/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008 Marco Costalba
+ Copyright (C) 2008-2010 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
////
#include <cassert>
-#include <cstring>
+#include "bitcount.h"
#include "evaluate.h"
#include "material.h"
#include "pawns.h"
-#include "scale.h"
#include "thread.h"
#include "ucioption.h"
namespace {
- const int Sign[2] = {1, -1};
-
- // Evaluation grain size, must be a power of 2.
- const int GrainSize = 4;
-
- // Evaluation weights
- int WeightMobilityMidgame = 0x100;
- int WeightMobilityEndgame = 0x100;
- int WeightPawnStructureMidgame = 0x100;
- int WeightPawnStructureEndgame = 0x100;
- int WeightPassedPawnsMidgame = 0x100;
- int WeightPassedPawnsEndgame = 0x100;
- int WeightKingSafety[2] = { 0x100, 0x100 };
-
- // 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.
- const int WeightMobilityMidgameInternal = 0x100;
- const int WeightMobilityEndgameInternal = 0x100;
- const int WeightPawnStructureMidgameInternal = 0x100;
- const int WeightPawnStructureEndgameInternal = 0x100;
- const int WeightPassedPawnsMidgameInternal = 0x100;
- const int WeightPassedPawnsEndgameInternal = 0x100;
- const int WeightKingSafetyInternal = 0x100;
- const int WeightKingOppSafetyInternal = 0x100;
-
- // Visually better to define tables constants
- typedef Value V;
-
- // Knight mobility bonus in middle game and endgame, indexed by the number
- // of attacked squares not occupied by friendly piecess.
- const Value MidgameKnightMobilityBonus[] = {
- // 0 1 2 3 4 5 6 7 8
- V(-30), V(-20),V(-10), V(0), V(10), V(20), V(25), V(30), V(30)
+ // Struct EvalInfo contains various information computed and collected
+ // by the evaluation functions.
+ struct EvalInfo {
+
+ // Pointer to pawn hash table entry
+ PawnInfo* pi;
+
+ // attackedBy[color][piece type] is a bitboard representing all squares
+ // attacked by a given color and piece type, attackedBy[color][0] contains
+ // all squares attacked by the given color.
+ Bitboard attackedBy[2][8];
+
+ // kingZone[color] is the zone around the enemy 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,
+ // f7, g7, h7, f6, g6 and h6.
+ Bitboard kingZone[2];
+
+ // kingAttackersCount[color] is the number of pieces of the given color
+ // which attack a square in the kingZone 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
+ // weights of the individual piece types are given by the variables
+ // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
+ // KnightAttackWeight in evaluate.cpp
+ int kingAttackersWeight[2];
+
+ // 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].
+ int kingAdjacentZoneAttacksCount[2];
};
- const Value EndgameKnightMobilityBonus[] = {
- // 0 1 2 3 4 5 6 7 8
- V(-30), V(-20),V(-10), V(0), V(10), V(20), V(25), V(30), V(30)
- };
+ // Evaluation grain size, must be a power of 2
+ const int GrainSize = 8;
- // Bishop mobility bonus in middle game and endgame, indexed by the number
- // of attacked squares not occupied by friendly pieces. X-ray attacks through
- // queens are also included.
- const Value MidgameBishopMobilityBonus[] = {
- // 0 1 2 3 4 5 6 7
- V(-30), V(-15), V(0), V(15), V(30), V(45), V(58), V(66),
- // 8 9 10 11 12 13 14 15
- V( 72), V( 76), V(78), V(80), V(81), V(82), V(83), V(83)
- };
-
- const Value EndgameBishopMobilityBonus[] = {
- // 0 1 2 3 4 5 6 7
- V(-30), V(-15), V(0), V(15), V(30), V(45), V(58), V(66),
- // 8 9 10 11 12 13 14 15
- V( 72), V( 76), V(78), V(80), V(81), V(82), V(83), V(83)
- };
+ // Evaluation weights, initialized from UCI options
+ enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem };
+ Score Weights[6];
- // Rook mobility bonus in middle game and endgame, indexed by the number
- // of attacked squares not occupied by friendly pieces. X-ray attacks through
- // queens and rooks are also included.
- const Value MidgameRookMobilityBonus[] = {
- // 0 1 2 3 4 5 6 7
- V(-18), V(-12), V(-6), V(0), V(6), V(12), V(16), V(21),
- // 8 9 10 11 12 13 14 15
- V( 24), V( 27), V(28), V(29), V(30), V(31), V(32), V(33)
- };
+ typedef Value V;
+ #define S(mg, eg) make_score(mg, eg)
- const Value EndgameRookMobilityBonus[] = {
- // 0 1 2 3 4 5 6 7
- V(-30), V(-18), V(-6), V(6), V(18), V(30), V(42), V(54),
- // 8 9 10 11 12 13 14 15
- V( 66), V( 74), V(78), V(80), V(81), V(82), V(83), V(83)
+ // 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(248, 271), S(233, 201), S(252, 259), S(46, 0), S(247, 0), S(259, 0)
};
- // Queen mobility bonus in middle game and endgame, indexed by the number
- // of attacked squares not occupied by friendly pieces.
- const Value MidgameQueenMobilityBonus[] = {
- // 0 1 2 3 4 5 6 7
- V(-10), V(-8), V(-6), V(-4), V(-2), V( 0), V( 2), V( 4),
- // 8 9 10 11 12 13 14 15
- V( 6), V( 8), V(10), V(12), V(13), V(14), V(15), V(16),
- // 16 17 18 19 20 21 22 23
- V( 16), V(16), V(16), V(16), V(16), V(16), V(16), V(16),
- // 24 25 26 27 28 29 30 31
- V( 16), V(16), V(16), V(16), V(16), V(16), V(16), V(16)
+ // MobilityBonus[PieceType][attacked] contains mobility bonuses for middle and
+ // end game, indexed by piece type and number of attacked squares not occupied
+ // by friendly pieces.
+ const Score MobilityBonus[][32] = {
+ {}, {},
+ { S(-38,-33), S(-25,-23), S(-12,-13), S( 0, -3), S(12, 7), S(25, 17), // Knights
+ S( 31, 22), S( 38, 27), S( 38, 27) },
+ { S(-25,-30), S(-11,-16), S( 3, -2), S(17, 12), S(31, 26), S(45, 40), // Bishops
+ S( 57, 52), S( 65, 60), S( 71, 65), S(74, 69), S(76, 71), S(78, 73),
+ S( 79, 74), S( 80, 75), S( 81, 76), S(81, 76) },
+ { S(-20,-36), S(-14,-19), S( -8, -3), S(-2, 13), S( 4, 29), S(10, 46), // Rooks
+ S( 14, 62), S( 19, 79), S( 23, 95), S(26,106), S(27,111), S(28,114),
+ S( 29,116), S( 30,117), S( 31,118), S(32,118) },
+ { S(-10,-18), S( -8,-13), S( -6, -7), S(-3, -2), S(-1, 3), S( 1, 8), // Queens
+ S( 3, 13), S( 5, 19), S( 8, 23), S(10, 27), S(12, 32), S(15, 34),
+ S( 16, 35), S( 17, 35), S( 18, 35), S(20, 35), S(20, 35), S(20, 35),
+ S( 20, 35), S( 20, 35), S( 20, 35), S(20, 35), S(20, 35), S(20, 35),
+ S( 20, 35), S( 20, 35), S( 20, 35), S(20, 35), S(20, 35), S(20, 35),
+ S( 20, 35), S( 20, 35) }
};
- const Value EndgameQueenMobilityBonus[] = {
- // 0 1 2 3 4 5 6 7
- V(-20),V(-15),V(-10), V(-5), V( 0), V( 5), V(10), V(15),
- // 8 9 10 11 12 13 14 15
- V( 19), V(23), V(27), V(29), V(30), V(30), V(30), V(30),
- // 16 17 18 19 20 21 22 23
- V( 30), V(30), V(30), V(30), V(30), V(30), V(30), V(30),
- // 24 25 26 27 28 29 30 31
- V( 30), V(30), V(30), V(30), V(30), V(30), V(30), V(30)
+ // OutpostBonus[PieceType][Square] contains outpost bonuses of knights and
+ // bishops, indexed by piece type and square (from white's point of view).
+ const Value OutpostBonus[][64] = {
+ {
+ // A B C D E F G H
+ V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Knights
+ V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
+ 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), // 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) }
};
- // Outpost bonuses for knights and bishops, indexed by square (from white's
- // point of view).
- const Value KnightOutpostBonus[64] = {
- // A B C D E F G H
- V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 1
- V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 2
- V(0), V(0), V(5),V(10),V(10), V(5), V(0), V(0), // 3
- V(0), V(5),V(20),V(30),V(30),V(20), V(5), V(0), // 4
- V(0),V(10),V(30),V(40),V(40),V(30),V(10), V(0), // 5
- V(0), V(5),V(20),V(20),V(20),V(20), V(5), V(0), // 6
- V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 7
- V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8
+ // ThreatBonus[attacking][attacked] contains threat bonuses according to
+ // which piece type attacks which one.
