From 5f1843c9cb55afcd3fb1da9e9dc4b0092f25d9f0 Mon Sep 17 00:00:00 2001 From: Joost VandeVondele Date: Sat, 11 Jul 2020 16:59:33 +0200 Subject: [PATCH] Small trivial cleanups closes https://github.com/official-stockfish/Stockfish/pull/2801 No functional change --- README.md | 53 +++++++++++++++++++++++++----------------------- src/Makefile | 2 +- src/bitboard.cpp | 12 ++++++++++- src/bitboard.h | 10 --------- src/evaluate.cpp | 17 ++++++++-------- src/material.cpp | 2 +- src/misc.cpp | 17 ++++++++-------- src/misc.h | 8 -------- src/movegen.cpp | 2 +- src/movepick.cpp | 14 ++++++------- src/movepick.h | 8 ++++---- src/pawns.cpp | 2 +- src/position.cpp | 4 ++-- src/position.h | 5 +++++ src/search.cpp | 15 +++++++------- src/timeman.cpp | 18 ++++++++-------- src/uci.cpp | 2 +- 17 files changed, 96 insertions(+), 95 deletions(-) diff --git a/README.md b/README.md index 7b6ddf4c..2cc88bf4 100644 --- a/README.md +++ b/README.md @@ -4,17 +4,17 @@ [![Build Status](https://ci.appveyor.com/api/projects/status/github/official-stockfish/Stockfish?branch=master&svg=true)](https://ci.appveyor.com/project/mcostalba/stockfish/branch/master) [Stockfish](https://stockfishchess.org) is a free, powerful UCI chess engine -derived from Glaurung 2.1. It features two evaluation functions, the classical -evaluation based on handcrafted terms, and the NNUE evaluation based on -efficiently updateable neural networks. The classical evaluation runs efficiently -on most 64bit CPU architectures, while the NNUE evaluation benefits strongly from the -vector intrinsics available on modern CPUs (avx2 or similar). +derived from Glaurung 2.1. Stockfish is not a complete chess program and requires a +UCI-compatible graphical user interface (GUI) (e.g. XBoard with PolyGlot, Scid, +Cute Chess, eboard, Arena, Sigma Chess, Shredder, Chess Partner or Fritz) in order +to be used comfortably. Read the documentation for your GUI of choice for information +about how to use Stockfish with it. -Stockfish is not a complete chess program and requires a -UCI-compatible GUI (e.g. XBoard with PolyGlot, Scid, Cute Chess, eboard, Arena, -Sigma Chess, Shredder, Chess Partner or Fritz) in order to be used comfortably. -Read the documentation for your GUI of choice for information about how to use -Stockfish with it. +The Stockfish engine features two evaluation functions for chess, the classical +evaluation based on handcrafted terms, and the NNUE evaluation based on efficiently +updateable neural networks. The classical evaluation runs efficiently on most 64bit +CPU architectures, while the NNUE evaluation benefits strongly from the vector +intrinsics available on modern CPUs (avx2 or similar). ## Files @@ -28,10 +28,13 @@ This distribution of Stockfish consists of the following files: * src, a subdirectory containing the full source code, including a Makefile that can be used to compile Stockfish on Unix-like systems. -To use the NNUE evaluation an additional data file with neural network parameters -needs to be downloaded. The filename for the default set can be found as the default -value of the `EvalFile` UCI option, with the format -`nn-[SHA256 first 12 digits].nnue` (e.g. nn-c157e0a5755b.nnue). This file can be downloaded from + * a file with the .nnue extension, storing the neural network for the NNUE + evaluation. + +Note: to use the NNUE evaluation, the additional data file with neural network parameters +needs to be downloaded. The filename for the default net can be found as the default +value of the `EvalFile` UCI option, with the format `nn-[SHA256 first 12 digits].nnue` +(for instance, `nn-c157e0a5755b.nnue`). This file can be downloaded from ``` https://tests.stockfishchess.org/api/nn/[filename] ``` @@ -64,14 +67,6 @@ Currently, Stockfish has the following UCI options: The name of the file of the NNUE evaluation parameters. Depending on the GUI the filename should include the full path to the folder/directory that contains the file. - * #### Contempt - A positive value for contempt favors middle game positions and avoids draws, - effective for the classical evaluation only. - - * #### Analysis Contempt - By default, contempt is set to prefer the side to move. Set this option to "White" - or "Black" to analyse with contempt for that side, or "Off" to disable contempt. - * #### UCI_AnalyseMode An option handled by your GUI. @@ -120,6 +115,14 @@ Currently, Stockfish has the following UCI options: Limit Syzygy tablebase probing to positions with at most this many pieces left (including kings and pawns). + * #### Contempt + A positive value for contempt favors middle game positions and avoids draws, + effective for the classical evaluation only. + + * #### Analysis Contempt + By default, contempt is set to prefer the side to move. Set this option to "White" + or "Black" to analyse with contempt for that side, or "Off" to disable contempt. + * #### Move Overhead Assume a time delay of x ms due to network and GUI overheads. This is useful to avoid losses on time in those cases. @@ -138,7 +141,7 @@ Currently, Stockfish has the following UCI options: * #### Debug Log File Write all communication to and from the engine into a text file. -## Classical and NNUE evaluation +## A note on classical and NNUE evaluation Both approaches assign a value to a position that is used in alpha-beta (PVS) search to find the best move. The classical evaluation computes this value as a function @@ -226,6 +229,7 @@ targets with corresponding descriptions. cd src make help make build ARCH=x86-64-modern + make net ``` When not using the Makefile to compile (for instance with Microsoft MSVC) you @@ -237,8 +241,7 @@ compiler you used to create your executable. These informations can be found by typing the following commands in a console: ``` - ./stockfish - compiler + ./stockfish compiler ``` ## Understanding the code base and participating in the project diff --git a/src/Makefile b/src/Makefile index b0274504..74ef87b9 100644 --- a/src/Makefile +++ b/src/Makefile @@ -370,7 +370,7 @@ else endif endif -ifeq ($(KERNEL),Darwin) +ifeq ($(KERNEL),Darwin) CXXFLAGS += -arch $(arch) -mmacosx-version-min=10.14 LDFLAGS += -arch $(arch) -mmacosx-version-min=10.14 XCRUN = xcrun diff --git a/src/bitboard.cpp b/src/bitboard.cpp index f531010c..80206b58 100644 --- a/src/bitboard.cpp +++ b/src/bitboard.cpp @@ -39,6 +39,16 @@ namespace { Bitboard BishopTable[0x1480]; // To store bishop attacks void init_magics(PieceType pt, Bitboard table[], Magic magics[]); + +} + + +/// safe_destination() returns the bitboard of target square for the given step +/// from the given square. If the step is off the board, returns empty bitboard. + +inline Bitboard safe_destination(Square s, int step) { + Square to = Square(s + step); + return is_ok(to) && distance(s, to) <= 2 ? square_bb(to) : Bitboard(0); } @@ -110,7 +120,7 @@ namespace { Direction RookDirections[4] = {NORTH, SOUTH, EAST, WEST}; Direction BishopDirections[4] = {NORTH_EAST, SOUTH_EAST, SOUTH_WEST, NORTH_WEST}; - for(Direction d : (pt == ROOK ? RookDirections : BishopDirections)) + for (Direction d : (pt == ROOK ? RookDirections : BishopDirections)) { Square s = sq; while(safe_destination(s, d) && !