/*
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) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file)
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include "evaluate.h"
+
#include <algorithm>
#include <cassert>
-#include <cstring> // For std::memset
+#include <cmath>
+#include <cstdlib>
+#include <fstream>
#include <iomanip>
+#include <iostream>
#include <sstream>
+#include <vector>
-#include "bitboard.h"
-#include "evaluate.h"
-#include "material.h"
-#include "pawns.h"
+#include "incbin/incbin.h"
+#include "misc.h"
+#include "nnue/evaluate_nnue.h"
+#include "position.h"
#include "thread.h"
-
-namespace Trace {
-
- enum Tracing { NO_TRACE, TRACE };
-
- enum Term { // The first 8 entries are reserved for PieceType
- MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, INITIATIVE, TOTAL, TERM_NB
- };
-
- Score scores[TERM_NB][COLOR_NB];
-
- double to_cp(Value v) { return double(v) / PawnValueEg; }
-
- void add(int idx, Color c, Score s) {
- scores[idx][c] = s;
- }
-
- void add(int idx, Score w, Score b = SCORE_ZERO) {
- scores[idx][WHITE] = w;
- scores[idx][BLACK] = b;
- }
-
- 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;
- }
-
- std::ostream& operator<<(std::ostream& os, Term t) {
-
- if (t == MATERIAL || t == IMBALANCE || t == INITIATIVE || t == TOTAL)
- os << " ---- ----" << " | " << " ---- ----";
- else
- os << scores[t][WHITE] << " | " << scores[t][BLACK];
-
- os << " | " << scores[t][WHITE] - scores[t][BLACK] << "\n";
- return os;
- }
-}
-
-using namespace Trace;
-
-namespace {
-
- 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);
-
- constexpr Bitboard KingFlank[FILE_NB] = {
- QueenSide ^ FileDBB, QueenSide, QueenSide,
- CenterFiles, CenterFiles,
- KingSide, KingSide, KingSide ^ FileEBB
- };
-
- // Threshold for lazy and space evaluation
- constexpr Value LazyThreshold = Value(1500);
- constexpr Value SpaceThreshold = Value(12222);
-
- // KingAttackWeights[PieceType] contains king attack weights by piece type
- constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 77, 55, 44, 10 };
-
- // Penalties for enemy's safe checks
- constexpr int QueenSafeCheck = 780;
- constexpr int RookSafeCheck = 880;
- constexpr int BishopSafeCheck = 435;
- constexpr int KnightSafeCheck = 790;
-
-#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.
- constexpr Score MobilityBonus[][32] = {
- { S(-62,-81), S(-53,-56), S(-12,-30), S( -4,-14), S( 3, 8), S( 13, 15), // Knights
- 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), // Bishops
- 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.
- 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.
- constexpr Score RookOnFile[] = { S(18, 7), S(44, 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.
- constexpr Score ThreatByMinor[PIECE_TYPE_NB] = {
- S(0, 0), S(0, 31), S(39, 42), S(57, 44), S(68, 112), S(62, 120)
- };
-
- constexpr Score ThreatByRook[PIECE_TYPE_NB] = {
- S(0, 0), S(0, 24), S(38, 71), S(38, 61), S(0, 38), S(51, 38)
- };
-
- // 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
- 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)
- };
-
- // Assorted bonuses and penalties
- constexpr Score BishopPawns = S( 3, 7);
- constexpr Score CloseEnemies = S( 8, 0);
- constexpr Score CorneredBishop = S( 50, 50);
- constexpr Score Hanging = S( 69, 36);
- constexpr Score KingProtector = S( 7, 8);
- constexpr Score KnightOnQueen = S( 16, 12);
- constexpr Score LongDiagonalBishop = S( 45, 0);
- constexpr Score MinorBehindPawn = S( 18, 3);
- constexpr Score PawnlessFlank = S( 17, 95);
- constexpr Score RestrictedPiece = S( 7, 7);
- constexpr Score RookOnPawn = S( 10, 32);
- constexpr Score SliderOnQueen = S( 59, 18);
- constexpr Score ThreatByKing = S( 24, 89);
- constexpr Score ThreatByPawnPush = S( 48, 39);
- constexpr Score ThreatByRank = S( 13, 0);
- constexpr Score ThreatBySafePawn = S(173, 94);
- constexpr Score TrappedRook = S( 96, 4);
- constexpr Score WeakQueen = S( 49, 15);
- constexpr Score WeakUnopposedPawn = S( 12, 23);
-
-#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 };
-
- // 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];
-
- // 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] 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.
- 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];
- };
-
-
- // 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() {
-
- 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 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 queen, or controlled by enemy pawns
- // are excluded from the mobility area.
