X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fevaluate.cpp;h=652fb386683c13deeef0e82cd134f6403661b157;hb=2a98042c21fa2f3f5630c41a16b91539d7da3b87;hp=a5868f504b0b827af8e7320b780f57e6a2c2f656;hpb=fa0bffeafaa3554cb914249b4d032526e543359a;p=stockfish
diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index a5868f50..652fb386 100644
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -1,7 +1,7 @@
/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2009 Marco Costalba
+ Copyright (C) 2008-2013 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
@@ -17,40 +17,83 @@
along with this program. If not, see .
*/
-
-////
-//// Includes
-////
-
#include
-#include
+#include
+#include
+#include
#include "bitcount.h"
#include "evaluate.h"
#include "material.h"
#include "pawns.h"
-#include "scale.h"
#include "thread.h"
#include "ucioption.h"
+namespace {
-////
-//// Local definitions
-////
+ enum ExtendedPieceType { // Used for tracing
+ PST = 8, IMBALANCE, MOBILITY, THREAT, PASSED, UNSTOPPABLE, SPACE, TOTAL
+ };
-namespace {
+ namespace Tracing {
- const int Sign[2] = { 1, -1 };
+ Score scores[COLOR_NB][TOTAL + 1];
+ std::stringstream stream;
+
+ void add(int idx, Score term_w, Score term_b = SCORE_ZERO);
+ void row(const char* name, int idx);
+ std::string do_trace(const Position& pos);
+ }
+
+ // Struct EvalInfo contains various information computed and collected
+ // by the evaluation functions.
+ struct EvalInfo {
+
+ // Pointers to material and pawn hash table entries
+ Material::Entry* mi;
+ Pawns::Entry* pi;
+
+ // attackedBy[color][piece type] is a bitboard representing all squares
+ // attacked by a given color and piece type, attackedBy[color][ALL_PIECES]
+ // contains all squares attacked by the given color.
+ Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB];
+
+ // kingRing[color] is the zone around the king which is considered
+ // by the king safety evaluation. This consists of the squares directly
+ // adjacent to the king, and the three (or two, for a king on an edge file)
+ // squares two ranks in front of the king. For instance, if black's king
+ // is on g8, kingRing[BLACK] is a bitboard containing the squares f8, h8,
+ // f7, g7, h7, f6, g6 and h6.
+ Bitboard kingRing[COLOR_NB];
+
+ // kingAttackersCount[color] is the number of pieces of the given color
+ // which attack a square in the kingRing of the enemy king.
+ int kingAttackersCount[COLOR_NB];
+
+ // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
+ // given color which attack a square in the kingRing of the enemy king. The
+ // weights of the individual piece types are given by the variables
+ // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
+ // KnightAttackWeight in evaluate.cpp
+ int kingAttackersWeight[COLOR_NB];
+
+ // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
+ // directly adjacent to the king of the given color. Pieces which attack
+ // more than one square are counted multiple times. For instance, if black's
+ // king is on g8 and there's a white knight on g5, this knight adds
+ // 2 to kingAdjacentZoneAttacksCount[BLACK].
+ int kingAdjacentZoneAttacksCount[COLOR_NB];
+ };
// Evaluation grain size, must be a power of 2
- const int GrainSize = 8;
+ const int GrainSize = 4;
// Evaluation weights, initialized from UCI options
- int WeightMobilityMidgame, WeightMobilityEndgame;
- int WeightPawnStructureMidgame, WeightPawnStructureEndgame;
- int WeightPassedPawnsMidgame, WeightPassedPawnsEndgame;
- int WeightKingSafety[2];
- int WeightSpace;
+ 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
@@ -58,192 +101,118 @@ namespace {
// parameters at 100, which looks prettier.
//
// Values modified by Joona Kiiski
- const int WeightMobilityMidgameInternal = 248;
- const int WeightMobilityEndgameInternal = 271;
- const int WeightPawnStructureMidgameInternal = 233;
- const int WeightPawnStructureEndgameInternal = 201;
- const int WeightPassedPawnsMidgameInternal = 252;
- const int WeightPassedPawnsEndgameInternal = 259;
- const int WeightKingSafetyInternal = 247;
- const int WeightKingOppSafetyInternal = 259;
- const int WeightSpaceInternal = 46;
-
- // Mobility and outposts bonus modified by Joona Kiiski
- //
- // 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(-38), V(-25),V(-12), V(0), V(12), V(25), V(31), V(38), V(38)
- };
-
- const Value EndgameKnightMobilityBonus[] = {
- // 0 1 2 3 4 5 6 7 8
- V(-33), V(-23),V(-13), V(-3), V(7), V(17), V(22), V(27), V(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 Value MidgameBishopMobilityBonus[] = {
- // 0 1 2 3 4 5 6 7
- V(-25), V(-11), V(3), V(17), V(31), V(45), V(57), V(65),
- // 8 9 10 11 12 13 14 15
- V( 71), V( 74), V(76), V(78), V(79), V(80), V(81), V(81)
+ const Score WeightsInternal[] = {
+ S(289, 344), S(233, 201), S(221, 273), S(46, 0), S(271, 0), S(307, 0)
};
- const Value EndgameBishopMobilityBonus[] = {
- // 0 1 2 3 4 5 6 7
- V(-30), V(-16), V(-2), V(12), V(26), V(40), V(52), V(60),
- // 8 9 10 11 12 13 14 15
- V( 65), V( 69), V(71), V(73), V(74), V(75), V(76), V(76)
+ // MobilityBonus[PieceType][attacked] contains bonuses for middle and end
+ // game, indexed by piece type and number of attacked squares not occupied by
+ // friendly pieces.
+ const Score MobilityBonus[][32] = {
+ {}, {},
+ { S(-35,-30), S(-22,-20), S(-9,-10), S( 3, 0), S(15, 10), S(27, 20), // Knights
+ S( 37, 28), S( 42, 31), S(44, 33) },
+ { S(-22,-27), S( -8,-13), S( 6, 1), S(20, 15), S(34, 29), S(48, 43), // Bishops
+ S( 60, 55), S( 68, 63), S(74, 68), S(77, 72), S(80, 75), S(82, 77),
+ S( 84, 79), S( 86, 81), S(87, 82), S(87, 82) },
+ { S(-17,-33), S(-11,-16), S(-5, 0), S( 1, 16), S( 7, 32), S(13, 48), // Rooks
+ S( 18, 64), S( 22, 80), S(26, 96), S(29,109), S(31,115), S(33,119),
+ S( 35,122), S( 36,123), S(37,124), S(38,124) },
+ { S(-12,-20), S( -8,-13), S(-5, -7), S(-2, -1), S( 1, 5), S( 4, 11), // Queens
+ S( 7, 17), S( 10, 23), S(13, 29), S(16, 34), S(18, 38), S(20, 40),
+ S( 22, 41), S( 23, 41), S(24, 41), S(25, 41), S(25, 41), S(25, 41),
+ S( 25, 41), S( 25, 41), S(25, 41), S(25, 41), S(25, 41), S(25, 41),
+ S( 25, 41), S( 25, 41), S(25, 41), S(25, 41), S(25, 41), S(25, 41),
+ S( 25, 41), S( 25, 41) }
};
- // 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(-20), V(-14), V(-8), V(-2), V(4), V(10), V(14), V(19),
- // 8 9 10 11 12 13 14 15
- V( 23), V( 26), V(27), V(28), V(29), V(30), V(31), V(32)
- };
-
- const Value EndgameRookMobilityBonus[] = {
- // 0 1 2 3 4 5 6 7
- V(-36), V(-19), V(-3), V(13), V(29), V(46), V(62), V(79),
- // 8 9 10 11 12 13 14 15
- V( 95), V(106),V(111),V(114),V(116),V(117),V(118),V(118)
- };
-
- // 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(-3), V(-1), V( 1), V( 3), V( 5),
- // 8 9 10 11 12 13 14 15
- V( 8), V(10), V(12), V(15), V(16), V(17), V(18), V(20),
- // 16 17 18 19 20 21 22 23
- V( 20), V(20), V(20), V(20), V(20), V(20), V(20), V(20),
- // 24 25 26 27 28 29 30 31
- V( 20), V(20), V(20), V(20), V(20), V(20), V(20), V(20)
- };
-
- const Value EndgameQueenMobilityBonus[] = {
- // 0 1 2 3 4 5 6 7
- V(-18),V(-13), V(-7), V(-2), V( 3), V (8), V(13), V(19),
- // 8 9 10 11 12 13 14 15
- V( 23), V(27), V(32), V(34), V(35), V(35), V(35), V(35),
- // 16 17 18 19 20 21 22 23
- V( 35), V(35), V(35), V(35), V(35), V(35), V(35), V(35),
- // 24 25 26 27 28 29 30 31
- V( 35), V(35), V(35), V(35), V(35), V(35), V(35), V(35)
- };
-
- // Outpost bonuses for knights and bishops, indexed by square (from white's
- // point of view).
