X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=901aa60e5625c766b797fd88d4dec2888b24ac69;hp=0b887c99d0afb31abc3c963e7645a4224d082d3a;hb=337ec0f3d0b402782c3704cc251c209393047dd9;hpb=595a90dfd0cd393a8805f4f51cf5c5d8b264c121 diff --git a/src/movepick.cpp b/src/movepick.cpp index 0b887c99..901aa60e 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -23,11 +23,9 @@ //// Includes //// -#include #include #include "history.h" -#include "evaluate.h" #include "movegen.h" #include "movepick.h" #include "search.h" @@ -40,13 +38,23 @@ namespace { - /// Variables + enum MovegenPhase { + PH_TT_MOVES, // Transposition table move and mate killer + PH_GOOD_CAPTURES, // Queen promotions and captures with SEE values >= 0 + PH_KILLERS, // Killer moves from the current ply + PH_NONCAPTURES, // Non-captures and underpromotions + PH_BAD_CAPTURES, // Queen promotions and captures with SEE values < 0 + PH_EVASIONS, // Check evasions + PH_QCAPTURES, // Captures in quiescence search + PH_QCHECKS, // Non-capture checks in quiescence search + PH_STOP + }; CACHE_LINE_ALIGNMENT - const MovegenPhaseT MainSearchPhaseTable[] = { PH_STOP, PH_TT_MOVES, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP}; - const MovegenPhaseT EvasionsPhaseTable[] = { PH_STOP, PH_EVASIONS, PH_STOP}; - const MovegenPhaseT QsearchWithChecksPhaseTable[] = { PH_STOP, PH_TT_MOVES, PH_QCAPTURES, PH_QCHECKS, PH_STOP}; - const MovegenPhaseT QsearchWithoutChecksPhaseTable[] = { PH_STOP, PH_TT_MOVES, PH_QCAPTURES, PH_STOP}; + 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}; } @@ -55,7 +63,7 @@ namespace { //// -/// Constructor for the MovePicker class. Apart from the position for which +/// Constructor for the MovePicker class. Apart from the position for which /// it is asked to pick legal moves, MovePicker also wants some information /// to help it to return the presumably good moves first, to decide which /// moves to return (in the quiescence search, for instance, we only want to @@ -64,17 +72,20 @@ namespace { MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss) : pos(p), H(h) { - ttMoves[0] = ttm; - if (ss) + int searchTT = ttm; + ttMoves[0].move = ttm; + lastBadCapture = badCaptures; + + pinned = p.pinned_pieces(pos.side_to_move()); + + if (ss && !p.is_check()) { - ttMoves[1] = (ss->mateKiller == ttm)? MOVE_NONE : ss->mateKiller; - killers[0] = ss->killers[0]; - killers[1] = ss->killers[1]; + 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]; } else - ttMoves[1] = killers[0] = killers[1] = MOVE_NONE; - - movesPicked = numOfMoves = numOfBadCaptures = 0; - finished = false; + ttMoves[1].move = killers[0].move = killers[1].move = MOVE_NONE; if (p.is_check()) phasePtr = EvasionsPhaseTable; @@ -83,123 +94,89 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, else if (d == Depth(0)) phasePtr = QsearchWithChecksPhaseTable; else + { phasePtr = QsearchWithoutChecksPhaseTable; - Color us = pos.side_to_move(); + // 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; + } - dc = p.discovered_check_candidates(us); - pinned = p.pinned_pieces(us); + phasePtr += !searchTT - 1; + go_next_phase(); } -/// 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. +/// 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. -Move MovePicker::get_next_move() { +void MovePicker::go_next_phase() { - Move move; + curMove = moves; + phase = *(++phasePtr); + switch (phase) { - while (true) - { - // If we already have a list of generated moves, pick the best move from - // the list, and return it. - move = pick_move_from_list(); - if (move != MOVE_NONE) - { - assert(move_is_ok(move)); - return move; - } - - // Next phase - phasePtr++; - switch (*phasePtr) { - - case