////
#include <cassert>
-#include <cstring>
+#include <iostream>
+#include <iomanip>
+#include <sstream>
#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 };
+ // 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];
+ };
// Evaluation grain size, must be a power of 2
const int GrainSize = 8;
// Evaluation weights, initialized from UCI options
- Score WeightMobility, WeightPawnStructure;
- Score WeightPassedPawns, WeightSpace;
- Score WeightKingSafety[2];
+ enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem };
+ Score Weights[6];
+
+ typedef 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
// parameters at 100, which looks prettier.
//
// Values modified by Joona Kiiski
- const Score WeightMobilityInternal = make_score(248, 271);
- const Score WeightPawnStructureInternal = make_score(233, 201);
- const Score WeightPassedPawnsInternal = make_score(252, 259);
- const Score WeightSpaceInternal = make_score( 46, 0);
- const Score WeightKingSafetyInternal = make_score(247, 0);
- const Score WeightKingOppSafetyInternal = make_score(259, 0);
-
- // Mobility and outposts bonus modified by Joona Kiiski
-
- typedef Value V;
- #define S(mg, eg) make_score(mg, eg)
-
- CACHE_LINE_ALIGNMENT
-
- // Knight mobility bonus in middle game and endgame, indexed by the number
- // of attacked squares not occupied by friendly piecess.
- const Score KnightMobilityBonus[16] = {
- S(-38,-33), S(-25,-23), S(-12,-13), S( 0,-3),
- S( 12, 7), S( 25, 17), S( 31, 22), S(38, 27), S(38, 27)
- };
-
- // 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 Score BishopMobilityBonus[16] = {
- S(-25,-30), S(-11,-16), S( 3, -2), S(17, 12),
- S( 31, 26), S( 45, 40), 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)
- };
-
- // 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 Score RookMobilityBonus[16] = {
- S(-20,-36), S(-14,-19), S(-8, -3), S(-2, 13),
- S( 4, 29), S( 10, 46), 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)
+ 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 Score QueenMobilityBonus[32] = {
- S(-10,-18), S(-8,-13), S(-6, -7), S(-3, -2), S(-1, 3), S( 1, 8),
- 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)
+ // 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) }
};
- // Pointers table to access mobility tables through piece type
- const Score* MobilityBonus[8] = { 0, 0, KnightMobilityBonus, BishopMobilityBonus,
- RookMobilityBonus, QueenMobilityBonus, 0, 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(4), V(8), V(8), V(4), V(0), V(0), // 3
- V(0), V(4),V(17),V(26),V(26),V(17), V(4), V(0), // 4
- V(0), V(8),V(26),V(35),V(35),V(26), V(8), V(0), // 5
- V(0), V(4),V(17),V(17),V(17),V(17), V(4), 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
- };
-
- const Value BishopOutpostBonus[64] = {
+ // 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), // 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(21),V(21),V(21),V(21),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
+ 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) }
};
- // ThreatBonus[][] contains bonus according to which piece type
- // attacks which one.
- #define Z S(0, 0)
-
- const Score ThreatBonus[8][8] = {
- { Z, Z, Z, Z, Z, Z, Z, Z }, // not used
- { Z, S(18,37), Z, S(37,47), S(55,97), S(55,97), Z, Z }, // KNIGHT attacks
- { Z, S(18,37), S(37,47), Z, S(55,97), S(55,97), Z, Z }, // BISHOP attacks
- { Z, S( 9,27), S(27,47), S(27,47), Z, S(37,47), Z, Z }, // ROOK attacks
- { Z, S(27,37), S(27,37), S(27,37), S(27,37), Z, Z, Z }, // QUEEN attacks
- { Z, Z, Z, Z, Z, Z, Z, Z }, // not used
- { Z, Z, Z, Z, Z, Z, Z, Z }, // not used
- { Z, Z, Z, Z, Z, Z, Z, Z } // not used
+ // 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
};
- // ThreatedByPawnPenalty[] contains a penalty according to which piece
- // type is attacked by an enemy pawn.
- const Score ThreatedByPawnPenalty[8] = {
- Z, Z, S(56, 70), S(56, 70), S(76, 99), S(86, 118), Z, Z
+ // 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)
};
- #undef Z
#undef S
- // Bonus for unstoppable passed pawns
- const Value UnstoppablePawnValue = Value(0x500);
-
// 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);
// 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 Score TrappedBishopA7H7Penalty = make_score(300, 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
// happen in Chess960 games.
const Score TrappedBishopA1H1Penalty = make_score(100, 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))
- };
-
- // The SpaceMask[color] contains the area of the board which is considered
+ // The SpaceMask[Color] contains the area of the board which is considered
// by the space evaluation. In the middle game, each side is given a bonus
// based on how many squares inside this area are safe and available for
// friendly minor pieces.
- const Bitboard SpaceMask[2] = {
- (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)
+ 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 and table indexed on piece type
- const int QueenAttackWeight = 5;
- const int RookAttackWeight = 3;
- const int BishopAttackWeight = 2;
- const int KnightAttackWeight = 2;
-
- const int AttackWeight[] = { 0, 0, KnightAttackWeight, BishopAttackWeight, RookAttackWeight, QueenAttackWeight };
-
- // Bonuses for safe checks
- const int QueenContactCheckBonus = 3;
- const int DiscoveredCheckBonus = 3;
- const int QueenCheckBonus = 2;
- const int RookCheckBonus = 1;
- const int BishopCheckBonus = 1;
+ // 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;
- // Scan for queen contact mates?
- const bool QueenContactMates = true;
-
- // Bonus for having a mate threat
- const int MateThreatBonus = 3;
-
- // InitKingDanger[] contains bonuses based on the position of the defending
- // king.
- const int InitKingDanger[64] = {
+ // 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.
- // Note that they will be initialized at 0 being global variables.
- MaterialInfoTable* MaterialTable[MAX_THREADS];
- PawnInfoTable* PawnTable[MAX_THREADS];
+ // TracedTerms[Color][PieceType || TracedType] contains a breakdown of the
+ // evaluation terms, used when tracing.
