X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=c0809f2805f39c211bb9aba6f70cf7aa051dbf55;hp=1f946eadca40d65ed2ccfea3abf1fdf524129809;hb=cad300c;hpb=b40e45c1cc51bd228898314264d6d241478b23d8 diff --git a/src/movepick.cpp b/src/movepick.cpp index 1f946ead..c0809f28 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) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2015-2018 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 @@ -25,12 +25,10 @@ namespace { enum Stages { - MAIN_SEARCH, CAPTURES_INIT, GOOD_CAPTURES, KILLERS, COUNTERMOVE, QUIET_INIT, QUIET, BAD_CAPTURES, + MAIN_SEARCH, CAPTURES_INIT, GOOD_CAPTURES, KILLER0, KILLER1, 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 + PROBCUT, PROBCUT_CAPTURES_INIT, PROBCUT_CAPTURES, + QSEARCH, QCAPTURES_INIT, QCAPTURES, QCHECKS }; // partial_insertion_sort() sorts moves in descending order up to and including @@ -66,9 +64,10 @@ namespace { /// search captures, promotions, and some checks) and how important 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), + 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){ assert(d > DEPTH_ZERO); @@ -78,86 +77,62 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHist stage += (ttMove == MOVE_NONE); } -MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh, - const PieceToHistory** ch, Square s) - : pos(p), mainHistory(mh), contHistory(ch) { +/// 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), recaptureSquare(s), depth(d) { assert(d <= DEPTH_ZERO); - if (pos.checkers()) - stage = EVASION; - - else if (d > DEPTH_QS_NO_CHECKS) - stage = QSEARCH_WITH_CHECKS; - - else if (d > DEPTH_QS_RECAPTURES) - stage = QSEARCH_NO_CHECKS; - - else - { - stage = QSEARCH_RECAPTURES; - recaptureSquare = s; - return; - } - - ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE; + stage = pos.checkers() ? EVASION : QSEARCH; + ttMove = ttm + && pos.pseudo_legal(ttm) + && (depth > DEPTH_QS_RECAPTURES || to_sq(ttm) == recaptureSquare) ? ttm : MOVE_NONE; stage += (ttMove == MOVE_NONE); } -MovePicker::MovePicker(const Position& p, Move ttm, Value th) - : pos(p), threshold(th) { +/// MovePicker constructor for ProbCut: we generate captures with SEE higher +/// 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; - - // 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; - 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. +template +void MovePicker::score() { -/// 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, 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, saving some SEE calls in case we get a cutoff. - for (auto& m : *this) - 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 = (*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)]; -} + static_assert(Type == CAPTURES || Type == QUIETS || Type == EVASIONS, "Wrong type"); -template<> -void MovePicker::score() { - // Try captures ordered by MVV/LVA, then non-captures ordered by stats heuristics for (auto& m : *this) - if (pos.capture(m)) + if (Type == CAPTURES) m.value = PieceValue[MG][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)]; -} + + (*captureHistory)[pos.moved_piece(m)][to_sq(m)][type_of(pos.piece_on(to_sq(m)))]; + 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)]; + + else // Type == EVASIONS + { + if (pos.capture(m)) + 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); + } +} /// 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 @@ -170,17 +145,20 @@ Move MovePicker::next_move(bool skipQuiets) { switch (stage) { - case MAIN_SEARCH: case EVASION: case QSEARCH_WITH_CHECKS: - case QSEARCH_NO_CHECKS: case PROBCUT: + case MAIN_SEARCH: case EVASION: case QSEARCH: case PROBCUT: ++stage; return ttMove; case CAPTURES_INIT: + case PROBCUT_CAPTURES_INIT: + case QCAPTURES_INIT: endBadCaptures = cur = moves; endMoves = generate(pos, cur); score(); ++stage; - /* fallthrough */ + + // Rebranch at the top of the switch via a recursive call + return next_move(skipQuiets); case GOOD_CAPTURES: while (cur < endMoves) @@ -188,31 +166,27 @@ Move MovePicker::next_move(bool skipQuiets) { move = pick_best(cur++, endMoves); if (move != ttMove) { - if (pos.see_ge(move)) + 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; } } - ++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; + case KILLER0: + case KILLER1: + do + { + move = killers[++stage - KILLER1]; + if ( move != MOVE_NONE + && move != ttMove + && pos.pseudo_legal(move) + && !pos.capture(move)) + return move; + } while (stage <= KILLER1); /* fallthrough */ case COUNTERMOVE: @@ -236,17 +210,16 @@ Move MovePicker::next_move(bool skipQuiets) { /* fallthrough */ case QUIET: - while ( cur < endMoves - && (!skipQuiets || cur->value >= VALUE_ZERO)) - { - move = *cur++; - - if ( move != ttMove - && move != killers[0] - && move != killers[1] - && move != countermove) - return move; - } + if (!skipQuiets) + while (cur < endMoves) + { + move = *cur++; + if ( move != ttMove + && move != killers[0] + && move != killers[1] + && move != countermove) + return move; + } ++stage; cur = moves; // Point to beginning of bad captures /* fallthrough */ @@ -272,13 +245,6 @@ Move MovePicker::next_move(bool skipQuiets) { } break; - case PROBCUT_INIT: - cur = moves; - endMoves = generate(pos, cur); - score(); - ++stage; - /* fallthrough */ - case PROBCUT_CAPTURES: while (cur < endMoves) { @@ -289,21 +255,15 @@ Move MovePicker::next_move(bool skipQuiets) { } break; - case QCAPTURES_1_INIT: case QCAPTURES_2_INIT: - cur = moves; - endMoves = generate(pos, cur); - score(); - ++stage; - /* fallthrough */ - - case QCAPTURES_1: case QCAPTURES_2: + case QCAPTURES: while (cur < endMoves) { move = pick_best(cur++, endMoves); - if (move != ttMove) + if ( move != ttMove + && (depth > DEPTH_QS_RECAPTURES || to_sq(move) == recaptureSquare)) return move; } - if (stage == QCAPTURES_2) + if (depth <= DEPTH_QS_NO_CHECKS) break; cur = moves; endMoves = generate(pos, cur); @@ -313,28 +273,12 @@ Move MovePicker::next_move(bool skipQuiets) { case QCHECKS: while (cur < endMoves) { - move = cur++->move; + move = *cur++; if (move != ttMove) return move; } break; - case QSEARCH_RECAPTURES: - cur = moves; - endMoves = generate(pos, cur); - score(); - ++stage; - /* fallthrough */ - - case QRECAPTURES: - while (cur < endMoves) - { - move = pick_best(cur++, endMoves); - if (to_sq(move) == recaptureSquare) - return move; - } - break; - default: assert(false); }