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) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2015-2018 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"
+#include "thread.h"
-namespace {
+namespace Trace {
- namespace Trace {
+ enum Tracing { NO_TRACE, TRACE };
- enum Term { // The first 8 entries are for PieceType
- MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERM_NB
- };
+ enum Term { // The first 8 entries are reserved for PieceType
+ MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, INITIATIVE, TOTAL, TERM_NB
+ };
- double scores[TERM_NB][COLOR_NB][PHASE_NB];
+ Score scores[TERM_NB][COLOR_NB];
- double to_cp(Value v) { return double(v) / PawnValueEg; }
+ double to_cp(Value v) { return double(v) / PawnValueEg; }
- void add(int idx, Color c, Score s) {
- scores[idx][c][MG] = to_cp(mg_value(s));
- scores[idx][c][EG] = to_cp(eg_value(s));
- }
+ void add(int idx, Color c, Score s) {
+ scores[idx][c] = s;
+ }
- void add(int idx, Score w, Score b = SCORE_ZERO) {
- add(idx, WHITE, w); add(idx, BLACK, b);
- }
+ void add(int idx, Score w, Score b = SCORE_ZERO) {
+ scores[idx][WHITE] = w;
+ scores[idx][BLACK] = b;
+ }
- std::ostream& operator<<(std::ostream& os, Term t) {
+ std::ostream& operator<<(std::ostream& os, Score s) {
+ os << std::setw(5) << to_cp(mg_value(s)) << " "
+ << std::setw(5) << to_cp(eg_value(s));
+ return os;
+ }
- if (t == MATERIAL || t == IMBALANCE || t == Term(PAWN) || t == TOTAL)
- os << " --- --- | --- --- | ";
- else
- os << std::setw(5) << scores[t][WHITE][MG] << " "
- << std::setw(5) << scores[t][WHITE][EG] << " | "
- << std::setw(5) << scores[t][BLACK][MG] << " "
- << std::setw(5) << scores[t][BLACK][EG] << " | ";
+ std::ostream& operator<<(std::ostream& os, Term t) {
- os << std::setw(5) << scores[t][WHITE][MG] - scores[t][BLACK][MG] << " "
- << std::setw(5) << scores[t][WHITE][EG] - scores[t][BLACK][EG] << " \n";
+ if (t == MATERIAL || t == IMBALANCE || t == INITIATIVE || t == TOTAL)
+ os << " ---- ----" << " | " << " ---- ----";
+ else
+ os << scores[t][WHITE] << " | " << scores[t][BLACK];
- return os;
- }
+ os << " | " << scores[t][WHITE] - scores[t][BLACK] << "\n";
+ return os;
}
+}
- using namespace Trace;
-
- // Struct EvalInfo contains various information computed and collected
- // by the evaluation functions.
- struct EvalInfo {
+using namespace Trace;
- Material::Entry* me;
- Pawns::Entry* pe;
- Bitboard mobilityArea[COLOR_NB];
+namespace {
- // attackedBy[color][piece type] is a bitboard representing all squares
- // attacked by a given color and piece type (can be also ALL_PIECES).
- Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB];
+ constexpr Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB;
+ constexpr Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB;
+ constexpr Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB;
+ constexpr Bitboard Center = (FileDBB | FileEBB) & (Rank4BB | Rank5BB);
- // 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.
- Bitboard attackedBy2[COLOR_NB];
-
- // kingRing[color] is the zone around the king which is considered
- // by the king safety evaluation. This consists of the squares directly
- // adjacent to the king, and (only for a king on its first rank) the
- // squares two ranks in front of the king. For instance, if black's king
- // is on g8, kingRing[BLACK] is a bitboard containing the squares f8, h8,
- // f7, g7, h7, f6, g6 and h6.
- Bitboard kingRing[COLOR_NB];
+ constexpr Bitboard KingFlank[FILE_NB] = {
+ QueenSide ^ FileDBB, QueenSide, QueenSide,
+ CenterFiles, CenterFiles,
+ KingSide, KingSide, KingSide ^ FileEBB
+ };
- // 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];
+ // Threshold for lazy and space evaluation
+ constexpr Value LazyThreshold = Value(1500);
+ constexpr Value SpaceThreshold = Value(12222);
- // 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];
+ // KingAttackWeights[PieceType] contains king attack weights by piece type
+ constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 77, 55, 44, 10 };
- // 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];
- };
+ // Penalties for enemy's safe checks
+ constexpr int QueenSafeCheck = 780;
+ constexpr int RookSafeCheck = 880;
+ constexpr int BishopSafeCheck = 435;
+ constexpr int KnightSafeCheck = 790;
- #define V(v) Value(v)
- #define S(mg, eg) make_score(mg, eg)
+#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] = {
+ constexpr 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
};
// Outpost[knight/bishop][supported by pawn] contains bonuses for minor
- // pieces if they can reach an outpost square, bigger if that square is
- // supported by a pawn. If the minor piece occupies an outpost square
- // then score is doubled.
- const Score Outpost[][2] = {
- { S(22, 6), S(33, 9) }, // Knight
- { S( 9, 2), S(14, 4) } // Bishop
+ // pieces if they occupy or can reach an outpost square, bigger if that
+ // square is supported by a pawn.
+ constexpr Score Outpost[][2] = {
+ { S(22, 6), S(36,12) }, // Knight
+ { S( 9, 2), S(15, 5) } // Bishop
};
- // 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) };
+ // RookOnFile[semiopen/open] contains bonuses for each rook when there is
+ // no (friendly) pawn on the rook file.
+ constexpr Score RookOnFile[] = { S(20, 7), S(45, 20) };
// 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, 33), S(45, 43), S(46, 47), S(72, 107), S(48, 118)
+ constexpr Score ThreatByMinor[PIECE_TYPE_NB] = {
+ S(0, 0), S(0, 31), S(39, 42), S(57, 44), S(68, 112), S(47, 120)
};
- const Score ThreatByRook[PIECE_TYPE_NB] = {
- S(0, 0), S(0, 25), S(40, 62), S(40, 59), S( 0, 34), S(35, 48)
+ constexpr Score ThreatByRook[PIECE_TYPE_NB] = {
+ S(0, 0), S(0, 24), S(38, 71), S(38, 61), S(0, 38), S(36, 38)
};
- // ThreatByKing[on one/on many] contains bonuses for king attacks on
- // pawns or pieces which are not pawn-defended.