(occupied & s)) diff --git a/src/bitboard.h b/src/bitboard.h index a899d879..29d8f66d 100644 --- a/src/bitboard.h +++ b/src/bitboard.h @@ -279,16 +279,6 @@ inline int edge_distance(File f) { return std::min(f, File(FILE_H - f)); } inline int edge_distance(Rank r) { return std::min(r, Rank(RANK_8 - r)); } -/// safe_destination() returns the bitboard of target square for the given step -/// from the given square. If the step is off the board, returns empty bitboard. - -inline Bitboard safe_destination(Square s, int step) -{ - Square to = Square(s + step); - return is_ok(to) && distance(s, to) <= 2 ? square_bb(to) : Bitboard(0); -} - - /// attacks_bb(Square) returns the pseudo attacks of the give piece type /// assuming an empty board. diff --git a/src/evaluate.cpp b/src/evaluate.cpp index c66938d6..ce92db9a 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -288,8 +288,8 @@ namespace { attackedBy2[Us] = dblAttackByPawn | (attackedBy[Us][KING] & attackedBy[Us][PAWN]); // Init our king safety tables - Square s = make_square(Utility::clamp(file_of(ksq), FILE_B, FILE_G), - Utility::clamp(rank_of(ksq), RANK_2, RANK_7)); + Square s = make_square(std::clamp(file_of(ksq), FILE_B, FILE_G), + std::clamp(rank_of(ksq), RANK_2, RANK_7)); kingRing[Us] = attacks_bb(s) | s; kingAttackersCount[Them] = popcount(kingRing[Us] & pe->pawn_attacks(Them)); @@ -686,8 +686,8 @@ namespace { Square blockSq = s + Up; // Adjust bonus based on the king's proximity - bonus += make_score(0, ( (king_proximity(Them, blockSq) * 19) / 4 - - king_proximity(Us, blockSq) * 2) * w); + bonus += make_score(0, ( king_proximity(Them, blockSq) * 19 / 4 + - king_proximity(Us, blockSq) * 2) * w); // If blockSq is not the queening square then consider also a second push if (r != RANK_7) @@ -731,7 +731,7 @@ namespace { // Evaluation::space() computes a space evaluation for a given side, aiming to improve game - // play in the opening. It is based on the number of safe squares on the 4 central files + // play in the opening. It is based on the number of safe squares on the four central files // on ranks 2 to 4. Completely safe squares behind a friendly pawn are counted twice. // Finally, the space bonus is multiplied by a weight which decreases according to occupancy. @@ -804,7 +804,7 @@ namespace { // Now apply the bonus: note that we find the attacking side by extracting the // sign of the midgame or endgame values, and that we carefully cap the bonus // so that the midgame and endgame scores do not change sign after the bonus. - int u = ((mg > 0) - (mg < 0)) * Utility::clamp(complexity + 50, -abs(mg), 0); + int u = ((mg > 0) - (mg < 0)) * std::clamp(complexity + 50, -abs(mg), 0); int v = ((eg > 0) - (eg < 0)) * std::max(complexity, -abs(eg)); mg += u; @@ -951,8 +951,8 @@ Value Eval::evaluate(const Position& pos) { // Damp down the evaluation linearly when shuffling v = v * (100 - pos.rule50_count()) / 100; - // Guarantee evalution outside of TB range - v = Utility::clamp(v, VALUE_TB_LOSS_IN_MAX_PLY + 1, VALUE_TB_WIN_IN_MAX_PLY - 1); + // 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); return v; } @@ -1013,6 +1013,5 @@ std::string Eval::trace(const Position& pos) { v = pos.side_to_move() == WHITE ? v : -v; ss << "\nFinal evaluation: " << to_cp(v) << " (white side)\n"; - return ss.str(); } diff --git a/src/material.cpp b/src/material.cpp index 0ef9926f..870a5e11 100644 --- a/src/material.cpp +++ b/src/material.cpp @@ -130,7 +130,7 @@ Entry* probe(const Position& pos) { Value npm_w = pos.non_pawn_material(WHITE); Value npm_b = pos.non_pawn_material(BLACK); - Value npm = Utility::clamp(npm_w + npm_b, EndgameLimit, MidgameLimit); + Value npm = std::clamp(npm_w + npm_b, EndgameLimit, MidgameLimit); // Map total non-pawn material into [PHASE_ENDGAME, PHASE_MIDGAME] e->gamePhase = Phase(((npm - EndgameLimit) * PHASE_MIDGAME) / (MidgameLimit - EndgameLimit)); diff --git a/src/misc.cpp b/src/misc.cpp index 56a3dcad..80c436ac 100644 --- a/src/misc.cpp +++ b/src/misc.cpp @@ -328,16 +328,16 @@ void prefetch(void* addr) { #endif -/// Wrappers for systems where the c++17 implementation doesn't guarantee the availability of aligned_alloc. -/// Memory allocated with std_aligned_alloc must be freed with std_aligned_free. -/// + +/// std_aligned_alloc() is our wrapper for systems where the c++17 implementation +/// does not guarantee the availability of aligned_alloc(). Memory allocated with +/// std_aligned_alloc() must be freed with std_aligned_free(). void* std_aligned_alloc(size_t alignment, size_t size) { + #if defined(POSIXALIGNEDALLOC) - void *pointer; - if(posix_memalign(&pointer, alignment, size) == 0) - return pointer; - return nullptr; + void *mem; + return posix_memalign(&mem, alignment, size) ? nullptr : mem; #elif defined(_WIN32) return _mm_malloc(size, alignment); #else @@ -346,6 +346,7 @@ void* std_aligned_alloc(size_t alignment, size_t size) { } void std_aligned_free(void* ptr) { + #if defined(POSIXALIGNEDALLOC) free(ptr); #elif defined(_WIN32) @@ -355,7 +356,7 @@ void std_aligned_free(void* ptr) { #endif } -/// aligned_ttmem_alloc() will return suitably aligned memory, and if possible use large pages. +/// aligned_ttmem_alloc() will return suitably aligned memory, if possible using large pages. /// The returned pointer is the aligned one, while the mem argument is the one that needs /// to be passed to free. With c++17 some of this functionality could be simplified. diff --git a/src/misc.h b/src/misc.h index eb4e05c0..8ad17b50 100644 --- a/src/misc.h +++ b/src/misc.h @@ -65,14 +65,6 @@ std::ostream& operator<<(std::ostream&, SyncCout); #define sync_cout std::cout << IO_LOCK #define sync_endl std::endl << IO_UNLOCK -namespace Utility { - -/// Clamp a value between lo and hi. Available in c++17. -template constexpr const T& clamp(const T& v, const T& lo, const T& hi) { - return v < lo ? lo : v > hi ? hi : v; -} - -} /// xorshift64star Pseudo-Random Number Generator /// This class is based on original code written and dedicated diff --git a/src/movegen.cpp b/src/movegen.cpp index d74df4c3..3340f65c 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -248,7 +248,7 @@ namespace { *moveList++ = make_move(ksq, pop_lsb(&b)); if ((Type != CAPTURES) && pos.can_castle(Us & ANY_CASTLING)) - for(CastlingRights cr : { Us & KING_SIDE, Us & QUEEN_SIDE } ) + for (CastlingRights cr : { Us & KING_SIDE, Us & QUEEN_SIDE } ) if (!pos.castling_impeded(cr) && pos.can_castle(cr)) *moveList++ = make(ksq, pos.castling_rook_square(cr)); } diff --git a/src/movepick.cpp b/src/movepick.cpp index 96a44449..153d323e 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -182,7 +182,7 @@ top: --endMoves; ++stage; - /* fallthrough */ + [[fallthrough]]; case REFUTATION: if (select([&](){ return *cur != MOVE_NONE @@ -190,7 +190,7 @@ top: && pos.pseudo_legal(*cur); })) return *(cur - 1); ++stage; - /* fallthrough */ + [[fallthrough]]; case QUIET_INIT: if (!skipQuiets) @@ -203,7 +203,7 @@ top: } ++stage; - /* fallthrough */ + [[fallthrough]]; case QUIET: if ( !skipQuiets @@ -217,7 +217,7 @@ top: endMoves = endBadCaptures; ++stage; - /* fallthrough */ + [[fallthrough]]; case BAD_CAPTURE: return select([](){ return true; }); @@ -228,7 +228,7 @@ top: score(); ++stage; - /* fallthrough */ + [[fallthrough]]; case EVASION: return select([](){ return true; }); @@ -246,14 +246,14 @@ top: return MOVE_NONE; ++stage; - /* fallthrough */ + [[fallthrough]]; case QCHECK_INIT: cur = moves; endMoves = generate(pos, cur); ++stage; - /* fallthrough */ + [[fallthrough]]; case QCHECK: return select([](){ return true; }); diff --git a/src/movepick.h b/src/movepick.h index f080935a..97ea5bec 100644 --- a/src/movepick.h +++ b/src/movepick.h @@ -86,14 +86,14 @@ enum StatsType { NoCaptures, Captures }; /// the move's from and to squares, see www.chessprogramming.org/Butterfly_Boards typedef Stats ButterflyHistory; -/// At higher depths LowPlyHistory records successful quiet moves near the root and quiet -/// moves which are/were in the PV (ttPv) -/// It is cleared with each new search and filled during iterative deepening +/// At higher depths LowPlyHistory records successful quiet moves near the root +/// and quiet moves which are/were in the PV (ttPv). It is cleared with each new +/// search and filled during iterative deepening. constexpr int MAX_LPH = 4; typedef Stats LowPlyHistory; /// CounterMoveHistory stores counter moves indexed by [piece][to] of the previous -/// move, see www.chessprogramming.org/Countermove_Heuristic +/// move, see www.chessprogramming.org/Countermove_Heuristic typedef Stats CounterMoveHistory; /// CapturePieceToHistory is addressed by a move's [piece][to][captured piece type] diff --git a/src/pawns.cpp b/src/pawns.cpp index 868d0c8e..af0f6618 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -219,7 +219,7 @@ Score Entry::evaluate_shelter(const Position& pos, Square ksq) const { Score bonus = make_score(5, 5); - File center = Utility::clamp(file_of(ksq), FILE_B, FILE_G); + File center = std::clamp(file_of(ksq), FILE_B, FILE_G); for (File f = File(center - 1); f <= File(center + 1); ++f) { b = ourPawns & file_bb(f); diff --git a/src/position.cpp b/src/position.cpp index 46e5d78b..02898547 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -1145,8 +1145,8 @@ bool Position::see_ge(Move m, Value threshold) const { // Don't allow pinned pieces to attack (except the king) as long as // there are pinners on their original square. - if (st->pinners[~stm] & occupied) - stmAttackers &= ~st->blockersForKing[stm]; + if (pinners(~stm) & occupied) + stmAttackers &= ~blockers_for_king(stm); if (!stmAttackers) break; diff --git a/src/position.h b/src/position.h index a77050eb..5ce17277 100644 --- a/src/position.h +++ b/src/position.h @@ -113,6 +113,7 @@ public: Bitboard checkers() const; Bitboard blockers_for_king(Color c) const; Bitboard check_squares(PieceType pt) const; + Bitboard pinners(Color c) const; bool is_discovery_check_on_king(Color c, Move m) const; // Attacks to/from a given square @@ -309,6 +310,10 @@ inline Bitboard Position::blockers_for_king(Color c) const { return st->blockersForKing[c]; } +inline Bitboard Position::pinners(Color c) const { + return st->pinners[c]; +} + inline Bitboard Position::check_squares(PieceType pt) const { return st->checkSquares[pt]; } diff --git a/src/search.cpp b/src/search.cpp index ba13680c..82d8bb9d 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -335,7 +335,7 @@ void Thread::search() { // for match (TC 60+0.6) results spanning a wide range of k values. PRNG rng(now()); double floatLevel = Options["UCI_LimitStrength"] ? - Utility::clamp(std::pow((Options["UCI_Elo"] - 1346.6) / 143.4, 1 / 0.806), 0.0, 20.0) : + std::clamp(std::pow((Options["UCI_Elo"] - 1346.6) / 143.4, 1 / 0.806), 0.0, 20.0) : double(Options["Skill Level"]); int intLevel = int(floatLevel) + ((floatLevel - int(floatLevel)) * 1024 > rng.rand() % 1024 ? 1 : 0); @@ -508,7 +508,7 @@ void Thread::search() { { double fallingEval = (318 + 6 * (mainThread->bestPreviousScore - bestValue) + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 825.0; - fallingEval = Utility::clamp(fallingEval, 0.5, 1.5); + fallingEval = std::clamp(fallingEval, 0.5, 1.5); // If the bestMove is stable over several iterations, reduce time accordingly timeReduction = lastBestMoveDepth + 9 < completedDepth ? 