+ const Score ThreatBonus[][8] = {
+ {}, {},
+ { S(0, 0), S( 7, 39), S( 0, 0), S(24, 49), S(41,100), S(41,100) }, // KNIGHT
+ { S(0, 0), S( 7, 39), S(24, 49), S( 0, 0), S(41,100), S(41,100) }, // BISHOP
+ { S(0, 0), S(-1, 29), S(15, 49), S(15, 49), S( 0, 0), S(24, 49) }, // ROOK
+ { S(0, 0), S(15, 39), S(15, 39), S(15, 39), S(15, 39), S( 0, 0) } // QUEEN
};
- const Value BishopOutpostBonus[64] = {
- // A B C D E F G H
- V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 1
- V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 2
- V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0), // 3
- V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0), // 4
- V(0),V(10),V(20),V(20),V(20),V(20),V(10), V(0), // 5
- V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0), // 6
- V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 7
- V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8
+ // ThreatedByPawnPenalty[PieceType] contains a penalty according to which
+ // piece type is attacked by an enemy pawn.
+ const Score ThreatedByPawnPenalty[] = {
+ S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
};
- // Bonus for unstoppable passed pawns:
- const Value UnstoppablePawnValue = Value(0x500);
+ #undef S
- // Rooks and queens on the 7th rank:
- const Value MidgameRookOn7thBonus = Value(50);
- const Value EndgameRookOn7thBonus = Value(100);
- const Value MidgameQueenOn7thBonus = Value(25);
- const Value EndgameQueenOn7thBonus = Value(50);
+ // Rooks and queens on the 7th rank (modified by Joona Kiiski)
+ const Score RookOn7thBonus = make_score(47, 98);
+ const Score QueenOn7thBonus = make_score(27, 54);
- // Rooks on open files:
- const Value RookOpenFileBonus = Value(40);
- const Value RookHalfOpenFileBonus = Value(20);
+ // Rooks on open files (modified by Joona Kiiski)
+ const Score RookOpenFileBonus = make_score(43, 43);
+ const Score RookHalfOpenFileBonus = make_score(19, 19);
// Penalty for rooks trapped inside a friendly king which has lost the
- // right to castle:
+ // right to castle.
const Value TrappedRookPenalty = Value(180);
- // Penalty for a bishop on a7/h7 (a2/h2 for black) which is trapped by
- // enemy pawns:
- const Value TrappedBishopA7H7Penalty = Value(300);
-
- // Bitboard masks for detecting trapped bishops on a7/h7 (a2/h2 for black):
- const Bitboard MaskA7H7[2] = {
- ((1ULL << SQ_A7) | (1ULL << SQ_H7)),
- ((1ULL << SQ_A2) | (1ULL << SQ_H2))
- };
-
// 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
+ // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
// happen in Chess960 games.
- const Value TrappedBishopA1H1Penalty = Value(100);
-
- // Bitboard masks for detecting trapped bishops on a1/h1 (a8/h8 for black):
- const Bitboard MaskA1H1[2] = {
- ((1ULL << SQ_A1) | (1ULL << SQ_H1)),
- ((1ULL << SQ_A8) | (1ULL << SQ_H8))
+ const Score TrappedBishopA1H1Penalty = make_score(100, 100);
+
+ // 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[] = {
+ (1ULL << SQ_C2) | (1ULL << SQ_D2) | (1ULL << SQ_E2) | (1ULL << SQ_F2) |
+ (1ULL << SQ_C3) | (1ULL << SQ_D3) | (1ULL << SQ_E3) | (1ULL << SQ_F3) |
+ (1ULL << SQ_C4) | (1ULL << SQ_D4) | (1ULL << SQ_E4) | (1ULL << SQ_F4),
+ (1ULL << SQ_C7) | (1ULL << SQ_D7) | (1ULL << SQ_E7) | (1ULL << SQ_F7) |
+ (1ULL << SQ_C6) | (1ULL << SQ_D6) | (1ULL << SQ_E6) | (1ULL << SQ_F6) |
+ (1ULL << SQ_C5) | (1ULL << SQ_D5) | (1ULL << SQ_E5) | (1ULL << SQ_F5)
};
- /// King safety constants and variables. The king safety scores are taken
- /// from the array SafetyTable[]. Various little "meta-bonuses" measuring
- /// the strength of the attack are added up into an integer, which is used
- /// as an index to SafetyTable[].
-
- // Attack weights for each piece type.
- const int QueenAttackWeight = 5;
- const int RookAttackWeight = 3;
- const int BishopAttackWeight = 2;
- const int KnightAttackWeight = 2;
-
- // Bonuses for safe checks for each piece type.
- int QueenContactCheckBonus = 4;
- int RookContactCheckBonus = 2;
- int QueenCheckBonus = 2;
- int RookCheckBonus = 1;
- int BishopCheckBonus = 1;
- int KnightCheckBonus = 1;
- int DiscoveredCheckBonus = 3;
-
- // Scan for queen contact mates?
- const bool QueenContactMates = true;
-
- // Bonus for having a mate threat.
- int MateThreatBonus = 3;
-
- // InitKingDanger[] contains bonuses based on the position of the defending
- // king.
- const int InitKingDanger[64] = {
+ // King danger constants and variables. The king danger scores are taken
+ // from the KingDangerTable[]. Various little "meta-bonuses" measuring
+ // the strength of the enemy attack are added up into an integer, which
+ // is used as an index to KingDangerTable[].
+ //
+ // KingAttackWeights[PieceType] contains king attack weights by piece type
+ const int KingAttackWeights[] = { 0, 0, 2, 2, 3, 5 };
+
+ // Bonuses for enemy's safe checks
+ const int QueenContactCheckBonus = 6;
+ const int RookContactCheckBonus = 4;
+ const int QueenCheckBonus = 3;
+ const int RookCheckBonus = 2;
+ const int BishopCheckBonus = 1;
+ const int KnightCheckBonus = 1;
+
+ // InitKingDanger[Square] contains penalties based on the position of the
+ // defending king, indexed by king's square (from white's point of view).
+ const int InitKingDanger[] = {
2, 0, 2, 5, 5, 2, 0, 2,
2, 2, 4, 8, 8, 4, 2, 2,
7, 10, 12, 12, 12, 12, 10, 7,
15, 15, 15, 15, 15, 15, 15, 15
};
- // SafetyTable[] contains the actual king safety scores. It is initialized
- // in init_safety().
- Value SafetyTable[100];
+ // KingDangerTable[Color][attackUnits] contains the actual king danger
+ // 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:
- PawnInfoTable *PawnTable[8] = {0, 0, 0, 0, 0, 0, 0, 0};
- MaterialInfoTable *MaterialTable[8] = {0, 0, 0, 0, 0, 0, 0, 0};
+ // 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];
- // Sizes of pawn and material hash tables:
- const int PawnTableSize = 16384;
- const int MaterialTableSize = 1024;
+ // Function prototypes
+ template<bool HasPopCnt>
+ Value do_evaluate(const Position& pos, Value& margin);
- // Array which gives the number of nonzero bits in an 8-bit integer:
- uint8_t BitCount8Bit[256];
+ template<Color Us, bool HasPopCnt>
+ void init_eval_info(const Position& pos, EvalInfo& ei);
- // Function prototypes:
- void evaluate_knight(const Position &p, Square s, Color us, EvalInfo &ei);
- void evaluate_bishop(const Position &p, Square s, Color us, EvalInfo &ei);
- void evaluate_rook(const Position &p, Square s, Color us, EvalInfo &ei);
- void evaluate_queen(const Position &p, Square s, Color us, EvalInfo &ei);
- void evaluate_king(const Position &p, Square s, Color us, EvalInfo &ei);
+ template<Color Us, bool HasPopCnt>
+ Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility);
- void evaluate_passed_pawns(const Position &pos, EvalInfo &ei);
- void evaluate_trapped_bishop_a7h7(const Position &pos, Square s, Color us,
- EvalInfo &ei);
- void evaluate_trapped_bishop_a1h1(const Position &pos, Square s, Color us,
- EvalInfo &ei);
+ template<Color Us, bool HasPopCnt>
+ Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]);
- inline Value apply_weight(Value v, int w);
- Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]);
+ template<Color Us>
+ Score evaluate_threats(const Position& pos, EvalInfo& ei);
- int count_1s_8bit(Bitboard b);
+ template<Color Us, bool HasPopCnt>
+ int evaluate_space(const Position& pos, EvalInfo& ei);
- int compute_weight(int uciWeight, int internalWeight);
- int weight_option(const std::string& opt, int weight);
- void init_safety();
+ template<Color Us>
+ Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
+
+ template<bool HasPopCnt>
+ 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, ScaleFactor sf);
+ Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
+ void init_safety();
}
//// Functions
////
-/// 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, EvalInfo &ei, int threadID) {
+/// Prefetches in pawn hash tables
- assert(pos.is_ok());
- assert(threadID >= 0 && threadID < THREAD_MAX);
+void prefetchPawn(Key key, int threadID) {
