X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=b35d1012cb817f718f6700d495fd9f08a5276ee1;hp=d8c9fbbb3341622b4407956894e5656ce8460d32;hb=fca0a2dd881e6bde0a01d3342dd385600e01730b;hpb=4dc7ba16191bd1ded7c8257afd2a3b9194cebca8 diff --git a/src/movepick.cpp b/src/movepick.cpp index d8c9fbbb..b35d1012 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -28,11 +28,12 @@ namespace { enum MovegenPhase { - PH_TT_MOVES, // Transposition table move and mate killer - PH_GOOD_CAPTURES, // Queen promotions and captures with SEE values >= 0 + PH_TT_MOVE, // Transposition table move + PH_GOOD_CAPTURES, // Queen promotions and captures with SEE values >= captureThreshold (captureThreshold <= 0) + PH_GOOD_PROBCUT, // Queen promotions and captures with SEE values > captureThreshold (captureThreshold >= 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_BAD_CAPTURES, // Queen promotions and captures with SEE values < captureThreshold (captureThreshold <= 0) PH_EVASIONS, // Check evasions PH_QCAPTURES, // Captures in quiescence search PH_QCHECKS, // Non-capture checks in quiescence search @@ -40,15 +41,14 @@ namespace { }; CACHE_LINE_ALIGNMENT - const uint8_t MainSearchTable[] = { PH_TT_MOVES, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP }; - const uint8_t EvasionTable[] = { PH_TT_MOVES, PH_EVASIONS, PH_STOP }; - const uint8_t QsearchWithChecksTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_QCHECKS, PH_STOP }; - const uint8_t QsearchWithoutChecksTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_STOP }; + const uint8_t MainSearchTable[] = { PH_TT_MOVE, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP }; + const uint8_t EvasionTable[] = { PH_TT_MOVE, PH_EVASIONS, PH_STOP }; + const uint8_t QsearchWithChecksTable[] = { PH_TT_MOVE, PH_QCAPTURES, PH_QCHECKS, PH_STOP }; + const uint8_t QsearchWithoutChecksTable[] = { PH_TT_MOVE, PH_QCAPTURES, PH_STOP }; + const uint8_t ProbCutTable[] = { PH_TT_MOVE, PH_GOOD_PROBCUT, PH_STOP }; } - -/// Constructor for the MovePicker class. Apart from the position for which -/// it is asked to pick legal moves, MovePicker also wants some information +/// Constructors for the MovePicker class. As arguments we pass 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 /// search captures, promotions and some checks) and about how important good @@ -56,49 +56,39 @@ namespace { MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value beta) : pos(p), H(h) { - int searchTT = ttm; - ttMoves[0].move = ttm; - badCaptureThreshold = 0; + captureThreshold = 0; badCaptures = moves + MAX_MOVES; assert(d > DEPTH_ZERO); - pinned = p.pinned_pieces(pos.side_to_move()); - if (p.in_check()) { - ttMoves[1].move = killers[0].move = killers[1].move = MOVE_NONE; + killers[0].move = killers[1].move = MOVE_NONE; phasePtr = EvasionTable; } else { - 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]; // Consider sligtly negative captures as good if at low // depth and far from beta. if (ss && ss->eval < beta - PawnValueMidgame && d < 3 * ONE_PLY) - badCaptureThreshold = -PawnValueMidgame; + captureThreshold = -PawnValueMidgame; phasePtr = MainSearchTable; } - phasePtr += int(!searchTT) - 1; + ttMove = (ttm && pos.move_is_pl(ttm) ? ttm : MOVE_NONE); + phasePtr += int(ttMove == MOVE_NONE) - 1; go_next_phase(); } MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h) : pos(p), H(h) { - int searchTT = ttm; - ttMoves[0].move = ttm; - ttMoves[1].move = MOVE_NONE; assert(d <= DEPTH_ZERO); - pinned = p.pinned_pieces(pos.side_to_move()); - if (p.in_check()) phasePtr = EvasionTable; else if (d >= DEPTH_QS_CHECKS) @@ -110,11 +100,30 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h) // 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; + if (ttm != MOVE_NONE && !pos.move_is_capture(ttm) && !move_is_promotion(ttm)) + ttm = MOVE_NONE; } - phasePtr += int(!searchTT) - 1; + ttMove = (ttm && pos.move_is_pl(ttm) ? ttm : MOVE_NONE); + phasePtr += int(ttMove == MOVE_NONE) - 1; + go_next_phase(); +} + +MovePicker::MovePicker(const Position& p, Move ttm, const History& h, int parentCapture) + : pos(p), H(h) { + + assert (!pos.in_check()); + + // In ProbCut we consider only captures better than parent's move + captureThreshold = parentCapture; + phasePtr = ProbCutTable; + + if ( ttm != MOVE_NONE + && (!pos.move_is_capture(ttm) || pos.see(ttm) <= captureThreshold)) + ttm = MOVE_NONE; + + ttMove = (ttm && pos.move_is_pl(ttm) ? ttm : MOVE_NONE); + phasePtr += int(ttMove == MOVE_NONE) - 1; go_next_phase(); } @@ -128,12 +137,12 @@ void MovePicker::go_next_phase() { phase = *(++phasePtr); switch (phase) { - case PH_TT_MOVES: - curMove = ttMoves; - lastMove = curMove + 2; + case PH_TT_MOVE: + lastMove = curMove + 1; return; case PH_GOOD_CAPTURES: + case PH_GOOD_PROBCUT: lastMove = generate(pos, moves); score_captures(); return; @@ -254,7 +263,7 @@ void MovePicker::score_evasions() { } /// 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 +/// class. It returns a new pseudo 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 @@ -271,37 +280,41 @@ Move MovePicker::get_next_move() { switch (phase) { - case PH_TT_MOVES: - move = (curMove++)->move; - if ( move != MOVE_NONE - && pos.move_is_legal(move, pinned)) - return move; + case PH_TT_MOVE: + curMove++; + return ttMove; 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)) + if (move != ttMove) { + assert(captureThreshold <= 0); // Otherwise we must use see instead of see_sign + // Check for a non negative SEE now int seeValue = pos.see_sign(move); - if (seeValue >= badCaptureThreshold) + if (seeValue >= captureThreshold) return move; // Losing capture, move it to the tail of the array, note - // that move has now been already checked for legality. + // that move has now been already checked for pseudo legality. (--badCaptures)->move = move; badCaptures->score = seeValue; } break; + case PH_GOOD_PROBCUT: + move = pick_best(curMove++, lastMove).move; + if ( move != ttMove + && pos.see(move) > captureThreshold) + return move; + break; + case PH_KILLERS: move = (curMove++)->move; if ( move != MOVE_NONE - && pos.move_is_legal(move, pinned) - && move != ttMoves[0].move - && move != ttMoves[1].move + && pos.move_is_pl(move) + && move != ttMove && !pos.move_is_capture(move)) return move; break; @@ -312,11 +325,9 @@ Move MovePicker::get_next_move() { insertion_sort(lastGoodNonCapture, lastMove); move = (curMove++)->move; - if ( move != ttMoves[0].move - && move != ttMoves[1].move + if ( move != ttMove && move != killers[0].move - && move != killers[1].move - && pos.pl_move_is_legal(move, pinned)) + && move != killers[1].move) return move; break; @@ -327,15 +338,13 @@ Move MovePicker::get_next_move() { case PH_EVASIONS: case PH_QCAPTURES: move = pick_best(curMove++, lastMove).move; - if ( move != ttMoves[0].move - && pos.pl_move_is_legal(move, pinned)) + if (move != ttMove) return move; break; case PH_QCHECKS: move = (curMove++)->move; - if ( move != ttMoves[0].move - && pos.pl_move_is_legal(move, pinned)) + if (move != ttMove) return move; break;