From b96db269a87549ceefaf8b812c050292f81b6c5c Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Sat, 21 Jan 2012 23:32:48 +0100 Subject: [PATCH 1/1] Reshuffle stuff in MovePicker No functional change. Signed-off-by: Marco Costalba --- src/movepick.cpp | 244 ++++++++++++++++++++++------------------------- src/movepick.h | 20 ++-- 2 files changed, 122 insertions(+), 142 deletions(-) diff --git a/src/movepick.cpp b/src/movepick.cpp index 3da4247a..e5aef10d 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -23,8 +23,6 @@ #include "movegen.h" #include "movepick.h" -#include "search.h" -#include "types.h" namespace { @@ -32,17 +30,17 @@ namespace { MAIN_SEARCH, TT_MOVE_S1, GOOD_CAPTURES_S1, KILLERS_S1, NONCAPTURES_1_S1, NONCAPTURES_2_S1, BAD_CAPTURES_S1, STOP_S1, EVASIONS, TT_MOVE_S2, EVASIONS_S2, STOP_S2, - CAPTURES_AND_CHECKS, TT_MOVE_S3, QCAPTURES_S3, QCHECKS_S3, STOP_S3, - CAPTURES, TT_MOVE_S4, QCAPTURES_S4, STOP_S4, - RECAPTURES, TT_MOVE_S5, RECAPTURES_S5, STOP_S5, - PROBCUT, TT_MOVE_S6, GOOD_CAPTURES_S6, STOP_S6 + CAPTURES_AND_CHECKS, TT_MOVE_S3, CAPTURES_S3, CHECKS_S3, STOP_S3, + CAPTURES, TT_MOVE_S4, CAPTURES_S4, STOP_S4, + PROBCUT, TT_MOVE_S5, CAPTURES_S5, STOP_S5, + RECAPTURES, RECAPTURES_S6, STOP_S6 }; // Unary predicate used by std::partition to split positive scores from remaining // ones so to sort separately the two sets, and with the second sort delayed. inline bool has_positive_score(const MoveStack& move) { return move.score > 0; } - // Picks and pushes to the front the best move in range [firstMove, lastMove), + // Picks and moves to the front the best move in the range [firstMove, lastMove), // it is faster than sorting all the moves in advance when moves are few, as // normally are the possible captures. inline MoveStack* pick_best(MoveStack* firstMove, MoveStack* lastMove) @@ -52,7 +50,8 @@ namespace { } } -/// Constructors for the MovePicker class. As arguments we pass information + +/// Constructors of 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 @@ -60,16 +59,16 @@ namespace { MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h, Search::Stack* ss, Value beta) : pos(p), H(h), depth(d) { - captureThreshold = 0; - badCaptures = moves + MAX_MOVES; assert(d > DEPTH_ZERO); + captureThreshold = 0; + curMove = lastMove = 0; + badCaptures = moves + MAX_MOVES; + if (p.in_check()) - { - killers[0].move = killers[1].move = MOVE_NONE; phase = EVASIONS; - } + else { killers[0].move = ss->killers[0]; @@ -87,12 +86,11 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h, } ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE); - phase += int(ttMove == MOVE_NONE); - go_next_phase(); + phase += (ttMove == MOVE_NONE); } -MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h, Square recaptureSq) - : pos(p), H(h) { +MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h, + Square sq) : pos(p), H(h), curMove(0), lastMove(0) { assert(d <= DEPTH_ZERO); @@ -106,26 +104,25 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h, S { phase = CAPTURES; - // 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.is_capture_or_promotion(ttm)) + // 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 && !pos.is_capture_or_promotion(ttm)) ttm = MOVE_NONE; } else { - phase = RECAPTURES; - recaptureSquare = recaptureSq; + phase = RECAPTURES - 1; + recaptureSquare = sq; ttm = MOVE_NONE; } ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE); - phase += int(ttMove == MOVE_NONE); - go_next_phase(); + phase += (ttMove == MOVE_NONE); } MovePicker::MovePicker(const Position& p, Move ttm, const History& h, PieceType parentCapture) - : pos(p), H(h) { + : pos(p), H(h), curMove(0), lastMove(0) { assert (!pos.in_check()); @@ -138,85 +135,7 @@ MovePicker::MovePicker(const Position& p, Move ttm, const History& h, PieceType ttm = MOVE_NONE; ttMove = (ttm && pos.is_pseudo_legal(ttm) ? ttm : MOVE_NONE); - phase += int(ttMove == MOVE_NONE); - go_next_phase(); -} - - -/// 