X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fsyzygy%2Ftbprobe.cpp;h=b7ba32407456f810b0354c4bc920d8c5c839fdfb;hb=b60f9cc4515cdfb657a0166abb29a60257cc59e1;hp=831c8259c538c103b6d4eb4a15fe1577ca8fbd79;hpb=83eac08e7562d93787f75eccd4b7781c4bd45dd3;p=stockfish diff --git a/src/syzygy/tbprobe.cpp b/src/syzygy/tbprobe.cpp index 831c8259..b7ba3240 100644 --- a/src/syzygy/tbprobe.cpp +++ b/src/syzygy/tbprobe.cpp @@ -1,6 +1,6 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 - Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file) + 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 @@ -59,6 +59,7 @@ namespace Stockfish { namespace { constexpr int TBPIECES = 7; // Max number of supported pieces +constexpr int MAX_DTZ = 1 << 18; // Max DTZ supported, large enough to deal with the syzygy TB limit. enum { BigEndian, LittleEndian }; enum TBType { WDL, DTZ }; // Used as template parameter @@ -105,9 +106,6 @@ template<> inline void swap_endian(uint8_t&) {} template T number(void* addr) { - static const union { uint32_t i; char c[4]; } Le = { 0x01020304 }; - static const bool IsLittleEndian = (Le.c[0] == 4); - T v; if ((uintptr_t)addr & (alignof(T) - 1)) // Unaligned pointer (very rare) @@ -772,7 +770,7 @@ Ret do_probe_table(const Position& pos, T* entry, WDLScore wdl, ProbeState* resu goto encode_remaining; // With pawns we have finished special treatments } - // In positions withouth pawns, we further flip the squares to ensure leading + // In positions without pawns, we further flip the squares to ensure leading // piece is below RANK_5. if (rank_of(squares[0]) > RANK_4) for (int i = 0; i < size; ++i) @@ -815,7 +813,7 @@ Ret do_probe_table(const Position& pos, T* entry, WDLScore wdl, ProbeState* resu // Rs "together" in 62 * 61 / 2 ways (we divide by 2 because rooks can be // swapped and still get the same position.) // - // In case we have at least 3 unique pieces (inlcuded kings) we encode them + // In case we have at least 3 unique pieces (included kings) we encode them // together. if (entry->hasUniquePieces) { @@ -830,7 +828,7 @@ Ret do_probe_table(const Position& pos, T* entry, WDLScore wdl, ProbeState* resu + (squares[1] - adjust1)) * 62 + squares[2] - adjust2; - // First piece is on a1-h8 diagonal, second below: map this occurence to + // First piece is on a1-h8 diagonal, second below: map this occurrence to // 6 to differentiate from the above case, rank_of() maps a1-d4 diagonal // to 0...3 and finally MapB1H1H7[] maps the b1-h1-h7 triangle to 0..27. else if (off_A1H8(squares[1])) @@ -860,7 +858,7 @@ encode_remaining: idx *= d->groupIdx[0]; Square* groupSq = squares + d->groupLen[0]; - // Encode remainig pawns then pieces according to square, in ascending order + // Encode remaining pawns then pieces according to square, in ascending order bool remainingPawns = entry->hasPawns && entry->pawnCount[1]; while (d->groupLen[++next]) @@ -888,7 +886,7 @@ encode_remaining: // Group together pieces that will be encoded together. The general rule is that // a group contains pieces of same type and color. The exception is the leading -// group that, in case of positions withouth pawns, can be formed by 3 different +// group that, in case of positions without pawns, can be formed by 3 different // pieces (default) or by the king pair when there is not a unique piece apart // from the kings. When there are pawns, pawns are always first in pieces[]. // @@ -920,7 +918,7 @@ void set_groups(T& e, PairsData* d, int order[], File f) { // // This ensures unique encoding for the whole position. The order of the // groups is a per-table parameter and could not follow the canonical leading - // pawns/pieces -> remainig pawns -> remaining pieces. In particular the + // pawns/pieces -> remaining pawns -> remaining pieces. In particular the // first group is at order[0] position and the remaining pawns, when present, // are at order[1] position. bool pp = e.hasPawns && e.pawnCount[1]; // Pawns on both sides @@ -940,7 +938,7 @@ void set_groups(T& e, PairsData* d, int order[], File f) { d->groupIdx[1] = idx; idx *= Binomial[d->groupLen[1]][48 - d->groupLen[0]]; } - else // Remainig pieces + else // Remaining pieces { d->groupIdx[next] = idx; idx *= Binomial[d->groupLen[next]][freeSquares]; @@ -950,7 +948,7 @@ void set_groups(T& e, PairsData* d, int order[], File f) { d->groupIdx[n] = idx; } -// In Recursive Pairing each symbol represents a pair of childern symbols. So +// In Recursive Pairing each symbol represents a pair of children symbols. So // read d->btree[] symbols data and expand each