/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 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/>.
*/
+#include <algorithm>
#include <cassert>
+#include <cstring> // For std::memset
#include <iomanip>
#include <sstream>
-#include <algorithm>
#include "bitcount.h"
#include "evaluate.h"
#include "material.h"
#include "pawns.h"
-#include "thread.h"
-#include "ucioption.h"
namespace {
// kingAttackersWeight[color] is the sum of the "weight" of the pieces of 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
+ // weights of the individual piece types are given by the elements in the
+ // KingAttackWeights array.
int kingAttackersWeight[COLOR_NB];
- // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
- // directly adjacent to the king of the given color. Pieces which attack
- // more than one square are counted multiple times. For instance, if black's
- // king is on g8 and there's a white knight on g5, this knight adds
- // 2 to kingAdjacentZoneAttacksCount[BLACK].
+ // kingAdjacentZoneAttacksCount[color] is the number of attacks by the given
+ // color to squares directly adjacent to the enemy king. Pieces which attack
+ // more than one square are counted multiple times. For instance, if there is
+ // a white knight on g5 and black's king is on g8, this white knight adds 2
+ // to kingAdjacentZoneAttacksCount[WHITE].
int kingAdjacentZoneAttacksCount[COLOR_NB];
Bitboard pinnedPieces[COLOR_NB];
namespace Tracing {
enum Terms { // First 8 entries are for PieceType
- PST = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERMS_NB
+ MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERMS_NB
};
- Score terms[COLOR_NB][TERMS_NB];
+ Score scores[COLOR_NB][TERMS_NB];
EvalInfo ei;
ScaleFactor sf;
double to_cp(Value v);
- void add_term(int idx, Score term_w, Score term_b = SCORE_ZERO);
- void format_row(std::stringstream& ss, const char* name, int idx);
+ void write(int idx, Color c, Score s);
+ void write(int idx, Score w, Score b = SCORE_ZERO);
+ void print(std::stringstream& ss, const char* name, int idx);
std::string do_trace(const Position& pos);
}
- // Evaluation weights, initialized from UCI options
- enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem };
- struct Weight { int mg, eg; } Weights[6];
+ // Evaluation weights, indexed by evaluation term
+ enum { Mobility, PawnStructure, PassedPawns, Space, KingSafety };
+ const struct Weight { int mg, eg; } Weights[] = {
+ {289, 344}, {233, 201}, {221, 273}, {46, 0}, {322, 0}
+ };
- typedef Value V;
+ #define V(v) Value(v)
#define S(mg, eg) make_score(mg, eg)
- // Internal evaluation weights. These are applied on top of the evaluation
- // weights read from UCI parameters. The purpose is to be able to change
- // the evaluation weights while keeping the default values of the UCI
- // parameters at 100, which looks prettier.
- //
- // Values modified by Joona Kiiski
- const Score WeightsInternal[] = {
- S(289, 344), S(233, 201), S(221, 273), S(46, 0), S(271, 0), S(307, 0)
- };
-
// 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(-65,-50), S(-42,-30), 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(-52,-47), S(-28,-23), 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(-17,-33), S(-11,-16), S(-5, 0), S( 1, 16), S( 7, 32), S(13, 48), // Rooks
+ { S(-47,-53), S(-31,-26), 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(-12,-20), S( -8,-13), S(-5, -7), S( 0, 0), S( 6, 10), S(11, 19), // Queens
+ { S(-42,-40), S(-28,-23), S(-5, -7), S( 0, 0), S( 6, 10), S(11, 19), // Queens
S( 13, 29), S( 18, 38), S(20, 40), S(21, 41), S(22, 41), S(22, 41),
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),
V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0) }
};
- // 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
+ // Threat[defended/weak][minor/major attacking][attacked PieceType] contains
+ // bonuses according to which piece type attacks which one.