- memset(&ei, 0, sizeof(EvalInfo));
+ PawnTable[threadID]->prefetch(key);
+}
- // Initialize by reading the incrementally updated scores included in the
- // position object (material + piece square tables)
- ei.mgValue = pos.mg_value();
- ei.egValue = pos.eg_value();
- // Probe the material hash table
- ei.mi = MaterialTable[threadID]->get_material_info(pos);
- ei.mgValue += ei.mi->mg_value();
- ei.egValue += ei.mi->eg_value();
+/// 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& margin) {
- // 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);
+ return CpuHasPOPCNT ? do_evaluate<true>(pos, margin)
+ : do_evaluate<false>(pos, margin);
+}
- // After get_material_info() call that modifies them
- ScaleFactor factor[2];
- factor[WHITE] = ei.mi->scale_factor(pos, WHITE);
- factor[BLACK] = ei.mi->scale_factor(pos, BLACK);
+namespace {
- // Probe the pawn hash table
- ei.pi = PawnTable[threadID]->get_pawn_info(pos);
- ei.mgValue += apply_weight(ei.pi->mg_value(), WeightPawnStructureMidgame);
- ei.egValue += apply_weight(ei.pi->eg_value(), WeightPawnStructureEndgame);
-
- // Initialize king attack bitboards and king attack zones for both sides
- ei.attackedBy[WHITE][KING] = pos.piece_attacks<KING>(pos.king_square(WHITE));
- ei.attackedBy[BLACK][KING] = pos.piece_attacks<KING>(pos.king_square(BLACK));
- ei.kingZone[WHITE] = ei.attackedBy[BLACK][KING] | (ei.attackedBy[BLACK][KING] >> 8);
- ei.kingZone[BLACK] = ei.attackedBy[WHITE][KING] | (ei.attackedBy[WHITE][KING] << 8);
-
- // Initialize pawn attack bitboards for both sides
- ei.attackedBy[WHITE][PAWN] = ((pos.pawns(WHITE) << 9) & ~FileABB) | ((pos.pawns(WHITE) << 7) & ~FileHBB);
- ei.attackedBy[BLACK][PAWN] = ((pos.pawns(BLACK) >> 7) & ~FileABB) | ((pos.pawns(BLACK) >> 9) & ~FileHBB);
- ei.kingAttackersCount[WHITE] = count_1s_max_15(ei.attackedBy[WHITE][PAWN] & ei.attackedBy[BLACK][KING])/2;
- ei.kingAttackersCount[BLACK] = count_1s_max_15(ei.attackedBy[BLACK][PAWN] & ei.attackedBy[WHITE][KING])/2;
-
- // Evaluate pieces
- for (Color c = WHITE; c <= BLACK; c++)
- {
- // Knights
- for (int i = 0; i < pos.piece_count(c, KNIGHT); i++)
- evaluate_knight(pos, pos.piece_list(c, KNIGHT, i), c, ei);
+template<bool HasPopCnt>
+Value do_evaluate(const Position& pos, Value& margin) {
- // Bishops
- for (int i = 0; i < pos.piece_count(c, BISHOP); i++)
- evaluate_bishop(pos, pos.piece_list(c, BISHOP, i), c, ei);
+ EvalInfo ei;
+ Value margins[2];
+ Score mobilityWhite, mobilityBlack;
- // Rooks
- for (int i = 0; i < pos.piece_count(c, ROOK); i++)
- evaluate_rook(pos, pos.piece_list(c, ROOK, i), c, ei);
+ assert(pos.is_ok());
+ assert(pos.thread() >= 0 && pos.thread() < MAX_THREADS);
+ assert(!pos.is_check());
- // Queens
- for(int i = 0; i < pos.piece_count(c, QUEEN); i++)
- evaluate_queen(pos, pos.piece_list(c, QUEEN, i), c, ei);
+ // Initialize value by reading the incrementally updated scores included
+ // in the position object (material + piece square tables).
+ Score bonus = pos.value();
- // Special pattern: trapped bishops on a7/h7/a2/h2
- Bitboard b = pos.bishops(c) & MaskA7H7[c];
- while (b)
- {
- Square s = pop_1st_bit(&b);
- evaluate_trapped_bishop_a7h7(pos, s, c, ei);
- }
+ // 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;
- // Special pattern: trapped bishops on a1/h1/a8/h8 in Chess960:
- if (Chess960)
- {
- b = pos.bishops(c) & MaskA1H1[c];
- while (b)
- {
- Square s = pop_1st_bit(&b);
- evaluate_trapped_bishop_a1h1(pos, s, c, ei);
- }
- }
+ // Probe the material hash table
+ MaterialInfo* mi = MaterialTable[pos.thread()]->get_material_info(pos);
+ bonus += mi->material_value();
- // Sum up all attacked squares
- ei.attackedBy[c][0] = ei.attackedBy[c][PAWN] | ei.attackedBy[c][KNIGHT]
- | ei.attackedBy[c][BISHOP] | ei.attackedBy[c][ROOK]
- | ei.attackedBy[c][QUEEN] | ei.attackedBy[c][KING];
+ // If we have a specialized evaluation function for the current material
+ // configuration, call it and return.
+ if (mi->specialized_eval_exists())
+ {
+ margin = VALUE_ZERO;
+ return mi->evaluate(pos);
}
- // Kings. Kings are evaluated after all other pieces for both sides,
- // because we need complete attack information for all pieces when computing
- // the king safety evaluation.
- for (Color c = WHITE; c <= BLACK; c++)
- evaluate_king(pos, pos.king_square(c), c, ei);
+ // Probe the pawn hash table
+ ei.pi = PawnTable[pos.thread()]->get_pawn_info(pos);
+ bonus += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
- // Evaluate passed pawns. We evaluate passed pawns for both sides at once,
- // because we need to know which side promotes first in positions where
- // both sides have an unstoppable passed pawn.
- if (ei.pi->passed_pawns())
- evaluate_passed_pawns(pos, ei);
+ // Initialize attack and king safety bitboards
+ init_eval_info<WHITE, HasPopCnt>(pos, ei);
+ init_eval_info<BLACK, HasPopCnt>(pos, ei);
- Phase phase = pos.game_phase();
+ // Evaluate pieces and mobility
+ bonus += evaluate_pieces_of_color<WHITE, HasPopCnt>(pos, ei, mobilityWhite)
+ - evaluate_pieces_of_color<BLACK, HasPopCnt>(pos, ei, mobilityBlack);
- // Middle-game specific evaluation terms
- if (phase > PHASE_ENDGAME)
- {
- // Pawn storms in positions with opposite castling.
- if ( square_file(pos.king_square(WHITE)) >= FILE_E
- && square_file(pos.king_square(BLACK)) <= FILE_D)
+ bonus += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
+
+ // Evaluate kings after all other pieces because we need complete attack
+ // information when computing the king safety evaluation.
+ bonus += evaluate_king<WHITE, HasPopCnt>(pos, ei, margins)
+ - evaluate_king<BLACK, HasPopCnt>(pos, ei, margins);
+
+ // Evaluate tactical threats, we need full attack information including king
+ bonus += evaluate_threats<WHITE>(pos, ei)
+ - evaluate_threats<BLACK>(pos, ei);
- ei.mgValue += ei.pi->queenside_storm_value(WHITE)
- - ei.pi->kingside_storm_value(BLACK);
+ // Evaluate passed pawns, we need full attack information including king
+ bonus += evaluate_passed_pawns<WHITE>(pos, ei)
+ - evaluate_passed_pawns<BLACK>(pos, ei);
- else if ( square_file(pos.king_square(WHITE)) <= FILE_D
- && square_file(pos.king_square(BLACK)) >= FILE_E)
+ // 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))
+ bonus += evaluate_unstoppable_pawns<HasPopCnt>(pos, ei);
- ei.mgValue += ei.pi->kingside_storm_value(WHITE)
- - ei.pi->queenside_storm_value(BLACK);
+ // Evaluate space for both sides, only in middle-game.
+ if (mi->space_weight())
+ {
+ int s = evaluate_space<WHITE, HasPopCnt>(pos, ei) - evaluate_space<BLACK, HasPopCnt>(pos, ei);
+ bonus += apply_weight(make_score(s * mi->space_weight(), 0), Weights[Space]);
}
- // Mobility
- ei.mgValue += apply_weight(ei.mgMobility, WeightMobilityMidgame);
- ei.egValue += apply_weight(ei.egMobility, WeightMobilityEndgame);
+ // Scale winning side if position is more drawish that what it appears
+ ScaleFactor sf = eg_value(bonus) > VALUE_DRAW ? mi->scale_factor(pos, WHITE)
+ : mi->scale_factor(pos, BLACK);
+ Phase phase = mi->game_phase();
// If we don't already have an unusual scale factor, check for opposite
- // colored bishop endgames, and use a lower scale for those:
+ // colored bishop endgames, and use a lower scale for those.
if ( phase < PHASE_MIDGAME
&& pos.opposite_colored_bishops()
- && ( (factor[WHITE] == SCALE_FACTOR_NORMAL && ei.egValue > Value(0))
- || (factor[BLACK] == SCALE_FACTOR_NORMAL && ei.egValue < Value(0))))
+ && 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, and
- // return
- Color stm = pos.side_to_move();
-
- Value v = Sign[stm] * scale_by_game_phase(ei.mgValue, ei.egValue, phase, factor);
-
- return (ei.mateThreat[stm] == MOVE_NONE ? v : 8 * QueenValueMidgame - v);
+ // Interpolate between the middle game and the endgame score
+ margin = margins[pos.side_to_move()];
+ Value v = scale_by_game_phase(bonus, phase, sf);
+ return pos.side_to_move() == WHITE ? v : -v;
}
+} // namespace
-/// quick_evaluate() does a very approximate evaluation of the current position.