+ Score TracedTerms[2][16];
+ std::stringstream TraceStream;
- // Sizes of pawn and material hash tables
- const int PawnTableSize = 16384;
- const int MaterialTableSize = 1024;
+ enum TracedType {
+ PST = 8, IMBALANCE = 9, MOBILITY = 10, THREAT = 11,
+ PASSED = 12, UNSTOPPABLE = 13, SPACE = 14, TOTAL = 15
+ };
// Function prototypes
- template<bool HasPopCnt>
- Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID);
+ template<bool HasPopCnt, bool Trace>
+ Value do_evaluate(const Position& pos, Value& margin);
template<Color Us, bool HasPopCnt>
- void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei);
+ void init_eval_info(const Position& pos, EvalInfo& ei);
- template<Color Us, bool HasPopCnt>
- void evaluate_king(const Position& pos, EvalInfo& ei);
+ template<Color Us, bool HasPopCnt, bool Trace>
+ Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility);
+
+ template<Color Us, bool HasPopCnt, bool Trace>
+ Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]);
template<Color Us>
- void evaluate_threats(const Position& pos, EvalInfo& ei);
+ Score evaluate_threats(const Position& pos, EvalInfo& ei);
template<Color Us, bool HasPopCnt>
- void evaluate_space(const Position& pos, EvalInfo& ei);
+ int evaluate_space(const Position& pos, EvalInfo& ei);
template<Color Us>
- void evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
+ Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
+
+ template<bool HasPopCnt>
+ Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
- void evaluate_unstoppable_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);
inline Score apply_weight(Score v, Score weight);
- Value scale_by_game_phase(const Score& v, Phase ph, const ScaleFactor sf[]);
+ Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf);
Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
void init_safety();
}
-////
-//// 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) {
+Value evaluate(const Position& pos, Value& margin) {
- return CpuHasPOPCNT ? do_evaluate<true>(pos, ei, threadID)
- : do_evaluate<false>(pos, ei, threadID);
+ return CpuHasPOPCNT ? do_evaluate<true, false>(pos, margin)
+ : do_evaluate<false, false>(pos, margin);
}
namespace {
-template<bool HasPopCnt>
-Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID) {
+double to_cp(Value v) { return double(v) / double(PawnValueMidgame); }
- Bitboard b;
- ScaleFactor factor[2];
+void trace_add(int idx, Score term_w, Score term_b = Score(0)) {
+
+ TracedTerms[WHITE][idx] = term_w;
+ TracedTerms[BLACK][idx] = term_b;
+}
+
+template<bool HasPopCnt, bool Trace>
+Value do_evaluate(const Position& pos, Value& margin) {
+
+ EvalInfo ei;
+ Value margins[2];
+ Score mobilityWhite, mobilityBlack;
assert(pos.is_ok());
- assert(threadID >= 0 && threadID < MAX_THREADS);
- assert(!pos.is_check());
+ assert(pos.thread() >= 0 && pos.thread() < MAX_THREADS);
+ assert(!pos.in_check());
- memset(&ei, 0, sizeof(EvalInfo));
+ // Initialize value by reading the incrementally updated scores included
+ // in the position object (material + piece square tables).
+ Score bonus = pos.value();
- // Initialize by reading the incrementally updated scores included in the
- // position object (material + piece square tables)
- ei.value = pos.value();
+ // margins[] store the uncertainty estimation of position's evaluation
+ // that typically is used by the search for pruning decisions.
+ margins[WHITE] = margins[BLACK] = VALUE_ZERO;
// Probe the material hash table
- ei.mi = MaterialTable[threadID]->get_material_info(pos);
- ei.value += ei.mi->material_value();
+ MaterialInfo* mi = Threads[pos.thread()].materialTable.get_material_info(pos);
+ bonus += 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);
-
- // After get_material_info() call that modifies them
- factor[WHITE] = ei.mi->scale_factor(pos, WHITE);
- factor[BLACK] = ei.mi->scale_factor(pos, BLACK);
+ // configuration, call it and return.
+ if (mi->specialized_eval_exists())
+ {
+ margin = VALUE_ZERO;
+ return mi->evaluate(pos);
+ }
// Probe the pawn hash table
- ei.pi = PawnTable[threadID]->get_pawn_info(pos);
- ei.value += apply_weight(ei.pi->pawns_value(), WeightPawnStructure);
-
- // Initialize king attack bitboards and king attack zones for both sides
- ei.attackedBy[WHITE][KING] = pos.attacks_from<KING>(pos.king_square(WHITE));
- ei.attackedBy[BLACK][KING] = pos.attacks_from<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] = ei.pi->pawn_attacks(WHITE);
- b = ei.attackedBy[WHITE][PAWN] & ei.attackedBy[BLACK][KING];
- if (b)
- ei.kingAttackersCount[WHITE] = count_1s_max_15<HasPopCnt>(b)/2;
-
- ei.attackedBy[BLACK][PAWN] = ei.pi->pawn_attacks(BLACK);
- b = ei.attackedBy[BLACK][PAWN] & ei.attackedBy[WHITE][KING];
- if (b)
- ei.kingAttackersCount[BLACK] = count_1s_max_15<HasPopCnt>(b)/2;
-
- // Evaluate pieces
- evaluate_pieces_of_color<WHITE, HasPopCnt>(pos, ei);
- evaluate_pieces_of_color<BLACK, HasPopCnt>(pos, ei);
-
- // 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.
- evaluate_king<WHITE, HasPopCnt>(pos, ei);
- evaluate_king<BLACK, HasPopCnt>(pos, ei);
-
- // Evaluate tactical threats, we need full attack info including king
- evaluate_threats<WHITE>(pos, ei);
- evaluate_threats<BLACK>(pos, ei);
-
- // Evaluate passed pawns, we need full attack info including king
- evaluate_passed_pawns<WHITE>(pos, ei);
- evaluate_passed_pawns<BLACK>(pos, ei);
-
- // If one side has only a king, check whether exsists any unstoppable passed pawn
- if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
- evaluate_unstoppable_pawns(pos, ei);
+ ei.pi = Threads[pos.thread()].pawnTable.get_pawn_info(pos);
+ bonus += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
- Phase phase = ei.mi->game_phase();
+ // Initialize attack and king safety bitboards
+ init_eval_info<WHITE, HasPopCnt>(pos, ei);
+ init_eval_info<BLACK, HasPopCnt>(pos, ei);
- // 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)
+ // Evaluate pieces and mobility
+ bonus += evaluate_pieces_of_color<WHITE, HasPopCnt, Trace>(pos, ei, mobilityWhite)
+ - evaluate_pieces_of_color<BLACK, HasPopCnt, Trace>(pos, ei, mobilityBlack);
- ei.value += make_score(ei.pi->queenside_storm_value(WHITE) - ei.pi->kingside_storm_value(BLACK), 0);
+ bonus += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
- else if ( square_file(pos.king_square(WHITE)) <= FILE_D
- && square_file(pos.king_square(BLACK)) >= FILE_E)
+ // Evaluate kings after all other pieces because we need complete attack
+ // information when computing the king safety evaluation.