+ const Score Threat[][2][PIECE_TYPE_NB] = {
+ { { S(0, 0), S( 0, 0), S(19, 37), S(24, 37), S(44, 97), S(35,106) }, // Defended Minor
+ { S(0, 0), S( 0, 0), S( 9, 14), S( 9, 14), S( 7, 14), S(24, 48) } }, // Defended Major
+ { { S(0, 0), S( 0,32), S(33, 41), S(31, 50), S(41,100), S(35,104) }, // Weak Minor
+ { S(0, 0), S( 0,27), S(26, 57), S(26, 57), S(0 , 43), S(23, 51) } } // Weak Major
};
// 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)
+ S(0, 0), S(0, 0), S(87, 118), S(84, 122), S(114, 203), S(121, 217)
};
- #undef S
-
- const Score Tempo = make_score(24, 11);
- const Score RookOn7th = make_score(11, 20);
- const Score RookOnPawn = make_score(10, 28);
- 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);
- const Score LowMobPenalty = make_score(40, 20);
+ // Assorted bonuses and penalties used by evaluation
+ const Score KingOnOne = S( 2, 58);
+ const Score KingOnMany = S( 6,125);
+ const Score RookOnPawn = S( 7, 27);
+ const Score RookOnOpenFile = S(43, 21);
+ const Score RookOnSemiOpenFile = S(19, 10);
+ const Score BishopPawns = S( 8, 12);
+ const Score MinorBehindPawn = S(16, 0);
+ const Score TrappedRook = S(92, 0);
+ const Score Unstoppable = S( 0, 20);
+ const Score Hanging = S(31, 26);
+ const Score PawnAttackThreat = S(20, 20);
+ const Score PawnSafePush = S( 5, 5);
// 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 TrappedBishopA1H1 = make_score(50, 50);
+ const Score TrappedBishopA1H1 = S(50, 50);
+
+ #undef S
+ #undef V
// SpaceMask[Color] contains the area of the board which is considered
// by the space evaluation. In the middlegame, each side is given a bonus
(FileCBB | FileDBB | FileEBB | FileFBB) & (Rank7BB | Rank6BB | Rank5BB)
};
- const Bitboard EdgeBB = Rank1BB | Rank8BB | FileABB | FileHBB;
-
- // King danger constants and variables. The king danger scores are taken
- // from KingDanger[]. Various little "meta-bonuses" measuring the strength
+ // King danger constants and variables. The king danger scores are looked-up
+ // in 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 };
+ const int KingAttackWeights[] = { 0, 0, 7, 5, 4, 1 };
// Bonuses for enemy's safe checks
- const int QueenContactCheck = 24;
- const int RookContactCheck = 16;
- const int QueenCheck = 12;
- const int RookCheck = 8;
- const int BishopCheck = 2;
- const int KnightCheck = 3;
-
- // 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);
-
- template<Color Us>
- void init_eval_info(const Position& pos, EvalInfo& ei);
-
- template<PieceType Pt, Color Us, bool Trace>
- Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, Bitboard* mobilityArea);
-
- template<Color Us, bool Trace>
- Score evaluate_king(const Position& pos, const EvalInfo& ei);
-
- template<Color Us, bool Trace>
- Score evaluate_threats(const Position& pos, const EvalInfo& ei);
-
- template<Color Us, bool Trace>
- Score evaluate_passed_pawns(const Position& pos, const EvalInfo& ei);
-
- template<Color Us>
- int evaluate_space(const Position& pos, const 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, const Weight& w);
- Weight weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
-}
-
-
-namespace Eval {
-
- /// evaluate() is the main evaluation function. It always computes two
- /// values, an endgame score and a middlegame score, and interpolates
- /// between them based on the remaining material.
-
- Value evaluate(const Position& pos) {
- return do_evaluate<false>(pos);
+ const int QueenContactCheck = 89;
+ const int RookContactCheck = 71;
+ const int QueenCheck = 50;
+ const int RookCheck = 37;
+ const int BishopCheck = 6;
+ const int KnightCheck = 14;
+
+ // KingDanger[attackUnits] contains the actual king danger weighted
+ // scores, indexed by a calculated integer number.
+ Score KingDanger[512];
+
+ // apply_weight() weighs score 's' by weight 'w' trying to prevent overflow
+ Score apply_weight(Score s, const Weight& w) {
+ return make_score(mg_value(s) * w.mg / 256, eg_value(s) * w.eg / 256);
}
- /// 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);
- }
-
-
- /// init() computes evaluation weights from the corresponding UCI parameters
- /// and setup king tables.
-
- void init() {
-
- Weights[Mobility] = weight_option("Mobility (Midgame)", "Mobility (Endgame)", WeightsInternal[Mobility]);
- Weights[PawnStructure] = weight_option("Pawn Structure (Midgame)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
- Weights[PassedPawns] = weight_option("Passed Pawns (Midgame)", "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]);
-
- 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));
-
- KingDanger[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]);
- KingDanger[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]);
- }
- }
-
-} // namespace Eval
-
-
-namespace {
-
-template<bool Trace>
-Value do_evaluate(const Position& pos) {
-
- assert(!pos.checkers());
-
- EvalInfo ei;
- Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO };
- Thread* thisThread = pos.this_thread();
-
- // Initialize score by reading the incrementally updated scores included
- // 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);
-
- // Probe the material hash table
- ei.mi = Material::probe(pos, thisThread->materialTable, thisThread->endgames);
- score += ei.mi->material_value();
-
- // If we have a specialized evaluation function for the current material
- // configuration, call it and return.