- const Score ThreatByKing[] = { S(3, 62), S(9, 138) };
-
- // Passed[mg/eg][Rank] contains midgame and endgame bonuses for passed pawns.
- // We don't use a Score because we process the two components independently.
- const Value Passed[][RANK_NB] = {
- { V(5), V( 5), V(31), V(73), V(166), V(252) },
- { V(7), V(14), V(38), V(73), V(166), V(252) }
+ // PassedRank[Rank] contains a bonus according to the rank of a passed pawn
+ constexpr Score PassedRank[RANK_NB] = {
+ S(0, 0), S(5, 18), S(12, 23), S(10, 31), S(57, 62), S(163, 167), S(271, 250)
};
// 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 PassedFile[FILE_NB] = {
+ S( -1, 7), S( 0, 9), S(-9, -8), S(-30,-14),
+ S(-30,-14), S(-9, -8), S( 0, 9), S( -1, 7)
};
- // KingProtector[PieceType-2] contains a bonus according to distance from king
- const Score KingProtector[] = { S(-3, -5), S(-4, -3), S(-3, 0), S(-1, 1) };
-
- // Assorted bonuses and penalties used by evaluation
- const Score MinorBehindPawn = S( 16, 0);
- const Score BishopPawns = S( 8, 12);
- const Score RookOnPawn = S( 8, 24);
- const Score TrappedRook = S( 92, 0);
- const Score WeakQueen = S( 50, 10);
- const Score OtherCheck = S( 10, 10);
- const Score CloseEnemies = S( 7, 0);
- const Score PawnlessFlank = S( 20, 80);
- const Score ThreatByHangingPawn = S( 71, 61);
- const Score ThreatBySafePawn = S(182,175);
- const Score ThreatByRank = S( 16, 3);
- const Score Hanging = S( 48, 27);
- const Score ThreatByPawnPush = S( 38, 22);
- const Score HinderPassedPawn = S( 7, 0);
-
- // 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
- // happen in Chess960 games.
- const Score TrappedBishopA1H1 = S(50, 50);
-
- #undef S
- #undef V
+ // PassedDanger[Rank] contains a term to weight the passed score
+ constexpr int PassedDanger[RANK_NB] = { 0, 0, 0, 3, 7, 11, 20 };
+
+ // Assorted bonuses and penalties
+ constexpr Score BishopPawns = S( 3, 7);
+ constexpr Score CloseEnemies = S( 6, 0);
+ constexpr Score CorneredBishop = S( 50, 50);
+ constexpr Score Hanging = S( 57, 32);
+ constexpr Score HinderPassedPawn = S( 8, 0);
+ constexpr Score KingProtector = S( 6, 6);
+ constexpr Score KnightOnQueen = S( 21, 11);
+ constexpr Score LongDiagonalBishop = S( 22, 0);
+ constexpr Score MinorBehindPawn = S( 16, 0);
+ constexpr Score Overload = S( 13, 6);
+ constexpr Score PawnlessFlank = S( 19, 84);
+ constexpr Score RookOnPawn = S( 10, 30);
+ constexpr Score SliderOnQueen = S( 42, 21);
+ constexpr Score ThreatByKing = S( 23, 76);
+ constexpr Score ThreatByPawnPush = S( 45, 40);
+ constexpr Score ThreatByRank = S( 16, 3);
+ constexpr Score ThreatBySafePawn = S(173,102);
+ constexpr Score TrappedRook = S( 92, 0);
+ constexpr Score WeakQueen = S( 50, 10);
+ constexpr Score WeakUnopposedPawn = S( 5, 29);
+
+#undef S
+
+ // Evaluation class computes and stores attacks tables and other working data
+ template<Tracing T>
+ class Evaluation {
+
+ public:
+ Evaluation() = delete;
+ explicit Evaluation(const Position& p) : pos(p) {}
+ Evaluation& operator=(const Evaluation&) = delete;
+ Value value();
+
+ private:
+ template<Color Us> void initialize();
+ template<Color Us, PieceType Pt> Score pieces();
+ template<Color Us> Score king() const;
+ template<Color Us> Score threats() const;
+ template<Color Us> Score passed() const;
+ template<Color Us> Score space() const;
+ ScaleFactor scale_factor(Value eg) const;
+ Score initiative(Value eg) const;
+
+ const Position& pos;
+ Material::Entry* me;
+ Pawns::Entry* pe;
+ Bitboard mobilityArea[COLOR_NB];
+ Score mobility[COLOR_NB] = { SCORE_ZERO, SCORE_ZERO };
- // KingAttackWeights[PieceType] contains king attack weights by piece type
- const int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 78, 56, 45, 11 };
+ // attackedBy[color][piece type] is a bitboard representing all squares
+ // attacked by a given color and piece type. Special "piece types" which
+ // is also calculated is ALL_PIECES.
+ Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB];
- // Penalties for enemy's safe checks
- const int QueenCheck = 780;
- const int RookCheck = 880;
- const int BishopCheck = 435;
- const int KnightCheck = 790;
+ // 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.
+ Bitboard attackedBy2[COLOR_NB];
- // Threshold for lazy and space evaluation
- const Value LazyThreshold = Value(1500);
- const Value SpaceThreshold = Value(12222);
+ // 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.
+ 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.
+ int kingAttackersWeight[COLOR_NB];
+
+ // 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 kingAttacksCount[WHITE].
+ int kingAttacksCount[COLOR_NB];
+ };
- // eval_init() initializes king and attack bitboards for a given color
- // adding pawn attacks. To be done at the beginning of the evaluation.
- template<Color Us>
- void eval_init(const Position& pos, EvalInfo& ei) {
+ // Evaluation::initialize() computes king and pawn attacks, and the king ring
+ // bitboard for a given color. This is done at the beginning of the evaluation.
+ template<Tracing T> template<Color Us>
+ void Evaluation<T>::initialize() {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Square Up = (Us == WHITE ? NORTH : SOUTH);
- const Square Down = (Us == WHITE ? SOUTH : NORTH);
- const Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB: Rank7BB | Rank6BB);
+ constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Direction Up = (Us == WHITE ? NORTH : SOUTH);
+ constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH);
+ constexpr Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB: Rank7BB | Rank6BB);
- // Find our pawns on the first two ranks, and those which are blocked
+ // 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
+ // Squares occupied by those pawns, by our king or queen, or controlled by enemy pawns
// are excluded from the mobility area.
