X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=45d989c91a80bdb0755a3516f19b64e29668b844;hp=a18c46923b60742160816fddb3d9c8ff2734dc35;hb=9e4befe3f1ea324bece88aee2e97b38659411c52;hpb=bbf7a94d76339837a6e8925ded1ea231d51e773d diff --git a/src/movepick.cpp b/src/movepick.cpp index a18c4692..45d989c9 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -1,17 +1,19 @@ /* - Glaurung, a UCI chess playing engine. - Copyright (C) 2004-2008 Tord Romstad + 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 - Glaurung is free software: you can redistribute it and/or modify + Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. - - Glaurung is distributed in the hope that it will be useful, + + + Stockfish is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. - + You should have received a copy of the GNU General Public License along with this program. If not, see . */ @@ -21,9 +23,11 @@ //// Includes //// +#include #include #include "history.h" +#include "evaluate.h" #include "movegen.h" #include "movepick.h" #include "search.h" @@ -38,16 +42,15 @@ namespace { /// Variables - int MainSearchPhaseIndex; - int EvasionsPhaseIndex; - int QsearchWithChecksPhaseIndex; - int QsearchWithoutChecksPhaseIndex; - + CACHE_LINE_ALIGNMENT + const MovegenPhaseT MainSearchPhaseTable[] = { PH_NULL_MOVE, PH_TT_MOVES, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP}; + const MovegenPhaseT MainSearchNoNullPhaseTable[] = { PH_TT_MOVES, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP}; + const MovegenPhaseT LowSearchPhaseTable[] = { PH_TT_MOVES, PH_GOOD_CAPTURES, PH_NULL_MOVE, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP}; + const MovegenPhaseT EvasionsPhaseTable[] = { PH_EVASIONS, PH_STOP}; + const MovegenPhaseT QsearchWithChecksPhaseTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_QCHECKS, PH_STOP}; + const MovegenPhaseT QsearchWithoutChecksPhaseTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_STOP}; } -// Static array definition -MovePicker::MovegenPhase MovePicker::PhaseTable[32]; - //// //// Functions @@ -61,419 +64,302 @@ MovePicker::MovegenPhase MovePicker::PhaseTable[32]; /// search captures, promotions and some checks) and about how important good /// move ordering is at the current node. -MovePicker::MovePicker(Position &p, bool pvnode, Move ttm, Move mk, - Move k1, Move k2, Depth dpth) { - pos = &p; - pvNode = pvnode; - ttMove = ttm; - mateKiller = (mk == ttm)? MOVE_NONE : mk; - killer1 = k1; - killer2 = k2; - depth = dpth; - movesPicked = 0; - numOfMoves = 0; - numOfBadCaptures = 0; - dc = p.discovered_check_candidates(p.side_to_move()); - - if(p.is_check()) - phaseIndex = EvasionsPhaseIndex; - else if(depth > Depth(0)) - phaseIndex = MainSearchPhaseIndex; - else if(depth == Depth(0)) - phaseIndex = QsearchWithChecksPhaseIndex; - else - phaseIndex = QsearchWithoutChecksPhaseIndex; - - pinned = p.pinned_pieces(p.side_to_move()); +MovePicker::MovePicker(const Position& p, Move ttm, Depth d, + const History& h, SearchStack* ss, bool useNullMove) : pos(p), H(h) { + ttMoves[0] = ttm; + if (ss) + { + ttMoves[1] = (ss->mateKiller == ttm)? MOVE_NONE : ss->mateKiller; + killers[0] = ss->killers[0]; + killers[1] = ss->killers[1]; + } else + ttMoves[1] = killers[0] = killers[1] = MOVE_NONE; + numOfBadCaptures = 0; finished = false; -} + Color us = pos.side_to_move(); -/// MovePicker::get_next_move() is the most important method of the MovePicker -/// class. It returns a new legal move every time it is called, until there -/// are no more moves left of the types we are interested in. + dc = p.discovered_check_candidates(us); + pinned = p.pinned_pieces(us); -Move MovePicker::get_next_move() { - Move move; - - while(true) { - // If we already have a list of generated moves, pick the best move from - // the list, and return it: - move = this->pick_move_from_list(); - if(move != MOVE_NONE) { - assert(move_is_ok(move)); - return move; - } - - // Next