- const Value KnightOutpostBonus[64] = {
+ // Outpost[PieceType][Square] contains bonuses of knights and bishops, indexed
+ // by piece type and square (from white's point of view).
+ const Value Outpost[][SQUARE_NB] = {
+ {
// A B C D E F G H
- V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 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
+ 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) }
};
- 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(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
+ // Threat[attacking][attacked] contains bonuses according to which piece
+ // type attacks which one.
+ const Score Threat[][PIECE_TYPE_NB] = {
+ {}, {},
+ { S(0, 0), S( 7, 39), S( 0, 0), S(24, 49), S(41,100), S(41,100) }, // KNIGHT
+ { S(0, 0), S( 7, 39), S(24, 49), S( 0, 0), S(41,100), S(41,100) }, // BISHOP
+ { S(0, 0), S( 0, 22), S(15, 49), S(15, 49), S( 0, 0), S(24, 49) }, // ROOK
+ { S(0, 0), S(15, 39), S(15, 39), S(15, 39), S(15, 39), S( 0, 0) } // QUEEN
};
- // Bonus for unstoppable passed pawns
- const Value UnstoppablePawnValue = Value(0x500);
-
- // Rooks and queens on the 7th rank (modified by Joona Kiiski)
- const Value MidgameRookOn7thBonus = Value(47);
- const Value EndgameRookOn7thBonus = Value(98);
- const Value MidgameQueenOn7thBonus = Value(27);
- const Value EndgameQueenOn7thBonus = Value(54);
-
- // Rooks on open files (modified by Joona Kiiski)
- const Value RookOpenFileBonus = Value(43);
- const Value RookHalfOpenFileBonus = Value(19);
-
- // Penalty for rooks trapped inside a friendly king which has lost the
- // right to castle.
- const Value TrappedRookPenalty = Value(180);
+ // ThreatenedByPawn[PieceType] contains a penalty according to which piece
+ // type is attacked by an enemy pawn.
+ const Score ThreatenedByPawn[] = {
+ S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
+ };
- // Penalty for a bishop on a7/h7 (a2/h2 for black) which is trapped by
- // enemy pawns.
- const Value TrappedBishopA7H7Penalty = Value(300);
+ #undef S
- // 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))
- };
+ const Score Tempo = make_score(24, 11);
+ const Score BishopPin = make_score(66, 11);
+ const Score RookOn7th = make_score(11, 20);
+ const Score QueenOn7th = make_score( 3, 8);
+ const Score RookOnPawn = make_score(10, 28);
+ const Score QueenOnPawn = make_score( 4, 20);
+ const Score RookOpenFile = make_score(43, 21);
+ const Score RookSemiopenFile = make_score(19, 10);
+ const Score BishopPawns = make_score( 8, 12);
+ const Score UndefendedMinor = make_score(25, 10);
+ const Score TrappedRook = make_score(90, 0);
// 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 Value TrappedBishopA1H1Penalty = Value(100);
+ const Score TrappedBishopA1H1 = make_score(50, 50);
- // 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 area of the board which is consdered by
- // the space evaluation. In the middle game, each side is given a bonus
+ // 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<
- Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID);
+ template
+ Value do_evaluate(const Position& pos, Value& margin);
- template
- void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei);
+ template
+ void init_eval_info(const Position& pos, EvalInfo& ei);
- template
- void evaluate_king(const Position& pos, EvalInfo& ei);
+ template
+ Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility);
- template
- void evaluate_space(const Position& pos, EvalInfo& ei);
+ template
+ Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]);
- 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);
- inline Value apply_weight(Value v, int w);
- Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]);
- int weight_option(const std::string& opt, int weight);
- void init_safety();
-}
+ template
+ Score evaluate_threats(const Position& pos, EvalInfo& ei);
+ template
+ Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
-////
-//// Functions
-////
+ template
+ int evaluate_space(const Position& pos, EvalInfo& ei);
-/// 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) {
+ Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
- return CpuHasPOPCNT ? do_evaluate(pos, ei, threadID)
- : do_evaluate(pos, ei, threadID);
+ Value interpolate(const Score& v, Phase ph, ScaleFactor sf);
+ Score apply_weight(Score v, Score w);
+ Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
+ double to_cp(Value v);
}
-namespace {
-
-template
-Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID) {
- assert(pos.is_ok());
- assert(threadID >= 0 && threadID < THREAD_MAX);
+namespace Eval {
- memset(&ei, 0, sizeof(EvalInfo));
+ /// 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.
- // 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();
+ Value evaluate(const Position& pos, Value& margin) {
+ return do_evaluate(pos, margin);
+ }
- // Probe the material hash table
- ei.mi = MaterialTable[threadID]->get_material_info(pos);
- ei.mgValue += ei.mi->material_value();
- ei.egValue += ei.mi->material_value();
- // If we have a specialized evaluation function for the current material
- // configuration, call it and return
- if (ei.mi->specialized_eval_exists())
- return ei.mi->evaluate(pos);
+ /// trace() is like evaluate() but instead of a value returns a string suitable
+ /// to be print on stdout with the detailed descriptions and values of each
+ /// evaluation term. Used mainly for debugging.
+ std::string trace(const Position& pos) {
+ return Tracing::do_trace(pos);
+ }
- // 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);
- // 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.attacks_from(pos.king_square(WHITE));
- ei.attackedBy[BLACK][KING] = pos.attacks_from(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.pieces(PAWN, WHITE) << 9) & ~FileABB) | ((pos.pieces(PAWN, WHITE) << 7) & ~FileHBB);
- ei.attackedBy[BLACK][PAWN] = ((pos.pieces(PAWN, BLACK) >> 7) & ~FileABB) | ((pos.pieces(PAWN, BLACK) >> 9) & ~FileHBB);
- Bitboard b1 = ei.attackedBy[WHITE][PAWN] & ei.attackedBy[BLACK][KING];
- Bitboard b2 = ei.attackedBy[BLACK][PAWN] & ei.attackedBy[WHITE][KING];
- if (b1)
- ei.kingAttackersCount[WHITE] = count_1s_max_15(b1)/2;
-
- if (b2)
- ei.kingAttackersCount[BLACK] = count_1s_max_15(b2)/2;
-
- // Evaluate pieces
- evaluate_pieces_of_color(pos, ei);
- evaluate_pieces_of_color(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(pos, ei);
- evaluate_king(pos, ei);
-
- // 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);
-
- Phase phase = pos.game_phase();
-
- // 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)
+ /// init() computes evaluation weights from the corresponding UCI parameters
+ /// and setup king tables.