- ei.mobilityArea[Us] = ~(b | pos.square<KING>(Us) | ei.pe->pawn_attacks(Them));
+ mobilityArea[Us] = ~(b | pos.pieces(Us, KING, QUEEN) | pe->pawn_attacks(Them));
- // Initialise the attack bitboards with the king and pawn information
- b = ei.attackedBy[Us][KING] = pos.attacks_from<KING>(pos.square<KING>(Us));
- ei.attackedBy[Us][PAWN] = ei.pe->pawn_attacks(Us);
-
- ei.attackedBy2[Us] = b & ei.attackedBy[Us][PAWN];
- ei.attackedBy[Us][ALL_PIECES] = b | ei.attackedBy[Us][PAWN];
+ // Initialise attackedBy bitboards for kings and pawns
+ attackedBy[Us][KING] = pos.attacks_from<KING>(pos.square<KING>(Us));
+ 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];
// Init our king safety tables only if we are going to use them
if (pos.non_pawn_material(Them) >= RookValueMg + KnightValueMg)
{
- ei.kingRing[Us] = b;
+ kingRing[Us] = attackedBy[Us][KING];
if (relative_rank(Us, pos.square<KING>(Us)) == RANK_1)
- ei.kingRing[Us] |= shift<Up>(b);
+ kingRing[Us] |= shift<Up>(kingRing[Us]);
+
+ if (file_of(pos.square<KING>(Us)) == FILE_H)
+ kingRing[Us] |= shift<WEST>(kingRing[Us]);
- ei.kingAttackersCount[Them] = popcount(b & ei.pe->pawn_attacks(Them));
- ei.kingAdjacentZoneAttacksCount[Them] = ei.kingAttackersWeight[Them] = 0;
+ else if (file_of(pos.square<KING>(Us)) == FILE_A)
+ kingRing[Us] |= shift<EAST>(kingRing[Us]);
+
+ kingAttackersCount[Them] = popcount(kingRing[Us] & pe->pawn_attacks(Them));
+ kingAttacksCount[Them] = kingAttackersWeight[Them] = 0;
}
else
- ei.kingRing[Us] = ei.kingAttackersCount[Them] = 0;
+ kingRing[Us] = kingAttackersCount[Them] = 0;
}
- // evaluate_pieces() assigns bonuses and penalties to the pieces of a given
- // color and type.
-
- template<bool DoTrace, Color Us = WHITE, PieceType Pt = KNIGHT>
- Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility) {
+ // Evaluation::pieces() scores pieces of a given color and type
+ template<Tracing T> template<Color Us, PieceType Pt>
+ Score Evaluation<T>::pieces() {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const PieceType NextPt = (Us == WHITE ? Pt : PieceType(Pt + 1));
- const Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB
- : Rank5BB | Rank4BB | Rank3BB);
+ constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH);
+ 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;
- ei.attackedBy[Us][Pt] = 0;
+ attackedBy[Us][Pt] = 0;
while ((s = *pl++) != SQ_NONE)
{
// Find attacked squares, including x-ray attacks for bishops and rooks
- b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(Us, QUEEN))
- : Pt == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN))
+ b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(QUEEN))
+ : Pt == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(QUEEN) ^ pos.pieces(Us, ROOK))
: pos.attacks_from<Pt>(s);
- if (pos.pinned_pieces(Us) & s)
+ if (pos.blockers_for_king(Us) & s)
b &= LineBB[pos.square<KING>(Us)][s];
- ei.attackedBy2[Us] |= ei.attackedBy[Us][ALL_PIECES] & b;
- ei.attackedBy[Us][ALL_PIECES] |= ei.attackedBy[Us][Pt] |= b;
+ attackedBy2[Us] |= attackedBy[Us][ALL_PIECES] & b;
+ attackedBy[Us][Pt] |= b;
+ attackedBy[Us][ALL_PIECES] |= b;
- if (b & ei.kingRing[Them])
+ if (b & kingRing[Them])
{
- ei.kingAttackersCount[Us]++;
- ei.kingAttackersWeight[Us] += KingAttackWeights[Pt];
- ei.kingAdjacentZoneAttacksCount[Us] += popcount(b & ei.attackedBy[Them][KING]);
+ kingAttackersCount[Us]++;
+ kingAttackersWeight[Us] += KingAttackWeights[Pt];
+ kingAttacksCount[Us] += popcount(b & attackedBy[Them][KING]);
}
- int mob = popcount(b & ei.mobilityArea[Us]);
+ int mob = popcount(b & mobilityArea[Us]);
mobility[Us] += MobilityBonus[Pt - 2][mob];
- // Bonus for this piece as a king protector
- score += KingProtector[Pt - 2] * distance(s, pos.square<KING>(Us));
-
if (Pt == BISHOP || Pt == KNIGHT)
{
- // Bonus for outpost squares
- bb = OutpostRanks & ~ei.pe->pawn_attacks_span(Them);
+ // Bonus if piece is on an outpost square or can reach one
+ bb = OutpostRanks & ~pe->pawn_attacks_span(Them);
if (bb & s)
- score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)] * 2;
- else
- {
- bb &= b & ~pos.pieces(Us);
- if (bb)
- score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & bb)];
- }
+ score += Outpost[Pt == BISHOP][bool(attackedBy[Us][PAWN] & s)] * 2;
- // Bonus when behind a pawn
- if ( relative_rank(Us, s) < RANK_5
- && (pos.pieces(PAWN) & (s + pawn_push(Us))))
+ else if (bb &= b & ~pos.pieces(Us))
+ score += Outpost[Pt == BISHOP][bool(attackedBy[Us][PAWN] & bb)];
+
+ // Knight and Bishop bonus for being right behind a pawn
+ if (shift<Down>(pos.pieces(PAWN)) & s)
score += MinorBehindPawn;
- // Penalty for pawns on the same color square as the bishop
+ // Penalty if the piece is far from the king
+ score -= KingProtector * distance(s, pos.square<KING>(Us));
+
if (Pt == BISHOP)
- score -= BishopPawns * ei.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.
