/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, 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
namespace {
+ enum ExtendedPieceType { // Used for tracing
+ PST = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL
+ };
+
+ namespace Tracing {
+
+ Score scores[COLOR_NB][TOTAL + 1];
+ std::stringstream stream;
+
+ void add(int idx, Score term_w, Score term_b = SCORE_ZERO);
+ void row(const char* name, int idx);
+ std::string do_trace(const Position& pos);
+ }
+
// Struct EvalInfo contains various information computed and collected
// by the evaluation functions.
struct EvalInfo {
// king is on g8 and there's a white knight on g5, this knight adds
// 2 to kingAdjacentZoneAttacksCount[BLACK].
int kingAdjacentZoneAttacksCount[COLOR_NB];
+
+ Bitboard pinnedPieces[COLOR_NB];
};
// Evaluation grain size, must be a power of 2
S(289, 344), S(233, 201), S(221, 273), S(46, 0), S(271, 0), S(307, 0)
};
- // MobilityBonus[PieceType][attacked] contains mobility bonuses for middle and
- // end game, indexed by piece type and number of attacked squares not occupied
- // by friendly pieces.
+ // MobilityBonus[PieceType][attacked] contains bonuses for middle and end
+ // game, indexed by piece type and number of attacked squares not occupied by
+ // friendly pieces.
const Score MobilityBonus[][32] = {
{}, {},
{ S(-35,-30), S(-22,-20), S(-9,-10), S( 3, 0), S(15, 10), S(27, 20), // Knights
S( 37, 28), S( 42, 31), S(44, 33) },
{ S(-22,-27), S( -8,-13), S( 6, 1), S(20, 15), S(34, 29), S(48, 43), // Bishops
S( 60, 55), S( 68, 63), S(74, 68), S(77, 72), S(80, 75), S(82, 77),
- S( 84, 79), S( 86, 81), S(87, 82), S(87, 82) },
+ S( 84, 79), S( 86, 81) },
{ S(-17,-33), S(-11,-16), S(-5, 0), S( 1, 16), S( 7, 32), S(13, 48), // Rooks
S( 18, 64), S( 22, 80), S(26, 96), S(29,109), S(31,115), S(33,119),
- S( 35,122), S( 36,123), S(37,124), S(38,124) },
+ S( 35,122), S( 36,123), S(37,124) },
{ S(-12,-20), S( -8,-13), S(-5, -7), S(-2, -1), S( 1, 5), S( 4, 11), // Queens
S( 7, 17), S( 10, 23), S(13, 29), S(16, 34), S(18, 38), S(20, 40),
S( 22, 41), S( 23, 41), S(24, 41), S(25, 41), S(25, 41), S(25, 41),
S( 25, 41), S( 25, 41), S(25, 41), S(25, 41), S(25, 41), S(25, 41),
- S( 25, 41), S( 25, 41), S(25, 41), S(25, 41), S(25, 41), S(25, 41),
- S( 25, 41), S( 25, 41) }
+ S( 25, 41), S( 25, 41), S(25, 41), S(25, 41) }
};
- // OutpostBonus[PieceType][Square] contains outpost bonuses of knights and
- // bishops, indexed by piece type and square (from white's point of view).
- const Value OutpostBonus[][SQUARE_NB] = {
+ // Outpost[PieceType][Square] contains bonuses for knights and bishops outposts,
+ // indexed by piece type and square (from white's point of view).
+ const Value Outpost[][SQUARE_NB] = {
{
// A B C D E F G H
V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Knights
V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0) }
};
- // ThreatBonus[attacking][attacked] contains threat bonuses according to
- // which piece type attacks which one.
- const Score ThreatBonus[][PIECE_TYPE_NB] = {
- {}, {},
- { S(0, 0), S( 7, 39), S( 0, 0), S(24, 49), S(41,100), S(41,100) }, // KNIGHT
- { S(0, 0), S( 7, 39), S(24, 49), S( 0, 0), S(41,100), S(41,100) }, // BISHOP
- { S(0, 0), S( 0, 22), S(15, 49), S(15, 49), S( 0, 0), S(24, 49) }, // ROOK
- { S(0, 0), S(15, 39), S(15, 39), S(15, 39), S(15, 39), S( 0, 0) } // QUEEN
+ // Threat[attacking][attacked] contains bonuses according to which piece
+ // type attacks which one.
+ const Score Threat[][PIECE_TYPE_NB] = {
+ { S(0, 0), S( 7, 39), S(24, 49), S(24, 49), S(41,100), S(41,100) }, // Minor
+ { S(0, 0), S(15, 39), S(15, 45), S(15, 45), S(15, 45), S(24, 49) }, // Major
};
- // ThreatenedByPawnPenalty[PieceType] contains a penalty according to which
- // piece type is attacked by an enemy pawn.
- const Score ThreatenedByPawnPenalty[] = {
+ // ThreatenedByPawn[PieceType] contains a penalty according to which piece
+ // type is attacked by an enemy pawn.
+ const Score ThreatenedByPawn[] = {
S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
};
#undef S
- const Score Tempo = make_score(24, 11);
-
- const Score BishopPinBonus = make_score(66, 11);
- const Score RookOn7thBonus = make_score(11, 20);
- const Score QueenOn7thBonus = make_score( 3, 8);
- const Score RookOnPawnBonus = make_score(10, 28);
- const Score QueenOnPawnBonus = make_score( 4, 20);
- const Score RookOpenFileBonus = make_score(43, 21);
- const Score RookHalfOpenFileBonus = make_score(19, 10);
- const Score BishopPawnsPenalty = make_score( 8, 12);
- const Score UndefendedMinorPenalty = make_score(25, 10);
- const Score TrappedRookPenalty = make_score(90, 0);
+ const Score Tempo = make_score(24, 11);
+ const Score RookOn7th = make_score(11, 20);
+ const Score QueenOn7th = make_score( 3, 8);
+ const Score RookOnPawn = make_score(10, 28);
+ const Score QueenOnPawn = make_score( 4, 20);
+ const Score RookOpenFile = make_score(43, 21);
+ const Score RookSemiopenFile = make_score(19, 10);
+ const Score BishopPawns = make_score( 8, 12);
+ const Score KnightPawns = make_score( 8, 4);
+ const Score MinorBehindPawn = make_score(16, 0);
+ const Score UndefendedMinor = make_score(25, 10);
+ const Score TrappedRook = make_score(90, 0);
+ const Score Unstoppable = make_score( 0, 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
// happen in Chess960 games.