one in his left and right child // symbol until reaching the leafs that represent the symbol value. uint8_t set_symlen(PairsData* d, Sym s, std::vector& visited) { @@ -1293,7 +1291,7 @@ void Tablebases::init(const std::string& paths) { for (auto s : diagonal) MapA1D1D4[s] = code++; - // MapKK[] encodes all the 461 possible legal positions of two kings where + // MapKK[] encodes all the 462 possible legal positions of two kings where // the first is in the a1-d1-d4 triangle. If the first king is on the a1-d4 // diagonal, the other one shall not to be above the a1-h8 diagonal. std::vector> bothOnDiagonal; @@ -1320,7 +1318,7 @@ void Tablebases::init(const std::string& paths) { for (auto p : bothOnDiagonal) MapKK[p.first][p.second] = code++; - // Binomial[] stores the Binomial Coefficents using Pascal rule. There + // Binomial[] stores the Binomial Coefficients using Pascal rule. There // are Binomial[k][n] ways to choose k elements from a set of n elements. Binomial[0][0] = 1; @@ -1340,7 +1338,7 @@ void Tablebases::init(const std::string& paths) { for (int leadPawnsCnt = 1; leadPawnsCnt <= 5; ++leadPawnsCnt) for (File f = FILE_A; f <= FILE_D; ++f) { - // Restart the index at every file because TB table is splitted + // Restart the index at every file because TB table is split // by file, so we can reuse the same index for different files. int idx = 0; @@ -1516,7 +1514,7 @@ int Tablebases::probe_dtz(Position& pos, ProbeState* result) { // A return value false indicates that not all probes were successful. bool Tablebases::root_probe(Position& pos, Search::RootMoves& rootMoves) { - ProbeState result; + ProbeState result = OK; StateInfo st; // Obtain 50-move counter for the root position @@ -1525,7 +1523,7 @@ bool Tablebases::root_probe(Position& pos, Search::RootMoves& rootMoves) { // Check whether a position was repeated since the last zeroing move. bool rep = pos.has_repeated(); - int dtz, bound = Options["Syzygy50MoveRule"] ? 900 : 1; + int dtz, bound = Options["Syzygy50MoveRule"] ? (MAX_DTZ - 100) : 1; // Probe and rank each move for (auto& m : rootMoves) @@ -1539,6 +1537,14 @@ bool Tablebases::root_probe(Position& pos, Search::RootMoves& rootMoves) { WDLScore wdl = -probe_wdl(pos, &result); dtz = dtz_before_zeroing(wdl); } + else if (pos.is_draw(1)) + { + // In case a root move leads to a draw by repetition or + // 50-move rule, we set dtz to zero. Note: since we are + // only 1 ply from the root, this must be a true 3-fold + // repetition inside the game history. + dtz = 0; + } else { // Otherwise, take dtz for the new position and correct by 1 ply @@ -1560,8 +1566,8 @@ bool Tablebases::root_probe(Position& pos, Search::RootMoves& rootMoves) { // Better moves are ranked higher. Certain wins are ranked equally. // Losing moves are ranked equally unless a 50-move draw is in sight. - int r = dtz > 0 ? (dtz + cnt50 <= 99 && !rep ? 1000 : 1000 - (dtz + cnt50)) - : dtz < 0 ? (-dtz * 2 + cnt50 < 100 ? -1000 : -1000 + (-dtz + cnt50)) + int r = dtz > 0 ? (dtz + cnt50 <= 99 && !rep ? MAX_DTZ : MAX_DTZ - (dtz + cnt50)) + : dtz < 0 ? (-dtz * 2 + cnt50 < 100 ? -MAX_DTZ : -MAX_DTZ + (-dtz + cnt50)) : 0; m.tbRank = r; @@ -1569,9 +1575,9 @@ bool Tablebases::root_probe(Position& pos, Search::RootMoves& rootMoves) { // 1 cp to cursed wins and let it grow to 49 cp as the positions gets // closer to a real win. m.tbScore = r >= bound ? VALUE_MATE - MAX_PLY - 1 - : r > 0 ? Value((std::max( 3, r - 800) * int(PawnValueEg)) / 200) + : r > 0 ? Value((std::max( 3, r - (MAX_DTZ - 200)) * int(PawnValueEg)) / 200) : r == 0 ? VALUE_DRAW - : r > -bound ? Value((std::min(-3, r + 800) * int(PawnValueEg)) / 200) + : r > -bound ? Value((std::min(-3, r + (MAX_DTZ - 200)) * int(PawnValueEg)) / 200) : -VALUE_MATE + MAX_PLY + 1; } @@ -1585,10 +1591,11 @@ bool Tablebases::root_probe(Position& pos, Search::RootMoves& rootMoves) { // A return value false indicates that not all probes were successful. bool Tablebases::root_probe_wdl(Position& pos, Search::RootMoves& rootMoves) { - static const int WDL_to_rank[] = { -1000, -899, 0, 899, 1000 }; + static const int WDL_to_rank[] = { -MAX_DTZ, -MAX_DTZ + 101, 0, MAX_DTZ - 101, MAX_DTZ }; - ProbeState result; + ProbeState result = OK; StateInfo st; + WDLScore wdl; bool rule50 = Options["Syzygy50MoveRule"]; @@ -1597,7 +1604,10 @@ bool Tablebases::root_probe_wdl(Position& pos, Search::RootMoves& rootMoves) { { pos.do_move(m.pv[0], st); - WDLScore wdl = -probe_wdl(pos, &result); + if (pos.is_draw(1)) + wdl = WDLDraw; + else + wdl = -probe_wdl(pos, &result); pos.undo_move(m.pv[0]);