Try only recaptures in qsearch if depth is very low

This avoids search explosion in qsearch for some
patological cases like:

r1n1n1b1/1P1P1P1P/1N1N1N2/2RnQrRq/2pKp3/3BNQbQ/k7/4Bq2 w - - 0 1

After 9078 games 20"+0.1 QUAD:
Mod vs Orig 1413 - 1319 - 6346 ELO +3 (+- 4)

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2011-06-12 07:25:51 +01:00
parent 15683034a7
commit 72760c05c6
4 changed files with 27 additions and 7 deletions

View File

@@ -1393,7 +1393,7 @@ split_point_start: // At split points actual search starts from here
// to search the moves. Because the depth is <= 0 here, only captures,
// queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will
// be generated.
MovePicker mp(pos, ttMove, depth, H);
MovePicker mp(pos, ttMove, depth, H, move_to((ss-1)->currentMove));
CheckInfo ci(pos);
Bitboard pinned = pos.pinned_pieces(pos.side_to_move());