- const Score TrappedBishopA1H1Penalty = make_score(50, 50);
+ const Score TrappedBishopA1H1 = make_score(50, 50);
- // The SpaceMask[Color] contains the area of the board which is considered
- // by the space evaluation. In the middle game, each side is given a bonus
+ // SpaceMask[Color] contains the area of the board which is considered
+ // by the space evaluation. In the middlegame, each side is given a bonus
// based on how many squares inside this area are safe and available for
// friendly minor pieces.
const Bitboard SpaceMask[] = {
- (1ULL << SQ_C2) | (1ULL << SQ_D2) | (1ULL << SQ_E2) | (1ULL << SQ_F2) |
- (1ULL << SQ_C3) | (1ULL << SQ_D3) | (1ULL << SQ_E3) | (1ULL << SQ_F3) |
- (1ULL << SQ_C4) | (1ULL << SQ_D4) | (1ULL << SQ_E4) | (1ULL << SQ_F4),
- (1ULL << SQ_C7) | (1ULL << SQ_D7) | (1ULL << SQ_E7) | (1ULL << SQ_F7) |
- (1ULL << SQ_C6) | (1ULL << SQ_D6) | (1ULL << SQ_E6) | (1ULL << SQ_F6) |
- (1ULL << SQ_C5) | (1ULL << SQ_D5) | (1ULL << SQ_E5) | (1ULL << SQ_F5)
+ (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank2BB | Rank3BB | Rank4BB),
+ (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank7BB | Rank6BB | Rank5BB)
};
// King danger constants and variables. The king danger scores are taken
- // from the KingDangerTable[]. Various little "meta-bonuses" measuring
- // the strength of the enemy attack are added up into an integer, which
- // is used as an index to KingDangerTable[].
+ // from KingDanger[]. Various little "meta-bonuses" measuring the strength
+ // of the enemy attack are added up into an integer, which is used as an
+ // index to KingDanger[].
//
// KingAttackWeights[PieceType] contains king attack weights by piece type
const int KingAttackWeights[] = { 0, 0, 2, 2, 3, 5 };
// Bonuses for enemy's safe checks
- const int QueenContactCheckBonus = 6;
- const int RookContactCheckBonus = 4;
- const int QueenCheckBonus = 3;
- const int RookCheckBonus = 2;
- const int BishopCheckBonus = 1;
- const int KnightCheckBonus = 1;
-
- // InitKingDanger[Square] contains penalties based on the position of the
- // defending king, indexed by king's square (from white's point of view).
- const int InitKingDanger[] = {
- 2, 0, 2, 5, 5, 2, 0, 2,
- 2, 2, 4, 8, 8, 4, 2, 2,
- 7, 10, 12, 12, 12, 12, 10, 7,
- 15, 15, 15, 15, 15, 15, 15, 15,
- 15, 15, 15, 15, 15, 15, 15, 15,
- 15, 15, 15, 15, 15, 15, 15, 15,
- 15, 15, 15, 15, 15, 15, 15, 15,
- 15, 15, 15, 15, 15, 15, 15, 15
- };
-
- // KingDangerTable[Color][attackUnits] contains the actual king danger
- // weighted scores, indexed by color and by a calculated integer number.
- Score KingDangerTable[COLOR_NB][128];
+ const int QueenContactCheck = 24;
+ const int RookContactCheck = 16;
+ const int QueenCheck = 12;
+ const int RookCheck = 8;
+ const int BishopCheck = 2;
+ const int KnightCheck = 3;
- // TracedTerms[Color][PieceType || TracedType] contains a breakdown of the
- // evaluation terms, used when tracing.
- Score TracedScores[COLOR_NB][16];
- std::stringstream TraceStream;
-
- enum TracedType {
- PST = 8, IMBALANCE = 9, MOBILITY = 10, THREAT = 11,
- PASSED = 12, UNSTOPPABLE = 13, SPACE = 14, TOTAL = 15
- };
+ // KingDanger[Color][attackUnits] contains the actual king danger weighted
+ // scores, indexed by color and by a calculated integer number.
+ Score KingDanger[COLOR_NB][128];
// Function prototypes
template<bool Trace>
- Value do_evaluate(const Position& pos, Value& margin);
+ Value do_evaluate(const Position& pos);
template<Color Us>
void init_eval_info(const Position& pos, EvalInfo& ei);
template<Color Us, bool Trace>
- Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility);
+ Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score* mobility);
template<Color Us, bool Trace>
- Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]);
+ Score evaluate_king(const Position& pos, const EvalInfo& ei);
template<Color Us, bool Trace>
- Score evaluate_threats(const Position& pos, EvalInfo& ei);
+ Score evaluate_threats(const Position& pos, const EvalInfo& ei);
template<Color Us, bool Trace>
- Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
+ Score evaluate_passed_pawns(const Position& pos, const EvalInfo& ei);
template<Color Us>
- int evaluate_space(const Position& pos, EvalInfo& ei);
+ int evaluate_space(const Position& pos, const EvalInfo& ei);
- Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
+ Score evaluate_unstoppable_pawns(const Position& pos, Color us, const EvalInfo& ei);
Value interpolate(const Score& v, Phase ph, ScaleFactor sf);
Score apply_weight(Score v, Score w);
Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
double to_cp(Value v);
- void trace_add(int idx, Score term_w, Score term_b = SCORE_ZERO);
- void trace_row(const char* name, int idx);
}
namespace Eval {
/// evaluate() is the main evaluation function. It always computes two
- /// values, an endgame score and a middle game score, and interpolates
+ /// values, an endgame score and a middlegame score, and interpolates
/// between them based on the remaining material.
- Value evaluate(const Position& pos, Value& margin) {
- return do_evaluate<false>(pos, margin);
+ Value evaluate(const Position& pos) {
+ return do_evaluate<false>(pos);
+ }
+
+
+ /// trace() is like evaluate(), but instead of returning a value, it returns
+ /// a string (suitable for outputting to stdout) that contains the detailed
+ /// descriptions and values of each evaluation term. It's mainly used for
+ /// debugging.
+ std::string trace(const Position& pos) {
+ return Tracing::do_trace(pos);
}
const int MaxSlope = 30;
const int Peak = 1280;
- for (int t = 0, i = 1; i < 100; i++)
+ for (int t = 0, i = 1; i < 100; ++i)
{
t = std::min(Peak, std::min(int(0.4 * i * i), t + MaxSlope));
- KingDangerTable[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]);
- KingDangerTable[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]);
+ KingDanger[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]);
+ KingDanger[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]);
}
}
-
- /// trace() is like evaluate() but instead of a value returns a string suitable
- /// to be print on stdout with the detailed descriptions and values of each
- /// evaluation term. Used mainly for debugging.