+ Bitboard blocked = pos.pieces(Us, PAWN) & shift<Down>(pos.pieces());
+
+ score -= BishopPawns * pe->pawns_on_same_color_squares(Us, s)
+ * (1 + popcount(blocked & CenterFiles));
+
+ // 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 += LongDiagonalBishop;
+ }
// An important Chess960 pattern: A cornered bishop blocked by a friendly
// pawn diagonally in front of it is a very serious problem, especially
&& pos.is_chess960()
&& (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
{
- Square d = pawn_push(Us) + (file_of(s) == FILE_A ? EAST : WEST);
+ 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;
+ 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 with enemy pawns on the same rank/file
+ // Bonus for aligning rook 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 when on an open or semi-open file
- if (ei.pe->semiopen_file(Us, file_of(s)))
- score += RookOnFile[!!ei.pe->semiopen_file(Them, file_of(s))];
+ // 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)))];
// Penalty when trapped by the king, even more if the king cannot castle
else if (mob <= 3)
{
- Square ksq = pos.square<KING>(Us);
-
- if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
- && !ei.pe->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq)))
+ 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));
}
}
if (Pt == QUEEN)
{
// Penalty if any relative pin or discovered attack against the queen
- Bitboard pinners;
- if (pos.slider_blockers(pos.pieces(Them, ROOK, BISHOP), s, pinners))
+ Bitboard queenPinners;
+ if (pos.slider_blockers(pos.pieces(Them, ROOK, BISHOP), s, queenPinners))
score -= WeakQueen;
}
}
-
- if (DoTrace)
+ if (T)
Trace::add(Pt, Us, score);
- // Recursively call evaluate_pieces() of next piece type until KING is excluded
- return score - evaluate_pieces<DoTrace, Them, NextPt>(pos, ei, mobility);
+ return score;
}
- template<>
- Score evaluate_pieces<false, WHITE, KING>(const Position&, EvalInfo&, Score*) { return SCORE_ZERO; }
- template<>
- Score evaluate_pieces< true, WHITE, KING>(const Position&, EvalInfo&, Score*) { return SCORE_ZERO; }
-
-
- // evaluate_king() assigns bonuses and penalties to a king of a given color
-
- const Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB;
- const Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB;
- const Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB;
-
- const Bitboard KingFlank[FILE_NB] = {
- QueenSide, QueenSide, QueenSide, CenterFiles, CenterFiles, KingSide, KingSide, KingSide
- };
- template<Color Us, bool DoTrace>
- Score evaluate_king(const Position& pos, const EvalInfo& ei) {
+ // Evaluation::king() assigns bonuses and penalties to a king of a given color
+ template<Tracing T> template<Color Us>
+ Score Evaluation<T>::king() const {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Square Up = (Us == WHITE ? NORTH : SOUTH);
- const Bitboard Camp = (Us == WHITE ? ~Bitboard(0) ^ Rank6BB ^ Rank7BB ^ Rank8BB
- : ~Bitboard(0) ^ Rank1BB ^ Rank2BB ^ Rank3BB);
+ constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Bitboard Camp = (Us == WHITE ? AllSquares ^ Rank6BB ^ Rank7BB ^ Rank8BB
+ : AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB);
const Square ksq = pos.square<KING>(Us);
- Bitboard undefended, b, b1, b2, safe, other;
- int kingDanger;
+ Bitboard kingFlank, weak, b, b1, b2, safe, unsafeChecks;
// King shelter and enemy pawns storm
- Score score = ei.pe->king_safety<Us>(pos, ksq);
+ Score score = pe->king_safety<Us>(pos, ksq);
+
+ // Find the squares that opponent attacks in our king flank, and the squares
+ // which are attacked twice in that flank but not defended by our pawns.
+ kingFlank = KingFlank[file_of(ksq)];
+ b1 = attackedBy[Them][ALL_PIECES] & kingFlank & Camp;
+ b2 = b1 & attackedBy2[Them] & ~attackedBy[Us][PAWN];
+
+ int tropism = popcount(b1) + popcount(b2);
// Main king safety evaluation
- if (ei.kingAttackersCount[Them] > (1 - pos.count<QUEEN>(Them)))
+ if (kingAttackersCount[Them] > 1 - pos.count<QUEEN>(Them))
{
- // Find the attacked squares which are defended only by our king...
- undefended = ei.attackedBy[Them][ALL_PIECES]
- & ei.attackedBy[Us][KING]
- & ~ei.attackedBy2[Us];
-
- // ... and those which are not defended at all in the larger king ring
- b = ei.attackedBy[Them][ALL_PIECES] & ~ei.attackedBy[Us][ALL_PIECES]
- & ei.kingRing[Us] & ~pos.pieces(Them);
-
- // Initialize the 'kingDanger' variable, which will be transformed
- // later into a king danger score. 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 and the quality of
- // the pawn shelter (current 'score' value).
- kingDanger = ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]
- + 102 * ei.kingAdjacentZoneAttacksCount[Them]
- + 201 * popcount(undefended)
- + 143 * (popcount(b) + !!pos.pinned_pieces(Us))
- - 848 * !pos.count<QUEEN>(Them)
- - 9 * mg_value(score) / 8
- + 40;
+ int kingDanger = 0;
+ 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]);
// Analyse the safe enemy's checks which are possible on next move
safe = ~pos.pieces(Them);
- safe &= ~ei.attackedBy[Us][ALL_PIECES] | (undefended & ei.attackedBy2[Them]);
+ safe &= ~attackedBy[Us][ALL_PIECES] | (weak & attackedBy2[Them]);
- b1 = pos.attacks_from<ROOK >(ksq);
- b2 = pos.attacks_from<BISHOP>(ksq);
+ b1 = attacks_bb<ROOK >(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN));
+ b2 = attacks_bb<BISHOP>(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN));
// Enemy queen safe checks
- if ((b1 | b2) & ei.attackedBy[Them][QUEEN] & safe)
- kingDanger += QueenCheck;
-
- // For minors and rooks, also consider the square safe if attacked twice,
- // and only defended by our queen.
- safe |= ei.attackedBy2[Them]
- & ~(ei.attackedBy2[Us] | pos.pieces(Them))
- & ei.attackedBy[Us][QUEEN];
-
- // Some other potential checks are also analysed, even from squares
- // currently occupied by the opponent own pieces, as long as the square
- // is not attacked by our pawns, and is not occupied by a blocked pawn.
