/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#include <algorithm>
#include <cassert>
+#include <cstring> // For std::memset
#include <iomanip>
#include <sstream>
#include "evaluate.h"
#include "material.h"
#include "pawns.h"
-#include "thread.h"
namespace {
+ namespace Trace {
+
+ enum Term { // First 8 entries are for PieceType
+ MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERM_NB
+ };
+
+ double scores[TERM_NB][COLOR_NB][PHASE_NB];
+
+ double to_cp(Value v) { return double(v) / PawnValueEg; }
+
+ void add(int idx, Color c, Score s) {
+ scores[idx][c][MG] = to_cp(mg_value(s));
+ scores[idx][c][EG] = to_cp(eg_value(s));
+ }
+
+ void add(int idx, Score w, Score b = SCORE_ZERO) {
+ add(idx, WHITE, w); add(idx, BLACK, b);
+ }
+
+ std::ostream& operator<<(std::ostream& os, Term t) {
+
+ if (t == MATERIAL || t == IMBALANCE || t == Term(PAWN) || t == TOTAL)
+ os << " --- --- | --- --- | ";
+ else
+ os << std::setw(5) << scores[t][WHITE][MG] << " "
+ << std::setw(5) << scores[t][WHITE][EG] << " | "
+ << std::setw(5) << scores[t][BLACK][MG] << " "
+ << std::setw(5) << scores[t][BLACK][EG] << " | ";
+
+ os << std::setw(5) << scores[t][WHITE][MG] - scores[t][BLACK][MG] << " "
+ << std::setw(5) << scores[t][WHITE][EG] - scores[t][BLACK][EG] << " \n";
+
+ return os;
+ }
+ }
+
+ using namespace Trace;
+
// 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.
+ // attacked by a given color and piece type (can be also ALL_PIECES).
Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB];
// kingRing[color] is the zone around the king which is considered
// kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
// given color which attack a square in the kingRing of the enemy king. The
- // weights of the individual piece types are given by the variables
- // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
- // KnightAttackWeight in evaluate.cpp
+ // weights of the individual piece types are given by the elements in the
+ // KingAttackWeights array.
int kingAttackersWeight[COLOR_NB];
- // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
- // directly adjacent to the king of the given color. Pieces which attack
- // more than one square are counted multiple times. For instance, if black's
- // king is on g8 and there's a white knight on g5, this knight adds
- // 2 to kingAdjacentZoneAttacksCount[BLACK].
+ // kingAdjacentZoneAttacksCount[color] is the number of attacks by the given
+ // color to squares directly adjacent to the enemy king. Pieces which attack
+ // more than one square are counted multiple times. For instance, if there is
+ // a white knight on g5 and black's king is on g8, this white knight adds 2
+ // to kingAdjacentZoneAttacksCount[WHITE].
int kingAdjacentZoneAttacksCount[COLOR_NB];
Bitboard pinnedPieces[COLOR_NB];
+ Pawns::Entry* pi;
};
- namespace Tracing {
- enum Terms { // First 8 entries are for PieceType
- MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERMS_NB
- };
+ // Evaluation weights, indexed by the corresponding evaluation term
+ enum { Mobility, PawnStructure, PassedPawns, Space, KingSafety, Threats };
- Score scores[COLOR_NB][TERMS_NB];
- EvalInfo ei;
- ScaleFactor sf;
+ const struct Weight { int mg, eg; } Weights[] = {
+ {289, 344}, {233, 201}, {221, 273}, {46, 0}, {322, 0}, {350, 256}
+ };
- double to_cp(Value v);
- void write(int idx, Color c, Score s);
- void write(int idx, Score w, Score b = SCORE_ZERO);
- void print(std::stringstream& ss, const char* name, int idx);
- std::string do_trace(const Position& pos);
+ Score operator*(Score s, const Weight& w) {
+ return make_score(mg_value(s) * w.mg / 256, eg_value(s) * w.eg / 256);
}
- // Evaluation weights, indexed by evaluation term
- enum { Mobility, PawnStructure, PassedPawns, Space, KingSafety };
- const struct Weight { int mg, eg; } Weights[] = {
- {289, 344}, {233, 201}, {221, 273}, {46, 0}, {318, 0}
- };
- typedef Value V;
+ #define V(v) Value(v)
#define S(mg, eg) make_score(mg, eg)
// MobilityBonus[PieceType][attacked] contains bonuses for middle and end
// friendly pieces.
