Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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 LazyThreshold1 = Value(1400);
- constexpr Value LazyThreshold2 = Value(1300);
- constexpr Value SpaceThreshold = Value(12222);
- constexpr Value NNUEThreshold1 = Value(550);
- constexpr Value NNUEThreshold2 = Value(150);
+ constexpr Value LazyThreshold1 = Value(1565);
+ constexpr Value LazyThreshold2 = Value(1102);
+ constexpr Value SpaceThreshold = Value(11551);
+ constexpr Value NNUEThreshold1 = Value(682);
+ constexpr Value NNUEThreshold2 = Value(176);
// KingAttackWeights[PieceType] contains king attack weights by piece type
constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 81, 52, 44, 10 };
// KingAttackWeights[PieceType] contains king attack weights by piece type
constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 81, 52, 44, 10 };
{ S(-47,-59), S(-20,-25), S( 14, -8), S( 29, 12), S( 39, 21), S( 53, 40), // Bishop
S( 53, 56), S( 60, 58), S( 62, 65), S( 69, 72), S( 78, 78), S( 83, 87),
S( 91, 88), S( 96, 98) },
{ S(-47,-59), S(-20,-25), S( 14, -8), S( 29, 12), S( 39, 21), S( 53, 40), // Bishop
S( 53, 56), S( 60, 58), S( 62, 65), S( 69, 72), S( 78, 78), S( 83, 87),
S( 91, 88), S( 96, 98) },
- { S(-61,-82), S(-20,-17), S( 2, 23) ,S( 3, 40), S( 4, 72), S( 11,100), // Rook
- S( 22,104), S( 31,120), S( 39,134), S(40 ,138), S( 41,158), S( 47,163),
- S( 59,168), S( 60,169), S( 64,173) },
+ { S(-60,-82), S(-24,-15), S( 0, 17) ,S( 3, 43), S( 4, 72), S( 14,100), // Rook
+ S( 20,102), S( 30,122), S( 41,133), S(41 ,139), S( 41,153), S( 45,160),
+ S( 57,165), S( 58,170), S( 67,175) },
{ S(-29,-49), S(-16,-29), S( -8, -8), S( -8, 17), S( 18, 39), S( 25, 54), // Queen
S( 23, 59), S( 37, 73), S( 41, 76), S( 54, 95), S( 65, 95) ,S( 68,101),
S( 69,124), S( 70,128), S( 70,132), S( 70,133) ,S( 71,136), S( 72,140),
{ S(-29,-49), S(-16,-29), S( -8, -8), S( -8, 17), S( 18, 39), S( 25, 54), // Queen
S( 23, 59), S( 37, 73), S( 41, 76), S( 54, 95), S( 65, 95) ,S( 68,101),
S( 69,124), S( 70,128), S( 70,132), S( 70,133) ,S( 71,136), S( 72,140),
S(112,178), S(114,185), S(114,187), S(119,221) }
};
S(112,178), S(114,185), S(114,187), S(119,221) }
};
+ // BishopPawns[distance from edge] contains a file-dependent penalty for pawns on
+ // squares of the same color as our bishop.
+ constexpr Score BishopPawns[int(FILE_NB) / 2] = {
+ S(3, 8), S(3, 9), S(1, 8), S(3, 7)
+ };
+
// KingProtector[knight/bishop] contains penalty for each distance unit to own king
constexpr Score KingProtector[] = { S(8, 9), S(6, 9) };
// KingProtector[knight/bishop] contains penalty for each distance unit to own king
constexpr Score KingProtector[] = { S(8, 9), S(6, 9) };
// PassedRank[Rank] contains a bonus according to the rank of a passed pawn
constexpr Score PassedRank[RANK_NB] = {
// PassedRank[Rank] contains a bonus according to the rank of a passed pawn
constexpr Score PassedRank[RANK_NB] = {
- S(0, 0), S(9, 28), S(15, 31), S(17, 39), S(64, 70), S(171, 177), S(277, 260)
+ S(0, 0), S(7, 27), S(16, 32), S(17, 40), S(64, 71), S(170, 174), S(278, 262)
- // RookOnFile[semiopen/open] contains bonuses for each rook when there is
- // no (friendly) pawn on the rook file.
