X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=43f30f7709565e22502e6e94438a0aa91ac663d1;hp=4d2d31167ea2db2641c582c545ba3c6c46b1a0fe;hb=75d001adddfaa7a2eb57af99cf6c57a12913d2d1;hpb=58c7a5c4775f7efa333bb2c921583ffba301f6b2 diff --git a/src/movepick.cpp b/src/movepick.cpp index 4d2d3116..43f30f77 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 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 . */ @@ -24,6 +26,7 @@ #include #include "history.h" +#include "evaluate.h" #include "movegen.h" #include "movepick.h" #include "search.h" @@ -38,11 +41,13 @@ namespace { /// Variables - MovePicker::MovegenPhase PhaseTable[32]; + MovePicker::MovegenPhase PhaseTable[32]; int MainSearchPhaseIndex; int EvasionsPhaseIndex; int QsearchWithChecksPhaseIndex; + int QsearchNoCapturesPhaseIndex; int QsearchWithoutChecksPhaseIndex; + int NoMovesPhaseIndex; } @@ -60,29 +65,38 @@ namespace { /// 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; +MovePicker::MovePicker(const Position& p, bool pv, Move ttm, + const SearchStack& ss, Depth d, EvalInfo* ei) : pos(p) { + pvNode = pv; ttMove = ttm; - mateKiller = (mk == ttm)? MOVE_NONE : mk; - killer1 = k1; - killer2 = k2; - depth = dpth; + mateKiller = (ss.mateKiller == ttm)? MOVE_NONE : ss.mateKiller; + killer1 = ss.killers[0]; + killer2 = ss.killers[0]; + depth = d; 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; + + // With EvalInfo we are able to know how many captures are possible before + // generating them. So avoid generating in case we know are zero. + Color us = pos.side_to_move(); + Color them = opposite_color(us); + bool noCaptures = ei + && (ei->attackedBy[us][0] & pos.pieces_of_color(them)) == 0 + && !ei->mi->specialized_eval_exists() + && (pos.ep_square() == SQ_NONE) + && !pos.has_pawn_on_7th(us); + + if (p.is_check()) + phaseIndex = EvasionsPhaseIndex; + else if (depth > Depth(0)) + phaseIndex = MainSearchPhaseIndex; + else if (depth == Depth(0)) + phaseIndex = (noCaptures ? QsearchNoCapturesPhaseIndex : QsearchWithChecksPhaseIndex); else - phaseIndex = QsearchWithoutChecksPhaseIndex; + phaseIndex = (noCaptures ? NoMovesPhaseIndex : QsearchWithoutChecksPhaseIndex); + dc = p.discovered_check_candidates(us); pinned = p.pinned_pieces(p.side_to_move()); finished = false; @@ -94,92 +108,84 @@ MovePicker::MovePicker(Position &p, bool pvnode, Move ttm, Move mk, /// are no more moves left of the types we are interested in. Move MovePicker::get_next_move() { + Move move; - while(true) { + 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; + // the list, and return it. + move = pick_move_from_list(); + if (move != MOVE_NONE) + { + assert(move_is_ok(move)); + return move; } - // Next phase: + // Next phase phaseIndex++; - switch(PhaseTable[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; + if (ttMove != MOVE_NONE) + { + assert(move_is_ok(ttMove)); + if (move_is_legal(pos, ttMove, pinned)) + return ttMove; } - } - break; + 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 (mateKiller != MOVE_NONE) + { + assert(move_is_ok(mateKiller)); + if (move_is_legal(pos, mateKiller, pinned)) + return mateKiller; + } + break; case PH_GOOD_CAPTURES: - // pinned = pos->pinned_pieces(pos->side_to_move()); - numOfMoves = generate_captures(*pos, moves); - this->score_captures(); - movesPicked = 0; - break; + numOfMoves = generate_captures(pos, moves); + score_captures(); + movesPicked = 0; + break; case PH_BAD_CAPTURES: - badCapturesPicked = 0; - break; + badCapturesPicked = 0; + break; case PH_NONCAPTURES: - numOfMoves = generate_noncaptures(*pos, moves); - this->score_noncaptures(); - movesPicked = 0; - break; + numOfMoves = generate_noncaptures(pos, moves); + score_noncaptures(); + movesPicked = 0; + break; 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; + assert(pos.is_check()); + numOfMoves = generate_evasions(pos, moves); + score_evasions(); + movesPicked = 0; + break; case PH_QCAPTURES: - // pinned = pos->pinned_pieces(pos->side_to_move()); - numOfMoves = generate_captures(*pos, moves); - this->score_qcaptures(); - movesPicked = 0; - break; + numOfMoves = generate_captures(pos, moves); + score_qcaptures(); + movesPicked = 0; + break; case PH_QCHECKS: - numOfMoves = generate_checks(*pos, moves, dc); - movesPicked = 0; - break; + numOfMoves = generate_checks(pos, moves, dc); + movesPicked = 0; + break; case PH_STOP: - return MOVE_NONE; + return MOVE_NONE; default: - assert(false); - return MOVE_NONE; + assert(false); + return MOVE_NONE; } } - - assert(false); - - return MOVE_NONE; } @@ -187,37 +193,26 @@ Move MovePicker::get_next_move() { /// prevent multiple threads from picking the same move at a split point. Move MovePicker::get_next_move(Lock &lock) { - Move m; lock_grab(&lock); - if(finished) { - lock_release(&lock); - return MOVE_NONE; + if (finished) + { + lock_release(&lock); + return MOVE_NONE; } - m = this->get_next_move(); - if(m == MOVE_NONE) - finished = true; + Move m = get_next_move(); + if (m == MOVE_NONE) + finished = true; + lock_release(&lock); - return m; } - -/// 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. - -int MovePicker::number_of_moves() const { - return numOfMoves; -} - /// 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(). +/// with highest scores will be picked first by pick_move_from_list(). void MovePicker::score_captures() { // Winning and equal captures in the main search are ordered by MVV/LVA. @@ -226,229 +221,296 @@ void MovePicker::score_captures() { // capture, capturing a more valuable (but sufficiently defended) piece // 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; - + // While scoring captures it moves all captures with negative SEE values + // to the badCaptures[] array. + Move m; + int seeValue; + + for (int i = 0; i < numOfMoves; i++) + { + m = moves[i].move; + seeValue = pos.see(m); + if (seeValue >= 0) + { + if (move_promotion(m)) + moves[i].score = QueenValueMidgame; + else + moves[i].score = int(pos.midgame_value_of_piece_on(move_to(m))) + -int(pos.type_of_piece_on(move_from(m))); + } + else + { + // Losing capture, move it to the badCaptures[] array + assert(numOfBadCaptures < 63); + moves[i].score = seeValue; + badCaptures[numOfBadCaptures++] = moves[i]; + moves[i--] = moves[--numOfMoves]; + } } } 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. + Move m; + int hs; + + for (int i = 0; i < numOfMoves; i++) + { + m = moves[i].move; + + if (m == killer1) + hs = HistoryMax + 2; + else if (m == killer2) + hs = HistoryMax + 1; + else + hs = H.move_ordering_score(pos.piece_on(move_from(m)), m); + + // Ensure moves in history are always sorted as first + if (hs > 0) + hs += 1000; + + moves[i].score = hs + pos.mg_pst_delta(m); } } 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); + + 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); } + // FIXME try psqt also here } 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; + + // 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.type_of_piece_on(move_from(m))); } } +/// find_best_index() loops across the moves and returns index of +/// the highest scored one. There is also a second version that +/// lowers the priority of moves that attack the same square, +/// so that if the best move that attack a square fails the next +/// move picked attacks a different square if any, not the same one. + +int MovePicker::find_best_index() { + + int bestScore = -10000000, bestIndex = -1; + + for (int i = movesPicked; i < numOfMoves; i++) + if (moves[i].score > bestScore) + { + bestIndex = i; + bestScore = moves[i].score; + } + return