X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=9002c64c41b09b0944a7cc634721b28a805bacdc;hp=b3f413bf1ffa0bd20255ccd5f25893839dfd1e45;hb=8de29390f2d2bd31585b93ff46eae3051126f666;hpb=e53774bc49dd0aaa1c129ee98c09e1a56ef974fb diff --git a/src/movepick.cpp b/src/movepick.cpp index b3f413bf..9002c64c 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -2,13 +2,13 @@ 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) 2015-2016 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 the Free Software Foundation, either version 3 of the License, or (at your option) any later version. - Stockfish is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the @@ -26,12 +26,12 @@ namespace { enum Stages { - MAIN_SEARCH, CAPTURES_S1, KILLERS_S1, QUIETS_1_S1, QUIETS_2_S1, BAD_CAPTURES_S1, - EVASION, EVASIONS_S2, - QSEARCH_0, CAPTURES_S3, QUIET_CHECKS_S3, - QSEARCH_1, CAPTURES_S4, - PROBCUT, CAPTURES_S5, - RECAPTURE, CAPTURES_S6, + MAIN_SEARCH, GOOD_CAPTURES, KILLERS, GOOD_QUIETS, BAD_QUIETS, BAD_CAPTURES, + EVASION, ALL_EVASIONS, + QSEARCH_WITH_CHECKS, QCAPTURES_1, CHECKS, + QSEARCH_WITHOUT_CHECKS, QCAPTURES_2, + PROBCUT, PROBCUT_CAPTURES, + RECAPTURE, RECAPTURES, STOP }; @@ -51,8 +51,8 @@ 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. - inline Move pick_best(ExtMove* begin, ExtMove* end) + // 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; @@ -64,31 +64,23 @@ 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 +/// search captures, promotions, and some checks) and how important good move /// ordering is at the current node. MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h, - Move* cm, Move* fm, Search::Stack* s) : pos(p), history(h), depth(d) { + const CounterMoveStats& cmh, Move cm, Search::Stack* s) + : pos(p), history(h), counterMoveHistory(&cmh), ss(s), countermove(cm), depth(d) { assert(d > DEPTH_ZERO); - endBadCaptures = moves + MAX_MOVES - 1; - countermoves = cm; - followupmoves = fm; - ss = s; - - if (pos.checkers()) - stage = EVASION; - - else - stage = MAIN_SEARCH; - - ttMove = (ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE); + stage = pos.checkers() ? EVASION : MAIN_SEARCH; + ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE; endMoves += (ttMove != MOVE_NONE); } -MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h, - Square s) : pos(p), history(h) { +MovePicker::MovePicker(const Position& p, Move ttm, Depth d, + const HistoryStats& h, Square s) + : pos(p), history(h), counterMoveHistory(nullptr) { assert(d <= DEPTH_ZERO); @@ -96,10 +88,10 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& stage = EVASION; else if (d > DEPTH_QS_NO_CHECKS) - stage = QSEARCH_0; + stage = QSEARCH_WITH_CHECKS; else if (d > DEPTH_QS_RECAPTURES) - stage = QSEARCH_1; + stage = QSEARCH_WITHOUT_CHECKS; else { @@ -108,69 +100,56 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& ttm = MOVE_NONE; } - ttMove = (ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE); + ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE; endMoves += (ttMove != MOVE_NONE); } -MovePicker::MovePicker(const Position& p, Move ttm, const HistoryStats& h, PieceType pt) - : pos(p), history(h) { +MovePicker::MovePicker(const Position& p, Move ttm, const HistoryStats& h, Value th) + : pos(p), history(h), counterMoveHistory(nullptr), threshold(th) { assert(!pos.checkers()); stage = PROBCUT; - // In ProbCut we generate only captures that are better than the parent's - // captured piece. - captureThreshold = PieceValue[MG][pt]; - ttMove = (ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE); - - if (ttMove && (!pos.capture(ttMove) || pos.see(ttMove) <= captureThreshold)) - ttMove = MOVE_NONE; + // In ProbCut we generate captures with SEE higher than the given threshold + ttMove = ttm + && pos.pseudo_legal(ttm) + && pos.capture(ttm) + && pos.see(ttm) > threshold ? ttm : MOVE_NONE; endMoves += (ttMove != MOVE_NONE); } -/// score() assign a numerical value to each move in a move list. The moves with +/// score() assigns a numerical value to each move in a move list. The moves with /// highest values will be picked first. template<> void MovePicker::score() { - // Winning and equal captures in the main search are ordered by MVV/LVA. - // Suprisingly, this appears to perform slightly better than SEE based - // move ordering. The reason is probably that in a position with a winning - // capture, capturing a more valuable (but sufficiently defended) piece - // first usually doesn't hurt. The opponent will have to recapture, and - // the hanging piece will still be hanging (except in the unusual cases - // where it is possible to recapture with the hanging piece). Exchanging - // big pieces before capturing a hanging piece probably helps to reduce - // the subtree size. - // In main search we want to push captures with negative SEE values to the + // Winning and equal captures in the main search are ordered by MVV, preferring + // captures near our home rank. Surprisingly, this appears to perform slightly + // better than SEE-based move ordering: exchanging big pieces before capturing + // a hanging piece probably helps to reduce the subtree size. + // In the main search we want to push captures with negative SEE values to the // badCaptures[] array, but instead of doing it now we delay until the move - // has been picked up in pick_move_from_list(). This way we save some SEE - // calls in case we get a cutoff. + // has been picked up, saving some SEE calls in case we get a cutoff. for (auto& m : *this) - if (type_of(m) == ENPASSANT) - m.value = PieceValue[MG][PAWN] - Value(PAWN); - - else if (type_of(m) == PROMOTION) - m.value = PieceValue[MG][pos.piece_on(to_sq(m))] - Value(PAWN) - + PieceValue[MG][promotion_type(m)] - PieceValue[MG][PAWN]; - else - m.value = PieceValue[MG][pos.piece_on(to_sq(m))] - - Value(type_of(pos.moved_piece(m))); + m.value = PieceValue[MG][pos.piece_on(to_sq(m))] + - Value(200 * relative_rank(pos.side_to_move(), to_sq(m))); } template<> void MovePicker::score() { + for (auto& m : *this) - m.value = history[pos.moved_piece(m)][to_sq(m)]; + m.value = history[pos.moved_piece(m)][to_sq(m)] + + (*counterMoveHistory)[pos.moved_piece(m)][to_sq(m)]; } template<> void MovePicker::score() { - // Try good captures ordered by MVV/LVA, then non-captures if destination square - // is not under attack, ordered by history value, then bad-captures and quiet - // moves with a negative SEE. This last group is ordered by the SEE value. + // Try winning and equal captures ordered by MVV/LVA, then non-captures ordered + // by history value, then bad captures and quiet moves with a negative SEE ordered + // by SEE value. Value see; for (auto& m : *this) @@ -185,82 +164,64 @@ void MovePicker::score() { } -/// generate_next_stage() generates, scores and sorts the next bunch of moves, +/// generate_next_stage() generates, scores, and sorts the next bunch of moves /// when there are no more moves to try for the current stage. void MovePicker::generate_next_stage() { + assert(stage != STOP); + cur = moves; switch (++stage) { - case CAPTURES_S1: case CAPTURES_S3: case CAPTURES_S4: case CAPTURES_S5: case CAPTURES_S6: + case GOOD_CAPTURES: case QCAPTURES_1: case QCAPTURES_2: + case PROBCUT_CAPTURES: case RECAPTURES: endMoves = generate(pos, moves); score(); break; - case KILLERS_S1: - cur = killers; - endMoves = cur + 2; - + case KILLERS: killers[0] = ss->killers[0]; killers[1] = ss->killers[1]; - killers[2].move = killers[3].move = MOVE_NONE; - killers[4].move = killers[5].move = MOVE_NONE; - - // In SMP case countermoves[] and followupmoves[] could have duplicated entries - // in rare cases (less than 1 out of a million). This is harmless. - - // Be sure countermoves