-
- std::string trace(const Position& pos) {
-
- Value margin;
- std::string totals;
-
- Search::RootColor = pos.side_to_move();
-
- TraceStream.str("");
- TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
- memset(TracedScores, 0, 2 * 16 * sizeof(Score));
-
- do_evaluate<true>(pos, margin);
-
- totals = TraceStream.str();
- TraceStream.str("");
-
- TraceStream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
- << " | MG EG | MG EG | MG EG \n"
- << "---------------------+-------------+-------------+---------------\n";
-
- trace_row("Material, PST, Tempo", PST);
- trace_row("Material imbalance", IMBALANCE);
- trace_row("Pawns", PAWN);
- trace_row("Knights", KNIGHT);
- trace_row("Bishops", BISHOP);
- trace_row("Rooks", ROOK);
- trace_row("Queens", QUEEN);
- trace_row("Mobility", MOBILITY);
- trace_row("King safety", KING);
- trace_row("Threats", THREAT);
- trace_row("Passed pawns", PASSED);
- trace_row("Unstoppable pawns", UNSTOPPABLE);
- trace_row("Space", SPACE);
-
- TraceStream << "---------------------+-------------+-------------+---------------\n";
- trace_row("Total", TOTAL);
- TraceStream << totals;
-
- return TraceStream.str();
- }
-
} // namespace Eval
namespace {
template<bool Trace>
-Value do_evaluate(const Position& pos, Value& margin) {
+Value do_evaluate(const Position& pos) {
assert(!pos.checkers());
EvalInfo ei;
- Value margins[COLOR_NB];
- Score score, mobilityWhite, mobilityBlack;
+ Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO };
Thread* th = pos.this_thread();
- // margins[] store the uncertainty estimation of position's evaluation
- // that typically is used by the search for pruning decisions.
- margins[WHITE] = margins[BLACK] = VALUE_ZERO;
-
// Initialize score by reading the incrementally updated scores included
- // in the position object (material + piece square tables) and adding
+ // in the position object (material + piece square tables) and adding a
// Tempo bonus. Score is computed from the point of view of white.
score = pos.psq_score() + (pos.side_to_move() == WHITE ? Tempo : -Tempo);
// If we have a specialized evaluation function for the current material
// configuration, call it and return.
if (ei.mi->specialized_eval_exists())
- {
- margin = VALUE_ZERO;
return ei.mi->evaluate(pos);
- }
// Probe the pawn hash table
ei.pi = Pawns::probe(pos, th->pawnsTable);
init_eval_info<BLACK>(pos, ei);
// Evaluate pieces and mobility
- score += evaluate_pieces_of_color<WHITE, Trace>(pos, ei, mobilityWhite)
- - evaluate_pieces_of_color<BLACK, Trace>(pos, ei, mobilityBlack);
+ score += evaluate_pieces_of_color<WHITE, Trace>(pos, ei, mobility)
+ - evaluate_pieces_of_color<BLACK, Trace>(pos, ei, mobility);
- score += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
+ score += apply_weight(mobility[WHITE] - mobility[BLACK], Weights[Mobility]);
// Evaluate kings after all other pieces because we need complete attack
// information when computing the king safety evaluation.
- score += evaluate_king<WHITE, Trace>(pos, ei, margins)
- - evaluate_king<BLACK, Trace>(pos, ei, margins);
+ score += evaluate_king<WHITE, Trace>(pos, ei)
+ - evaluate_king<BLACK, Trace>(pos, ei);
// Evaluate tactical threats, we need full attack information including king
score += evaluate_threats<WHITE, Trace>(pos, ei)
score += evaluate_passed_pawns<WHITE, Trace>(pos, ei)
- evaluate_passed_pawns<BLACK, Trace>(pos, ei);
- // If one side has only a king, check whether exists any unstoppable passed pawn
+ // If one side has only a king, score for potential unstoppable pawns
if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
- score += evaluate_unstoppable_pawns(pos, ei);
+ score += evaluate_unstoppable_pawns(pos, WHITE, ei)
+ - evaluate_unstoppable_pawns(pos, BLACK, ei);
- // Evaluate space for both sides, only in middle-game.
+ // Evaluate space for both sides, only in middlegame
if (ei.mi->space_weight())
{
int s = evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei);
- score += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]);
+ score += apply_weight(s * ei.mi->space_weight(), Weights[Space]);
}
- // Scale winning side if position is more drawish that what it appears
+ // Scale winning side if position is more drawish than it appears
ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE)
: ei.mi->scale_factor(pos, BLACK);
&& pos.opposite_bishops()
&& sf == SCALE_FACTOR_NORMAL)
{
- // Only the two bishops ?
+ // Ignoring any pawns, do both sides only have a single bishop and no
+ // other pieces?
if ( pos.non_pawn_material(WHITE) == BishopValueMg
&& pos.non_pawn_material(BLACK) == BishopValueMg)
{
// Check for KBP vs KB with only a single pawn that is almost
// certainly a draw or at least two pawns.
- bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
+ bool one_pawn = (pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK) == 1);
sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
}
else
sf = ScaleFactor(50);
}
- margin = margins[pos.side_to_move()];
Value v = interpolate(score, ei.mi->game_phase(), sf);
// In case of tracing add all single evaluation contributions for both white and black
if (Trace)
{
- trace_add(PST, pos.psq_score());
- trace_add(IMBALANCE, ei.mi->material_value());
- trace_add(PAWN, ei.pi->pawns_value());
- trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns(pos, ei));
- Score w = make_score(ei.mi->space_weight() * evaluate_space<WHITE>(pos, ei), 0);
- Score b = make_score(ei.mi->space_weight() * evaluate_space<BLACK>(pos, ei), 0);
- trace_add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
- trace_add(TOTAL, score);
- TraceStream << "\nUncertainty margin: White: " << to_cp(margins[WHITE])
- << ", Black: " << to_cp(margins[BLACK])
- << "\nScaling: " << std::noshowpos
- << std::setw(6) << 100.0 * ei.mi->game_phase() / 128.0 << "% MG, "
- << std::setw(6) << 100.0 * (1.0 - ei.mi->game_phase() / 128.0) << "% * "
- << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
- << "Total evaluation: " << to_cp(v);
+ Tracing::add(PST, pos.psq_score());
+ Tracing::add(IMBALANCE, ei.mi->material_value());
+ Tracing::add(PAWN, ei.pi->pawns_value());
+ Score w = ei.mi->space_weight() * evaluate_space<WHITE>(pos, ei);
+ Score b = ei.mi->space_weight() * evaluate_space<BLACK>(pos, ei);
+ Tracing::add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
+ Tracing::add(TOTAL, score);
+ Tracing::stream << "\nScaling: " << std::noshowpos
+ << std::setw(6) << 100.0 * ei.mi->game_phase() / 128.0 << "% MG, "
+ << std::setw(6) << 100.0 * (1.0 - ei.mi->game_phase() / 128.0) << "% * "
+ << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
+ << "Total evaluation: " << to_cp(v);
}
return pos.side_to_move() == WHITE ? v : -v;
template<Color Us>
void init_eval_info(const Position& pos, EvalInfo& ei) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Square Down = (Us == WHITE ? DELTA_S : DELTA_N);
+
+ ei.pinnedPieces[Us] = pos.pinned_pieces(Us);
Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
// Init king safety tables only if we are going to use them
- if ( pos.piece_count(Us, QUEEN)
- && pos.non_pawn_material(Us) > QueenValueMg + PawnValueMg)
+ if (pos.count<QUEEN>(Us) && pos.non_pawn_material(Us) > QueenValueMg + PawnValueMg)
{
- ei.kingRing[Them] = (b | (Us == WHITE ? b >> 8 : b << 8));
+ ei.kingRing[Them] = b | shift_bb<Down>(b);
b &= ei.attackedBy[Us][PAWN];
- ei.kingAttackersCount[Us] = b ? popcount<Max15>(b) / 2 : 0;
+ ei.kingAttackersCount[Us] = b ? popcount<Max15>(b) : 0;
ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
- } else
+ }
+ else
ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0;
}
- // evaluate_outposts() evaluates bishop and knight outposts squares
+ // evaluate_outposts() evaluates bishop and knight outpost squares
template<PieceType Piece, Color Us>
Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
assert (Piece == BISHOP || Piece == KNIGHT);
// Initial bonus based on square
- Value bonus = OutpostBonus[Piece == BISHOP][relative_square(Us, s)];
+ Value bonus = Outpost[Piece == BISHOP][relative_square(Us, s)];
// Increase bonus if supported by pawn, especially if the opponent has
- // no minor piece which can exchange the outpost piece.
+ // no minor piece which can trade with the outpost piece.
if (bonus && (ei.attackedBy[Us][PAWN] & s))
{
if ( !pos.pieces(Them, KNIGHT)
- && !(same_color_squares(s) & pos.pieces(Them, BISHOP)))
+ && !(squares_of_color(s) & pos.pieces(Them, BISHOP)))
bonus += bonus + bonus / 2;
else
bonus += bonus / 2;
}
+
return make_score(bonus, bonus);
}
- // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
+ // evaluate_pieces() assigns bonuses and penalties to the pieces of a given color
template<PieceType Piece, Color Us, bool Trace>
- Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
+ Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, Bitboard mobilityArea) {
Bitboard b;
Square s;
Score score = SCORE_ZERO;
const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Square* pl = pos.piece_list(Us, Piece);
+ const Square* pl = pos.list<Piece>(Us);
ei.attackedBy[Us][Piece] = 0;
: Piece == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN))
: pos.attacks_from<Piece>(s);
+ if (ei.pinnedPieces[Us] & s)
+ b &= LineBB[pos.king_square(Us)][s];
+
ei.attackedBy[Us][Piece] |= b;
if (b & ei.kingRing[Them])
{
ei.kingAttackersCount[Us]++;
ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
- Bitboard bb = (b & ei.attackedBy[Them][KING]);
+ Bitboard bb = b & ei.attackedBy[Them][KING];
if (bb)
ei.kingAdjacentZoneAttacksCount[Us] += popcount<Max15>(bb);
}
- int mob = popcount<Piece == QUEEN ? Full : Max15>(b & mobilityArea);
- mobility += MobilityBonus[Piece][mob];
+ int mob = Piece != QUEEN ? popcount<Max15>(b & mobilityArea)
+ : popcount<Full >(b & mobilityArea);
- // Decrease score if we are attacked by an enemy pawn. Remaining part
+ mobility[Us] += MobilityBonus[Piece][mob];
+
+ // Decrease score if we are attacked by an enemy pawn. The remaining part
// of threat evaluation must be done later when we have full attack info.
if (ei.attackedBy[Them][PAWN] & s)
- score -= ThreatenedByPawnPenalty[Piece];
-
- // Otherwise give a bonus if we are a bishop and can pin a piece or can
- // give a discovered check through an x-ray attack.
- else if ( Piece == BISHOP
- && (PseudoAttacks[Piece][pos.king_square(Them)] & s)
- && !more_than_one(BetweenBB[s][pos.king_square(Them)] & pos.pieces()))
- score += BishopPinBonus;
+ score -= ThreatenedByPawn[Piece];
// Penalty for bishop with same coloured pawns
if (Piece == BISHOP)
- score -= BishopPawnsPenalty * ei.pi->pawns_on_same_color_squares(Us, s);
+ score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s);
+
+ // Penalty for knight when there are few enemy pawns
+ if (Piece == KNIGHT)
+ score -= KnightPawns * std::max(5 - pos.count<PAWN>(Them), 0);
- // Bishop and knight outposts squares
- if ( (Piece == BISHOP || Piece == KNIGHT)
- && !(pos.pieces(Them, PAWN) & attack_span_mask(Us, s)))
- score += evaluate_outposts<Piece, Us>(pos, ei, s);
+ if (Piece == BISHOP || Piece == KNIGHT)
+ {
+ // Bishop and knight outposts squares
+ if (!(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s)))
+ score += evaluate_outposts<Piece, Us>(pos, ei, s);
+
+ // Bishop or knight behind a pawn
+ if ( relative_rank(Us, s) < RANK_5
+ && (pos.pieces(PAWN) & (s + pawn_push(Us))))
+ score += MinorBehindPawn;
+ }
if ( (Piece == ROOK || Piece == QUEEN)
&& relative_rank(Us, s) >= RANK_5)
// Major piece on 7th rank and enemy king trapped on 8th
if ( relative_rank(Us, s) == RANK_7
&& relative_rank(Us, pos.king_square(Them)) == RANK_8)
- score += Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus;
+ score += Piece == ROOK ? RookOn7th : QueenOn7th;
- // Major piece attacking enemy pawns on the same rank
- Bitboard pawns = pos.pieces(Them, PAWN) & rank_bb(s);
+ // Major piece attacking enemy pawns on the same rank/file
+ Bitboard pawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s];
if (pawns)
- score += popcount<Max15>(pawns) * (Piece == ROOK ? RookOnPawnBonus : QueenOnPawnBonus);
+ score += popcount<Max15>(pawns) * (Piece == ROOK ? RookOnPawn : QueenOnPawn);
}
// Special extra evaluation for rooks
if (Piece == ROOK)
{
- // Give a bonus for a rook on a open or half-open file
- if (ei.pi->half_open(Us, file_of(s)))
- score += ei.pi->half_open(Them, file_of(s)) ? RookOpenFileBonus
- : RookHalfOpenFileBonus;
- if (mob > 6 || ei.pi->half_open(Us, file_of(s)))
+ // Give a bonus for a rook on a open or semi-open file
+ if (ei.pi->semiopen(Us, file_of(s)))
+ score += ei.pi->semiopen(Them, file_of(s)) ? RookOpenFile : RookSemiopenFile;
+
+ if (mob > 3 || ei.pi->semiopen(Us, file_of(s)))
continue;
Square ksq = pos.king_square(Us);
- // Penalize rooks which are trapped inside a king. Penalize more if
- // king has lost right to castle.