const Score MobilityBonus[][32] = {
{}, {},
- { S(-65,-50), S(-42,-30), S(-9,-10), S( 3, 0), S(15, 10), S(27, 20), // Knights
- S( 37, 28), S( 42, 31), S(44, 33) },
- { S(-52,-47), S(-28,-23), S( 6, 1), S(20, 15), S(34, 29), S(48, 43), // Bishops
- S( 60, 55), S( 68, 63), S(74, 68), S(77, 72), S(80, 75), S(82, 77),
- S( 84, 79), S( 86, 81) },
- { S(-47,-53), S(-31,-26), S(-5, 0), S( 1, 16), S( 7, 32), S(13, 48), // Rooks
- S( 18, 64), S( 22, 80), S(26, 96), S(29,109), S(31,115), S(33,119),
- S( 35,122), S( 36,123), S(37,124) },
- { S(-42,-40), S(-28,-23), S(-5, -7), S( 0, 0), S( 6, 10), S(11, 19), // Queens
- S( 13, 29), S( 18, 38), S(20, 40), S(21, 41), S(22, 41), S(22, 41),
- S( 22, 41), S( 23, 41), S(24, 41), S(25, 41), S(25, 41), S(25, 41),
- S( 25, 41), S( 25, 41), S(25, 41), S(25, 41), S(25, 41), S(25, 41),
- S( 25, 41), S( 25, 41), S(25, 41), S(25, 41) }
+ { S(-70,-52), S(-52,-37), S( -7,-17), S( 0, -6), S( 8, 5), S( 16, 9), // Knights
+ S( 23, 20), S( 31, 21), S( 36, 22) },
+ { S(-49,-44), S(-22,-13), S( 16, 0), S( 27, 11), S( 38, 19), S( 52, 34), // Bishops
+ S( 56, 44), S( 65, 47), S( 67, 51), S( 73, 56), S( 81, 59), S( 83, 69),
+ S( 95, 72), S(100, 75) },
+ { S(-49,-57), S(-22,-14), S(-10, 18), S( -5, 39), S( -4, 50), S( -2, 58), // Rooks
+ S( 6, 78), S( 11, 86), S( 17, 92), S( 19,103), S( 26,111), S( 27,115),
+ S( 36,119), S( 41,121), S( 50,122) },
+ { S(-41,-24), S(-26, -8), S( 0, 6), S( 2, 14), S( 12, 27), S( 21, 40), // Queens
+ S( 22, 45), S( 37, 55), S( 40, 57), S( 43, 63), S( 50, 68), S( 52, 74),
+ S( 56, 80), S( 66, 84), S( 68, 85), S( 69, 88), S( 71, 92), S( 72, 94),
+ S( 80, 96), S( 89, 98), S( 94,101), S(102,113), S(106,114), S(107,116),
+ S(112,125), S(113,127), S(117,137), S(122,143) }
};
- // Outpost[PieceType][Square] contains bonuses for knights and bishops outposts,
- // 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), // 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) }
+ // Mask of allowed outpost squares indexed by color
+ const Bitboard OutpostMask[COLOR_NB] = {
+ Rank4BB | Rank5BB | Rank6BB, Rank5BB | Rank4BB | Rank3BB
+ };
+
+ // Outpost[knight/bishop][supported by pawn] contains bonuses for knights and
+ // bishops outposts, bigger if outpost piece is supported by a pawn.
+ const Score Outpost[][2] = {
+ { S(42,11), S(63,17) }, // Knights
+ { S(18, 5), S(27, 8) } // Bishops
};
- // Threat[attacking][attacked] contains bonuses according to which piece
- // type attacks which one.