- constexpr Score RookOnFile[] = { S(19, 7), S(48, 27) };
+ constexpr Score RookOnClosedFile = S(10, 5);
+ constexpr Score RookOnOpenFile[] = { S(19, 6), S(47, 26) };
// ThreatByMinor/ByRook[attacked PieceType] contains bonuses according to
// which piece type attacks which one. Attacks on lesser pieces which are
// ThreatByMinor/ByRook[attacked PieceType] contains bonuses according to
// which piece type attacks which one. Attacks on lesser pieces which are
// Assorted bonuses and penalties
constexpr Score BadOutpost = S( -7, 36);
constexpr Score BishopOnKingRing = S( 24, 0);
// Assorted bonuses and penalties
constexpr Score BadOutpost = S( -7, 36);
constexpr Score BishopOnKingRing = S( 24, 0);
constexpr Score BishopXRayPawns = S( 4, 5);
constexpr Score CorneredBishop = S( 50, 50);
constexpr Score FlankAttacks = S( 8, 0);
constexpr Score BishopXRayPawns = S( 4, 5);
constexpr Score CorneredBishop = S( 50, 50);
constexpr Score FlankAttacks = S( 8, 0);
constexpr Direction Down = -pawn_push(Us);
constexpr Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB
: Rank5BB | Rank4BB | Rank3BB);
constexpr Direction Down = -pawn_push(Us);
constexpr Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB
: Rank5BB | Rank4BB | Rank3BB);
// Find attacked squares, including x-ray attacks for bishops and rooks
b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(QUEEN))
: Pt == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(QUEEN) ^ pos.pieces(Us, ROOK))
// Find attacked squares, including x-ray attacks for bishops and rooks
b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(QUEEN))
: Pt == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(QUEEN) ^ pos.pieces(Us, ROOK))
// when the bishop is outside the pawn chain.
Bitboard blocked = pos.pieces(Us, PAWN) & shift<Down>(pos.pieces());
// when the bishop is outside the pawn chain.
Bitboard blocked = pos.pieces(Us, PAWN) & shift<Down>(pos.pieces());
* (!(attackedBy[Us][PAWN] & s) + popcount(blocked & CenterFiles));
// Penalty for all enemy pawns x-rayed
* (!(attackedBy[Us][PAWN] & s) + popcount(blocked & CenterFiles));
// Penalty for all enemy pawns x-rayed
- File kf = file_of(pos.square<KING>(Us));
- if ((kf < FILE_E) == (file_of(s) < kf))
- score -= TrappedRook * (1 + !pos.castling_rights(Us));
+ score += RookOnOpenFile[pos.is_on_semiopen_file(Them, s)];
+ }
+ else
+ {
+ // If our pawn on this file is blocked, increase penalty
+ if ( pos.pieces(Us, PAWN)
+ & shift<Down>(pos.pieces())
+ & file_bb(s))
+ {
+ score -= RookOnClosedFile;
+ }
+
+ // Penalty when trapped by the king, even more if the king cannot castle
+ if (mob <= 3)
+ {
+ File kf = file_of(pos.square<KING>(Us));
+ if ((kf < FILE_E) == (file_of(s) < kf))
+ score -= TrappedRook * (1 + !pos.castling_rights(Us));
+ }
- kingDanger += kingAttackersCount[Them] * kingAttackersWeight[Them]
- + 185 * popcount(kingRing[Us] & weak)
- + 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
- - 4 * kingFlankDefense
- + 37;
