public static void MovePicker.score()
{
// Try good captures ordered by MVV/LVA, then non-captures if destination square
// is not under attack, ordered by history value, then bad-captures and quiet
// moves with a negative SEE. This last group is ordered by the SEE value.
Move m;
Value see;
for (ExtMove *it = moves; it != end; ++it)
{
m = it.move;
if ((see = pos.see_sign(m)) < Value.VALUE_ZERO)
{
it.value = see - Stats <false, Value> .Max; // At the bottom
}
else if (pos.capture(m))
{
it.value = GlobalMembersPosition.PieceValue[(int)Phase.MG, pos.piece_on(GlobalMembersTypes.to_sq(m))] - Value(GlobalMembersTypes.type_of(pos.moved_piece(m))) + Stats <false, Value> .Max;
}
else
{
it.value = history[pos.moved_piece(m)][(int)GlobalMembersTypes.to_sq(m)];
}
}
}
/// score() assign a numerical value to each move in a move list. The moves with
/// highest values will be picked first.
public static void MovePicker.score()
{
// Winning and equal captures in the main search are ordered by MVV/LVA.
// Suprisingly, this appears to perform slightly better than SEE based
// move ordering. The reason is probably that in a position with a winning
// capture, capturing a more valuable (but sufficiently defended) piece
// first usually doesn't hurt. The opponent will have to recapture, and
// the hanging piece will still be hanging (except in the unusual cases
// where it is possible to recapture with the hanging piece). Exchanging
// big pieces before capturing a hanging piece probably helps to reduce
// the subtree size.
// In main search we want to push captures with negative SEE values to the
// badCaptures[] array, but instead of doing it now we delay until the move
// has been picked up in pick_move_from_list(). This way we save some SEE
// calls in case we get a cutoff.
Move m;
for (ExtMove *it = moves; it != end; ++it)
{
m = it.move;
it.value = GlobalMembersPosition.PieceValue[(int)Phase.MG, pos.piece_on(GlobalMembersTypes.to_sq(m))] - Value(GlobalMembersTypes.type_of(pos.moved_piece(m)));
if (GlobalMembersTypes.type_of(m) == MoveType.ENPASSANT)
{
it.value += GlobalMembersPosition.PieceValue[(int)Phase.MG, (int)PieceType.PAWN];
}
else if (GlobalMembersTypes.type_of(m) == MoveType.PROMOTION)
{
it.value += GlobalMembersPosition.PieceValue[(int)Phase.MG, (int)GlobalMembersTypes.promotion_type(m)] - GlobalMembersPosition.PieceValue[(int)Phase.MG, (int)PieceType.PAWN];
}
}
}
public static void MovePicker.score()
{
Move m;
for (ExtMove *it = moves; it != end; ++it)
{
m = it.move;
it.value = history[pos.moved_piece(m)][(int)GlobalMembersTypes.to_sq(m)];
}
}
