X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=c71572e7cf86bead8aa853dd16db512ab329e55d;hp=1024cbffede226903eaf47f8f48e2001cabfe370;hb=d087b0a34a6aaa0fc31d2fa256b02861d0351256;hpb=94f1b31484c2415b19a43f385e92cd1cb4bd7ecc diff --git a/src/movepick.cpp b/src/movepick.cpp index 1024cbff..c71572e7 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 . */ @@ -38,7 +40,7 @@ namespace { /// Variables - MovePicker::MovegenPhase PhaseTable[32]; + MovePicker::MovegenPhase PhaseTable[32]; int MainSearchPhaseIndex; int EvasionsPhaseIndex; int QsearchWithChecksPhaseIndex; @@ -61,7 +63,7 @@ namespace { /// 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) { + Move k1, Move k2, Depth d) : pos(p) { pvNode = pvnode; ttMove = ttm; mateKiller = (mk == ttm)? MOVE_NONE : mk; @@ -115,7 +117,7 @@ Move MovePicker::get_next_move() { if (ttMove != MOVE_NONE) { assert(move_is_ok(ttMove)); - if (generate_move_if_legal(pos, ttMove, pinned) != MOVE_NONE) + if (move_is_legal(pos, ttMove, pinned)) return ttMove; } break; @@ -124,12 +126,12 @@ Move MovePicker::get_next_move() { if (mateKiller != MOVE_NONE) { assert(move_is_ok(mateKiller)); - if (generate_move_if_legal(pos, mateKiller, pinned) != MOVE_NONE) + if (move_is_legal(pos, mateKiller, pinned)) return mateKiller; - } - break; + } + break; - case PH_GOOD_CAPTURES: + case PH_GOOD_CAPTURES: numOfMoves = generate_captures(pos, moves); score_captures(); movesPicked = 0; @@ -146,13 +148,13 @@ Move MovePicker::get_next_move() { break; case PH_EVASIONS: - assert(pos.is_check()); + assert(pos.is_check()); numOfMoves = generate_evasions(pos, moves); score_evasions(); movesPicked = 0; break; - case PH_QCAPTURES: + case PH_QCAPTURES: numOfMoves = generate_captures(pos, moves); score_qcaptures(); movesPicked = 0; @@ -171,9 +173,6 @@ Move MovePicker::get_next_move() { return MOVE_NONE; } } - assert(false); - - return MOVE_NONE; } @@ -182,62 +181,73 @@ Move MovePicker::get_next_move() { 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; + 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; } + /// 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 pick_move_from_list(). void MovePicker::score_captures() { - // Winning and equal captures in the main search are ordered by MVV. + // 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 // 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. + // the subtree size. Instead of calculating SEE here to filter out + // loosing captures, we delay the filtering in pick_move_from_list() + Move m; + for (int i = 0; i < numOfMoves; i++) { - Move m = moves[i].move; - moves[i].score = pos.see(m); - if (moves[i].score >= 0) - moves[i].score = move_promotion(m) ? QueenValueMidgame - : pos.midgame_value_of_piece_on(move_to(m)); + 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))); } } void MovePicker::score_noncaptures() { + // 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++) { - Move m = moves[i].move; + m = moves[i].move; + if (m == killer1) - moves[i].score = HistoryMax + 2; + hs = HistoryMax + 2; else if (m == killer2) - moves[i].score = HistoryMax + 1; + hs = HistoryMax + 1; else - moves[i].score = H.move_ordering_score(pos.piece_on(move_from(m)), m); + hs = H.move_ordering_score(pos.piece_on(move_from(m)), m); // Ensure moves in history are always sorted as first - if (moves[i].score > 0) - moves[i].score += 1000; + if (hs > 0) + hs += 1000; - moves[i].score += pos.mg_pst_delta(moves[i].move); + moves[i].score = hs + pos.mg_pst_delta(m); } } @@ -250,11 +260,9 @@ void MovePicker::score_evasions() { moves[i].score = 2*HistoryMax; else if (!pos.square_is_empty(move_to(m))) { - moves[i].score = pos.see(m); - if (moves[i].score >= 0) - moves[i].score += HistoryMax; - } - else + 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 @@ -262,12 +270,15 @@ void MovePicker::score_evasions() { void MovePicker::score_qcaptures() { - // Use MVV ordering + // Use MVV/LVA ordering for (int i = 0; i < numOfMoves; i++) { Move m = moves[i].move; - moves[i].score = move_promotion(m) ? QueenValueMidgame - : pos.midgame_value_of_piece_on(move_to(m)); + 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))); } } @@ -303,36 +314,31 @@ Move MovePicker::pick_move_from_list() { Move move; switch (PhaseTable[phaseIndex]) { - case PH_GOOD_CAPTURES: assert(!pos.is_check()); assert(movesPicked >= 0); + while (movesPicked < numOfMoves) { - int bestScore = -10000000; - bestIndex = -1; - for (int i = movesPicked; i < numOfMoves; i++) + bestIndex = find_best_index(); + + if (bestIndex != -1) // Found a possibly good capture { - if (moves[i].score < 0) + move = moves[bestIndex].move; + int seeValue = pos.see(move); + if (seeValue < 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].score = seeValue; + badCaptures[numOfBadCaptures++] = moves[bestIndex]; + moves[bestIndex] = moves[--numOfMoves]; + continue; + } moves[bestIndex] = moves[movesPicked++]; if ( move != ttMove && move != mateKiller - && pos.move_is_legal(move, pinned)) + && pos.pl_move_is_legal(move, pinned)) return move; } } @@ -341,41 +347,43 @@ Move MovePicker::pick_move_from_list() { case PH_NONCAPTURES: 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 = (movesPicked < 12 || pvNode ? find_best_index() : movesPicked); + bestIndex = (pvNode || movesPicked < 12) ? find_best_index() : movesPicked; if (bestIndex != -1) { - move = moves[bestIndex].move; + move = moves[bestIndex].move; moves[bestIndex] = moves[movesPicked++]; if ( move != ttMove && move != mateKiller - && pos.move_is_legal(move, pinned)) + && pos.pl_move_is_legal(move, pinned)) return move; - } - } - break; + } + } + break; case PH_EVASIONS: assert(pos.is_check()); assert(movesPicked >= 0); + while (movesPicked < numOfMoves) { bestIndex = find_best_index(); if (bestIndex != -1) { - move = moves[bestIndex].move; + move = moves[bestIndex].move; moves[bestIndex] = moves[movesPicked++]; return move; } - } - break; + } + break; case PH_BAD_CAPTURES: assert(!pos.is_check()); @@ -387,7 +395,7 @@ Move MovePicker::pick_move_from_list() { move = badCaptures[badCapturesPicked++].move; if ( move != ttMove && move != mateKiller - && pos.move_is_legal(move, pinned)) + && pos.pl_move_is_legal(move, pinned)) return move; } break; @@ -397,14 +405,15 @@ Move MovePicker::pick_move_from_list() { assert(movesPicked >= 0); while (movesPicked < numOfMoves) { - // FIXME makes sens to score qcaps? bestIndex = (movesPicked < 4 ? find_best_index() : movesPicked); if (bestIndex != -1) { - move = moves[bestIndex].move; + move = moves[bestIndex].move; moves[bestIndex] = moves[movesPicked++]; - if (move != ttMove && pos.move_is_legal(move, pinned)) + // 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; } } @@ -417,8 +426,9 @@ Move MovePicker::pick_move_from_list() { // move here? FIXME while (movesPicked < numOfMoves) { - move = moves[movesPicked++].move; - if (move != ttMove && pos.move_is_legal(move, pinned)) + 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; @@ -441,7 +451,7 @@ 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 +/// and QsearchWithoutChecksPhaseIndex variables. It is only called once /// during program startup, and never again while the program is running. void MovePicker::init_phase_table() {