- const Score Threat[][PIECE_TYPE_NB] = {
- { S(0, 0), S( 0, 0), S(19, 37), S(24, 37), S(44, 97), S(35,106) }, // Protected Minor attacks
- { S(0, 0), S( 0, 0), S( 9, 14), S( 9, 14), S( 7, 14), S(24, 48) }, // Protected Major attacks
- { S(0, 0), S( 0,32), S(33, 41), S(31, 50), S(41,100), S(35,104) }, // Weak Minor attacks
- { S(0, 0), S( 0,27), S(26, 57), S(26, 57), S(0 , 43), S(23, 51) } // Weak Major attacks
+ // ReachableOutpost[knight/bishop][supported by pawn] contains bonuses for knights and
+ // bishops which can reach a outpost square in one move, bigger if outpost square is supported by a pawn.
+ const Score ReachableOutpost[][2] = {
+ { S(21, 5), S(31, 8) }, // Knights
+ { S( 8, 2), S(13, 4) } // Bishops
+ };
+
+ // Threat[minor/rook][attacked PieceType] contains
+ // bonuses according to which piece type attacks which one.
+ // Attacks on lesser pieces which are pawn defended are not considered.
+ const Score Threat[2][PIECE_TYPE_NB] = {
+ { S(0, 0), S(0, 32), S(25, 39), S(28, 44), S(42, 98), S(35,105) }, // Minor attacks
+ { S(0, 0), S(0, 27), S(26, 57), S(26, 57), S( 0, 30), S(23, 51) } // Rook attacks
};
// 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(87, 118), S(84, 122), S(114, 203), S(121, 217)
+ // type is attacked by a pawn.
+ const Score ThreatenedByPawn[PIECE_TYPE_NB] = {
+ S(0, 0), S(0, 0), S(107, 138), S(84, 122), S(114, 203), S(121, 217)
};
+ // Passed[mg/eg][rank] contains midgame and endgame bonuses for passed pawns.
+ // We don't use a Score because we process the two components independently.
+ const Value Passed[][RANK_NB] = {
+ { V(0), V( 1), V(34), V(90), V(214), V(328) },
+ { V(7), V(14), V(37), V(63), V(134), V(189) }
+ };
+
+ // PassedFile[File] contains a bonus according to the file of a passed pawn.
+ const Score PassedFile[] = {
+ S( 12, 10), S( 3, 10), S( 1, -8), S(-27, -12),
+ S(-27, -12), S( 1, -8), S( 3, 10), S( 12, 10)
+ };
+
+ const Score ThreatenedByHangingPawn = S(40, 60);
+
// Assorted bonuses and penalties used by evaluation
- const Score KingOnOne = S(2 , 58);
- const Score KingOnMany = S(6 ,125);
- const Score RookOnPawn = S(7 , 27);
- const Score RookOpenFile = S(43, 21);
- const Score RookSemiOpenFile = S(19, 10);
- const Score BishopPawns = S( 8, 12);
- const Score MinorBehindPawn = S(16, 0);
- const Score TrappedRook = S(92, 0);
- const Score Unstoppable = S( 0, 20);
- const Score Hanging = S(31, 26);
+ const Score KingOnOne = S( 2, 58);
+ const Score KingOnMany = S( 6,125);
+ const Score RookOnPawn = S( 7, 27);
+ const Score RookOnOpenFile = S(43, 21);
+ const Score RookOnSemiOpenFile = S(19, 10);
+ const Score BishopPawns = S( 8, 12);
+ const Score MinorBehindPawn = S(16, 0);
+ const Score TrappedRook = S(92, 0);
+ const Score Unstoppable = S( 0, 20);
+ const Score Hanging = S(31, 26);
+ const Score PawnAttackThreat = S(20, 20);
+ const Score Checked = S(20, 20);
// 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
const Score TrappedBishopA1H1 = S(50, 50);
#undef S
+ #undef V
// SpaceMask[Color] contains the area of the board which is considered
// by the space evaluation. In the middlegame, each side is given a bonus
// based on how many squares inside this area are safe and available for
// friendly minor pieces.
- const Bitboard SpaceMask[] = {
+ const Bitboard SpaceMask[COLOR_NB] = {
(FileCBB | FileDBB | FileEBB | FileFBB) & (Rank2BB | Rank3BB | Rank4BB),
(FileCBB | FileDBB | FileEBB | FileFBB) & (Rank7BB | Rank6BB | Rank5BB)
};
- // King danger constants and variables. The king danger scores are taken
- // from KingDanger[]. Various little "meta-bonuses" measuring the strength
+ // King danger constants and variables. The king danger scores are looked-up
+ // in KingDanger[]. Various little "meta-bonuses" measuring the strength
// of the enemy attack are added up into an integer, which is used as an
// index to KingDanger[].
