Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
- Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+ Copyright (C) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
constexpr Value SpaceThreshold = Value(12222);
// KingAttackWeights[PieceType] contains king attack weights by piece type
- constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 77, 55, 44, 10 };
+ constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 81, 52, 44, 10 };
// Penalties for enemy's safe checks
- constexpr int QueenSafeCheck = 780;
- constexpr int RookSafeCheck = 1080;
- constexpr int BishopSafeCheck = 635;
- constexpr int KnightSafeCheck = 790;
+ constexpr int QueenSafeCheck = 772;
+ constexpr int RookSafeCheck = 1084;
+ constexpr int BishopSafeCheck = 645;
+ constexpr int KnightSafeCheck = 792;
#define S(mg, eg) make_score(mg, eg)
// MobilityBonus[PieceType-2][attacked] contains bonuses for middle and end game,
// indexed by piece type and number of attacked squares in the mobility area.
constexpr Score MobilityBonus[][32] = {
- { S(-62,-81), S(-53,-56), S(-12,-30), S( -4,-14), S( 3, 8), S( 13, 15), // Knights
+ { S(-62,-81), S(-53,-56), S(-12,-30), S( -4,-14), S( 3, 8), S( 13, 15), // Knight
S( 22, 23), S( 28, 27), S( 33, 33) },
- { S(-48,-59), S(-20,-23), S( 16, -3), S( 26, 13), S( 38, 24), S( 51, 42), // Bishops
+ { S(-48,-59), S(-20,-23), S( 16, -3), S( 26, 13), S( 38, 24), S( 51, 42), // Bishop
S( 55, 54), S( 63, 57), S( 63, 65), S( 68, 73), S( 81, 78), S( 81, 86),
S( 91, 88), S( 98, 97) },
- { S(-58,-76), S(-27,-18), S(-15, 28), S(-10, 55), S( -5, 69), S( -2, 82), // Rooks
- S( 9,112), S( 16,118), S( 30,132), S( 29,142), S( 32,155), S( 38,165),
- S( 46,166), S( 48,169), S( 58,171) },
- { S(-39,-36), S(-21,-15), S( 3, 8), S( 3, 18), S( 14, 34), S( 22, 54), // Queens
- S( 28, 61), S( 41, 73), S( 43, 79), S( 48, 92), S( 56, 94), S( 60,104),
- S( 60,113), S( 66,120), S( 67,123), S( 70,126), S( 71,133), S( 73,136),
- S( 79,140), S( 88,143), S( 88,148), S( 99,166), S(102,170), S(102,175),
- S(106,184), S(109,191), S(113,206), S(116,212) }
+ { S(-60,-78), S(-20,-17), S( 2, 23), S( 3, 39), S( 3, 70), S( 11, 99), // Rook
+ S( 22,103), S( 31,121), S( 40,134), S( 40,139), S( 41,158), S( 48,164),
+ S( 57,168), S( 57,169), S( 62,172) },
+ { S(-34,-36), S(-15,-21), S(-10, -1), S(-10, 22), S( 20, 41), S( 23, 56), // Queen
+ S( 23, 59), S( 35, 75), S( 38, 78), S( 53, 96), S( 64, 96), S( 65,100),
+ S( 65,121), S( 66,127), S( 67,131), S( 67,133), S( 72,136), S( 72,141),
+ S( 77,147), S( 79,150), S( 93,151), S(108,168), S(108,168), S(108,171),
+ S(110,182), S(114,182), S(114,192), S(116,219) }
};
// RookOnFile[semiopen/open] contains bonuses for each rook when there is
// no (friendly) pawn on the rook file.
