X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=264d941f602b45368c5871afa87e6a6d16691da0;hp=f4f475fb18baa75d7cdb4535723d455daf14be4f;hb=9f626725aeb770a38be093a9a47a461053cf7008;hpb=c8af7a867e91e833f76b564f6f430c96829760bc diff --git a/src/movepick.cpp b/src/movepick.cpp index f4f475fb..264d941f 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) 2008-2009 Marco Costalba + Copyright (C) 2008-2010 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 @@ -51,10 +51,10 @@ 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_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}; + const int MainSearchPhaseTable[] = { PH_TT_MOVES, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP}; + const int EvasionsPhaseTable[] = { PH_TT_MOVES, PH_EVASIONS, PH_STOP}; + const int QsearchWithChecksPhaseTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_QCHECKS, PH_STOP}; + const int QsearchWithoutChecksPhaseTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_STOP}; } @@ -70,17 +70,18 @@ namespace { /// search captures, promotions and some checks) and about how important good /// move ordering is at the current node. -MovePicker::MovePicker(const Position& p, Move ttm, Depth d, - const History& h, SearchStack* ss) : pos(p), H(h) { +MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h, + SearchStack* ss, Value beta) : pos(p), H(h) { int searchTT = ttm; ttMoves[0].move = ttm; - lastBadCapture = badCaptures; + badCaptureThreshold = 0; + badCaptures = moves + MOVES_MAX; pinned = p.pinned_pieces(pos.side_to_move()); if (ss && !p.is_check()) { - ttMoves[1].move = (ss->mateKiller == ttm)? MOVE_NONE : ss->mateKiller; + ttMoves[1].move = (ss->mateKiller == ttm) ? MOVE_NONE : ss->mateKiller; searchTT |= ttMoves[1].move; killers[0].move = ss->killers[0]; killers[1].move = ss->killers[1]; @@ -89,14 +90,29 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, if (p.is_check()) phasePtr = EvasionsPhaseTable; - else if (d > Depth(0)) + else if (d > DEPTH_ZERO) + { + // Consider sligtly negative captures as good if at low + // depth and far from beta. + if (ss && ss->eval < beta - PawnValueMidgame && d < 3 * ONE_PLY) + badCaptureThreshold = -PawnValueMidgame; + phasePtr = MainSearchPhaseTable; - else if (d == Depth(0)) + } + else if (d == DEPTH_ZERO) phasePtr = QsearchWithChecksPhaseTable; else + { phasePtr = QsearchWithoutChecksPhaseTable; - phasePtr += !searchTT - 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 != MOVE_NONE && !pos.move_is_capture_or_promotion(ttm)) + searchTT = ttMoves[0].move = MOVE_NONE; + } + + phasePtr += int(!searchTT) - 1; go_next_phase(); } @@ -128,14 +144,14 @@ void MovePicker::go_next_phase() { case PH_NONCAPTURES: lastMove = generate_noncaptures(pos, moves); score_noncaptures(); - sort_moves(moves, lastMove); + sort_moves(moves, lastMove, &lastGoodNonCapture); return; case PH_BAD_CAPTURES: - // Bad captures SEE value is already calculated so just sort them - // to get SEE move ordering. + // Bad captures SEE value is already calculated so just pick + // them in order to get SEE move ordering. curMove = badCaptures; - lastMove = lastBadCapture; + lastMove = moves + MOVES_MAX; return; case PH_EVASIONS: @@ -150,7 +166,6 @@ void MovePicker::go_next_phase() { return; case PH_QCHECKS: - // Perhaps we should order moves move here? FIXME lastMove = generate_non_capture_checks(pos, moves); return; @@ -205,7 +220,6 @@ void MovePicker::score_noncaptures() { Move m; Piece piece; Square from, to; - int hs; for (MoveStack* cur = moves; cur != lastMove; cur++) { @@ -213,14 +227,7 @@ 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 + mg_value(pos.pst_delta(piece, from, to)); + cur->score = H.value(piece, to) + H.gain(piece, to); } } @@ -232,16 +239,20 @@ void MovePicker::score_evasions() { 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 ((seeScore = pos.see_sign(m)) < 0) - cur->score = seeScore; + cur->score = seeScore - HistoryMax; // Be sure are at the bottom 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)); + cur->score = H.value(pos.piece_on(move_from(m)), move_to(m)); } } @@ -250,6 +261,8 @@ 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() { @@ -276,29 +289,32 @@ Move MovePicker::get_next_move() { { // Check for a non negative SEE now int seeValue = pos.see_sign(move); - if (seeValue >= 0) + if (seeValue >= badCaptureThreshold) return move; - // Losing capture, move it to the badCaptures[] array, note + // Losing capture, move it to the tail of the array, note // that move has now been already checked for legality. - assert(int(lastBadCapture - badCaptures) < 63); - lastBadCapture->move = move; - lastBadCapture->score = seeValue; - lastBadCapture++; + (--badCaptures)->move = move; + badCaptures->score = seeValue; } break; case PH_KILLERS: move = (curMove++)->move; if ( move != MOVE_NONE + && move_is_legal(pos, move, pinned) && move != ttMoves[0].move && move != ttMoves[1].move - && move_is_legal(pos, move, pinned) && !pos.move_is_capture(move)) return move; break; case PH_NONCAPTURES: + + // Sort negative scored moves only when we get there + if (curMove == lastGoodNonCapture) + insertion_sort(lastGoodNonCapture, lastMove); + move = (curMove++)->move; if ( move != ttMoves[0].move && move != ttMoves[1].move @@ -339,17 +355,3 @@ 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); - - // Note that it is safe to call many times - // get_next_move() when phase == PH_STOP - Move m = get_next_move(); - - lock_release(&lock); - return m; -}