+ bonus += evaluate_king<WHITE, HasPopCnt, Trace>(pos, ei, margins)
+ - evaluate_king<BLACK, HasPopCnt, Trace>(pos, ei, margins);
- ei.value += make_score(ei.pi->kingside_storm_value(WHITE) - ei.pi->queenside_storm_value(BLACK), 0);
+ // Evaluate tactical threats, we need full attack information including king
+ bonus += evaluate_threats<WHITE>(pos, ei)
+ - evaluate_threats<BLACK>(pos, ei);
- // Evaluate space for both sides
- if (ei.mi->space_weight() > 0)
- {
- evaluate_space<WHITE, HasPopCnt>(pos, ei);
- evaluate_space<BLACK, HasPopCnt>(pos, ei);
- }
+ // Evaluate passed pawns, we need full attack information including king
+ bonus += evaluate_passed_pawns<WHITE>(pos, ei)
+ - evaluate_passed_pawns<BLACK>(pos, ei);
+
+ // 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);
+
+ // Evaluate space for both sides, only in middle-game.
+ if (mi->space_weight())
+ {
+ int s_w = evaluate_space<WHITE, HasPopCnt>(pos, ei);
+ int s_b = evaluate_space<BLACK, HasPopCnt>(pos, ei);
+ bonus += apply_weight(make_score((s_w - s_b) * mi->space_weight(), 0), Weights[Space]);
+
+ if (Trace)
+ trace_add(SPACE, apply_weight(make_score(s_w * mi->space_weight(), make_score(0, 0)), Weights[Space]),
+ apply_weight(make_score(s_b * mi->space_weight(), make_score(0, 0)), Weights[Space]));
}
- // Mobility
- ei.value += apply_weight(ei.mobility, WeightMobility);
+ // 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 && eg_value(ei.value) > Value(0))
- || (factor[BLACK] == SCALE_FACTOR_NORMAL && eg_value(ei.value) < 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
- Color stm = pos.side_to_move();
+ margin = margins[pos.side_to_move()];
+ Value v = scale_by_game_phase(bonus, phase, sf);
- Value v = Sign[stm] * scale_by_game_phase(ei.value, phase, factor);
+ if (Trace)
+ {
+ trace_add(PST, pos.value());
+ trace_add(IMBALANCE, mi->material_value());
+ trace_add(PAWN, apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]));
+ trace_add(MOBILITY, apply_weight(mobilityWhite, Weights[Mobility]), apply_weight(mobilityBlack, Weights[Mobility]));
+ trace_add(THREAT, evaluate_threats<WHITE>(pos, ei), evaluate_threats<BLACK>(pos, ei));
+ trace_add(PASSED, evaluate_passed_pawns<WHITE>(pos, ei), evaluate_passed_pawns<BLACK>(pos, ei));
+ trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns<HasPopCnt>(pos, ei));
+ trace_add(TOTAL, bonus);
+ TraceStream << "\nUncertainty margin: White: " << to_cp(margins[WHITE])
+ << ", Black: " << to_cp(margins[BLACK])
+ << "\nScaling: " << std::noshowpos
+ << std::setw(6) << 100.0 * phase/128.0 << "% MG, "
+ << std::setw(6) << 100.0 * (1.0 - phase/128.0) << "% * "
+ << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
+ << "Total evaluation: " << to_cp(v);
+ }
- return (ei.mateThreat[stm] == MOVE_NONE ? v : 8 * QueenValueMidgame - v);
+ return pos.side_to_move() == WHITE ? v : -v;
}
} // namespace
-/// init_eval() initializes various tables used by the evaluation function
-void init_eval(int threads) {
+/// read_weights() reads evaluation weights from the corresponding UCI parameters
- assert(threads <= MAX_THREADS);
+void read_evaluation_uci_options(Color us) {
- 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);
- }
-}
+ // King safety is asymmetrical. Our king danger level is weighted by
+ // "Cowardice" UCI parameter, instead the opponent one by "Aggressiveness".
+ const int kingDangerUs = (us == WHITE ? KingDangerUs : KingDangerThem);
+ const int kingDangerThem = (us == WHITE ? KingDangerThem : KingDangerUs);
+ Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
+ Weights[PawnStructure] = weight_option("Pawn Structure (Middle Game)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
+ Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
+ Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
+ Weights[kingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
+ Weights[kingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
-/// quit_eval() releases heap-allocated memory at program termination
-
-void quit_eval() {
+ // 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;
- for (int i = 0; i < MAX_THREADS; i++)
- {
- delete PawnTable[i];
- delete MaterialTable[i];
- PawnTable[i] = NULL;
- MaterialTable[i] = NULL;
- }
+ init_safety();
}
-/// read_weights() reads evaluation weights from the corresponding UCI parameters
+namespace {
-void read_weights(Color us) {
+ // init_eval_info() initializes king bitboards for given color adding
+ // pawn attacks. To be done at the beginning of the evaluation.
- Color them = opposite_color(us);
+ template<Color Us, bool HasPopCnt>
+ void init_eval_info(const Position& pos, EvalInfo& ei) {
- WeightMobility = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightMobilityInternal);
- WeightPawnStructure = weight_option("Pawn Structure (Middle Game)", "Pawn Structure (Endgame)", WeightPawnStructureInternal);
- WeightPassedPawns = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightPassedPawnsInternal);
- WeightSpace = weight_option("Space", "Space", WeightSpaceInternal);
- WeightKingSafety[us] = weight_option("Cowardice", "Cowardice", WeightKingSafetyInternal);
- WeightKingSafety[them] = weight_option("Aggressiveness", "Aggressiveness", WeightKingOppSafetyInternal);
+ const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
- // If running in analysis mode, make sure we use symmetrical king safety. We do this
- // by replacing both WeightKingSafety[us] and WeightKingSafety[them] by their average.
- if (get_option_value_bool("UCI_AnalyseMode"))
- {
- WeightKingSafety[us] = (WeightKingSafety[us] + WeightKingSafety[them]) / 2;
- WeightKingSafety[them] = WeightKingSafety[us];
- }
- init_safety();
-}
+ Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
+ ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
+ // Init king safety tables only if we are going to use them
+ if ( pos.piece_count(Us, QUEEN)
+ && pos.non_pawn_material(Us) >= QueenValueMidgame + RookValueMidgame)
+ {
+ 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;
+ }
-namespace {
// evaluate_outposts() evaluates bishop and knight outposts squares
template<PieceType Piece, Color Us>
- void evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
+ Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
+ assert (Piece == BISHOP || Piece == KNIGHT);
+
// Initial bonus based on square
- Value bonus = (Piece == BISHOP ? BishopOutpostBonus[relative_square(Us, s)]
- : KnightOutpostBonus[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
+ // no minor piece which can exchange the outpost piece.
