);
+ // Bonus for rook on the same file as a queen
+ if (file_bb(s) & pos.pieces(QUEEN))
+ score += RookOnQueenFile;
// Bonus for rook on an open or semi-open file
- if (pe->semiopen_file(Us, file_of(s)))
- score += RookOnFile[bool(pe->semiopen_file(Them, file_of(s)))];
+ if (pos.is_on_semiopen_file(Us, s))
+ score += RookOnFile[pos.is_on_semiopen_file(Them, s)];
// Penalty when trapped by the king, even more if the king cannot castle
else if (mob <= 3)
{
File kf = file_of(pos.square<KING>(Us));
if ((kf < FILE_E) == (file_of(s) < kf))
- score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us));
+ score -= TrappedRook * (1 + !pos.castling_rights(Us));
}
}
template<Tracing T> template<Color Us>
Score Evaluation<T>::king() const {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Bitboard Camp = (Us == WHITE ? AllSquares ^ Rank6BB ^ Rank7BB ^ Rank8BB
- : AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB);
+ constexpr Color Them = ~Us;
+ constexpr Bitboard Camp = (Us == WHITE ? AllSquares ^ Rank6BB ^ Rank7BB ^ Rank8BB
+ : AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB);
+ Bitboard weak, b1, b2, b3, safe, unsafeChecks = 0;
+ Bitboard rookChecks, queenChecks, bishopChecks, knightChecks;
+ int kingDanger = 0;
const Square ksq = pos.square<KING>(Us);
- Bitboard weak, b, b1, b2, safe, unsafeChecks, pinned;
-
- // King shelter and enemy pawns storm
- Score score = pe->king_safety<Us>(pos, ksq);
-
- // Main king safety evaluation
- if (kingAttackersCount[Them] > 1 - pos.count<QUEEN>(Them))
- {
- int kingDanger = unsafeChecks = 0;
- // Attacked squares defended at most once by our queen or king
- weak = attackedBy[Them][ALL_PIECES]
- & ~attackedBy2[Us]
- & (~attackedBy[Us][ALL_PIECES] | attackedBy[Us][KING] | attackedBy[Us][QUEEN]);
+ // Init the score with king shelter and enemy pawns storm
+ Score score = pe->king_safety<Us>(pos);
- // Analyse the safe enemy's checks which are possible on next move
- safe = ~pos.pieces(Them);
- safe &= ~attackedBy[Us][ALL_PIECES] | (weak & attackedBy2[Them]);
+ // Attacked squares defended at most once by our queen or king
+ weak = attackedBy[Them][ALL_PIECES]
+ & ~attackedBy2[Us]
+ & (~attackedBy[Us][ALL_PIECES] | attackedBy[Us][KING] | attackedBy[Us][QUEEN]);
- b1 = attacks_bb<ROOK >(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN));
- b2 = attacks_bb<BISHOP>(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN));
+ // Analyse the safe enemy's checks which are possible on next move
+ safe = ~pos.pieces(Them);
+ safe &= ~attackedBy[Us][ALL_PIECES] | (weak & attackedBy2[Them]);
- // Enemy queen safe checks
- if ((b1 | b2) & attackedBy[Them][QUEEN] & safe & ~attackedBy[Us][QUEEN])
- kingDanger += QueenSafeCheck;
+ b1 = attacks_bb<ROOK >(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN));
+ b2 = attacks_bb<BISHOP>(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN));
- b1 &= attackedBy[Them][ROOK];
- b2 &= attackedBy[Them][BISHOP];
-
- // Enemy rooks checks
- if (b1 & safe)
- kingDanger += RookSafeCheck;
- else
- unsafeChecks |= b1;
+ // Enemy rooks checks
+ rookChecks = b1 & safe & attackedBy[Them][ROOK];
+ if (rookChecks)
+ kingDanger += more_than_one(rookChecks) ? RookSafeCheck * 175/100
+ : RookSafeCheck;
+ else
+ unsafeChecks |= b1 & attackedBy[Them][ROOK];
+
+ // Enemy queen safe checks: we count them only if they are from squares from
+ // which we can't give a rook check, because rook checks are more valuable.