bestIndex; +} + +int MovePicker::find_best_index(Bitboard* squares, int values[]) { + + int hs; + Move m; + Square to; + int bestScore = -10000000, bestIndex = -1; + + for (int i = movesPicked; i < numOfMoves; i++) + { + m = moves[i].move; + to = move_to(m); + + if (!bit_is_set(*squares, to)) + { + // Init at first use + set_bit(squares, to); + values[to] = 0; + } + + hs = moves[i].score - values[to]; + if (hs > bestScore) + { + bestIndex = i; + bestScore = hs; + } + } + + if (bestIndex != -1) + { + // Raise value of the picked square, so next attack + // to the same square will get low priority. + to = move_to(moves[bestIndex].move); + values[to] += 0xB00; + } + return bestIndex; +} + + /// 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::pick_move_from_list() { - int bestScore = -10000000; + int bestIndex; Move move; - switch(PhaseTable[phaseIndex]) { - + switch (PhaseTable[phaseIndex]) { 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; + assert(!pos.is_check()); + assert(movesPicked >= 0); + + while (movesPicked < numOfMoves) + { + bestIndex = find_best_index(); + + if (bestIndex != -1) // Found a good capture + { + move = moves[bestIndex].move; + moves[bestIndex] = moves[movesPicked++]; + if ( move != ttMove + && move != mateKiller + && pos.pl_move_is_legal(move, pinned)) + return move; + } } - } - break; + break; 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; + assert(!pos.is_check()); + assert(movesPicked >= 0); + + while (movesPicked < numOfMoves) + { + // 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. + bestIndex = (pvNode || movesPicked < 12) ? find_best_index() : movesPicked; + + if (bestIndex != -1) + { + move = moves[bestIndex].move; + moves[bestIndex] = moves[movesPicked++]; + if ( move != ttMove + && move != mateKiller + && pos.pl_move_is_legal(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; + 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; - } + assert(pos.is_check()); + assert(movesPicked >= 0); + + while (movesPicked < numOfMoves) + { + bestIndex = find_best_index(); + + 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; + 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.pl_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; + assert(!pos.is_check()); + assert(movesPicked >= 0); + while (movesPicked < numOfMoves) + { + bestIndex = (movesPicked < 4 ? find_best_index() : 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.pl_move_is_legal(move, pinned)) + return move; } } - 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_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; + 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.pl_move_is_legal(move, pinned)) + return move; + } + break; default: - break; + break; } - return MOVE_NONE; } + +/// MovePicker::current_move_type() returns the type of the just +/// picked next move. It can be used in search to further differentiate +/// according to the current move type: capture, non capture, escape, etc. MovePicker::MovegenPhase MovePicker::current_move_type() const { + return PhaseTable[phaseIndex]; } + /// 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. +/// QsearchNoCapturesPhaseIndex, QsearchWithoutChecksPhaseIndex and +/// NoMovesPhaseIndex 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 @@ -474,8 +536,17 @@ void MovePicker::init_phase_table() { PhaseTable[i++] = PH_QCHECKS; PhaseTable[i++] = PH_STOP; + // Quiescence search with checks only and no captures + QsearchNoCapturesPhaseIndex = i - 1; + PhaseTable[i++] = PH_QCHECKS; + PhaseTable[i++] = PH_STOP; + // Quiescence search without checks QsearchWithoutChecksPhaseIndex = i - 1; PhaseTable[i++] = PH_QCAPTURES; PhaseTable[i++] = PH_STOP; + + // Do not generate any move + NoMovesPhaseIndex = i - 1; + PhaseTable[i++] = PH_STOP; }