/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2020 The Stockfish developers (see AUTHORS file)
+ Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file)
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include "movepick.h"
+
+#include <algorithm>
#include <cassert>
+#include <iterator>
+#include <utility>
-#include "movepick.h"
+#include "bitboard.h"
+#include "position.h"
+
+namespace Stockfish {
namespace {
} // namespace
-/// Constructors of the MovePicker class. As arguments we pass information
-/// to help it to return the (presumably) good moves first, to decide which
+/// Constructors of the MovePicker class. As arguments, we pass information
+/// to help it 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 how important good move
-/// ordering is at the current node.
+/// search captures, promotions, and some checks) and how important a good
+/// move ordering is at the current node.
/// MovePicker constructor for the main search
-MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh, const LowPlyHistory* lp,
- const CapturePieceToHistory* cph, const PieceToHistory** ch, Move cm, const Move* killers, int pl)
- : pos(p), mainHistory(mh), lowPlyHistory(lp), captureHistory(cph), continuationHistory(ch),
- ttMove(ttm), refutations{{killers[0], 0}, {killers[1], 0}, {cm, 0}}, depth(d), ply(pl) {
-
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh,
+ const CapturePieceToHistory* cph,
+ const PieceToHistory** ch,
+ Move cm,
+ const Move* killers)
+ : pos(p), mainHistory(mh), captureHistory(cph), continuationHistory(ch),
+ ttMove(ttm), refutations{{killers[0], 0}, {killers[1], 0}, {cm, 0}}, depth(d)
+{
assert(d > 0);
stage = (pos.checkers() ? EVASION_TT : MAIN_TT) +
/// MovePicker constructor for quiescence search
MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh,
- const CapturePieceToHistory* cph, const PieceToHistory** ch, Square rs)
- : pos(p), mainHistory(mh), captureHistory(cph), continuationHistory(ch), ttMove(ttm), recaptureSquare(rs), depth(d) {
-
+ const CapturePieceToHistory* cph,
+ const PieceToHistory** ch,
+ Square rs)
+ : pos(p), mainHistory(mh), captureHistory(cph), continuationHistory(ch), ttMove(ttm), recaptureSquare(rs), depth(d)
+{
assert(d <= 0);
stage = (pos.checkers() ? EVASION_TT : QSEARCH_TT) +
- !(ttm && (depth > DEPTH_QS_RECAPTURES || to_sq(ttm) == recaptureSquare)
- && pos.pseudo_legal(ttm));
+ !( ttm
+ && pos.pseudo_legal(ttm));
}
/// MovePicker constructor for ProbCut: we generate captures with SEE greater
/// than or equal to the given threshold.
MovePicker::MovePicker(const Position& p, Move ttm, Value th, const CapturePieceToHistory* cph)
- : pos(p), captureHistory(cph), ttMove(ttm), threshold(th) {
-
+ : pos(p), captureHistory(cph), ttMove(ttm), threshold(th)
+{
assert(!pos.checkers());
- stage = PROBCUT_TT + !(ttm && pos.capture(ttm)
+ stage = PROBCUT_TT + !(ttm && pos.capture_stage(ttm)
&& pos.pseudo_legal(ttm)
&& pos.see_ge(ttm, threshold));
}
/// MovePicker::score() assigns a numerical value to each move in a list, used
/// for sorting. Captures are ordered by Most Valuable Victim (MVV), preferring
-/// captures with a good history. Quiets moves are ordered using the histories.
+/// captures with a good history. Quiets moves are ordered using the history tables.
template<GenType Type>
void MovePicker::score() {
static_assert(Type == CAPTURES || Type == QUIETS || Type == EVASIONS, "Wrong type");
+ [[maybe_unused]] Bitboard threatenedByPawn, threatenedByMinor, threatenedByRook, threatenedPieces;
+ if constexpr (Type == QUIETS)
+ {
+ Color us = pos.side_to_move();
+
+ threatenedByPawn = pos.attacks_by<PAWN>(~us);
+ threatenedByMinor = pos.attacks_by<KNIGHT>(~us) | pos.attacks_by<BISHOP>(~us) | threatenedByPawn;
+ threatenedByRook = pos.attacks_by<ROOK>(~us) | threatenedByMinor;
+
+ // Pieces threatened by pieces of lesser material value
+ threatenedPieces = (pos.pieces(us, QUEEN) & threatenedByRook)
+ | (pos.pieces(us, ROOK) & threatenedByMinor)
+ | (pos.pieces(us, KNIGHT, BISHOP) & threatenedByPawn);
+ }
+
for (auto& m : *this)
- if (Type == CAPTURES)
- m.value = int(PieceValue[MG][pos.piece_on(to_sq(m))]) * 6
- + (*captureHistory)[pos.moved_piece(m)][to_sq(m)][type_of(pos.piece_on(to_sq(m)))];
-
- else if (Type == QUIETS)
- m.value = (*mainHistory)[pos.side_to_move()][from_to(m)]
- + 2 * (*continuationHistory[0])[pos.moved_piece(m)][to_sq(m)]
- + 2 * (*continuationHistory[1])[pos.moved_piece(m)][to_sq(m)]
- + 2 * (*continuationHistory[3])[pos.moved_piece(m)][to_sq(m)]
- + (*continuationHistory[5])[pos.moved_piece(m)][to_sq(m)]
- + (ply < MAX_LPH ? std::min(4, depth / 3) * (*lowPlyHistory)[ply][from_to(m)] : 0);
+ if constexpr (Type == CAPTURES)
+ m.value = (7 * int(PieceValue[pos.piece_on(to_sq(m))])
+ + (*captureHistory)[pos.moved_piece(m)][to_sq(m)][type_of(pos.piece_on(to_sq(m)))]) / 16;
+
+ else if constexpr (Type == QUIETS)
+ {
+ Piece pc = pos.moved_piece(m);
+ PieceType pt = type_of(pos.moved_piece(m));
+ Square from = from_sq(m);
+ Square to = to_sq(m);
+
+ // histories
+ m.value = 2 * (*mainHistory)[pos.side_to_move()][from_to(m)];
+ m.value += 2 * (*continuationHistory[0])[pc][to];
+ m.value += (*continuationHistory[1])[pc][to];
+ m.value += (*continuationHistory[2])[pc][to] / 4;
+ m.value += (*continuationHistory[3])[pc][to];
+ m.value += (*continuationHistory[5])[pc][to];
+
+ // bonus for checks
+ m.value += bool(pos.check_squares(pt) & to) * 16384;
+
+ // bonus for escaping from capture
+ m.value += threatenedPieces & from ?