- if (ei.mi->specialized_eval_exists())
- return ei.mi->evaluate(pos);
-
- // Probe the pawn hash table
- ei.pi = Pawns::probe(pos, thisThread->pawnsTable);
- score += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
-
- // Initialize attack and king safety bitboards
- init_eval_info<WHITE>(pos, ei);
- init_eval_info<BLACK>(pos, ei);
-
- ei.attackedBy[WHITE][ALL_PIECES] |= ei.attackedBy[WHITE][KING];
- ei.attackedBy[BLACK][ALL_PIECES] |= ei.attackedBy[BLACK][KING];
-
- // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
- Bitboard mobilityArea[] = { ~(ei.attackedBy[BLACK][PAWN] | pos.pieces(WHITE, PAWN, KING)),
- ~(ei.attackedBy[WHITE][PAWN] | pos.pieces(BLACK, PAWN, KING)) };
-
- // Evaluate pieces and mobility
- score += evaluate_pieces<KNIGHT, WHITE, Trace>(pos, ei, mobility, mobilityArea);
- 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)
- - evaluate_king<BLACK, Trace>(pos, ei);
-
- // Evaluate tactical threats, we need full attack information including king
- score += evaluate_threats<WHITE, Trace>(pos, ei)
- - evaluate_threats<BLACK, Trace>(pos, ei);
-
- // Evaluate passed pawns, we need full attack information including king
- score += evaluate_passed_pawns<WHITE, Trace>(pos, ei)
- - evaluate_passed_pawns<BLACK, Trace>(pos, ei);
-
- // 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, WHITE, ei)
- - evaluate_unstoppable_pawns(pos, BLACK, ei);
-
- // 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(s * ei.mi->space_weight(), Weights[Space]);
- }
-
- // 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);
-
- // If we don't already have an unusual scale factor, check for opposite
- // colored bishop endgames, and use a lower scale for those.
- if ( ei.mi->game_phase() < PHASE_MIDGAME
- && pos.opposite_bishops()
- && (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN))
- {
- // 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.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK) == 1);
- sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
- }
- else
- // 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 * sf / SCALE_FACTOR_NORMAL);
- }
-
- 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)
- {
- Tracing::add_term(Tracing::PST, pos.psq_score());
- Tracing::add_term(Tracing::IMBALANCE, ei.mi->material_value());
- Tracing::add_term(PAWN, ei.pi->pawns_value());
- Tracing::add_term(Tracing::MOBILITY, apply_weight(mobility[WHITE], Weights[Mobility])
- , apply_weight(mobility[BLACK], Weights[Mobility]));
- Score w = ei.mi->space_weight() * evaluate_space<WHITE>(pos, ei);
- Score b = ei.mi->space_weight() * evaluate_space<BLACK>(pos, ei);
- Tracing::add_term(Tracing::SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
- Tracing::add_term(Tracing::TOTAL, score);
- Tracing::ei = ei;
- Tracing::sf = sf;
- }
-
- return pos.side_to_move() == WHITE ? v : -v;
-}
-
-
// init_eval_info() initializes king bitboards for given color adding
// pawn attacks. To be done at the beginning of the evaluation.
ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
// Init king safety tables only if we are going to use them
- if (pos.count<QUEEN>(Us) && pos.non_pawn_material(Us) > QueenValueMg + PawnValueMg)
+ if (pos.non_pawn_material(Us) >= QueenValueMg)
{
ei.kingRing[Them] = b | shift_bb<Down>(b);
b &= ei.attackedBy[Us][PAWN];
}
- // evaluate_outposts() evaluates bishop and knight outpost squares
+ // evaluate_outpost() evaluates bishop and knight outpost squares
template<PieceType Pt, Color Us>
- Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
+ Score evaluate_outpost(const Position& pos, const EvalInfo& ei, Square s) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
bonus += bonus / 2;
}
- return make_score(bonus, bonus);
+ return make_score(bonus * 2, bonus / 2);
}
Square s;
Score score = SCORE_ZERO;
+ const PieceType NextPt = (Us == WHITE ? Pt : PieceType(Pt + 1));
const Color Them = (Us == WHITE ? BLACK : WHITE);
const Square* pl = pos.list<Pt>(Us);
mobility[Us] += MobilityBonus[Pt][mob];
- if (mob <= 1 && (EdgeBB & s))
- score -= LowMobPenalty;
-
// 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)
if (Pt == BISHOP || Pt == KNIGHT)
{
- // Penalty for bishop with same colored pawns
- if (Pt == BISHOP)
- score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s);
-
- // Penalty for knight when there are few enemy pawns
- if (Pt == KNIGHT)
- score -= KnightPawns * std::max(5 - pos.count<PAWN>(Them), 0);
-
- // Bishop and knight outposts squares
+ // Bonus for outpost square
if (!(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s)))
- score += evaluate_outpost
s<Pt, Us>(pos, ei, s);
+ score += evaluate_outpost<Pt, Us>(pos, ei, s);
- // Bishop or knight behind a pawn
+ // Bonus when behind a pawn
if ( relative_rank(Us, s) < RANK_5
&& (pos.pieces(PAWN) & (s + pawn_push(Us))))
score += MinorBehindPawn;
+
+ // Penalty for pawns on same color square of bishop
+ if (Pt == BISHOP)
+ score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s);
+
+ // An important Chess960 pattern: A cornered bishop blocked by a friendly
+ // pawn diagonally in front of it is a very serious problem, especially
+ // when that pawn is also blocked.