- ei.mgValue += ei.pi->queenside_storm_value(WHITE)
- - ei.pi->kingside_storm_value(BLACK);
+ void init() {
- else if ( square_file(pos.king_square(WHITE)) <= FILE_D
- && square_file(pos.king_square(BLACK)) >= FILE_E)
+ Weights[Mobility] = weight_option("Mobility (Midgame)", "Mobility (Endgame)", WeightsInternal[Mobility]);
+ Weights[PawnStructure] = weight_option("Pawn Structure (Midgame)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
+ Weights[PassedPawns] = weight_option("Passed Pawns (Midgame)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
+ Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
+ Weights[KingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
+ Weights[KingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
- ei.mgValue += ei.pi->kingside_storm_value(WHITE)
- - ei.pi->queenside_storm_value(BLACK);
+ const int MaxSlope = 30;
+ const int Peak = 1280;
- // Evaluate space for both sides
- if (ei.mi->space_weight() > 0)
+ for (int t = 0, i = 1; i < 100; i++)
{
- evaluate_space(pos, ei);
- evaluate_space(pos, ei);
+ t = std::min(Peak, std::min(int(0.4 * i * i), t + MaxSlope));
+
+ KingDanger[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]);
+ KingDanger[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]);
}
}
- // Mobility
- ei.mgValue += apply_weight(ei.mgMobility, WeightMobilityMidgame);
- ei.egValue += apply_weight(ei.egMobility, WeightMobilityEndgame);
+} // namespace Eval
- // If we don't already have an unusual scale factor, check for opposite
- // colored bishop endgames, and use a lower scale for those
- if ( phase < PHASE_MIDGAME
- && pos.opposite_colored_bishops()
- && ( (factor[WHITE] == SCALE_FACTOR_NORMAL && ei.egValue > Value(0))
- || (factor[BLACK] == SCALE_FACTOR_NORMAL && ei.egValue < Value(0))))
- {
- ScaleFactor sf;
- // Only the two bishops ?
- if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
- && pos.non_pawn_material(BLACK) == BishopValueMidgame)
- {
- // Check for KBP vs KB with only a single pawn that is almost
- // certainly a draw or at least two pawns.
- bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
- sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
- }
- else
- // Endgame with opposite-colored bishops, but also other pieces. Still
- // a bit drawish, but not as drawish as with only the two bishops.
- sf = ScaleFactor(50);
+namespace {
- if (factor[WHITE] == SCALE_FACTOR_NORMAL)
- factor[WHITE] = sf;
- if (factor[BLACK] == SCALE_FACTOR_NORMAL)
- factor[BLACK] = sf;
- }
+template
+Value do_evaluate(const Position& pos, Value& margin) {
- // Interpolate between the middle game and the endgame score
- Color stm = pos.side_to_move();
+ assert(!pos.checkers());
- Value v = Sign[stm] * scale_by_game_phase(ei.mgValue, ei.egValue, phase, factor);
+ EvalInfo ei;
+ Value margins[COLOR_NB];
+ Score score, mobilityWhite, mobilityBlack;
+ Thread* th = pos.this_thread();
- return (ei.mateThreat[stm] == MOVE_NONE ? v : 8 * QueenValueMidgame - v);
-}
+ // 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;
-} // namespace
+ // Initialize score by reading the incrementally updated scores included
+ // in the position object (material + piece square tables) and adding
+ // Tempo bonus. Score is computed from the point of view of white.
+ score = pos.psq_score() + (pos.side_to_move() == WHITE ? Tempo : -Tempo);
-/// 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?
+ // Probe the material hash table
+ ei.mi = Material::probe(pos, th->materialTable, th->endgames);
+ score += ei.mi->material_value();
-Value quick_evaluate(const Position &pos) {
+ // If we have a specialized evaluation function for the current material
+ // configuration, call it and return.
+ if (ei.mi->specialized_eval_exists())
+ {
+ margin = VALUE_ZERO;
+ return ei.mi->evaluate(pos);
+ }
- assert(pos.is_ok());
+ // Probe the pawn hash table
+ ei.pi = Pawns::probe(pos, th->pawnsTable);
+ score += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
- static const
- ScaleFactor sf[2] = {SCALE_FACTOR_NORMAL, SCALE_FACTOR_NORMAL};
+ // Initialize attack and king safety bitboards
+ init_eval_info(pos, ei);
+ init_eval_info(pos, ei);
- Value mgv = pos.mg_value();
- Value egv = pos.eg_value();
- Phase ph = pos.game_phase();
- Color stm = pos.side_to_move();
+ // Evaluate pieces and mobility
+ score += evaluate_pieces_of_color(pos, ei, mobilityWhite)
+ - evaluate_pieces_of_color(pos, ei, mobilityBlack);
- return Sign[stm] * scale_by_game_phase(mgv, egv, ph, sf);
-}
+ score += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
+ // Evaluate kings after all other pieces because we need complete attack
+ // information when computing the king safety evaluation.
+ score += evaluate_king(pos, ei, margins)
+ - evaluate_king(pos, ei, margins);
-/// init_eval() initializes various tables used by the evaluation function
+ // Evaluate tactical threats, we need full attack information including king
+ score += evaluate_threats(pos, ei)
+ - evaluate_threats(pos, ei);
-void init_eval(int threads) {
+ // Evaluate passed pawns, we need full attack information including king
+ score += evaluate_passed_pawns(pos, ei)
+ - evaluate_passed_pawns(pos, ei);
- assert(threads <= THREAD_MAX);
+ // If one side has only a king, check whether exists any unstoppable passed pawn
+ if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
+ score += evaluate_unstoppable_pawns(pos, ei);
- for (int i = 0; i < THREAD_MAX; i++)
+ // Evaluate space for both sides, only in middle-game.
+ if (ei.mi->space_weight())
{
- 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);
+ int s = evaluate_space(pos, ei) - evaluate_space(pos, ei);
+ score += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]);
}
-}
+ // Scale winning side if position is more drawish that what it appears
+ ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE)
+ : ei.mi->scale_factor(pos, BLACK);
-/// quit_eval() releases heap-allocated memory at program termination
-
-void quit_eval() {
-
- for (int i = 0; i < THREAD_MAX; i++)
+ // If we don't already have an unusual scale factor, check for opposite
+ // colored bishop endgames, and use a lower scale for those.
+ if ( ei.mi->game_phase() < PHASE_MIDGAME
+ && pos.opposite_bishops()
+ && sf == SCALE_FACTOR_NORMAL)
{
- delete PawnTable[i];
- delete MaterialTable[i];
- PawnTable[i] = NULL;
- MaterialTable[i] = NULL;
+ // Only the two bishops ?
+ if ( pos.non_pawn_material(WHITE) == BishopValueMg
+ && pos.non_pawn_material(BLACK) == BishopValueMg)
+ {
+ // Check for KBP vs KB with only a single pawn that is almost
+ // certainly a draw or at least two pawns.
+ bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
+ sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
+ }
+ else
+ // Endgame with opposite-colored bishops, but also other pieces. Still
+ // a bit drawish, but not as drawish as with only the two bishops.