- constexpr Score RookOnFile[] = { S(18, 7), S(44, 20) };
+ constexpr Score RookOnFile[] = { S(19, 7), S(48, 29) };
// ThreatByMinor/ByRook[attacked PieceType] contains bonuses according to
// which piece type attacks which one. Attacks on lesser pieces which are
// pawn-defended are not considered.
constexpr Score ThreatByMinor[PIECE_TYPE_NB] = {
- S(0, 0), S(0, 31), S(39, 42), S(57, 44), S(68, 112), S(62, 120)
+ S(0, 0), S(5, 32), S(57, 41), S(77, 56), S(88, 119), S(79, 161)
};
constexpr Score ThreatByRook[PIECE_TYPE_NB] = {
- S(0, 0), S(0, 24), S(38, 71), S(38, 61), S(0, 38), S(51, 38)
+ S(0, 0), S(3, 46), S(37, 68), S(42, 60), S(0, 38), S(58, 41)
};
// PassedRank[Rank] contains a bonus according to the rank of a passed pawn
};
// Assorted bonuses and penalties
- constexpr Score BishopPawns = S( 3, 7);
- constexpr Score CorneredBishop = S( 50, 50);
- constexpr Score FlankAttacks = S( 8, 0);
- constexpr Score Hanging = S( 69, 36);
- constexpr Score KingProtector = S( 7, 8);
- constexpr Score KnightOnQueen = S( 16, 12);
- constexpr Score LongDiagonalBishop = S( 45, 0);
- constexpr Score MinorBehindPawn = S( 18, 3);
- constexpr Score Outpost = S( 18, 6);
- constexpr Score PassedFile = S( 11, 8);
- constexpr Score PawnlessFlank = S( 17, 95);
- constexpr Score RestrictedPiece = S( 7, 7);
- constexpr Score RookOnPawn = S( 10, 32);
- constexpr Score RookOnQueenFile = S( 11, 4);
- constexpr Score SliderOnQueen = S( 59, 18);
- constexpr Score ThreatByKing = S( 24, 89);
- constexpr Score ThreatByPawnPush = S( 48, 39);
- constexpr Score ThreatByRank = S( 13, 0);
- constexpr Score ThreatBySafePawn = S(173, 94);
- constexpr Score TrappedRook = S( 47, 4);
- constexpr Score WeakQueen = S( 49, 15);
+ constexpr Score BishopPawns = S( 3, 7);
+ constexpr Score BishopXRayPawns = S( 4, 5);
+ constexpr Score CorneredBishop = S( 50, 50);
+ constexpr Score FlankAttacks = S( 8, 0);
+ constexpr Score Hanging = S( 69, 36);
+ constexpr Score BishopKingProtector = S( 6, 9);
+ constexpr Score KnightKingProtector = S( 8, 9);
+ constexpr Score KnightOnQueen = S( 16, 11);
+ constexpr Score LongDiagonalBishop = S( 45, 0);
+ constexpr Score MinorBehindPawn = S( 18, 3);
+ constexpr Score KnightOutpost = S( 56, 36);
+ constexpr Score BishopOutpost = S( 30, 23);
+ constexpr Score ReachableOutpost = S( 31, 22);
+ constexpr Score PassedFile = S( 11, 8);
+ constexpr Score PawnlessFlank = S( 17, 95);
+ constexpr Score RestrictedPiece = S( 7, 7);
+ constexpr Score RookOnQueenFile = S( 5, 9);
+ constexpr Score SliderOnQueen = S( 59, 18);
+ constexpr Score ThreatByKing = S( 24, 89);
+ constexpr Score ThreatByPawnPush = S( 48, 39);
+ constexpr Score ThreatBySafePawn = S(173, 94);
+ constexpr Score TrappedRook = S( 55, 13);
+ constexpr Score WeakQueen = S( 51, 14);
+ constexpr Score WeakQueenProtection = S( 15, 0);
#undef S
template<Tracing T> template<Color Us>
void Evaluation<T>::initialize() {
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
- constexpr Direction Up = (Us == WHITE ? NORTH : SOUTH);
- constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH);
+ constexpr Color Them = ~Us;
+ constexpr Direction Up = pawn_push(Us);
+ constexpr Direction Down = -Up;
constexpr Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB : Rank7BB | Rank6BB);
const Square ksq = pos.square<KING>(Us);
// Find our pawns that are blocked or on the first two ranks
Bitboard b = pos.pieces(Us, PAWN) & (shift<Down>(pos.pieces()) | LowRanks);
- // Squares occupied by those pawns, by our king or queen or controlled by
- // enemy pawns are excluded from the mobility area.