phase: - phaseIndex++; - switch(PhaseTable[phaseIndex]) { - - case PH_TT_MOVE: - if(ttMove != MOVE_NONE) { - assert(move_is_ok(ttMove)); - Move m = generate_move_if_legal(*pos, ttMove, pinned); - if(m != MOVE_NONE) { - assert(m == ttMove); - return m; - } - } - break; - - case PH_MATE_KILLER: - if(mateKiller != MOVE_NONE) { - assert(move_is_ok(mateKiller)); - Move m = generate_move_if_legal(*pos, mateKiller, pinned); - if(m != MOVE_NONE) { - assert(m == mateKiller); - return m; - } - } - break; + if (p.is_check()) + phasePtr = EvasionsPhaseTable; + else if (d >= Depth(3 * OnePly)) + phasePtr = useNullMove ? MainSearchPhaseTable : MainSearchNoNullPhaseTable; + else if (d > Depth(0)) + phasePtr = useNullMove ? LowSearchPhaseTable : MainSearchNoNullPhaseTable; + else if (d == Depth(0)) + phasePtr = QsearchWithChecksPhaseTable; + else + phasePtr = QsearchWithoutChecksPhaseTable; - case PH_GOOD_CAPTURES: - // pinned = pos->pinned_pieces(pos->side_to_move()); - numOfMoves = generate_captures(*pos, moves); - this->score_captures(); - movesPicked = 0; - break; + phasePtr--; + go_next_phase(); +} - case PH_BAD_CAPTURES: - badCapturesPicked = 0; - break; - case PH_NONCAPTURES: - numOfMoves = generate_noncaptures(*pos, moves); - this->score_noncaptures(); - movesPicked = 0; - break; +/// MovePicker::go_next_phase() generates, scores and sorts the next bunch +/// of moves when there are no more moves to try for the current phase. - case PH_EVASIONS: - assert(pos->is_check()); - // pinned = pos->pinned_pieces(pos->side_to_move()); - numOfMoves = generate_evasions(*pos, moves); - this->score_evasions(); - movesPicked = 0; - break; +void MovePicker::go_next_phase() { - case PH_QCAPTURES: - // pinned = pos->pinned_pieces(pos->side_to_move()); - numOfMoves = generate_captures(*pos, moves); - this->score_qcaptures(); - movesPicked = 0; - break; + curMove = moves; + phase = *(++phasePtr); + switch (phase) { - case PH_QCHECKS: - numOfMoves = generate_checks(*pos, moves, dc); + case PH_NULL_MOVE: + case PH_TT_MOVES: movesPicked = 0; - break; - - case PH_STOP: - return MOVE_NONE; + return; - default: - assert(false); - return MOVE_NONE; - } - } + case PH_GOOD_CAPTURES: + lastMove = generate_captures(pos, moves); + score_captures(); + std::sort(moves, lastMove); + return; - assert(false); + case PH_KILLERS: + movesPicked = 0; + return; - return MOVE_NONE; -} + case PH_NONCAPTURES: + lastMove = generate_noncaptures(pos, moves); + score_noncaptures(); + std::sort(moves, lastMove); + return; + case PH_BAD_CAPTURES: + // Bad captures SEE value is already calculated so just sort them + // to get SEE move ordering. + curMove = badCaptures; + lastMove = badCaptures + numOfBadCaptures; + std::sort(badCaptures, lastMove); + return; -/// 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. + case PH_EVASIONS: + assert(pos.is_check()); + lastMove = generate_evasions(pos, moves, pinned); + score_evasions(); + std::sort(moves, lastMove); + return; -Move MovePicker::get_next_move(Lock &lock) { - Move m; + case PH_QCAPTURES: + lastMove = generate_captures(pos, moves); + score_captures(); + std::sort(moves, lastMove); + return; - lock_grab(&lock); - if(finished) { - lock_release(&lock); - return MOVE_NONE; - } - m = this->get_next_move(); - if(m == MOVE_NONE) - finished = true; - lock_release(&lock); - - return m; -} + case PH_QCHECKS: + // Perhaps we should order moves move here? FIXME + lastMove = generate_non_capture_checks(pos, moves, dc); + return; - -/// MovePicker::number_of_moves() simply returns the numOfMoves member -/// variable. It is intended to be used in positions where the side to move -/// is in check, for detecting checkmates or situations where there is only -/// a single reply to check. + case PH_STOP: + return; -int MovePicker::number_of_moves() const { - return numOfMoves; + default: + assert(false); + return; + } } -/// MovePicker::score_captures(), MovePicker::score_noncaptures(), -/// MovePicker::score_evasions() and