+ queenChecks = (b1 | b2)
+ & attackedBy[Them][QUEEN]
+ & safe
+ & ~attackedBy[Us][QUEEN]
+ & ~rookChecks;
+ if (queenChecks)
+ kingDanger += more_than_one(queenChecks) ? QueenSafeCheck * 145/100
+ : QueenSafeCheck;
+
+ // Enemy bishops checks: we count them only if they are from squares from
+ // which we can't give a queen check, because queen checks are more valuable.
+ bishopChecks = b2
+ & attackedBy[Them][BISHOP]
+ & safe
+ & ~queenChecks;
+ if (bishopChecks)
+ kingDanger += more_than_one(bishopChecks) ? BishopSafeCheck * 3/2
+ : BishopSafeCheck;
+ else
+ unsafeChecks |= b2 & attackedBy[Them][BISHOP];
- // Enemy bishops checks
- if (b2 & safe)
- kingDanger += BishopSafeCheck;
- else
- unsafeChecks |= b2;
+ // Enemy knights checks
+ knightChecks = pos.attacks_from<KNIGHT>(ksq) & attackedBy[Them][KNIGHT];
+ if (knightChecks & safe)
+ kingDanger += more_than_one(knightChecks & safe) ? KnightSafeCheck * 162/100
+ : KnightSafeCheck;
+ else
+ unsafeChecks |= knightChecks;
+
+ // Find the squares that opponent attacks in our king flank, the squares
+ // which they attack twice in that flank, and the squares that we defend.
+ b1 = attackedBy[Them][ALL_PIECES] & KingFlank[file_of(ksq)] & Camp;
+ b2 = b1 & attackedBy2[Them];
+ b3 = attackedBy[Us][ALL_PIECES] & KingFlank[file_of(ksq)] & Camp;
+
+ int kingFlankAttack = popcount(b1) + popcount(b2);
+ int kingFlankDefense = popcount(b3);
+
+ kingDanger += kingAttackersCount[Them] * kingAttackersWeight[Them]
+ + 185 * popcount(kingRing[Us] & weak)
+ + 148 * popcount(unsafeChecks)
+ + 98 * popcount(pos.blockers_for_king(Us))
+ + 69 * kingAttacksCount[Them]
+ + 3 * kingFlankAttack * kingFlankAttack / 8
+ + mg_value(mobility[Them] - mobility[Us])
+ - 873 * !pos.count<QUEEN>(Them)
+ - 100 * bool(attackedBy[Us][KNIGHT] & attackedBy[Us][KING])
+ - 6 * mg_value(score) / 8
+ - 4 * kingFlankDefense
+ + 37;
+
+ // Transform the kingDanger units into a Score, and subtract it from the evaluation
+ if (kingDanger > 100)
+ score -= make_score(kingDanger * kingDanger / 4096, kingDanger / 16);
- // Enemy knights checks
- b = pos.attacks_from<KNIGHT>(ksq) & attackedBy[Them][KNIGHT];
- if (b & safe)
- kingDanger += KnightSafeCheck;
- else
- unsafeChecks |= b;
-
- // Unsafe or occupied checking squares will also be considered, as long as
- // the square is in the attacker's mobility area.
- unsafeChecks &= mobilityArea[Them];
- pinned = pos.blockers_for_king(Us) & pos.pieces(Us);
-
- kingDanger += kingAttackersCount[Them] * kingAttackersWeight[Them]
- + 102 * kingAdjacentZoneAttacksCount[Them]
- + 191 * popcount(kingRing[Us] & weak)
- + 143 * popcount(pinned | unsafeChecks)
- - 848 * !pos.count<QUEEN>(Them)
- - 9 * mg_value(score) / 8
- + 40;
-
- // Transform the kingDanger units into a Score, and subtract it from the evaluation
- if (kingDanger > 0)
- {
- int mobilityDanger = mg_value(mobility[Them] - mobility[Us]);
- kingDanger = std::max(0, kingDanger + mobilityDanger);
- score -= make_score(kingDanger * kingDanger / 4096, kingDanger / 16);
- }
- }
// Penalty when our king is on a pawnless flank
if (!(pos.pieces(PAWN) & KingFlank[file_of(ksq)]))
score -= PawnlessFlank;
- // King tropism: firstly, find attacked squares in our king flank
- b = attackedBy[Them][ALL_PIECES] & KingFlank[file_of(ksq)] & Camp;
-
- assert(((Us == WHITE ? b << 4 : b >> 4) & b) == 0);
- assert(popcount(Us == WHITE ? b << 4 : b >> 4) == popcount(b));
-
- // Secondly, add the squares which are attacked twice in that flank and
- // which are not defended by our pawns.
