// kingRing[color] is the zone around the king which is considered
// by the king safety evaluation. This consists of the squares directly
- // adjacent to the king, and the three (or two, for a king on an edge file)
+ // adjacent to the king, and (only for a king on its first rank) the
// squares two ranks in front of the king. For instance, if black's king
// is on g8, kingRing[BLACK] is a bitboard containing the squares f8, h8,
// f7, g7, h7, f6, g6 and h6.
};
const Score ThreatByRook[PIECE_TYPE_NB] = {
- S(0, 0), S(0, 25), S(40, 62), S(40, 59), S( 0, 34), S(35, 48)
+ S(0, 0), S(0, 25), S(40, 62), S(40, 59), S(0, 34), S(35, 48)
};
// ThreatByKing[on one/on many] contains bonuses for king attacks on
S(-20,-12), S( 1, -8), S( 2, 10), S( 9, 10)
};
- // Protector[PieceType-2][distance] contains a protecting bonus for our king,
- // indexed by piece type and distance between the piece and the king.
- const Score Protector[][8] = {
- { S(0, 0), S( 7, 9), S( 7, 1), S( 1, 5), S(-10,-4), S( -1,-4), S( -7,-3), S(-16,-10) }, // Knight
- { S(0, 0), S(11, 8), S(-7,-1), S(-1,-2), S( -1,-7), S(-11,-3), S( -9,-1), S(-16, -1) }, // Bishop
- { S(0, 0), S(10, 0), S(-2, 2), S(-5, 4), S( -6, 2), S(-14,-3), S( -2,-9), S(-12, -7) }, // Rook
- { S(0, 0), S( 3,-5), S( 2,-5), S(-4, 0), S( -9,-6), S( -4, 7), S(-13,-7), S(-10, -7) } // Queen
- };
+ // KingProtector[PieceType-2] contains a bonus according to distance from king
+ const Score KingProtector[] = { S(-3, -5), S(-4, -3), S(-3, 0), S(-1, 1) };
// Assorted bonuses and penalties used by evaluation
const Score MinorBehindPawn = S( 16, 0);
ei.attackedBy[Us][ALL_PIECES] = b | ei.attackedBy[Us][PAWN];
// Init our king safety tables only if we are going to use them
- if (pos.non_pawn_material(Them) >= QueenValueMg)
+ if (pos.non_pawn_material(Them) >= RookValueMg + KnightValueMg)
{
- ei.kingRing[Us] = b | shift<Up>(b);
+ ei.kingRing[Us] = b;
+ if (relative_rank(Us, pos.square<KING>(Us)) == RANK_1)
+ ei.kingRing[Us] |= shift<Up>(b);
+
ei.kingAttackersCount[Them] = popcount(b & ei.pe->pawn_attacks(Them));
ei.kingAdjacentZoneAttacksCount[Them] = ei.kingAttackersWeight[Them] = 0;
}
int mob = popcount(b & ei.mobilityArea[Us]);
- mobility[Us] += MobilityBonus[Pt-2][mob];
+ mobility[Us] += MobilityBonus[Pt - 2][mob];
// Bonus for this piece as a king protector
- score += Protector[Pt-2][distance(s, pos.square<KING>(Us))];
+ score += KingProtector[Pt - 2] * distance(s, pos.square<KING>(Us));
if (Pt == BISHOP || Pt == KNIGHT)
{
Score score = ei.pe->king_safety<Us>(pos, ksq);
// Main king safety evaluation
- if (ei.kingAttackersCount[Them])
+ if (ei.kingAttackersCount[Them] > (1 - pos.count<QUEEN>(Them)))
{
// Find the attacked squares which are defended only by our king...
undefended = ei.attackedBy[Them][ALL_PIECES]
+ 201 * popcount(undefended)
+ 143 * (popcount(b) + !!pos.pinned_pieces(Us))
- 848 * !pos.count<QUEEN>(Them)
- - 28 * mg_value(score) / 25 - 5;
+ - 9 * mg_value(score) / 8
+ + 40;
// Analyse the safe enemy's checks which are possible on next move
safe = ~pos.pieces(Them);
safe &= ~ei.attackedBy[Us][ALL_PIECES] | (undefended & ei.attackedBy2[Them]);
- b1 = pos.attacks_from<ROOK >(ksq);
+ b1 = pos.attacks_from< ROOK>(ksq);
b2 = pos.attacks_from<BISHOP>(ksq);
// Enemy queen safe checks
// Transform the kingDanger units into a Score, and substract it from the evaluation
if (kingDanger > 0)
- score -= make_score(kingDanger * kingDanger / 4096, 0);
+ score -= make_score(kingDanger * kingDanger / 4096, kingDanger / 16);
}
// King tropism: firstly, find squares that opponent attacks in our king flank
// Adjust bonus based on the king's proximity
ebonus += distance(pos.square<KING>(Them), blockSq) * 5 * rr
- - distance(pos.square<KING>(Us ), blockSq) * 2 * rr;
+ - distance(pos.square<KING>( Us), blockSq) * 2 * rr;
// If blockSq is not the queening square then consider also a second push
if (relative_rank(Us, blockSq) != RANK_8)
<< " Imbalance | " << Term(IMBALANCE)
<< " Pawns | " << Term(PAWN)
<< " Knights | " << Term(KNIGHT)
- << " Bishop | " << Term(BISHOP)
+ << " Bishops | " << Term(BISHOP)
<< " Rooks | " << Term(ROOK)
<< " Queens | " << Term(QUEEN)
<< " Mobility | " << Term(MOBILITY)