+ if ( Pt == BISHOP
+ && pos.is_chess960()
+ && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
+ {
+ Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
+ if (pos.piece_on(s + d) == make_piece(Us, PAWN))
+ score -= !pos.empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4
+ : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? TrappedBishopA1H1 * 2
+ : TrappedBishopA1H1;
+ }
}
if (Pt == ROOK)
{
- // Rook 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 += RookOn7th;
-
- // Rook piece attacking enemy pawns on the same rank/file
+ // Bonus for aligning with enemy pawns on the same rank/file
if (relative_rank(Us, s) >= RANK_5)
{
- Bitboard pawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s];
- if (pawns)
- score += popcount<Max15>(pawns) * RookOnPawn;
+ Bitboard alignedPawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s];
+ if (alignedPawns)
+ score += popcount<Max15>(alignedPawns) * RookOnPawn;
}
- // 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;
+ // Bonus when on an open or semi-open file
+ if (ei.pi->semiopen_file(Us, file_of(s)))
+ score += ei.pi->semiopen_file(Them, file_of(s)) ? RookOnOpenFile : RookOnSemiOpenFile;
- Square ksq = pos.king_square(Us);
-
- // 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->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);
- }
+ // Penalize when trapped by the king, even more if king cannot castle
+ if (mob <= 3 && !ei.pi->semiopen_file(Us, file_of(s)))
+ {
+ Square ksq = pos.king_square(Us);
- // An important Chess960 pattern: A cornered bishop blocked by a friendly
- // pawn diagonally in front of it is a very serious problem, especially
- // when that pawn is also blocked.
- if ( Pt == BISHOP
- && pos.is_chess960()
- && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
- {
- Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
- if (pos.piece_on(s + d) == make_piece(Us, PAWN))
- score -= !pos.empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4
- : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? TrappedBishopA1H1 * 2
- : TrappedBishopA1H1;
+ 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->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq)))
+ score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us));
+ }
}
}
if (Trace)
- Tracing::terms[Us][Pt] = score;
-
- const PieceType NextPt = (Us == WHITE ? Pt : PieceType(Pt + 1));
+ Tracing::write(Pt, Us, score);
+ // Recursively call evaluate_pieces() of next piece type until KING excluded
return score - evaluate_pieces<NextPt, Them, Trace>(pos, ei, mobility, mobilityArea);
}
| ei.attackedBy[Us][QUEEN]);
// Initialize the 'attackUnits' variable, which is used later on as an
- // index to the KingDanger[] array. The initial value is based on the
+ // index into 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))
- + 2 * (ei.pinnedPieces[Us] != 0)
- - mg_value(score) / 32;
+ attackUnits = std::min(74, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
+ + 8 * ei.kingAdjacentZoneAttacksCount[Them]
+ + 25 * popcount<Max15>(undefended)
+ + 11 * (ei.pinnedPieces[Us] != 0)
+ - mg_value(score) / 8
+ - !pos.count<QUEEN>(Them) * 60;
// Analyse the enemy's safe queen contact checks. Firstly, find the
- // undefended squares around the king that are attacked by the enemy's
- // queen...
+ // undefended squares around the king reachable by the enemy queen...
b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
if (b)
{
// ...and then remove squares not supported by another enemy piece
- b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
- | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
+ b &= ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
+ | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK];
if (b)
- attackUnits += QueenContactCheck
- * popcount<Max15>(b)
- * (Them == pos.side_to_move() ? 2 : 1);
+ attackUnits += QueenContactCheck * popcount<Max15>(b);
}
// Analyse the enemy's safe rook contact checks. Firstly, find the
- // undefended squares around the king that are attacked by the enemy's
- // rooks...
+ // undefended squares around the king reachable by the enemy rooks...
b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
// Consider only squares where the enemy's rook gives check
| ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]);
if (b)
- attackUnits += RookContactCheck
- * popcount<Max15>(b)
- * (Them == pos.side_to_move() ? 2 : 1);
+ attackUnits += RookContactCheck * popcount<Max15>(b);
}
// Analyse the enemy's safe distance checks for sliders and knights
- safe = ~(pos.pieces(Them) | ei.attackedBy[Us][ALL_PIECES]);
+ safe = ~(ei.attackedBy[Us][ALL_PIECES] | pos.pieces(Them));
- b1 = pos.attacks_from<ROOK>(ksq) & safe;
+ b1 = pos.attacks_from<ROOK >(ksq) & safe;
b2 = pos.attacks_from<BISHOP>(ksq) & safe;
// Enemy queen safe checks
if (b)
attackUnits += KnightCheck * popcount<Max15>(b);
- // 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 KingDanger[]
// array and subtract the score from evaluation.
