/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2012 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
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-
-////
-//// Includes
-////
-
#include <cassert>
+#include <iomanip>
+#include <sstream>
+#include <algorithm>
#include "bitcount.h"
#include "evaluate.h"
#include "thread.h"
#include "ucioption.h"
-
-////
-//// Local definitions
-////
-
namespace {
// Struct EvalInfo contains various information computed and collected
// by the evaluation functions.
struct EvalInfo {
- // Pointer to pawn hash table entry
+ // Pointers to material and pawn hash table entries
+ MaterialInfo* mi;
PawnInfo* pi;
// attackedBy[color][piece type] is a bitboard representing all squares
// all squares attacked by the given color.
Bitboard attackedBy[2][8];
- // kingZone[color] is the zone around the enemy king which is considered
+ // kingRing[color] is the zone around the king which is considered
// by the king safety evaluation. This consists of the squares directly
// adjacent to the king, and the three (or two, for a king on an edge file)
// squares two ranks in front of the king. For instance, if black's king
- // is on g8, kingZone[WHITE] is a bitboard containing the squares f8, h8,
+ // is on g8, kingRing[BLACK] is a bitboard containing the squares f8, h8,
// f7, g7, h7, f6, g6 and h6.
- Bitboard kingZone[2];
+ Bitboard kingRing[2];
// kingAttackersCount[color] is the number of pieces of the given color
- // which attack a square in the kingZone of the enemy king.
+ // which attack a square in the kingRing of the enemy king.
int kingAttackersCount[2];
// kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
- // given color which attack a square in the kingZone of the enemy king. The
+ // given color which attack a square in the kingRing of the enemy king. The
// weights of the individual piece types are given by the variables
// QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
// KnightAttackWeight in evaluate.cpp
int kingAdjacentZoneAttacksCount[2];
};
- const int Sign[2] = { 1, -1 };
-
// Evaluation grain size, must be a power of 2
const int GrainSize = 8;
// Evaluation weights, initialized from UCI options
- enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem };
+ enum { Mobility, PassedPawns, Space, KingDangerUs, KingDangerThem };
Score Weights[6];
typedef Value V;
//
// Values modified by Joona Kiiski
const Score WeightsInternal[] = {
- S(248, 271), S(233, 201), S(252, 259), S(46, 0), S(247, 0), S(259, 0)
+ S(252, 344), S(216, 266), S(46, 0), S(247, 0), S(259, 0)
};
// MobilityBonus[PieceType][attacked] contains mobility bonuses for middle and
V(0), V(0), V(4), V(8), V(8), V(4), V(0), V(0),
V(0), V(4),V(17),V(26),V(26),V(17), V(4), V(0),
V(0), V(8),V(26),V(35),V(35),V(26), V(8), V(0),
- V(0), V(4),V(17),V(17),V(17),V(17), V(4), V(0),
- V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
- V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) },
+ V(0), V(4),V(17),V(17),V(17),V(17), V(4), V(0) },
{
V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Bishops
V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0),
V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0),
V(0),V(10),V(21),V(21),V(21),V(21),V(10), V(0),
- V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0),
- V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
- V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) }
+ V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0) }
};
// ThreatBonus[attacking][attacked] contains threat bonuses according to
{ S(0, 0), S(15, 39), S(15, 39), S(15, 39), S(15, 39), S( 0, 0) } // QUEEN
};
- // ThreatedByPawnPenalty[PieceType] contains a penalty according to which
+ // ThreatenedByPawnPenalty[PieceType] contains a penalty according to which
// piece type is attacked by an enemy pawn.
- const Score ThreatedByPawnPenalty[] = {
+ const Score ThreatenedByPawnPenalty[] = {
S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
};
const Score QueenOn7thBonus = make_score(27, 54);
// Rooks on open files (modified by Joona Kiiski)
- const Score RookOpenFileBonus = make_score(43, 43);
- const Score RookHalfOpenFileBonus = make_score(19, 19);
+ const Score RookOpenFileBonus = make_score(43, 21);
+ const Score RookHalfOpenFileBonus = make_score(19, 10);
// Penalty for rooks trapped inside a friendly king which has lost the
// right to castle.
const Value TrappedRookPenalty = Value(180);
+ // 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(100, 100);
+
+ // Penalty for BNR that is not defended by anything
+ const Score UndefendedPiecePenalty = make_score(25, 10);
+
// 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
// based on how many squares inside this area are safe and available for
// friendly minor pieces.
- const Bitboard SpaceMask[2] = {
+ 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),
const int KingAttackWeights[] = { 0, 0, 2, 2, 3, 5 };
// Bonuses for enemy's safe checks
- const int QueenContactCheckBonus = 3;
- const int QueenCheckBonus = 2;
- const int RookCheckBonus = 1;
+ const int QueenContactCheckBonus = 6;
+ const int RookContactCheckBonus = 4;
+ const int QueenCheckBonus = 3;
+ const int RookCheckBonus = 2;
const int BishopCheckBonus = 1;
const int KnightCheckBonus = 1;
// weighted scores, indexed by color and by a calculated integer number.
Score KingDangerTable[2][128];
- // Pawn and material hash tables, indexed by the current thread id.
- // Note that they will be initialized at 0 being global variables.