1.92 : 0.95; @@ -807,8 +807,9 @@ namespace { && eval <= alpha - RazorMargin) return qsearch(pos, ss, alpha, beta); - improving = (ss-2)->staticEval == VALUE_NONE ? (ss->staticEval > (ss-4)->staticEval - || (ss-4)->staticEval == VALUE_NONE) : ss->staticEval > (ss-2)->staticEval; + improving = (ss-2)->staticEval == VALUE_NONE + ? ss->staticEval > (ss-4)->staticEval || (ss-4)->staticEval == VALUE_NONE + : ss->staticEval > (ss-2)->staticEval; // Step 8. Futility pruning: child node (~50 Elo) if ( !PvNode @@ -879,8 +880,8 @@ namespace { // there and in further interactions with transposition table cutoff depth is set to depth - 3 // because probCut search has depth set to depth - 4 but we also do a move before it // so effective depth is equal to depth - 3 - && !( ttHit - && tte->depth() >= depth - 3 + && !( ttHit + && tte->depth() >= depth - 3 && ttValue != VALUE_NONE && ttValue < probCutBeta)) { @@ -1238,7 +1239,7 @@ moves_loop: // When in check, search starts from here r++; } - Depth d = Utility::clamp(newDepth - r, 1, newDepth); + Depth d = std::clamp(newDepth - r, 1, newDepth); value = -search(pos, ss+1, -(alpha+1), -alpha, d, true); diff --git a/src/timeman.cpp b/src/timeman.cpp index df4ba9b2..6d9c95ef 100644 --- a/src/timeman.cpp +++ b/src/timeman.cpp @@ -38,9 +38,9 @@ void TimeManagement::init(Search::LimitsType& limits, Color us, int ply) { TimePoint slowMover = TimePoint(Options["Slow Mover"]); TimePoint npmsec = TimePoint(Options["nodestime"]); - // opt_scale is a percentage of available time to use for the current move. - // max_scale is a multiplier applied to optimumTime. - double opt_scale, max_scale; + // optScale is a percentage of available time to use for the current move. + // maxScale is a multiplier applied to optimumTime. + double optScale, maxScale; // If we have to play in 'nodes as time' mode, then convert from time // to nodes, and use resulting values in time management formulas. @@ -75,22 +75,22 @@ void TimeManagement::init(Search::LimitsType& limits, Color us, int ply) { // game time for the current move, so also cap to 20% of available game time. if (limits.movestogo == 0) { - opt_scale = std::min(0.008 + std::pow(ply + 3.0, 0.5) / 250.0, + optScale = std::min(0.008 + std::pow(ply + 3.0, 0.5) / 250.0, 0.2 * limits.time[us] / double(timeLeft)); - max_scale = std::min(7.0, 4.0 + ply / 12.0); + maxScale = std::min(7.0, 4.0 + ply / 12.0); } // x moves in y seconds (+ z increment) else { - opt_scale = std::min((0.8 + ply / 128.0) / mtg, + optScale = std::min((0.8 + ply / 128.0) / mtg, 0.8 * limits.time[us] / double(timeLeft)); - max_scale = std::min(6.3, 1.5 + 0.11 * mtg); + maxScale = std::min(6.3, 1.5 + 0.11 * mtg); } // Never use more than 80% of the available time for this move - optimumTime = TimePoint(opt_scale * timeLeft); - maximumTime = TimePoint(std::min(0.8 * limits.time[us] - moveOverhead, max_scale * optimumTime)); + optimumTime = TimePoint(optScale * timeLeft); + maximumTime = TimePoint(std::min(0.8 * limits.time[us] - moveOverhead, maxScale * optimumTime)); if (Options["Ponder"]) optimumTime += optimumTime / 4; diff --git a/src/uci.cpp b/src/uci.cpp index d6486320..bc0ee0a0 100644 --- a/src/uci.cpp +++ b/src/uci.cpp @@ -211,7 +211,7 @@ namespace { double b = (((bs[0] * m + bs[1]) * m + bs[2]) * m) + bs[3]; // Transform eval to centipawns with limited range - double x = Utility::clamp(double(100 * v) / PawnValueEg, -1000.0, 1000.0); + double x = std::clamp(double(100 * v) / PawnValueEg, -1000.0, 1000.0); // Return win rate in per mille (rounded to nearest) return int(0.5 + 1000 / (1 + std::exp((a - x) / b))); -- 2.39.5