- //
+ Score KingDanger[512];
+
// 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 QueenContactCheck = 24;
- const int RookContactCheck = 16;
- const int QueenCheck = 12;
- const int RookCheck = 8;
- const int BishopCheck = 2;
- const int KnightCheck = 3;
-
- // KingDanger[attackUnits] contains the actual king danger weighted
- // scores, indexed by a calculated integer number.
- Score KingDanger[128];
-
- // apply_weight() weighs score 'v' by weight 'w' trying to prevent overflow
- Score apply_weight(Score v, const Weight& w) {
- return make_score(mg_value(v) * w.mg / 256, eg_value(v) * w.eg / 256);
- }
+ const int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 7, 5, 4, 1 };
+
+ // Penalties for enemy's safe checks
+ const int QueenContactCheck = 89;
+ const int QueenCheck = 50;
+ const int RookCheck = 45;
+ const int BishopCheck = 6;
+ const int KnightCheck = 14;
// init_eval_info() initializes king bitboards for given color adding
template<Color Us>
void init_eval_info(const Position& pos, EvalInfo& ei) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
const Square Down = (Us == WHITE ? DELTA_S : DELTA_N);
ei.pinnedPieces[Us] = pos.pinned_pieces(Us);
-
- Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
- ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
+ Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.square<KING>(Them));
+ ei.attackedBy[Them][ALL_PIECES] |= b;
+ ei.attackedBy[Us][ALL_PIECES] |= ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
// Init king safety tables only if we are going to use them
- if (pos.non_pawn_material(Us) > QueenValueMg + PawnValueMg)
+ if (pos.non_pawn_material(Us) >= QueenValueMg)
{
ei.kingRing[Them] = b | shift_bb<Down>(b);
b &= ei.attackedBy[Us][PAWN];
}
- // evaluate_outpost() evaluates bishop and knight outpost squares
-
- template<PieceType Pt, Color Us>
- Score evaluate_outpost(const Position& pos, const EvalInfo& ei, Square s) {
-
- const Color Them = (Us == WHITE ? BLACK : WHITE);
-
- assert (Pt == BISHOP || Pt == KNIGHT);
-
- // Initial bonus based on square
- Value bonus = Outpost[Pt == BISHOP][relative_square(Us, s)];
-
- // Increase bonus if supported by pawn, especially if the opponent has
- // no minor piece which can trade with the outpost piece.
- if (bonus && (ei.attackedBy[Us][PAWN] & s))
- {
- if ( !pos.pieces(Them, KNIGHT)
- && !(squares_of_color(s) & pos.pieces(Them, BISHOP)))
- bonus += bonus + bonus / 2;
- else
- bonus += bonus / 2;
- }
-
- return make_score(bonus * 2, bonus / 2);
- }
-
-
// evaluate_pieces() assigns bonuses and penalties to the pieces of a given color
- template<PieceType Pt, Color Us, bool Trace>
- Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, Bitboard* mobilityArea) {
+ template<PieceType Pt, Color Us, bool DoTrace>
+ Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, const Bitboard* mobilityArea) {
- Bitboard b;
+ Bitboard b, bb;
Square s;
Score score = SCORE_ZERO;
const PieceType NextPt = (Us == WHITE ? Pt : PieceType(Pt + 1));
const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Square* pl = pos.
list<Pt>(Us);
+ const Square* pl = pos.
