+ 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];
return e;
}
- // Draw by insufficient material (trivial draws like KK, KBK and KNK)
- if ( !pos.pieces(PAWN)
- && pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) <= BishopValueMg)
- {
- e->evaluationFunction = &EvaluateKmmKm[pos.side_to_move()];
- return e;
- }
-
- // Minor piece endgame with at least one minor piece per side and
- // no pawns. Note that the case KmmK is already handled by KXK.
if (!pos.pieces(PAWN) && !pos.pieces(ROOK) && !pos.pieces(QUEEN))
{
+ // Minor piece endgame with at least one minor piece per side and
+ // no pawns. Note that the case KmmK is already handled by KXK.
assert((pos.pieces(WHITE, KNIGHT) | pos.pieces(WHITE, BISHOP)));
assert((pos.pieces(BLACK, KNIGHT) | pos.pieces(BLACK, BISHOP)));
}
}
- // 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)