PH_TT_MOVES: - movesPicked = 0; // This is used as index to ttMoves[] - break; - - case PH_GOOD_CAPTURES: - numOfMoves = generate_captures(pos, moves); - score_captures(); - std::sort(moves, moves + numOfMoves); - movesPicked = 0; - break; - - case PH_KILLERS: - movesPicked = 0; // This is used as index to killers[] - break; - - case PH_NONCAPTURES: - numOfMoves = generate_noncaptures(pos, moves); - score_noncaptures(); - std::sort(moves, moves + numOfMoves); - movesPicked = 0; - break; - - case PH_BAD_CAPTURES: - // Bad captures SEE value is already calculated so just sort them - // to get SEE move ordering. - std::sort(badCaptures, badCaptures + numOfBadCaptures); - movesPicked = 0; - break; - - case PH_EVASIONS: - assert(pos.is_check()); - numOfMoves = generate_evasions(pos, moves, pinned); - score_evasions(); - std::sort(moves, moves + numOfMoves); - movesPicked = 0; - break; - - case PH_QCAPTURES: - numOfMoves = generate_captures(pos, moves); - score_captures(); - std::sort(moves, moves + numOfMoves); - movesPicked = 0; - break; - - case PH_QCHECKS: - // Perhaps we should order moves move here? FIXME - numOfMoves = generate_non_capture_checks(pos, moves, dc); - movesPicked = 0; - break; - - case PH_STOP: - return MOVE_NONE; - - default: - assert(false); - return MOVE_NONE; - } - } -} + case PH_TT_MOVES: + curMove = ttMoves; + lastMove = curMove + 2; + return; + + case PH_GOOD_CAPTURES: + lastMove = generate_captures(pos, moves); + score_captures(); + return; + + case PH_KILLERS: + curMove = killers; + lastMove = curMove + 2; + return; + case PH_NONCAPTURES: + lastMove = generate_noncaptures(pos, moves); + score_noncaptures(); + sort_moves(moves, 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_BAD_CAPTURES: + // Bad captures SEE value is already calculated so just sort them + // to get SEE move ordering. + curMove = badCaptures; + lastMove = lastBadCapture; + return; -Move MovePicker::get_next_move(Lock &lock) { + case PH_EVASIONS: + assert(pos.is_check()); + lastMove = generate_evasions(pos, moves); + score_evasions_or_checks(); + return; - lock_grab(&lock); - if (finished) - { - lock_release(&lock); - return MOVE_NONE; - } - Move m = get_next_move(); - if (m == MOVE_NONE) - finished = true; + case PH_QCAPTURES: + lastMove = generate_captures(pos, moves); + score_captures(); + return; - lock_release(&lock); - return m; + case PH_QCHECKS: + lastMove = generate_non_capture_checks(pos, moves); + score_evasions_or_checks(); + return; + + case PH_STOP: + lastMove = curMove + 1; // Avoids another go_next_phase() call + return; + + 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 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. @@ -218,14 +195,14 @@ void MovePicker::score_captures() { Move m; // Use MVV/LVA ordering - for (int i = 0; i < numOfMoves; i++) + for (MoveStack* cur = moves; cur != lastMove; cur++) { - m = moves[i].move; + m = cur->move; if (move_is_promotion(m)) - moves[i].score = QueenValueMidgame; + cur->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))); + cur->score = pos.midgame_value_of_piece_on(move_to(m)) + - pos.type_of_piece_on(move_from(m)); } } @@ -233,136 +210,138 @@ 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; Piece piece; Square from, to; - int hs; - for (int i = 0; i < numOfMoves; i++) + for (MoveStack* cur = moves; cur != lastMove; cur++) { - from = move_from(moves[i].move); - to = move_to(moves[i].move); + m = cur->move; + 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 - moves[i].score = hs + pos.pst_delta(piece, from, to); + cur->score = H.move_ordering_score(piece, to); } } -void MovePicker::score_evasions() { +void