+ sf = ScaleFactor(50);
}
-}
-
-
-/// read_weights() reads evaluation weights from the corresponding UCI parameters
-void read_weights(Color us) {
+ margin = margins[pos.side_to_move()];
+ Value v = interpolate(score, ei.mi->game_phase(), sf);
- Color them = opposite_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);
- WeightSpace = weight_option("Space", WeightSpaceInternal);
- 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 WeightKingSafety[us] and WeightKingSafety[them] by their average.
- if (get_option_value_bool("UCI_AnalyseMode"))
+ // In case of tracing add all single evaluation contributions for both white and black
+ if (Trace)
{
- WeightKingSafety[us] = (WeightKingSafety[us] + WeightKingSafety[them]) / 2;
- WeightKingSafety[them] = WeightKingSafety[us];
+ Tracing::add(PST, pos.psq_score());
+ Tracing::add(IMBALANCE, ei.mi->material_value());
+ Tracing::add(PAWN, ei.pi->pawns_value());
+ Tracing::add(UNSTOPPABLE, evaluate_unstoppable_pawns(pos, ei));
+ Score w = make_score(ei.mi->space_weight() * evaluate_space(pos, ei), 0);
+ Score b = make_score(ei.mi->space_weight() * evaluate_space(pos, ei), 0);
+ Tracing::add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
+ Tracing::add(TOTAL, score);
+ Tracing::stream << "\nUncertainty margin: White: " << to_cp(margins[WHITE])
+ << ", Black: " << to_cp(margins[BLACK])
+ << "\nScaling: " << std::noshowpos
+ << std::setw(6) << 100.0 * ei.mi->game_phase() / 128.0 << "% MG, "
+ << std::setw(6) << 100.0 * (1.0 - ei.mi->game_phase() / 128.0) << "% * "
+ << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
+ << "Total evaluation: " << to_cp(v);
}
- init_safety();
+
+ return pos.side_to_move() == WHITE ? v : -v;
}
-namespace {
+ // init_eval_info() initializes king bitboards for given color adding
+ // pawn attacks. To be done at the beginning of the evaluation.
- // evaluate_mobility() computes mobility and attacks for every piece
-
- template
- int evaluate_mobility(const Position& pos, const Bitboard& mob_bb, EvalInfo& ei) {
+ template
+ void init_eval_info(const Position& pos, EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
- static const int AttackWeight[] = { 0, 0, KnightAttackWeight, BishopAttackWeight, RookAttackWeight, QueenAttackWeight };
- static const Value* MgBonus[] = { 0, 0, MidgameKnightMobilityBonus, MidgameBishopMobilityBonus, MidgameRookMobilityBonus, MidgameQueenMobilityBonus };
- static const Value* EgBonus[] = { 0, 0, EndgameKnightMobilityBonus, EndgameBishopMobilityBonus, EndgameRookMobilityBonus, EndgameQueenMobilityBonus };
- // Update attack info
- ei.attackedBy[Us][Piece] |= mob_bb;
+ Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from(pos.king_square(Them));
+ ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
- // King attacks
- if (mob_bb & 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) > QueenValueMg + PawnValueMg)
{
- ei.kingAttackersCount[Us]++;
- ei.kingAttackersWeight[Us] += AttackWeight[Piece];
- Bitboard b = (mob_bb & ei.attackedBy[Them][KING]);
- if (b)
- ei.kingAdjacentZoneAttacksCount[Us] += count_1s_max_15(b);
- }
-
- // Remove squares protected by enemy pawns or occupied by our pieces
- Bitboard b = mob_bb & ~ei.attackedBy[Them][PAWN] & ~pos.pieces_of_color(Us);
-
- // Mobility
- int mob = (Piece != QUEEN ? count_1s_max_15(b) : count_1s(b));
-
- ei.mgMobility += Sign[Us] * MgBonus[Piece][mob];
- ei.egMobility += Sign[Us] * EgBonus[Piece][mob];
- return mob;
+ ei.kingRing[Them] = (b | (Us == WHITE ? b >> 8 : b << 8));
+ b &= ei.attackedBy[Us][PAWN];
+ ei.kingAttackersCount[Us] = b ? popcount(b) / 2 : 0;
+ ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
+ } else
+ ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0;
}
// evaluate_outposts() evaluates bishop and knight outposts squares
template
- 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 = Outpost[Piece == BISHOP][relative_square(Us, s)];
// Increase bonus if supported by pawn, especially if the opponent has
- // no minor piece which can exchange the outpost piece
- if (bonus && (pos.attacks_from(s, Them) & pos.pieces(PAWN, Us)))
+ // no minor piece which can exchange the outpost piece.
+ if (bonus && (ei.attackedBy[Us][PAWN] & s))
{
- if ( pos.pieces(KNIGHT, Them) == EmptyBoardBB
- && (SquaresByColorBB[square_color(s)] & pos.pieces(BISHOP, Them)) == EmptyBoardBB)
+ if ( !pos.pieces(Them, KNIGHT)
+ && !(same_color_squares(s) & pos.pieces(Them, BISHOP)))
bonus += bonus + bonus / 2;
else
bonus += bonus / 2;
}
- ei.mgValue += Sign[Us] * bonus;
- ei.egValue += Sign[Us] * bonus;
+ return make_score(bonus, bonus);
}
// evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
- template
- void evaluate_pieces(const Position& pos, EvalInfo& ei) {
+ template
+ Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
- Bitboard mob_bb;
- Square s, ksq;
- int mob;
- File f;
+ Bitboard b;
+ Square s;
+ Score score = SCORE_ZERO;
const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Square* ptr = pos.piece_list_begin(Us, Piece);
+ const Square* pl = pos.piece_list(Us, Piece);
- while ((s = *ptr++) != SQ_NONE)
+ ei.attackedBy[Us][Piece] = 0;
+
+ while ((s = *pl++) != SQ_NONE)
{
- if (Piece == KNIGHT || Piece == QUEEN)
- mob_bb = pos.attacks_from(s);
- else if (Piece == BISHOP)
- mob_bb = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
- else if (Piece == ROOK)
- mob_bb = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
- else
- assert(false);
+ // Find attacked squares, including x-ray attacks for bishops and rooks
+ b = Piece == BISHOP ? attacks_bb(s, pos.pieces() ^ pos.pieces(Us, QUEEN))
+ : Piece == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN))
+ : pos.attacks_from(s);
- // Attacks and mobility
- mob = evaluate_mobility(pos, mob_bb, ei);
+ ei.attackedBy[Us][Piece] |= b;
- // Bishop and knight outposts squares
- if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Them))
- evaluate_outposts(pos, ei, s);
+ if (b & ei.kingRing[Them])
+ {
+ ei.kingAttackersCount[Us]++;
+ ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
+ Bitboard bb = (b & ei.attackedBy[Them][KING]);
+ if (bb)
+ ei.kingAdjacentZoneAttacksCount[Us] += popcount(bb);
+ }
+
+ int mob = popcount(b & mobilityArea);
+ mobility += MobilityBonus[Piece][mob];
- // Special patterns: trapped bishops on a7/h7/a2/h2
- // and trapped bishops on a1/h1/a8/h8 in Chess960.
+ // 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 (ei.attackedBy[Them][PAWN] & s)
+ score -= ThreatenedByPawn[Piece];
+
+ // Otherwise give a bonus if we are a bishop and can pin a piece or can
+ // give a discovered check through an x-ray attack.