- mobilityArea[Us] = ~(b | pos.pieces(Us, KING, QUEEN) | pe->pawn_attacks(Them));
-
- // 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
- kingRing[Us] = attackedBy[Us][KING];
- if (relative_rank(Us, pos.square<KING>(Us)) == RANK_1)
- kingRing[Us] |= shift<Up>(kingRing[Us]);
-
- if (file_of(pos.square<KING>(Us)) == FILE_H)
- kingRing[Us] |= shift<WEST>(kingRing[Us]);
-
- 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));
- kingRing[Us] &= ~double_pawn_attacks_bb<Us>(pos.pieces(Us, PAWN));
- kingAttacksCount[Them] = kingAttackersWeight[Them] = 0;
- }
-
-
- // Evaluation::pieces() scores pieces of a given color and type
- template<Tracing T> template<Color Us, PieceType Pt>
- Score Evaluation<T>::pieces() {
-
- 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;
-
- 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(QUEEN))
- : Pt == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(QUEEN) ^ pos.pieces(Us, ROOK))
- : pos.attacks_from<Pt>(s);
-
- if (pos.blockers_for_king(Us) & s)
- b &= LineBB[pos.square<KING>(Us)][s];
-
- attackedBy2[Us] |= attackedBy[Us][ALL_PIECES] & b;
- attackedBy[Us][Pt] |= b;
- attackedBy[Us][ALL_PIECES] |= b;
-
- if (b & kingRing[Them])
+#include "types.h"
+#include "uci.h"
+
+// Macro to embed the default efficiently updatable neural network (NNUE) file
+// data in the engine binary (using incbin.h, by Dale Weiler).
+// This macro invocation will declare the following three variables
+// const unsigned char gEmbeddedNNUEData[]; // a pointer to the embedded data
+// const unsigned char *const gEmbeddedNNUEEnd; // a marker to the end
+// const unsigned int gEmbeddedNNUESize; // the size of the embedded file
+// Note that this does not work in Microsoft Visual Studio.
+#if !defined(_MSC_VER) && !defined(NNUE_EMBEDDING_OFF)
+INCBIN(EmbeddedNNUE, EvalFileDefaultName);
+#else
+const unsigned char gEmbeddedNNUEData[1] = {0x0};
+const unsigned char* const gEmbeddedNNUEEnd = &gEmbeddedNNUEData[1];
+const unsigned int gEmbeddedNNUESize = 1;
+#endif
+
+
+namespace Stockfish {
+
+namespace Eval {
+
+std::string currentEvalFileName = "None";
+
+// Tries to load a NNUE network at startup time, or when the engine
+// receives a UCI command "setoption name EvalFile value nn-[a-z0-9]{12}.nnue"
+// The name of the NNUE network is always retrieved from the EvalFile option.
+// We search the given network in three locations: internally (the default
+// network may be embedded in the binary), in the active working directory and
+// in the engine directory. Distro packagers may define the DEFAULT_NNUE_DIRECTORY
+// variable to have the engine search in a special directory in their distro.
+void NNUE::init() {
+
+ std::string eval_file = std::string(Options["EvalFile"]);
+ if (eval_file.empty())
+ eval_file = EvalFileDefaultName;
+
+#if defined(DEFAULT_NNUE_DIRECTORY)
+ std::vector<std::string> dirs = {"<internal>", "", CommandLine::binaryDirectory,
+ stringify(DEFAULT_NNUE_DIRECTORY)};
+#else
+ std::vector<std::string> dirs = {"<internal>", "", CommandLine::binaryDirectory};
+#endif
+
+ for (const std::string& directory : dirs)
+ if (currentEvalFileName != eval_file)
{
- kingAttackersCount[Us]++;
- kingAttackersWeight[Us] += KingAttackWeights[Pt];
- kingAttacksCount[Us] += popcount(b & attackedBy[Them][KING]);
- }
-
- int mob = popcount(b & mobilityArea[Us]);
-
- mobility[Us] += MobilityBonus[Pt - 2][mob];
-
- if (Pt == BISHOP || Pt == KNIGHT)
- {
- // 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][bool(attackedBy[Us][PAWN] & s)] * 2;
-
- 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 if the piece is far from the king
