/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
- Copyright (C) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2004-2022 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
#include "movepick.h"
+namespace Stockfish {
+
namespace {
enum Stages {
/// MovePicker constructor for the main search
MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHistory* mh,
- const CapturePieceToHistory* cph, const PieceToHistory** ch, Move cm, Move* killers)
+ const CapturePieceToHistory* cph,
+ const PieceToHistory** ch,
+ Move cm,
+ const Move* killers)
: pos(p), mainHistory(mh), captureHistory(cph), continuationHistory(ch),
- refutations{{killers[0], 0}, {killers[1], 0}, {cm, 0}}, depth(d) {
-
+ ttMove(ttm), refutations{{killers[0], 0}, {killers[1], 0}, {cm, 0}}, depth(d)
+{
assert(d > 0);
- stage = pos.checkers() ? EVASION_TT : MAIN_TT;
- ttMove = ttm && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE;
- stage += (ttMove == MOVE_NONE);
+ stage = (pos.checkers() ? EVASION_TT : MAIN_TT) +
+ !(ttm && pos.pseudo_legal(ttm));
}
/// 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), 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;
- ttMove = ttm
- && (depth > DEPTH_QS_RECAPTURES || to_sq(ttm) == recaptureSquare)
- && pos.pseudo_legal(ttm) ? ttm : MOVE_NONE;
- stage += (ttMove == MOVE_NONE);
+ stage = (pos.checkers() ? EVASION_TT : QSEARCH_TT) +
+ !( ttm
+ && (pos.checkers() || depth > DEPTH_QS_RECAPTURES || to_sq(ttm) == recaptureSquare)
+ && 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), threshold(th) {
-
+MovePicker::MovePicker(const Position& p, Move ttm, Value th, Depth d, const CapturePieceToHistory* cph)
+ : pos(p), captureHistory(cph), ttMove(ttm), threshold(th), depth(d)
+{
assert(!pos.checkers());
- stage = PROBCUT_TT;
- ttMove = ttm
- && pos.capture(ttm)
- && pos.pseudo_legal(ttm)
- && pos.see_ge(ttm, threshold) ? ttm : MOVE_NONE;
- stage += (ttMove == MOVE_NONE);
+ stage = PROBCUT_TT + !(ttm && pos.capture(ttm)
+ && pos.pseudo_legal(ttm)
+ && pos.see_ge(ttm, threshold));
+}
+
+//squares threatened by pawn attacks
+template <Color Us>
+Bitboard threatsByPawn (const Position& pos)
+{
+ return pawn_attacks_bb<Us>(pos.pieces(Us, PAWN));
+}
+
+//squares threatened by minor attacks
+template <Color Us>
+Bitboard threatsByMinor (const Position& pos)
+{
+ Bitboard our = pos.pieces(Us, KNIGHT, BISHOP);
+ Bitboard threats = 0;
+ while (our)
+ {
+ Square s = pop_lsb(our);
+ if (type_of(pos.piece_on(s)) == KNIGHT)
+ threats |= attacks_bb<KNIGHT>(s, pos.pieces());
+ else
+ threats |= attacks_bb<BISHOP>(s, pos.pieces());
+ }
+ return threats;
+}
+
+//squares threatened by rook attacks
+template <Color Us>
+Bitboard threatsByRook (const Position& pos)
+{
+ Bitboard our = pos.pieces(Us, ROOK);
+ Bitboard threats = 0;
+ while (our)
+ {
+ Square s = pop_lsb(our);
+ threats |= attacks_bb<ROOK>(s, pos.pieces());
+ }
+ return threats;
}
/// MovePicker::score() assigns a numerical value to each move in a list, used
static_assert(Type == CAPTURES || Type == QUIETS || Type == EVASIONS, "Wrong type");
+ Bitboard threatened, threatenedByPawn, threatenedByMinor, threatenedByRook;
+ if constexpr (Type == QUIETS)
+ {
+ // squares threatened by pawns
+ threatenedByPawn = pos.side_to_move() == WHITE ? threatsByPawn<BLACK>(pos) : threatsByPawn<WHITE>(pos);
+ // squares threatened by minors or pawns
+ threatenedByMinor = pos.side_to_move() == WHITE ? threatsByMinor<BLACK>(pos) : threatsByMinor<WHITE>(pos);
+ threatenedByMinor |= threatenedByPawn;
+ // squares threatened by rooks, minors or pawns
+ threatenedByRook = pos.side_to_move() == WHITE ? threatsByRook<BLACK>(pos) : threatsByRook<WHITE>(pos);
+ threatenedByRook |= threatenedByMinor;
+
+ // pieces threatened by pieces of lesser material value
+ threatened = pos.side_to_move() == WHITE ? ((pos.pieces(WHITE, QUEEN) & threatenedByRook) |
+ (pos.pieces(WHITE, ROOK) & threatenedByMinor) |
+ (pos.pieces(WHITE, KNIGHT, BISHOP) & threatenedByPawn))
+ : ((pos.pieces(BLACK, QUEEN) & threatenedByRook) |
+ (pos.pieces(BLACK, ROOK) & threatenedByMinor) |
+ (pos.pieces(BLACK, KNIGHT, BISHOP) & threatenedByPawn));
+ }
+ else
+ {
+ // Silence unused variable warning
+ (void) threatened;
+ (void) threatenedByPawn;
+ (void) threatenedByMinor;
+ (void) threatenedByRook;
+ }
+
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)))];
+ if constexpr (Type == CAPTURES)
+ m.value = 6 * int(PieceValue[MG][pos.piece_on(to_sq(m))])
+ + (*captureHistory)[pos.moved_piece(m)][to_sq(m)][type_of(pos.piece_on(to_sq(m)))];
- else if (Type == QUIETS)
+ else if constexpr (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)];
+ + (*continuationHistory[1])[pos.moved_piece(m)][to_sq(m)]
+ + (*continuationHistory[3])[pos.moved_piece(m)][to_sq(m)]
+ + (*continuationHistory[5])[pos.moved_piece(m)][to_sq(m)]
+ + (threatened & from_sq(m) ?
+ (type_of(pos.piece_on(from_sq(m))) == QUEEN && !(to_sq(m) & threatenedByRook) ? 50000
+ : type_of(pos.piece_on(from_sq(m))) == ROOK && !(to_sq(m) & threatenedByMinor) ? 25000
+ : !(to_sq(m) & threatenedByPawn) ? 15000
+ : 0)
+ : 0);
else // Type == EVASIONS
{
m.value = PieceValue[MG][pos.piece_on(to_sq(m))]
- Value(type_of(pos.moved_piece(m)));
else
- m.value = (*mainHistory)[pos.side_to_move()][from_to(m)]
- + (*continuationHistory[0])[pos.moved_piece(m)][to_sq(m)]
+ m.value = (*mainHistory)[pos.side_to_move()][from_to(m)]
+ + 2 * (*continuationHistory[0])[pos.moved_piece(m)][to_sq(m)]
- (1 << 28);
}
}
}
/// 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, -3000 * depth);
++stage;
goto top;
case GOOD_CAPTURE:
- if (select<Best>([&](){
- return pos.see_ge(*cur, Value(-55 * cur->value / 1024)) ?
+ if (select<Next>([&](){
+ return pos.see_ge(*cur, Value(-69 * cur->value / 1024)) ?
// 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.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