For a good quiet non-pawn move consider the reverse move as bad
and update the main history with a negative stat bonus.
STC:
LLR: 2.95 (-2.94,2.94) [0.50,4.50]
Total: 19292 W: 4401 L: 4141 D: 10750
http://tests.stockfishchess.org/tests/view/
5d7751d50ebc594e7864973c
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 111952 W: 18762 L: 18275 D: 74915
http://tests.stockfishchess.org/tests/view/
5d7771cf0ebc594e786498fa
Closes https://github.com/official-stockfish/Stockfish/pull/2294
Bench:
3914238
// castling moves, because they are coded as "king captures rook" and
// hence break make_move(). (~5 Elo)
else if ( type_of(move) == NORMAL
- && !pos.see_ge(make_move(to_sq(move), from_sq(move))))
+ && !pos.see_ge(reverse_move(move)))
r -= 2 * ONE_PLY;
ss->statScore = thisThread->mainHistory[us][from_to(move)]
thisThread->mainHistory[us][from_to(move)] << bonus;
update_continuation_histories(ss, pos.moved_piece(move), to_sq(move), bonus);
+ if (type_of(pos.moved_piece(move)) != PAWN)
+ thisThread->mainHistory[us][from_to(reverse_move(move))] << -bonus;
+
if (is_ok((ss-1)->currentMove))
{
Square prevSq = to_sq((ss-1)->currentMove);
return Move((from << 6) + to);
}
+constexpr Move reverse_move(Move m) {
+ return make_move(to_sq(m), from_sq(m));
+}
+
template<MoveType T>
constexpr Move make(Square from, Square to, PieceType pt = KNIGHT) {
return Move(T + ((pt - KNIGHT) << 12) + (from << 6) + to);