- score -= KingProtector * distance(s, pos.square<KING>(Us));
-
- if (Pt == BISHOP)
- {
- // 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(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 ( Pt == BISHOP
- && pos.is_chess960()
- && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
+ if (directory != "<internal>")
{
- 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;
+ std::ifstream stream(directory + eval_file, std::ios::binary);
+ if (NNUE::load_eval(eval_file, stream))
+ currentEvalFileName = eval_file;
}
- }
-
- if (Pt == ROOK)
- {
- // 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 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)
+ if (directory == "<internal>" && eval_file == EvalFileDefaultName)
{
- 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.castling_rights(Us));
+ // C++ way to prepare a buffer for a memory stream
+ class MemoryBuffer: public std::basic_streambuf<char> {
+ public:
+ MemoryBuffer(char* p, size_t n) {
+ setg(p, p, p + n);
+ setp(p, p + n);
+ }
+ };
+
+ MemoryBuffer buffer(
+ const_cast<char*>(reinterpret_cast<const char*>(gEmbeddedNNUEData)),
+ size_t(gEmbeddedNNUESize));
+ (void) gEmbeddedNNUEEnd; // Silence warning on unused variable
+
+ std::istream stream(&buffer);
+ if (NNUE::load_eval(eval_file, stream))
+ currentEvalFileName = eval_file;
}
}
+}
- if (Pt == QUEEN)
- {
- // Penalty if any relative pin or discovered attack against the queen
- Bitboard queenPinners;
- if (pos.slider_blockers(pos.pieces(Them, ROOK, BISHOP), s, queenPinners))
- score -= WeakQueen;
- }
- }
- if (T)
- Trace::add(Pt, Us, score);
-
- return score;
- }
-
-
- // Evaluation::king() assigns bonuses and penalties to a king of a given color
- template<Tracing T> template<Color Us>
- Score Evaluation<T>::king() const {
-
- 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 kingFlank, weak, b, b1, b2, safe, unsafeChecks;
-
- // King shelter and enemy pawns storm
- Score score = pe->king_safety<Us>(pos);
-
- // Find the squares that opponent attacks in our king flank, and the squares
- // which are attacked twice in that flank.
- kingFlank = KingFlank[file_of(ksq)];
- b1 = attackedBy[Them][ALL_PIECES] & kingFlank & Camp;
- b2 = b1 & attackedBy2[Them];
-
- int tropism = popcount(b1) + popcount(b2);
-
- // Main king safety evaluation
- 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 &= ~attackedBy[Us][ALL_PIECES] | (weak & attackedBy2[Them]);
-
- 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) & 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 += 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)
- + 150 * popcount(pos.blockers_for_king(Us) | unsafeChecks)
- + tropism * tropism / 4
- - 873 * !pos.count<QUEEN>(Them)
- - 6 * mg_value(score) / 8
- + mg_value(mobility[Them] - mobility[Us])
- - 30;
-
- // Transform the kingDanger units into a Score, and subtract it from the evaluation
- if (kingDanger > 0)
- score -= make_score(kingDanger * kingDanger / 4096, kingDanger / 16);
-
- // Penalty when our king is on a pawnless flank
- if (!(pos.pieces(PAWN) & kingFlank))
- score -= PawnlessFlank;
-
- // King tropism bonus, to anticipate slow motion attacks on our king
- score -= CloseEnemies * tropism;
-
- if (T)
- Trace::add(KING, Us, score);
-
- return score;
- }
-
-
- // 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 {
-
- 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, nonPawnEnemies, stronglyProtected, safe, restricted;
- Score score = SCORE_ZERO;
-
- // 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.