- other = ~( ei.attackedBy[Us][PAWN]
- | (pos.pieces(Them, PAWN) & shift<Up>(pos.pieces(PAWN))));
-
- // Enemy rooks safe and other checks
- if (b1 & ei.attackedBy[Them][ROOK] & safe)
- kingDanger += RookCheck;
-
- else if (b1 & ei.attackedBy[Them][ROOK] & other)
- score -= OtherCheck;
-
- // Enemy bishops safe and other checks
- if (b2 & ei.attackedBy[Them][BISHOP] & safe)
- kingDanger += BishopCheck;
-
- else if (b2 & ei.attackedBy[Them][BISHOP] & other)
- score -= OtherCheck;
-
- // Enemy knights safe and other checks
- b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT];
+ if ((b1 | b2) & attackedBy[Them][QUEEN] & safe & ~attackedBy[Us][QUEEN])
+ kingDanger += QueenSafeCheck;
+
+ b1 &= attackedBy[Them][ROOK];
+ b2 &= attackedBy[Them][BISHOP];
+
+ // Enemy rooks checks
+ if (b1 & safe)
+ kingDanger += RookSafeCheck;
+ else
+ unsafeChecks |= b1;
+
+ // Enemy bishops checks
+ if (b2 & safe)
+ kingDanger += BishopSafeCheck;
+ else
+ unsafeChecks |= b2;
+
+ // Enemy knights checks
+ b = pos.attacks_from<KNIGHT>(ksq) & attackedBy[Them][KNIGHT];
if (b & safe)
- kingDanger += KnightCheck;
-
- else if (b & other)
- score -= OtherCheck;
-
- // Transform the kingDanger units into a Score, and substract it from the evaluation
+ 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];
+
+ kingDanger += kingAttackersCount[Them] * kingAttackersWeight[Them]
+ + 69 * kingAttacksCount[Them]
+ + 185 * popcount(kingRing[Us] & weak)
+ + 129 * popcount(pos.blockers_for_king(Us) | unsafeChecks)
+ + 4 * tropism
+ - 873 * !pos.count<QUEEN>(Them)
+ - 6 * mg_value(score) / 8
+ - 30;
+
+ // 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);
+ }
}
- // King tropism: firstly, find squares that opponent attacks in our king flank
- File kf = file_of(ksq);
- b = ei.attackedBy[Them][ALL_PIECES] & KingFlank[kf] & 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 & ei.attackedBy2[Them] & ~ei.attackedBy[Us][PAWN]);
-
- score -= CloseEnemies * popcount(b);
-
// Penalty when our king is on a pawnless flank
- if (!(pos.pieces(PAWN) & KingFlank[kf]))
+ if (!(pos.pieces(PAWN) & kingFlank))
score -= PawnlessFlank;
- if (DoTrace)
+ // King tropism bonus, to anticipate slow motion attacks on our king
+ score -= CloseEnemies * tropism;
+
+ if (T)
Trace::add(KING, Us, score);
return score;
}
- // evaluate_threats() assigns bonuses according to the types of the attacking
- // and the attacked pieces.
-
- template<Color Us, bool DoTrace>
- Score evaluate_threats(const Position& pos, const EvalInfo& ei) {
+ // Evaluation::threats() assigns bonuses according to the types of the
+ // attacking and the attacked pieces.
+ template<Tracing T> template<Color Us>
+ Score Evaluation<T>::threats() const {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Square Up = (Us == WHITE ? NORTH : SOUTH);
- const Square Left = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
- const Square Right = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
- const Bitboard TRank2BB = (Us == WHITE ? Rank2BB : Rank7BB);
- const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
+ constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Direction Up = (Us == WHITE ? NORTH : SOUTH);
+ constexpr Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
- Bitboard b, weak, defended, stronglyProtected, safeThreats;
+ Bitboard b, weak, defended, nonPawnEnemies, stronglyProtected, safe;
Score score = SCORE_ZERO;
- // Non-pawn enemies attacked by a pawn
- weak = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Us][PAWN];
+ // Non-pawn enemies
+ nonPawnEnemies = pos.pieces(Them) ^ pos.pieces(Them, PAWN);
- if (weak)
- {
- b = pos.pieces(Us, PAWN) & ( ~ei.attackedBy[Them][ALL_PIECES]
- | ei.attackedBy[Us][ALL_PIECES]);
-
- safeThreats = (shift<Right>(b) | shift<Left>(b)) & weak;
-
- score += ThreatBySafePawn * popcount(safeThreats);
-
- if (weak ^ safeThreats)
- score += ThreatByHangingPawn;
- }
-
- // Squares strongly protected by the opponent, either because they attack the
- // square with a pawn, or because they attack the square twice and we don't.
- stronglyProtected = ei.attackedBy[Them][PAWN]
- | (ei.attackedBy2[Them] & ~ei.attackedBy2[Us]);
+ // 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.