+ // Penalize rooks which are trapped by a king. Penalize more if the
+ // king has lost its castling capability.
if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
&& (rank_of(ksq) == rank_of(s) || relative_rank(Us, ksq) == RANK_1)
- && !ei.pi->half_open_on_side(Us, file_of(ksq), file_of(ksq) < FILE_E))
- score -= (TrappedRookPenalty - make_score(mob * 8, 0)) * (pos.can_castle(Us) ? 1 : 2);
+ && !ei.pi->semiopen_on_side(Us, file_of(ksq), file_of(ksq) < FILE_E))
+ score -= (TrappedRook - make_score(mob * 8, 0)) * (pos.can_castle(Us) ? 1 : 2);
}
// An important Chess960 pattern: A cornered bishop blocked by a friendly
const enum Piece P = make_piece(Us, PAWN);
Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
if (pos.piece_on(s + d) == P)
- score -= !pos.is_empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1Penalty * 4
- : pos.piece_on(s + d + d) == P ? TrappedBishopA1H1Penalty * 2
- : TrappedBishopA1H1Penalty;
+ score -= !pos.empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4
+ : pos.piece_on(s + d + d) == P ? TrappedBishopA1H1 * 2
+ : TrappedBishopA1H1;
}
}
if (Trace)
- TracedScores[Us][Piece] = score;
+ Tracing::scores[Us][Piece] = score;
return score;
}
- // evaluate_threats<>() assigns bonuses according to the type of attacking piece
- // and the type of attacked one.
-
- template<Color Us, bool Trace>
- Score evaluate_threats(const Position& pos, EvalInfo& ei) {
-
- const Color Them = (Us == WHITE ? BLACK : WHITE);
-
- Bitboard b, undefendedMinors, weakEnemies;
- Score score = SCORE_ZERO;
-
- // Undefended minors get penalized even if not under attack
- undefendedMinors = pos.pieces(Them, BISHOP, KNIGHT)
- & ~ei.attackedBy[Them][ALL_PIECES];
-
- if (undefendedMinors)
- score += UndefendedMinorPenalty;
-
- // Enemy pieces not defended by a pawn and under our attack
- weakEnemies = pos.pieces(Them)
- & ~ei.attackedBy[Them][PAWN]
- & ei.attackedBy[Us][ALL_PIECES];
-
- // Add bonus according to type of attacked enemy piece and to the
- // type of attacking piece, from knights to queens. Kings are not
- // considered because are already handled in king evaluation.
- if (weakEnemies)
- for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
- {
- b = ei.attackedBy[Us][pt1] & weakEnemies;
- if (b)
- for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
- if (b & pos.pieces(pt2))
- score += ThreatBonus[pt1][pt2];
- }
-
- if (Trace)
- TracedScores[Us][THREAT] = score;
-
- return score;
- }
-
-
- // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
+ // evaluate_pieces_of_color() assigns bonuses and penalties to all the
// pieces of a given color.
template<Color Us, bool Trace>
- Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) {
+ Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score* mobility) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
- Score score = mobility = SCORE_ZERO;
-
// Do not include in mobility squares protected by enemy pawns or occupied by our pieces
const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces(Us, PAWN, KING));
- score += evaluate_pieces<KNIGHT, Us, Trace>(pos, ei, mobility, mobilityArea);
- score += evaluate_pieces<BISHOP, Us, Trace>(pos, ei, mobility, mobilityArea);
- score += evaluate_pieces<ROOK, Us, Trace>(pos, ei, mobility, mobilityArea);
- score += evaluate_pieces<QUEEN, Us, Trace>(pos, ei, mobility, mobilityArea);
+ Score score = evaluate_pieces<KNIGHT, Us, Trace>(pos, ei, mobility, mobilityArea)
+ + evaluate_pieces<BISHOP, Us, Trace>(pos, ei, mobility, mobilityArea)
+ + evaluate_pieces<ROOK, Us, Trace>(pos, ei, mobility, mobilityArea)
+ + evaluate_pieces<QUEEN, Us, Trace>(pos, ei, mobility, mobilityArea);
- // Sum up all attacked squares
- ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
- | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
- | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
+ // Sum up all attacked squares (updated in evaluate_pieces)
+ ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
+ | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
+ | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
if (Trace)
- TracedScores[Us][MOBILITY] = apply_weight(mobility, Weights[Mobility]);
+ Tracing::scores[Us][MOBILITY] = apply_weight(mobility[Us], Weights[Mobility]);
return score;
}
- // evaluate_king<>() assigns bonuses and penalties to a king of a given color
+ // evaluate_king() assigns bonuses and penalties to a king of a given color
template<Color Us, bool Trace>
- Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
+ Score evaluate_king(const Position& pos, const EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
// King shelter and enemy pawns storm
Score score = ei.pi->king_safety<Us>(pos, ksq);
- // King safety. This is quite complicated, and is almost certainly far
- // from optimally tuned.
- if ( ei.kingAttackersCount[Them] >= 2
- && ei.kingAdjacentZoneAttacksCount[Them])
+ // Main king safety evaluation
+ if (ei.kingAttackersCount[Them])
{
- // Find the attacked squares around the king which has no defenders
+ // Find the attacked squares around the king which have no defenders
// apart from the king itself
- undefended = ei.attackedBy[Them][ALL_PIECES] & ei.attackedBy[Us][KING];
- undefended &= ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
+ undefended = ei.attackedBy[Them][ALL_PIECES]
+ & ei.attackedBy[Us][KING]
+ & ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
| ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
| ei.attackedBy[Us][QUEEN]);
// Initialize the 'attackUnits' variable, which is used later on as an
- // index to the KingDangerTable[] array. The initial value is based on
- // the number and types of the enemy's attacking pieces, the number of
- // attacked and undefended squares around our king, the square of the
- // king, and the quality of the pawn shelter.