- score -= KingDanger[Us == Search::RootColor][attackUnits];
+ score -= KingDanger[std::max(std::min(attackUnits, 399), 0)];
}
if (Trace)
- Tracing::terms[Us][KING] = score;
+ Tracing::write(KING, Us, score);
return score;
}
template<Color Us, bool Trace>
Score evaluate_threats(const Position& pos, const EvalInfo& ei) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Square Up = (Us == WHITE ? DELTA_N : DELTA_S);
+ const Square Left = (Us == WHITE ? DELTA_NW : DELTA_SE);
+ const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW);
+ const Bitboard TRank2BB = (Us == WHITE ? Rank2BB : Rank7BB);
+ const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
- Bitboard b, undefendedMinors, weakEnemies;
+ enum { Defended, Weak };
+ enum { Minor, Major };
+
+ Bitboard b, weak, defended;
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];
+ // Non-pawn enemies defended by a pawn
+ defended = (pos.pieces(Them) ^ pos.pieces(Them, PAWN))
+ & ei.attackedBy[Them][PAWN];
- if (undefendedMinors)
- score += UndefendedMinor;
+ // Add a bonus according to the kind of attacking pieces
+ if (defended)
+ {
+ b = defended & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
+ while (b)
+ score += Threat[Defended][Minor][type_of(pos.piece_on(pop_lsb(&b)))];
- // Enemy pieces not defended by a pawn and under our attack
- weakEnemies = pos.pieces(Them)
- & ~ei.attackedBy[Them][PAWN]
- & ei.attackedBy[Us][ALL_PIECES];
+ b = defended & (ei.attackedBy[Us][ROOK]);
+ while (b)
+ score += Threat[Defended][Major][type_of(pos.piece_on(pop_lsb(&b)))];
+ }
- // Add a bonus according if the attacking pieces are minor or major
- if (weakEnemies)
+ // Enemies not defended by a pawn and under our attack
+ weak = pos.pieces(Them)
+ & ~ei.attackedBy[Them][PAWN]
+ & ei.attackedBy[Us][ALL_PIECES];
+
+ // Add a bonus according to the kind of attacking pieces
+ if (weak)
{
- b = weakEnemies & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
+ b = weak & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
+ while (b)
+ score += Threat[Weak][Minor][type_of(pos.piece_on(pop_lsb(&b)))];
+
+ b = weak & (ei.attackedBy[Us][ROOK] | ei.attackedBy[Us][QUEEN]);
+ while (b)
+ score += Threat[Weak][Major][type_of(pos.piece_on(pop_lsb(&b)))];
+
+ b = weak & ~ei.attackedBy[Them][ALL_PIECES];
if (b)
- score += Threat[0][type_of(pos.piece_on(lsb(b)))];
+ score += Hanging * popcount<Max15>(b);
- b = weakEnemies & (ei.attackedBy[Us][ROOK] | ei.attackedBy[Us][QUEEN]);
+ b = weak & ei.attackedBy[Us][KING];
if (b)
- score += Threat[1][type_of(pos.piece_on(lsb(b)))];
+ score += more_than_one(b) ? KingOnMany : KingOnOne;
}
+ // Add a small bonus for safe pawn pushes
+ b = pos.pieces(Us, PAWN) & ~TRank7BB;
+ b = shift_bb<Up>(b | (shift_bb<Up>(b & TRank2BB) & ~pos.pieces()));
+
+ b &= ~pos.pieces()
+ & ~ei.attackedBy[Them][PAWN]
+ & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
+
+ if (b)
+ score += popcount<Full>(b) * PawnSafePush;
+
+ // Add another bonus if the pawn push attacks an enemy piece
+ b = (shift_bb<Left>(b) | shift_bb<Right>(b))
+ & pos.pieces(Them)
+ & ~ei.attackedBy[Us][PAWN];
+
+ if (b)
+ score += popcount<Max15>(b) * PawnAttackThreat;
+
if (Trace)
- Tracing::terms[Us][Tracing::THREAT] = score;
+ Tracing::write(Tracing::THREAT, Us, score);
return score;
}
const Color Them = (Us == WHITE ? BLACK : WHITE);
- Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
+ Bitboard b, squaresToQueen, defendedSquares, unsafeSquares;
Score score = SCORE_ZERO;
b = ei.pi->passed_pawns(Us);
assert(pos.pawn_passed(Us, s));
- int r = int(relative_rank(Us, s) - RANK_2);
+ int r = relative_rank(Us, s) - RANK_2;
int rr = r * (r - 1);
// Base bonus based on rank
- Value mbonus = Value(17 * rr);
- Value ebonus = Value(7 * (rr + r + 1));
+ Value mbonus = Value(17 * rr), ebonus = Value(7 * (rr + r + 1));
if (rr)
{
Square blockSq = s + pawn_push(Us);
// 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);
+ ebonus += distance(pos.king_square(Them), blockSq) * 5 * rr
+ - distance(pos.king_square(Us ), blockSq) * 2 * rr;
// If blockSq is not the queening square then consider also a second push
if (relative_rank(Us, blockSq) != RANK_8)
- ebonus -= Value(rr * square_distance(pos.king_square(Us), blockSq + pawn_push(Us)));
+ ebonus -= distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr;
// If the pawn is free to advance, then increase the bonus
if (pos.empty(blockSq))
{
- squaresToQueen = forward_bb(Us, s);
-
- // 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 ( 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 ( 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;
-
- // 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 there is a rook or queen attacking/defending the pawn from behind,
+ // consider all the squaresToQueen. Otherwise consider only the squares
+ // in the pawn's path attacked or occupied by the enemy.