+ stronglyProtected = attackedBy[Them][PAWN]
+ | (attackedBy2[Them] & ~attackedBy2[Us]);
// Non-pawn enemies, strongly protected
- defended = (pos.pieces(Them) ^ pos.pieces(Them, PAWN))
- & stronglyProtected;
+ defended = nonPawnEnemies & stronglyProtected;
// Enemies not strongly protected and under our attack
- weak = pos.pieces(Them)
- & ~stronglyProtected
- & ei.attackedBy[Us][ALL_PIECES];
+ weak = pos.pieces(Them) & ~stronglyProtected & attackedBy[Us][ALL_PIECES];
+
+ // Safe or protected squares
+ safe = ~attackedBy[Them][ALL_PIECES] | attackedBy[Us][ALL_PIECES];
- // Add a bonus according to the kind of attacking pieces
+ // Bonus according to the kind of attacking pieces
if (defended | weak)
{
- b = (defended | weak) & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
+ 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);
+
+ else if (pos.blockers_for_king(Them) & s)
+ score += ThreatByRank * (int)relative_rank(Them, s) / 2;
}
- b = (pos.pieces(Them, QUEEN) | weak) & ei.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);
+
+ else if (pos.blockers_for_king(Them) & s)
+ score += ThreatByRank * (int)relative_rank(Them, s) / 2;
}
- score += Hanging * popcount(weak & ~ei.attackedBy[Them][ALL_PIECES]);
+ if (weak & attackedBy[Us][KING])
+ score += ThreatByKing;
+
+ score += Hanging * popcount(weak & ~attackedBy[Them][ALL_PIECES]);
- b = weak & ei.attackedBy[Us][KING];
- if (b)
- score += ThreatByKing[more_than_one(b)];
+ b = weak & nonPawnEnemies & attackedBy[Them][ALL_PIECES];
+ score += Overload * popcount(b);
}
- // Bonus if some pawns can safely push and attack an enemy piece
- b = pos.pieces(Us, PAWN) & ~TRank7BB;
- b = shift<Up>(b | (shift<Up>(b & TRank2BB) & ~pos.pieces()));
+ // Bonus for enemy unopposed weak pawns
+ if (pos.pieces(Us, ROOK, QUEEN))
+ score += WeakUnopposedPawn * pe->weak_unopposed(Them);
- b &= ~pos.pieces()
- & ~ei.attackedBy[Them][PAWN]
- & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
+ // 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();
- b = (shift<Left>(b) | shift<Right>(b))
- & pos.pieces(Them)
- & ~ei.attackedBy[Us][PAWN];
+ // 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);
score += ThreatByPawnPush * popcount(b);
- if (DoTrace)
+ // Our safe or protected pawns
+ b = pos.pieces(Us, PAWN) & safe;
+
+ b = pawn_attacks_bb<Us>(b) & nonPawnEnemies;
+ score += ThreatBySafePawn * popcount(b);
+
+ // 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);
+
+ 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);
return score;
}
-
- // evaluate_passer_pawns() evaluates the passed pawns and candidate passed
+ // Evaluation::passed() evaluates the passed pawns and candidate passed
// pawns of the given color.
- template<Color Us, bool DoTrace>
- Score evaluate_passer_pawns(const Position& pos, const EvalInfo& ei) {
+ template<Tracing T> template<Color Us>
+ Score Evaluation<T>::passed() const {
+
+ constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Direction Up = (Us == WHITE ? NORTH : SOUTH);
- const Color Them = (Us == WHITE ? BLACK : WHITE);
+ auto king_proximity = [&](Color c, Square s) {
+ return std::min(distance(pos.square<KING>(c), s), 5);
+ };
Bitboard b, bb, squaresToQueen, defendedSquares, unsafeSquares;
Score score = SCORE_ZERO;
- b = ei.pe->passed_pawns(Us);
+ b = pe->passed_pawns(Us);
while (b)
{
Square s = pop_lsb(&b);
- assert(!(pos.pieces(Them, PAWN) & forward_bb(Us, s + pawn_push(Us))));
+ assert(!(pos.pieces(Them, PAWN) & forward_file_bb(Us, s + Up)));
- bb = forward_bb(Us, s) & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
- score -= HinderPassedPawn * popcount(bb);
+ if (forward_file_bb(Us, s) & pos.pieces(Them))
+ score -= HinderPassedPawn;
- int r = relative_rank(Us, s) - RANK_2;
- int rr = r * (r - 1);
+ int r = relative_rank(Us, s);
+ int w = PassedDanger[r];
- Value mbonus = Passed[MG][r], ebonus = Passed[EG][r];
+ Score bonus = PassedRank[r];
- if (rr)
+ if (w)
{
- Square blockSq = s + pawn_push(Us);
+ Square blockSq = s + Up;
// Adjust bonus based on the king's proximity
- ebonus += distance(pos.square<KING>(Them), blockSq) * 5 * rr
- - distance(pos.square<KING>(Us ), blockSq) * 2 * rr;
+ bonus += make_score(0, ( king_proximity(Them, blockSq) * 5
+ - king_proximity(Us, blockSq) * 2) * w);
// If blockSq is not the queening square then consider also a second push
- if (relative_rank(Us, blockSq) != RANK_8)
- ebonus -= distance(pos.square<KING>(Us), blockSq + pawn_push(Us)) * rr;
+ if (r != RANK_7)
+ bonus -= make_score(0, king_proximity(Us, blockSq + Up) * w);
// 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_bb(Us, s);
+ defendedSquares = unsafeSquares = squaresToQueen = forward_file_bb(Us, s);
- bb = forward_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from<ROOK>(s);
+ bb = forward_file_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from<ROOK>(s);
if (!(pos.pieces(Us) & bb))
- defendedSquares &= ei.attackedBy[Us][ALL_PIECES];
+ defendedSquares &= attackedBy[Us][ALL_PIECES];
if (!(pos.pieces(Them) & bb))
- unsafeSquares &= ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them);
+ 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 ? 18 : !(unsafeSquares & blockSq) ? 8 : 0;
+ int k = !unsafeSquares ? 20 : !(unsafeSquares & blockSq) ? 9 : 0;
// If the path to the queen is fully defended, assign a big bonus.
// Otherwise assign a smaller bonus if the block square is defended.
else if (defendedSquares & blockSq)
k += 4;
- mbonus += k * rr, ebonus += k * rr;
+ bonus += make_score(k * w, k * w);
}
else if (pos.pieces(Us) & blockSq)
- mbonus += rr + r * 2, ebonus += rr + r * 2;
- } // rr != 0
+ bonus += make_score(w + r * 2, w + r * 2);
+ } // w != 0
// 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 + pawn_push(Us)) || (pos.pieces(PAWN) & forward_bb(Us, s)))
- mbonus /= 2, ebonus /= 2;
+ // 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 += make_score(mbonus, ebonus) + PassedFile[file_of(s)];
+ score += bonus + PassedFile[file_of(s)];
}
- if (DoTrace)
+ if (T)
Trace::add(PASSED, Us, score);
return score;
}
- // evaluate_space() computes the space evaluation for a given side. The
+ // Evaluation::space() computes the space evaluation for a given side. The
// space evaluation is a simple bonus based on the number of safe squares
// available for minor pieces on the central four files on ranks 2--4. Safe
// squares one, two or three squares behind a friendly pawn are counted
// twice. Finally, the space bonus is multiplied by a weight. The aim is to
// improve play on game opening.
