X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fmovepick.cpp;h=5bb0fd6c27417d478b29d831613dd58a318c4b64;hb=edb4ab924f09abd7c6836c7017365dceccd76b80;hp=3b6ecbbfb05de5499d4972db052ade34536ac58b;hpb=f731bcadb7908f03c42e3d63fefe82552f09c926;p=stockfish diff --git a/src/movepick.cpp b/src/movepick.cpp index 3b6ecbbf..5bb0fd6c 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -1,8 +1,6 @@ /* 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) 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 @@ -18,19 +16,25 @@ along with this program. If not, see . */ +#include "movepick.h" + +#include #include +#include +#include -#include "movepick.h" +#include "bitboard.h" +#include "position.h" + +namespace Stockfish { namespace { enum Stages { - MAIN_SEARCH, CAPTURES_INIT, GOOD_CAPTURES, KILLERS, COUNTERMOVE, QUIET_INIT, QUIET, BAD_CAPTURES, - EVASION, EVASIONS_INIT, ALL_EVASIONS, - PROBCUT, PROBCUT_INIT, PROBCUT_CAPTURES, - QSEARCH_WITH_CHECKS, QCAPTURES_1_INIT, QCAPTURES_1, QCHECKS, - QSEARCH_NO_CHECKS, QCAPTURES_2_INIT, QCAPTURES_2, - QSEARCH_RECAPTURES, QRECAPTURES + MAIN_TT, CAPTURE_INIT, GOOD_CAPTURE, REFUTATION, QUIET_INIT, QUIET, BAD_CAPTURE, + EVASION_TT, EVASION_INIT, EVASION, + PROBCUT_TT, PROBCUT_INIT, PROBCUT, + QSEARCH_TT, QCAPTURE_INIT, QCAPTURE, QCHECK_INIT, QCHECK }; // partial_insertion_sort() sorts moves in descending order up to and including @@ -48,278 +52,274 @@ namespace { } } - // pick_best() finds the best move in the range (begin, end) and moves it to - // the front. It's faster than sorting all the moves in advance when there - // are few moves, e.g., the possible captures. - Move pick_best(ExtMove* begin, ExtMove* end) { - - std::swap(*begin, *std::max_element(begin, end)); - return *begin; - } - } // namespace -/// Constructors of the MovePicker class. As arguments we pass information -/// to help it to return the (presumably) good moves first, to decide which -/// moves to return (in the quiescence search, for instance, we only want to -/// search captures, promotions, and some checks) and how important good move -/// ordering is at the current node. +// Constructors of the MovePicker class. As arguments, we pass information +// to help it return the (presumably) good moves first, to decide which +// moves to return (in the quiescence search, for instance, we only want to +// search captures, promotions, and some checks) and how important a good +// move ordering is at the current node. +// MovePicker constructor for the main search MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh, - const PieceToHistory** ch, Move cm, Move* killers_p) - : pos(p), mainHistory(mh), contHistory(ch), countermove(cm), - killers{killers_p[0], killers_p[1]}, depth(d){ - - assert(d > DEPTH_ZERO); - - stage = pos.checkers() ? EVASION : MAIN_SEARCH; - ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE; - stage += (ttMove == MOVE_NONE); + const CapturePieceToHistory* cph, + const PieceToHistory** ch, + Move cm, + const Move* killers) + : pos(p), mainHistory(mh), captureHistory(cph), continuationHistory(ch), + ttMove(ttm), refutations{{killers[0], 0}, {killers[1], 0}, {cm, 0}}, depth(d) +{ + assert(d > 0); + + stage = (pos.checkers() ? EVASION_TT : MAIN_TT) + + !(ttm && pos.pseudo_legal(ttm)); } +// MovePicker constructor for quiescence search MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh, - const PieceToHistory** ch, Square s) - : pos(p), mainHistory(mh), contHistory(ch) { + const CapturePieceToHistory* cph, + const PieceToHistory** ch, + Square rs) + : pos(p), mainHistory(mh), captureHistory(cph), continuationHistory(ch), ttMove(ttm), recaptureSquare(rs), depth(d) +{ + assert(d <= 0); + + stage = (pos.checkers() ? EVASION_TT : QSEARCH_TT) + + !