- b = (Us == WHITE ? b << 4 : b >> 4)
- | (b & attackedBy2[Them] & ~attackedBy[Us][PAWN]);
-
- score -= CloseEnemies * popcount(b);
+ // Penalty if king flank is under attack, potentially moving toward the king
+ score -= FlankAttacks * kingFlankAttack;
if (T)
Trace::add(KING, Us, score);
template<Tracing T> template<Color Us>
Score Evaluation<T>::threats() const {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Direction Up = (Us == WHITE ? NORTH : SOUTH);
- const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
+ constexpr Color Them = ~Us;
+ constexpr Direction Up = pawn_push(Us);
+ constexpr Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
- Bitboard b, weak, defended, nonPawnEnemies, stronglyProtected, safeThreats;
+ Bitboard b, weak, defended, nonPawnEnemies, stronglyProtected, safe;
Score score = SCORE_ZERO;
- // Non-pawn enemies attacked by a pawn
- nonPawnEnemies = pos.pieces(Them) ^ pos.pieces(Them, PAWN);
- weak = nonPawnEnemies & attackedBy[Us][PAWN];
-
- if (weak)
- {
- // Our safe or protected pawns
- b = pos.pieces(Us, PAWN)
- & (~attackedBy[Them][ALL_PIECES] | attackedBy[Us][ALL_PIECES]);
-
- safeThreats = pawn_attacks_bb<Us>(b) & weak;
- score += ThreatBySafePawn * popcount(safeThreats);
- }
+ // Non-pawn enemies
+ nonPawnEnemies = pos.pieces(Them) & ~pos.pieces(PAWN);
// Squares strongly protected by the enemy, either because they defend the
// square with a pawn, or because they defend the square twice and we don't.
{
b = (defended | weak) & (attackedBy[Us][KNIGHT] | attackedBy[Us][BISHOP]);
while (b)
- {
- Square s = pop_lsb(&b);
- score += ThreatByMinor[type_of(pos.piece_on(s))];
- if (type_of(pos.piece_on(s)) != PAWN)
- score += ThreatByRank * (int)relative_rank(Them, s);
- }
+ score += ThreatByMinor[type_of(pos.piece_on(pop_lsb(&b)))];
- b = (pos.pieces(Them, QUEEN) | weak) & attackedBy[Us][ROOK];
+ b = weak & attackedBy[Us][ROOK];
while (b)
- {
- Square s = pop_lsb(&b);
- score += ThreatByRook[type_of(pos.piece_on(s))];
- if (type_of(pos.piece_on(s)) != PAWN)
- score += ThreatByRank * (int)relative_rank(Them, s);
- }
+ score += ThreatByRook[type_of(pos.piece_on(pop_lsb(&b)))];
- score += Hanging * popcount(weak & ~attackedBy[Them][ALL_PIECES]);
+ if (weak & attackedBy[Us][KING])
+ score += ThreatByKing;
- b = weak & attackedBy[Us][KING];
- if (b)
- score += ThreatByKing[more_than_one(b)];
+ b = ~attackedBy[Them][ALL_PIECES]
+ | (nonPawnEnemies & attackedBy2[Us]);
+ score += Hanging * popcount(weak & b);
+
+ // Additional bonus if weak piece is only protected by a queen
+ score += WeakQueenProtection * popcount(weak & attackedBy[Them][QUEEN]);
}
- // Bonus for enemy unopposed weak pawns
- if (pos.pieces(Us, ROOK, QUEEN))
- score += WeakUnopposedPawn * pe->weak_unopposed(Them);
+ // Bonus for restricting their piece moves
+ b = attackedBy[Them][ALL_PIECES]
+ & ~stronglyProtected
+ & attackedBy[Us][ALL_PIECES];
+ score += RestrictedPiece * popcount(b);
+
+ // Protected or unattacked squares
+ safe = ~attackedBy[Them][ALL_PIECES] | attackedBy[Us][ALL_PIECES];
+
+ // Bonus for attacking enemy pieces with our relatively safe pawns
+ b = pos.pieces(Us, PAWN) & safe;
+ b = pawn_attacks_bb<Us>(b) & nonPawnEnemies;
+ score += ThreatBySafePawn * popcount(b);
// Find squares where our pawns can push on the next move
b = shift<Up>(pos.pieces(Us, PAWN)) & ~pos.pieces();