- template<Color Us>
- Score evaluate_space(const Position& pos, const EvalInfo& ei) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Bitboard SpaceMask =
+ template<Tracing T> template<Color Us>
+ Score Evaluation<T>::space() const {
+
+ if (pos.non_pawn_material() < SpaceThreshold)
+ return SCORE_ZERO;
+
+ constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Bitboard SpaceMask =
Us == WHITE ? CenterFiles & (Rank2BB | Rank3BB | Rank4BB)
: CenterFiles & (Rank7BB | Rank6BB | Rank5BB);
- // 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.
+ // Find the available squares for our pieces inside the area defined by SpaceMask
Bitboard safe = SpaceMask
& ~pos.pieces(Us, PAWN)
- & ~ei.attackedBy[Them][PAWN]
- & (ei.attackedBy[Us][ALL_PIECES] | ~ei.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);
+ int bonus = popcount(safe) + popcount(behind & safe);
+ int weight = pos.count<ALL_PIECES>(Us) - 2 * pe->open_files();
- // ...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 * ei.pe->open_files();
+ Score score = make_score(bonus * weight * weight / 16, 0);
- return make_score(bonus * weight * weight / 16, 0);
+ if (T)
+ Trace::add(SPACE, Us, score);
+
+ return score;
}
- // evaluate_initiative() computes the initiative correction value for the
- // position, i.e., second order bonus/malus based on the known attacking/defending
- // status of the players.
- Score evaluate_initiative(const Position& pos, int asymmetry, Value eg) {
+ // Evaluation::initiative() computes the initiative correction value
+ // for the position. It is a second order bonus/malus based on the
+ // known attacking/defending status of the players.
+
+ template<Tracing T>
+ Score Evaluation<T>::initiative(Value eg) const {
- int kingDistance = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
- - distance<Rank>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
- bool bothFlanks = (pos.pieces(PAWN) & QueenSide) && (pos.pieces(PAWN) & KingSide);
+ 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);
// Compute the initiative bonus for the attacking side
- int initiative = 8 * (asymmetry + kingDistance - 17) + 12 * pos.count<PAWN>() + 16 * bothFlanks;
+ int complexity = 8 * pe->pawn_asymmetry()
+ + 12 * pos.count<PAWN>()
+ + 12 * outflanking
+ + 16 * pawnsOnBothFlanks
+ + 48 * !pos.non_pawn_material()
+ -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 value = ((eg > 0) - (eg < 0)) * std::max(initiative, -abs(eg));
+ int v = ((eg > 0) - (eg < 0)) * std::max(complexity, -abs(eg));
+
+ if (T)
+ Trace::add(INITIATIVE, make_score(0, v));
- return make_score(0, value);
+ return make_score(0, v);
}
- // evaluate_scale_factor() computes the scale factor for the winning side
- ScaleFactor evaluate_scale_factor(const Position& pos, const EvalInfo& ei, Value eg) {
+ // Evaluation::scale_factor() computes the scale factor for the winning side
+
+ template<Tracing T>
+ ScaleFactor Evaluation<T>::scale_factor(Value eg) const {
Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK;
- ScaleFactor sf = ei.me->scale_factor(pos, strongSide);
+ 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)
- return more_than_one(pos.pieces(PAWN)) ? ScaleFactor(31) : ScaleFactor(9);
-
- // Endgame with opposite-colored bishops, but also other pieces. Still
- // a bit drawish, but not as drawish as with only the two bishops.
- return ScaleFactor(46);
- }
- // Endings where weaker side can place his king in front of the opponent's
- // pawns are drawish.
- else if ( abs(eg) <= BishopValueEg
- && pos.count<PAWN>(strongSide) <= 2
- && !pos.pawn_passed(~strongSide, pos.square<KING>(~strongSide)))
- return ScaleFactor(37 + 7 * pos.count<PAWN>(strongSide));
+ if ( pos.opposite_bishops()
+ && pos.non_pawn_material(WHITE) == BishopValueMg
+ && pos.non_pawn_material(BLACK) == BishopValueMg)
+ sf = 31;
+ else
+ sf = std::min(40 + (pos.opposite_bishops() ? 2 : 7) * pos.count<PAWN>(strongSide), sf);
}
- return sf;
+ return ScaleFactor(sf);
}
-} // namespace
+ // Evaluation::value() is the main function of the class. It computes the various
+ // parts of the evaluation and returns the value of the position from the point
+ // of view of the side to move.
-/// evaluate() is the main evaluation function. It returns a static evaluation
-/// of the position from the point of view of the side to move.
+ template<Tracing T>
+ Value Evaluation<T>::value() {
-template<bool DoTrace>
-Value Eval::evaluate(const Position& pos) {
+ assert(!pos.checkers());
+
+ // Probe the material hash table
+ me = Material::probe(pos);
+
+ // If we have a specialized evaluation function for the current material
+ // configuration, call it and return.
+ if (me->specialized_eval_exists())
+ return me->evaluate(pos);
+
+ // 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() + pos.this_thread()->contempt;
+
+ // Probe the pawn hash table
+ pe = Pawns::probe(pos);
+ score += pe->pawn_score(WHITE) - pe->pawn_score(BLACK);
+
+ // Early exit if score is high
+ Value v = (mg_value(score) + eg_value(score)) / 2;
+ if (abs(v) > LazyThreshold)
+ return pos.side_to_move() == WHITE ? v : -v;
- assert(!pos.checkers());
-
- Score mobility[COLOR_NB] = { SCORE_ZERO, SCORE_ZERO };
- Value v;
- EvalInfo ei;
-
- // Probe the material hash table
- ei.me = Material::probe(pos);
-
- // If we have a specialized evaluation function for the current material
- // configuration, call it and return.
- if (ei.me->specialized_eval_exists())
- return ei.me->evaluate(pos);
-
- // 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() + ei.me->imbalance();
-
- // Probe the pawn hash table
- ei.pe = Pawns::probe(pos);
- score += ei.pe->pawns_score();
-
- // Early exit if score is high
- v = (mg_value(score) + eg_value(score)) / 2;
- if (abs(v) > LazyThreshold)
- return pos.side_to_move() == WHITE ? v : -v;
-
- // Initialize attack and king safety bitboards
- eval_init<WHITE>(pos, ei);
- eval_init<BLACK>(pos, ei);
-
- // Evaluate all pieces but king and pawns
- score += evaluate_pieces<DoTrace>(pos, ei, mobility);
- score += mobility[WHITE] - mobility[BLACK];
-
- // Evaluate kings after all other pieces because we need full attack
- // information when computing the king safety evaluation.