MovePicker::score_evasions_or_checks() { + // Try good captures ordered by MVV/LVA, then non-captures if + // destination square is not under attack, ordered by history + // value, and at the end bad-captures and non-captures with a + // negative SEE. This last group is ordered by the SEE score. + Move m; + int seeScore; + + // Skip if we don't have at least two moves to order + if (lastMove < moves + 2) + return; - for (int i = 0; i < numOfMoves; i++) + for (MoveStack* cur = moves; cur != lastMove; cur++) { - Move m = moves[i].move; - if (m == ttMoves[0]) - 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)), move_to(m)); + m = cur->move; + if ((seeScore = pos.see_sign(m)) < 0) + cur->score = seeScore; + 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)); } } +/// 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 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. -/// 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. - -Move MovePicker::pick_move_from_list() { - - assert(movesPicked >= 0); - assert(!pos.is_check() || *phasePtr == PH_EVASIONS || *phasePtr == PH_STOP); - assert( pos.is_check() || *phasePtr != PH_EVASIONS); - - switch (*phasePtr) { +Move MovePicker::get_next_move() { - case PH_TT_MOVES: - while (movesPicked < 2) { - Move move = ttMoves[movesPicked++]; - if ( move != MOVE_NONE - && move_is_legal(pos, move, pinned)) - return move; - } - break; + Move move; - case PH_GOOD_CAPTURES: - while (movesPicked < numOfMoves) + while (true) + { + while (curMove != lastMove) { - Move move = moves[movesPicked++].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; - } - } - break; + switch (phase) { - 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_TT_MOVES: + move = (curMove++)->move; + if ( move != MOVE_NONE + && move_is_legal(pos, move, pinned)) + return move; + break; + + case PH_GOOD_CAPTURES: + move = pick_best(curMove++, lastMove).move; + if ( move != ttMoves[0].move + && move != ttMoves[1].move + && 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(int(lastBadCapture - badCaptures) < 63); + lastBadCapture->move = move; + lastBadCapture->score = seeValue; + lastBadCapture++; + } + break; + + case PH_KILLERS: + move = (curMove++)->move; + if ( move != MOVE_NONE + && 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: + move = (curMove++)->move; + if ( move != ttMoves[0].move + && move != ttMoves[1].move + && move != killers[0].move + && move != killers[1].move + && pos.pl_move_is_legal(move, pinned)) + return move; + break; - case PH_NONCAPTURES: - while (movesPicked < numOfMoves) - { - Move move = moves[movesPicked++].move; - if ( move != ttMoves[0] - && move != ttMoves[1] - && move != killers[0] - && move != killers[1] - && pos.pl_move_is_legal(move, pinned)) + case PH_BAD_CAPTURES: + move = pick_best(curMove++, lastMove).move; return move; - } - break; - case PH_EVASIONS: - if (movesPicked < numOfMoves) - return moves[movesPicked++].move; - break; + case PH_EVASIONS: + case PH_QCAPTURES: + move = pick_best(curMove++, lastMove).move; + if ( move != ttMoves[0].move + && pos.pl_move_is_legal(move, pinned)) + return move; + break; - case PH_BAD_CAPTURES: - if (movesPicked < numOfBadCaptures) - return badCaptures[movesPicked++].move; - break; + case PH_QCHECKS: + move = (curMove++)->move; + if ( move != ttMoves[0].move + && pos.pl_move_is_legal(move, pinned)) + return move; + break; - case PH_QCAPTURES: - case PH_QCHECKS: - while (movesPicked < numOfMoves) - { - Move move = moves[movesPicked++].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_STOP: + return MOVE_NONE; - default: - break; + default: + assert(false); + break; + } + } + go_next_phase(); } - return MOVE_NONE; } +