- MaterialInfoTable* MaterialTable[MAX_THREADS];
- PawnInfoTable* PawnTable[MAX_THREADS];
+ // TracedTerms[Color][PieceType || TracedType] contains a breakdown of the
+ // evaluation terms, used when tracing.
+ Score TracedScores[2][16];
+ std::stringstream TraceStream;
+
+ enum TracedType {
+ PST = 8, IMBALANCE = 9, MOBILITY = 10, THREAT = 11,
+ PASSED = 12, UNSTOPPABLE = 13, SPACE = 14, TOTAL = 15
+ };
// Function prototypes
- template<bool HasPopCnt>
- Value do_evaluate(const Position& pos, Value margins[]);
+ template<bool Trace>
+ Value do_evaluate(const Position& pos, Value& margin);
- template<Color Us, bool HasPopCnt>
- void init_attack_tables(const Position& pos, EvalInfo& ei);
+ template<Color Us>
+ void init_eval_info(const Position& pos, EvalInfo& ei);
- template<Color Us, bool HasPopCnt>
+ template<Color Us, bool Trace>
Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility);
- template<Color Us, bool HasPopCnt>
+ template<Color Us, bool Trace>
Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]);
template<Color Us>
Score evaluate_threats(const Position& pos, EvalInfo& ei);
- template<Color Us, bool HasPopCnt>
+ template<Color Us>
int evaluate_space(const Position& pos, EvalInfo& ei);
template<Color Us>
Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
+ Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
+
inline Score apply_weight(Score v, Score weight);
- Value scale_by_game_phase(const Score& v, Phase ph, const ScaleFactor sf[]);
+ Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf);
Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
- void init_safety();
+ 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);
}
-////
-//// Functions
-////
+namespace Eval {
+ Color RootColor;
-/// Prefetches in pawn hash tables
+ /// evaluate() is the main evaluation function. It always computes two
+ /// values, an endgame score and a middle game score, and interpolates
+ /// between them based on the remaining material.
-void prefetchPawn(Key key, int threadID) {
+ Value evaluate(const Position& pos, Value& margin) {
+ return do_evaluate<false>(pos, margin);
+ }
- PawnTable[threadID]->prefetch(key);
-}
-/// evaluate() is the main evaluation function. It always computes two
-/// values, an endgame score and a middle game score, and interpolates
-/// between them based on the remaining material.
-Value evaluate(const Position& pos, Value margins[]) {
+ /// init() computes evaluation weights from the corresponding UCI parameters
+ /// and setup king tables.
+
+ void init() {
+
+ Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
+ Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
+ Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
+ Weights[KingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
+ Weights[KingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
+
+ // King safety is asymmetrical. Our king danger level is weighted by
+ // "Cowardice" UCI parameter, instead the opponent one by "Aggressiveness".
+ // If running in analysis mode, make sure we use symmetrical king safety. We
+ // do this by replacing both Weights[kingDangerUs] and Weights[kingDangerThem]
+ // by their average.
+ if (Options["UCI_AnalyseMode"])
+ Weights[KingDangerUs] = Weights[KingDangerThem] = (Weights[KingDangerUs] + Weights[KingDangerThem]) / 2;
+
+ const int MaxSlope = 30;
+ const int Peak = 1280;
+
+ 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]);
+ }
+ }
+
+
+ /// 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;
+
+ 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
- return CpuHasPOPCNT ? do_evaluate<true>(pos, margins)
- : do_evaluate<false>(pos, margins);
-}
namespace {
-template<bool HasPopCnt>
-Value do_evaluate(const Position& pos, Value margins[]) {
+template<bool Trace>
+Value do_evaluate(const Position& pos, Value& margin) {
EvalInfo ei;
- ScaleFactor factor[2];
- Score w_mob, b_mob;
+ Value margins[2];
+ Score score, mobilityWhite, mobilityBlack;
- assert(pos.is_ok());
assert(pos.thread() >= 0 && pos.thread() < MAX_THREADS);
- assert(!pos.is_check());
+ assert(!pos.in_check());
- // Initialize by reading the incrementally updated scores included in the
- // position object (material + piece square tables).
- Score value = pos.value();
+ // Initialize score by reading the incrementally updated scores included
+ // in the position object (material + piece square tables).
+ score = pos.value();
- // margins[color] stores the uncertainty estimation of position's evaluation
- // and typically is used by the search for pruning decisions.
+ // 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;
// Probe the material hash table
- MaterialInfo* mi = MaterialTable[pos.thread()]->get_material_info(pos);
- value += mi->material_value();
+ ei.mi = Threads[pos.thread()].materialTable.material_info(pos);
+ score += ei.mi->material_value();
// If we have a specialized evaluation function for the current material
// configuration, call it and return.