+ kingDanger += kingAttackersCount[Them] * kingAttackersWeight[Them] // (~10 Elo)
+ + 183 * popcount(kingRing[Us] & weak) // (~15 Elo)
+ + 148 * popcount(unsafeChecks) // (~4 Elo)
+ + 98 * popcount(pos.blockers_for_king(Us)) // (~2 Elo)
+ + 69 * kingAttacksCount[Them] // (~0.5 Elo)
+ + 3 * kingFlankAttack * kingFlankAttack / 8 // (~0.5 Elo)
+ + mg_value(mobility[Them] - mobility[Us]) // (~0.5 Elo)
+ - 873 * !pos.count<QUEEN>(Them) // (~24 Elo)
+ - 100 * bool(attackedBy[Us][KNIGHT] & attackedBy[Us][KING]) // (~5 Elo)
+ - 6 * mg_value(score) / 8 // (~8 Elo)
+ - 4 * kingFlankDefense // (~5 Elo)
+ + 37; // (~0.5 Elo)
bb = forward_file_bb(Them, s) & pos.pieces(ROOK, QUEEN);
if (!(pos.pieces(Them) & bb))
bb = forward_file_bb(Them, s) & pos.pieces(ROOK, QUEEN);
if (!(pos.pieces(Them) & bb))
- // If there are no enemy attacks on passed pawn span, assign a big bonus.
+ // If there are no enemy pieces or attacks on passed pawn span, assign a big bonus.
+ // Or if there is some, but they are all attacked by our pawns, assign a bit smaller bonus.
// Otherwise assign a smaller bonus if the path to queen is not attacked
// and even smaller bonus if it is attacked but block square is not.
// Otherwise assign a smaller bonus if the path to queen is not attacked
// and even smaller bonus if it is attacked but block square is not.
- int k = !unsafeSquares ? 35 :
- !(unsafeSquares & squaresToQueen) ? 20 :
- !(unsafeSquares & blockSq) ? 9 :
+ int k = !unsafeSquares ? 36 :
+ !(unsafeSquares & ~attackedBy[Us][PAWN]) ? 30 :
+ !(unsafeSquares & squaresToQueen) ? 17 :
+ !(unsafeSquares & blockSq) ? 7 :
int bonus = popcount(safe) + popcount(behind & safe & ~attackedBy[Them][ALL_PIECES]);
int weight = pos.count<ALL_PIECES>(Us) - 3 + std::min(pe->blocked_count(), 9);
Score score = make_score(bonus * weight * weight / 16, 0);
int bonus = popcount(safe) + popcount(behind & safe & ~attackedBy[Them][ALL_PIECES]);
int weight = pos.count<ALL_PIECES>(Us) - 3 + std::min(pe->blocked_count(), 9);
Score score = make_score(bonus * weight * weight / 16, 0);
Value Evaluation<T>::winnable(Score score) const {
int outflanking = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
Value Evaluation<T>::winnable(Score score) const {
int outflanking = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
if ( pos.non_pawn_material(WHITE) == BishopValueMg
&& pos.non_pawn_material(BLACK) == BishopValueMg)
sf = 18 + 4 * popcount(pe->passed_pawns(strongSide));
if ( pos.non_pawn_material(WHITE) == BishopValueMg
&& pos.non_pawn_material(BLACK) == BishopValueMg)
sf = 18 + 4 * popcount(pe->passed_pawns(strongSide));
else if ( pos.non_pawn_material(WHITE) == RookValueMg
&& pos.non_pawn_material(BLACK) == RookValueMg
&& pos.count<PAWN>(strongSide) - pos.count<PAWN>(~strongSide) <= 1
&& bool(KingSide & pos.pieces(strongSide, PAWN)) != bool(QueenSide & pos.pieces(strongSide, PAWN))
&& (attacks_bb<KING>(pos.square<KING>(~strongSide)) & pos.pieces(~strongSide, PAWN)))
sf = 36;
else if ( pos.non_pawn_material(WHITE) == RookValueMg
