// Outpost[knight/bishop][supported by pawn] contains bonuses for knights and
// bishops outposts, bigger if outpost piece is supported by a pawn.
const Score Outpost[][2] = {
- { S(28, 7), S(42,11) }, // Knights
- { S(12, 3), S(18, 5) } // Bishops
+ { S(42,11), S(63,17) }, // Knights
+ { S(18, 5), S(27, 8) } // Bishops
};
- // Threat[defended/weak][minor/major attacking][attacked PieceType] contains
+ // Threat[defended/weak][minor/rook attacking][attacked PieceType] contains
// bonuses according to which piece type attacks which one.
const Score Threat[][2][PIECE_TYPE_NB] = {
- { { S(0, 0), S( 0, 0), S(19, 37), S(24, 37), S(44, 97), S(35,106) }, // Defended Minor
- { S(0, 0), S( 0, 0), S( 9, 14), S( 9, 14), S( 7, 14), S(24, 48) } }, // Defended Major
- { { S(0, 0), S( 0,32), S(33, 41), S(31, 50), S(41,100), S(35,104) }, // Weak Minor
- { S(0, 0), S( 0,27), S(26, 57), S(26, 57), S(0 , 43), S(23, 51) } } // Weak Major
+ { { S(0, 0), S( 0, 0), S(19, 37), S(24, 37), S(44, 97), S(35,106) }, // Minor on Defended
+ { S(0, 0), S( 0, 0), S( 9, 14), S( 9, 14), S( 7, 14), S(24, 48) } }, // Rook on Defended
+ { { S(0, 0), S( 0,32), S(33, 41), S(31, 50), S(41,100), S(35,104) }, // Minor on Weak
+ { S(0, 0), S( 0,27), S(26, 57), S(26, 57), S(0 , 43), S(23, 51) } } // Rook on Weak
};
// ThreatenedByPawn[PieceType] contains a penalty according to which piece
{ V(7), V(14), V(37), V(63), V(134), V(189) }
};
+ // PassedFile[File] contains a bonus according to the file of a passed pawn.
+ const Score PassedFile[] = {
+ S( 14, 13), S( 2, 5), S(-3, -4), S(-19, -14),
+ S(-19, -14), S(-3, -4), S( 2, 5), S( 14, 13)
+ };
+
const Score ThreatenedByHangingPawn = S(40, 60);
// Assorted bonuses and penalties used by evaluation
const Score Unstoppable = S( 0, 20);
const Score Hanging = S(31, 26);
const Score PawnAttackThreat = S(20, 20);
+ const Score Checked = S(20, 20);
// Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
// a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
// Penalties for enemy's safe checks
const int QueenContactCheck = 89;
- const int RookContactCheck = 71;
const int QueenCheck = 50;
- const int RookCheck = 37;
+ const int RookCheck = 45;
const int BishopCheck = 6;
const int KnightCheck = 14;
// evaluate_pieces() assigns bonuses and penalties to the pieces of a given color
template<PieceType Pt, Color Us, bool DoTrace>
- Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, Bitboard* mobilityArea) {
+ Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, const Bitboard* mobilityArea) {
Bitboard b;
Square s;
{
// Bonus for outpost square
if ( relative_rank(Us, s) >= RANK_4
+ && relative_rank(Us, s) <= RANK_6
&& !(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s)))
score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)];
}
template<>
- Score evaluate_pieces<KING, WHITE, false>(const Position&, EvalInfo&, Score*, Bitboard*) { return SCORE_ZERO; }
+ Score evaluate_pieces<KING, WHITE, false>(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; }
template<>
- Score evaluate_pieces<KING, WHITE, true>(const Position&, EvalInfo&, Score*, Bitboard*) { return SCORE_ZERO; }
+ Score evaluate_pieces<KING, WHITE, true>(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; }
// evaluate_king() assigns bonuses and penalties to a king of a given color
// number and types of the enemy's attacking pieces, the number of
// attacked and undefended squares around our king and the quality of
// the pawn shelter (current 'score' value).
- attackUnits = std::min(74, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
- + 8 * ei.kingAdjacentZoneAttacksCount[Them]
- + 25 * popcount<Max15>(undefended)
+ attackUnits = std::min(72, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
+ + 9 * ei.kingAdjacentZoneAttacksCount[Them]
+ + 27 * popcount<Max15>(undefended)
+ 11 * !!ei.pinnedPieces[Us]
- - 60 * !pos.count<QUEEN>(Them)
+ - 64 * !pos.count<QUEEN>(Them)
- mg_value(score) / 8;
// Analyse the enemy's safe queen contact checks. Firstly, find the
attackUnits += QueenContactCheck * popcount<Max15>(b);
}
- // Analyse the enemy's safe rook contact checks. Firstly, find the
- // undefended squares around the king reachable by the enemy rooks...
