If the null move was refuted by a capture then give a
bonus if we move away the captured piece.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
mateKiller = (ss.mateKiller == ttm)? MOVE_NONE : ss.mateKiller;
killer1 = ss.killers[0];
killer2 = ss.killers[1];
+ threatMove = ss.threatMove;
depth = d;
movesPicked = 0;
numOfMoves = 0;
else
hs = H.move_ordering_score(pos.piece_on(move_from(m)), m);
- // Ensure moves in history are always sorted as first
+ // If the null move was refuted by a capture then give a
+ // bonus if we move away the captured piece.
+ if (threatMove != MOVE_NONE && move_from(m) == move_to(threatMove))
+ hs *= 3;
+
+ // Ensure history is always preferred to pst
if (hs > 0)
hs += 1000;
+ // pst based scoring
moves[i].score = hs + pos.mg_pst_delta(m);
}
}
int find_best_index(Bitboard* squares, int values[]);
const Position& pos;
- Move ttMove, mateKiller, killer1, killer2;
+ Move ttMove, mateKiller, killer1, killer2, threatMove;
Bitboard pinned, dc;
MoveStack moves[256], badCaptures[64];
bool pvNode;