+ defendedSquares = unsafeSquares = squaresToQueen = forward_bb(Us, s);
+
+ Bitboard bb = forward_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from<ROOK>(s);
+
+ if (!(pos.pieces(Us) & bb))
+ defendedSquares &= ei.attackedBy[Us][ALL_PIECES];
+
+ if (!(pos.pieces(Them) & bb))
+ unsafeSquares &= ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them);
+
+ // If there aren't any enemy attacks, assign a big bonus. Otherwise
+ // assign a smaller bonus if the block square isn't attacked.
+ int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 0;
+
+ // If the path to queen is fully defended, assign a big bonus.
+ // Otherwise assign a smaller bonus if the block square is defended.
if (defendedSquares == squaresToQueen)
k += 6;
else if (defendedSquares & blockSq)
- k += (unsafeSquares & defendedSquares) == unsafeSquares ? 4 : 2;
+ k += 4;
- mbonus += Value(k * rr), ebonus += Value(k * rr);
+ mbonus += k * rr, ebonus += k * rr;
}
+ else if (pos.pieces(Us) & blockSq)
+ mbonus += rr * 3 + r * 2 + 3, ebonus += rr + r * 2;
} // 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(Us, PAWN) & 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);
-
- // Rook pawns are a special case: They are sometimes worse, and
- // sometimes better than other passed pawns. It is difficult to find
- // good rules for determining whether they are good or bad. For now,
- // 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 (file_of(s) == FILE_A || file_of(s) == FILE_H)
- {
- 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;
}
if (Trace)
- Tracing::terms[Us][Tracing::PASSED] = apply_weight(score, Weights[PassedPawns]);
+ Tracing::write(Tracing::PASSED, Us, apply_weight(score, Weights[PassedPawns]));
// Add the scores to the middlegame and endgame eval
return apply_weight(score, Weights[PassedPawns]);
}
- // 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.
-
- Score evaluate_unstoppable_pawns(const Position& pos, Color us, const EvalInfo& ei) {
-
- Bitboard b = ei.pi->passed_pawns(us) | ei.pi->candidate_pawns(us);
-
- if (!b || pos.non_pawn_material(~us))
- return SCORE_ZERO;
-
- return Unstoppable * int(relative_rank(us, frontmost_sq(us, b)));
- }
-
-
// evaluate_space() computes the space evaluation for a given side. The
// space evaluation is a simple bonus based on the number of safe squares
// 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. The aim is to improve play on game opening.
+ // twice. Finally, the space bonus is multiplied by a weight. The aim is to
+ // improve play on game opening.
template<Color Us>
- int evaluate_space(const Position& pos, const EvalInfo& ei) {
+ Score evaluate_space(const Position& pos, const EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);
// Count safe + (behind & safe) with a single popcount
- return popcount<Full>((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
+ int bonus = popcount<Full>((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
+ int weight = pos.count<KNIGHT>(Us) + pos.count<BISHOP>(Us)
+ + pos.count<KNIGHT>(Them) + pos.count<BISHOP>(Them);
+
+ return make_score(bonus * weight * weight, 0);
}
- // interpolate() interpolates between a middlegame and an endgame score,
- // based on game phase. It also scales the return value by a ScaleFactor array.
+ // do_evaluate() is the evaluation entry point, called directly from evaluate()
- Value interpolate(const Score& v, Phase ph, ScaleFactor sf) {
+ template<bool Trace>
+ Value do_evaluate(const Position& pos) {
- assert(-VALUE_INFINITE < mg_value(v) && mg_value(v) < VALUE_INFINITE);
- assert(-VALUE_INFINITE < eg_value(v) && eg_value(v) < VALUE_INFINITE);
- assert(PHASE_ENDGAME <= ph && ph <= PHASE_MIDGAME);
+ assert(!pos.checkers());
- int eg = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
- return Value((mg_value(v) * int(ph) + eg * int(PHASE_MIDGAME - ph)) / PHASE_MIDGAME);
- }
+ EvalInfo ei;
+ Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO };
- // apply_weight() weights score v by score w trying to prevent overflow
- Score apply_weight(Score v, const Weight& w) {
+ // Initialize score by reading the incrementally updated scores included
+ // in the position object (material + piece square tables).
+ // Score is computed from the point of view of white.
+ score = pos.psq_score();
- return make_score(mg_value(v) * w.mg / 256, eg_value(v) * w.eg / 256);
- }
+ // Probe the material hash table
+ ei.mi = Material::probe(pos);
+ score += ei.mi->imbalance();
+
+ // If we have a specialized evaluation function for the current material
+ // configuration, call it and return.
