const Value RedundantRook = Value(554);
// pair pawn knight bishop rook queen
- const int LinearCoefficients[6] = { 1617, -162, -1172, -190, 105, 26 };
+ const int LinearCoefficients[6] = { 1817, -162, -1122, -190, 105, 26 };
const int QuadraticCoefficientsSameColor[][PIECE_TYPE_NB] = {
// pair pawn knight bishop rook queen
+ RedundantQueen * pieceCount[Us][QUEEN];
// Second-degree polynomial material imbalance by Tord Romstad
- for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; pt1++)
+ for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1)
{
pc = pieceCount[Us][pt1];
if (!pc)
v = LinearCoefficients[pt1];
- for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; pt2++)
+ for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2)
v += QuadraticCoefficientsSameColor[pt1][pt2] * pieceCount[Us][pt2]
+ QuadraticCoefficientsOppositeColor[pt1][pt2] * pieceCount[Them][pt2];
}
}
- // No pawns makes it difficult to win, even with a material advantage
+ // No pawns makes it difficult to win, even with a material advantage. This
+ // catches some trivial draws like KK, KBK and KNK
if (!pos.count<PAWN>(WHITE) && npm_w - npm_b <= BishopValueMg)
{
e->factor[WHITE] = (uint8_t)