- if (mi->specialized_eval_exists())
- return mi->evaluate(pos);
-
- // After get_material_info() call that modifies them
- factor[WHITE] = mi->scale_factor(pos, WHITE);
- factor[BLACK] = mi->scale_factor(pos, BLACK);
+ if (ei.mi->specialized_eval_exists())
+ {
+ margin = VALUE_ZERO;
+ return ei.mi->evaluate(pos);
+ }
// Probe the pawn hash table
- ei.pi = PawnTable[pos.thread()]->get_pawn_info(pos);
- value += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
+ ei.pi = Threads[pos.thread()].pawnTable.pawn_info(pos);
+ score += ei.pi->pawns_value();
- // Initialize attack bitboards with pawns evaluation
- init_attack_tables<WHITE, HasPopCnt>(pos, ei);
- init_attack_tables<BLACK, HasPopCnt>(pos, ei);
+ // Initialize attack and king safety bitboards
+ init_eval_info<WHITE>(pos, ei);
+ init_eval_info<BLACK>(pos, ei);
// Evaluate pieces and mobility
- value += evaluate_pieces_of_color<WHITE, HasPopCnt>(pos, ei, w_mob)
- - evaluate_pieces_of_color<BLACK, HasPopCnt>(pos, ei, b_mob);
+ score += evaluate_pieces_of_color<WHITE, Trace>(pos, ei, mobilityWhite)
+ - evaluate_pieces_of_color<BLACK, Trace>(pos, ei, mobilityBlack);
- value += apply_weight(w_mob - b_mob, Weights[Mobility]);
+ score += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
- // Evaluate kings after all other pieces for both sides, because we
- // need complete attack information for all pieces when computing
- // the king safety evaluation.
- value += evaluate_king<WHITE, HasPopCnt>(pos, ei, margins)
- - evaluate_king<BLACK, HasPopCnt>(pos, ei, margins);
+ // 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);
- // Evaluate tactical threats, we need full attack info including king
- value += evaluate_threats<WHITE>(pos, ei)
+ // Evaluate tactical threats, we need full attack information including king
+ score += evaluate_threats<WHITE>(pos, ei)
- evaluate_threats<BLACK>(pos, ei);
- // Evaluate passed pawns, we need full attack info including king
- value += evaluate_passed_pawns<WHITE>(pos, ei)
+ // Evaluate passed pawns, we need full attack information including king
+ score += evaluate_passed_pawns<WHITE>(pos, ei)
- evaluate_passed_pawns<BLACK>(pos, ei);
- Phase phase = mi->game_phase();
+ // If one side has only a king, check whether exists any unstoppable passed pawn
+ if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
+ score += evaluate_unstoppable_pawns(pos, ei);
- // Middle-game specific evaluation terms
- if (phase > PHASE_ENDGAME)
+ // Evaluate space for both sides, only in middle-game.
+ if (ei.mi->space_weight())
{
- // Evaluate pawn storms in positions with opposite castling
- if ( square_file(pos.king_square(WHITE)) >= FILE_E
- && square_file(pos.king_square(BLACK)) <= FILE_D)
-
- value += make_score(ei.pi->queenside_storm_value(WHITE) - ei.pi->kingside_storm_value(BLACK), 0);
-
- else if ( square_file(pos.king_square(WHITE)) <= FILE_D
- && square_file(pos.king_square(BLACK)) >= FILE_E)
-
- value += make_score(ei.pi->kingside_storm_value(WHITE) - ei.pi->queenside_storm_value(BLACK), 0);
-
- // Evaluate space for both sides
- if (mi->space_weight() > 0)
- {
- int s = evaluate_space<WHITE, HasPopCnt>(pos, ei) - evaluate_space<BLACK, HasPopCnt>(pos, ei);
- value += apply_weight(make_score(s * mi->space_weight(), 0), Weights[Space]);
- }
+ 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]);
}
+ // Scale winning side if position is more drawish that what it appears
+ ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE)
+ : ei.mi->scale_factor(pos, BLACK);
+
// If we don't already have an unusual scale factor, check for opposite
- // colored bishop endgames, and use a lower scale for those
- if ( phase < PHASE_MIDGAME
+ // colored bishop endgames, and use a lower scale for those.
+ if ( ei.mi->game_phase() < PHASE_MIDGAME
&& pos.opposite_colored_bishops()
- && ( (factor[WHITE] == SCALE_FACTOR_NORMAL && eg_value(value) > VALUE_ZERO)
- || (factor[BLACK] == SCALE_FACTOR_NORMAL && eg_value(value) < VALUE_ZERO)))
+ && sf == SCALE_FACTOR_NORMAL)
{
- ScaleFactor sf;
-
// Only the two bishops ?
if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
&& pos.non_pawn_material(BLACK) == BishopValueMidgame)
// Endgame with opposite-colored bishops, but also other pieces. Still
// a bit drawish, but not as drawish as with only the two bishops.