+ if (ei.mi->specialized_eval_exists())
+ return ei.mi->evaluate(pos);
+
+ // Probe the pawn hash table
+ ei.pi = Pawns::probe(pos);
+ score += apply_weight(ei.pi->pawns_score(), Weights[PawnStructure]);
+
+ // Initialize attack and king safety bitboards
+ init_eval_info<WHITE>(pos, ei);
+ init_eval_info<BLACK>(pos, ei);
+
+ ei.attackedBy[WHITE][ALL_PIECES] |= ei.attackedBy[WHITE][KING];
+ ei.attackedBy[BLACK][ALL_PIECES] |= ei.attackedBy[BLACK][KING];
+
+ // Do not include in mobility squares protected by enemy pawns or occupied by our pawns or king
+ Bitboard mobilityArea[] = { ~(ei.attackedBy[BLACK][PAWN] | pos.pieces(WHITE, PAWN, KING)),
+ ~(ei.attackedBy[WHITE][PAWN] | pos.pieces(BLACK, PAWN, KING)) };
+
+ // Evaluate pieces and mobility
+ score += evaluate_pieces<KNIGHT, WHITE, Trace>(pos, ei, mobility, mobilityArea);
+ 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)
+ - evaluate_king<BLACK, Trace>(pos, ei);
- // weight_option() computes the value of an evaluation weight, by combining
- // two UCI-configurable weights (midgame and endgame) with an internal weight.
+ // Evaluate tactical threats, we need full attack information including king
+ score += evaluate_threats<WHITE, Trace>(pos, ei)
+ - evaluate_threats<BLACK, Trace>(pos, ei);
- Weight weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
+ // Evaluate passed pawns, we need full attack information including king
+ score += evaluate_passed_pawns<WHITE, Trace>(pos, ei)
+ - evaluate_passed_pawns<BLACK, Trace>(pos, ei);
- Weight w = { Options[mgOpt] * mg_value(internalWeight) / 100,
- Options[egOpt] * eg_value(internalWeight) / 100 };
- return w;
+ // If both sides have only pawns, score for potential unstoppable pawns
+ if (!pos.non_pawn_material(WHITE) && !pos.non_pawn_material(BLACK))
+ {
+ Bitboard b;
+ if ((b = ei.pi->passed_pawns(WHITE)) != 0)
+ score += int(relative_rank(WHITE, frontmost_sq(WHITE, b))) * Unstoppable;
+
+ if ((b = ei.pi->passed_pawns(BLACK)) != 0)
+ score -= int(relative_rank(BLACK, frontmost_sq(BLACK, b))) * Unstoppable;
+ }
+
+ // Evaluate space for both sides, only during opening
+ if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= 2 * QueenValueMg + 4 * RookValueMg + 2 * KnightValueMg)
+ {
+ Score s = evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei);
+ score += apply_weight(s, Weights[Space]);
+ }
+
+ // Scale winning side if position is more drawish than it appears
+ Color strongSide = eg_value(score) > VALUE_DRAW ? WHITE : BLACK;
+ ScaleFactor sf = ei.mi->scale_factor(pos, strongSide);
+
+ // If we don't already have an unusual scale factor, check for certain
+ // types of endgames, and use a lower scale for those.
+ if ( ei.mi->game_phase() < PHASE_MIDGAME
+ && (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN))
+ {
+ if (pos.opposite_bishops())
+ {
+ // Endgame with opposite-colored bishops and no other pieces (ignoring pawns)
+ // is almost a draw, in case of KBP vs KB is even more a draw.
+ if ( pos.non_pawn_material(WHITE) == BishopValueMg
+ && pos.non_pawn_material(BLACK) == BishopValueMg)
+ sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(32) : ScaleFactor(8);
+
+ // Endgame with opposite-colored bishops, but also other pieces. Still
+ // a bit drawish, but not as drawish as with only the two bishops.
+ else
+ sf = ScaleFactor(50 * sf / SCALE_FACTOR_NORMAL);
+ }
+ // Endings where weaker side can place his king in front of the opponent's
+ // pawns are drawish.