b |= shift<Up>(b & TRank3BB) & ~pos.pieces();
- // Keep only the squares which are not completely unsafe
- b &= ~attackedBy[Them][PAWN]
- & (attackedBy[Us][ALL_PIECES] | ~attackedBy[Them][ALL_PIECES]);
+ // Keep only the squares which are relatively safe
+ b &= ~attackedBy[Them][PAWN] & safe;
// Bonus for safe pawn threats on the next move
- b = pawn_attacks_bb<Us>(b)
- & pos.pieces(Them)
- & ~attackedBy[Us][PAWN];
-
+ b = pawn_attacks_bb<Us>(b) & nonPawnEnemies;
score += ThreatByPawnPush * popcount(b);
- // Bonus for safe slider threats on the next move toward enemy queen
- safeThreats = ~pos.pieces(Us) & ~attackedBy2[Them] & attackedBy2[Us];
- b = (attackedBy[Us][BISHOP] & attackedBy[Them][QUEEN_DIAGONAL])
- | (attackedBy[Us][ROOK ] & attackedBy[Them][QUEEN] & ~attackedBy[Them][QUEEN_DIAGONAL]);
+ // Bonus for threats on the next moves against enemy queen
+ if (pos.count<QUEEN>(Them) == 1)
+ {
+ Square s = pos.square<QUEEN>(Them);
+ safe = mobilityArea[Us] & ~stronglyProtected;
+
+ b = attackedBy[Us][KNIGHT] & pos.attacks_from<KNIGHT>(s);
+
+ score += KnightOnQueen * popcount(b & safe);
- score += ThreatOnQueen * popcount(b & safeThreats);
+ b = (attackedBy[Us][BISHOP] & pos.attacks_from<BISHOP>(s))
+ | (attackedBy[Us][ROOK ] & pos.attacks_from<ROOK >(s));
+
+ score += SliderOnQueen * popcount(b & safe & attackedBy2[Us]);
+ }
if (T)
Trace::add(THREAT, Us, score);
template<Tracing T> template<Color Us>
Score Evaluation<T>::passed() const {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Direction Up = (Us == WHITE ? NORTH : SOUTH);
+ constexpr Color Them = ~Us;
+ constexpr Direction Up = pawn_push(Us);
+ constexpr Direction Down = -Up;
auto king_proximity = [&](Color c, Square s) {
return std::min(distance(pos.square<KING>(c), s), 5);
};
- Bitboard b, bb, squaresToQueen, defendedSquares, unsafeSquares;
+ Bitboard b, bb, squaresToQueen, unsafeSquares, blockedPassers, helpers;
Score score = SCORE_ZERO;
b = pe->passed_pawns(Us);
+ blockedPassers = b & shift<Down>(pos.pieces(Them, PAWN));
+ if (blockedPassers)
+ {
+ helpers = shift<Up>(pos.pieces(Us, PAWN))
+ & ~pos.pieces(Them)
+ & (~attackedBy2[Them] | attackedBy[Us][ALL_PIECES]);
+
+ // Remove blocked candidate passers that don't have help to pass
+ b &= ~blockedPassers
+ | shift<WEST>(helpers)
+ | shift<EAST>(helpers);
+ }
+
while (b)
{
Square s = pop_lsb(&b);
assert(!(pos.pieces(Them, PAWN) & forward_file_bb(Us, s + Up)));
- bb = forward_file_bb(Us, s) & (attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
- score -= HinderPassedPawn * popcount(bb);
-
int r = relative_rank(Us, s);
- int w = PassedDanger[r];
Score bonus = PassedRank[r];
- if (w)
+ if (r > RANK_3)
{
+ int w = 5 * r - 13;
Square blockSq = s + Up;
// Adjust bonus based on the king's proximity
- bonus += make_score(0, ( king_proximity(Them, blockSq) * 5
- - king_proximity(Us, blockSq) * 2) * w);
+ bonus += make_score(0, ( (king_proximity(Them, blockSq) * 19) / 4
+ - king_proximity(Us, blockSq) * 2) * w);
// If blockSq is not the queening square then consider also a second push
if (r != RANK_7)
// If the pawn is free to advance, then increase the bonus
if (pos.empty(blockSq))
{
- // If there is a rook or queen attacking/defending the pawn from behind,
- // consider all the squaresToQueen. Otherwise consider only the squares
- // in the pawn's path attacked or occupied by the enemy.