- stronglyProtected = attackedBy[Them][PAWN]
- | (attackedBy2[Them] & ~attackedBy2[Us]);
-
- // Non-pawn enemies, strongly protected
- defended = nonPawnEnemies & stronglyProtected;
-
- // Enemies not strongly protected and under our attack
- weak = pos.pieces(Them) & ~stronglyProtected & attackedBy[Us][ALL_PIECES];
-
- // Safe or protected squares
- safe = ~attackedBy[Them][ALL_PIECES] | attackedBy[Us][ALL_PIECES];
-
- // Bonus according to the kind of attacking pieces
- if (defended | weak)
- {
- 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);
- }
-
- 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);
- }
-
- if (weak & attackedBy[Us][KING])
- score += ThreatByKing;
-
- b = ~attackedBy[Them][ALL_PIECES]
- | (nonPawnEnemies & attackedBy2[Us]);
- score += Hanging * popcount(weak & b);
- }
-
- // Bonus for restricting their piece moves
- restricted = attackedBy[Them][ALL_PIECES]
- & ~stronglyProtected
- & attackedBy[Us][ALL_PIECES];
- score += RestrictedPiece * popcount(restricted);
-
- // Bonus for enemy unopposed weak pawns
- if (pos.pieces(Us, ROOK, QUEEN))
- score += WeakUnopposedPawn * pe->weak_unopposed(Them);
-
- // 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 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);
-
- // Our safe or protected pawns
- b = pos.pieces(Us, PAWN) & safe;
+// Verifies that the last net used was loaded successfully
+void NNUE::verify() {
- b = pawn_attacks_bb<Us>(b) & nonPawnEnemies;
- score += ThreatBySafePawn * popcount(b);
+ std::string eval_file = std::string(Options["EvalFile"]);
+ if (eval_file.empty())
+ eval_file = EvalFileDefaultName;
- // Bonus for threats on the next moves against enemy queen
- if (pos.count<QUEEN>(Them) == 1)
+ if (currentEvalFileName != eval_file)
{
- 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]);
+ std::string msg1 =
+ "Network evaluation parameters compatible with the engine must be available.";
+ std::string msg2 = "The network file " + eval_file + " was not loaded successfully.";
+ std::string msg3 = "The UCI option EvalFile might need to specify the full path, "
+ "including the directory name, to the network file.";
+ std::string msg4 = "The default net can be downloaded from: "
+ "https://tests.stockfishchess.org/api/nn/"
+ + std::string(EvalFileDefaultName);
+ std::string msg5 = "The engine will be terminated now.";
+
+ sync_cout << "info string ERROR: " << msg1 << sync_endl;
+ sync_cout << "info string ERROR: " << msg2 << sync_endl;
+ sync_cout << "info string ERROR: " << msg3 << sync_endl;
+ sync_cout << "info string ERROR: " << msg4 << sync_endl;
+ sync_cout << "info string ERROR: " << msg5 << sync_endl;
+
+ exit(EXIT_FAILURE);
}
- if (T)
- Trace::add(THREAT, Us, score);
-
- return score;
- }
-
- // Evaluation::passed() evaluates the passed pawns and candidate passed
- // pawns of the given color.
-
- 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);
-
- 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 = pe->passed_pawns(Us);
-
- while (b)
- {
- Square s = pop_lsb(&b);
-
- assert(!(pos.pieces(Them, PAWN) & forward_file_bb(Us, s + Up)));
-
- int r = relative_rank(Us, s);
-
- Score bonus = PassedRank[r];
-
- if (r > RANK_3)
- {
- int w = (r-2) * (r-2) + 2;
- 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);
-
- // If blockSq is not the queening square then consider also a second push
- 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_file_bb(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];
-
- 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;
-
- // 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;
-
- else if (defendedSquares & blockSq)
- k += 4;
-
- bonus += make_score(k * w, k * w);
- }
- } // rank > 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)];
- }
-
- if (T)
- Trace::add(PASSED, Us, score);
-
- return score;
- }
-
-
- // 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<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 Direction Down = (Us == WHITE ? SOUTH : NORTH);
- 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];
-
- // Find all squares which are at most three squares behind some friendly pawn
- Bitboard behind = pos.pieces(Us, PAWN);
- behind |= shift<Down>(behind);
- behind |= shift<Down>(shift<Down>(behind));
-
- int bonus = popcount(safe) + popcount(behind & safe);
- int weight = pos.count<ALL_PIECES>(Us)
- - 2 * popcount(pe->semiopenFiles[WHITE] & pe->semiopenFiles[BLACK]);
-
- Score score = make_score(bonus * weight * weight / 16, 0);
-
- if (T)
- Trace::add(SPACE, Us, score);
-
- return score;
- }
-
-
- // 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 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 complexity = 9 * pe->pawn_asymmetry()
- + 11 * pos.count<PAWN>()
- + 9 * outflanking
- + 18 * pawnsOnBothFlanks
- + 49 * !pos.non_pawn_material()
- -121 ;
-
- // 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 v = ((eg > 0) - (eg < 0)) * std::max(complexity, -abs(eg));
-
- if (T)
- Trace::add(INITIATIVE, make_score(0, v));
-
- return make_score(0, v);
- }
-
-
- // 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;
- int sf = me->scale_factor(pos, strongSide);
-
- // If scale is not already specific, scale down the endgame via general heuristics
- if (sf == SCALE_FACTOR_NORMAL)
- {
- if ( pos.opposite_bishops()
- && pos.non_pawn_material(WHITE) == BishopValueMg
- && pos.non_pawn_material(BLACK) == BishopValueMg)
- sf = 8 + 4 * pe->pawn_asymmetry();
- else
- sf = std::min(40 + (pos.opposite_bishops() ? 2 : 7) * pos.count<PAWN>(strongSide), sf);
-
- }
+ sync_cout << "info string NNUE evaluation using " << eval_file << sync_endl;
+}
+}
- return ScaleFactor(sf);
- }
+// Returns a static, purely materialistic evaluation of the position from
+// the point of view of the given color. It can be divided by PawnValue to get
+// an approximation of the material advantage on the board in terms of pawns.