+ else if ( Piece == BISHOP
+ && (PseudoAttacks[Piece][pos.king_square(Them)] & s)
+ && !more_than_one(BetweenBB[s][pos.king_square(Them)] & pos.pieces()))
+ score += BishopPin;
+
+ // Penalty for bishop with same coloured pawns
if (Piece == BISHOP)
- {
- if (bit_is_set(MaskA7H7[Us], s))
- evaluate_trapped_bishop_a7h7(pos, s, Us, ei);
+ score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s);
- if (Chess960 && bit_is_set(MaskA1H1[Us], s))
- evaluate_trapped_bishop_a1h1(pos, s, Us, ei);
- }
+ // Bishop and knight outposts squares
+ if ( (Piece == BISHOP || Piece == KNIGHT)
+ && !(pos.pieces(Them, PAWN) & attack_span_mask(Us, s)))
+ score += evaluate_outposts(pos, ei, s);
- if (Piece == ROOK || Piece == QUEEN)
+ if ( (Piece == ROOK || Piece == QUEEN)
+ && relative_rank(Us, s) >= RANK_5)
{
- // Queen or rook on 7th rank
+ // Major piece on 7th rank and enemy king trapped on 8th
if ( relative_rank(Us, s) == RANK_7
&& relative_rank(Us, pos.king_square(Them)) == RANK_8)
- {
- ei.mgValue += Sign[Us] * (Piece == ROOK ? MidgameRookOn7thBonus : MidgameQueenOn7thBonus);
- ei.egValue += Sign[Us] * (Piece == ROOK ? EndgameRookOn7thBonus : EndgameQueenOn7thBonus);
- }
+ score += Piece == ROOK ? RookOn7th : QueenOn7th;
+
+ // Major piece attacking enemy pawns on the same rank
+ Bitboard pawns = pos.pieces(Them, PAWN) & rank_bb(s);
+ if (pawns)
+ score += popcount(pawns) * (Piece == ROOK ? RookOnPawn : QueenOnPawn);
}
// 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))
- {
- ei.mgValue += Sign[Us] * RookOpenFileBonus;
- ei.egValue += Sign[Us] * RookOpenFileBonus;
- }
- else
- {
- ei.mgValue += Sign[Us] * RookHalfOpenFileBonus;
- ei.egValue += Sign[Us] * RookHalfOpenFileBonus;
- }
- }
+ // Give a bonus for a rook on a open or semi-open file
+ if (ei.pi->semiopen(Us, file_of(s)))
+ score += ei.pi->semiopen(Them, file_of(s)) ? RookOpenFile : RookSemiopenFile;
- // 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))
+ if (mob > 6 || ei.pi->semiopen(Us, file_of(s)))
continue;
- ksq = pos.king_square(Us);
+ Square 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 -= pos.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 -= pos.can_castle(Us)? Sign[Us] * ((TrappedRookPenalty - mob * 16) / 2)
- : Sign[Us] * (TrappedRookPenalty - mob * 16);
- }
+ // Penalize rooks which are trapped inside a king. Penalize more if
+ // king has lost right to castle.
+ if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
+ && (rank_of(ksq) == rank_of(s) || relative_rank(Us, ksq) == RANK_1)
+ && !ei.pi->semiopen_on_side(Us, file_of(ksq), file_of(ksq) < FILE_E))
+ score -= (TrappedRook - make_score(mob * 8, 0)) * (pos.can_castle(Us) ? 1 : 2);
+ }
+
+ // 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 ( Piece == BISHOP
+ && pos.is_chess960()
+ && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
+ {
+ const enum Piece P = make_piece(Us, PAWN);
+ Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
+ if (pos.piece_on(s + d) == P)
+ score -= !pos.is_empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4
+ : pos.piece_on(s + d + d) == P ? TrappedBishopA1H1 * 2
+ : TrappedBishopA1H1;
}
}
+
+ if (Trace)
+ Tracing::scores[Us][Piece] = score;
+
+ return score;
+ }
+
+
+ // evaluate_threats<>() assigns bonuses according to the type of attacking piece
+ // and the type of attacked one.
+
+ template
+ Score evaluate_threats(const Position& pos, EvalInfo& ei) {
+
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+
+ Bitboard b, undefendedMinors, weakEnemies;
+ Score score = SCORE_ZERO;
+
+ // Undefended minors get penalized even if not under attack
+ undefendedMinors = pos.pieces(Them, BISHOP, KNIGHT)
+ & ~ei.attackedBy[Them][ALL_PIECES];
+
+ if (undefendedMinors)
+ score += UndefendedMinor;
+
+ // Enemy pieces not defended by a pawn and under our attack
+ weakEnemies = pos.pieces(Them)
+ & ~ei.attackedBy[Them][PAWN]
+ & ei.attackedBy[Us][ALL_PIECES];
+
+ // Add bonus according to type of attacked enemy piece and to the
+ // type of attacking piece, from knights to queens. Kings are not
+ // considered because are already handled in king evaluation.
+ if (weakEnemies)
+ for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
+ {
+ b = ei.attackedBy[Us][pt1] & weakEnemies;
+ if (b)
+ for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
+ if (b & pos.pieces(pt2))
+ score += Threat[pt1][pt2];
+ }
+
+ if (Trace)
+ Tracing::scores[Us][THREAT] = score;
+
+ return score;
}
// evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
// pieces of a given color.
- template
- void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei) {
+ template
+ Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) {
+
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+
+ Score score = mobility = SCORE_ZERO;
+
+ // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
+ const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces(Us, PAWN, KING));
+
+ score += evaluate_pieces(pos, ei, mobility, mobilityArea);
+ score += evaluate_pieces(pos, ei, mobility, mobilityArea);
+ score += evaluate_pieces(pos, ei, mobility, mobilityArea);
+ score += evaluate_pieces(pos, ei, mobility, mobilityArea);
- evaluate_pieces(pos, ei);
- evaluate_pieces(pos, ei);
- evaluate_pieces(pos, ei);
- evaluate_pieces(pos, ei);
+ // Sum up all attacked squares
+ ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
+ | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
+ | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
+ if (Trace)
+ Tracing::scores[Us][MOBILITY] = apply_weight(mobility, Weights[Mobility]);
- // 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 score;
}
// evaluate_king<>() assigns bonuses and penalties to a king of a given color
- template
- void evaluate_king(const Position& pos, EvalInfo& ei) {
+ template
+ Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Square s = pos.king_square(Us);
- int shelter = 0;
- // King shelter
- if (relative_rank(Us, s) <= RANK_4)
- {
- shelter = ei.pi->get_king_shelter(pos, Us, s);
- ei.mgValue += Sign[Us] * Value(shelter);
- }
+ Bitboard undefended, b, b1, b2, safe;
+ int attackUnits;
+ const Square ksq = pos.king_square(Us);
+
+ // King shelter and enemy pawns storm
+ Score score = ei.pi->king_safety(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?
- bool sente = (Them == pos.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 = pos.occupied_squares(), b, b2;
-
- // 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.
- 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 >> 5);
-
- // Analyse safe queen contact checks
- b = undefended & ei.attacked_by(Them, QUEEN) & ~pos.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][ALL_PIECES] & 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 KingDanger[] array. The initial value is based on the
+ // number and types of the enemy's attacking pieces, the number of
+ // attacked and undefended squares around our king, the square of the
+ // king, and the quality of the pawn shelter.
+ attackUnits = std::min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
+ + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount(undefended))
+ + KingExposed[relative_square(Us, ksq)]
+ - mg_value(score) / 32;
+
+ // Analyse enemy's safe queen contact checks. First find undefended
+ // squares around the king attacked by enemy queen...