+ else if ( abs(eg_value(score)) <= BishopValueEg
+ && ei.pi->pawn_span(strongSide) <= 1
+ && !pos.pawn_passed(~strongSide, pos.king_square(~strongSide)))
+ sf = ei.pi->pawn_span(strongSide) ? ScaleFactor(56) : ScaleFactor(38);
+ }
+
+ // Interpolate between a middlegame and a (scaled by 'sf') endgame score
+ Value v = mg_value(score) * int(ei.mi->game_phase())
+ + eg_value(score) * int(PHASE_MIDGAME - ei.mi->game_phase()) * sf / SCALE_FACTOR_NORMAL;
+
+ v /= int(PHASE_MIDGAME);
+
+ // In case of tracing add all single evaluation contributions for both white and black
+ if (Trace)
+ {
+ Tracing::write(Tracing::MATERIAL, pos.psq_score());
+ Tracing::write(Tracing::IMBALANCE, ei.mi->imbalance());
+ Tracing::write(PAWN, ei.pi->pawns_score());
+ Tracing::write(Tracing::MOBILITY, apply_weight(mobility[WHITE], Weights[Mobility])
+ , apply_weight(mobility[BLACK], Weights[Mobility]));
+ Tracing::write(Tracing::SPACE, apply_weight(evaluate_space<WHITE>(pos, ei), Weights[Space])
+ , apply_weight(evaluate_space<BLACK>(pos, ei), Weights[Space]));
+ Tracing::write(Tracing::TOTAL, score);
+ Tracing::ei = ei;
+ Tracing::sf = sf;
+ }
+
+ return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo;
}
double Tracing::to_cp(Value v) { return double(v) / PawnValueEg; }
- void Tracing::add_term(int idx, Score wScore, Score bScore) {
+ void Tracing::write(int idx, Color c, Score s) { scores[c][idx] = s; }
- terms[WHITE][idx] = wScore;
- terms[BLACK][idx] = bScore;
+ void Tracing::write(int idx, Score w, Score b) {
+
+ write(idx, WHITE, w);
+ write(idx, BLACK, b);
}
- void Tracing::format_row(std::stringstream& ss, const char* name, int idx) {
+ void Tracing::print(std::stringstream& ss, const char* name, int idx) {
- Score wScore = terms[WHITE][idx];
- Score bScore = terms[BLACK][idx];
+ Score wScore = scores[WHITE][idx];
+ Score bScore = scores[BLACK][idx];
switch (idx) {
- case PST: case IMBALANCE: case PAWN: case TOTAL:
- ss << std::setw(20) << name << " | --- --- | --- --- | "
+ case MATERIAL: case IMBALANCE: case PAWN: case TOTAL:
+ ss << std::setw(15) << name << " | --- --- | --- --- | "
<< std::setw(5) << to_cp(mg_value(wScore - bScore)) << " "
<< std::setw(5) << to_cp(eg_value(wScore - bScore)) << " \n";
break;
default:
- ss << std::setw(20) << name << " | " << std::noshowpos
+ ss << std::setw(15) << 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::string Tracing::do_trace(const Position& pos) {
- std::memset(terms, 0, sizeof(terms));
+ std::memset(scores, 0, sizeof(scores));
Value v = do_evaluate<true>(pos);
v = pos.side_to_move() == WHITE ? v : -v; // White's point of view
std::stringstream ss;
ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2)
- << " Eval term | White | Black | Total \n"
- << " | MG EG | MG EG | MG EG \n"
- << "---------------------+-------------+-------------+-------------\n";
-
- format_row(ss, "Material, PST, Tempo", PST);
- format_row(ss, "Material imbalance", IMBALANCE);
- format_row(ss, "Pawns", PAWN);
- format_row(ss, "Knights", KNIGHT);
- format_row(ss, "Bishops", BISHOP);
- format_row(ss, "Rooks", ROOK);
- format_row(ss, "Queens", QUEEN);
- format_row(ss, "Mobility", MOBILITY);
- format_row(ss, "King safety", KING);
- format_row(ss, "Threats", THREAT);
- format_row(ss, "Passed pawns", PASSED);
- format_row(ss, "Space", SPACE);
-
- ss << "---------------------+-------------+-------------+-------------\n";
- format_row(ss, "Total", TOTAL);
+ << " Eval term | White | Black | Total \n"
+ << " | MG EG | MG EG | MG EG \n"
+ << "----------------+-------------+-------------+-------------\n";
+
+ print(ss, "Material", MATERIAL);
+ print(ss, "Imbalance", IMBALANCE);
+ print(ss, "Pawns", PAWN);
+ print(ss, "Knights", KNIGHT);
+ print(ss, "Bishops", BISHOP);
+ print(ss, "Rooks", ROOK);
+ print(ss, "Queens", QUEEN);
+ print(ss, "Mobility", MOBILITY);
+ print(ss, "King safety", KING);
+ print(ss, "Threats", THREAT);
+ print(ss, "Passed pawns", PASSED);
+ print(ss, "Space", SPACE);
+
+ ss << "----------------+-------------+-------------+-------------\n";
+ print(ss, "Total", TOTAL);
ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n";
return ss.str();
}
-}
+
+} // namespace
+
+
+namespace Eval {
+
+ /// evaluate() is the main evaluation function. It returns a static evaluation
+ /// of the position always from the point of view of the side to move.
+
+ 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);
+ }
+
+
+ /// init() computes evaluation weights, usually at startup
+
+ void init() {
+
+ const int MaxSlope = 8700;
+ const int Peak = 1280000;
+ int t = 0;
+
+ for (int i = 0; i < 400; ++i)
+ {
+ t = std::min(Peak, std::min(i * i * 27, t + MaxSlope));
+ KingDanger[i] = apply_weight(make_score(t / 1000, 0), Weights[KingSafety]);
+ }
+ }
+
+} // namespace Eval
projects / stockfish / blobdiff