sf = ScaleFactor(50);
-
- if (factor[WHITE] == SCALE_FACTOR_NORMAL)
- factor[WHITE] = sf;
- if (factor[BLACK] == SCALE_FACTOR_NORMAL)
- factor[BLACK] = sf;
}
// Interpolate between the middle game and the endgame score
- return Sign[pos.side_to_move()] * scale_by_game_phase(value, phase, factor);
-}
-
-} // namespace
-
-/// init_eval() initializes various tables used by the evaluation function
-
-void init_eval(int threads) {
-
- assert(threads <= MAX_THREADS);
-
- for (int i = 0; i < MAX_THREADS; i++)
- {
- if (i >= threads)
- {
- delete PawnTable[i];
- delete MaterialTable[i];
- PawnTable[i] = NULL;
- MaterialTable[i] = NULL;
- continue;
- }
- if (!PawnTable[i])
- PawnTable[i] = new PawnInfoTable();
- if (!MaterialTable[i])
- MaterialTable[i] = new MaterialInfoTable();
- }
-}
-
+ margin = margins[pos.side_to_move()];
+ Value v = scale_by_game_phase(score, ei.mi->game_phase(), sf);
-/// quit_eval() releases heap-allocated memory at program termination
-
-void quit_eval() {
-
- for (int i = 0; i < MAX_THREADS; i++)
+ // In case of tracing add all single evaluation contributions for both white and black
+ if (Trace)
{
- delete PawnTable[i];
- delete MaterialTable[i];
- PawnTable[i] = NULL;
- MaterialTable[i] = NULL;
+ trace_add(PST, pos.value());
+ trace_add(IMBALANCE, ei.mi->material_value());
+ trace_add(PAWN, ei.pi->pawns_value());
+ trace_add(MOBILITY, apply_weight(mobilityWhite, Weights[Mobility]), apply_weight(mobilityBlack, Weights[Mobility]));
+ trace_add(THREAT, evaluate_threats<WHITE>(pos, ei), evaluate_threats<BLACK>(pos, ei));
+ trace_add(PASSED, evaluate_passed_pawns<WHITE>(pos, ei), evaluate_passed_pawns<BLACK>(pos, ei));
+ 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);
}
-}
-
-
-/// read_weights() reads evaluation weights from the corresponding UCI parameters
-
-void read_weights(Color us) {
- // King safety is asymmetrical. Our king danger level is weighted by
- // "Cowardice" UCI parameter, instead the opponent one by "Aggressiveness".
- const int kingDangerUs = (us == WHITE ? KingDangerUs : KingDangerThem);
- const int kingDangerThem = (us == WHITE ? KingDangerThem : KingDangerUs);
-
- Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
- Weights[PawnStructure] = weight_option("Pawn Structure (Middle Game)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
- Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
- Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
- Weights[kingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
- Weights[kingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
-
- // If running in analysis mode, make sure we use symmetrical king safety. We do this
- // by replacing both Weights[kingDangerUs] and Weights[kingDangerThem] by their average.
- if (get_option_value_bool("UCI_AnalyseMode"))
- Weights[kingDangerUs] = Weights[kingDangerThem] = (Weights[kingDangerUs] + Weights[kingDangerThem]) / 2;
-
- init_safety();
+ return pos.side_to_move() == WHITE ? v : -v;
}
-namespace {
-
- // init_attack_tables() initializes king bitboards for both sides adding
- // pawn attacks. To be done before other evaluations.
+ // init_eval_info() initializes king bitboards for given color adding
+ // pawn attacks. To be done at the beginning of the evaluation.
- template<Color Us, bool HasPopCnt>
- void init_attack_tables(const Position& pos, EvalInfo& ei) {
+ template<Color Us>
+ void init_eval_info(const Position& pos, EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
- ei.kingZone[Us] = (b | (Us == WHITE ? b >> 8 : b << 8));
ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
- b &= ei.attackedBy[Us][PAWN];
- ei.kingAttackersCount[Us] = b ? count_1s_max_15<HasPopCnt>(b) / 2 : 0;
- ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
+
+ // Init king safety tables only if we are going to use them
+ if ( pos.piece_count(Us, QUEEN)
+ && pos.non_pawn_material(Us) >= QueenValueMidgame + RookValueMidgame)
+ {
+ ei.kingRing[Them] = (b | (Us == WHITE ? b >> 8 : b << 8));
+ b &= ei.attackedBy[Us][PAWN];
+ ei.kingAttackersCount[Us] = b ? popcount<Max15>(b) / 2 : 0;
+ ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
+ } else
+ ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0;
}
Value bonus = OutpostBonus[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
- if (bonus && bit_is_set(ei.attackedBy[Us][PAWN], s))
+ // no minor piece which can exchange the outpost piece.