+Value Eval::simple_eval(const Position& pos, Color c) {
+ return PawnValue * (pos.count<PAWN>(c) - pos.count<PAWN>(~c))
+ + (pos.non_pawn_material(c) - pos.non_pawn_material(~c));
+}
- // 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.
- template<Tracing T>
- Value Evaluation<T>::value() {
+// 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) {
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;
-
- // Main evaluation begins here
-
- initialize<WHITE>();
- initialize<BLACK>();
+ Value v;
+ Color stm = pos.side_to_move();
+ int shuffling = pos.rule50_count();
+ int simpleEval = simple_eval(pos, stm) + (int(pos.key() & 7) - 3);
- // 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 >();
+ bool lazy = std::abs(simpleEval) >= RookValue + KnightValue + 16 * shuffling * shuffling
+ + std::abs(pos.this_thread()->bestValue)
+ + std::abs(pos.this_thread()->rootSimpleEval);
- 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));
+ if (lazy)
+ v = Value(simpleEval);
+ else
+ {
+ int nnueComplexity;
+ Value nnue = NNUE::evaluate(pos, true, &nnueComplexity);
- // 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;
+ Value optimism = pos.this_thread()->optimism[stm];
- v /= int(PHASE_MIDGAME);
+ // Blend optimism and eval with nnue complexity and material imbalance
+ optimism += optimism * (nnueComplexity + std::abs(simpleEval - nnue)) / 512;
+ nnue -= nnue * (nnueComplexity + std::abs(simpleEval - nnue)) / 32768;
- // 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);
+ int npm = pos.non_pawn_material() / 64;
+ v = (nnue * (915 + npm + 9 * pos.count<PAWN>()) + optimism * (154 + npm)) / 1024;
}
- return (pos.side_to_move() == WHITE ? v : -v) // Side to move point of view
- + Eval::Tempo;
- }
-
-} // namespace
+ // Damp down the evaluation linearly when shuffling
+ v = v * (200 - shuffling) / 214;
+ // Guarantee evaluation does not hit the tablebase range
+ v = std::clamp(v, VALUE_TB_LOSS_IN_MAX_PLY + 1, VALUE_TB_WIN_IN_MAX_PLY - 1);
-/// 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();
+ return v;
}
+// Like evaluate(), but instead of returning a value, it returns
+// a string (suitable for outputting to stdout) that contains the detailed
+// descriptions and values of each evaluation term. Useful for debugging.
+// Trace scores are from white's point of view
+std::string Eval::trace(Position& pos) {
-/// trace() is like evaluate(), but instead of returning a value, it returns
-/// a string (suitable for outputting to stdout) that contains the detailed
-/// descriptions and values of each evaluation term. Useful for debugging.
-
-std::string Eval::trace(const Position& pos) {
+ if (pos.checkers())
+ return "Final evaluation: none (in check)";
- std::memset(scores, 0, sizeof(scores));
+ // Reset any global variable used in eval
+ pos.this_thread()->bestValue = VALUE_ZERO;
+ pos.this_thread()->rootSimpleEval = VALUE_ZERO;
+ pos.this_thread()->optimism[WHITE] = VALUE_ZERO;
+ pos.this_thread()->optimism[BLACK] = VALUE_ZERO;
- pos.this_thread()->contempt = SCORE_ZERO; // Reset any dynamic contempt
+ std::stringstream ss;
+ ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2);
+ ss << '\n' << NNUE::trace(pos) << '\n';
- Value v = Evaluation<TRACE>(pos).value();
+ ss << std::showpoint << std::showpos << std::fixed << std::setprecision(2) << std::setw(15);
- v = pos.side_to_move() == WHITE ? v : -v; // Trace scores are from white's point of view
+ Value v;
+ v = NNUE::evaluate(pos, false);
+ v = pos.side_to_move() == WHITE ? v : -v;
+ ss << "NNUE evaluation " << 0.01 * UCI::to_cp(v) << " (white side)\n";
- std::stringstream ss;
- ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2)
- << " 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);
+ v = evaluate(pos);
+ v = pos.side_to_move() == WHITE ? v : -v;
+ ss << "Final evaluation " << 0.01 * UCI::to_cp(v) << " (white side)";
+ ss << " [with scaled NNUE, ...]";
+ ss << "\n";
- ss << "\nTotal evaluation: " << to_cp(v) << " (white side)\n";
-
- return ss.str();
+ return ss.str();
}
+
+} // namespace Stockfish