and followupmoves are different from killers - for (int i = 0; i < 2; ++i) - if ( countermoves[i] != killers[0] - && countermoves[i] != killers[1]) - *endMoves++ = countermoves[i]; - - for (int i = 0; i < 2; ++i) - if ( followupmoves[i] != killers[0] - && followupmoves[i] != killers[1] - && followupmoves[i] != killers[2] - && followupmoves[i] != killers[3]) - *endMoves++ = followupmoves[i]; + killers[2] = countermove; + cur = killers; + endMoves = cur + 2 + (countermove != killers[0] && countermove != killers[1]); break; - case QUIETS_1_S1: + case GOOD_QUIETS: endQuiets = endMoves = generate(pos, moves); score(); endMoves = std::partition(cur, endMoves, [](const ExtMove& m) { return m.value > VALUE_ZERO; }); insertion_sort(cur, endMoves); break; - case QUIETS_2_S1: + case BAD_QUIETS: cur = endMoves; endMoves = endQuiets; if (depth >= 3 * ONE_PLY) insertion_sort(cur, endMoves); break; - case BAD_CAPTURES_S1: - // Just pick them in reverse order to get MVV/LVA ordering + case BAD_CAPTURES: + // Just pick them in reverse order to get correct ordering cur = moves + MAX_MOVES - 1; endMoves = endBadCaptures; break; - case EVASIONS_S2: + case ALL_EVASIONS: endMoves = generate(pos, moves); if (endMoves - moves > 1) score(); break; - case QUIET_CHECKS_S3: + case CHECKS: endMoves = generate(pos, moves); break; - case EVASION: case QSEARCH_0: case QSEARCH_1: case PROBCUT: case RECAPTURE: + case EVASION: case QSEARCH_WITH_CHECKS: case QSEARCH_WITHOUT_CHECKS: + case PROBCUT: case RECAPTURE: case STOP: stage = STOP; - /* Fall through */ - - case STOP: - endMoves = cur + 1; // Avoid another generate_next_stage() call break; default: @@ -273,23 +234,24 @@ void MovePicker::generate_next_stage() { /// 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. -template<> -Move MovePicker::next_move() { + +Move MovePicker::next_move() { Move move; while (true) { - while (cur == endMoves) + while (cur == endMoves && stage != STOP) generate_next_stage(); switch (stage) { - case MAIN_SEARCH: case EVASION: case QSEARCH_0: case QSEARCH_1: case PROBCUT: + case MAIN_SEARCH: case EVASION: case QSEARCH_WITH_CHECKS: + case QSEARCH_WITHOUT_CHECKS: case PROBCUT: ++cur; return ttMove; - case CAPTURES_S1: + case GOOD_CAPTURES: move = pick_best(cur++, endMoves); if (move != ttMove) { @@ -301,7 +263,7 @@ Move MovePicker::next_move() { } break; - case KILLERS_S1: + case KILLERS: move = *cur++; if ( move != MOVE_NONE && move != ttMove @@ -310,40 +272,37 @@ Move MovePicker::next_move() { return move; break; - case QUIETS_1_S1: case QUIETS_2_S1: + case GOOD_QUIETS: case BAD_QUIETS: move = *cur++; if ( move != ttMove && move != killers[0] && move != killers[1] - && move != killers[2] - && move != killers[3] - && move != killers[4] - && move != killers[5]) + && move != killers[2]) return move; break; - case BAD_CAPTURES_S1: + case BAD_CAPTURES: return *cur--; - case EVASIONS_S2: case CAPTURES_S3: case CAPTURES_S4: + case ALL_EVASIONS: case QCAPTURES_1: case QCAPTURES_2: move = pick_best(cur++, endMoves); if (move != ttMove) return move; break; - case CAPTURES_S5: + case PROBCUT_CAPTURES: move = pick_best(cur++, endMoves); - if (move != ttMove && pos.see(move) > captureThreshold) + if (move != ttMove && pos.see(move) > threshold) return move; break; - case CAPTURES_S6: + case RECAPTURES: move = pick_best(cur++, endMoves); if (to_sq(move) == recaptureSquare) return move; break; - case QUIET_CHECKS_S3: + case CHECKS: move = *cur++; if (move != ttMove) return move; @@ -357,10 +316,3 @@ Move MovePicker::next_move() { } } } - - -/// Version of next_move() to use at split point nodes where the move is grabbed -/// from the split point's shared MovePicker object. This function is not thread -/// safe so must be lock protected by the caller. -template<> -Move MovePicker::next_move() { return ss->splitPoint->movePicker->next_move(); }