- b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
-
- // Consider only squares where the enemy's rook gives check
- b &= PseudoAttacks[ROOK][ksq];
-
- if (b)
- {
- // ...and then remove squares not supported by another enemy piece
- b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
- | ei.attackedBy[Them][BISHOP]);
-
- if (b)
- attackUnits += RookContactCheck * popcount<Max15>(b);
- }
-
// Analyse the enemy's safe distance checks for sliders and knights
safe = ~(ei.attackedBy[Us][ALL_PIECES] | pos.pieces(Them));
// Enemy queen safe checks
b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
if (b)
+ {
attackUnits += QueenCheck * popcount<Max15>(b);
+ score -= Checked;
+ }
// Enemy rooks safe checks
b = b1 & ei.attackedBy[Them][ROOK];
if (b)
+ {
attackUnits += RookCheck * popcount<Max15>(b);
+ score -= Checked;
+ }
// Enemy bishops safe checks
b = b2 & ei.attackedBy[Them][BISHOP];
if (b)
+ {
attackUnits += BishopCheck * popcount<Max15>(b);
+ score -= Checked;
+ }
// Enemy knights safe checks
b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
if (b)
+ {
attackUnits += KnightCheck * popcount<Max15>(b);
+ score -= Checked;
+ }
// Finally, extract the king danger score from the KingDanger[]
// array and subtract the score from evaluation.
const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
enum { Defended, Weak };
- enum { Minor, Major };
+ enum { Minor, Rook };
Bitboard b, weak, defended, safeThreats;
Score score = SCORE_ZERO;
while (b)
score += Threat[Defended][Minor][type_of(pos.piece_on(pop_lsb(&b)))];
- b = defended & (ei.attackedBy[Us][ROOK]);
+ b = defended & ei.attackedBy[Us][ROOK];
while (b)
- score += Threat[Defended][Major][type_of(pos.piece_on(pop_lsb(&b)))];
+ score += Threat[Defended][Rook][type_of(pos.piece_on(pop_lsb(&b)))];
}
// Enemies not defended by a pawn and under our attack
while (b)
score += Threat[Weak][Minor][type_of(pos.piece_on(pop_lsb(&b)))];
- b = weak & (ei.attackedBy[Us][ROOK] | ei.attackedBy[Us][QUEEN]);
+ b = weak & ei.attackedBy[Us][ROOK];
while (b)
- score += Threat[Weak][Major][type_of(pos.piece_on(pop_lsb(&b)))];
+ score += Threat[Weak][Rook][type_of(pos.piece_on(pop_lsb(&b)))];
b = weak & ~ei.attackedBy[Them][ALL_PIECES];
if (b)
// If there aren't any enemy attacks, assign a big bonus. Otherwise
// assign a smaller bonus if the block square isn't attacked.
- int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 0;
+ int k = !unsafeSquares ? 18 : !(unsafeSquares & blockSq) ? 8 : 0;
// If the path to queen is fully defended, assign a big bonus.
// Otherwise assign a smaller bonus if the block square is defended.
if (pos.count<PAWN>(Us) < pos.count<PAWN>(Them))
ebonus += ebonus / 4;
- score += make_score(mbonus, ebonus);
+ score += make_score(mbonus, ebonus) + PassedFile[file_of(s)];
}
if (DoTrace)
return make_score(bonus * weight * weight, 0);
}
+
+ // evaluate_initiative() computes the initiative correction value for the position, i.e.
+ // second order bonus/malus based on the known attacking/defending status of the players.
+ Score evaluate_initiative(const Position& pos, const EvalInfo& ei, const Score positional_score) {
+
+ int pawns = pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK);
+ int king_separation = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
+ int asymmetry = ei.pi->pawn_asymmetry();
+
+ // Compute the initiative bonus for the attacking side
+ int attacker_bonus = 8 * (pawns + asymmetry + king_separation) - 120;
+
+ // Now apply the bonus: note that we find the attacking side by extracting the sign
+ // of the endgame value of "positional_score", and that we carefully cap the bonus so
+ // that the endgame score with the correction will never be divided by more than two.
+ int eg = eg_value(positional_score);
+ int value = ((eg > 0) - (eg < 0)) * std::max( attacker_bonus , -abs( eg / 2 ) );
+
+ return make_score( 0 , value ) ;
+ }
+
} // namespace
}
// Evaluate space for both sides, only during opening
- if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= 11756)
+ if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= 12222)
score += (evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei)) * Weights[Space];
+
+ // Evaluate initiative
+ score += evaluate_initiative(pos, ei, score);
// Scale winning side if position is more drawish than it appears
Color strongSide = eg_value(score) > VALUE_DRAW ? WHITE : BLACK;
// is almost a draw, in case of KBP vs KB is even more a draw.
if ( pos.non_pawn_material(WHITE) == BishopValueMg
&& pos.non_pawn_material(BLACK) == BishopValueMg)
- sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(32) : ScaleFactor(8);
+ sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(31) : ScaleFactor(9);
// Endgame with opposite-colored bishops, but also other pieces. Still
// a bit drawish, but not as drawish as with only the two bishops.
else
- sf = ScaleFactor(50 * sf / SCALE_FACTOR_NORMAL);
+ sf = ScaleFactor(46 * sf / SCALE_FACTOR_NORMAL);
}
// Endings where weaker side can place his king in front of the opponent's
// pawns are drawish.
else if ( abs(eg_value(score)) <= BishopValueEg
&& ei.pi->pawn_span(strongSide) <= 1
&& !pos.pawn_passed(~strongSide, pos.square<KING>(~strongSide)))
- sf = ei.pi->pawn_span(strongSide) ? ScaleFactor(56) : ScaleFactor(38);
+ sf = ei.pi->pawn_span(strongSide) ? ScaleFactor(51) : ScaleFactor(37);
}
// Interpolate between a middlegame and a (scaled by 'sf') endgame score
projects / stockfish / blobdiff