( ttm + && pos.pseudo_legal(ttm)); +} - assert(d <= DEPTH_ZERO); +// MovePicker constructor for ProbCut: we generate captures with SEE greater +// than or equal to the given threshold. +MovePicker::MovePicker(const Position& p, Move ttm, Value th, const CapturePieceToHistory* cph) + : pos(p), captureHistory(cph), ttMove(ttm), threshold(th) +{ + assert(!pos.checkers()); - if (pos.checkers()) - stage = EVASION; + stage = PROBCUT_TT + !(ttm && pos.capture_stage(ttm) + && pos.pseudo_legal(ttm) + && pos.see_ge(ttm, threshold)); +} - else if (d > DEPTH_QS_NO_CHECKS) - stage = QSEARCH_WITH_CHECKS; +// MovePicker::score() assigns a numerical value to each move in a list, used +// for sorting. Captures are ordered by Most Valuable Victim (MVV), preferring +// captures with a good history. Quiets moves are ordered using the history tables. +template +void MovePicker::score() { - else if (d > DEPTH_QS_RECAPTURES) - stage = QSEARCH_NO_CHECKS; + static_assert(Type == CAPTURES || Type == QUIETS || Type == EVASIONS, "Wrong type"); - else + [[maybe_unused]] Bitboard threatenedByPawn, threatenedByMinor, threatenedByRook, threatenedPieces; + if constexpr (Type == QUIETS) { - stage = QSEARCH_RECAPTURES; - recaptureSquare = s; - return; - } - - ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE; - stage += (ttMove == MOVE_NONE); -} + Color us = pos.side_to_move(); -MovePicker::MovePicker(const Position& p, Move ttm, Value th) - : pos(p), threshold(th) { + threatenedByPawn = pos.attacks_by(~us); + threatenedByMinor = pos.attacks_by(~us) | pos.attacks_by(~us) | threatenedByPawn; + threatenedByRook = pos.attacks_by(~us) | threatenedByMinor; - assert(!pos.checkers()); + // Pieces threatened by pieces of lesser material value + threatenedPieces = (pos.pieces(us, QUEEN) & threatenedByRook) + | (pos.pieces(us, ROOK) & threatenedByMinor) + | (pos.pieces(us, KNIGHT, BISHOP) & threatenedByPawn); + } - stage = PROBCUT; + for (auto& m : *this) + if constexpr (Type == CAPTURES) + m.value = (7 * int(PieceValue[pos.piece_on(to_sq(m))]) + + (*captureHistory)[pos.moved_piece(m)][to_sq(m)][type_of(pos.piece_on(to_sq(m)))]) / 16; - // In ProbCut we generate captures with SEE higher than or equal to the given threshold - ttMove = ttm - && pos.pseudo_legal(ttm) - && pos.capture(ttm) - && pos.see_ge(ttm, threshold) ? ttm : MOVE_NONE; + else if constexpr (Type == QUIETS) + { + Piece pc = pos.moved_piece(m); + PieceType pt = type_of(pos.moved_piece(m)); + Square from = from_sq(m); + Square to = to_sq(m); + + // histories + m.value = 2 * (*mainHistory)[pos.side_to_move()][from_to(m)]; + m.value += 2 * (*continuationHistory[0])[pc][to]; + m.value += (*continuationHistory[1])[pc][to]; + m.value += (*continuationHistory[2])[pc][to] / 4; + m.value += (*continuationHistory[3])[pc][to]; + m.value += (*continuationHistory[5])[pc][to]; + + // bonus for checks + m.value += bool(pos.check_squares(pt) & to) * 16384; + + // bonus for escaping from capture + m.value += threatenedPieces & from ? + (pt == QUEEN && !(to & threatenedByRook) ? 50000 + : pt == ROOK && !(to & threatenedByMinor) ? 25000 + : !(to & threatenedByPawn) ? 15000 + : 0 ) + : 0 ; + + // malus for putting piece en prise + m.value -= !