squares<Pt>(Us);
ei.attackedBy[Us][Pt] = 0;
: pos.attacks_from<Pt>(s);
if (ei.pinnedPieces[Us] & s)
- b &= LineBB[pos.king_square(Us)][s];
+ b &= LineBB[pos.square<KING>(Us)][s];
ei.attackedBy[Us][ALL_PIECES] |= ei.attackedBy[Us][Pt] |= b;
{
ei.kingAttackersCount[Us]++;
ei.kingAttackersWeight[Us] += KingAttackWeights[Pt];
- Bitboard bb = b & ei.attackedBy[Them][KING];
+ bb = b & ei.attackedBy[Them][KING];
if (bb)
ei.kingAdjacentZoneAttacksCount[Us] += popcount<Max15>(bb);
}
| ei.attackedBy[Them][BISHOP]
| ei.attackedBy[Them][ROOK]);
- int mob = Pt != QUEEN ? popcount<Max15>(b & mobilityArea[Us])
- : popcount<Full >(b & mobilityArea[Us]);
+ int mob = popcount<Pt == QUEEN ? Full : Max15>(b & mobilityArea[Us]);
mobility[Us] += MobilityBonus[Pt][mob];
- // Decrease score if we are attacked by an enemy pawn. The remaining part
- // of threat evaluation must be done later when we have full attack info.
- if (ei.attackedBy[Them][PAWN] & s)
- score -= ThreatenedByPawn[Pt];
-
if (Pt == BISHOP || Pt == KNIGHT)
{
- // Penalty for bishop with same colored pawns
- if (Pt == BISHOP)
- score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s);
-
- // Bishop and knight outpost square
- if (!(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s)))
- score += evaluate_outpost<Pt, Us>(pos, ei, s);
+ // Bonus for outpost squares
+ bb = OutpostMask[Us] & ~ei.pi->pawn_attacks_span(Them);
+ if (bb & s)
+ score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)];
+ else
+ {
+ bb &= b & ~pos.pieces(Us);
+ if (bb)
+ score += ReachableOutpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & bb)];
+ }
- // Bishop or knight behind a pawn
+ // Bonus when behind a pawn
if ( relative_rank(Us, s) < RANK_5
&& (pos.pieces(PAWN) & (s + pawn_push(Us))))
score += MinorBehindPawn;
+
+ // Penalty for pawns on same color square of bishop
+ if (Pt == BISHOP)
+ score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s);
+
+ // An important Chess960 pattern: A cornered bishop blocked by a friendly
+ // pawn diagonally in front of it is a very serious problem, especially
+ // when that pawn is also blocked.
+ if ( Pt == BISHOP
+ && pos.is_chess960()
+ && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
+ {
+ Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
+ if (pos.piece_on(s + d) == make_piece(Us, PAWN))
+ score -= !pos.empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4
+ : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? TrappedBishopA1H1 * 2
+ : TrappedBishopA1H1;
+ }
}
if (Pt == ROOK)
{
- // Rook piece attacking enemy pawns on the same rank/file
+ // Bonus for aligning with enemy pawns on the same rank/file
if (relative_rank(Us, s) >= RANK_5)
{
- Bitboard pawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s];
- if (pawns)
- score += popcount<Max15>(pawns) * RookOnPawn;
+ Bitboard alignedPawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s];
+ if (alignedPawns)
+ score += popcount<Max15>(alignedPawns) * RookOnPawn;
}
- // Give a bonus for a rook on a open or semi-open file
+ // Bonus when on an open or semi-open file
if (ei.pi->semiopen_file(Us, file_of(s)))
- score += ei.pi->semiopen_file(Them, file_of(s)) ? RookOpenFile : RookSemiOpenFile;
+ score += ei.pi->semiopen_file(Them, file_of(s)) ? RookOnOpenFile : RookOnSemiOpenFile;
- if (mob > 3 || ei.pi->semiopen_file(Us, file_of(s)))
- continue;
-
- Square ksq = pos.king_square(Us);
-
- // Penalize rooks which are trapped by a king. Penalize more if the
- // king has lost its castling capability.
- if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
- && (rank_of(ksq) == rank_of(s) || relative_rank(Us, ksq) == RANK_1)
- && !ei.pi->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq)))
- score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us));
- }
+ // Penalize when trapped by the king, even more if king cannot castle
+ if (mob <= 3 && !ei.pi->semiopen_file(Us, file_of(s)))
+ {
+ Square ksq = pos.square<KING>(Us);
- // An important Chess960 pattern: A cornered bishop blocked by a friendly
- // pawn diagonally in front of it is a very serious problem, especially
- // when that pawn is also blocked.