-/// It currently considers only material and piece square table scores. Perhaps
-/// we should add scores from the pawn and material hash tables?
-
-Value quick_evaluate(const Position &pos) {
-
- assert(pos.is_ok());
- static const
- ScaleFactor sf[2] = {SCALE_FACTOR_NORMAL, SCALE_FACTOR_NORMAL};
-
- Value mgv = pos.mg_value();
- Value egv = pos.eg_value();
- Phase ph = pos.game_phase();
- Color stm = pos.side_to_move();
-
- return Sign[stm] * scale_by_game_phase(mgv, egv, ph, sf);
-}
-
-
-/// init_eval() initializes various tables used by the evaluation function.
+/// init_eval() initializes various tables used by the evaluation function
void init_eval(int threads) {
- assert(threads <= THREAD_MAX);
+ assert(threads <= MAX_THREADS);
- for (int i = 0; i < THREAD_MAX; i++)
+ 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(PawnTableSize);
- if (!MaterialTable[i])
- MaterialTable[i] = new MaterialInfoTable(MaterialTableSize);
- }
+ if (i >= threads)
+ {
+ delete PawnTable[i];
+ delete MaterialTable[i];
+ PawnTable[i] = NULL;
+ MaterialTable[i] = NULL;
+ continue;
+ }
+ if (!PawnTable[i])
+ PawnTable[i] = new PawnInfoTable();
- for (Bitboard b = 0ULL; b < 256ULL; b++)
- BitCount8Bit[b] = count_1s(b);
+ if (!MaterialTable[i])
+ MaterialTable[i] = new MaterialInfoTable();
+ }
}
-/// quit_eval() releases heap-allocated memory at program termination.
+/// quit_eval() releases heap-allocated memory at program termination
void quit_eval() {
- for (int i = 0; i < THREAD_MAX; i++)
- {
- delete PawnTable[i];
- delete MaterialTable[i];
- }
+ init_eval(0);
}
-/// read_weights() reads evaluation weights from the corresponding UCI
-/// parameters.
+/// read_weights() reads evaluation weights from the corresponding UCI parameters
-void read_weights(Color us) {
+void read_evaluation_uci_options(Color us) {
- WeightMobilityMidgame = weight_option("Mobility (Middle Game)", WeightMobilityMidgameInternal);
- WeightMobilityEndgame = weight_option("Mobility (Endgame)", WeightMobilityEndgameInternal);
- WeightPawnStructureMidgame = weight_option("Pawn Structure (Middle Game)", WeightPawnStructureMidgameInternal);
- WeightPawnStructureEndgame = weight_option("Pawn Structure (Endgame)", WeightPawnStructureEndgameInternal);
- WeightPassedPawnsMidgame = weight_option("Passed Pawns (Middle Game)", WeightPassedPawnsMidgameInternal);
- WeightPassedPawnsEndgame = weight_option("Passed Pawns (Endgame)", WeightPassedPawnsEndgameInternal);
+ // 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);
- Color them = opposite_color(us);
+ 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]);
- WeightKingSafety[us] = weight_option("Cowardice", WeightKingSafetyInternal);
- WeightKingSafety[them] = weight_option("Aggressiveness", WeightKingOppSafetyInternal);
+ // 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"].value<bool>())
+ Weights[kingDangerUs] = Weights[kingDangerThem] = (Weights[kingDangerUs] + Weights[kingDangerThem]) / 2;
init_safety();
}
namespace {
- // evaluate_common() computes terms common to all pieces attack
+ // 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_eval_info(const Position& pos, EvalInfo& ei) {
- int evaluate_common(const Position&p, const Bitboard& b, Color us, EvalInfo& ei,
- int AttackWeight, const Value* mgBonus, const Value* egBonus,
- Square s = SQ_NONE, const Value* OutpostBonus = NULL) {
+ const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
- Color them = opposite_color(us);
+ Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
+ ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
- // King attack
- if (b & ei.kingZone[us])
+ // 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.kingAttackersCount[us]++;
- ei.kingAttackersWeight[us] += AttackWeight;
- Bitboard bb = (b & ei.attackedBy[them][KING]);
- if (bb)
- ei.kingAdjacentZoneAttacksCount[us] += count_1s_max_15(bb);
- }
+ ei.kingZone[Us] = (b | (Us == WHITE ? b >> 8 : b << 8));
+ b &= ei.attackedBy[Us][PAWN];
+ ei.kingAttackersCount[Us] = b ? count_1s<Max15>(b) / 2 : 0;
+ ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
+ } else
+ ei.kingZone[Us] = ei.kingAttackersCount[Us] = 0;
+ }
+
+
+ // evaluate_outposts() evaluates bishop and knight outposts squares
- // Mobility
- int mob = count_1s_max_15(b & ~p.pieces_of_color(us));
- ei.mgMobility += Sign[us] * mgBonus[mob];
- ei.egMobility += Sign[us] * egBonus[mob];
+ template<PieceType Piece, Color Us>
+ Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
- // Bishop and Knight outposts
- if (!OutpostBonus || !p.square_is_weak(s, them))
- return mob;
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+
+ assert (Piece == BISHOP || Piece == KNIGHT);
// Initial bonus based on square
- Value v, bonus;
- v = bonus = OutpostBonus[relative_square(us, s)];
+ 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 (v && (p.pawn_attacks(them, s) & p.pawns(us)))
+ // no minor piece which can exchange the outpost piece.
+ if (bonus && bit_is_set(ei.attackedBy[Us][PAWN], s))
{
- bonus += v / 2;
- if ( p.piece_count(them, KNIGHT) == 0
- && (SquaresByColorBB[square_color(s)] & p.bishops(them)) == EmptyBoardBB)
- bonus += v;
+ if ( pos.pieces(KNIGHT, Them) == EmptyBoardBB
+ && (SquaresByColorBB[square_color(s)] & pos.pieces(BISHOP, Them)) == EmptyBoardBB)
+ bonus += bonus + bonus / 2;
+ else
+ bonus += bonus / 2;
}
- ei.mgValue += Sign[us] * bonus;
- ei.egValue += Sign[us] * bonus;
- return mob;
+ return make_score(bonus, bonus);
}
- // evaluate_knight() assigns bonuses and penalties to a knight of a given
- // color on a given square.
+ // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
- void evaluate_knight(const Position &p, Square s, Color us, EvalInfo &ei) {
+ template<PieceType Piece, Color Us, bool HasPopCnt>
+ Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
- Bitboard b = p.piece_attacks<KNIGHT>(s);
- ei.attackedBy[us][KNIGHT] |= b;
+ Bitboard b;
+ Square s, ksq;
+ int mob;
+ File f;
+ Score bonus = SCORE_ZERO;
- // King attack, mobility and outposts
- evaluate_common(p, b, us, ei, KnightAttackWeight, MidgameKnightMobilityBonus,
- EndgameKnightMobilityBonus, s, KnightOutpostBonus);
- }
+ const BitCountType Full = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64 : CNT32;
+ const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Square* ptr = pos.piece_list_begin(Us, Piece);
+ ei.attackedBy[Us][Piece] = EmptyBoardBB;
- // evaluate_bishop() assigns bonuses and penalties to a bishop of a given
- // color on a given square.
-
- void evaluate_bishop(const Position &p, Square s, Color us, EvalInfo &ei) {
-
- Bitboard b = bishop_attacks_bb(s, p.occupied_squares() & ~p.queens(us));
- ei.attackedBy[us][BISHOP] |= b;
-
- // King attack, mobility and outposts
- evaluate_common(p, b, us, ei, BishopAttackWeight, MidgameBishopMobilityBonus,
- EndgameBishopMobilityBonus, s, BishopOutpostBonus);
- }
-
+ while ((s = *ptr++) != 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));
+ else if (Piece == ROOK)
+ b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
+ else
+ assert(false);
- // evaluate_rook() assigns bonuses and penalties to a rook of a given
- // color on a given square.