- attackUnits = std::min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
+ // index to the KingDanger[] array. The initial value is based on the
+ // 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(20, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
+ 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount<Max15>(undefended))
- + InitKingDanger[relative_square(Us, ksq)]
- mg_value(score) / 32;
- // Analyse enemy's safe queen contact checks. First find undefended
- // squares around the king attacked by enemy queen...
+ // Analyse the enemy's safe queen contact checks. Firstly, find the
+ // undefended squares around the king that are attacked by the enemy's
+ // queen...
b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
if (b)
{
- // ...then remove squares not supported by another enemy piece
+ // ...and then remove squares not supported by another enemy piece
b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
| ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
if (b)
- attackUnits += QueenContactCheckBonus
+ attackUnits += QueenContactCheck
* popcount<Max15>(b)
* (Them == pos.side_to_move() ? 2 : 1);
}
- // Analyse enemy's safe rook contact checks. First find undefended
- // squares around the king attacked by enemy rooks...
+ // Analyse the enemy's safe rook contact checks. Firstly, find the
+ // undefended squares around the king that are attacked by the enemy's
+ // rooks...
b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
- // Consider only squares where the enemy rook gives check
+ // Consider only squares where the enemy's rook gives check
b &= PseudoAttacks[ROOK][ksq];
if (b)
{
- // ...then remove squares not supported by another enemy piece
+ // ...and then remove squares not supported by another enemy piece
b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
| ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]);
if (b)
- attackUnits += RookContactCheckBonus
+ attackUnits += RookContactCheck
* popcount<Max15>(b)
* (Them == pos.side_to_move() ? 2 : 1);
}
- // Analyse enemy's safe distance checks for sliders and knights
+ // Analyse the enemy's safe distance checks for sliders and knights
safe = ~(pos.pieces(Them) | ei.attackedBy[Us][ALL_PIECES]);
b1 = pos.attacks_from<ROOK>(ksq) & safe;
// Enemy queen safe checks
b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
if (b)
- attackUnits += QueenCheckBonus * popcount<Max15>(b);
+ attackUnits += QueenCheck * popcount<Max15>(b);
// Enemy rooks safe checks
b = b1 & ei.attackedBy[Them][ROOK];
if (b)
- attackUnits += RookCheckBonus * popcount<Max15>(b);
+ attackUnits += RookCheck * popcount<Max15>(b);
// Enemy bishops safe checks
b = b2 & ei.attackedBy[Them][BISHOP];
if (b)
- attackUnits += BishopCheckBonus * popcount<Max15>(b);
+ attackUnits += BishopCheck * popcount<Max15>(b);
// Enemy knights safe checks
b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
if (b)
- attackUnits += KnightCheckBonus * popcount<Max15>(b);
+ attackUnits += KnightCheck * popcount<Max15>(b);
- // To index KingDangerTable[] attackUnits must be in [0, 99] range
+ // To index KingDanger[] attackUnits must be in [0, 99] range
attackUnits = std::min(99, std::max(0, attackUnits));
- // Finally, extract the king danger score from the KingDangerTable[]
- // array and subtract the score from evaluation. Set also margins[]
- // value that will be used for pruning because this value can sometimes
- // be very big, and so capturing a single attacking piece can therefore
- // result in a score change far bigger than the value of the captured piece.
- score -= KingDangerTable[Us == Search::RootColor][attackUnits];
- margins[Us] += mg_value(KingDangerTable[Us == Search::RootColor][attackUnits]);
+ // Finally, extract the king danger score from the KingDanger[]
+ // array and subtract the score from evaluation.
+ score -= KingDanger[Us == Search::RootColor][attackUnits];
+ }
+
+ if (Trace)
+ Tracing::scores[Us][KING] = score;
+
+ return score;
+ }
+
+
+ // evaluate_threats() assigns bonuses according to the type of attacking piece
+ // and the type of attacked one.
+
+ template<Color Us, bool Trace>
+ Score evaluate_threats(const Position& pos, const EvalInfo& ei) {
+
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+
+ Bitboard b, undefendedMinors, weakEnemies;
+ Score score = SCORE_ZERO;
+
+ // Undefended minors get penalized even if they are not under attack
+ undefendedMinors = pos.pieces(Them, BISHOP, KNIGHT)
+ & ~ei.attackedBy[Them][ALL_PIECES];
+
+ if (undefendedMinors)
+ score += UndefendedMinor;
+
+ // Enemy pieces not defended by a pawn and under our attack
+ weakEnemies = pos.pieces(Them)
+ & ~ei.attackedBy[Them][PAWN]
+ & ei.attackedBy[Us][ALL_PIECES];
+
+ // Add a bonus according if the attacking pieces are minor or major
+ if (weakEnemies)
+ {
+ b = weakEnemies & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
+ if (b)
+ score += Threat[0][type_of(pos.piece_on(lsb(b)))];
+
+ b = weakEnemies & (ei.attackedBy[Us][ROOK] | ei.attackedBy[Us][QUEEN]);
+ if (b)
+ score += Threat[1][type_of(pos.piece_on(lsb(b)))];
}
if (Trace)
- TracedScores[Us][KING] = score;
+ Tracing::scores[Us][THREAT] = score;
return score;
}
- // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
+ // evaluate_passed_pawns() evaluates the passed pawns of the given color
template<Color Us, bool Trace>
- Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
+ Score evaluate_passed_pawns(const Position& pos, const EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
{
Square s = pop_lsb(&b);
- assert(pos.pawn_is_passed(Us, s));
+ assert(pos.pawn_passed(Us, s));
int r = int(relative_rank(Us, s) - RANK_2);
int rr = r * (r - 1);
// Base bonus based on rank
- Value mbonus = Value(20 * rr);
- Value ebonus = Value(10 * (rr + r + 1));
+ Value mbonus = Value(17 * rr);
+ Value ebonus = Value(7 * (rr + r + 1));
if (rr)
{
Square blockSq = s + pawn_push(Us);
- // Adjust bonus based on kings proximity
- ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 5 * rr);
- ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 2 * rr);
+ // Adjust bonus based on the king's proximity
+ ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 5 * rr)
+ - Value(square_distance(pos.king_square(Us ), blockSq) * 2 * rr);
// If blockSq is not the queening square then consider also a second push
- if (rank_of(blockSq) != (Us == WHITE ? RANK_8 : RANK_1))
+ if (relative_rank(Us, blockSq) != RANK_8)
ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
- // If the pawn is free to advance, increase bonus
- if (pos.is_empty(blockSq))
+ // If the pawn is free to advance, then increase the bonus
+ if (pos.empty(blockSq))
{
squaresToQueen = forward_bb(Us, s);
- defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES];
// If there is an enemy rook or queen attacking the pawn from behind,
// add all X-ray attacks by the rook or queen. Otherwise consider only
// the squares in the pawn's path attacked or occupied by the enemy.
