X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=c0809f2805f39c211bb9aba6f70cf7aa051dbf55;hp=2ea859a26fcf2b9ef4dadfe42d03c0806d082679;hb=cad300c;hpb=352bd6f5aa348e15909f50266fc5bdc003df35bf diff --git a/src/movepick.cpp b/src/movepick.cpp index 2ea859a2..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 @@ -21,40 +21,38 @@ #include #include "movepick.h" -#include "thread.h" 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 }; - // Our insertion sort, which is guaranteed to be stable, as it should be - void insertion_sort(ExtMove* begin, ExtMove* end) - { - ExtMove tmp, *p, *q; - - for (p = begin + 1; p < end; ++p) - { - tmp = *p; - for (q = p; q != begin && *(q-1) < tmp; --q) - *q = *(q-1); - *q = tmp; - } + // partial_insertion_sort() sorts moves in descending order up to and including + // a given limit. The order of moves smaller than the limit is left unspecified. + void partial_insertion_sort(ExtMove* begin, ExtMove* end, int limit) { + + for (ExtMove *sortedEnd = begin, *p = begin + 1; p < end; ++p) + if (p->value >= limit) + { + ExtMove tmp = *p, *q; + *p = *++sortedEnd; + for (q = sortedEnd; q != begin && *(q - 1) < tmp; --q) + *q = *(q - 1); + *q = tmp; + } } // 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; + Move pick_best(ExtMove* begin, ExtMove* end) { + + std::swap(*begin, *std::max_element(begin, end)); + return *begin; } } // namespace @@ -66,110 +64,76 @@ namespace { /// 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, Search::Stack* s) - : pos(p), ss(s), depth(d) { +/// 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){ assert(d > DEPTH_ZERO); - Square prevSq = to_sq((ss-1)->currentMove); - countermove = pos.this_thread()->counterMoves[pos.piece_on(prevSq)][prevSq]; - stage = pos.checkers() ? EVASION : MAIN_SEARCH; ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE; stage += (ttMove == MOVE_NONE); } -MovePicker::MovePicker(const Position& p, Move ttm, Depth d, Square s) - : pos(p) { +/// 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; - + && 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() { - - const HistoryStats& history = pos.this_thread()->history; - - const CounterMoveStats& cmh = *(ss-1)->counterMoves; - const CounterMoveStats& fmh = *(ss-2)->counterMoves; - const CounterMoveStats& fm2 = *(ss-4)->counterMoves; - - Color c = pos.side_to_move(); + static_assert(Type == CAPTURES || Type == QUIETS || Type == EVASIONS, "Wrong type"); for (auto& m : *this) - m.value = cmh[pos.moved_piece(m)][to_sq(m)] - + fmh[pos.moved_piece(m)][to_sq(m)] - + fm2[pos.moved_piece(m)][to_sq(m)] - + history.get(c, m); -} + if (Type == CAPTURES) + m.value = PieceValue[MG][pos.piece_on(to_sq(m))] + + (*captureHistory)[pos.moved_piece(m)][to_sq(m)][type_of(pos.piece_on(to_sq(m)))]; -template<> -void MovePicker::score() { - // Try captures ordered by MVV/LVA, then non-captures ordered by stats heuristics - const HistoryStats& history = pos.this_thread()->history; - Color c = pos.side_to_move(); + 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)]; - for (auto& m : *this) - if (pos.capture(m)) - m.value = PieceValue[MG][pos.piece_on(to_sq(m))] - - Value(type_of(pos.moved_piece(m))) + HistoryStats::Max; - else - m.value = history.get(c, 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 /// left. It picks the move with the biggest value from a list of generated moves @@ -181,86 +145,84 @@ 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; + // Rebranch at the top of the switch via a recursive call + return next_move(skipQuiets); + case GOOD_CAPTURES: while (cur < endMoves) { move = pick_best(cur++, endMoves); if (move != ttMove) { - if (pos.see_ge(move, VALUE_ZERO)) + 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 = ss->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 = ss->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: ++stage; move = countermove; if ( move != MOVE_NONE && move != ttMove - && move != ss->killers[0] - && move != ss->killers[1] + && 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(); - if (depth < 3 * ONE_PLY) - { - ExtMove* goodQuiet = std::partition(cur, endMoves, [](const ExtMove& m) - { return m.value > VALUE_ZERO; }); - insertion_sort(cur, goodQuiet); - } else - insertion_sort(cur, endMoves); + partial_insertion_sort(cur, endMoves, -4000 * depth / ONE_PLY); ++stage; + /* fallthrough */ case QUIET: - while ( cur < endMoves - && (!skipQuiets || cur->value >= VALUE_ZERO)) - { - move = *cur++; - - if ( move != ttMove - && move != ss->killers[0] - && move != ss->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 */ case BAD_CAPTURES: if (cur < endBadCaptures) @@ -272,6 +234,7 @@ Move MovePicker::next_move(bool skipQuiets) { endMoves = generate(pos, cur); score(); ++stage; + /* fallthrough */ case ALL_EVASIONS: while (cur < endMoves) @@ -282,12 +245,6 @@ Move MovePicker::next_move(bool skipQuiets) { } break; - case PROBCUT_INIT: - cur = moves; - endMoves = generate(pos, cur); - score(); - ++stage; - case PROBCUT_CAPTURES: while (cur < endMoves) { @@ -298,49 +255,30 @@ Move MovePicker::next_move(bool skipQuiets) { } break; - case QCAPTURES_1_INIT: case QCAPTURES_2_INIT: - cur = moves; - endMoves = generate(pos, cur); - score(); - ++stage; - - 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); ++stage; + /* fallthrough */ 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; - - case QRECAPTURES: - while (cur < endMoves) - { - move = pick_best(cur++, endMoves); - if (to_sq(move) == recaptureSquare) - return move; - } - break; - default: assert(false); }