+ if (bonus && (ei.attackedBy[Us][PAWN] & s))
{
- if ( pos.pieces(KNIGHT, Them) == EmptyBoardBB
- && (SquaresByColorBB[square_color(s)] & pos.pieces(BISHOP, Them)) == EmptyBoardBB)
+ if ( !pos.pieces(KNIGHT, Them)
+ && !(same_color_squares(s) & pos.pieces(BISHOP, Them)))
bonus += bonus + bonus / 2;
else
bonus += bonus / 2;
// evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
- template<PieceType Piece, Color Us, bool HasPopCnt>
- Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard no_mob_area) {
+ template<PieceType Piece, Color Us, bool Trace>
+ Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
Bitboard b;
Square s, ksq;
int mob;
File f;
- Score bonus = SCORE_ZERO;
+ Score score = SCORE_ZERO;
const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Square* ptr = pos.piece_list_begin(Us, Piece);
+ const Square* pl = pos.piece_list(Us, Piece);
ei.attackedBy[Us][Piece] = 0;
- while ((s = *ptr++) != SQ_NONE)
+ while ((s = *pl++) != SQ_NONE)
{
// Find attacked squares, including x-ray attacks for bishops and rooks
if (Piece == KNIGHT || Piece == QUEEN)
b = pos.attacks_from<Piece>(s);
else if (Piece == BISHOP)
- b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
+ b = attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(QUEEN, Us));
else if (Piece == ROOK)
- b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
+ b = attacks_bb<ROOK>(s, pos.pieces() ^ pos.pieces(ROOK, QUEEN, Us));
else
assert(false);
- // Update attack info
ei.attackedBy[Us][Piece] |= b;
- // King attacks
- if (b & ei.kingZone[Us])
+ if (b & ei.kingRing[Them])
{
ei.kingAttackersCount[Us]++;
ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
Bitboard bb = (b & ei.attackedBy[Them][KING]);
if (bb)
- ei.kingAdjacentZoneAttacksCount[Us] += count_1s_max_15<HasPopCnt>(bb);
+ ei.kingAdjacentZoneAttacksCount[Us] += popcount<Max15>(bb);
}
- // Mobility
- mob = (Piece != QUEEN ? count_1s_max_15<HasPopCnt>(b & no_mob_area)
- : count_1s<HasPopCnt>(b & no_mob_area));
+ mob = (Piece != QUEEN ? popcount<Max15>(b & mobilityArea)
+ : popcount<Full >(b & mobilityArea));
mobility += MobilityBonus[Piece][mob];
+ // Add a bonus if a slider is pinning an enemy piece
+ if ( (Piece == BISHOP || Piece == ROOK || Piece == QUEEN)
+ && (PseudoAttacks[Piece][pos.king_square(Them)] & s))
+ {
+ b = BetweenBB[s][pos.king_square(Them)] & pos.pieces();
+
+ assert(b);
+
+ if (single_bit(b) && (b & pos.pieces(Them)))
+ score += ThreatBonus[Piece][type_of(pos.piece_on(first_1(b)))];
+ }
+
// Decrease score if we are attacked by an enemy pawn. Remaining part
// of threat evaluation must be done later when we have full attack info.
- if (bit_is_set(ei.attackedBy[Them][PAWN], s))
- bonus -= ThreatedByPawnPenalty[Piece];
+ if (ei.attackedBy[Them][PAWN] & s)
+ score -= ThreatenedByPawnPenalty[Piece];
// Bishop and knight outposts squares
- if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Us))
- bonus += evaluate_outposts<Piece, Us>(pos, ei, s);
+ if ( (Piece == BISHOP || Piece == KNIGHT)
+ && !(pos.pieces(PAWN, Them) & attack_span_mask(Us, s)))
+ score += evaluate_outposts<Piece, Us>(pos, ei, s);
// Queen or rook on 7th rank
if ( (Piece == ROOK || Piece == QUEEN)
&& relative_rank(Us, s) == RANK_7
&& relative_rank(Us, pos.king_square(Them)) == RANK_8)
{
- bonus += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
+ score += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
+ }
+
+ // Special extra evaluation for bishops
+ if (Piece == BISHOP && pos.is_chess960())
+ {
+ // 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 (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1))
+ {
+ Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
+ if (pos.piece_on(s + d) == make_piece(Us, PAWN))
+ {
+ if (!pos.square_is_empty(s + d + pawn_push(Us)))
+ score -= 2*TrappedBishopA1H1Penalty;
+ else if (pos.piece_on(s + 2*d) == make_piece(Us, PAWN))
+ score -= TrappedBishopA1H1Penalty;
+ else
+ score -= TrappedBishopA1H1Penalty / 2;
+ }
+ }
}
// Special extra evaluation for rooks
if (Piece == ROOK)
{
// Open and half-open files
- f = square_file(s);
+ f = file_of(s);
if (ei.pi->file_is_half_open(Us, f))
{
if (ei.pi->file_is_half_open(Them, f))
- bonus += RookOpenFileBonus;
+ score += RookOpenFileBonus;
else
- bonus += RookHalfOpenFileBonus;
+ score += RookHalfOpenFileBonus;
}
// Penalize rooks which are trapped inside a king. Penalize more if
ksq = pos.king_square(Us);
- if ( square_file(ksq) >= FILE_E
- && square_file(s) > square_file(ksq)
- && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
+ if ( file_of(ksq) >= FILE_E
+ && file_of(s) > file_of(ksq)
+ && (relative_rank(Us, ksq) == RANK_1 || rank_of(ksq) == rank_of(s)))
{
// Is there a half-open file between the king and the edge of the board?
- if (!ei.pi->has_open_file_to_right(Us, square_file(ksq)))
- bonus -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
+ if (!ei.pi->has_open_file_to_right(Us, file_of(ksq)))
+ score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
: (TrappedRookPenalty - mob * 16), 0);
}
- else if ( square_file(ksq) <= FILE_D
- && square_file(s) < square_file(ksq)
- && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
+ else if ( file_of(ksq) <= FILE_D
+ && file_of(s) < file_of(ksq)
+ && (relative_rank(Us, ksq) == RANK_1 || rank_of(ksq) == rank_of(s)))
{
// Is there a half-open file between the king and the edge of the board?
