/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2009 Marco Costalba
+ Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
/// search captures, promotions and some checks) and about how important good
/// move ordering is at the current node.
-MovePicker::MovePicker(const Position& p, Move ttm, Depth d,
- const History& h, SearchStack* ss) : pos(p), H(h) {
+MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h,
+ SearchStack* ss, Value beta) : pos(p), H(h) {
int searchTT = ttm;
ttMoves[0].move = ttm;
+ badCaptureThreshold = 0;
lastBadCapture = badCaptures;
pinned = p.pinned_pieces(pos.side_to_move());
if (ss && !p.is_check())
{
- ttMoves[1].move = (ss->mateKiller == ttm)? MOVE_NONE : ss->mateKiller;
+ ttMoves[1].move = (ss->mateKiller == ttm) ? MOVE_NONE : ss->mateKiller;
searchTT |= ttMoves[1].move;
killers[0].move = ss->killers[0];
killers[1].move = ss->killers[1];
if (p.is_check())
phasePtr = EvasionsPhaseTable;
else if (d > Depth(0))
+ {
+ // Consider sligtly negative captures as good if at low
+ // depth and far from beta.
+ if (ss && ss->eval < beta - PawnValueMidgame && d < 3 * OnePly)
+ badCaptureThreshold = -PawnValueMidgame;
+
phasePtr = MainSearchPhaseTable;
+ }
else if (d == Depth(0))
phasePtr = QsearchWithChecksPhaseTable;
else
searchTT = ttMoves[0].move = MOVE_NONE;
}
- phasePtr += !searchTT - 1;
+ phasePtr += int(!searchTT) - 1;
go_next_phase();
}
from = move_from(m);
to = move_to(m);
piece = pos.piece_on(from);
- cur->score = H.move_ordering_score(piece, to);
+ cur->score = H.value(piece, to) + H.gain(piece, to);
}
}
cur->score = pos.midgame_value_of_piece_on(move_to(m))
- pos.type_of_piece_on(move_from(m)) + HistoryMax;
else
- cur->score = H.move_ordering_score(pos.piece_on(move_from(m)), move_to(m));
+ cur->score = H.value(pos.piece_on(move_from(m)), move_to(m));
}
}
{
// Check for a non negative SEE now
int seeValue = pos.see_sign(move);
- if (seeValue >= 0)
+ if (seeValue >= badCaptureThreshold)
return move;
// Losing capture, move it to the badCaptures[] array, note
case PH_KILLERS:
move = (curMove++)->move;
if ( move != MOVE_NONE
+ && move_is_legal(pos, move, pinned)
&& move != ttMoves[0].move
&& move != ttMoves[1].move
- && move_is_legal(pos, move, pinned)
&& !pos.move_is_capture(move))
return move;
break;