along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <algorithm>
#include <cassert>
#include "movegen.h"
PH_BAD_CAPTURES, // Queen promotions and captures with SEE values < captureThreshold (captureThreshold <= 0)
PH_EVASIONS, // Check evasions
PH_QCAPTURES, // Captures in quiescence search
+ PH_QRECAPTURES, // Recaptures in quiescence search
PH_QCHECKS, // Non-capture checks in quiescence search
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 QsearchRecapturesTable[] = { PH_TT_MOVE, PH_QRECAPTURES, PH_STOP };
const uint8_t ProbCutTable[] = { PH_TT_MOVE, PH_GOOD_PROBCUT, PH_STOP };
+
+ // 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),
+ // 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)
+ {
+ std::swap(*firstMove, *std::max_element(firstMove, lastMove));
+ return firstMove;
+ }
}
/// Constructors for the MovePicker class. As arguments we pass information
go_next_phase();
}
-MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h)
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h, Square recaptureSq)
: pos(p), H(h) {
assert(d <= DEPTH_ZERO);
phasePtr = EvasionTable;
else if (d >= DEPTH_QS_CHECKS)
phasePtr = QsearchWithChecksTable;
- else
+ else if (d >= DEPTH_QS_RECAPTURES)
{
phasePtr = QsearchWithoutChecksTable;
// 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(ttm) && !move_is_promotion(ttm))
+ if (ttm != MOVE_NONE && !pos.move_is_capture_or_promotion(ttm))
ttm = MOVE_NONE;
}
+ else
+ {
+ phasePtr = QsearchRecapturesTable;
+ recaptureSquare = recaptureSq;
+ ttm = MOVE_NONE;
+ }
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)
+MovePicker::MovePicker(const Position& p, Move ttm, const History& h, PieceType parentCapture)
: pos(p), H(h) {
assert (!pos.in_check());
// In ProbCut we consider only captures better than parent's move
- captureThreshold = parentCapture;
+ captureThreshold = piece_value_midgame(Piece(parentCapture));
phasePtr = ProbCutTable;
if ( ttm != MOVE_NONE
case PH_NONCAPTURES_1:
lastNonCapture = lastMove = generate<MV_NON_CAPTURE>(pos, moves);
score_noncaptures();
- sort_moves(moves, lastNonCapture, &lastMove);
+ lastMove = std::partition(curMove, lastMove, has_positive_score);
+ sort<MoveStack>(curMove, lastMove);
return;
case PH_NONCAPTURES_2:
curMove = lastMove;
lastMove = lastNonCapture;
if (depth >= 3 * ONE_PLY)
- insertion_sort<MoveStack>(curMove, lastMove);
+ sort<MoveStack>(curMove, lastMove);
return;
case PH_BAD_CAPTURES:
score_captures();
return;
+ case PH_QRECAPTURES:
+ lastMove = generate<MV_CAPTURE>(pos, moves);
+ return;
+
case PH_QCHECKS:
lastMove = generate<MV_NON_CAPTURE_CHECK>(pos, moves);
return;
for (MoveStack* cur = moves; cur != lastMove; cur++)
{
m = cur->move;
+ cur->score = piece_value_midgame(pos.piece_on(move_to(m)))
+ - piece_type(pos.piece_on(move_from(m)));
+
if (move_is_promotion(m))
- cur->score = QueenValueMidgame;
- else
- cur->score = pos.midgame_value_of_piece_on(move_to(m))
- - pos.type_of_piece_on(move_from(m));
+ cur->score += piece_value_midgame(Piece(promotion_piece_type(m)));
}
}
if ((seeScore = pos.see_sign(m)) < 0)
cur->score = seeScore - History::MaxValue; // Be sure we are at the bottom
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)) + History::MaxValue;
+ cur->score = piece_value_midgame(pos.piece_on(move_to(m)))
+ - piece_type(pos.piece_on(move_from(m))) + History::MaxValue;
else
cur->score = H.value(pos.piece_on(move_from(m)), move_to(m));
}
break;
case PH_GOOD_CAPTURES:
- move = pick_best(curMove++, lastMove).move;
+ move = pick_best(curMove++, lastMove)->move;
if (move != ttMove)
{
assert(captureThreshold <= 0); // Otherwise we must use see instead of see_sign
if (seeValue >= captureThreshold)
return move;
- // Losing capture, move it to the tail of the array, note
- // that move has now been already checked for pseudo legality.
+ // Losing capture, move it to the tail of the array
(--badCaptures)->move = move;
badCaptures->score = seeValue;
}
break;
case PH_GOOD_PROBCUT:
- move = pick_best(curMove++, lastMove).move;
+ move = pick_best(curMove++, lastMove)->move;
if ( move != ttMove
&& pos.see(move) > captureThreshold)
return move;
break;
case PH_BAD_CAPTURES:
- move = pick_best(curMove++, lastMove).move;
+ move = pick_best(curMove++, lastMove)->move;
return move;
case PH_EVASIONS:
case PH_QCAPTURES:
- move = pick_best(curMove++, lastMove).move;
+ move = pick_best(curMove++, lastMove)->move;
if (move != ttMove)
return move;
break;
+ case PH_QRECAPTURES:
+ move = (curMove++)->move;
+ if (move_to(move) == recaptureSquare)
+ return move;
+ break;
+
case PH_QCHECKS:
move = (curMove++)->move;
if (move != ttMove)