&& pos.non_pawn_material(BLACK) == RookValueMg
&& pos.count<PAWN>(strongSide) - pos.count<PAWN>(~strongSide) <= 1
&& bool(KingSide & pos.pieces(strongSide, PAWN)) != bool(QueenSide & pos.pieces(strongSide, PAWN))
&& (attacks_bb<KING>(pos.square<KING>(~strongSide)) & pos.pieces(~strongSide, PAWN)))
sf = 36;
else if (pos.count<QUEEN>() == 1)
sf = 37 + 3 * (pos.count<QUEEN>(WHITE) == 1 ? pos.count<BISHOP>(BLACK) + pos.count<KNIGHT>(BLACK)
: pos.count<BISHOP>(WHITE) + pos.count<KNIGHT>(WHITE));
else if (pos.count<QUEEN>() == 1)
sf = 37 + 3 * (pos.count<QUEEN>(WHITE) == 1 ? pos.count<BISHOP>(BLACK) + pos.count<KNIGHT>(BLACK)
: pos.count<BISHOP>(WHITE) + pos.count<KNIGHT>(WHITE));
- sf = std::min(sf, 36 + 7 * pos.count<PAWN>(strongSide));
+ sf = std::min(sf, 36 + 7 * pos.count<PAWN>(strongSide)) - 4 * !pawnsOnBothFlanks;
+
+ // Reduce scale factor in case of pawns being on a single flank
+ sf -= 4 * !pawnsOnBothFlanks;
{
// Scale and shift NNUE for compatibility with search and classical evaluation
auto adjusted_NNUE = [&](){
{
// Scale and shift NNUE for compatibility with search and classical evaluation
auto adjusted_NNUE = [&](){
- int mat = pos.non_pawn_material() + PieceValue[MG][PAWN] * pos.count<PAWN>();
- return NNUE::evaluate(pos) * (720 + mat / 32) / 1024 + Tempo;
+ int mat = pos.non_pawn_material() + PawnValueMg * pos.count<PAWN>();
+ return NNUE::evaluate(pos) * (679 + mat / 32) / 1024 + Tempo;
bool largePsq = psq * 16 > (NNUEThreshold1 + pos.non_pawn_material() / 64) * r50;
bool classical = largePsq || (psq > PawnValueMg / 4 && !(pos.this_thread()->nodes & 0xB));
bool largePsq = psq * 16 > (NNUEThreshold1 + pos.non_pawn_material() / 64) * r50;
bool classical = largePsq || (psq > PawnValueMg / 4 && !(pos.this_thread()->nodes & 0xB));
- v = classical ? Evaluation<NO_TRACE>(pos).value() : adjusted_NNUE();
+ // Use classical evaluation for really low piece endgames.
+ // The most critical case is a bishop + A/H file pawn vs naked king draw.
+ bool strongClassical = pos.non_pawn_material() < 2 * RookValueMg && pos.count<PAWN>() < 2;
+
+ v = classical || strongClassical ? Evaluation<NO_TRACE>(pos).value() : adjusted_NNUE();
// If the classical eval is small and imbalance large, use NNUE nevertheless.
// For the case of opposite colored bishops, switch to NNUE eval with
// small probability if the classical eval is less than the threshold.
// If the classical eval is small and imbalance large, use NNUE nevertheless.
// For the case of opposite colored bishops, switch to NNUE eval with
// small probability if the classical eval is less than the threshold.
- if ( largePsq
- && (abs(v) * 16 < NNUEThreshold2 * r50
- || ( pos.opposite_bishops()
- && abs(v) * 16 < (NNUEThreshold1 + pos.non_pawn_material() / 64) * r50
- && !(pos.this_thread()->nodes & 0xB))))
+ if ( largePsq && !strongClassical
+ && ( abs(v) * 16 < NNUEThreshold2 * r50
+ || ( pos.opposite_bishops()
+ && abs(v) * 16 < (NNUEThreshold1 + pos.non_pawn_material() / 64) * r50
+ && !(pos.this_thread()->nodes & 0xB))))