+ (pt == QUEEN && !(to & threatenedByRook) ? 50000
+ : pt == ROOK && !(to & threatenedByMinor) ? 25000
+ : !(to & threatenedByPawn) ? 15000
+ : 0 )
+ : 0 ;
+
+ // malus for putting piece en prise
+ m.value -= !(threatenedPieces & from) ?
+ (pt == QUEEN ? bool(to & threatenedByRook) * 50000
+ + bool(to & threatenedByMinor) * 10000
+ + bool(to & threatenedByPawn) * 20000
+ : pt == ROOK ? bool(to & threatenedByMinor) * 25000
+ + bool(to & threatenedByPawn) * 10000
+ : pt != PAWN ? bool(to & threatenedByPawn) * 15000
+ : 0 )
+ : 0 ;
+ }
else // Type == EVASIONS
{
- if (pos.capture(m))
- m.value = PieceValue[MG][pos.piece_on(to_sq(m))]
- - Value(type_of(pos.moved_piece(m)));
+ if (pos.capture_stage(m))
+ m.value = PieceValue[pos.piece_on(to_sq(m))]
+ - Value(type_of(pos.moved_piece(m)))
+ + (1 << 28);
else
m.value = (*mainHistory)[pos.side_to_move()][from_to(m)]
- + (*continuationHistory[0])[pos.moved_piece(m)][to_sq(m)]
- - (1 << 28);
+ + (*continuationHistory[0])[pos.moved_piece(m)][to_sq(m)];
}
}
while (cur < endMoves)
{
- if (T == Best)
+ if constexpr (T == Best)
std::swap(*cur, *std::max_element(cur, endMoves));
if (*cur != ttMove && filter())
}
/// 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
+/// returns a new pseudo-legal move every time it is called until there are no more
/// moves left, picking the move with the highest score from a list of generated moves.
Move MovePicker::next_move(bool skipQuiets) {
endMoves = generate<CAPTURES>(pos, cur);
score<CAPTURES>();
+ partial_insertion_sort(cur, endMoves, std::numeric_limits<int>::min());
++stage;
goto top;
case GOOD_CAPTURE:
- if (select<Best>([&](){
- return pos.see_ge(*cur, Value(-69 * cur->value / 1024)) ?
+ if (select<Next>([&](){
+ return pos.see_ge(*cur, Value(-cur->value)) ?
// Move losing capture to endBadCaptures to be tried later
true : (*endBadCaptures++ = *cur, false); }))
return *(cur - 1);
--endMoves;
++stage;
- /* fallthrough */
+ [[fallthrough]];
case REFUTATION:
if (select<Next>([&](){ return *cur != MOVE_NONE
- && !pos.capture(*cur)
+ && !pos.capture_stage(*cur)
&& pos.pseudo_legal(*cur); }))
return *(cur - 1);
++stage;
- /* fallthrough */
+ [[fallthrough]];
case QUIET_INIT:
if (!skipQuiets)
}
++stage;
- /* fallthrough */
+ [[fallthrough]];
case QUIET:
if ( !skipQuiets
endMoves = endBadCaptures;
++stage;
- /* fallthrough */
+ [[fallthrough]];
case BAD_CAPTURE:
return select<Next>([](){ return true; });
score<EVASIONS>();
++stage;
- /* fallthrough */
+ [[fallthrough]];
case EVASION:
return select<Best>([](){ return true; });
case PROBCUT:
- return select<Best>([&](){ return pos.see_ge(*cur, threshold); });
+ return select<Next>([&](){ return pos.see_ge(*cur, threshold); });
case QCAPTURE:
- if (select<Best>([&](){ return depth > DEPTH_QS_RECAPTURES
+ if (select<Next>([&](){ return depth > DEPTH_QS_RECAPTURES
|| to_sq(*cur) == recaptureSquare; }))
return *(cur - 1);
return MOVE_NONE;
++stage;
- /* fallthrough */
+ [[fallthrough]];
case QCHECK_INIT:
cur = moves;
endMoves = generate<QUIET_CHECKS>(pos, cur);
++stage;
- /* fallthrough */
+ [[fallthrough]];
case QCHECK:
return select<Next>([](){ return true; });
assert(false);
return MOVE_NONE; // Silence warning
}
+
+} // namespace Stockfish
projects / stockfish / blobdiff