+ // Update attack info
+ ei.attackedBy[Us][Piece] |= b;
- void evaluate_rook(const Position &p, Square s, Color us, EvalInfo &ei) {
+ // King attacks
+ if (b & ei.kingZone[Us])
+ {
+ ei.kingAttackersCount[Us]++;
+ ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
+ Bitboard bb = (b & ei.attackedBy[Them][KING]);
+ if (bb)
+ ei.kingAdjacentZoneAttacksCount[Us] += count_1s<Max15>(bb);
+ }
- //Bitboard b = p.rook_attacks(s);
- Bitboard b = rook_attacks_bb(s, p.occupied_squares() & ~p.rooks_and_queens(us));
- ei.attackedBy[us][ROOK] |= b;
+ // Mobility
+ mob = (Piece != QUEEN ? count_1s<Max15>(b & mobilityArea)
+ : count_1s<Full >(b & mobilityArea));
- // King attack and mobility
- int mob = evaluate_common(p, b, us, ei, RookAttackWeight, MidgameRookMobilityBonus,
- EndgameRookMobilityBonus);
+ mobility += MobilityBonus[Piece][mob];
- // Rook on 7th rank
- Color them = opposite_color(us);
+ // 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 ( relative_rank(us, s) == RANK_7
- && relative_rank(us, p.king_square(them)) == RANK_8)
- {
- ei.mgValue += Sign[us] * MidgameRookOn7thBonus;
- ei.egValue += Sign[us] * EndgameRookOn7thBonus;
- }
+ // Bishop and knight outposts squares
+ if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Us))
+ bonus += evaluate_outposts<Piece, Us>(pos, ei, s);
- // Open and half-open files
- File f = square_file(s);
- if (ei.pi->file_is_half_open(us, f))
- {
- if (ei.pi->file_is_half_open(them, f))
+ // 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)
{
- ei.mgValue += Sign[us] * RookOpenFileBonus;
- ei.egValue += Sign[us] * RookOpenFileBonus;
+ bonus += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
}
- else
+
+ // Special extra evaluation for bishops
+ if (Piece == BISHOP && pos.is_chess960())
{
- ei.mgValue += Sign[us] * RookHalfOpenFileBonus;
- ei.egValue += Sign[us] * RookHalfOpenFileBonus;
+ // 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) + (square_file(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)))
+ bonus -= 2*TrappedBishopA1H1Penalty;
+ else if (pos.piece_on(s + 2*d) == make_piece(Us, PAWN))
+ bonus -= TrappedBishopA1H1Penalty;
+ else
+ bonus -= TrappedBishopA1H1Penalty / 2;
+ }
+ }
}
- }
- // Penalize rooks which are trapped inside a king. Penalize more if
- // king has lost right to castle
- if (mob > 6 || ei.pi->file_is_half_open(us, f))
- return;
+ // Special extra evaluation for rooks
+ if (Piece == ROOK)
+ {
+ // Open and half-open files
+ f = square_file(s);
+ if (ei.pi->file_is_half_open(Us, f))
+ {
+ if (ei.pi->file_is_half_open(Them, f))
+ bonus += RookOpenFileBonus;
+ else
+ bonus += RookHalfOpenFileBonus;
+ }
+
+ // Penalize rooks which are trapped inside a king. Penalize more if
+ // king has lost right to castle.
+ if (mob > 6 || ei.pi->file_is_half_open(Us, f))
+ continue;
- Square ksq = p.king_square(us);
+ 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)))
- {
- // 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)))
- ei.mgValue -= p.can_castle(us)? Sign[us] * ((TrappedRookPenalty - mob * 16) / 2)
- : Sign[us] * (TrappedRookPenalty - mob * 16);
- }
- 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)))
- {
- // 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)))
- ei.mgValue -= p.can_castle(us)? Sign[us] * ((TrappedRookPenalty - mob * 16) / 2)
- : Sign[us] * (TrappedRookPenalty - mob * 16);
+ if ( square_file(ksq) >= FILE_E
+ && square_file(s) > square_file(ksq)
+ && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(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
+ : (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)))
+ {
+ // 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
+ : (TrappedRookPenalty - mob * 16), 0);
+ }
+ }
}
+ return bonus;
}
- // evaluate_queen() assigns bonuses and penalties to a queen of a given
- // color on a given square.
+ // evaluate_threats<>() assigns bonuses according to the type of attacking piece
+ // and the type of attacked one.
- void evaluate_queen(const Position &p, Square s, Color us, EvalInfo &ei) {
+ template<Color Us>
+ Score evaluate_threats(const Position& pos, EvalInfo& ei) {
- Bitboard b = p.piece_attacks<QUEEN>(s);
- ei.attackedBy[us][QUEEN] |= b;
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
- // King attack and mobility
- evaluate_common(p, b, us, ei, QueenAttackWeight, MidgameQueenMobilityBonus,
- EndgameQueenMobilityBonus);
+ Bitboard b;
+ Score bonus = SCORE_ZERO;
- // Queen on 7th rank
- Color them = opposite_color(us);
+ // Enemy pieces not defended by a pawn and under our attack
+ Bitboard weakEnemies = pos.pieces_of_color(Them)
+ & ~ei.attackedBy[Them][PAWN]
+ & ei.attackedBy[Us][0];
+ if (!weakEnemies)
+ return SCORE_ZERO;
- if ( relative_rank(us, s) == RANK_7
- && relative_rank(us, p.king_square(them)) == RANK_8)
+ // Add bonus according to type of attacked enemy piece and to the
+ // type of attacking piece, from knights to queens. Kings are not
+ // considered because are already handled in king evaluation.
+ for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
{
- ei.mgValue += Sign[us] * MidgameQueenOn7thBonus;
- ei.egValue += Sign[us] * EndgameQueenOn7thBonus;
+ b = ei.attackedBy[Us][pt1] & weakEnemies;
+ if (b)
+ for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
+ if (b & pos.pieces(pt2))
+ bonus += ThreatBonus[pt1][pt2];
}
+ return bonus;
}
- inline Bitboard shiftRowsDown(const Bitboard& b, int num) {
- return b >> (num << 3);
+ // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
+ // pieces of a given color.
+
+ template<Color Us, bool HasPopCnt>
+ Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) {
+
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+
+ Score bonus = mobility = SCORE_ZERO;
+
+ // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
+ const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces_of_color(Us));
+
+ bonus += evaluate_pieces<KNIGHT, Us, HasPopCnt>(pos, ei, mobility, mobilityArea);
+ bonus += evaluate_pieces<BISHOP, Us, HasPopCnt>(pos, ei, mobility, mobilityArea);
+ bonus += evaluate_pieces<ROOK, Us, HasPopCnt>(pos, ei, mobility, mobilityArea);
+ bonus += evaluate_pieces<QUEEN, Us, HasPopCnt>(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;
}
- // evaluate_king() assigns bonuses and penalties to a king of a given
- // color on a given square.
- void evaluate_king(const Position &p, Square s, Color us, EvalInfo &ei) {
+ // evaluate_king<>() assigns bonuses and penalties to a king of a given color
- int shelter = 0, sign = Sign[us];
+ template<Color Us, bool HasPopCnt>
+ Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
- // King shelter
- if (relative_rank(us, s) <= RANK_4)
- {
- Bitboard pawns = p.pawns(us) & this_and_neighboring_files_bb(s);
- Rank r = square_rank(s);
- for (int i = 1; i < 4; i++)
- shelter += count_1s_8bit(shiftRowsDown(pawns, r+i*sign)) * (128>>i);
+ const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
- ei.mgValue += sign * Value(shelter);
- }
+ Bitboard undefended, b, b1, b2, safe;
+ int attackUnits;
+ const Square ksq = pos.king_square(Us);
- // King safety. This is quite complicated, and is almost certainly far
- // from optimally tuned.
- Color them = opposite_color(us);
+ // King shelter
+ Score bonus = ei.pi->king_shelter<Us>(pos, ksq);
- if ( p.piece_count(them, QUEEN) >= 1
- && ei.kingAttackersCount[them] >= 2
- && p.non_pawn_material(them) >= QueenValueMidgame + RookValueMidgame
- && ei.kingAdjacentZoneAttacksCount[them])
+ // King safety. This is quite complicated, and is almost certainly far
+ // from optimally tuned.
+ if ( ei.kingAttackersCount[Them] >= 2
+ && ei.kingAdjacentZoneAttacksCount[Them])
{
- // Is it the attackers turn to move?
- bool sente = (them == p.side_to_move());
-
- // Find the attacked squares around the king which has no defenders
- // apart from the king itself
- Bitboard undefended =
- ei.attacked_by(them) & ~ei.attacked_by(us, PAWN)
- & ~ei.attacked_by(us, KNIGHT) & ~ei.attacked_by(us, BISHOP)
- & ~ei.attacked_by(us, ROOK) & ~ei.attacked_by(us, QUEEN)
- & ei.attacked_by(us, KING);
-
- Bitboard occ = p.occupied_squares(), b, b2;
-
- // Initialize the 'attackUnits' variable, which is used later on as an
- // index to the SafetyTable[] array. The initial is based on the number
- // and types of the attacking pieces, the number of attacked and
- // undefended squares around the king, the square of the king, and the
- // quality of the pawn shelter.