- if ( (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN))
+ if ( unlikely(forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN))
&& (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN) & pos.attacks_from<ROOK>(s)))
unsafeSquares = squaresToQueen;
else
unsafeSquares = squaresToQueen & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
- // If there aren't enemy attacks huge bonus, a bit smaller if at
- // least block square is not attacked, otherwise smallest bonus.
+ if ( unlikely(forward_bb(Them, s) & pos.pieces(Us, ROOK, QUEEN))
+ && (forward_bb(Them, s) & pos.pieces(Us, ROOK, QUEEN) & pos.attacks_from<ROOK>(s)))
+ defendedSquares = squaresToQueen;
+ else
+ defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES];
+
+ // If there aren't any enemy attacks, then assign a huge bonus.
+ // The bonus will be a bit smaller if at least the block square
+ // isn't attacked, otherwise assign the smallest possible bonus.
int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 3;
- // Big bonus if the path to queen is fully defended, a bit less
- // if at least block square is defended.
+ // Assign a big bonus if the path to the queen is fully defended,
+ // otherwise assign a bit less of a bonus if at least the block
+ // square is defended.
if (defendedSquares == squaresToQueen)
k += 6;
{
if (pos.non_pawn_material(Them) <= KnightValueMg)
ebonus += ebonus / 4;
+
else if (pos.pieces(Them, ROOK, QUEEN))
ebonus -= ebonus / 4;
}
+
+ if (pos.count<PAWN>(Us) < pos.count<PAWN>(Them))
+ ebonus += ebonus / 4;
+
score += make_score(mbonus, ebonus);
}
if (Trace)
- TracedScores[Us][PASSED] = apply_weight(score, Weights[PassedPawns]);
+ Tracing::scores[Us][PASSED] = apply_weight(score, Weights[PassedPawns]);
- // Add the scores to the middle game and endgame eval
+ // Add the scores to the middlegame and endgame eval
return apply_weight(score, Weights[PassedPawns]);
}
- // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides, this is quite
- // conservative and returns a winning score only when we are very sure that the pawn is winning.
-
- Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
-
- Bitboard b, b2, blockers, supporters, queeningPath, candidates;
- Square s, blockSq, queeningSquare;
- Color c, winnerSide, loserSide;
- bool pathDefended, opposed;
- int pliesToGo, movesToGo, oppMovesToGo, sacptg, blockersCount, minKingDist, kingptg, d;
- int pliesToQueen[] = { 256, 256 };
-
- // Step 1. Hunt for unstoppable passed pawns. If we find at least one,
- // record how many plies are required for promotion.
- for (c = WHITE; c <= BLACK; c++)
- {
- // Skip if other side has non-pawn pieces
- if (pos.non_pawn_material(~c))
- continue;
-
- b = ei.pi->passed_pawns(c);
-
- while (b)
- {
- s = pop_lsb(&b);
- queeningSquare = relative_square(c, file_of(s) | RANK_8);
- queeningPath = forward_bb(c, s);
-
- // Compute plies to queening and check direct advancement
- movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(c, s) == RANK_2);
- oppMovesToGo = square_distance(pos.king_square(~c), queeningSquare) - int(c != pos.side_to_move());
- pathDefended = ((ei.attackedBy[c][ALL_PIECES] & queeningPath) == queeningPath);
-
- if (movesToGo >= oppMovesToGo && !pathDefended)
- continue;
-
- // Opponent king cannot block because path is defended and position
- // is not in check. So only friendly pieces can be blockers.
- assert(!pos.checkers());
- assert((queeningPath & pos.pieces()) == (queeningPath & pos.pieces(c)));
+ // evaluate_unstoppable_pawns() scores the most advanced among the passed and
+ // candidate pawns. In case opponent has no pieces but pawns, this is somewhat
+ // related to the possibility that pawns are unstoppable.
- // Add moves needed to free the path from friendly pieces and retest condition
- movesToGo += popcount<Max15>(queeningPath & pos.pieces(c));
+ Score evaluate_unstoppable_pawns(const Position& pos, Color us, const EvalInfo& ei) {
- if (movesToGo >= oppMovesToGo && !pathDefended)
- continue;
+ Bitboard b = ei.pi->passed_pawns(us) | ei.pi->candidate_pawns(us);
- pliesToGo = 2 * movesToGo - int(c == pos.side_to_move());
- pliesToQueen[c] = std::min(pliesToQueen[c], pliesToGo);
- }
- }
-
- // Step 2. If either side cannot promote at least three plies before the other side then situation
- // becomes too complex and we give up. Otherwise we determine the possibly "winning side"
- if (abs(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3)
+ if (!b || pos.non_pawn_material(~us))
return SCORE_ZERO;
- winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK);
- loserSide = ~winnerSide;
-
- // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
- b = candidates = pos.pieces(loserSide, PAWN);
-
- while (b)
- {
- s = pop_lsb(&b);
-
- // Compute plies from queening
- queeningSquare = relative_square(loserSide, file_of(s) | RANK_8);
- movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
- pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
-
- // Check if (without even considering any obstacles) we're too far away or doubled
- if ( pliesToQueen[winnerSide] + 3 <= pliesToGo
- || (forward_bb(loserSide, s) & pos.pieces(loserSide, PAWN)))
- candidates ^= s;
- }
-
- // If any candidate is already a passed pawn it _may_ promote in time. We give up.
- if (candidates & ei.pi->passed_pawns(loserSide))
- return SCORE_ZERO;
-
- // Step 4. Check new passed pawn creation through king capturing and pawn sacrifices
- b = candidates;
-
- while (b)
- {
- s = pop_lsb(&b);
- sacptg = blockersCount = 0;
- minKingDist = kingptg = 256;
-
- // Compute plies from queening
- queeningSquare = relative_square(loserSide, file_of(s) | RANK_8);
- movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
- pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
-
- // Generate list of blocking pawns and supporters
- supporters = adjacent_files_bb(file_of(s)) & candidates;
- opposed = forward_bb(loserSide, s) & pos.pieces(winnerSide, PAWN);
- blockers = passed_pawn_mask(loserSide, s) & pos.pieces(winnerSide, PAWN);
-
- assert(blockers);
-
- // How many plies does it take to remove all the blocking pawns?