- mobilityArea[Us] = ~(b | pos.pieces(Us, KING, QUEEN) | pe->pawn_attacks(Them));
+ // Squares occupied by those pawns, by our king or queen, by blockers to attacks on our king
+ // or controlled by enemy pawns are excluded from the mobility area.
+ mobilityArea[Us] = ~(b | pos.pieces(Us, KING, QUEEN) | pos.blockers_for_king(Us) | pe->pawn_attacks(Them));
// Initialize attackedBy[] for king and pawns
attackedBy[Us][KING] = pos.attacks_from<KING>(ksq);
attackedBy2[Us] = dblAttackByPawn | (attackedBy[Us][KING] & attackedBy[Us][PAWN]);
// Init our king safety tables
- kingRing[Us] = attackedBy[Us][KING];
- if (relative_rank(Us, ksq) == RANK_1)
- kingRing[Us] |= shift<Up>(kingRing[Us]);
-
- if (file_of(ksq) == FILE_H)
- kingRing[Us] |= shift<WEST>(kingRing[Us]);
-
- else if (file_of(ksq) == FILE_A)
- kingRing[Us] |= shift<EAST>(kingRing[Us]);
+ Square s = make_square(Utility::clamp(file_of(ksq), FILE_B, FILE_G),
+ Utility::clamp(rank_of(ksq), RANK_2, RANK_7));
+ kingRing[Us] = PseudoAttacks[KING][s] | s;
kingAttackersCount[Them] = popcount(kingRing[Us] & pe->pawn_attacks(Them));
kingAttacksCount[Them] = kingAttackersWeight[Them] = 0;
template<Tracing T> template<Color Us, PieceType Pt>
Score Evaluation<T>::pieces() {
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
- constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH);
+ constexpr Color Them = ~Us;
+ constexpr Direction Down = -pawn_push(Us);
constexpr Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB
: Rank5BB | Rank4BB | Rank3BB);
const Square* pl = pos.squares<Pt>(Us);
// Bonus if piece is on an outpost square or can reach one
bb = OutpostRanks & attackedBy[Us][PAWN] & ~pe->pawn_attacks_span(Them);
if (bb & s)
- score += Outpost * (Pt == KNIGHT ? 4 : 2);
-
- else if (bb & b & ~pos.pieces(Us))
- score += Outpost * (Pt == KNIGHT ? 2 : 1);
+ score += (Pt == KNIGHT) ? KnightOutpost : BishopOutpost;
+ else if (Pt == KNIGHT && bb & b & ~pos.pieces(Us))
+ score += ReachableOutpost;
- // Knight and Bishop bonus for being right behind a pawn
+ // Bonus for a knight or bishop shielded by pawn
if (shift<Down>(pos.pieces(PAWN)) & s)
score += MinorBehindPawn;
// Penalty if the piece is far from the king
- score -= KingProtector * distance(s, pos.square<KING>(Us));
+ score -= (Pt == KNIGHT ? KnightKingProtector
+ : BishopKingProtector) * distance(pos.square<KING>(Us), s);
if (Pt == BISHOP)
{
// Penalty according to number of pawns on the same color square as the
- // bishop, bigger when the center files are blocked with pawns.
+ // bishop, bigger when the center files are blocked with pawns and smaller
+ // when the bishop is outside the pawn chain.