- defendedSquares = unsafeSquares = squaresToQueen = forward_file_bb(Us, s);
+ squaresToQueen = forward_file_bb(Us, s);
+ unsafeSquares = passed_pawn_span(Us, s);
- bb = forward_file_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from<ROOK>(s);
-
- if (!(pos.pieces(Us) & bb))
- defendedSquares &= attackedBy[Us][ALL_PIECES];
+ bb = forward_file_bb(Them, s) & pos.pieces(ROOK, QUEEN);
if (!(pos.pieces(Them) & bb))
- unsafeSquares &= attackedBy[Them][ALL_PIECES] | pos.pieces(Them);
-
- // If there aren't any enemy attacks, assign a big bonus. Otherwise
- // assign a smaller bonus if the block square isn't attacked.
- int k = !unsafeSquares ? 20 : !(unsafeSquares & blockSq) ? 9 : 0;
+ unsafeSquares &= attackedBy[Them][ALL_PIECES];
- // If the path to the queen is fully defended, assign a big bonus.
- // Otherwise assign a smaller bonus if the block square is defended.
- if (defendedSquares == squaresToQueen)
- k += 6;
+ // If there are no enemy attacks on passed pawn span, assign a big bonus.
+ // Otherwise assign a smaller bonus if the path to queen is not attacked
+ // and even smaller bonus if it is attacked but block square is not.
+ int k = !unsafeSquares ? 35 :
+ !(unsafeSquares & squaresToQueen) ? 20 :
+ !(unsafeSquares & blockSq) ? 9 :
+ 0 ;
- else if (defendedSquares & blockSq)
- k += 4;
+ // Assign a larger bonus if the block square is defended
+ if ((pos.pieces(Us) & bb) || (attackedBy[Us][ALL_PIECES] & blockSq))
+ k += 5;
bonus += make_score(k * w, k * w);
}
- else if (pos.pieces(Us) & blockSq)
- bonus += make_score(w + r * 2, w + r * 2);
- } // rr != 0
+ } // r > RANK_3
- // Scale down bonus for candidate passers which need more than one
- // pawn push to become passed or have a pawn in front of them.
- if ( !pos.pawn_passed(Us, s + Up)
- || (pos.pieces(PAWN) & forward_file_bb(Us, s)))
- bonus = bonus / 2;
-
- score += bonus + PassedFile[file_of(s)];
+ score += bonus - PassedFile * edge_distance(file_of(s));
}
if (T)
template<Tracing T> template<Color Us>
Score Evaluation<T>::space() const {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Bitboard SpaceMask =
- Us == WHITE ? CenterFiles & (Rank2BB | Rank3BB | Rank4BB)
- : CenterFiles & (Rank7BB | Rank6BB | Rank5BB);
-
if (pos.non_pawn_material() < SpaceThreshold)
return SCORE_ZERO;
- // Find the safe squares for our pieces inside the area defined by
- // SpaceMask. A square is unsafe if it is attacked by an enemy
- // pawn, or if it is undefended and attacked by an enemy piece.
+ constexpr Color Them = ~Us;
+ constexpr Direction Down = -pawn_push(Us);
+ constexpr Bitboard SpaceMask =
+ Us == WHITE ? CenterFiles & (Rank2BB | Rank3BB | Rank4BB)
+ : CenterFiles & (Rank7BB | Rank6BB | Rank5BB);
+
+ // Find the available squares for our pieces inside the area defined by SpaceMask
Bitboard safe = SpaceMask
& ~pos.pieces(Us, PAWN)
- & ~attackedBy[Them][PAWN]
- & (attackedBy[Us][ALL_PIECES] | ~attackedBy[Them][ALL_PIECES]);
+ & ~attackedBy[Them][PAWN];
// Find all squares which are at most three squares behind some friendly pawn
Bitboard behind = pos.pieces(Us, PAWN);
- behind |= (Us == WHITE ? behind >> 8 : behind << 8);
- behind |= (Us == WHITE ? behind >> 16 : behind << 16);
-
- // Since SpaceMask[Us] is fully on our half of the board...
- assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);
+ behind |= shift<Down>(behind);
+ behind |= shift<Down+Down>(behind);
- // ...count safe + (behind & safe) with a single popcount.
- int bonus = popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
- int weight = pos.count<ALL_PIECES>(Us) - 2 * pe->open_files();
+ int bonus = popcount(safe) + popcount(behind & safe & ~attackedBy[Them][ALL_PIECES]);
+ int weight = pos.count<ALL_PIECES>(Us) - 3 + std::min(pe->blocked_count(), 9);
Score score = make_score(bonus * weight * weight / 16, 0);
if (T)
// known attacking/defending status of the players.
template<Tracing T>
- Score Evaluation<T>::initiative(Value eg) const {
+ Score Evaluation<T>::initiative(Score score) const {
int outflanking = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
- distance<Rank>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
bool pawnsOnBothFlanks = (pos.pieces(PAWN) & QueenSide)
&& (pos.pieces(PAWN) & KingSide);
+ bool almostUnwinnable = outflanking < 0
+ && !pawnsOnBothFlanks;
+
+ bool infiltration = rank_of(pos.square<KING>(WHITE)) > RANK_4
+ || rank_of(pos.square<KING>(BLACK)) < RANK_5;
+
// Compute the initiative bonus for the attacking side
- int complexity = 8 * outflanking
- + 8 * pe->pawn_asymmetry()
- + 12 * pos.count<PAWN>()
- + 16 * pawnsOnBothFlanks
- -136 ;
-
- // Now apply the bonus: note that we find the attacking side by extracting
- // the sign of the endgame value, and that we carefully cap the bonus so
- // that the endgame score will never change sign after the bonus.
+ int complexity = 9 * pe->passed_count()
+ + 11 * pos.count<PAWN>()
+ + 9 * outflanking
+ + 21 * pawnsOnBothFlanks
+ + 24 * infiltration
+ + 51 * !pos.non_pawn_material()
+ - 43 * almostUnwinnable
+ - 2 * pos.rule50_count()
+ -110 ;
+
+ Value mg = mg_value(score);
+ Value eg = eg_value(score);
+
+ // Now apply the bonus: note that we find the attacking side by extracting the
+ // sign of the midgame or endgame values, and that we carefully cap the bonus
+ // so that the midgame and endgame scores do not change sign after the bonus.
+ int u = ((mg > 0) - (mg < 0)) * Utility::clamp(complexity + 50, -abs(mg), 0);
int v = ((eg > 0) - (eg < 0)) * std::max(complexity, -abs(eg));
if (T)
- Trace::add(INITIATIVE, make_score(0, v));
+ Trace::add(INITIATIVE, make_score(u, v));
- return make_score(0, v);
+ return make_score(u, v);
}
Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK;
int sf = me->scale_factor(pos, strongSide);
- // If we don't already have an unusual scale factor, check for certain
- // types of endgames, and use a lower scale for those.
- if (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN)
+ // If scale is not already specific, scale down the endgame via general heuristics
+ if (sf == SCALE_FACTOR_NORMAL)
{
if (pos.opposite_bishops())
{
- // Endgame with opposite-colored bishops and no other pieces (ignoring pawns)
- // is almost a draw, in case of KBP vs KB, it is even more a draw.
if ( pos.non_pawn_material(WHITE) == BishopValueMg
&& pos.non_pawn_material(BLACK) == BishopValueMg)
- sf = more_than_one(pos.pieces(PAWN)) ? 31 : 9;
-
- // Endgame with opposite-colored bishops, but also other pieces. Still
- // a bit drawish, but not as drawish as with only the two bishops.
+ sf = 18 + 4 * popcount(pe->passed_pawns(strongSide));
else
- sf = 46;
+ sf = 22 + 3 * pos.count<ALL_PIECES>(strongSide);
}
- // Endings where weaker side can place his king in front of the enemy's
- // pawns are drawish.