- if ( Pt == BISHOP
- && pos.is_chess960()
- && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
- {
- Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
- if (pos.piece_on(s + d) == make_piece(Us, PAWN))
- score -= !pos.empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4
- : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? TrappedBishopA1H1 * 2
- : TrappedBishopA1H1;
+ if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
+ && (rank_of(ksq) == rank_of(s) || relative_rank(Us, ksq) == RANK_1)
+ && !ei.pi->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq)))
+ score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us));
+ }
}
}
- if (Trace)
- Tracing::write(Pt, Us, score);
+ if (DoTrace)
+ Trace::add(Pt, Us, score);
- return score - evaluate_pieces<NextPt, Them, Trace>(pos, ei, mobility, mobilityArea);
+ // Recursively call evaluate_pieces() of next piece type until KING excluded
+ return score - evaluate_pieces<NextPt, Them, DoTrace>(pos, ei, mobility, mobilityArea);
}
template<>
- Score evaluate_pieces<KING, WHITE, false>(const Position&, EvalInfo&, Score*, Bitboard*) { return SCORE_ZERO; }
+ Score evaluate_pieces<KING, WHITE, false>(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; }
template<>
- Score evaluate_pieces<KING, WHITE, true>(const Position&, EvalInfo&, Score*, Bitboard*) { return SCORE_ZERO; }
+ Score evaluate_pieces<KING, WHITE, true>(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; }
// evaluate_king() assigns bonuses and penalties to a king of a given color
- template<Color Us, bool Trace>
+ template<Color Us, bool DoTrace>
Score evaluate_king(const Position& pos, const EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
Bitboard undefended, b, b1, b2, safe;
int attackUnits;
- const Square ksq = pos.king_square(Us);
+ const Square ksq = pos.square<KING>(Us);
// King shelter and enemy pawns storm
Score score = ei.pi->king_safety<Us>(pos, ksq);
| ei.attackedBy[Us][QUEEN]);
// Initialize the 'attackUnits' variable, which is used later on as an
- // index to the KingDanger[] array. The initial value is based on the
+ // index into the KingDanger[] array. The initial value is based on the
// number and types of the enemy's attacking pieces, the number of
// attacked and undefended squares around our king and the quality of
// the pawn shelter (current 'score' value).
- attackUnits = std::min(20, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
- + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount<Max15>(undefended))
- + 2 * (ei.pinnedPieces[Us] != 0)
- - mg_value(score) / 32
- - !pos.count<QUEEN>(Them) * 15;
+ attackUnits = std::min(72, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
+ + 9 * ei.kingAdjacentZoneAttacksCount[Them]
+ + 27 * popcount<Max15>(undefended)
+ + 11 * !!ei.pinnedPieces[Us]
+ - 64 * !pos.count<QUEEN>(Them)
+ - mg_value(score) / 8;
// Analyse the enemy's safe queen contact checks. Firstly, find the
- // undefended squares around the king that are attacked by the enemy's
- // queen...
+ // undefended squares around the king reachable by the enemy queen...
b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
if (b)
{
// ...and then remove squares not supported by another enemy piece
- b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
- | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
+ b &= ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
+ | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]
+ | ei.attackedBy[Them][KING];
if (b)
- attackUnits += QueenContactCheck * popcount<Max15>(b);
- }
-
- // Analyse the enemy's safe rook contact checks. Firstly, find the
- // undefended squares around the king that are attacked by the enemy's
- // rooks...
- b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
-
- // Consider only squares where the enemy's rook gives check
- b &= PseudoAttacks[ROOK][ksq];
-
- if (b)
- {
- // ...and then remove squares not supported by another enemy piece
- b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
- | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]);
-
- if (b)
- attackUnits += RookContactCheck * popcount<Max15>(b);
+ attackUnits += QueenContactCheck * popcount<Max15>(b);
}
// Analyse the enemy's safe distance checks for sliders and knights
- safe = ~(pos.pieces(Them) | ei.attackedBy[Us][ALL_PIECES]);
+ safe = ~(ei.attackedBy[Us][ALL_PIECES] | pos.pieces(Them));
- b1 = pos.attacks_from<ROOK>(ksq) & safe;
+ b1 = pos.attacks_from<ROOK >(ksq) & safe;
b2 = pos.attacks_from<BISHOP>(ksq) & safe;
// Enemy queen safe checks
b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
if (b)
+ {
attackUnits += QueenCheck * popcount<Max15>(b);
+ score -= Checked;
+ }
// Enemy rooks safe checks
b = b1 & ei.attackedBy[Them][ROOK];
if (b)
+ {
attackUnits += RookCheck * popcount<Max15>(b);
+ score -= Checked;
+ }
// Enemy bishops safe checks
b = b2 & ei.attackedBy[Them][BISHOP];
if (b)
+ {
attackUnits += BishopCheck * popcount<Max15>(b);
+ score -= Checked;
+ }
// Enemy knights safe checks
b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
if (b)
+ {
attackUnits += KnightCheck * popcount<Max15>(b);
-
- // To index KingDanger[] attackUnits must be in [0, 99] range
- attackUnits = std::min(99, std::max(0, attackUnits));
+ score -= Checked;
+ }
// Finally, extract the king danger score from the KingDanger[]
// array and subtract the score from evaluation.