MovePicker::score_qcaptures() assign a -/// numerical move ordering score to each move in a move list. The moves -/// with highest scores will be picked first by -/// MovePicker::pick_move_from_list(). +/// MovePicker::score_captures(), MovePicker::score_noncaptures() and +/// MovePicker::score_evasions() assign a numerical move ordering score +/// to each move in a move list. The moves with highest scores will be +/// picked first by get_next_move(). void MovePicker::score_captures() { // Winning and equal captures in the main search are ordered by MVV/LVA. // Suprisingly, this appears to perform slightly better than SEE based - // move ordering. The reason is probably that in a position with a winning + // move ordering. The reason is probably that in a position with a winning // capture, capturing a more valuable (but sufficiently defended) piece - // first usually doesn't hurt. The opponent will have to recapture, and + // first usually doesn't hurt. The opponent will have to recapture, and // the hanging piece will still be hanging (except in the unusual cases - // where it is possible to recapture with the hanging piece). Exchanging + // where it is possible to recapture with the hanging piece). Exchanging // big pieces before capturing a hanging piece probably helps to reduce // the subtree size. - for(int i = 0; i < numOfMoves; i++) { - int seeValue = pos->see(moves[i].move); - if(seeValue >= 0) { - if(move_promotion(moves[i].move)) - moves[i].score = QueenValueMidgame; - else - moves[i].score = - int(pos->midgame_value_of_piece_on(move_to(moves[i].move))) - - int(pos->type_of_piece_on(move_from(moves[i].move))); - } - else - moves[i].score = seeValue; - + // In main search we want to push captures with negative SEE values to + // badCaptures[] array, but instead of doing it now we delay till when + // the move has been picked up in pick_move_from_list(), this way we save + // some SEE calls in case we get a cutoff (idea from Pablo Vazquez). + Move m; + + // Use MVV/LVA ordering + for (MoveStack* cur = moves; cur != lastMove; cur++) + { + m = cur->move; + 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))); } } void MovePicker::score_noncaptures() { - for(int i = 0; i < numOfMoves; i++) { - Move m = moves[i].move; - if(m == killer1) - moves[i].score = HistoryMax + 2; - else if(m == killer2) - moves[i].score = HistoryMax + 1; - else - moves[i].score = H.move_ordering_score(pos->piece_on(move_from(m)), m); + // First score by history, when no history is available then use + // piece/square tables values. This seems to be better then a + // random choice when we don't have an history for any move. + Piece piece; + Square from, to; + int hs; + + for (MoveStack* cur = moves; cur != lastMove; cur++) + { + from = move_from(cur->move); + to = move_to(cur->move); + 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); } } void MovePicker::score_evasions() { - for(int i = 0; i < numOfMoves; i++) { - Move m = moves[i].move; - if(m == ttMove) - moves[i].score = 2*HistoryMax; - else if(!pos->square_is_empty(move_to(m))) { - int seeScore = pos->see(m); - moves[i].score = (seeScore >= 0)? seeScore + HistoryMax : seeScore; - } - else - moves[i].score = H.move_ordering_score(pos->piece_on(move_from(m)), m); - } -} -void MovePicker::score_qcaptures() { - // Use MVV/LVA ordering. - for(int i = 0; i < numOfMoves; i++) { - Move m = moves[i].move; - if(move_promotion(m)) - moves[i].score = QueenValueMidgame; - else - moves[i].score = - int(pos->midgame_value_of_piece_on(move_to(m))) - - int(pos->midgame_value_of_piece_on(move_to(m))) / 64; + for (MoveStack* cur = moves; cur != lastMove; cur++) + { + Move m = cur->move; + if (m == ttMoves[0]) + cur->score = 2*HistoryMax; + else if (!pos.square_is_empty(move_to(m))) + { + int seeScore = pos.see(m); + cur->score = (seeScore >= 0)? seeScore + HistoryMax : seeScore; + } else + cur->score = H.move_ordering_score(pos.piece_on(move_from(m)), move_to(m)); } } +/// MovePicker::get_next_move() is the most important method of the MovePicker +/// class. It returns a new legal move every time it is called, until there +/// 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 that has already been serched previously. -/// MovePicker::pick_move_from_list() picks the move with the biggest score -/// from a list of generated moves (moves[] or badCaptures[], depending on -/// the current move generation phase). It takes care not to return the -/// transposition table move if that has already been serched previously. -/// While picking captures in the PH_GOOD_CAPTURES phase (i.e. while picking -/// non-losing captures in the main search), it moves all captures with -/// negative SEE values to the badCaptures[] array. +Move MovePicker::get_next_move() { -Move MovePicker::pick_move_from_list() { - int bestScore = -10000000; - int bestIndex; - Move move; + assert(!pos.is_check() || *phasePtr == PH_EVASIONS || *phasePtr == PH_STOP); + assert( pos.is_check() || *phasePtr != PH_EVASIONS); - switch(PhaseTable[phaseIndex]) { + while (true) + { + switch (phase) { - case PH_GOOD_CAPTURES: - assert(!pos->is_check()); - assert(movesPicked >= 0); - while(movesPicked < numOfMoves) { - bestScore = -10000000; - bestIndex = -1; - for(int i = movesPicked; i < numOfMoves; i++) { - if(moves[i].score < 0) { - // Losing capture, move it to the badCaptures[] array - assert(numOfBadCaptures < 63); - badCaptures[numOfBadCaptures++] = moves[i]; - moves[i--] = moves[--numOfMoves]; - } - else if(moves[i].score > bestScore) { - bestIndex = i; - bestScore = moves[i].score; - } - } - if(bestIndex != -1) { // Found a good capture - move = moves[bestIndex].move; - moves[bestIndex] = moves[movesPicked++]; - if(move != ttMove && move != mateKiller && - pos->move_is_legal(move, pinned)) - return move; - } - } - break; + case PH_NULL_MOVE: + go_next_phase(); + return MOVE_NULL; - case PH_NONCAPTURES: - assert(!pos->is_check()); - assert(movesPicked >= 0); - while(movesPicked < numOfMoves) { - bestScore = -10000000; - - // If this is a PV node or we have only picked a few moves, scan - // the entire move list for the best move. If many moves have already - // been searched and it is not a PV node, we are probably failing low - // anyway, so we just pick the first move from the list. - if(pvNode || movesPicked < 12) { - bestIndex = -1; - for(int i = movesPicked; i < numOfMoves; i++) - if(moves[i].score > bestScore) { - bestIndex = i; - bestScore = moves[i].score; + case PH_TT_MOVES: + while (movesPicked < 2) + { + Move move = ttMoves[movesPicked++]; + if ( move != MOVE_NONE + && move_is_legal(pos, move, pinned)) + return move; } - } - else - bestIndex = movesPicked; - - if(bestIndex != -1) { - move = moves[bestIndex].move; - moves[bestIndex] = moves[movesPicked++]; - if(move != ttMove && move != mateKiller && - pos->move_is_legal(move, pinned)) - return move; - } - } - break; - - case PH_EVASIONS: - assert(pos->is_check()); - assert(movesPicked >= 0); - while(movesPicked < numOfMoves) { - bestScore = -10000000; - bestIndex = -1; - for(int i = movesPicked; i < numOfMoves; i++) - if(moves[i].score > bestScore) { - bestIndex = i; - bestScore = moves[i].score; - } - - if(bestIndex != -1) { - move = moves[bestIndex].move; - moves[bestIndex] = moves[movesPicked++]; - return move; - } - } - break; - - case PH_BAD_CAPTURES: - assert(!pos->is_check()); - assert(badCapturesPicked >= 0); - // It's probably a good idea to use SEE move ordering here, instead - // of just picking the first move. FIXME - while(badCapturesPicked < numOfBadCaptures) { - move = badCaptures[badCapturesPicked++].move; - if(move != ttMove && move != mateKiller && - pos->move_is_legal(move, pinned)) - return move; - } - break; - - case PH_QCAPTURES: - assert(!pos->is_check()); - assert(movesPicked >= 0); - while(movesPicked < numOfMoves) { - bestScore = -10000000; - if(movesPicked < 4) { - bestIndex = -1; - for(int i = movesPicked; i < numOfMoves; i++) - if(moves[i].score > bestScore) { - bestIndex = i; - bestScore = moves[i].score; + break; + + case PH_GOOD_CAPTURES: + while (curMove != lastMove) + { + Move move = (curMove++)->move; + if ( move != ttMoves[0] + && move != ttMoves[1] + && pos.pl_move_is_legal(move, pinned)) + { + // Check for a non negative SEE now + int seeValue = pos.see_sign(move); + if (seeValue >= 0) + return move; + + // Losing capture, move it to the badCaptures[] array, note + // that move has now been already checked for legality. + assert(numOfBadCaptures < 63); + badCaptures[numOfBadCaptures].move = move; + badCaptures[numOfBadCaptures++].score = seeValue; + } } - } - else - bestIndex = movesPicked; - - if(bestIndex != -1) { - move = moves[bestIndex].move; - moves[bestIndex] = moves[movesPicked++]; - // Remember to change the line below if we decide to hash the qsearch! - // Maybe also postpone the legality check until after futility pruning? - if(/* move != ttMove && */ pos->move_is_legal(move, pinned)) - return move; - } - } - break; + break; + + case PH_KILLERS: + while (movesPicked < 2) + { + Move move = killers[movesPicked++]; + if ( move != MOVE_NONE + && move != ttMoves[0] + && move != ttMoves[1] + && move_is_legal(pos, move, pinned) + && !pos.move_is_capture(move)) + return move; + } + break; + + case PH_NONCAPTURES: + while (curMove != lastMove) + { + Move move = (curMove++)->move; + if ( move != ttMoves[0] + && move != ttMoves[1] + && move != killers[0] + && move != killers[1] + && pos.pl_move_is_legal(move, pinned)) + return move; + } + break; + + case PH_EVASIONS: + case PH_BAD_CAPTURES: + if (curMove != lastMove) + return (curMove++)->move; + break; + + case PH_QCAPTURES: + case PH_QCHECKS: + while (curMove != lastMove) + { + Move move = (curMove++)->move; + // Maybe postpone the legality check until after futility pruning? + if ( move != ttMoves[0] + && pos.pl_move_is_legal(move, pinned)) + return move; + } + break; - case PH_QCHECKS: - assert(!pos->is_check()); - assert(movesPicked >= 0); - // Perhaps we should do something better than just picking the first - // move here? FIXME - while(movesPicked < numOfMoves) { - move = moves[movesPicked++].move; - // Remember to change the line below if we decide to hash the qsearch! - if(/* move != ttMove && */ pos->move_is_legal(move, pinned)) - return move; - } - break; + case PH_STOP: + return MOVE_NONE; - default: - break; + default: + assert(false); + break; + } + go_next_phase(); } - return MOVE_NONE; } +/// 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; -/// MovePicker::init_phase_table() initializes the PhaseTable[], -/// MainSearchPhaseIndex, EvasionPhaseIndex, QsearchWithChecksPhaseIndex -/// and QsearchWithoutChecksPhaseIndex variables. It is only called once -/// during program startup, and never again while the program is running. - -void MovePicker::init_phase_table() { - int i = 0; - - // Main search - MainSearchPhaseIndex = i - 1; - PhaseTable[i++] = PH_TT_MOVE; - PhaseTable[i++] = PH_MATE_KILLER; - PhaseTable[i++] = PH_GOOD_CAPTURES; - // PH_KILLER_1 and PH_KILLER_2 are not yet used. - // PhaseTable[i++] = PH_KILLER_1; - // PhaseTable[i++] = PH_KILLER_2; - PhaseTable[i++] = PH_NONCAPTURES; - PhaseTable[i++] = PH_BAD_CAPTURES; - PhaseTable[i++] = PH_STOP; - - // Check evasions - EvasionsPhaseIndex = i - 1; - PhaseTable[i++] = PH_EVASIONS; - PhaseTable[i++] = PH_STOP; - - // Quiescence search with checks - QsearchWithChecksPhaseIndex = i - 1; - PhaseTable[i++] = PH_QCAPTURES; - PhaseTable[i++] = PH_QCHECKS; - PhaseTable[i++] = PH_STOP; - - // Quiescence search without checks - QsearchWithoutChecksPhaseIndex = i - 1; - PhaseTable[i++] = PH_QCAPTURES; - PhaseTable[i++] = PH_STOP; + lock_release(&lock); + return m; }