if (bonus && bit_is_set(ei.attackedBy[Us][PAWN], s))
{
if ( pos.pieces(KNIGHT, Them) == EmptyBoardBB
else
bonus += bonus / 2;
}
- ei.value += Sign[Us] * make_score(bonus, bonus);
+ return make_score(bonus, bonus);
}
// evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
- template<PieceType Piece, Color Us, bool HasPopCnt>
- void evaluate_pieces(const Position& pos, EvalInfo& ei, Bitboard no_mob_area) {
+ template<PieceType Piece, Color Us, bool HasPopCnt, bool Trace>
+ Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
Bitboard b;
Square s, ksq;
int mob;
File f;
+ Score bonus = SCORE_ZERO;
+ 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;
+
while ((s = *ptr++) != SQ_NONE)
{
// Find attacked squares, including x-ray attacks for bishops and rooks
if (b & ei.kingZone[Us])
{
ei.kingAttackersCount[Us]++;
- ei.kingAttackersWeight[Us] += AttackWeight[Piece];
+ ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
Bitboard bb = (b & ei.attackedBy[Them][KING]);
if (bb)
- ei.kingAdjacentZoneAttacksCount[Us] += count_1s_max_15<HasPopCnt>(bb);
+ ei.kingAdjacentZoneAttacksCount[Us] += count_1s<Max15>(bb);
}
// Mobility
- mob = (Piece != QUEEN ? count_1s_max_15<HasPopCnt>(b & no_mob_area)
- : count_1s<HasPopCnt>(b & no_mob_area));
+ mob = (Piece != QUEEN ? count_1s<Max15>(b & mobilityArea)
+ : count_1s<Full >(b & mobilityArea));
- ei.mobility += Sign[Us] * MobilityBonus[Piece][mob];
+ mobility += MobilityBonus[Piece][mob];
// 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))
- ei.value -= Sign[Us] * ThreatedByPawnPenalty[Piece];
+ bonus -= ThreatedByPawnPenalty[Piece];
// Bishop and knight outposts squares
- if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Them))
- evaluate_outposts<Piece, Us>(pos, ei, s);
-
- // Special patterns: trapped bishops on a7/h7/a2/h2
- // and trapped bishops on a1/h1/a8/h8 in Chess960.
- if (Piece == BISHOP)
- {
- if (bit_is_set(MaskA7H7[Us], s))
- evaluate_trapped_bishop_a7h7(pos, s, Us, ei);
-
- if (Chess960 && bit_is_set(MaskA1H1[Us], s))
- evaluate_trapped_bishop_a1h1(pos, s, Us, ei);
- }
+ if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Us))
+ bonus += evaluate_outposts<Piece, Us>(pos, ei, s);
// Queen or rook on 7th rank
if ( (Piece == ROOK || Piece == QUEEN)
&& relative_rank(Us, s) == RANK_7
&& relative_rank(Us, pos.king_square(Them)) == RANK_8)
{
- ei.value += Sign[Us] * (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
+ bonus += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
+ }
+
+ // Special extra evaluation for bishops
+ if (Piece == BISHOP && pos.is_chess960())
+ {
+ // An important Chess960 pattern: A cornered bishop blocked by
+ // a friendly pawn diagonally in front of it is a very serious
+ // problem, especially when that pawn is also blocked.
+ if (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1))
+ {
+ Square d = pawn_push(Us) + (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;
+ }
+ }
}
// Special extra evaluation for rooks
if (ei.pi->file_is_half_open(Us, f))
{
if (ei.pi->file_is_half_open(Them, f))
- ei.value += Sign[Us] * RookOpenFileBonus;
+ bonus += RookOpenFileBonus;
else
- ei.value += Sign[Us] * RookHalfOpenFileBonus;
+ bonus += RookHalfOpenFileBonus;
}
// Penalize rooks which are trapped inside a king. Penalize more if
{
// 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.value -= Sign[Us] * make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
- : (TrappedRookPenalty - mob * 16), 0);
+ 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)
{
// 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.value -= Sign[Us] * make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
- : (TrappedRookPenalty - mob * 16), 0);
+ bonus -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
+ : (TrappedRookPenalty - mob * 16), 0);
}
}
}
+
+ if (Trace)
+ TracedTerms[Us][Piece] = bonus;
+
+ return bonus;
}
// and the type of attacked one.
template<Color Us>
- void evaluate_threats(const Position& pos, EvalInfo& ei) {
+ Score evaluate_threats(const Position& pos, EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
Bitboard b;
- Score bonus = make_score(0, 0);
+ Score bonus = SCORE_ZERO;
// 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;
+ return SCORE_ZERO;
- // Add bonus according to type of attacked enemy pieces and to the
+ // Add bonus according to type of attacked enemy piece and to the
// type of attacking piece, from knights to queens. Kings are not
- // considered because are already special handled in king evaluation.
+ // considered because are already handled in king evaluation.
for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
{
b = ei.attackedBy[Us][pt1] & weakEnemies;
if (b & pos.pieces(pt2))
bonus += ThreatBonus[pt1][pt2];
}
- ei.value += Sign[Us] * bonus;
+ return bonus;
}
// evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
// pieces of a given color.
- template<Color Us, bool HasPopCnt>
- void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei) {
+ template<Color Us, bool HasPopCnt, bool Trace>
+ 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 no_mob_area = ~(ei.attackedBy[Them][PAWN] | pos.pieces_of_color(Us));
+ const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces_of_color(Us));
- evaluate_pieces<KNIGHT, Us, HasPopCnt>(pos, ei, no_mob_area);
- evaluate_pieces<BISHOP, Us, HasPopCnt>(pos, ei, no_mob_area);
- evaluate_pieces<ROOK, Us, HasPopCnt>(pos, ei, no_mob_area);
- evaluate_pieces<QUEEN, Us, HasPopCnt>(pos, ei, no_mob_area);
+ bonus += evaluate_pieces<KNIGHT, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
+ bonus += evaluate_pieces<BISHOP, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
+ bonus += evaluate_pieces<ROOK, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
+ bonus += evaluate_pieces<QUEEN, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
// Sum up all attacked squares
ei.attackedBy[Us][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
| ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
| ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
+ return bonus;
}
// evaluate_king<>() assigns bonuses and penalties to a king of a given color
- template<Color Us, bool HasPopCnt>
- void evaluate_king(const Position& pos, EvalInfo& ei) {
+ template<Color Us, bool HasPopCnt, bool Trace>
+ Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
+ const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
const Color Them = (Us == WHITE ? BLACK : WHITE);
- Bitboard undefended, attackedByOthers, escapeSquares, occ, b, b2, safe;
- Square from, to;
- bool sente;
- int attackUnits, count, shelter = 0;
- const Square s = pos.king_square(Us);
+ Bitboard undefended, b, b1, b2, safe;
+ int attackUnits;
+ const Square ksq = pos.king_square(Us);
// King shelter
- if (relative_rank(Us, s) <= RANK_4)
- {
- shelter = ei.pi->get_king_shelter(pos, Us, s);
- ei.value += Sign[Us] * make_score(shelter, 0);
- }
+ Score bonus = ei.pi->king_shelter<Us>(pos, ksq);
// King safety. This is quite complicated, and is almost certainly far
// from optimally tuned.