Bitboard blocked = pos.pieces(Us, PAWN) & shift<Down>(pos.pieces());
score -= BishopPawns * pos.pawns_on_same_color_squares(Us, s)
- * (1 + popcount(blocked & CenterFiles));
+ * (!(attackedBy[Us][PAWN] & s) + popcount(blocked & CenterFiles));
+
+ // Penalty for all enemy pawns x-rayed
+ score -= BishopXRayPawns * popcount(PseudoAttacks[BISHOP][s] & pos.pieces(Them, PAWN));
// Bonus for bishop on a long diagonal which can "see" both center squares
if (more_than_one(attacks_bb<BISHOP>(s, pos.pieces(PAWN)) & Center))
score += LongDiagonalBishop;
- }
- // An important Chess960 pattern: A cornered bishop blocked by a friendly
- // pawn diagonally in front of it is a very serious problem, especially
- // when that pawn is also blocked.
- if ( Pt == BISHOP
- && pos.is_chess960()
- && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
- {
- Direction d = pawn_push(Us) + (file_of(s) == FILE_A ? EAST : WEST);
- if (pos.piece_on(s + d) == make_piece(Us, PAWN))
- score -= !pos.empty(s + d + pawn_push(Us)) ? CorneredBishop * 4
- : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? CorneredBishop * 2
- : CorneredBishop;
+ // An important Chess960 pattern: a cornered bishop blocked by a friendly
+ // pawn diagonally in front of it is a very serious problem, especially
+ // when that pawn is also blocked.
+ if ( pos.is_chess960()
+ && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
+ {
+ Direction d = pawn_push(Us) + (file_of(s) == FILE_A ? EAST : WEST);
+ if (pos.piece_on(s + d) == make_piece(Us, PAWN))
+ score -= !pos.empty(s + d + pawn_push(Us)) ? CorneredBishop * 4
+ : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? CorneredBishop * 2
+ : CorneredBishop;
+ }
}
}
if (Pt == ROOK)
{
- // Bonus for aligning rook with enemy pawns on the same rank/file
- if (relative_rank(Us, s) >= RANK_5)
- score += RookOnPawn * popcount(pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]);
-
// Bonus for rook on the same file as a queen
if (file_bb(s) & pos.pieces(QUEEN))
score += RookOnQueenFile;
template<Tracing T> template<Color Us>
Score Evaluation<T>::king() const {
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Color Them = ~Us;
constexpr Bitboard Camp = (Us == WHITE ? AllSquares ^ Rank6BB ^ Rank7BB ^ Rank8BB
: AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB);
- Bitboard weak, b1, b2, safe, unsafeChecks = 0;
+ Bitboard weak, b1, b2, b3, safe, unsafeChecks = 0;
Bitboard rookChecks, queenChecks, bishopChecks, knightChecks;
int kingDanger = 0;
const Square ksq = pos.square<KING>(Us);
// Enemy rooks checks
rookChecks = b1 & safe & attackedBy[Them][ROOK];
-
if (rookChecks)
- kingDanger += RookSafeCheck;
+ kingDanger += more_than_one(rookChecks) ? RookSafeCheck * 175/100
+ : RookSafeCheck;
else
unsafeChecks |= b1 & attackedBy[Them][ROOK];
& safe
& ~attackedBy[Us][QUEEN]
& ~rookChecks;
-
if (queenChecks)
- kingDanger += QueenSafeCheck;
+ kingDanger += more_than_one(queenChecks) ? QueenSafeCheck * 145/100
+ : QueenSafeCheck;
// Enemy bishops checks: we count them only if they are from squares from
// which we can't give a queen check, because queen checks are more valuable.
& attackedBy[Them][BISHOP]
& safe
& ~queenChecks;
-
if (bishopChecks)
- kingDanger += BishopSafeCheck;
+ kingDanger += more_than_one(bishopChecks) ? BishopSafeCheck * 3/2
+ : BishopSafeCheck;
else
unsafeChecks |= b2 & attackedBy[Them][BISHOP];
// Enemy knights checks
knightChecks = pos.attacks_from<KNIGHT>(ksq) & attackedBy[Them][KNIGHT];
-
if (knightChecks & safe)
- kingDanger += KnightSafeCheck;
+ kingDanger += more_than_one(knightChecks & safe) ? KnightSafeCheck * 162/100
+ : KnightSafeCheck;
else
unsafeChecks |= knightChecks;
- // Find the squares that opponent attacks in our king flank, and the squares
- // which are attacked twice in that flank.