+ b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(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 && !pos.is_check())
- {
- Bitboard escapeSquares =
- pos.attacks_from(s) & ~pos.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 < pos.piece_count(Them, QUEEN); i++)
- {
- from = pos.piece_list(Them, QUEEN, i);
- if ( bit_is_set(pos.attacks_from(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)))
-
- 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 += QueenContactCheck
+ * popcount(b)
+ * (Them == pos.side_to_move() ? 2 : 1);
}
- }
- // Analyse safe distance checks
- if (QueenCheckBonus > 0 || RookCheckBonus > 0)
- {
- b = pos.attacks_from(s) & ~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(Them);
- // Queen checks
- b2 = b & ei.attacked_by(Them, QUEEN);
- if (b2)
- attackUnits += QueenCheckBonus * count_1s_max_15(b2);
+ // Consider only squares where the enemy rook gives check
+ b &= PseudoAttacks[ROOK][ksq];
- // Rook checks
- b2 = b & ei.attacked_by(Them, ROOK);
- if (b2)
- attackUnits += RookCheckBonus * count_1s_max_15(b2);
- }
- if (QueenCheckBonus > 0 || BishopCheckBonus > 0)
- {
- b = pos.attacks_from(s) & ~pos.pieces_of_color(Them) & ~ei.attacked_by(Us);
+ 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 += RookContactCheck
+ * popcount(b)
+ * (Them == pos.side_to_move() ? 2 : 1);
+ }
- // Queen checks
- b2 = b & ei.attacked_by(Them, QUEEN);
- if (b2)
- attackUnits += QueenCheckBonus * count_1s_max_15(b2);
+ // Analyse enemy's safe distance checks for sliders and knights
+ safe = ~(pos.pieces(Them) | ei.attackedBy[Us][ALL_PIECES]);
- // Bishop checks
- b2 = b & ei.attacked_by(Them, BISHOP);
- if (b2)
- attackUnits += BishopCheckBonus * count_1s_max_15(b2);
- }
- if (KnightCheckBonus > 0)
- {
- b = pos.attacks_from(s) & ~pos.pieces_of_color(Them) & ~ei.attacked_by(Us);
+ b1 = pos.attacks_from(ksq) & safe;
+ b2 = pos.attacks_from(ksq) & safe;
- // Knight checks
- b2 = b & ei.attacked_by(Them, KNIGHT);
- if (b2)
- attackUnits += KnightCheckBonus * count_1s_max_15(b2);
- }
+ // Enemy queen safe checks
+ b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
+ if (b)
+ attackUnits += QueenCheck * popcount(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);
+ // Enemy rooks safe checks
+ b = b1 & ei.attackedBy[Them][ROOK];
if (b)
- attackUnits += DiscoveredCheckBonus * count_1s_max_15(b) * (sente ? 2 : 1);
- }
+ attackUnits += RookCheck * popcount(b);
+
+ // Enemy bishops safe checks
+ b = b2 & ei.attackedBy[Them][BISHOP];
+ if (b)
+ attackUnits += BishopCheck * popcount(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[Us] * v;
-
- if (Us == pos.side_to_move())
- ei.futilityMargin += v;
+ // Enemy knights safe checks
+ b = pos.attacks_from(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
+ if (b)
+ attackUnits += KnightCheck * popcount(b);
+
+ // To index KingDanger[] attackUnits must be in [0, 99] range
+ attackUnits = std::min(99, std::max(0, attackUnits));
+
+ // Finally, extract the king danger score from the KingDanger[]
+ // array and subtract the score from evaluation. Set also margins[]
+ // value that will be used for pruning because this value can sometimes
+ // be very big, and so capturing a single attacking piece can therefore
+ // result in a score change far bigger than the value of the captured piece.
+ score -= KingDanger[Us == Search::RootColor][attackUnits];
+ margins[Us] += mg_value(KingDanger[Us == Search::RootColor][attackUnits]);
}
+
+ if (Trace)
+ Tracing::scores[Us][KING] = score;
+
+ return score;
}
- // evaluate_passed_pawns() evaluates the passed pawns for both sides
+ // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
- void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
+ template
+ Score 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.pieces(PAWN, us), b2, b3, b4;
+ Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
+ Score score = SCORE_ZERO;
- while (b)
- {
- Square s = pop_1st_bit(&b);
+ b = ei.pi->passed_pawns(Us);
- assert(pos.piece_on(s) == piece_of_color_and_type(us, PAWN));
- assert(pos.pawn_is_passed(us, s));
+ while (b)
+ {
+ Square s = pop_lsb(&b);
- int r = int(relative_rank(us, s) - RANK_2);
- int tr = Max(0, r * (r - 1));
- Square blockSq = s + pawn_push(us);
+ assert(pos.pawn_is_passed(Us, s));
- // Base bonus based on rank
- Value mbonus = Value(20 * tr);
- Value ebonus = Value(10 + r * r * 10);
+ int r = int(relative_rank(Us, s) - RANK_2);
+ int rr = r * (r - 1);
- // Adjust bonus based on king proximity
- if (tr != 0)
- {
- 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);
+ // Base bonus based on rank
+ Value mbonus = Value(17 * rr);
+ Value ebonus = Value(7 * (rr + r + 1));
- // 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 there is an enemy rook or queen attacking the pawn from behind,
- // add all X-ray attacks by the rook or queen.
- if ( bit_is_set(ei.attacked_by(them,ROOK) | ei.attacked_by(them,QUEEN),s)
- && (squares_behind(us, s) & pos.pieces(ROOK, QUEEN, them)))
- b3 = b2;
-
- // Squares attacked or occupied by enemy pieces
- b3 |= (b2 & pos.pieces_of_color(them));
-
- // There are no enemy pawns in the pawn's path
- assert((b2 & pos.pieces(PAWN, them)) == EmptyBoardBB);
-
- // 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!
- ebonus += Value(tr * (b2 == b4 ? 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));
-
- // 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 (rr)
+ {
+ Square blockSq = s + pawn_push(Us);
+
+ // Adjust bonus based on kings proximity
+ ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 5 * rr);
+ ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 2 * rr);
- // If the pawn is supported by a friendly pawn, increase bonus
- b2 = pos.pieces(PAWN, us) & neighboring_files_bb(s);
- if (b2 & rank_bb(s))
- ebonus += Value(r * 20);
- else if (pos.attacks_from(s, them) & b2)
- ebonus += Value(r * 12);
+ // If blockSq is not the queening square then consider also a second push
+ if (rank_of(blockSq) != (Us == WHITE ? RANK_8 : RANK_1))
+ ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
- // If the other side has only a king, check whether the pawn is
- // unstoppable
- if (pos.non_pawn_material(them) == Value(0))
+ // If the pawn is free to advance, increase bonus
+ if (pos.is_empty(blockSq))
{
- Square qsq;
- int d;
+ squaresToQueen = forward_bb(Us, s);
+ defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES];
+
+ // If there is an enemy rook or queen attacking the pawn from behind,
+ // add all X-ray attacks by the rook or queen. Otherwise consider only
+ // the squares in the pawn's path attacked or occupied by the enemy.
+ if ( (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN))
+ && (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN) & pos.attacks_from(s)))
+ unsafeSquares = squaresToQueen;
+ else
+ unsafeSquares = squaresToQueen & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
- 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());
+ // If there aren't enemy attacks huge bonus, a bit smaller if at
+ // least block square is not attacked, otherwise smallest bonus.
+ int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 3;
- 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);
- }
- }
- }
- // 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.pieces(ROOK, QUEEN, them))
- ebonus -= ebonus / 4;
- }
+ // Big bonus if the path to queen is fully defended, a bit less
+ // if at least block square is defended.