- if ( pos.piece_count(Them, QUEEN) >= 1
- && ei.kingAttackersCount[Them] >= 2
- && pos.non_pawn_material(Them) >= QueenValueMidgame + RookValueMidgame
+ if ( ei.kingAttackersCount[Them] >= 2
&& ei.kingAdjacentZoneAttacksCount[Them])
{
- // Is it the attackers turn to move?
- sente = (Them == pos.side_to_move());
-
- // Find the attacked squares around the king which has no defenders
- // apart from the king itself
- undefended = ei.attacked_by(Them) & ei.attacked_by(Us, KING);
- undefended &= ~( 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));
-
- // Initialize the 'attackUnits' variable, which is used later on as an
- // index to the SafetyTable[] array. The initial value 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.
- attackUnits = Min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
- + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + count_1s_max_15<HasPopCnt>(undefended))
- + InitKingDanger[relative_square(Us, s)]
- - (shelter >> 5);
-
- // Analyse safe queen contact checks
- b = undefended & ei.attacked_by(Them, QUEEN) & ~pos.pieces_of_color(Them);
- if (b)
- {
- attackedByOthers = ei.attacked_by(Them, PAWN) | ei.attacked_by(Them, KNIGHT)
- | ei.attacked_by(Them, BISHOP) | ei.attacked_by(Them, ROOK);
-
- b &= attackedByOthers;
-
- // Squares attacked by the queen and supported by another enemy piece and
- // not defended by other pieces but our king.
+ // 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.
- count = count_1s_max_15<HasPopCnt>(b);
- attackUnits += QueenContactCheckBonus * count * (sente ? 2 : 1);
-
- // Is there a mate threat?
- if (QueenContactMates && !pos.is_check())
- {
- escapeSquares = pos.attacks_from<KING>(s) & ~pos.pieces_of_color(Us) & ~attackedByOthers;
- occ = pos.occupied_squares();
- while (b)
- {
- to = pop_1st_bit(&b);
-
- // Do we have escape squares from queen contact check attack ?
- 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 < pos.piece_count(Them, QUEEN); i++)
- {
- from = pos.piece_list(Them, QUEEN, i);
- if ( bit_is_set(pos.attacks_from<QUEEN>(from), to)
- && !bit_is_set(pos.pinned_pieces(Them), from)
- && !(rook_attacks_bb(to, occ & ClearMaskBB[from]) & pos.pieces(ROOK, QUEEN, Us))
- && !(bishop_attacks_bb(to, occ & ClearMaskBB[from]) & pos.pieces(BISHOP, QUEEN, Us)))
-
- // Set the mate threat move
- 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 distance checks
- safe = ~(pos.pieces_of_color(Them) | ei.attacked_by(Us));
+ // 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);
- if (QueenCheckBonus > 0 || RookCheckBonus > 0)
- {
- b = pos.attacks_from<ROOK>(s) & safe;
+ // 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<HasPopCnt>(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);
+ }
- // Rook checks
- b2 = b & ei.attacked_by(Them, ROOK);
- if (b2)
- attackUnits += RookCheckBonus * count_1s_max_15<HasPopCnt>(b2);
- }
- if (QueenCheckBonus > 0 || BishopCheckBonus > 0)
- {
- b = pos.attacks_from<BISHOP>(s) & safe;
+ // Analyse enemy's safe distance checks for sliders and knights
+ safe = ~(pos.pieces_of_color(Them) | ei.attackedBy[Us][0]);
- // Queen checks
- b2 = b & ei.attacked_by(Them, QUEEN);
- if (b2)
- attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b2);
+ b1 = pos.attacks_from<ROOK>(ksq) & safe;
+ b2 = pos.attacks_from<BISHOP>(ksq) & safe;
- // Bishop checks
- b2 = b & ei.attacked_by(Them, BISHOP);
- if (b2)
- attackUnits += BishopCheckBonus * count_1s_max_15<HasPopCnt>(b2);
- }
- if (KnightCheckBonus > 0)
- {
- b = pos.attacks_from<KNIGHT>(s) & safe;
+ // Enemy queen safe checks
+ b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
+ if (b)
+ attackUnits += QueenCheckBonus * count_1s<Max15>(b);
- // Knight checks
- b2 = b & ei.attacked_by(Them, KNIGHT);
- if (b2)
- attackUnits += KnightCheckBonus * count_1s_max_15<HasPopCnt>(b2);
- }
+ // Enemy rooks safe checks
+ b = b1 & ei.attackedBy[Them][ROOK];
+ if (b)
+ attackUnits += RookCheckBonus * count_1s<Max15>(b);
- // Analyse discovered checks (only for non-pawns right now, consider
- // adding pawns later).
- if (DiscoveredCheckBonus)
- {
- b = pos.discovered_check_candidates(Them) & ~pos.pieces(PAWN);
- if (b)
- attackUnits += DiscoveredCheckBonus * count_1s_max_15<HasPopCnt>(b) * (sente ? 2 : 1);
- }
+ // Enemy bishops safe checks
+ b = b2 & ei.attackedBy[Them][BISHOP];
+ if (b)
+ attackUnits += BishopCheckBonus * 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.
- attackUnits = Min(99, Max(0, attackUnits));
-
- // 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.
- Score v = apply_weight(make_score(SafetyTable[attackUnits], 0), WeightKingSafety[Us]);
- ei.value -= Sign[Us] * v;
- ei.futilityMargin[Us] += mg_value(v);
+ // 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]);
}
+
+ if (Trace)
+ TracedTerms[Us][KING] = bonus;
+
+ return bonus;
}
// evaluate_passed_pawns<>() evaluates the passed pawns of the given color
template<Color Us>
- void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
+ Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
- Bitboard b = ei.pi->passed_pawns() & pos.pieces_of_color(Us);
+ 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) == piece_of_color_and_type(Us, PAWN));
assert(pos.pawn_is_passed(Us, s));
int r = int(relative_rank(Us, s) - RANK_2);
- int tr = Max(0, r * (r - 1));
+ int rr = r * (r - 1);
// Base bonus based on rank
- Value mbonus = Value(20 * tr);
- Value ebonus = Value(10 + r * r * 10);
+ Value mbonus = Value(20 * rr);
+ Value ebonus = Value(10 * (rr + r + 1));
- // Adjust bonus based on king proximity
- if (tr)
+ if (rr)
{
Square blockSq = s + pawn_push(Us);
- ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 3 * tr);
- ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * 1 * tr);
- ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 6 * tr);
+ // 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))
{
- // There are no enemy pawns in the pawn's path
- Bitboard b2 = squares_in_front_of(Us, s);
-
- assert((b2 & pos.pieces(PAWN, Them)) == EmptyBoardBB);
-
- // Squares attacked by us
- Bitboard b4 = b2 & ei.attacked_by(Us);
-
- // Squares attacked or occupied by enemy pieces
- Bitboard b3 = b2 & (ei.attacked_by(Them) | pos.pieces_of_color(Them));
+ 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.