- if (!ei.pi->has_open_file_to_left(Us, square_file(ksq)))
- bonus -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
+ if (!ei.pi->has_open_file_to_left(Us, file_of(ksq)))
+ score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
: (TrappedRookPenalty - mob * 16), 0);
}
}
}
- return bonus;
+
+ if (Trace)
+ TracedScores[Us][Piece] = score;
+
+ return score;
}
const Color Them = (Us == WHITE ? BLACK : WHITE);
Bitboard b;
- Score bonus = SCORE_ZERO;
+ Score score = SCORE_ZERO;
+
+ // Undefended pieces get penalized even if not under attack
+ Bitboard undefended = pos.pieces(Them) & ~ei.attackedBy[Them][0];
+ const Bitboard undefendedMinors = undefended & (pos.pieces(BISHOP) | pos.pieces(KNIGHT));
+
+ if (undefendedMinors)
+ score += single_bit(undefendedMinors) ? UndefendedPiecePenalty
+ : UndefendedPiecePenalty * 2;
+ if (undefended & pos.pieces(ROOK))
+ score += UndefendedPiecePenalty;
// Enemy pieces not defended by a pawn and under our attack
- Bitboard weakEnemies = pos.pieces_of_color(Them)
+ Bitboard weakEnemies = pos.pieces(Them)
& ~ei.attackedBy[Them][PAWN]
& ei.attackedBy[Us][0];
if (!weakEnemies)
- return SCORE_ZERO;
+ return score;
- // Add bonus according to type of attacked enemy pieces and to the
+ // 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 special handled in king evaluation.
+ // considered because are already handled in king evaluation.
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))
- bonus += ThreatBonus[pt1][pt2];
+ score += ThreatBonus[pt1][pt2];
}
- return bonus;
+ return score;
}
// evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
// pieces of a given color.
- template<Color Us, bool HasPopCnt>
+ template<Color Us, bool Trace>
Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
- Score bonus = SCORE_ZERO;
-
- mobility = SCORE_ZERO;
+ Score score = mobility = SCORE_ZERO;
// Do not include in mobility squares protected by enemy pawns or occupied by our pieces
- const Bitboard no_mob_area = ~(ei.attackedBy[Them][PAWN] | pos.pieces_of_color(Us));
+ const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces(Us));
- bonus += evaluate_pieces<KNIGHT, Us, HasPopCnt>(pos, ei, mobility, no_mob_area);
- bonus += evaluate_pieces<BISHOP, Us, HasPopCnt>(pos, ei, mobility, no_mob_area);
- bonus += evaluate_pieces<ROOK, Us, HasPopCnt>(pos, ei, mobility, no_mob_area);
- bonus += evaluate_pieces<QUEEN, Us, HasPopCnt>(pos, ei, mobility, no_mob_area);
+ 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);
// Sum up all attacked squares
ei.attackedBy[Us][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
| ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
| ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
- return bonus;
+ return score;
}
// evaluate_king<>() assigns bonuses and penalties to a king of a given color
- template<Color Us, bool HasPopCnt>
+ template<Color Us, bool Trace>
Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
Bitboard undefended, b, b1, b2, safe;
- bool sente;
int attackUnits;
const Square ksq = pos.king_square(Us);
// King shelter
- Score bonus = ei.pi->king_shelter(pos, Us, ksq);
+ Score score = ei.pi->king_shelter<Us>(pos, ksq);
// King safety. This is quite complicated, and is almost certainly far
// from optimally tuned.
- if ( pos.piece_count(Them, QUEEN) >= 1
- && ei.kingAttackersCount[Them] >= 2
- && pos.non_pawn_material(Them) >= QueenValueMidgame + RookValueMidgame
+ if ( ei.kingAttackersCount[Them] >= 2
&& ei.kingAdjacentZoneAttacksCount[Them])
{
- // Is it the attackers turn to move?
- sente = (Them == pos.side_to_move());
-
// Find the attacked squares around the king which has no defenders
// apart from the king itself
undefended = ei.attackedBy[Them][0] & ei.attackedBy[Us][KING];
// 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 = Min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
- + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + count_1s_max_15<HasPopCnt>(undefended))
+ attackUnits = std::min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
+ + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount<Max15>(undefended))
+ InitKingDanger[relative_square(Us, ksq)]
- - mg_value(ei.pi->king_shelter(pos, Us, ksq)) / 32;
+ - mg_value(ei.pi->king_shelter<Us>(pos, ksq)) / 32;
// Analyse enemy's safe queen contact checks. First find undefended
// squares around the king attacked by enemy queen...
- b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces_of_color(Them);
+ b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
if (b)
{
// ...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 * count_1s_max_15<HasPopCnt>(b) * (sente ? 2 : 1);
+ attackUnits += QueenContactCheckBonus
+ * 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...