+ if (defendedSquares == squaresToQueen)
+ k += 6;
+
+ else if (defendedSquares & blockSq)
+ k += (unsafeSquares & defendedSquares) == unsafeSquares ? 4 : 2;
- // 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);
+ mbonus += Value(k * rr), ebonus += Value(k * rr);
+ }
+ } // rr != 0
+
+ // Increase the bonus if the passed pawn is supported by a friendly pawn
+ // on the same rank and a bit smaller if it's on the previous rank.
+ supportingPawns = pos.pieces(Us, PAWN) & adjacent_files_bb(file_of(s));
+ if (supportingPawns & rank_bb(s))
+ ebonus += Value(r * 20);
+
+ else if (supportingPawns & rank_bb(s - pawn_push(Us)))
+ ebonus += Value(r * 12);
+
+ // Rook pawns are a special case: They are sometimes worse, and
+ // sometimes better than other passed pawns. It is difficult to find
+ // good rules for determining whether they are good or bad. For now,
+ // we try the following: Increase the value for rook pawns if the
+ // other side has no pieces apart from a knight, and decrease the
+ // value if the other side has a rook or queen.
+ if (file_of(s) == FILE_A || file_of(s) == FILE_H)
+ {
+ if (pos.non_pawn_material(Them) <= KnightValueMg)
+ ebonus += ebonus / 4;
+ else if (pos.pieces(Them, ROOK, QUEEN))
+ ebonus -= ebonus / 4;
}
- }
+ score += make_score(mbonus, ebonus);
- // 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.
}
- }
+ if (Trace)
+ Tracing::scores[Us][PASSED] = apply_weight(score, Weights[PassedPawns]);
- // 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.
+ // Add the scores to the middle game and endgame eval
+ return apply_weight(score, Weights[PassedPawns]);
+ }
- void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo &ei) {
- assert(square_is_ok(s));
- assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
+ // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides, this is quite
+ // conservative and returns a winning score only when we are very sure that the pawn is winning.
- 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);
+ Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
- if ( pos.piece_on(b6) == piece_of_color_and_type(opposite_color(us), PAWN)
- && pos.see(s, b6) < 0
- && pos.see(s, b8) < 0)
+ Bitboard b, b2, blockers, supporters, queeningPath, candidates;
+ Square s, blockSq, queeningSquare;
+ Color c, winnerSide, loserSide;
+ bool pathDefended, opposed;
+ int pliesToGo, movesToGo, oppMovesToGo, sacptg, blockersCount, minKingDist, kingptg, d;
+ int pliesToQueen[] = { 256, 256 };
+
+ // Step 1. Hunt for unstoppable passed pawns. If we find at least one,
+ // record how many plies are required for promotion.
+ for (c = WHITE; c <= BLACK; c++)
{
- ei.mgValue -= Sign[us] * TrappedBishopA7H7Penalty;
- ei.egValue -= Sign[us] * TrappedBishopA7H7Penalty;
- }
- }
+ // Skip if other side has non-pawn pieces
+ if (pos.non_pawn_material(~c))
+ continue;
+
+ b = ei.pi->passed_pawns(c);
+ while (b)
+ {
+ s = pop_lsb(&b);
+ queeningSquare = relative_square(c, file_of(s) | RANK_8);
+ queeningPath = forward_bb(c, s);
- // 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.
+ // Compute plies to queening and check direct advancement
+ movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(c, s) == RANK_2);
+ oppMovesToGo = square_distance(pos.king_square(~c), queeningSquare) - int(c != pos.side_to_move());
+ pathDefended = ((ei.attackedBy[c][ALL_PIECES] & queeningPath) == queeningPath);
- void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei) {
+ if (movesToGo >= oppMovesToGo && !pathDefended)
+ continue;
- Piece pawn = piece_of_color_and_type(us, PAWN);
- Square b2, b3, c3;
+ // Opponent king cannot block because path is defended and position
+ // is not in check. So only friendly pieces can be blockers.
+ assert(!pos.checkers());
+ assert((queeningPath & pos.pieces()) == (queeningPath & pos.pieces(c)));
- assert(Chess960);
- assert(square_is_ok(s));
- assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
+ // Add moves needed to free the path from friendly pieces and retest condition
+ movesToGo += popcount(queeningPath & pos.pieces(c));
- if (square_file(s) == FILE_A)
- {
- b2 = relative_square(us, SQ_B2);
- b3 = relative_square(us, SQ_B3);
- c3 = relative_square(us, SQ_C3);
+ if (movesToGo >= oppMovesToGo && !pathDefended)
+ continue;
+
+ pliesToGo = 2 * movesToGo - int(c == pos.side_to_move());
+ pliesToQueen[c] = std::min(pliesToQueen[c], pliesToGo);
+ }
}
- else
+
+ // Step 2. If either side cannot promote at least three plies before the other side then situation
+ // becomes too complex and we give up. Otherwise we determine the possibly "winning side"
+ if (abs(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3)
+ return SCORE_ZERO;
+
+ winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK);
+ loserSide = ~winnerSide;
+
+ // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
+ b = candidates = pos.pieces(loserSide, PAWN);
+
+ while (b)
{
- b2 = relative_square(us, SQ_G2);
- b3 = relative_square(us, SQ_G3);
- c3 = relative_square(us, SQ_F3);
+ s = pop_lsb(&b);
+
+ // Compute plies from queening
+ queeningSquare = relative_square(loserSide, file_of(s) | RANK_8);
+ movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
+ pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
+
+ // Check if (without even considering any obstacles) we're too far away or doubled
+ if ( pliesToQueen[winnerSide] + 3 <= pliesToGo
+ || (forward_bb(loserSide, s) & pos.pieces(loserSide, PAWN)))
+ candidates ^= s;
}
- if (pos.piece_on(b2) == pawn)
+ // If any candidate is already a passed pawn it _may_ promote in time. We give up.
+ if (candidates & ei.pi->passed_pawns(loserSide))
+ return SCORE_ZERO;
+
+ // Step 4. Check new passed pawn creation through king capturing and pawn sacrifices
+ b = candidates;
+
+ while (b)
{
- Value penalty;
+ s = pop_lsb(&b);
+ sacptg = blockersCount = 0;
+ minKingDist = kingptg = 256;
- if (!pos.square_is_empty(b3))
- penalty = 2*TrappedBishopA1H1Penalty;
- else if (pos.piece_on(c3) == pawn)
- penalty = TrappedBishopA1H1Penalty;
- else
- penalty = TrappedBishopA1H1Penalty / 2;
+ // Compute plies from queening
+ queeningSquare = relative_square(loserSide, file_of(s) | RANK_8);
+ movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
+ pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
+
+ // Generate list of blocking pawns and supporters
+ supporters = adjacent_files_bb(file_of(s)) & candidates;
+ opposed = forward_bb(loserSide, s) & pos.pieces(winnerSide, PAWN);
+ blockers = passed_pawn_mask(loserSide, s) & pos.pieces(winnerSide, PAWN);
+
+ assert(blockers);
+
+ // How many plies does it take to remove all the blocking pawns?
+ while (blockers)
+ {
+ blockSq = pop_lsb(&blockers);
+ movesToGo = 256;
+
+ // Check pawns that can give support to overcome obstacle, for instance
+ // black pawns: a4, b4 white: b2 then pawn in b4 is giving support.