- if ( (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them))
- && (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from<QUEEN>(s)))
- b3 = b2;
-
- // Are any of the squares in the pawn's path attacked or occupied by the enemy?
- if (b3 == EmptyBoardBB)
- // No enemy attacks or pieces, huge bonus!
- // Even bigger if we protect the pawn's path
- ebonus += Value(tr * (b2 == b4 ? 17 : 15));
+ // 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(tr * ((b3 & b4) == b3 ? 13 : 8));
+ 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 ((b2 & pos.pieces_of_color(Us)) == EmptyBoardBB)
- ebonus += Value(tr);
+ if (!(squaresToQueen & pos.pieces_of_color(Us)))
+ ebonus += Value(rr);
}
- } // tr != 0
+ } // rr != 0
- // If the pawn is supported by a friendly pawn, increase bonus
- Bitboard b1 = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
- if (b1 & rank_bb(s))
+ // 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 (pos.attacks_from<PAWN>(s, Them) & b1)
+ else if (supportingPawns & rank_bb(s - pawn_push(Us)))
ebonus += Value(r * 12);
// Rook pawns are a special case: They are sometimes worse, and
// 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)
+ 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.value += Sign[Us] * apply_weight(make_score(mbonus, ebonus), WeightPassedPawns);
+ } while (b);
- } // while
+ // 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
- void evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
+ template<bool HasPopCnt>
+ Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
- int movesToGo[2] = {0, 0};
- Square pawnToGo[2] = {SQ_NONE, SQ_NONE};
+ const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
- for (Color c = WHITE; c <= BLACK; c++)
+ Bitboard b1, b2, queeningPath, candidates, supBB, sacBB;
+ Square s1, s2, queeningSquare, supSq, sacSq;
+ Color c, winnerSide, loserSide;
+ bool pathDefended, opposed;
+ int pliesToGo, movesToGo, oppMovesToGo;
+ int pliesToQueen[] = { 256, 256 };
+
+ // Step 1. Hunt for unstoppable pawns. If we find at least one, record how many plies
+ // are required for promotion
+ for (c = WHITE; c <= BLACK; c++)
{
- // Skip evaluation if other side has non-pawn pieces
+ // Skip if other side has non-pawn pieces
if (pos.non_pawn_material(opposite_color(c)))
continue;
- Bitboard b = ei.pi->passed_pawns() & pos.pieces_of_color(c);
+ b1 = ei.pi->passed_pawns(c);
- while (b)
+ while (b1)
{
- Square s = pop_1st_bit(&b);
- Square queeningSquare = relative_square(c, make_square(square_file(s), RANK_8));
- int d = square_distance(s, queeningSquare)
- - square_distance(pos.king_square(opposite_color(c)), queeningSquare)
- + int(c != pos.side_to_move());
+ s1 = pop_1st_bit(&b1);
+ queeningSquare = relative_square(c, make_square(square_file(s1), RANK_8));
+ queeningPath = squares_in_front_of(c, s1);
- if (d < 0)
- {
- int mtg = RANK_8 - relative_rank(c, s);
- int blockerCount = count_1s_max_15(squares_in_front_of(c, s) & pos.occupied_squares());
- mtg += blockerCount;
- d += blockerCount;
- if (d < 0 && (!movesToGo[c] || movesToGo[c] > mtg))
- {
- movesToGo[c] = mtg;
- pawnToGo[c] = s;
- }
- }
- }
- }
+ // Compute plies from queening and check direct advancement
+ movesToGo = rank_distance(s1, queeningSquare) - int(relative_rank(c, s1) == RANK_2);
+ oppMovesToGo = square_distance(pos.king_square(opposite_color(c)), queeningSquare) - int(c != pos.side_to_move());
+ pathDefended = ((ei.attackedBy[c][0] & queeningPath) == queeningPath);
- // Neither side has an unstoppable passed pawn?
- if (!(movesToGo[WHITE] | movesToGo[BLACK]))
- return;
+ if (movesToGo >= oppMovesToGo && !pathDefended)
+ continue;
- // Does only one side have an unstoppable passed pawn?
- if (!movesToGo[WHITE] || !movesToGo[BLACK])
- {
- Color winnerSide = movesToGo[WHITE] ? WHITE : BLACK;
- ei.value += make_score(0, Sign[winnerSide] * (UnstoppablePawnValue - Value(0x40 * movesToGo[winnerSide])));
- }
- else
- { // 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()]--;
-
- Color winnerSide = movesToGo[WHITE] < movesToGo[BLACK] ? WHITE : BLACK;
- Color loserSide = opposite_color(winnerSide);
-
- // If one side queens at least three plies before the other, that side wins
- if (movesToGo[winnerSide] <= movesToGo[loserSide] - 3)
- ei.value += Sign[winnerSide] * make_score(0, UnstoppablePawnValue - Value(0x40 * (movesToGo[winnerSide]/2)));
-
- // If one side queens one ply before the other and checks the king or attacks
- // the undefended opponent's queening square, that side wins. To avoid cases
- // where the opponent's king could move somewhere before first pawn queens we
- // consider only free paths to queen for both pawns.
- else if ( !(squares_in_front_of(WHITE, pawnToGo[WHITE]) & pos.occupied_squares())
- && !(squares_in_front_of(BLACK, pawnToGo[BLACK]) & pos.occupied_squares()))
- {
- assert(movesToGo[loserSide] - movesToGo[winnerSide] == 1);
+ // Opponent king cannot block because path is defended and position
+ // is not in check. So only friendly pieces can be blockers.