- int attackUnits =
- Min((ei.kingAttackersCount[them] * ei.kingAttackersWeight[them]) / 2, 25)
- + (ei.kingAdjacentZoneAttacksCount[them] + count_1s_max_15(undefended)) * 3
- + InitKingDanger[relative_square(us, s)] - shelter / 32;
-
- // Analyse safe queen contact checks
- b = undefended & ei.attacked_by(them, QUEEN) & ~p.pieces_of_color(them);
- if (b)
- {
- Bitboard attackedByOthers =
- ei.attacked_by(them, PAWN) | ei.attacked_by(them, KNIGHT)
- | ei.attacked_by(them, BISHOP) | ei.attacked_by(them, ROOK);
-
- b &= attackedByOthers;
+ // 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];
+ undefended &= ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
+ | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
+ | ei.attackedBy[Us][QUEEN]);
+
+ // Initialize the 'attackUnits' variable, which is used later on as an
+ // index to the KingDangerTable[] array. The initial value is based on
+ // the number and types of the enemy's attacking pieces, the number of
+ // attacked and undefended squares around our king, the square of the
+ // king, and the quality of the pawn shelter.
+ attackUnits = Min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
+ + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + count_1s<Max15>(undefended))
+ + InitKingDanger[relative_square(Us, ksq)]
+ - 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);
if (b)
{
- // The bitboard b now contains the squares available for safe queen
- // contact checks.
- int count = count_1s_max_15(b);
- attackUnits += QueenContactCheckBonus * count * (sente ? 2 : 1);
-
- // Is there a mate threat?
- if (QueenContactMates && !p.is_check())
- {
- Bitboard escapeSquares =
- p.piece_attacks<KING>(s) & ~p.pieces_of_color(us) & ~attackedByOthers;
-
- while (b)
- {
- Square from, to = pop_1st_bit(&b);
- if (!(escapeSquares & ~queen_attacks_bb(to, occ & ClearMaskBB[s])))
- {
- // We have a mate, unless the queen is pinned or there
- // is an X-ray attack through the queen.
- for (int i = 0; i < p.piece_count(them, QUEEN); i++)
- {
- from = p.piece_list(them, QUEEN, i);
- if ( bit_is_set(p.piece_attacks<QUEEN>(from), to)
- && !bit_is_set(p.pinned_pieces(them), from)
- && !(rook_attacks_bb(to, occ & ClearMaskBB[from]) & p.rooks_and_queens(us))
- && !(rook_attacks_bb(to, occ & ClearMaskBB[from]) & p.rooks_and_queens(us)))
-
- ei.mateThreat[them] = make_move(from, to);
- }
- }
- }
- }
+ // ...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<Max15>(b)
+ * (Them == pos.side_to_move() ? 2 : 1);
}
- }
- // Analyse safe rook contact checks:
- if (RookContactCheckBonus)
- {
- b = undefended & ei.attacked_by(them, ROOK) & ~p.pieces_of_color(them);
- if (b)
- {
- Bitboard attackedByOthers =
- ei.attacked_by(them, PAWN) | ei.attacked_by(them, KNIGHT)
- | ei.attacked_by(them, BISHOP) | ei.attacked_by(them, QUEEN);
-
- b &= attackedByOthers;
- if (b)
- {
- int count = count_1s_max_15(b);
- attackUnits += (RookContactCheckBonus * count * (sente? 2 : 1));
- }
- }
- }
- // Analyse safe distance checks:
- if (QueenCheckBonus > 0 || RookCheckBonus > 0)
- {
- b = p.piece_attacks<ROOK>(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
- // Queen checks
- b2 = b & ei.attacked_by(them, QUEEN);
- if( b2)
- attackUnits += QueenCheckBonus * count_1s_max_15(b2);
+ // 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_of_color(Them);
- // Rook checks
- b2 = b & ei.attacked_by(them, ROOK);
- if (b2)
- attackUnits += RookCheckBonus * count_1s_max_15(b2);
- }
- if (QueenCheckBonus > 0 || BishopCheckBonus > 0)
- {
- b = p.piece_attacks<BISHOP>(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
+ // Consider only squares where the enemy rook gives check
+ b &= RookPseudoAttacks[ksq];
- // Queen checks
- b2 = b & ei.attacked_by(them, QUEEN);
- if (b2)
- attackUnits += QueenCheckBonus * count_1s_max_15(b2);
+ 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
+ * count_1s<Max15>(b)
+ * (Them == pos.side_to_move() ? 2 : 1);
+ }
- // Bishop checks
- b2 = b & ei.attacked_by(them, BISHOP);
- if (b2)
- attackUnits += BishopCheckBonus * count_1s_max_15(b2);
- }
- if (KnightCheckBonus > 0)
- {
- b = p.piece_attacks<KNIGHT>(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
+ // Analyse enemy's safe distance checks for sliders and knights
+ safe = ~(pos.pieces_of_color(Them) | ei.attackedBy[Us][0]);
- // Knight checks
- b2 = b & ei.attacked_by(them, KNIGHT);
- if (b2)
- attackUnits += KnightCheckBonus * count_1s_max_15(b2);
- }
+ b1 = pos.attacks_from<ROOK>(ksq) & safe;
+ b2 = pos.attacks_from<BISHOP>(ksq) & safe;
- // Analyse discovered checks (only for non-pawns right now, consider
- // adding pawns later).
- if (DiscoveredCheckBonus)
- {
- b = p.discovered_check_candidates(them) & ~p.pawns();
+ // Enemy queen safe checks
+ b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
if (b)
- attackUnits += DiscoveredCheckBonus * count_1s_max_15(b) * (sente? 2 : 1);
- }
+ attackUnits += QueenCheckBonus * count_1s<Max15>(b);
+
+ // Enemy rooks safe checks
+ b = b1 & ei.attackedBy[Them][ROOK];
+ if (b)
+ attackUnits += RookCheckBonus * count_1s<Max15>(b);
- // Has a mate threat been found? We don't do anything here if the
- // side with the mating move is the side to move, because in that
- // case the mating side will get a huge bonus at the end of the main
- // evaluation function instead.
- if (ei.mateThreat[them] != MOVE_NONE)
- attackUnits += MateThreatBonus;
-
- // Ensure that attackUnits is between 0 and 99, in order to avoid array
- // out of bounds errors:
- if (attackUnits < 0)
- attackUnits = 0;
-
- if (attackUnits >= 100)
- attackUnits = 99;
-
- // Finally, extract the king safety score from the SafetyTable[] array.
- // Add the score to the evaluation, and also to ei.futilityMargin. The
- // reason for adding the king safety score to the futility margin is
- // that the king safety scores can sometimes be very big, and that
- // capturing a single attacking piece can therefore result in a score
- // change far bigger than the value of the captured piece.
- Value v = apply_weight(SafetyTable[attackUnits], WeightKingSafety[us]);
-
- ei.mgValue -= sign * v;
-
- if (us == p.side_to_move())
- ei.futilityMargin += v;
+ // Enemy bishops safe checks
+ b = b2 & ei.attackedBy[Them][BISHOP];
+ if (b)
+ attackUnits += BishopCheckBonus * count_1s<Max15>(b);
+
+ // Enemy knights safe checks
+ b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
+ if (b)
+ attackUnits += KnightCheckBonus * count_1s<Max15>(b);
+
+ // To index KingDangerTable[] attackUnits must be in [0, 99] range
+ attackUnits = Min(99, 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]);
}
+ return bonus;
}
- // evaluate_passed_pawns() evaluates the passed pawns for both sides.
+ // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
+
+ template<Color Us>
+ Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
- void evaluate_passed_pawns(const Position &pos, EvalInfo &ei) {
- bool hasUnstoppable[2] = {false, false};
- int movesToGo[2] = {100, 100};
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
- for(Color us = WHITE; us <= BLACK; us++) {
- Color them = opposite_color(us);
- Square ourKingSq = pos.king_square(us);
- Square theirKingSq = pos.king_square(them);
- Bitboard b = ei.pi->passed_pawns() & pos.pawns(us), b2, b3, b4;
+ Score bonus = SCORE_ZERO;
+ Bitboard squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
+ Bitboard b = ei.pi->passed_pawns(Us);
- while(b) {
+ if (!b)
+ return SCORE_ZERO;
+
+ do {
Square s = pop_1st_bit(&b);
- assert(pos.piece_on(s) == pawn_of_color(us));
- assert(pos.pawn_is_passed(us, s));
-
- int r = int(relative_rank(us, s) - RANK_2);
- int tr = Max(0, r * (r-1));
- Square blockSq = s + pawn_push(us);
-
- // Base bonus based on rank:
- Value mbonus = Value(20 * tr);
- Value ebonus = Value(10 + r * r * 10);
-
- // Adjust bonus based on king proximity:
- ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr);
- ebonus -=
- Value(square_distance(ourKingSq, blockSq + pawn_push(us)) * 1 * tr);
- ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr);
-
- // If the pawn is free to advance, increase bonus:
- if(pos.square_is_empty(blockSq)) {
-
- b2 = squares_in_front_of(us, s);
- b3 = b2 & ei.attacked_by(them);
- b4 = b2 & ei.attacked_by(us);
- if((b2 & pos.pieces_of_color(them)) == EmptyBoardBB) {
- // There are no enemy pieces in the pawn's path! Are any of the
- // squares in the pawn's path attacked by the enemy?
- if(b3 == EmptyBoardBB)
- // No enemy attacks, huge bonus!