+ // Find the squares that opponent attacks in our king flank, the squares
+ // which they attack twice in that flank, and the squares that we defend.
b1 = attackedBy[Them][ALL_PIECES] & KingFlank[file_of(ksq)] & Camp;
b2 = b1 & attackedBy2[Them];
+ b3 = attackedBy[Us][ALL_PIECES] & KingFlank[file_of(ksq)] & Camp;
- int kingFlankAttacks = popcount(b1) + popcount(b2);
+ int kingFlankAttack = popcount(b1) + popcount(b2);
+ int kingFlankDefense = popcount(b3);
kingDanger += kingAttackersCount[Them] * kingAttackersWeight[Them]
- + 69 * kingAttacksCount[Them]
+ 185 * popcount(kingRing[Us] & weak)
- - 100 * bool(attackedBy[Us][KNIGHT] & attackedBy[Us][KING])
- - 35 * bool(attackedBy[Us][BISHOP] & attackedBy[Us][KING])
+ 148 * popcount(unsafeChecks)
+ 98 * popcount(pos.blockers_for_king(Us))
+ + 69 * kingAttacksCount[Them]
+ + 3 * kingFlankAttack * kingFlankAttack / 8
+ + mg_value(mobility[Them] - mobility[Us])
- 873 * !pos.count<QUEEN>(Them)
+ - 100 * bool(attackedBy[Us][KNIGHT] & attackedBy[Us][KING])
- 6 * mg_value(score) / 8
- + mg_value(mobility[Them] - mobility[Us])
- + 5 * kingFlankAttacks * kingFlankAttacks / 16
- - 7;
+ - 4 * kingFlankDefense
+ + 37;
// Transform the kingDanger units into a Score, and subtract it from the evaluation
if (kingDanger > 100)
score -= PawnlessFlank;
// Penalty if king flank is under attack, potentially moving toward the king
- score -= FlankAttacks * kingFlankAttacks;
+ score -= FlankAttacks * kingFlankAttack;
if (T)
Trace::add(KING, Us, score);
template<Tracing T> template<Color Us>
Score Evaluation<T>::threats() const {
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
- constexpr Direction Up = (Us == WHITE ? NORTH : SOUTH);
+ constexpr Color Them = ~Us;
+ constexpr Direction Up = pawn_push(Us);
constexpr Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
Bitboard b, weak, defended, nonPawnEnemies, stronglyProtected, safe;
{
b = (defended | weak) & (attackedBy[Us][KNIGHT] | attackedBy[Us][BISHOP]);
while (b)
- {
- Square s = pop_lsb(&b);
- score += ThreatByMinor[type_of(pos.piece_on(s))];
- if (type_of(pos.piece_on(s)) != PAWN)
- score += ThreatByRank * (int)relative_rank(Them, s);
- }
+ score += ThreatByMinor[type_of(pos.piece_on(pop_lsb(&b)))];
b = weak & attackedBy[Us][ROOK];
while (b)
- {
- Square s = pop_lsb(&b);
- score += ThreatByRook[type_of(pos.piece_on(s))];
- if (type_of(pos.piece_on(s)) != PAWN)
- score += ThreatByRank * (int)relative_rank(Them, s);
- }
+ score += ThreatByRook[type_of(pos.piece_on(pop_lsb(&b)))];
if (weak & attackedBy[Us][KING])
score += ThreatByKing;
b = ~attackedBy[Them][ALL_PIECES]
| (nonPawnEnemies & attackedBy2[Us]);
score += Hanging * popcount(weak & b);
+
+ // Additional bonus if weak piece is only protected by a queen
+ score += WeakQueenProtection * popcount(weak & attackedBy[Them][QUEEN]);
}
// Bonus for restricting their piece moves
b = attackedBy[Them][ALL_PIECES]
& ~stronglyProtected
& attackedBy[Us][ALL_PIECES];
-
score += RestrictedPiece * popcount(b);
// Protected or unattacked squares
template<Tracing T> template<Color Us>
Score Evaluation<T>::passed() const {
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
- constexpr Direction Up = (Us == WHITE ? NORTH : SOUTH);
+ constexpr Color Them = ~Us;
+ constexpr Direction Up = pawn_push(Us);
+ constexpr Direction Down = -Up;
auto king_proximity = [&](Color c, Square s) {
return std::min(distance(pos.square<KING>(c), s), 5);
};
- Bitboard b, bb, squaresToQueen, unsafeSquares;