- score -= KingDanger[attackUnits];
+ score -= KingDanger[std::max(std::min(attackUnits, 399), 0)];
}
- if (Trace)
- Tracing::write(KING, Us, score);
+ if (DoTrace)
+ Trace::add(KING, Us, score);
return score;
}
-
-
// evaluate_threats() assigns bonuses according to the type of attacking piece
// and the type of attacked one.
- template<Color Us, bool Trace>
+ template<Color Us, bool DoTrace>
Score evaluate_threats(const Position& pos, const EvalInfo& ei) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Square Up = (Us == WHITE ? DELTA_N : DELTA_S);
+ const Square Left = (Us == WHITE ? DELTA_NW : DELTA_SE);
+ const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW);
+ const Bitboard TRank2BB = (Us == WHITE ? Rank2BB : Rank7BB);
+ const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
+
+ enum { Minor, Rook };
- enum { Protected_Minor, Protected_Major, Minor, Major };
- Bitboard b, weakEnemies, protectedEnemies;
+ Bitboard b, weak, defended, safeThreats;
Score score = SCORE_ZERO;
- // Enemies defended by a pawn and under our attack
- protectedEnemies = (pos.pieces(Them) ^ pos.pieces(Them, PAWN))
- & ei.attackedBy[Them][PAWN]
- & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]);
+ // Non-pawn enemies attacked by a pawn
+ weak = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Us][PAWN];
- if (protectedEnemies)
+ if (weak)
{
- // Enemies defended by a pawn and under our attack by a minor piece
- b = protectedEnemies & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
- while (b)
- score += Threat[Protected_Minor][type_of(pos.piece_on(pop_lsb(&b)))];
+ b = pos.pieces(Us, PAWN) & ( ~ei.attackedBy[Them][ALL_PIECES]
+ | ei.attackedBy[Us][ALL_PIECES]);
- // Enemies defended by a pawn and under our attack by a ROOK
- b = protectedEnemies & (ei.attackedBy[Us][ROOK]);
- while (b)
- score += Threat[Protected_Major][type_of(pos.piece_on(pop_lsb(&b)))];
+ safeThreats = (shift_bb<Right>(b) | shift_bb<Left>(b)) & weak;
+
+ if (weak ^ safeThreats)
+ score += ThreatenedByHangingPawn;
+
+ while (safeThreats)
+ score += ThreatenedByPawn[type_of(pos.piece_on(pop_lsb(&safeThreats)))];
}
+ // Non-pawn enemies defended by a pawn
+ defended = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Them][PAWN];
+
// Enemies not defended by a pawn and under our attack
- weakEnemies = pos.pieces(Them)
- & ~ei.attackedBy[Them][PAWN]
- & ei.attackedBy[Us][ALL_PIECES];
+ weak = pos.pieces(Them)
+ & ~ei.attackedBy[Them][PAWN]
+ & ei.attackedBy[Us][ALL_PIECES];
- // Add a bonus according if the attacking pieces are minor or major
- if (weakEnemies)
+ // Add a bonus according to the kind of attacking pieces
+ if (defended | weak)
{
- b = weakEnemies & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
+ b = (defended | weak) & (ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP]);
while (b)
score += Threat[Minor][type_of(pos.piece_on(pop_lsb(&b)))];
- b = weakEnemies & (ei.attackedBy[Us][ROOK] | ei.attackedBy[Us][QUEEN]);
+ b = (pos.pieces(Them, QUEEN) | weak) & ei.attackedBy[Us][ROOK];
while (b)
- score += Threat[Major][type_of(pos.piece_on(pop_lsb(&b)))];
+ score += Threat[Rook ][type_of(pos.piece_on(pop_lsb(&b)))];