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. - -void MovePicker::go_next_phase() { - - curMove = moves; - - switch (++phase) { - - case TT_MOVE_S1: case TT_MOVE_S2: case TT_MOVE_S3: - case TT_MOVE_S4: case TT_MOVE_S5: case TT_MOVE_S6: - lastMove = curMove + 1; - return; - - case GOOD_CAPTURES_S1: - case GOOD_CAPTURES_S6: - lastMove = generate(pos, moves); - score_captures(); - return; - - case KILLERS_S1: - curMove = killers; - lastMove = curMove + 2; - return; - - case NONCAPTURES_1_S1: - lastNonCapture = lastMove = generate(pos, moves); - score_noncaptures(); - lastMove = std::partition(curMove, lastMove, has_positive_score); - sort(curMove, lastMove); - return; - - case NONCAPTURES_2_S1: - curMove = lastMove; - lastMove = lastNonCapture; - if (depth >= 3 * ONE_PLY) - sort(curMove, lastMove); - return; - - case BAD_CAPTURES_S1: - // Bad captures SEE value is already calculated so just pick - // them in order to get SEE move ordering. - curMove = badCaptures; - lastMove = moves + MAX_MOVES; - return; - - case EVASIONS_S2: - assert(pos.in_check()); - lastMove = generate(pos, moves); - score_evasions(); - return; - - case QCAPTURES_S3: - case QCAPTURES_S4: - lastMove = generate(pos, moves); - score_captures(); - return; - - case RECAPTURES_S5: - lastMove = generate(pos, moves); - return; - - case QCHECKS_S3: - lastMove = generate(pos, moves); - return; - - case STOP_S1: case STOP_S2: case STOP_S3: - case STOP_S4: case STOP_S5: case STOP_S6: - lastMove = curMove + 1; // Avoid another go_next_phase() call - return; - - default: - assert(false); - } + phase += (ttMove == MOVE_NONE); } @@ -241,7 +160,6 @@ void MovePicker::score_captures() { // some SEE calls in case we get a cutoff (idea from Pablo Vazquez). Move m; - // Use MVV/LVA ordering for (MoveStack* cur = moves; cur != lastMove; cur++) { m = cur->move; @@ -267,14 +185,12 @@ void MovePicker::score_noncaptures() { } void MovePicker::score_evasions() { - // 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. + // Try good captures ordered by MVV/LVA, then non-captures if destination square + // is not under attack, ordered by history value, then bad-captures and quiet + // moves 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; @@ -291,6 +207,73 @@ void MovePicker::score_evasions() { } } + +/// MovePicker::next_phase() generates, scores and sorts the next bunch of moves, +/// when there are no more moves to try for the current phase. + +void MovePicker::next_phase() { + + curMove = moves; + + switch (++phase) { + + case TT_MOVE_S1: case TT_MOVE_S2: case TT_MOVE_S3: case TT_MOVE_S4: case TT_MOVE_S5: + lastMove = curMove + 1; + return; + + case GOOD_CAPTURES_S1: + case CAPTURES_S3: case CAPTURES_S4: case CAPTURES_S5: + case RECAPTURES_S6: + lastMove = generate(pos, moves); + score_captures(); + return; + + case KILLERS_S1: + curMove = killers; + lastMove = curMove + 2; + return; + + case NONCAPTURES_1_S1: + lastNonCapture = lastMove = generate(pos, moves); + score_noncaptures(); + lastMove = std::partition(curMove, lastMove, has_positive_score); + sort(curMove, lastMove); + return; + + case NONCAPTURES_2_S1: + curMove = lastMove; + lastMove = lastNonCapture; + if (depth >= 3 * ONE_PLY) + sort(curMove, lastMove); + return; + + case BAD_CAPTURES_S1: + // Bad captures SEE value is already calculated so just pick them in order + // to get SEE move ordering. + curMove = badCaptures; + lastMove = moves + MAX_MOVES; + return; + + case EVASIONS_S2: + assert(pos.in_check()); + lastMove = generate(pos, moves); + score_evasions(); + return; + + case CHECKS_S3: + lastMove = generate(pos, moves); + return; + + case STOP_S1: case STOP_S2: case STOP_S3: case STOP_S4: case STOP_S5: case STOP_S6: + lastMove = curMove + 1; // Avoid another next_phase() call + return; + + default: + assert(false); + } +} + + /// MovePicker::next_move() is the most important method of the MovePicker 