+ Bitboard b, bb, squaresToQueen, unsafeSquares, blockedPassers, helpers;
Score score = SCORE_ZERO;
b = pe->passed_pawns(Us);
+ blockedPassers = b & shift<Down>(pos.pieces(Them, PAWN));
+ if (blockedPassers)
+ {
+ helpers = shift<Up>(pos.pieces(Us, PAWN))
+ & ~pos.pieces(Them)
+ & (~attackedBy2[Them] | attackedBy[Us][ALL_PIECES]);
+
+ // Remove blocked candidate passers that don't have help to pass
+ b &= ~blockedPassers
+ | shift<WEST>(helpers)
+ | shift<EAST>(helpers);
+ }
+
while (b)
{
Square s = pop_lsb(&b);
assert(!(pos.pieces(Them, PAWN) & forward_file_bb(Us, s + Up)));
int r = relative_rank(Us, s);
- File f = file_of(s);
Score bonus = PassedRank[r];
Square blockSq = s + Up;
// Adjust bonus based on the king's proximity
- bonus += make_score(0, ( king_proximity(Them, blockSq) * 5
- - king_proximity(Us, blockSq) * 2) * w);
+ bonus += make_score(0, ( (king_proximity(Them, blockSq) * 19) / 4
+ - king_proximity(Us, blockSq) * 2) * w);
// If blockSq is not the queening square then consider also a second push
if (r != RANK_7)
}
} // r > RANK_3
- // Scale down bonus for candidate passers which need more than one
- // pawn push to become passed, or have a pawn in front of them.
- if ( !pos.pawn_passed(Us, s + Up)
- || (pos.pieces(PAWN) & (s + Up)))
- bonus = bonus / 2;
-
- score += bonus - PassedFile * std::min(f, ~f);
+ score += bonus - PassedFile * edge_distance(file_of(s));
}
if (T)
if (pos.non_pawn_material() < SpaceThreshold)
return SCORE_ZERO;
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
- constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH);
+ constexpr Color Them = ~Us;
+ constexpr Direction Down = -pawn_push(Us);
constexpr Bitboard SpaceMask =
Us == WHITE ? CenterFiles & (Rank2BB | Rank3BB | Rank4BB)
: CenterFiles & (Rank7BB | Rank6BB | Rank5BB);
behind |= shift<Down+Down>(behind);
int bonus = popcount(safe) + popcount(behind & safe & ~attackedBy[Them][ALL_PIECES]);
- int weight = pos.count<ALL_PIECES>(Us) - 1;
+ int weight = pos.count<ALL_PIECES>(Us) - 3 + std::min(pe->blocked_count(), 9);
Score score = make_score(bonus * weight * weight / 16, 0);
if (T)
template<Tracing T>
Score Evaluation<T>::initiative(Score score) const {
- Value mg = mg_value(score);
- Value eg = eg_value(score);
-
int outflanking = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
- distance<Rank>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
bool pawnsOnBothFlanks = (pos.pieces(PAWN) & QueenSide)
&& (pos.pieces(PAWN) & KingSide);
- bool almostUnwinnable = !pe->passed_count()
- && outflanking < 0
+ bool almostUnwinnable = outflanking < 0
&& !pawnsOnBothFlanks;
+ bool infiltration = rank_of(pos.square<KING>(WHITE)) > RANK_4
+ || rank_of(pos.square<KING>(BLACK)) < RANK_5;
+
// Compute the initiative bonus for the attacking side
int complexity = 9 * pe->passed_count()
- + 1
1 * pos.count<PAWN>()
+ + 1
2 * pos.count<PAWN>()
+ 9 * outflanking
- + 18 * pawnsOnBothFlanks
- + 49 * !pos.non_pawn_material()
- - 36 * almostUnwinnable
- -103 ;
+ + 21 * pawnsOnBothFlanks
+ + 24 * infiltration
+ + 51 * !pos.non_pawn_material()
+ - 43 * almostUnwinnable
+ - 2 * pos.rule50_count()
+ -110 ;
+
+ Value mg = mg_value(score);
+ Value eg = eg_value(score);
// Now apply the bonus: note that we find the attacking side by extracting the
// sign of the midgame or endgame values, and that we carefully cap the bonus
// so that the midgame and endgame scores do not change sign after the bonus.