- else if ( abs(eg) <= BishopValueEg
- && pos.count<PAWN>(strongSide) <= 2
- && !pos.pawn_passed(~strongSide, pos.square<KING>(~strongSide)))
- sf = 37 + 7 * pos.count<PAWN>(strongSide);
+ else
+ sf = std::min(sf, 36 + 7 * pos.count<PAWN>(strongSide));
}
return ScaleFactor(sf);
// Initialize score by reading the incrementally updated scores included in
// the position object (material + piece square tables) and the material
// imbalance. Score is computed internally from the white point of view.
- Score score = pos.psq_score() + me->imbalance() + Eval::Contempt;
+ Score score = pos.psq_score() + me->imbalance() + pos.this_thread()->contempt;
// Probe the pawn hash table
pe = Pawns::probe(pos);
// Early exit if score is high
Value v = (mg_value(score) + eg_value(score)) / 2;
- if (abs(v) > LazyThreshold)
+ if (abs(v) > LazyThreshold + pos.non_pawn_material() / 64)
return pos.side_to_move() == WHITE ? v : -v;
// Main evaluation begins here
initialize<WHITE>();
initialize<BLACK>();
- // Pieces should be evaluated first (populate attack tables)
+ // Pieces evaluated first (also populates attackedBy, attackedBy2).
+ // Note that the order of evaluation of the terms is left unspecified
score += pieces<WHITE, KNIGHT>() - pieces<BLACK, KNIGHT>()
+ pieces<WHITE, BISHOP>() - pieces<BLACK, BISHOP>()
+ pieces<WHITE, ROOK >() - pieces<BLACK, ROOK >()
score += mobility[WHITE] - mobility[BLACK];
+ // More complex interactions that require fully populated attack bitboards
score += king< WHITE>() - king< BLACK>()
+ threats<WHITE>() - threats<BLACK>()
+ passed< WHITE>() - passed< BLACK>()
+ space< WHITE>() - space< BLACK>();
- score += initiative(eg_value(score));
+ score += initiative(score);
// Interpolate between a middlegame and a (scaled by 'sf') endgame score
ScaleFactor sf = scale_factor(eg_value(score));
v = mg_value(score) * int(me->game_phase())
+ eg_value(score) * int(PHASE_MIDGAME - me->game_phase()) * sf / SCALE_FACTOR_NORMAL;
- v /= int(PHASE_MIDGAME);
+ v /= PHASE_MIDGAME;
// In case of tracing add all remaining individual evaluation terms
if (T)
Trace::add(TOTAL, score);
}
- return pos.side_to_move() == WHITE ? v : -v; // Side to move point of view
+ // Side to move point of view
+ return (pos.side_to_move() == WHITE ? v : -v) + Tempo;
}
} // namespace
/// evaluation of the position from the point of view of the side to move.
Value Eval::evaluate(const Position& pos) {
- return Evaluation<NO_TRACE>(pos).value() + Eval::Tempo;
+ return Evaluation<NO_TRACE>(pos).value();
}
std::string Eval::trace(const Position& pos) {
+ if (pos.checkers())
+ return "Total evaluation: none (in check)";
+
std::memset(scores, 0, sizeof(scores));
- Eval::Contempt = SCORE_ZERO; // Reset any dynamic contempt
+ pos.this_thread()->contempt = SCORE_ZERO; // Reset any dynamic contempt
- Value v = Evaluation<TRACE>(pos).value() + Eval::Tempo;
+ Value v = Evaluation<TRACE>(pos).value();
v = pos.side_to_move() == WHITE ? v : -v; // Trace scores are from white's point of view
<< " ------------+-------------+-------------+------------\n"
<< " Material | " << Term(MATERIAL)
<< " Imbalance | " << Term(IMBALANCE)
- << " Initiative | " << Term(INITIATIVE)
<< " Pawns | " << Term(PAWN)
<< " Knights | " << Term(KNIGHT)
<< " Bishops | " << Term(BISHOP)
<< " Threats | " << Term(THREAT)
<< " Passed | " << Term(PASSED)
<< " Space | " << Term(SPACE)
+ << " Initiative | " << Term(INITIATIVE)
<< " ------------+-------------+-------------+------------\n"
<< " Total | " << Term(TOTAL);