- ebonus += Value(tr * ((b2 == b4)? 17 : 15));
- else
- // OK, there are enemy attacks. 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 * (((b3 & b4) == b3)? 13 : 8));
- }
- else {
- // There are some enemy pieces in the pawn's path. While this is
- // sad, we still assign a moderate bonus if all squares in the path
- // which are either occupied by or attacked by enemy pieces are
- // also attacked by us.
- if(((b3 | (b2 & pos.pieces_of_color(them))) & ~b4) == EmptyBoardBB)
- ebonus += Value(tr * 6);
- }
- // At last, add a small bonus when there are no *friendly* pieces
- // in the pawn's path:
- if((b2 & pos.pieces_of_color(us)) == EmptyBoardBB)
- ebonus += Value(tr);
- }
- // If the pawn is supported by a friendly pawn, increase bonus.
- b2 = pos.pawns(us) & neighboring_files_bb(s);
- if(b2 & rank_bb(s))
- ebonus += Value(r * 20);
- else if(pos.pawn_attacks(them, s) & b2)
- ebonus += Value(r * 12);
-
- // If the other side has only a king, check whether the pawn is
- // unstoppable:
- if(pos.non_pawn_material(them) == Value(0)) {
- Square qsq;
- int d;
-
- qsq = relative_square(us, make_square(square_file(s), RANK_8));
- d = square_distance(s, qsq) - square_distance(theirKingSq, qsq)
- + ((us == pos.side_to_move())? 0 : 1);
-
- if(d < 0) {
- int mtg = RANK_8 - relative_rank(us, s);
- int blockerCount =
- count_1s_max_15(squares_in_front_of(us,s)&pos.occupied_squares());
- mtg += blockerCount;
- d += blockerCount;
- if(d < 0) {
- hasUnstoppable[us] = true;
- movesToGo[us] = Min(movesToGo[us], mtg);
+ assert(pos.pawn_is_passed(Us, s));
+
+ int r = int(relative_rank(Us, s) - RANK_2);
+ int rr = r * (r - 1);
+
+ // Base bonus based on rank
+ Value mbonus = Value(20 * rr);
+ Value ebonus = Value(10 * (rr + r + 1));
+
+ if (rr)
+ {
+ Square blockSq = s + pawn_push(Us);
+
+ // Adjust bonus based on kings proximity
+ ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 3 * rr);
+ ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
+ ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 6 * rr);
+
+ // If the pawn is free to advance, increase bonus
+ if (pos.square_is_empty(blockSq))
+ {
+ squaresToQueen = squares_in_front_of(Us, s);
+ defendedSquares = squaresToQueen & ei.attackedBy[Us][0];
+
+ // 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_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));
+
+ // 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(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(rr * ((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(rr);
}
- }
- }
- // 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
+ } // 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);
+ 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(square_file(s) == FILE_A || square_file(s) == FILE_H) {
- if(pos.non_pawn_material(them) == KnightValueMidgame
- && pos.piece_count(them, KNIGHT) == 1)
- ebonus += ebonus / 4;
- else if(pos.rooks_and_queens(them))
- ebonus -= ebonus / 4;
+ if (square_file(s) == FILE_A || square_file(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);
- // Add the scores for this pawn to the middle game and endgame eval.
- ei.mgValue += apply_weight(Sign[us] * mbonus, WeightPassedPawnsMidgame);
- ei.egValue += apply_weight(Sign[us] * ebonus, WeightPassedPawnsEndgame);
- }
- }
+ } while (b);
- // Does either side have an unstoppable passed pawn?
- if(hasUnstoppable[WHITE] && !hasUnstoppable[BLACK])
- ei.egValue += UnstoppablePawnValue - Value(0x40 * movesToGo[WHITE]);
- else if(hasUnstoppable[BLACK] && !hasUnstoppable[WHITE])
- ei.egValue -= UnstoppablePawnValue - Value(0x40 * movesToGo[BLACK]);
- else if(hasUnstoppable[BLACK] && hasUnstoppable[WHITE]) {
- // Both sides have unstoppable pawns! Try to find out who queens
- // first. We begin by transforming 'movesToGo' to the number of
- // plies until the pawn queens for both sides:
- movesToGo[WHITE] *= 2;
- movesToGo[BLACK] *= 2;
- movesToGo[pos.side_to_move()]--;
-
- // If one side queens at least three plies before the other, that
- // side wins:
- if(movesToGo[WHITE] <= movesToGo[BLACK] - 3)
- ei.egValue += UnstoppablePawnValue - Value(0x40 * (movesToGo[WHITE]/2));
- else if(movesToGo[BLACK] <= movesToGo[WHITE] - 3)
- ei.egValue -= UnstoppablePawnValue - Value(0x40 * (movesToGo[BLACK]/2));
-
- // We could also add some rules about the situation when one side
- // queens exactly one ply before the other: Does the first queen
- // check the opponent's king, or attack the opponent's queening square?
- // This is slightly tricky to get right, because it is possible that
- // the opponent's king has moved somewhere before the first pawn queens.
- }
+ // Add the scores to the middle game and endgame eval
+ return apply_weight(bonus, Weights[PassedPawns]);
}
+ // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides
+ template<bool HasPopCnt>
+ Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
- // evaluate_trapped_bishop_a7h7() determines whether a bishop on a7/h7
- // (a2/h2 for black) is trapped by enemy pawns, and assigns a penalty
- // if it is.
+ const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
- void evaluate_trapped_bishop_a7h7(const Position &pos, Square s, Color us,
- EvalInfo &ei) {
+ // Step 1. Hunt for unstoppable pawns. If we find at least one, record how many plies
+ // are required for promotion
+ int pliesToGo[2] = {256, 256};
- assert(square_is_ok(s));
- assert(pos.piece_on(s) == bishop_of_color(us));
+ for (Color c = WHITE; c <= BLACK; c++)
+ {
+ // Skip if other side has non-pawn pieces
+ if (pos.non_pawn_material(opposite_color(c)))
+ continue;
- Square b6 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B6 : SQ_G6);
- Square b8 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B8 : SQ_G8);
+ Bitboard b = ei.pi->passed_pawns(c);
- if ( pos.piece_on(b6) == pawn_of_color(opposite_color(us))
- && pos.see(s, b6) < 0
- && pos.see(s, b8) < 0)
- {
- ei.mgValue -= Sign[us] * TrappedBishopA7H7Penalty;
- ei.egValue -= Sign[us] * TrappedBishopA7H7Penalty;
- }
- }
+ while (b)
+ {
+ Square s = pop_1st_bit(&b);
+ Square queeningSquare = relative_square(c, make_square(square_file(s), RANK_8));
+ int mtg = RANK_8 - relative_rank(c, s) - int(relative_rank(c, s) == RANK_2);
+ int oppmtg = square_distance(pos.king_square(opposite_color(c)), queeningSquare) - int(c != pos.side_to_move());
+ bool pathDefended = ((ei.attackedBy[c][0] & squares_in_front_of(c, s)) == squares_in_front_of(c, s));
- // evaluate_trapped_bishop_a1h1() determines whether a bishop on a1/h1
- // (a8/h8 for black) is trapped by a friendly pawn on b2/g2 (b7/g7 for
- // black), and assigns a penalty if it is. This pattern can obviously
- // only occur in Chess960 games.
+ if (mtg >= oppmtg && !pathDefended)
+ continue;
- void evaluate_trapped_bishop_a1h1(const Position &pos, Square s, Color us,
- EvalInfo &ei) {
- Piece pawn = pawn_of_color(us);
- Square b2, b3, c3;
+ int blockerCount = count_1s<Max15>(squares_in_front_of(c, s) & pos.occupied_squares());
+ mtg += blockerCount;
- assert(Chess960);
- assert(square_is_ok(s));
- assert(pos.piece_on(s) == bishop_of_color(us));
+ if (mtg >= oppmtg && !pathDefended)
+ continue;
- if(square_file(s) == FILE_A) {
- b2 = relative_square(us, SQ_B2);
- b3 = relative_square(us, SQ_B3);
- c3 = relative_square(us, SQ_C3);
- }
- else {
- b2 = relative_square(us, SQ_G2);
- b3 = relative_square(us, SQ_G3);
- c3 = relative_square(us, SQ_F3);
+ int ptg = 2 * mtg - int(c == pos.side_to_move());
+
+ if (ptg < pliesToGo[c])
+ pliesToGo[c] = ptg;
+ }
}
- if(pos.piece_on(b2) == pawn) {
- Value penalty;
+ // 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(pliesToGo[WHITE] - pliesToGo[BLACK]) < 3)
+ return make_score(0, 0);
- if(!pos.square_is_empty(b3))
- penalty = 2*TrappedBishopA1H1Penalty;
- else if(pos.piece_on(c3) == pawn)
- penalty = TrappedBishopA1H1Penalty;
- else
- penalty = TrappedBishopA1H1Penalty / 2;
+ Color winnerSide = (pliesToGo[WHITE] < pliesToGo[BLACK] ? WHITE : BLACK);
+ Color loserSide = opposite_color(winnerSide);
+
+ // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
+ // We collect the potential candidates in potentialBB.
