X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=901aa60e5625c766b797fd88d4dec2888b24ac69;hp=0dd44bbd8db54925e035728bea470075fe5004ae;hb=337ec0f3d0b402782c3704cc251c209393047dd9;hpb=e2e249eabd2493e2bb9e5e017aafaac074a706ef diff --git a/src/movepick.cpp b/src/movepick.cpp index 0dd44bbd..901aa60e 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -23,7 +23,6 @@ //// Includes //// -#include #include #include "history.h" @@ -53,7 +52,7 @@ namespace { CACHE_LINE_ALIGNMENT const uint8_t MainSearchPhaseTable[] = { PH_TT_MOVES, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP}; - const uint8_t EvasionsPhaseTable[] = { PH_EVASIONS, PH_STOP}; + const uint8_t EvasionsPhaseTable[] = { PH_TT_MOVES, PH_EVASIONS, PH_STOP}; const uint8_t QsearchWithChecksPhaseTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_QCHECKS, PH_STOP}; const uint8_t QsearchWithoutChecksPhaseTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_STOP}; } @@ -75,10 +74,11 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss) : pos(p), H(h) { int searchTT = ttm; ttMoves[0].move = ttm; - finished = false; lastBadCapture = badCaptures; - if (ss) + pinned = p.pinned_pieces(pos.side_to_move()); + + if (ss && !p.is_check()) { ttMoves[1].move = (ss->mateKiller == ttm)? MOVE_NONE : ss->mateKiller; searchTT |= ttMoves[1].move; @@ -87,21 +87,24 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, } else ttMoves[1].move = killers[0].move = killers[1].move = MOVE_NONE; - Color us = pos.side_to_move(); - - dc = p.discovered_check_candidates(us); - pinned = p.pinned_pieces(us); - if (p.is_check()) phasePtr = EvasionsPhaseTable; else if (d > Depth(0)) - phasePtr = MainSearchPhaseTable + !searchTT; + phasePtr = MainSearchPhaseTable; else if (d == Depth(0)) - phasePtr = QsearchWithChecksPhaseTable + !searchTT; + phasePtr = QsearchWithChecksPhaseTable; else - phasePtr = QsearchWithoutChecksPhaseTable + !searchTT; + { + phasePtr = QsearchWithoutChecksPhaseTable; - phasePtr--; + // 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 != MOVE_NONE && !pos.move_is_capture_or_promotion(ttm)) + searchTT = ttMoves[0].move = MOVE_NONE; + } + + phasePtr += !searchTT - 1; go_next_phase(); } @@ -123,7 +126,6 @@ void MovePicker::go_next_phase() { case PH_GOOD_CAPTURES: lastMove = generate_captures(pos, moves); score_captures(); - std::stable_sort(moves, lastMove); return; case PH_KILLERS: @@ -134,7 +136,7 @@ void MovePicker::go_next_phase() { case PH_NONCAPTURES: lastMove = generate_noncaptures(pos, moves); score_noncaptures(); - std::stable_sort(moves, lastMove); + sort_moves(moves, lastMove); return; case PH_BAD_CAPTURES: @@ -142,29 +144,26 @@ void MovePicker::go_next_phase() { // to get SEE move ordering. curMove = badCaptures; lastMove = lastBadCapture; - std::stable_sort(badCaptures, lastMove); return; case PH_EVASIONS: assert(pos.is_check()); - lastMove = generate_evasions(pos, moves, pinned); - score_evasions(); - std::stable_sort(moves, lastMove); + lastMove = generate_evasions(pos, moves); + score_evasions_or_checks(); return; case PH_QCAPTURES: lastMove = generate_captures(pos, moves); score_captures(); - std::stable_sort(moves, lastMove); return; case PH_QCHECKS: - // Perhaps we should order moves move here? FIXME - lastMove = generate_non_capture_checks(pos, moves, dc); + lastMove = generate_non_capture_checks(pos, moves); + score_evasions_or_checks(); return; case PH_STOP: - lastMove = curMove + 1; // hack to be friendly for get_next_move() + lastMove = curMove + 1; // Avoids another go_next_phase() call return; default: @@ -202,8 +201,8 @@ void MovePicker::score_captures() { if (move_is_promotion(m)) cur->score = QueenValueMidgame; else - cur->score = int(pos.midgame_value_of_piece_on(move_to(m))) - -int(pos.type_of_piece_on(move_from(m))); + cur->score = pos.midgame_value_of_piece_on(move_to(m)) + - pos.type_of_piece_on(move_from(m)); } } @@ -214,7 +213,6 @@ void MovePicker::score_noncaptures() { Move m; Piece piece; Square from, to; - int hs; for (MoveStack* cur = moves; cur != lastMove; cur++) { @@ -222,31 +220,31 @@ void MovePicker::score_noncaptures() { from = move_from(m); to = move_to(m); piece = pos.piece_on(from); - hs = H.move_ordering_score(piece, to); - - // Ensure history is always preferred to pst - if (hs > 0) - hs += 1000; - - // pst based scoring - cur->score = hs + pos.pst_delta(piece, from, to); + cur->score = H.move_ordering_score(piece, to); } } -void MovePicker::score_evasions() { - +void MovePicker::score_evasions_or_checks() { + // Try good captures ordered by MVV/LVA, then non-captures if + // destination square is not under attack, ordered by history + // value, and at the end bad-captures and non-captures with a + // negative SEE. This last group is ordered by the SEE score. Move m; + int seeScore; + + // Skip if we don't have at least two moves to order + if (lastMove < moves + 2) + return; for (MoveStack* cur = moves; cur != lastMove; cur++) { m = cur->move; - if (m == ttMoves[0].move) - cur->score = 2 * HistoryMax; - else if (!pos.square_is_empty(move_to(m))) - { - int seeScore = pos.see(m); - cur->score = seeScore + (seeScore >= 0 ? HistoryMax : 0); - } else + if ((seeScore = pos.see_sign(m)) < 0) + cur->score = seeScore; + else if (pos.move_is_capture(m)) + cur->score = pos.midgame_value_of_piece_on(move_to(m)) + - pos.type_of_piece_on(move_from(m)) + HistoryMax; + else cur->score = H.move_ordering_score(pos.piece_on(move_from(m)), move_to(m)); } } @@ -256,29 +254,28 @@ void MovePicker::score_evasions() { /// are no more moves left. /// It picks the move with the biggest score from a list of generated moves taking /// care not to return the tt move if has already been searched previously. +/// Note that this function is not thread safe so should be lock protected by +/// caller when accessed through a shared MovePicker object. Move MovePicker::get_next_move() { - assert(!pos.is_check() || *phasePtr == PH_EVASIONS || *phasePtr == PH_STOP); - assert( pos.is_check() || *phasePtr != PH_EVASIONS); - Move move; while (true) { while (curMove != lastMove) { - move = (curMove++)->move; - switch (phase) { case PH_TT_MOVES: + move = (curMove++)->move; if ( move != MOVE_NONE && move_is_legal(pos, move, pinned)) return move; break; case PH_GOOD_CAPTURES: + move = pick_best(curMove++, lastMove).move; if ( move != ttMoves[0].move && move != ttMoves[1].move && pos.pl_move_is_legal(move, pinned)) @@ -298,6 +295,7 @@ Move MovePicker::get_next_move() { break; case PH_KILLERS: + move = (curMove++)->move; if ( move != MOVE_NONE && move != ttMoves[0].move && move != ttMoves[1].move @@ -307,6 +305,7 @@ Move MovePicker::get_next_move() { break; case PH_NONCAPTURES: + move = (curMove++)->move; if ( move != ttMoves[0].move && move != ttMoves[1].move && move != killers[0].move @@ -315,13 +314,20 @@ Move MovePicker::get_next_move() { return move; break; - case PH_EVASIONS: case PH_BAD_CAPTURES: + move = pick_best(curMove++, lastMove).move; return move; + case PH_EVASIONS: case PH_QCAPTURES: + move = pick_best(curMove++, lastMove).move; + if ( move != ttMoves[0].move + && pos.pl_move_is_legal(move, pinned)) + return move; + break; + case PH_QCHECKS: - // Maybe postpone the legality check until after futility pruning? + move = (curMove++)->move; if ( move != ttMoves[0].move && pos.pl_move_is_legal(move, pinned)) return move; @@ -339,21 +345,3 @@ Move MovePicker::get_next_move() { } } -/// A variant of get_next_move() which takes a lock as a parameter, used to -/// prevent multiple threads from picking the same move at a split point. - -Move MovePicker::get_next_move(Lock &lock) { - - lock_grab(&lock); - if (finished) - { - lock_release(&lock); - return MOVE_NONE; - } - Move m = get_next_move(); - if (m == MOVE_NONE) - finished = true; - - lock_release(&lock); - return m; -}