value += pc * v;
}
+
+ // Queen vs. 3 minors slightly favours the minors
+ if (pieceCount[Us][QUEEN] == 1 && pieceCount[Them][QUEEN] == 0)
+ {
+ int n = pieceCount[Them][KNIGHT] - pieceCount[Us][KNIGHT];
+ int b = pieceCount[Them][BISHOP] - pieceCount[Us][BISHOP];
+
+ if ((n == 2 && b == 1) || (n == 1 && b == 2))
+ value -= 66 * 16;
+ }
+
return value;
}
return e;
}
- // Generic scaling functions that refer to more then one material
+ // Generic scaling functions that refer to more than one material
// distribution. They should be probed after the specialized ones.
// Note that these ones don't return after setting the function.
if (is_KBPsKs<WHITE>(pos))
// catches some trivial draws like KK, KBK and KNK and gives a very drawish
// scale factor for cases such as KRKBP and KmmKm (except for KBBKN).
if (!pos.count<PAWN>(WHITE) && npm_w - npm_b <= BishopValueMg)
- {
- e->factor[WHITE] = npm_w < RookValueMg ? 0 : npm_b <= BishopValueMg ? 4 : 12;
- }
+ e->factor[WHITE] = uint8_t(npm_w < RookValueMg ? SCALE_FACTOR_DRAW : npm_b <= BishopValueMg ? 4 : 12);
if (!pos.count<PAWN>(BLACK) && npm_b - npm_w <= BishopValueMg)
- {
- e->factor[BLACK] = npm_b < RookValueMg ? 0 : npm_w <= BishopValueMg ? 4 : 12;
- }
+ e->factor[BLACK] = uint8_t(npm_b < RookValueMg ? SCALE_FACTOR_DRAW : npm_w <= BishopValueMg ? 4 : 12);
if (pos.count<PAWN>(WHITE) == 1 && npm_w - npm_b <= BishopValueMg)
- {
e->factor[WHITE] = (uint8_t) SCALE_FACTOR_ONEPAWN;
- }
if (pos.count<PAWN>(BLACK) == 1 && npm_b - npm_w <= BishopValueMg)
- {
e->factor[BLACK] = (uint8_t) SCALE_FACTOR_ONEPAWN;
- }
// Compute the space weight
if (npm_w + npm_b >= 2 * QueenValueMg + 4 * RookValueMg + 2 * KnightValueMg)