- score += evaluate_king<WHITE, DoTrace>(pos, ei)
- - evaluate_king<BLACK, DoTrace>(pos, ei);
-
- // Evaluate tactical threats, we need full attack information including king
- score += evaluate_threats<WHITE, DoTrace>(pos, ei)
- - evaluate_threats<BLACK, DoTrace>(pos, ei);
-
- // Evaluate passed pawns, we need full attack information including king
- score += evaluate_passer_pawns<WHITE, DoTrace>(pos, ei)
- - evaluate_passer_pawns<BLACK, DoTrace>(pos, ei);
-
- // Evaluate space for both sides, only during opening
- if (pos.non_pawn_material() >= SpaceThreshold)
- score += evaluate_space<WHITE>(pos, ei)
- - evaluate_space<BLACK>(pos, ei);
-
- // Evaluate position potential for the winning side
- score += evaluate_initiative(pos, ei.pe->pawn_asymmetry(), eg_value(score));
-
- // Evaluate scale factor for the winning side
- ScaleFactor sf = evaluate_scale_factor(pos, ei, eg_value(score));
-
- // Interpolate between a middlegame and a (scaled by 'sf') endgame score
- v = mg_value(score) * int(ei.me->game_phase())
- + eg_value(score) * int(PHASE_MIDGAME - ei.me->game_phase()) * sf / SCALE_FACTOR_NORMAL;
-
- v /= int(PHASE_MIDGAME);
-
- // In case of tracing add all remaining individual evaluation terms
- if (DoTrace)
- {
- Trace::add(MATERIAL, pos.psq_score());
- Trace::add(IMBALANCE, ei.me->imbalance());
- Trace::add(PAWN, ei.pe->pawns_score());
- Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]);
- if (pos.non_pawn_material() >= SpaceThreshold)
- Trace::add(SPACE, evaluate_space<WHITE>(pos, ei)
- , evaluate_space<BLACK>(pos, ei));
- Trace::add(TOTAL, score);
+ // Main evaluation begins here
+
+ initialize<WHITE>();
+ initialize<BLACK>();
+
+ // Pieces should be evaluated first (populate attack tables)
+ score += pieces<WHITE, KNIGHT>() - pieces<BLACK, KNIGHT>()
+ + pieces<WHITE, BISHOP>() - pieces<BLACK, BISHOP>()
+ + pieces<WHITE, ROOK >() - pieces<BLACK, ROOK >()
+ + pieces<WHITE, QUEEN >() - pieces<BLACK, QUEEN >();
+
+ score += mobility[WHITE] - mobility[BLACK];
+
+ score += king< WHITE>() - king< BLACK>()
+ + threats<WHITE>() - threats<BLACK>()
+ + passed< WHITE>() - passed< BLACK>()
+ + space< WHITE>() - space< BLACK>();
+
+ score += initiative(eg_value(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);
+
+ // In case of tracing add all remaining individual evaluation terms
+ if (T)
+ {
+ Trace::add(MATERIAL, pos.psq_score());
+ Trace::add(IMBALANCE, me->imbalance());
+ Trace::add(PAWN, pe->pawn_score(WHITE), pe->pawn_score(BLACK));
+ Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]);
+ Trace::add(TOTAL, score);
+ }
+
+ return (pos.side_to_move() == WHITE ? v : -v) // Side to move point of view
+ + Eval::Tempo;
}
- return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo; // Side to move point of view
-}
+} // namespace
-// Explicit template instantiations
-template Value Eval::evaluate<true >(const Position&);
-template Value Eval::evaluate<false>(const Position&);
+
+/// evaluate() is the evaluator for the outer world. It returns a static
+/// 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();
+}
/// trace() is like evaluate(), but instead of returning a value, it returns
std::memset(scores, 0, sizeof(scores));
- Value v = evaluate<true>(pos);
- v = pos.side_to_move() == WHITE ? v : -v; // White's point of view
+ pos.this_thread()->contempt = SCORE_ZERO; // Reset any dynamic contempt
+
+ Value v = Evaluation<TRACE>(pos).value();
+
+ v = pos.side_to_move() == WHITE ? v : -v; // Trace scores are from white's point of view
std::stringstream ss;
ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2)
- << " Eval term | White | Black | Total \n"
- << " | MG EG | MG EG | MG EG \n"
- << "----------------+-------------+-------------+-------------\n"
- << " Material | " << Term(MATERIAL)
- << " Imbalance | " << Term(IMBALANCE)
- << " Pawns | " << Term(PAWN)
- << " Knights | " << Term(KNIGHT)
- << " Bishop | " << Term(BISHOP)
- << " Rooks | " << Term(ROOK)
- << " Queens | " << Term(QUEEN)
- << " Mobility | " << Term(MOBILITY)
- << " King safety | " << Term(KING)
- << " Threats | " << Term(THREAT)
- << " Passed pawns | " << Term(PASSED)
- << " Space | " << Term(SPACE)
- << "----------------+-------------+-------------+-------------\n"
- << " Total | " << Term(TOTAL);
-
- ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n";
+ << " Term | White | Black | Total \n"
+ << " | MG EG | MG EG | MG EG \n"
+ << " ------------+-------------+-------------+------------\n"
+ << " Material | " << Term(MATERIAL)
+ << " Imbalance | " << Term(IMBALANCE)
+ << " Initiative | " << Term(INITIATIVE)
+ << " Pawns | " << Term(PAWN)
+ << " Knights | " << Term(KNIGHT)
+ << " Bishops | " << Term(BISHOP)
+ << " Rooks | " << Term(ROOK)
+ << " Queens | " << Term(QUEEN)
+ << " Mobility | " << Term(MOBILITY)
+ << " King safety | " << Term(KING)
+ << " Threats | " << Term(THREAT)
+ << " Passed | " << Term(PASSED)
+ << " Space | " << Term(SPACE)
+ << " ------------+-------------+-------------+------------\n"
+ << " Total | " << Term(TOTAL);
+
+ ss << "\nTotal evaluation: " << to_cp(v) << " (white side)\n";
return ss.str();
}
projects / stockfish / blobdiff