X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=3b6ecbbfb05de5499d4972db052ade34536ac58b;hp=622ef8a9a9dd896ea9dbcab8257dc7a1ee4cac3a;hb=f731bcadb7908f03c42e3d63fefe82552f09c926;hpb=01ee509a5c33e11d7d62d2f325f55720d8be9cfb diff --git a/src/movepick.cpp b/src/movepick.cpp index 622ef8a9..3b6ecbbf 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) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2015-2017 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 @@ -21,41 +21,40 @@ #include #include "movepick.h" -#include "thread.h" namespace { enum Stages { - MAIN_SEARCH, GOOD_CAPTURES_INIT, GOOD_CAPTURES, KILLERS, KILLERS_2, - QUIET_INIT, QUIET, BAD_CAPTURES, - EVASION, ALL_EVASIONS, - QSEARCH_WITH_CHECKS, QCAPTURES_CHECKS_INIT, QCAPTURES_CHECKS, CHECKS, - QSEARCH_WITHOUT_CHECKS, QCAPTURES_NO_CHECKS, REMAINING, - RECAPTURE, RECAPTURES, - PROBCUT, PROBCUT_INIT, PROBCUT_CAPTURES + 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 }; - // 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 @@ -67,21 +66,21 @@ 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::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); - 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::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh, + const PieceToHistory** ch, Square s) + : pos(p), mainHistory(mh), contHistory(ch) { assert(d <= DEPTH_ZERO); @@ -92,11 +91,11 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, Square s) stage = QSEARCH_WITH_CHECKS; else if (d > DEPTH_QS_RECAPTURES) - stage = QSEARCH_WITHOUT_CHECKS; + stage = QSEARCH_NO_CHECKS; else { - stage = RECAPTURE; + stage = QSEARCH_RECAPTURES; recaptureSquare = s; return; } @@ -112,95 +111,58 @@ MovePicker::MovePicker(const Position& p, Move ttm, Value th) stage = PROBCUT; - // In ProbCut we generate captures with SEE higher than the given threshold + // 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(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 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 FromToStats& fromTo = pos.this_thread()->fromTo; - - const CounterMoveStats* cm = (ss-1)->counterMoves; - const CounterMoveStats* fm = (ss-2)->counterMoves; - const CounterMoveStats* f2 = (ss-4)->counterMoves; - - Color c = pos.side_to_move(); - - for (auto& m : *this) - m.value = history[pos.moved_piece(m)][to_sq(m)] - + (cm ? (*cm)[pos.moved_piece(m)][to_sq(m)] : VALUE_ZERO) - + (fm ? (*fm)[pos.moved_piece(m)][to_sq(m)] : VALUE_ZERO) - + (f2 ? (*f2)[pos.moved_piece(m)][to_sq(m)] : VALUE_ZERO) - + fromTo.get(c, m); -} - -template<> -void MovePicker::score() { - // 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. - const HistoryStats& history = pos.this_thread()->history; - const FromToStats& fromTo = pos.this_thread()->fromTo; - Color c = pos.side_to_move(); - Value see; +/// 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() { for (auto& m : *this) - if ((see = pos.see_sign(m)) < VALUE_ZERO) - m.value = see - HistoryStats::Max; // At the bottom - - else 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[pos.moved_piece(m)][to_sq(m)] + fromTo.get(c, m); + 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); } - /// 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. -Move MovePicker::next_move() { +Move MovePicker::next_move(bool skipQuiets) { Move move; switch (stage) { case MAIN_SEARCH: case EVASION: case QSEARCH_WITH_CHECKS: - case QSEARCH_WITHOUT_CHECKS: case PROBCUT: + case QSEARCH_NO_CHECKS: case PROBCUT: ++stage; return ttMove; - case GOOD_CAPTURES_INIT: + case CAPTURES_INIT: endBadCaptures = cur = moves; endMoves = generate(pos, cur); score(); ++stage; + /* fallthrough */ case GOOD_CAPTURES: while (cur < endMoves) @@ -208,140 +170,149 @@ Move MovePicker::next_move() { move = pick_best(cur++, endMoves); if (move != ttMove) { - if (pos.see_sign(move) >= VALUE_ZERO) + if (pos.see_ge(move)) return move; // Losing capture, move it to the beginning of the array *endBadCaptures++ = move; } } - ++stage; - // First killer move - move = ss->killers[0]; + ++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 = ss->killers[1]; // Second killer move + move = killers[1]; // Second killer move if ( move != MOVE_NONE && move != ttMove && pos.pseudo_legal(move) && !pos.capture(move)) return move; + /* fallthrough */ - case KILLERS_2: + 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) + while ( cur < endMoves + && (!skipQuiets || cur->value >= VALUE_ZERO)) { move = *cur++; + if ( move != ttMove - && move != ss->killers[0] - && move != ss->killers[1] + && 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) return *cur++; break; - case ALL_EVASIONS: + case EVASIONS_INIT: cur = moves; endMoves = generate(pos, cur); - if (endMoves - cur > 1) - score(); - stage = REMAINING; - goto remaining; - - case QCAPTURES_CHECKS_INIT: - case QCAPTURES_NO_CHECKS: - cur = moves; - endMoves = generate(pos, cur); - score(); + score(); ++stage; + /* fallthrough */ -remaining: - case QCAPTURES_CHECKS: - case REMAINING: + case ALL_EVASIONS: while (cur < endMoves) { move = pick_best(cur++, endMoves); if (move != ttMove) return move; } - if (stage == REMAINING) - break; + break; + + case PROBCUT_INIT: cur = moves; - endMoves = generate(pos, cur); + endMoves = generate(pos, cur); + score(); ++stage; + /* fallthrough */ - case CHECKS: + case PROBCUT_CAPTURES: while (cur < endMoves) { - move = cur++->move; - if (move != ttMove) + move = pick_best(cur++, endMoves); + if ( move != ttMove + && pos.see_ge(move, threshold)) return move; } break; - case RECAPTURE: + case QCAPTURES_1_INIT: case QCAPTURES_2_INIT: cur = moves; endMoves = generate(pos, cur); score(); ++stage; + /* fallthrough */ - case RECAPTURES: + case QCAPTURES_1: case QCAPTURES_2: while (cur < endMoves) { move = pick_best(cur++, endMoves); - if (to_sq(move) == recaptureSquare) + if (move != ttMove) + return move; + } + if (stage == QCAPTURES_2) + break; + cur = moves; + endMoves = generate(pos, cur); + ++stage; + /* fallthrough */ + + case QCHECKS: + while (cur < endMoves) + { + move = cur++->move; + if (move != ttMove) return move; } break; - case PROBCUT_INIT: + case QSEARCH_RECAPTURES: cur = moves; endMoves = generate(pos, cur); score(); ++stage; + /* fallthrough */ - case PROBCUT_CAPTURES: + case QRECAPTURES: while (cur < endMoves) { move = pick_best(cur++, endMoves); - if ( move != ttMove - && pos.see(move) > threshold) + if (to_sq(move) == recaptureSquare) return move; } break;