X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=671430708575ab1c6e2834ba9ce2e7c0594b0aa2;hp=59855dba66a56d0ab808f3f75bfce778aca4ee23;hb=67535711e8d86a975ff9aac9c2d2fdad24ec5915;hpb=3e275680d5e9a2b335cddd4bd96bed494987933d diff --git a/src/movepick.cpp b/src/movepick.cpp index 59855dba..67143070 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -26,6 +26,7 @@ #include #include "history.h" +#include "evaluate.h" #include "movegen.h" #include "movepick.h" #include "search.h" @@ -44,7 +45,9 @@ namespace { int MainSearchPhaseIndex; int EvasionsPhaseIndex; int QsearchWithChecksPhaseIndex; + int QsearchNoCapturesPhaseIndex; int QsearchWithoutChecksPhaseIndex; + int NoMovesPhaseIndex; } @@ -62,28 +65,38 @@ namespace { /// search captures, promotions and some checks) and about how important good /// move ordering is at the current node. -MovePicker::MovePicker(const Position& p, bool pvnode, Move ttm, Move mk, - Move k1, Move k2, Depth d) : 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; + mateKiller = (ss.mateKiller == ttm)? MOVE_NONE : ss.mateKiller; + killer1 = ss.killers[0]; + killer2 = ss.killers[1]; depth = d; movesPicked = 0; numOfMoves = 0; numOfBadCaptures = 0; - dc = p.discovered_check_candidates(p.side_to_move()); + + // 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; + phaseIndex = EvasionsPhaseIndex; else if (depth > Depth(0)) - phaseIndex = MainSearchPhaseIndex; + phaseIndex = MainSearchPhaseIndex; else if (depth == Depth(0)) - phaseIndex = QsearchWithChecksPhaseIndex; + 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; @@ -138,7 +151,7 @@ Move MovePicker::get_next_move() { break; case PH_BAD_CAPTURES: - badCapturesPicked = 0; + movesPicked = 0; break; case PH_NONCAPTURES: @@ -149,7 +162,7 @@ Move MovePicker::get_next_move() { case PH_EVASIONS: assert(pos.is_check()); - numOfMoves = generate_evasions(pos, moves); + numOfMoves = generate_evasions(pos, moves, pinned); score_evasions(); movesPicked = 0; break; @@ -206,22 +219,36 @@ void MovePicker::score_captures() { // Suprisingly, this appears to perform slightly better than SEE based // 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 // big pieces before capturing a hanging piece probably helps to reduce - // the subtree size. Instead of calculating SEE here to filter out - // loosing captures, we delay the filtering in pick_move_from_list() + // the subtree size. + // 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; - if (move_promotion(m)) - moves[i].score = QueenValueMidgame; + 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 - moves[i].score = int(pos.midgame_value_of_piece_on(move_to(m))) - -int(pos.type_of_piece_on(move_from(m))); + { + // Losing capture, move it to the badCaptures[] array + assert(numOfBadCaptures < 63); + moves[i].score = seeValue; + badCaptures[numOfBadCaptures++] = moves[i]; + moves[i--] = moves[--numOfMoves]; + } } } @@ -243,34 +270,29 @@ void MovePicker::score_noncaptures() { else hs = H.move_ordering_score(pos.piece_on(move_from(m)), m); - // Ensure moves in history are always sorted as first + // Ensure history is always preferred to pst if (hs > 0) hs += 1000; + // pst based scoring moves[i].score = hs + pos.mg_pst_delta(m); } } -void MovePicker::score_evasions() { - - Move m; - int hs; - - // Use MVV/LVA ordering - for (int i = 0; i < numOfMoves; i++) - { - m = moves[i].move; - - if (m == ttMove) - hs = 2*HistoryMax; - else if (!pos.square_is_empty(move_to(m))) - hs = int(pos.midgame_value_of_piece_on(move_to(m))) - -int(pos.type_of_piece_on(move_from(m))) + HistoryMax; - else - hs = H.move_ordering_score(pos.piece_on(move_from(m)), m); - - moves[i].score = hs; - } +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() { @@ -289,13 +311,18 @@ void MovePicker::score_qcaptures() { /// find_best_index() loops across the moves and returns index of -/// the highest scored one. +/// 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; + assert(movesPicked < numOfMoves); - for (int i = movesPicked; i < numOfMoves; i++) + int bestIndex = movesPicked, bestScore = moves[movesPicked].score; + + for (int i = movesPicked + 1; i < numOfMoves; i++) if (moves[i].score > bestScore) { bestIndex = i; @@ -304,14 +331,50 @@ int MovePicker::find_best_index() { return bestIndex; } +int MovePicker::find_best_index(Bitboard* squares, int values[]) { + + assert(movesPicked < numOfMoves); + + 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() { @@ -319,6 +382,7 @@ Move MovePicker::pick_move_from_list() { Move move; switch (PhaseTable[phaseIndex]) { + case PH_GOOD_CAPTURES: assert(!pos.is_check()); assert(movesPicked >= 0); @@ -326,26 +390,12 @@ Move MovePicker::pick_move_from_list() { while (movesPicked < numOfMoves) { bestIndex = find_best_index(); - - if (bestIndex != -1) // Found a possibly good capture - { - move = moves[bestIndex].move; - int seeValue = pos.see(move); - if (seeValue < 0) - { - // Losing capture, move it to the badCaptures[] array - assert(numOfBadCaptures < 63); - moves[bestIndex].score = seeValue; - badCaptures[numOfBadCaptures++] = moves[bestIndex]; - moves[bestIndex] = moves[--numOfMoves]; - continue; - } - moves[bestIndex] = moves[movesPicked++]; - if ( move != ttMove - && move != mateKiller - && pos.pl_move_is_legal(move, pinned)) - return move; - } + move = moves[bestIndex].move; + moves[bestIndex] = moves[movesPicked++]; + if ( move != ttMove + && move != mateKiller + && pos.pl_move_is_legal(move, pinned)) + return move; } break; @@ -360,16 +410,12 @@ Move MovePicker::pick_move_from_list() { // 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; - } + move = moves[bestIndex].move; + moves[bestIndex] = moves[movesPicked++]; + if ( move != ttMove + && move != mateKiller + && pos.pl_move_is_legal(move, pinned)) + return move; } break; @@ -380,24 +426,20 @@ Move MovePicker::pick_move_from_list() { while (movesPicked < numOfMoves) { bestIndex = find_best_index(); - - if (bestIndex != -1) - { - move = moves[bestIndex].move; - moves[bestIndex] = moves[movesPicked++]; - return move; - } + move = moves[bestIndex].move; + moves[bestIndex] = moves[movesPicked++]; + return move; } break; case PH_BAD_CAPTURES: assert(!pos.is_check()); - assert(badCapturesPicked >= 0); + assert(movesPicked >= 0); // It's probably a good idea to use SEE move ordering here, instead // of just picking the first move. FIXME - while (badCapturesPicked < numOfBadCaptures) + while (movesPicked < numOfBadCaptures) { - move = badCaptures[badCapturesPicked++].move; + move = badCaptures[movesPicked++].move; if ( move != ttMove && move != mateKiller && pos.pl_move_is_legal(move, pinned)) @@ -411,16 +453,12 @@ Move MovePicker::pick_move_from_list() { 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; - } + 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; } break; @@ -456,8 +494,9 @@ MovePicker::MovegenPhase MovePicker::current_move_type() const { /// 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() { @@ -486,8 +525,17 @@ 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; }