+ assert(!pos.in_check());
+ assert(queeningPath & pos.occupied_squares() == queeningPath & pos.pieces_of_color(c));
+
+ // Add moves needed to free the path from friendly pieces and retest condition
+ movesToGo += count_1s<Max15>(queeningPath & pos.pieces_of_color(c));
- Square winnerQSq = relative_square(winnerSide, make_square(square_file(pawnToGo[winnerSide]), RANK_8));
- Square loserQSq = relative_square(loserSide, make_square(square_file(pawnToGo[loserSide]), RANK_8));
+ if (movesToGo >= oppMovesToGo && !pathDefended)
+ continue;
- Bitboard b = pos.occupied_squares();
- clear_bit(&b, pawnToGo[winnerSide]);
- clear_bit(&b, pawnToGo[loserSide]);
- b = queen_attacks_bb(winnerQSq, b);
+ pliesToGo = 2 * movesToGo - int(c == pos.side_to_move());
- if ( (b & pos.pieces(KING, loserSide))
- ||(bit_is_set(b, loserQSq) && !bit_is_set(ei.attacked_by(loserSide), loserQSq)))
- ei.value += Sign[winnerSide] * make_score(0, UnstoppablePawnValue - Value(0x40 * (movesToGo[winnerSide]/2)));
+ if (pliesToGo < pliesToQueen[c])
+ pliesToQueen[c] = pliesToGo;
}
}
- }
+ // Step 2. If either side cannot promote at least three plies before the other side then situation
+ // becomes too complex and we give up. Otherwise we determine the possibly "winning side"
+ if (abs(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3)
+ return SCORE_ZERO;
- // 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.
+ winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK);
+ loserSide = opposite_color(winnerSide);
- void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo &ei) {
+ // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
+ // We collect the potential candidates in potentialBB.
+ b1 = candidates = pos.pieces(PAWN, loserSide);
- assert(square_is_ok(s));
- assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
+ while (b1)
+ {
+ s1 = pop_1st_bit(&b1);
- 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);
+ // Compute plies from queening
+ queeningSquare = relative_square(loserSide, make_square(square_file(s1), RANK_8));
+ movesToGo = rank_distance(s1, queeningSquare) - int(relative_rank(loserSide, s1) == RANK_2);
+ pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
- if ( pos.piece_on(b6) == piece_of_color_and_type(opposite_color(us), PAWN)
- && pos.see(s, b6) < 0
- && pos.see(s, b8) < 0)
- {
- ei.value -= Sign[us] * TrappedBishopA7H7Penalty;
+ // Check if (without even considering any obstacles) we're too far away or doubled
+ if ( pliesToQueen[winnerSide] + 3 <= pliesToGo
+ || (squares_in_front_of(loserSide, s1) & pos.pieces(PAWN, loserSide)))
+ clear_bit(&candidates, s1);
}
- }
+ // If any candidate is already a passed pawn it _may_ promote in time. We give up.
+ if (candidates & ei.pi->passed_pawns(loserSide))
+ return SCORE_ZERO;
- // 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.
+ // Step 4. Check new passed pawn creation through king capturing and sacrifices
+ b1 = candidates;
- void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei) {
+ while (b1)
+ {
+ s1 = pop_1st_bit(&b1);
- Piece pawn = piece_of_color_and_type(us, PAWN);
- Square b2, b3, c3;
+ // Compute plies from queening
+ queeningSquare = relative_square(loserSide, make_square(square_file(s1), RANK_8));
+ movesToGo = rank_distance(s1, queeningSquare) - int(relative_rank(loserSide, s1) == RANK_2);
+ pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
- assert(Chess960);
- assert(square_is_ok(s));
- assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
+ // Generate list of obstacles
+ opposed = squares_in_front_of(loserSide, s1) & pos.pieces(PAWN, winnerSide);
+ b2 = passed_pawn_mask(loserSide, s1) & pos.pieces(PAWN, winnerSide);
- 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);
- }
+ assert(b2);
- if (pos.piece_on(b2) == pawn)
- {
- Score penalty;
+ // How many plies does it take to remove all the obstacles?
+ int sacptg = 0;
+ int realObsCount = 0;
+ int minKingDist = 256;
+ int kingptg = 256;
- if (!pos.square_is_empty(b3))
- penalty = 2 * TrappedBishopA1H1Penalty;
- else if (pos.piece_on(c3) == pawn)
- penalty = TrappedBishopA1H1Penalty;
- else
- penalty = TrappedBishopA1H1Penalty / 2;
+ while (b2)
+ {
+ s2 = pop_1st_bit(&b2);
+ movesToGo = 256;
+
+ // Check pawns that can give support to overcome obstacle, for instance
+ // black pawns: a4, b4 white: b2 then pawn in b4 is giving support.
+ if (!opposed)
+ {
+ supBB = in_front_bb(winnerSide, s2 + pawn_push(winnerSide)) & neighboring_files_bb(s1) & candidates;
+
+ while (supBB) // This while-loop could be replaced with supSq = LSB/MSB(supBB) (depending on color)
+ {
+ supSq = pop_1st_bit(&supBB);
+ movesToGo = Min(movesToGo, square_distance(s2, supSq) - 2);
+ }
+ }
+
+ // Check pawns that can be sacrificed
+ sacBB = passed_pawn_mask(winnerSide, s2) & neighboring_files_bb(s2) & candidates & ~(1ULL << s1);
+
+ while (sacBB) // This while-loop could be replaced with sacSq = LSB/MSB(sacBB) (depending on color)
+ {
+ sacSq = pop_1st_bit(&sacBB);
+ movesToGo = Min(movesToGo, square_distance(s2, sacSq) - 2);
+ }
+
+ // Good, obstacle can be destroyed with an immediate pawn sacrifice,
+ // it's not a real obstacle and we have nothing to add to pliesToGo.
+ if (movesToGo <= 0)
+ continue;
+
+ // Plies needed to sacrifice the pawn
+ sacptg += movesToGo * 2;
+ realObsCount++;
+
+ // Plies needed for the king to capture opposing pawn
+ minKingDist = Min(minKingDist, square_distance(pos.king_square(loserSide), s2));
+ kingptg = (minKingDist + realObsCount) * 2;
+ }
+
+ // Check if pawn sacrifice plan _may_ save the day
+ if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg)
+ return SCORE_ZERO;
- ei.value -= Sign[us] * penalty;
+ // Check if king capture plan _may_ save the day (contains some false positives)
+ if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg)
+ return SCORE_ZERO;
}
+
+ // Winning pawn is unstoppable and will promote as first, return big score
+ Score score = make_score(0, (Value) 0x500 - 0x20 * pliesToQueen[winnerSide]);
+ return winnerSide == WHITE ? score : -score;
}
// available for minor pieces on the central four files on ranks 2--4. Safe
// squares one, two or three squares behind a friendly pawn are counted
// twice. Finally, the space bonus is scaled by a weight taken from the
- // material hash table.
+ // material hash table. The aim is to improve play on game opening.
template<Color Us, bool HasPopCnt>
- void evaluate_space(const Position& pos, EvalInfo& ei) {
+ 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[us]. A square is unsafe if it is attacked by an enemy
+ // SpaceMask[]. A square is unsafe if it is attacked by an enemy
// pawn, or if it is undefended and attacked by an enemy piece.