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 @@ -305,12 +288,11 @@ Move MovePicker::next_move() { while (true) { while (curMove == lastMove) - go_next_phase(); + next_phase(); switch (phase) { - case TT_MOVE_S1: case TT_MOVE_S2: case TT_MOVE_S3: - case TT_MOVE_S4: case TT_MOVE_S5: case TT_MOVE_S6: + case TT_MOVE_S1: case TT_MOVE_S2: case TT_MOVE_S3: case TT_MOVE_S4: case TT_MOVE_S5: curMove++; return ttMove; break; @@ -319,26 +301,18 @@ Move MovePicker::next_move() { move = pick_best(curMove++, lastMove)->move; if (move != ttMove) { - assert(captureThreshold <= 0); // Otherwise we must use see instead of see_sign + assert(captureThreshold <= 0); // Otherwise we cannot use see_sign() - // Check for a non negative SEE now - int seeValue = pos.see_sign(move); - if (seeValue >= captureThreshold) + int seeScore = pos.see_sign(move); + if (seeScore >= captureThreshold) return move; // Losing capture, move it to the tail of the array (--badCaptures)->move = move; - badCaptures->score = seeValue; + badCaptures->score = seeScore; } break; - case GOOD_CAPTURES_S6: - move = pick_best(curMove++, lastMove)->move; - if ( move != ttMove - && pos.see(move) > captureThreshold) - return move; - break; - case KILLERS_S1: move = (curMove++)->move; if ( move != MOVE_NONE @@ -362,27 +336,33 @@ Move MovePicker::next_move() { return move; case EVASIONS_S2: - case QCAPTURES_S3: - case QCAPTURES_S4: + case CAPTURES_S3: + case CAPTURES_S4: move = pick_best(curMove++, lastMove)->move; if (move != ttMove) return move; break; - case RECAPTURES_S5: + case CAPTURES_S5: + move = pick_best(curMove++, lastMove)->move; + if ( move != ttMove + && pos.see(move) > captureThreshold) + return move; + break; + + case RECAPTURES_S6: move = (curMove++)->move; if (to_sq(move) == recaptureSquare) return move; break; - case QCHECKS_S3: + case CHECKS_S3: move = (curMove++)->move; if (move != ttMove) return move; break; - case STOP_S1: case STOP_S2: case STOP_S3: - case STOP_S4: case STOP_S5: case STOP_S6: + case STOP_S1: case STOP_S2: case STOP_S3: case STOP_S4: case STOP_S5: case STOP_S6: return MOVE_NONE; default: diff --git a/src/movepick.h b/src/movepick.h index 9bc4f469..317a0fc9 100644 --- a/src/movepick.h +++ b/src/movepick.h @@ -25,13 +25,13 @@ #include "search.h" #include "types.h" -/// MovePicker is a class which is used to pick one pseudo legal move at a time -/// from the current position. It is initialized with a Position object and a few -/// moves we have reason to believe are good. The most important method is -/// MovePicker::next_move(), which returns a new pseudo legal move each time -/// it is called, until there are no moves left, when MOVE_NONE is returned. -/// In order to improve the efficiency of the alpha beta algorithm, MovePicker -/// attempts to return the moves which are most likely to get a cut-off first. + +/// MovePicker class is used to pick one pseudo legal move at a time from the +/// current position. The most important method is next_move(), which returns a +/// new pseudo legal move each time it is called, until there are no moves left, +/// when MOVE_NONE is returned. In order to improve the efficiency of the alpha +/// beta algorithm, MovePicker attempts to return the moves which are most likely +/// to get a cut-off first. class MovePicker { @@ -39,15 +39,15 @@ class MovePicker { public: MovePicker(const Position&, Move, Depth, const History&, Search::Stack*, Value); - MovePicker(const Position&, Move, Depth, const History&, Square recaptureSq); - MovePicker(const Position&, Move, const History&, PieceType parentCapture); + MovePicker(const Position&, Move, Depth, const History&, Square); + MovePicker(const Position&, Move, const History&, PieceType); Move next_move(); private: void score_captures(); void score_noncaptures(); void score_evasions(); - void go_next_phase(); + void next_phase(); const Position& pos; const History& H; -- 2.39.2