X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=27245ec7c73904dd5c32a7cced6b7b4d461561d3;hp=3f0837d94db2f1d95843a65a6244a38df998909d;hb=e56e5045dd48489a304e2b46d5461361b205b237;hpb=7ddbcf7e87a0b0c882d8d33841bd7ae53969619d diff --git a/src/movepick.cpp b/src/movepick.cpp index 3f0837d9..27245ec7 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -1,7 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, 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 @@ -35,7 +35,7 @@ namespace { STOP }; - // Our insertion sort, which is guaranteed (and also needed) to be stable + // Our insertion sort, which is guaranteed to be stable, as it should be void insertion_sort(ExtMove* begin, ExtMove* end) { ExtMove tmp, *p, *q; @@ -49,19 +49,16 @@ namespace { } } - // Unary predicate used by std::partition to split positive values from remaining - // ones so as to sort the two sets separately, with the second sort delayed. - inline bool has_positive_value(const ExtMove& ms) { return ms.value > 0; } - - // Picks 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. possible captures. - inline ExtMove* pick_best(ExtMove* begin, ExtMove* end) + // 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) { std::swap(*begin, *std::max_element(begin, end)); - return begin; + return *begin; } -} + +} // namespace /// Constructors of the MovePicker class. As arguments we pass information @@ -75,7 +72,6 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& assert(d > DEPTH_ZERO); - cur = end = moves; endBadCaptures = moves + MAX_MOVES - 1; countermoves = cm; followupmoves = fm; @@ -88,11 +84,11 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& stage = MAIN_SEARCH; ttMove = (ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE); - end += (ttMove != MOVE_NONE); + endMoves += (ttMove != MOVE_NONE); } MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h, - Square s) : pos(p), history(h), cur(moves), end(moves) { + Square s) : pos(p), history(h) { assert(d <= DEPTH_ZERO); @@ -103,15 +99,8 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& stage = QSEARCH_0; else if (d > DEPTH_QS_RECAPTURES) - { stage = QSEARCH_1; - // Skip TT move if is not a capture or a promotion. This avoids qsearch - // tree explosion due to a possible perpetual check or similar rare cases - // when TT table is full. - if (ttm && !pos.capture_or_promotion(ttm)) - ttm = MOVE_NONE; - } else { stage = RECAPTURE; @@ -120,11 +109,11 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& } ttMove = (ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE); - end += (ttMove != MOVE_NONE); + endMoves += (ttMove != MOVE_NONE); } MovePicker::MovePicker(const Position& p, Move ttm, const HistoryStats& h, PieceType pt) - : pos(p), history(h), cur(moves), end(moves) { + : pos(p), history(h) { assert(!pos.checkers()); @@ -138,7 +127,7 @@ MovePicker::MovePicker(const Position& p, Move ttm, const HistoryStats& h, Piece if (ttMove && (!pos.capture(ttMove) || pos.see(ttMove) <= captureThreshold)) ttMove = MOVE_NONE; - end += (ttMove != MOVE_NONE); + endMoves += (ttMove != MOVE_NONE); } @@ -159,32 +148,22 @@ void MovePicker::score() { // 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. - Move m; - - for (ExtMove* it = moves; it != end; ++it) - { - m = it->move; - it->value = PieceValue[MG][pos.piece_on(to_sq(m))] - - Value(type_of(pos.moved_piece(m))); - + for (auto& m : *this) if (type_of(m) == ENPASSANT) - it->value += PieceValue[MG][PAWN]; + m.value = PieceValue[MG][PAWN] - Value(PAWN); else if (type_of(m) == PROMOTION) - it->value += PieceValue[MG][promotion_type(m)] - PieceValue[MG][PAWN]; - } + 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))); } template<> void MovePicker::score() { - - Move m; - - for (ExtMove* it = moves; it != end; ++it) - { - m = it->move; - it->value = history[pos.moved_piece(m)][to_sq(m)]; - } + for (auto& m : *this) + m.value = history[pos.moved_piece(m)][to_sq(m)]; } template<> @@ -192,21 +171,17 @@ 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. - Move m; Value see; - for (ExtMove* it = moves; it != end; ++it) - { - m = it->move; + for (auto& m : *this) if ((see = pos.see_sign(m)) < VALUE_ZERO) - it->value = see - HistoryStats::Max; // At the bottom + m.value = see - HistoryStats::Max; // At the bottom else if (pos.capture(m)) - it->value = PieceValue[MG][pos.piece_on(to_sq(m))] - - Value(type_of(pos.moved_piece(m))) + HistoryStats::Max; + m.value = PieceValue[MG][pos.piece_on(to_sq(m))] + - Value(type_of(pos.moved_piece(m))) + HistoryStats::Max; else - it->value = history[pos.moved_piece(m)][to_sq(m)]; - } + m.value = history[pos.moved_piece(m)][to_sq(m)]; } @@ -220,72 +195,58 @@ void MovePicker::generate_next_stage() { switch (++stage) { case CAPTURES_S1: case CAPTURES_S3: case CAPTURES_S4: case CAPTURES_S5: case CAPTURES_S6: - end = generate(pos, moves); + endMoves = generate(pos, moves); score(); - return; + break; case KILLERS_S1: cur = killers; - end = cur + 2; - - killers[0].move = ss->killers[0]; - killers[1].move = ss->killers[1]; - killers[2].move = killers[3].move = MOVE_NONE; - killers[4].move = killers[5].move = MOVE_NONE; - - // Please note that following code is racy and could yield to rare (less - // than 1 out of a million) duplicated entries in SMP case. This is harmless. - - // Be sure countermoves are different from killers - for (int i = 0; i < 2; ++i) - if ( countermoves[i] != (cur+0)->move - && countermoves[i] != (cur+1)->move) - (end++)->move = countermoves[i]; - - // Be sure followupmoves are different from killers and countermoves - for (int i = 0; i < 2; ++i) - if ( followupmoves[i] != (cur+0)->move - && followupmoves[i] != (cur+1)->move - && followupmoves[i] != (cur+2)->move - && followupmoves[i] != (cur+3)->move) - (end++)->move = followupmoves[i]; - return; + endMoves = cur + 6; + killers[0] = ss->killers[0]; + killers[1] = ss->killers[1]; + killers[2] = countermoves[0]; + killers[3] = countermoves[1]; + killers[4] = followupmoves[0]; + killers[5] = followupmoves[1]; + break; case QUIETS_1_S1: - endQuiets = end = generate(pos, moves); + endQuiets = endMoves = generate(pos, moves); score(); - end = std::partition(cur, end, has_positive_value); - insertion_sort(cur, end); - return; + endMoves = std::partition(cur, endMoves, [](const ExtMove& m) { return m.value > VALUE_ZERO; }); + insertion_sort(cur, endMoves); + break; case QUIETS_2_S1: - cur = end; - end = endQuiets; + cur = endMoves; + endMoves = endQuiets; if (depth >= 3 * ONE_PLY) - insertion_sort(cur, end); - return; + insertion_sort(cur, endMoves); + break; case BAD_CAPTURES_S1: // Just pick them in reverse order to get MVV/LVA ordering cur = moves + MAX_MOVES - 1; - end = endBadCaptures; - return; + endMoves = endBadCaptures; + break; case EVASIONS_S2: - end = generate(pos, moves); - if (end > moves + 1) + endMoves = generate(pos, moves); + if (endMoves - moves > 1) score(); - return; + break; case QUIET_CHECKS_S3: - end = generate(pos, moves); - return; + endMoves = generate(pos, moves); + break; case EVASION: case QSEARCH_0: case QSEARCH_1: case PROBCUT: case RECAPTURE: stage = STOP; + /* Fall through */ + case STOP: - end = cur + 1; // Avoid another next_phase() call - return; + endMoves = cur + 1; // Avoid another next_phase() call + break; default: assert(false); @@ -304,7 +265,7 @@ Move MovePicker::next_move() { while (true) { - while (cur == end) + while (cur == endMoves) generate_next_stage(); switch (stage) { @@ -314,61 +275,67 @@ Move MovePicker::next_move() { return ttMove; case CAPTURES_S1: - move = pick_best(cur++, end)->move; + move = pick_best(cur++, endMoves); if (move != ttMove) { if (pos.see_sign(move) >= VALUE_ZERO) return move; // Losing capture, move it to the tail of the array - (endBadCaptures--)->move = move; + *endBadCaptures-- = move; } break; case KILLERS_S1: - move = (cur++)->move; + move = *cur++; if ( move != MOVE_NONE && move != ttMove && pos.pseudo_legal(move) && !pos.capture(move)) + { + for (int i = 0; i < cur - 1 - killers; i++) // Skip duplicated + if (move == killers[i]) + goto skip; return move; + } + skip: break; case QUIETS_1_S1: case QUIETS_2_S1: - move = (cur++)->move; + move = *cur++; if ( move != ttMove - && move != killers[0].move - && move != killers[1].move - && move != killers[2].move - && move != killers[3].move - && move != killers[4].move - && move != killers[5].move) + && move != killers[0] + && move != killers[1] + && move != killers[2] + && move != killers[3] + && move != killers[4] + && move != killers[5]) return move; break; case BAD_CAPTURES_S1: - return (cur--)->move; + return *cur--; case EVASIONS_S2: case CAPTURES_S3: case CAPTURES_S4: - move = pick_best(cur++, end)->move; + move = pick_best(cur++, endMoves); if (move != ttMove) return move; break; case CAPTURES_S5: - move = pick_best(cur++, end)->move; + move = pick_best(cur++, endMoves); if (move != ttMove && pos.see(move) > captureThreshold) return move; break; case CAPTURES_S6: - move = pick_best(cur++, end)->move; + move = pick_best(cur++, endMoves); if (to_sq(move) == recaptureSquare) return move; break; case QUIET_CHECKS_S3: - move = (cur++)->move; + move = *cur++; if (move != ttMove) return move; break;