(threatenedPieces & from) ? + (pt == QUEEN ? bool(to & threatenedByRook) * 50000 + + bool(to & threatenedByMinor) * 10000 + + bool(to & threatenedByPawn) * 20000 + : pt == ROOK ? bool(to & threatenedByMinor) * 25000 + + bool(to & threatenedByPawn) * 10000 + : pt != PAWN ? bool(to & threatenedByPawn) * 15000 + : 0 ) + : 0 ; + } - stage += (ttMove == MOVE_NONE); + else // Type == EVASIONS + { + if (pos.capture_stage(m)) + m.value = PieceValue[pos.piece_on(to_sq(m))] + - Value(type_of(pos.moved_piece(m))) + + (1 << 28); + else + m.value = (*mainHistory)[pos.side_to_move()][from_to(m)] + + (*continuationHistory[0])[pos.moved_piece(m)][to_sq(m)]; + } } -/// score() assigns a numerical value to each move in a list, used for sorting. -/// Captures are ordered by Most Valuable Victim (MVV), preferring captures -/// near our home rank. Quiets are ordered using the histories. -template -void MovePicker::score() { +// MovePicker::select() returns the next move satisfying a predicate function. +// It never returns the TT move. +template +Move MovePicker::select(Pred filter) { - for (auto& m : *this) - if (T == CAPTURES || (T == EVASIONS && pos.capture(m))) - m.value = PieceValue[MG][pos.piece_on(to_sq(m))] - - (T == EVASIONS ? Value(type_of(pos.moved_piece(m))) - : Value(200 * relative_rank(pos.side_to_move(), to_sq(m)))); - else if (T == QUIETS) - m.value = (*mainHistory)[pos.side_to_move()][from_to(m)] - + (*contHistory[0])[pos.moved_piece(m)][to_sq(m)] - + (*contHistory[1])[pos.moved_piece(m)][to_sq(m)] - + (*contHistory[3])[pos.moved_piece(m)][to_sq(m)]; - - else // Quiet evasions - m.value = (*mainHistory)[pos.side_to_move()][from_to(m)] - (1 << 28); -} + while (cur < endMoves) + { + if constexpr (T == Best) + std::swap(*cur, *std::max_element(cur, endMoves)); -/// next_move() is the most important method of the MovePicker class. It returns -/// a new pseudo legal move every time it is called, until there are no more moves -/// left. It picks the move with the biggest value from a list of generated moves -/// taking care not to return the ttMove if it has already been searched. + if (*cur != ttMove && filter()) + return *cur++; -Move MovePicker::next_move(bool skipQuiets) { + cur++; + } + return MOVE_NONE; +} - Move move; +// MovePicker::next_move() is the most important method of the MovePicker class. It +// returns a new pseudo-legal move every time it is called until there are no more +// moves left, picking the move with the highest score from a list of generated moves. +Move MovePicker::next_move(bool skipQuiets) { +top: switch (stage) { - case MAIN_SEARCH: case EVASION: case QSEARCH_WITH_CHECKS: - case QSEARCH_NO_CHECKS: case PROBCUT: + case MAIN_TT: + case EVASION_TT: + case QSEARCH_TT: + case PROBCUT_TT: ++stage; return ttMove; - case CAPTURES_INIT: - endBadCaptures = cur = moves; + case CAPTURE_INIT: + case PROBCUT_INIT: + case QCAPTURE_INIT: + cur = endBadCaptures = moves; endMoves = generate(pos, cur); + score(); + partial_insertion_sort(cur, endMoves, std::numeric_limits::min()); ++stage; - /* fallthrough */ + goto top; - case GOOD_CAPTURES: - while (cur < endMoves) - { - move = pick_best(cur++, endMoves); - if (move != ttMove) - { - if (pos.see_ge(move)) - return move; - - // Losing capture, move it to the beginning of the array - *endBadCaptures++ = move; - } - } + case GOOD_CAPTURE: + if (select([&](){ + return pos.see_ge(*cur, Value(-cur->value)) ? + // Move losing capture to endBadCaptures to be tried later + true : (*endBadCaptures++ = *cur, false); })) + return *(cur - 1); + + // Prepare the pointers to loop over the refutations array + cur = std::begin(refutations); + endMoves = std::end(refutations); + + // If the countermove is the same as a killer, skip it + if ( refutations[0].move == refutations[2].move + || refutations[1].move == refutations[2].move) + --endMoves; ++stage; - move = killers[0]; // First killer move - if ( move != MOVE_NONE - && move != ttMove - && pos.pseudo_legal(move) - && !pos.capture(move)) - return move; - /* fallthrough */ - - case KILLERS: - ++stage; - move = killers[1]; // Second killer move - if ( move != MOVE_NONE - && move != ttMove - && pos.pseudo_legal(move) - && !pos.capture(move)) - return move; - /* fallthrough */ - - case COUNTERMOVE: + [[fallthrough]]; + + case REFUTATION: + if (select([&](){ return *cur != MOVE_NONE + && !pos.capture_stage(*cur) + && pos.pseudo_legal(*cur); })) + return *(cur - 1); ++stage; - move = countermove; - if ( move != MOVE_NONE - && move != ttMove - && move != killers[0] - && move != killers[1] - && pos.pseudo_legal(move) - && !pos.capture(move)) - return move; - /* fallthrough */ + [[fallthrough]]; case QUIET_INIT: - cur = endBadCaptures; - endMoves = generate(pos, cur); - score(); - partial_insertion_sort(cur, endMoves, -4000 * depth / ONE_PLY); + if (!skipQuiets) + { + cur = endBadCaptures; + endMoves = generate(pos, cur); + + score(); + partial_insertion_sort(cur, endMoves, -3000 * depth); + } + ++stage; - /* fallthrough */ + [[fallthrough]]; case QUIET: - while ( cur < endMoves - && (!skipQuiets || cur->value >= VALUE_ZERO)) - { - move = *cur++; + if ( !skipQuiets + && select([&](){return *cur != refutations[0].move + && *cur != refutations[1].move + && *cur != refutations[2].move;})) + return *(cur - 1); + + // Prepare the pointers to loop over the bad captures + cur = moves; + endMoves = endBadCaptures; - if ( move != ttMove - && move != killers[0] - && move != killers[1] - && move != countermove) - return move; - } ++stage; - cur = moves; // Point to beginning of bad captures - /* fallthrough */ + [[fallthrough]]; - case BAD_CAPTURES: - if (cur < endBadCaptures) - return *cur++; - break; + case BAD_CAPTURE: + return select([](){ return true; }); - case EVASIONS_INIT: + case EVASION_INIT: cur = moves; endMoves = generate(pos, cur); + score(); ++stage; - /* fallthrough */ + [[fallthrough]]; - case ALL_EVASIONS: - while (cur < endMoves) - { - move = pick_best(cur++, endMoves); - if (move != ttMove) - return move; - } - break; + case EVASION: + return select([](){ return true; }); - case PROBCUT_INIT: - cur = moves; - endMoves = generate(pos, cur); - score(); - ++stage; - /* fallthrough */ + case PROBCUT: + return select([&](){ return pos.see_ge(*cur, threshold); }); - case PROBCUT_CAPTURES: - while (cur < endMoves) - { - move = pick_best(cur++, endMoves); - if ( move != ttMove - && pos.see_ge(move, threshold)) - return move; - } - break; + case QCAPTURE: + if (select([&](){ return depth > DEPTH_QS_RECAPTURES + || to_sq(*cur) == recaptureSquare; })) + return *(cur - 1); + + // If we did not find any move and we do not try checks, we have finished + if (depth != DEPTH_QS_CHECKS) + return MOVE_NONE; - case QCAPTURES_1_INIT: case QCAPTURES_2_INIT: - cur = moves; - endMoves = generate(pos, cur); - score(); ++stage; - /* fallthrough */ + [[fallthrough]]; - case QCAPTURES_1: case QCAPTURES_2: - while (cur < endMoves) - { - move = pick_best(cur++, endMoves); - if (move != ttMove) - return move; - } - if (stage == QCAPTURES_2) - break; + case QCHECK_INIT: cur = moves; endMoves = generate(pos, cur); - ++stage; - /* fallthrough */ - case QCHECKS: - while (cur < endMoves) - { - move = cur++->move; - if (move != ttMove) - return move; - } - break; - - case QSEARCH_RECAPTURES: - cur = moves; - endMoves = generate(pos, cur); - score(); ++stage; - /* fallthrough */ + [[fallthrough]]; - case QRECAPTURES: - while (cur < endMoves) - { - move = pick_best(cur++, endMoves); - if (to_sq(move) == recaptureSquare) - return move; - } - break; - - default: - assert(false); + case QCHECK: + return select([](){ return true; }); } - return MOVE_NONE; + assert(false); + return MOVE_NONE; // Silence warning } + +} // namespace Stockfish