+ b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
+
+ // Consider only squares where the enemy rook gives check
+ b &= PseudoAttacks[ROOK][ksq];
+
+ if (b)
+ {
+ // ...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
+ * popcount<Max15>(b)
+ * (Them == pos.side_to_move() ? 2 : 1);
}
// Analyse enemy's safe distance checks for sliders and knights
- safe = ~(pos.pieces_of_color(Them) | ei.attackedBy[Us][0]);
+ safe = ~(pos.pieces(Them) | ei.attackedBy[Us][0]);
b1 = pos.attacks_from<ROOK>(ksq) & safe;
b2 = pos.attacks_from<BISHOP>(ksq) & safe;
// Enemy queen safe checks
b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
if (b)
- attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b);
+ attackUnits += QueenCheckBonus * popcount<Max15>(b);
// Enemy rooks safe checks
b = b1 & ei.attackedBy[Them][ROOK];
if (b)
- attackUnits += RookCheckBonus * count_1s_max_15<HasPopCnt>(b);
+ attackUnits += RookCheckBonus * popcount<Max15>(b);
// Enemy bishops safe checks
b = b2 & ei.attackedBy[Them][BISHOP];
if (b)
- attackUnits += BishopCheckBonus * count_1s_max_15<HasPopCnt>(b);
+ attackUnits += BishopCheckBonus * popcount<Max15>(b);
// Enemy knights safe checks
b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
if (b)
- attackUnits += KnightCheckBonus * count_1s_max_15<HasPopCnt>(b);
+ attackUnits += KnightCheckBonus * popcount<Max15>(b);
// To index KingDangerTable[] attackUnits must be in [0, 99] range
- attackUnits = Min(99, Max(0, attackUnits));
+ 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.
- bonus -= KingDangerTable[Us][attackUnits];
- margins[Us] += mg_value(KingDangerTable[Us][attackUnits]);
+ score -= KingDangerTable[Us == Eval::RootColor][attackUnits];
+ margins[Us] += mg_value(KingDangerTable[Us == Eval::RootColor][attackUnits]);
}
- return bonus;
+
+ if (Trace)
+ TracedScores[Us][KING] = score;
+
+ return score;
}
const Color Them = (Us == WHITE ? BLACK : WHITE);
- Score bonus = SCORE_ZERO;
- Bitboard squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
- Bitboard b = ei.pi->passed_pawns(Us);
+ Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
+ Score score = SCORE_ZERO;
+
+ b = ei.pi->passed_pawns(Us);
if (!b)
return SCORE_ZERO;
assert(pos.pawn_is_passed(Us, s));
int r = int(relative_rank(Us, s) - RANK_2);
- int tr = r * (r - 1);
+ int rr = r * (r - 1);
// Base bonus based on rank
- Value mbonus = Value(20 * tr);
- Value ebonus = Value(10 + r * r * 10);
+ Value mbonus = Value(20 * rr);
+ Value ebonus = Value(10 * (rr + r + 1));
- if (tr)
+ if (rr)
{
Square blockSq = s + pawn_push(Us);
// Adjust bonus based on kings proximity
- ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 3 * tr);
- ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * 1 * tr);
- ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 6 * tr);
+ ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 5 * rr);
+ ebonus -= 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))
+ ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
// If the pawn is free to advance, increase bonus
if (pos.square_is_empty(blockSq))
// 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 ( (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them))
- && (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from<ROOK>(s)))
+ if ( (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them))
+ && (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from<ROOK>(s)))
unsafeSquares = squaresToQueen;
else
- unsafeSquares = squaresToQueen & (ei.attackedBy[Them][0] | pos.pieces_of_color(Them));
+ unsafeSquares = squaresToQueen & (ei.attackedBy[Them][0] | pos.pieces(Them));
// If there aren't enemy attacks or pieces along the path to queen give
// huge bonus. Even bigger if we protect the pawn's path.
if (!unsafeSquares)
- ebonus += Value(tr * (squaresToQueen == defendedSquares ? 17 : 15));
+ ebonus += Value(rr * (squaresToQueen == defendedSquares ? 17 : 15));
else
// OK, there are enemy attacks or pieces (but not pawns). Are those
// squares which are attacked by the enemy also attacked by us ?
// If yes, big bonus (but smaller than when there are no enemy attacks),
// if no, somewhat smaller bonus.
- ebonus += Value(tr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8));
-
- // At last, add a small bonus when there are no *friendly* pieces
- // in the pawn's path.
- if (!(squaresToQueen & pos.pieces_of_color(Us)))
- ebonus += Value(tr);
+ ebonus += Value(rr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8));
}
- } // tr != 0
+ } // rr != 0
// Increase the bonus if the passed pawn is supported by a friendly pawn
// on the same rank and a bit smaller if it's on the previous rank.
- supportingPawns = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
+ supportingPawns = pos.pieces(PAWN, Us) & adjacent_files_bb(file_of(s));
if (supportingPawns & rank_bb(s))
ebonus += Value(r * 20);
+
else if (supportingPawns & rank_bb(s - pawn_push(Us)))
ebonus += Value(r * 12);
// we try the following: Increase the value for rook pawns if the
// other side has no pieces apart from a knight, and decrease the
// value if the other side has a rook or queen.