- while (blockers)
- {
- blockSq = pop_lsb(&blockers);
- movesToGo = 256;
-
- // Check pawns that can give support to overcome obstacle, for instance
- // black pawns: a4, b4 white: b2 then pawn in b4 is giving support.
- if (!opposed)
- {
- b2 = supporters & in_front_bb(winnerSide, blockSq + pawn_push(winnerSide));
-
- while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
- {
- d = square_distance(blockSq, pop_lsb(&b2)) - 2;
- movesToGo = std::min(movesToGo, d);
- }
- }
-
- // Check pawns that can be sacrificed against the blocking pawn
- b2 = attack_span_mask(winnerSide, blockSq) & candidates & ~(1ULL << s);
-
- while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
- {
- d = square_distance(blockSq, pop_lsb(&b2)) - 2;
- movesToGo = std::min(movesToGo, d);
- }
-
- // If obstacle can be destroyed with an immediate pawn exchange / sacrifice,
- // it's not a real obstacle and we have nothing to add to pliesToGo.
- if (movesToGo <= 0)
- continue;
-
- // Plies needed to sacrifice against all the blocking pawns
- sacptg += movesToGo * 2;
- blockersCount++;
-
- // Plies needed for the king to capture all the blocking pawns
- d = square_distance(pos.king_square(loserSide), blockSq);
- minKingDist = std::min(minKingDist, d);
- kingptg = (minKingDist + blockersCount) * 2;
- }
-
- // Check if pawn sacrifice plan _may_ save the day
- if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg)
- return SCORE_ZERO;
-
- // Check if king capture plan _may_ save the day (contains some false positives)
- if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg)
- return SCORE_ZERO;
- }
-
- // Winning pawn is unstoppable and will promote as first, return big score
- Score score = make_score(0, (Value) 1280 - 32 * pliesToQueen[winnerSide]);
- return winnerSide == WHITE ? score : -score;
+ return Unstoppable * int(relative_rank(us, frontmost_sq(us, b)));
}
// twice. Finally, the space bonus is scaled by a weight taken from the
// material hash table. The aim is to improve play on game opening.
template<Color Us>
- int evaluate_space(const Position& pos, EvalInfo& ei) {
+ int evaluate_space(const Position& pos, const EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
}
- // interpolate() interpolates between a middle game and an endgame score,
+ // interpolate() interpolates between a middlegame and an endgame score,
// based on game phase. It also scales the return value by a ScaleFactor array.
Value interpolate(const Score& v, Phase ph, ScaleFactor sf) {
assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
- int ev = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
- int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128;
- return Value((result + GrainSize / 2) & ~(GrainSize - 1));
+ int e = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
+ int r = (mg_value(v) * int(ph) + e * int(PHASE_MIDGAME - ph)) / PHASE_MIDGAME;
+ return Value((r / GrainSize) * GrainSize); // Sign independent
}
// apply_weight() weights score v by score w trying to prevent overflow
}
- // A couple of little helpers used by tracing code, to_cp() converts a value to
- // a double in centipawns scale, trace_add() stores white and black scores.
+ // Tracing functions definitions
double to_cp(Value v) { return double(v) / double(PawnValueMg); }
- void trace_add(int idx, Score wScore, Score bScore) {
+ void Tracing::add(int idx, Score wScore, Score bScore) {
- TracedScores[WHITE][idx] = wScore;
- TracedScores[BLACK][idx] = bScore;
+ scores[WHITE][idx] = wScore;
+ scores[BLACK][idx] = bScore;
}
+ void Tracing::row(const char* name, int idx) {
- // trace_row() is an helper function used by tracing code to register the
- // values of a single evaluation term.
-
- void trace_row(const char* name, int idx) {
-
- Score wScore = TracedScores[WHITE][idx];
- Score bScore = TracedScores[BLACK][idx];
+ Score wScore = scores[WHITE][idx];
+ Score bScore = scores[BLACK][idx];
switch (idx) {
- case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL:
- TraceStream << std::setw(20) << name << " | --- --- | --- --- | "
- << std::setw(6) << to_cp(mg_value(wScore)) << " "
- << std::setw(6) << to_cp(eg_value(wScore)) << " \n";
+ case PST: case IMBALANCE: case PAWN: case TOTAL:
+ stream << std::setw(20) << name << " | --- --- | --- --- | "
+ << std::setw(6) << to_cp(mg_value(wScore)) << " "
+ << std::setw(6) << to_cp(eg_value(wScore)) << " \n";
break;
default:
- TraceStream << std::setw(20) << name << " | " << std::noshowpos
- << std::setw(5) << to_cp(mg_value(wScore)) << " "
- << std::setw(5) << to_cp(eg_value(wScore)) << " | "
- << std::setw(5) << to_cp(mg_value(bScore)) << " "
- << std::setw(5) << to_cp(eg_value(bScore)) << " | "
- << std::showpos
- << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " "
- << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n";
+ stream << std::setw(20) << name << " | " << std::noshowpos
+ << std::setw(5) << to_cp(mg_value(wScore)) << " "
+ << std::setw(5) << to_cp(eg_value(wScore)) << " | "
+ << std::setw(5) << to_cp(mg_value(bScore)) << " "
+ << std::setw(5) << to_cp(eg_value(bScore)) << " | "
+ << std::showpos
+ << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " "
+ << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n";
}
}
+
+ std::string Tracing::do_trace(const Position& pos) {
+
+ stream.str("");
+ stream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
+ std::memset(scores, 0, 2 * (TOTAL + 1) * sizeof(Score));
+
+ do_evaluate<true>(pos);
+
+ std::string totals = stream.str();
+ stream.str("");
+
+ stream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
+ << " | MG EG | MG EG | MG EG \n"
+ << "---------------------+-------------+-------------+---------------\n";
+
+ row("Material, PST, Tempo", PST);
+ row("Material imbalance", IMBALANCE);
+ row("Pawns", PAWN);
+ row("Knights", KNIGHT);
+ row("Bishops", BISHOP);
+ row("Rooks", ROOK);
+ row("Queens", QUEEN);
+ row("Mobility", MOBILITY);
+ row("King safety", KING);
+ row("Threats", THREAT);
+ row("Passed pawns", PASSED);
+ row("Space", SPACE);
+
+ stream << "---------------------+-------------+-------------+---------------\n";
+ row("Total", TOTAL);
+ stream << totals;
+
+ return stream.str();
+ }
}
projects / stockfish / blobdiff