+ if (!opposed)
+ {
+ b2 = supporters & in_front_bb(winnerSide, blockSq + pawn_push(winnerSide));
+
+ while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
+ {
+ d = square_distance(blockSq, pop_lsb(&b2)) - 2;
+ movesToGo = std::min(movesToGo, d);
+ }
+ }
+
+ // Check pawns that can be sacrificed against the blocking pawn
+ b2 = attack_span_mask(winnerSide, blockSq) & candidates & ~(1ULL << s);
+
+ while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
+ {
+ d = square_distance(blockSq, pop_lsb(&b2)) - 2;
+ movesToGo = std::min(movesToGo, d);
+ }
- ei.mgValue -= Sign[us] * penalty;
- ei.egValue -= Sign[us] * penalty;
+ // If obstacle can be destroyed with an immediate pawn exchange / sacrifice,
+ // it's not a real obstacle and we have nothing to add to pliesToGo.
+ if (movesToGo <= 0)
+ continue;
+
+ // Plies needed to sacrifice against all the blocking pawns
+ sacptg += movesToGo * 2;
+ blockersCount++;
+
+ // Plies needed for the king to capture all the blocking pawns
+ d = square_distance(pos.king_square(loserSide), blockSq);
+ minKingDist = std::min(minKingDist, d);
+ kingptg = (minKingDist + blockersCount) * 2;
+ }
+
+ // Check if pawn sacrifice plan _may_ save the day
+ if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg)
+ return SCORE_ZERO;
+
+ // Check if king capture plan _may_ save the day (contains some false positives)
+ if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg)
+ return SCORE_ZERO;
}
+
+ // Winning pawn is unstoppable and will promote as first, return big score
+ Score score = make_score(0, (Value) 1280 - 32 * pliesToQueen[winnerSide]);
+ return winnerSide == WHITE ? score : -score;
}
@@ -1104,107 +1043,135 @@ namespace {
// available for minor pieces on the central four files on ranks 2--4. Safe
// squares one, two or three squares behind a friendly pawn are counted
// twice. Finally, the space bonus is scaled by a weight taken from the
- // material hash table.
- template
- void evaluate_space(const Position& pos, EvalInfo& ei) {
+ // material hash table. The aim is to improve play on game opening.
+ template
+ int evaluate_space(const Position& pos, EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
// Find the safe squares for our pieces inside the area defined by
- // SpaceMask[us]. A square is unsafe if it is attacked by an enemy
+ // SpaceMask[]. A square is unsafe if it is attacked by an enemy
// pawn, or if it is undefended and attacked by an enemy piece.
+ Bitboard safe = SpaceMask[Us]
+ & ~pos.pieces(Us, PAWN)
+ & ~ei.attackedBy[Them][PAWN]
+ & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
- 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(Us, PAWN);
+ behind |= (Us == WHITE ? behind >> 8 : behind << 8);
+ behind |= (Us == WHITE ? behind >> 16 : behind << 16);
- int space = count_1s_max_15(safeSquares)
- + count_1s_max_15(behindFriendlyPawns & safeSquares);
+ // Since SpaceMask[Us] is fully on our half of the board
+ assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);
- ei.mgValue += Sign[Us] * apply_weight(Value(space * ei.mi->space_weight()), WeightSpace);
+ // Count safe + (behind & safe) with a single popcount
+ return popcount((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
}
- // apply_weight() applies an evaluation weight to a value
+ // interpolate() interpolates between a middle game and an endgame score,
+ // based on game phase. It also scales the return value by a ScaleFactor array.
- inline Value apply_weight(Value v, int w) {
- return (v*w) / 0x100;
- }
+ Value interpolate(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);
- // 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.
+ 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));
+ }
- Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]) {
+ // apply_weight() weights score v by score w trying to prevent overflow
+ 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);
+ }
- assert(mv > -VALUE_INFINITE && mv < VALUE_INFINITE);
- assert(ev > -VALUE_INFINITE && ev < VALUE_INFINITE);
- assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
+ // weight_option() computes the value of an evaluation weight, by combining
+ // two UCI-configurable weights (midgame and endgame) with an internal weight.
+
+ Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
- ev = apply_scale_factor(ev, sf[(ev > Value(0) ? WHITE : BLACK)]);
+ // Scale option value from 100 to 256
+ int mg = Options[mgOpt] * 256 / 100;
+ int eg = Options[egOpt] * 256 / 100;
- Value result = Value(int((mv * ph + ev * (128 - ph)) / 128));
- return Value(int(result) & ~(GrainSize - 1));
+ return apply_weight(make_score(mg, eg), internalWeight);
}
- // weight_option() computes the value of an evaluation weight, by combining
- // an UCI-configurable weight with an internal weight.
+ // Tracing functions definitions
+
+ double to_cp(Value v) { return double(v) / double(PawnValueMg); }
- int weight_option(const std::string& opt, int internalWeight) {
+ void Tracing::add(int idx, Score wScore, Score bScore) {
- int uciWeight = get_option_value_int(opt);
- uciWeight = (uciWeight * 0x100) / 100;
- return (uciWeight * internalWeight) / 0x100;
+ scores[WHITE][idx] = wScore;
+ scores[BLACK][idx] = bScore;
}
+ void Tracing::row(const char* name, int idx) {
+
+ Score wScore = scores[WHITE][idx];
+ Score bScore = scores[BLACK][idx];
+
+ switch (idx) {
+ case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL:
+ stream << std::setw(20) << name << " | --- --- | --- --- | "
+ << std::setw(6) << to_cp(mg_value(wScore)) << " "
+ << std::setw(6) << to_cp(eg_value(wScore)) << " \n";
+ break;
+ default:
+ stream << std::setw(20) << name << " | " << std::noshowpos
+ << std::setw(5) << to_cp(mg_value(wScore)) << " "
+ << std::setw(5) << to_cp(eg_value(wScore)) << " | "
+ << std::setw(5) << to_cp(mg_value(bScore)) << " "
+ << std::setw(5) << to_cp(eg_value(bScore)) << " | "
+ << std::showpos
+ << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " "
+ << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n";
+ }
+ }
- // init_safety() initizes the king safety evaluation, based on UCI
- // parameters. It is called from read_weights().
+ std::string Tracing::do_trace(const Position& pos) {
- void init_safety() {
+ Search::RootColor = pos.side_to_move();
- QueenContactCheckBonus = get_option_value_int("Queen 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");
+ stream.str("");
+ stream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
+ memset(scores, 0, 2 * (TOTAL + 1) * sizeof(Score));
- 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");
+ Value margin;
+ do_evaluate(pos, margin);
- 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)));
- }
+ std::string totals = stream.str();
+ stream.str("");
- 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);
+ stream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
+ << " | MG EG | MG EG | MG EG \n"
+ << "---------------------+-------------+-------------+---------------\n";
- if (SafetyTable[i] > Value(peak))
- SafetyTable[i] = Value(peak);
- }
+ row("Material, PST, Tempo", PST);
+ row("Material imbalance", IMBALANCE);
+ row("Pawns", PAWN);
+ row("Knights", KNIGHT);
+ row("Bishops", BISHOP);
+ row("Rooks", ROOK);
+ row("Queens", QUEEN);
+ row("Mobility", MOBILITY);
+ row("King safety", KING);
+ row("Threats", THREAT);
+ row("Passed pawns", PASSED);
+ row("Unstoppable pawns", UNSTOPPABLE);
+ row("Space", SPACE);
+
+ stream << "---------------------+-------------+-------------+---------------\n";
+ row("Total", TOTAL);
+ stream << totals;
+
+ return stream.str();
}
}