+ Bitboard pawnBB = pos.pieces(PAWN, loserSide);
+ Bitboard potentialBB = pawnBB;
+ const Bitboard passedBB = ei.pi->passed_pawns(loserSide);
- ei.mgValue -= Sign[us] * penalty;
- ei.egValue -= Sign[us] * penalty;
+ while(pawnBB)
+ {
+ Square psq = pop_1st_bit(&pawnBB);
+
+ // Check direct advancement
+ int mtg = RANK_8 - relative_rank(loserSide, psq) - int(relative_rank(loserSide, psq) == RANK_2);
+ int ptg = 2 * mtg - int(loserSide == pos.side_to_move());
+
+ // Check if (without even considering any obstacles) we're too far away
+ if (pliesToGo[winnerSide] + 3 <= ptg)
+ {
+ clear_bit(&potentialBB, psq);
+ continue;
+ }
+
+ // If this is passed pawn, then it _may_ promote in time. We give up.
+ if (bit_is_set(passedBB, psq))
+ return make_score(0, 0);
+
+ // Doubled pawn is worthless
+ if (squares_in_front_of(loserSide, psq) & (pos.pieces(PAWN, loserSide)))
+ {
+ clear_bit(&potentialBB, psq);
+ continue;
+ }
}
- }
+ // Step 4. Check new passed pawn creation through king capturing and sacrifises
+ pawnBB = potentialBB;
+ while(pawnBB)
+ {
+ Square psq = pop_1st_bit(&pawnBB);
- // apply_weight applies an evaluation weight to a value.
+ int mtg = RANK_8 - relative_rank(loserSide, psq) - int(relative_rank(loserSide, psq) == RANK_2);
+ int ptg = 2 * mtg - int(loserSide == pos.side_to_move());
- inline Value apply_weight(Value v, int w) {
- return (v*w) / 0x100;
- }
+ // Generate list of obstacles
+ Bitboard obsBB = passed_pawn_mask(loserSide, psq) & pos.pieces(PAWN, winnerSide);
+ const bool pawnIsOpposed = squares_in_front_of(loserSide, psq) & obsBB;
+ assert(obsBB);
+ // How many plies does it take to remove all the obstacles?
+ int sacptg = 0;
+ int realObsCount = 0;
+ int minKingDist = 256;
- // 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.
+ while(obsBB)
+ {
+ Square obSq = pop_1st_bit(&obsBB);
+ int minMoves = 256;
- Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]) {
+ // Check pawns that can give support to overcome obstacle (Eg. wp: a4,b4 bp: b2. b4 is giving support)
+ if (!pawnIsOpposed && square_file(psq) != square_file(obSq))
+ {
+ Bitboard supBB = in_front_bb(winnerSide, Square(obSq + (winnerSide == WHITE ? 8 : -8)))
+ & neighboring_files_bb(psq) & potentialBB;
- assert(mv > -VALUE_INFINITE && mv < VALUE_INFINITE);
- assert(ev > -VALUE_INFINITE && ev < VALUE_INFINITE);
- assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
+ while(supBB) // This while-loop could be replaced with supSq = LSB/MSB(supBB) (depending on color)
+ {
+ Square supSq = pop_1st_bit(&supBB);
+ int dist = square_distance(obSq, supSq);
+ minMoves = Min(minMoves, dist - 2);
+ }
+
+ }
+
+ // Check pawns that can be sacrifised
+ Bitboard sacBB = passed_pawn_mask(winnerSide, obSq) & neighboring_files_bb(obSq) & potentialBB & ~(1ULL << psq);
+
+ while(sacBB) // This while-loop could be replaced with sacSq = LSB/MSB(sacBB) (depending on color)
+ {
+ Square sacSq = pop_1st_bit(&sacBB);
+ int dist = square_distance(obSq, sacSq);
+ minMoves = Min(minMoves, dist - 2);
+ }
+
+ // If obstacle can be destroyed with immediate pawn sacrifise, it's not real obstacle
+ if (minMoves <= 0)
+ continue;
+
+ // Pawn sac calculations
+ sacptg += minMoves * 2;
+
+ // King capture calc
+ realObsCount++;
+ int kingDist = square_distance(pos.king_square(loserSide), obSq);
+ minKingDist = Min(minKingDist, kingDist);
+ }
+
+ // Check if pawn sac plan _may_ save the day
+ if (pliesToGo[winnerSide] + 3 > ptg + sacptg)
+ return make_score(0, 0);
+
+ // Check if king capture plan _may_ save the day (contains some false positives)
+ int kingptg = (minKingDist + realObsCount) * 2;
+ if (pliesToGo[winnerSide] + 3 > ptg + kingptg)
+ return make_score(0, 0);
+ }
+
+ // Step 5. Assign bonus
+ const int Sign[2] = {1, -1};
+ return Sign[winnerSide] * make_score(0, (Value) 0x500 - 0x20 * pliesToGo[winnerSide]);
+ }
- ev = apply_scale_factor(ev, sf[(ev > Value(0) ? WHITE : BLACK)]);
- Value result = Value(int((mv * ph + ev * (128 - ph)) / 128));
- return Value(int(result) & ~(GrainSize - 1));
+ // 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.
+ template<Color Us, bool HasPopCnt>
+ int evaluate_space(const Position& pos, EvalInfo& ei) {
+
+ const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+
+ // Find the safe squares for our pieces inside the area defined by
+ // 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)
+ & ~ei.attackedBy[Them][PAWN]
+ & (ei.attackedBy[Us][0] | ~ei.attackedBy[Them][0]);
+
+ // Find all squares which are at most three squares behind some friendly pawn
+ Bitboard behind = pos.pieces(PAWN, Us);
+ behind |= (Us == WHITE ? behind >> 8 : behind << 8);
+ behind |= (Us == WHITE ? behind >> 16 : behind << 16);
+
+ return count_1s<Max15>(safe) + count_1s<Max15>(behind & safe);
}
- // count_1s_8bit() counts the number of nonzero bits in the 8 least
- // significant bits of a Bitboard. This function is used by the king
- // shield evaluation.
+ // apply_weight() applies an evaluation weight to a value trying to prevent overflow
- int count_1s_8bit(Bitboard b) {
- return int(BitCount8Bit[b & 0xFF]);
+ 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);
}
- // compute_weight() computes the value of an evaluation weight, by combining
- // an UCI-configurable weight with an internal weight.
+ // 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, 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);
+ Value ev = Value((eg * int(sf)) / SCALE_FACTOR_NORMAL);
- int compute_weight(int uciWeight, int internalWeight) {
- uciWeight = (uciWeight * 0x100) / 100;
- return (uciWeight * internalWeight) / 0x100;
+ int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128;
+ return Value(result & ~(GrainSize - 1));
}
- // helper used in read_weights()
- int weight_option(const std::string& opt, int weight) {
+ // weight_option() computes the value of an evaluation weight, by combining
+ // two UCI-configurable weights (midgame and endgame) with an internal weight.
- return compute_weight(get_option_value_int(opt), weight);
+ Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
+
+ // Scale option value from 100 to 256
+ int mg = Options[mgOpt].value<int>() * 256 / 100;
+ int eg = Options[egOpt].value<int>() * 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().
+ // parameters. It is called from read_weights().
void init_safety() {
- QueenContactCheckBonus = get_option_value_int("Queen Contact Check Bonus");
- RookContactCheckBonus = get_option_value_int("Rook Contact Check Bonus");
- QueenCheckBonus = get_option_value_int("Queen Check Bonus");
- RookCheckBonus = get_option_value_int("Rook Check Bonus");
- BishopCheckBonus = get_option_value_int("Bishop Check Bonus");
- KnightCheckBonus = get_option_value_int("Knight Check Bonus");
- DiscoveredCheckBonus = get_option_value_int("Discovered Check Bonus");
- MateThreatBonus = get_option_value_int("Mate Threat Bonus");
-
- int maxSlope = get_option_value_int("King Safety Max Slope");
- int peak = get_option_value_int("King Safety Max Value") * 256 / 100;
- double a = get_option_value_int("King Safety Coefficient") / 100.0;
- double b = get_option_value_int("King Safety X Intercept");
- bool quad = (get_option_value_string("King Safety Curve") == "Quadratic");
- bool linear = (get_option_value_string("King Safety Curve") == "Linear");
+ const Value MaxSlope = Value(30);
+ const Value Peak = Value(1280);
+ Value t[100];
+ // First setup the base table
for (int i = 0; i < 100; i++)
{
- if (i < b)
- SafetyTable[i] = Value(0);
- else if(quad)
- SafetyTable[i] = Value((int)(a * (i - b) * (i - b)));
- else if(linear)
- SafetyTable[i] = Value((int)(100 * a * (i - b)));
- }
+ t[i] = Value(int(0.4 * i * i));
- for (int i = 0; i < 100; i++)
- {
- if (SafetyTable[i+1] - SafetyTable[i] > maxSlope)
- for (int j = i + 1; j < 100; j++)
- SafetyTable[j] = SafetyTable[j-1] + Value(maxSlope);
+ if (i > 0)
+ t[i] = Min(t[i], t[i - 1] + MaxSlope);
- if (SafetyTable[i] > Value(peak))
- SafetyTable[i] = Value(peak);
+ 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]);
+ }
}