- if (square_file(s) == FILE_A || square_file(s) == FILE_H)
+ if (file_of(s) == FILE_A || file_of(s) == FILE_H)
{
if (pos.non_pawn_material(Them) <= KnightValueMidgame)
ebonus += ebonus / 4;
else if (pos.pieces(ROOK, QUEEN, Them))
ebonus -= ebonus / 4;
}
- bonus += make_score(mbonus, ebonus);
+ score += make_score(mbonus, ebonus);
} while (b);
// Add the scores to the middle game and endgame eval
- return apply_weight(bonus, Weights[PassedPawns]);
+ 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_1st_bit(&b);
+ queeningSquare = relative_square(c, make_square(file_of(s), RANK_8));
+ queeningPath = squares_in_front_of(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][0] & 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.in_check());
+ assert((queeningPath & pos.pieces()) == (queeningPath & pos.pieces(c)));
+
+ // Add moves needed to free the path from friendly pieces and retest condition
+ movesToGo += popcount<Max15>(queeningPath & pos.pieces(c));
+
+ if (movesToGo >= oppMovesToGo && !pathDefended)
+ continue;
+
+ 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)
+ 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(PAWN, loserSide);
+
+ while (b)
+ {
+ s = pop_1st_bit(&b);
+
+ // Compute plies from queening
+ queeningSquare = relative_square(loserSide, make_square(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
+ || (squares_in_front_of(loserSide, s) & pos.pieces(PAWN, loserSide)))
+ 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_1st_bit(&b);
+ sacptg = blockersCount = 0;
+ minKingDist = kingptg = 256;
+
+ // Compute plies from queening
+ queeningSquare = relative_square(loserSide, make_square(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 = squares_in_front_of(loserSide, s) & pos.pieces(PAWN, winnerSide);
+ blockers = passed_pawn_mask(loserSide, s) & pos.pieces(PAWN, winnerSide);
+
+ assert(blockers);
+
+ // How many plies does it take to remove all the blocking pawns?
+ while (blockers)
+ {
+ blockSq = pop_1st_bit(&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_1st_bit(&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_1st_bit(&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) 0x500 - 0x20 * pliesToQueen[winnerSide]);
+ return winnerSide == WHITE ? score : -score;
}
// available for minor pieces on the central four files on ranks 2--4. Safe
// squares one, two or three squares behind a friendly pawn are counted
// twice. Finally, the space bonus is scaled by a weight taken from the
- // material hash table.
- template<Color Us, bool HasPopCnt>
+ // material hash table. The aim is to improve play on game opening.
+ template<Color Us>
int evaluate_space(const Position& pos, EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
// Find the safe squares for our pieces inside the area defined by
- // SpaceMask[us]. A square is unsafe if it is attacked by an enemy
+ // SpaceMask[]. A square is unsafe if it is attacked by an enemy
// pawn, or if it is undefended and attacked by an enemy piece.
Bitboard safe = SpaceMask[Us]
& ~pos.pieces(PAWN, Us)
behind |= (Us == WHITE ? behind >> 8 : behind << 8);
behind |= (Us == WHITE ? behind >> 16 : behind << 16);
- return count_1s_max_15<HasPopCnt>(safe) + count_1s_max_15<HasPopCnt>(behind & safe);
+ return popcount<Max15>(safe) + popcount<Max15>(behind & safe);
}
// apply_weight() applies an evaluation weight to a value trying to prevent overflow
inline Score apply_weight(Score v, Score w) {
- return make_score((int(mg_value(v)) * mg_value(w)) / 0x100, (int(eg_value(v)) * eg_value(w)) / 0x100);
+ return make_score((int(mg_value(v)) * mg_value(w)) / 0x100,
+ (int(eg_value(v)) * eg_value(w)) / 0x100);
}
// scale_by_game_phase() interpolates between a middle game and an endgame score,
// based on game phase. It also scales the return value by a ScaleFactor array.
- Value scale_by_game_phase(const Score& v, Phase ph, const ScaleFactor sf[]) {
+ Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf) {
assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
- Value eg = eg_value(v);
- ScaleFactor f = sf[eg > VALUE_ZERO ? WHITE : BLACK];
- Value ev = Value((eg * int(f)) / SCALE_FACTOR_NORMAL);
-
+ 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 - 1));
+ return Value((result + GrainSize / 2) & ~(GrainSize - 1));
}
Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
// Scale option value from 100 to 256
- int mg = get_option_value_int(mgOpt) * 256 / 100;
- int eg = get_option_value_int(egOpt) * 256 / 100;
+ int mg = Options[mgOpt] * 256 / 100;
+ int eg = Options[egOpt] * 256 / 100;
return apply_weight(make_score(mg, eg), internalWeight);
}
- // init_safety() initizes the king safety evaluation, based on UCI
- // parameters. It is called from read_weights().
- void init_safety() {
+ // 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.
- const Value MaxSlope = Value(30);
- const Value Peak = Value(1280);
- Value t[100];
+ double to_cp(Value v) { return double(v) / double(PawnValueMidgame); }
- // First setup the base table
- for (int i = 0; i < 100; i++)
- {
- t[i] = Value(int(0.4 * i * i));
+ void trace_add(int idx, Score wScore, Score bScore) {
- if (i > 0)
- t[i] = Min(t[i], t[i - 1] + MaxSlope);
+ TracedScores[WHITE][idx] = wScore;
+ TracedScores[BLACK][idx] = bScore;
+ }
- t[i] = Min(t[i], Peak);
- }
- // Then apply the weights and get the final KingDangerTable[] array
- for (Color c = WHITE; c <= BLACK; c++)
- for (int i = 0; i < 100; i++)
- KingDangerTable[c][i] = apply_weight(make_score(t[i], 0), Weights[KingDangerUs + c]);
+ // 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];
+
+ 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";
+ 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";
+ }
}
}
projects / stockfish / blobdiff