- int u = ((mg > 0) - (mg < 0)) * std::max(std::min(complexity + 50, 0), -abs(mg));
+ int u = ((mg > 0) - (mg < 0)) * Utility::clamp(complexity + 50, -abs(mg), 0);
int v = ((eg > 0) - (eg < 0)) * std::max(complexity, -abs(eg));
if (T)
// If scale is not already specific, scale down the endgame via general heuristics
if (sf == SCALE_FACTOR_NORMAL)
{
- if ( pos.opposite_bishops()
- && pos.non_pawn_material() == 2 * BishopValueMg)
- sf = 16 + 4 * pe->passed_count();
+ if (pos.opposite_bishops())
+ {
+ if ( pos.non_pawn_material(WHITE) == BishopValueMg
+ && pos.non_pawn_material(BLACK) == BishopValueMg)
+ sf = 18 + 4 * popcount(pe->passed_pawns(strongSide));
+ else
+ sf = 22 + 3 * pos.count<ALL_PIECES>(strongSide);
+ }
else
- sf = std::min(sf, 36 + (pos.opposite_bishops() ? 2 : 7) * pos.count<PAWN>(strongSide));
-
- sf = std::max(0, sf - (pos.rule50_count() - 12) / 4 );
+ sf = std::min(sf, 36 + 7 * pos.count<PAWN>(strongSide));
}
return ScaleFactor(sf);
initialize<WHITE>();
initialize<BLACK>();
- // Pieces should be evaluated first (populate attack tables)
+ // Pieces evaluated first (also populates attackedBy, attackedBy2).
+ // Note that the order of evaluation of the terms is left unspecified
score += pieces<WHITE, KNIGHT>() - pieces<BLACK, KNIGHT>()
+ pieces<WHITE, BISHOP>() - pieces<BLACK, BISHOP>()
+ pieces<WHITE, ROOK >() - pieces<BLACK, ROOK >()
score += mobility[WHITE] - mobility[BLACK];
+ // More complex interactions that require fully populated attack bitboards
score += king< WHITE>() - king< BLACK>()
+ threats<WHITE>() - threats<BLACK>()
+ passed< WHITE>() - passed< BLACK>()
Trace::add(TOTAL, score);
}
- return (pos.side_to_move() == WHITE ? v : -v) // Side to move point of view
- + Eval::Tempo;
+ // Side to move point of view
+ return (pos.side_to_move() == WHITE ? v : -v) + Tempo;
}
} // namespace
std::string Eval::trace(const Position& pos) {
+ if (pos.checkers())
+ return "Total evaluation: none (in check)";
+
std::memset(scores, 0, sizeof(scores));
pos.this_thread()->contempt = SCORE_ZERO; // Reset any dynamic contempt
projects / stockfish / blobdiff