+ Bitboard safe = SpaceMask[Us]
+ & ~pos.pieces(PAWN, Us)
+ & ~ei.attackedBy[Them][PAWN]
+ & (ei.attackedBy[Us][0] | ~ei.attackedBy[Them][0]);
- Bitboard safeSquares = SpaceMask[Us]
- & ~pos.pieces(PAWN, Us)
- & ~ei.attacked_by(Them, PAWN)
- & ~(~ei.attacked_by(Us) & ei.attacked_by(Them));
-
- // Find all squares which are at most three squares behind some friendly
- // pawn.
- Bitboard behindFriendlyPawns = pos.pieces(PAWN, Us);
- behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 8 : behindFriendlyPawns << 8);
- behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 16 : behindFriendlyPawns << 16);
+ // 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);
- int space = count_1s_max_15<HasPopCnt>(safeSquares)
- + count_1s_max_15<HasPopCnt>(behindFriendlyPawns & safeSquares);
-
- ei.value += Sign[Us] * apply_weight(make_score(space * ei.mi->space_weight(), 0), WeightSpace);
+ return count_1s<Max15>(safe) + count_1s<Max15>(behind & safe);
}
// apply_weight() applies an evaluation weight to a value trying to prevent overflow
inline Score apply_weight(Score v, Score w) {
- return make_score((int(mg_value(v)) * mg_value(w)) / 0x100, (int(eg_value(v)) * eg_value(w)) / 0x100);
+ return make_score((int(mg_value(v)) * mg_value(w)) / 0x100,
+ (int(eg_value(v)) * eg_value(w)) / 0x100);
}
- // scale_by_game_phase() interpolates between a middle game and an endgame
- // score, based on game phase. It also scales the return value by a
- // ScaleFactor array.
+ // scale_by_game_phase() interpolates between a middle game and an endgame score,
+ // based on game phase. It also scales the return value by a ScaleFactor array.
- Value scale_by_game_phase(const Score& v, Phase ph, const ScaleFactor sf[]) {
+ Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf) {
assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
- Value ev = apply_scale_factor(eg_value(v), sf[(eg_value(v) > Value(0) ? WHITE : BLACK)]);
-
- int result = (mg_value(v) * ph + ev * (128 - ph)) / 128;
- return Value(result & ~(GrainSize - 1));
+ int ev = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
+ int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128;
+ return Value((result + GrainSize / 2) & ~(GrainSize - 1));
}
Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
- Score uciWeight = make_score(get_option_value_int(mgOpt), get_option_value_int(egOpt));
+ // Scale option value from 100 to 256
+ int mg = Options[mgOpt].value<int>() * 256 / 100;
+ int eg = Options[egOpt].value<int>() * 256 / 100;
- // Convert to integer to prevent overflow
- int mg = mg_value(uciWeight);
- int eg = eg_value(uciWeight);
-
- mg = (mg * 0x100) / 100;
- eg = (eg * 0x100) / 100;
- mg = (mg * mg_value(internalWeight)) / 0x100;
- eg = (eg * eg_value(internalWeight)) / 0x100;
- return make_score(mg, eg);
+ 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() {
- int maxSlope = 30;
- int peak = 0x500;
- double a = 0.4;
- double b = 0.0;
+ 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
- SafetyTable[i] = Value((int)(a * (i - b) * (i - b)));
+ t[i] = Value(int(0.4 * i * i));
+
+ if (i > 0)
+ t[i] = Min(t[i], t[i - 1] + MaxSlope);
+
+ t[i] = Min(t[i], Peak);
}
- for (int i = 1; i < 100; i++)
- {
- if (SafetyTable[i] - SafetyTable[i - 1] > maxSlope)
- SafetyTable[i] = SafetyTable[i - 1] + Value(maxSlope);
+ // 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]);
+ }
+
- if (SafetyTable[i] > Value(peak))
- SafetyTable[i] = Value(peak);
+ // trace_row() is an helper function used by tracing code to register the
+ // values of a single evaluation term.
+
+ void trace_row(const char *name, int idx) {
+
+ Score term_w = TracedTerms[WHITE][idx];
+ Score term_b = TracedTerms[BLACK][idx];
+
+ switch (idx) {
+ case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL:
+ TraceStream << std::setw(20) << name << " | --- --- | --- --- | "
+ << std::setw(6) << to_cp(mg_value(term_w)) << " "
+ << std::setw(6) << to_cp(eg_value(term_w)) << " \n";
+ break;
+ default:
+ TraceStream << std::setw(20) << name << " | " << std::noshowpos
+ << std::setw(5) << to_cp(mg_value(term_w)) << " "
+ << std::setw(5) << to_cp(eg_value(term_w)) << " | "
+ << std::setw(5) << to_cp(mg_value(term_b)) << " "
+ << std::setw(5) << to_cp(eg_value(term_b)) << " | "
+ << std::showpos
+ << std::setw(6) << to_cp(mg_value(term_w - term_b)) << " "
+ << std::setw(6) << to_cp(eg_value(term_w - term_b)) << " \n";
}
}
}
+
+
+/// trace_evaluate() is like evaluate() but instead of a value returns a string
+/// suitable to be print on stdout with the detailed descriptions and values of
+/// each evaluation term. Used mainly for debugging.
+
+std::string trace_evaluate(const Position& pos) {
+
+ Value margin;
+ std::string totals;
+
+ TraceStream.str("");
+ TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
+ memset(TracedTerms, 0, 2 * 16 * sizeof(Score));
+
+ do_evaluate<false, true>(pos, margin);
+
+ totals = TraceStream.str();
+ TraceStream.str("");
+
+ TraceStream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
+ << " | MG EG | MG EG | MG EG \n"
+ << "---------------------+-------------+-------------+---------------\n";
+
+ trace_row("Material, PST, Tempo", PST);
+ trace_row("Material imbalance", IMBALANCE);
+ trace_row("Pawns", PAWN);
+ trace_row("Knights", KNIGHT);
+ trace_row("Bishops", BISHOP);
+ trace_row("Rooks", ROOK);
+ trace_row("Queens", QUEEN);
+ trace_row("Mobility", MOBILITY);
+ trace_row("King safety", KING);
+ trace_row("Threats", THREAT);
+ trace_row("Passed pawns", PASSED);
+ trace_row("Unstoppable pawns", UNSTOPPABLE);
+ trace_row("Space", SPACE);
+
+ TraceStream << "---------------------+-------------+-------------+---------------\n";
+ trace_row("Total", TOTAL);
+ TraceStream << totals;
+
+ return TraceStream.str();
+}
projects / stockfish / blobdiff