X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=a70785e769710bcd81ce704ca74bec8cadf03607;hp=51d85192a7c4df8b9c0cfdd0ea0c3adfb7b9ff13;hb=6ed81f09ffa513f0938c1a16fa4edd55e552c178;hpb=8dd6875240e05dbcc1fb6467ffb11ad360aa474c diff --git a/src/movepick.cpp b/src/movepick.cpp index 51d85192..a70785e7 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -2,7 +2,7 @@ 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) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2015-2019 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 @@ -25,10 +25,10 @@ namespace { enum Stages { - MAIN_SEARCH, CAPTURES_INIT, GOOD_CAPTURES, KILLERS, COUNTERMOVE, QUIET_INIT, QUIET, BAD_CAPTURES, - EVASION, EVASIONS_INIT, ALL_EVASIONS, - PROBCUT, PROBCUT_CAPTURES_INIT, PROBCUT_CAPTURES, - QSEARCH, QCAPTURES_INIT, QCAPTURES, QCHECKS, 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 @@ -46,15 +46,6 @@ 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 @@ -66,59 +57,49 @@ namespace { /// MovePicker constructor for the main search MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh, - const CapturePieceToHistory* cph, const PieceToHistory** ch, Move cm, Move* killers_p) - : pos(p), mainHistory(mh), captureHistory(cph), contHistory(ch), countermove(cm), - killers{killers_p[0], killers_p[1]}, depth(d){ + const CapturePieceToHistory* cph, const PieceToHistory** ch, Move cm, Move* killers) + : pos(p), mainHistory(mh), captureHistory(cph), continuationHistory(ch), + refutations{{killers[0], 0}, {killers[1], 0}, {cm, 0}}, depth(d) { assert(d > DEPTH_ZERO); - stage = pos.checkers() ? EVASION : MAIN_SEARCH; + stage = pos.checkers() ? EVASION_TT : MAIN_TT; ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE; stage += (ttMove == MOVE_NONE); } /// MovePicker constructor for quiescence search -MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh, const CapturePieceToHistory* cph, Square s) - : pos(p), mainHistory(mh), captureHistory(cph), depth(d) { +MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh, + const CapturePieceToHistory* cph, const PieceToHistory** ch, Square rs) + : pos(p), mainHistory(mh), captureHistory(cph), continuationHistory(ch), recaptureSquare(rs), depth(d) { assert(d <= DEPTH_ZERO); - if (pos.checkers()) - stage = EVASION; - - else if (d > DEPTH_QS_RECAPTURES) - stage = QSEARCH; - - else - { - stage = QSEARCH_RECAPTURES; - recaptureSquare = s; - return; - } - - ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE; + stage = pos.checkers() ? EVASION_TT : QSEARCH_TT; + ttMove = ttm + && (depth > DEPTH_QS_RECAPTURES || to_sq(ttm) == recaptureSquare) + && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE; stage += (ttMove == MOVE_NONE); } -/// MovePicker constructor for ProbCut: we generate captures with SEE higher +/// 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), threshold(th) { assert(!pos.checkers()); - stage = PROBCUT; + stage = PROBCUT_TT; ttMove = ttm - && pos.pseudo_legal(ttm) && pos.capture(ttm) + && pos.pseudo_legal(ttm) && pos.see_ge(ttm, threshold) ? ttm : MOVE_NONE; - stage += (ttMove == MOVE_NONE); } -/// 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 are ordered using the histories. +/// 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 histories. template void MovePicker::score() { @@ -127,13 +108,14 @@ void MovePicker::score() { for (auto& m : *this) if (Type == CAPTURES) m.value = PieceValue[MG][pos.piece_on(to_sq(m))] - + Value((*captureHistory)[pos.moved_piece(m)][to_sq(m)][type_of(pos.piece_on(to_sq(m)))]); + + (*captureHistory)[pos.moved_piece(m)][to_sq(m)][type_of(pos.piece_on(to_sq(m)))] / 8; else if (Type == 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)]; + + (*continuationHistory[0])[pos.moved_piece(m)][to_sq(m)] + + (*continuationHistory[1])[pos.moved_piece(m)][to_sq(m)] + + (*continuationHistory[3])[pos.moved_piece(m)][to_sq(m)] + + (*continuationHistory[5])[pos.moved_piece(m)][to_sq(m)] / 2; else // Type == EVASIONS { @@ -141,172 +123,145 @@ void MovePicker::score() { m.value = PieceValue[MG][pos.piece_on(to_sq(m))] - Value(type_of(pos.moved_piece(m))); else - m.value = (*mainHistory)[pos.side_to_move()][from_to(m)] - (1 << 28); + m.value = (*mainHistory)[pos.side_to_move()][from_to(m)] + + (*continuationHistory[0])[pos.moved_piece(m)][to_sq(m)] + - (1 << 28); } } -/// 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. +/// MovePicker::select() returns the next move satisfying a predicate function. +/// It never returns the TT move. +template +Move MovePicker::select(Pred filter) { -Move MovePicker::next_move(bool skipQuiets) { + while (cur < endMoves) + { + if (T == Best) + std::swap(*cur, *std::max_element(cur, endMoves)); + + if (*cur != ttMove && filter()) + return *cur++; - Move move; + cur++; + } + return MOVE_NONE; +} +/// 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: case PROBCUT: + case MAIN_TT: + case EVASION_TT: + case QSEARCH_TT: + case PROBCUT_TT: ++stage; return ttMove; - case CAPTURES_INIT: - case PROBCUT_CAPTURES_INIT: - case QCAPTURES_INIT: - case QSEARCH_RECAPTURES: - endBadCaptures = cur = moves; + case CAPTURE_INIT: + case PROBCUT_INIT: + case QCAPTURE_INIT: + cur = endBadCaptures = moves; endMoves = generate(pos, cur); + score(); ++stage; + goto top; - // Rebranch at the top of the switch via a recursive call - return next_move(skipQuiets); + case GOOD_CAPTURE: + if (select([&](){ + return pos.see_ge(*cur, Value(-55 * cur->value / 1024)) ? + // Move losing capture to endBadCaptures to be tried later + true : (*endBadCaptures++ = *cur, false); })) + return *(cur - 1); - case GOOD_CAPTURES: - while (cur < endMoves) - { - move = pick_best(cur++, endMoves); - if (move != ttMove) - { - if (pos.see_ge(move, Value(-55 * (cur-1)->value / 1024))) - return move; - - // Losing capture, move it to the beginning of the array - *endBadCaptures++ = move; - } - } + // Prepare the pointers to loop over the refutations array + cur = std::begin(refutations); + endMoves = std::end(refutations); - ++stage; - move = killers[0]; // First killer move - if ( move != MOVE_NONE - && move != ttMove - && pos.pseudo_legal(move) - && !pos.capture(move)) - return move; - /* fallthrough */ + // 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; - 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: + case REFUTATION: + if (select([&](){ return *cur != MOVE_NONE + && !pos.capture(*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 */ case QUIET_INIT: cur = endBadCaptures; endMoves = generate(pos, cur); + score(); partial_insertion_sort(cur, endMoves, -4000 * depth / ONE_PLY); ++stage; /* fallthrough */ case QUIET: - if (!skipQuiets) - while (cur < endMoves) - { - move = *cur++; - - if ( move != ttMove - && move != killers[0] - && move != killers[1] - && move != countermove) - return move; - } + 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; + ++stage; - cur = moves; // Point to beginning of bad captures /* 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 */ - 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_CAPTURES: - while (cur < endMoves) - { - move = pick_best(cur++, endMoves); - if ( move != ttMove - && pos.see_ge(move, threshold)) - return move; - } - break; + case PROBCUT: + return select([&](){ return pos.see_ge(*cur, threshold); }); + + 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: - while (cur < endMoves) - { - move = pick_best(cur++, endMoves); - if (move != ttMove) - return move; - } - if (depth <= DEPTH_QS_NO_CHECKS) - break; - cur = moves; - endMoves = generate(pos, cur); ++stage; /* fallthrough */ - case QCHECKS: - while (cur < endMoves) - { - move = cur++->move; - if (move != ttMove) - return move; - } - break; + case QCHECK_INIT: + cur = moves; + endMoves = generate(pos, cur); - case QRECAPTURES: - while (cur < endMoves) - { - move = *cur++; - if (to_sq(move) == recaptureSquare) - return move; - } - break; + ++stage; + /* fallthrough */ - default: - assert(false); + case QCHECK: + return select([](){ return true; }); } - return MOVE_NONE; + assert(false); + return MOVE_NONE; // Silence warning }