- b = weakEnemies & ~ei.attackedBy[Them][ALL_PIECES];
+ b = weak & ~ei.attackedBy[Them][ALL_PIECES];
if (b)
- score += more_than_one(b) ? Hanging * popcount<Max15>(b) : Hanging;
+ score += Hanging * popcount<Max15>(b);
- b = weakEnemies & ei.attackedBy[Us][KING];
+ b = weak & ei.attackedBy[Us][KING];
if (b)
score += more_than_one(b) ? KingOnMany : KingOnOne;
}
- if (Trace)
- Tracing::write(Tracing::THREAT, Us, score);
+ // Bonus if some pawns can safely push and attack an enemy piece
+ b = pos.pieces(Us, PAWN) & ~TRank7BB;
+ b = shift_bb<Up>(b | (shift_bb<Up>(b & TRank2BB) & ~pos.pieces()));
- return score;
+ b &= ~pos.pieces()
+ & ~ei.attackedBy[Them][PAWN]
+ & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
+
+ b = (shift_bb<Left>(b) | shift_bb<Right>(b))
+ & pos.pieces(Them)
+ & ~ei.attackedBy[Us][PAWN];
+
+ if (b)
+ score += popcount<Max15>(b) * PawnAttackThreat;
+
+ if (DoTrace)
+ Trace::add(THREAT, Us, score * Weights[Threats]);
+
+ return score * Weights[Threats];
}
// evaluate_passed_pawns() evaluates the passed pawns of the given color
- template<Color Us, bool Trace>
+ template<Color Us, bool DoTrace>
Score evaluate_passed_pawns(const Position& pos, const EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
int r = relative_rank(Us, s) - RANK_2;
int rr = r * (r - 1);
- // Base bonus based on rank
- Value mbonus = Value(17 * rr), ebonus = Value(7 * (rr + r + 1));
+ Value mbonus = Passed[MG][r], ebonus = Passed[EG][r];
if (rr)
{
Square blockSq = s + pawn_push(Us);
// Adjust bonus based on the king's proximity
- ebonus += square_distance(pos.king_square(Them), blockSq) * 5 * rr
- - square_distance(pos.king_square(Us ), blockSq) * 2 * rr;
+ ebonus += distance(pos.square<KING>(Them), blockSq) * 5 * rr
+ - distance(pos.square<KING>(Us ), blockSq) * 2 * rr;
// If blockSq is not the queening square then consider also a second push
if (relative_rank(Us, blockSq) != RANK_8)
- ebonus -= square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr;
+ ebonus -= distance(pos.square<KING>(Us), blockSq + pawn_push(Us)) * rr;
// If the pawn is free to advance, then increase the bonus
if (pos.empty(blockSq))
// If there aren't any enemy attacks, assign a big bonus. Otherwise
// assign a smaller bonus if the block square isn't attacked.
- int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 0;
+ int k = !unsafeSquares ? 18 : !(unsafeSquares & blockSq) ? 8 : 0;
// If the path to queen is fully defended, assign a big bonus.
// Otherwise assign a smaller bonus if the block square is defended.
if (pos.count<PAWN>(Us) < pos.count<PAWN>(Them))
ebonus += ebonus / 4;
- score += make_score(mbonus, ebonus);
+ score += make_score(mbonus, ebonus) + PassedFile[file_of(s)];
}
- if (Trace)
- Tracing::write(Tracing::PASSED, Us, apply_weight(score, Weights[PassedPawns]));
+ if (DoTrace)
+ Trace::add(PASSED, Us, score * Weights[PassedPawns]);
// Add the scores to the middlegame and endgame eval
- return apply_weight(score, Weights[PassedPawns]);
- }
-
-
- // evaluate_unstoppable_pawns() scores the most advanced passed pawn. In case
- // both players have no pieces but pawns, this is somewhat related to the
- // possibility that pawns are unstoppable.
-
- Score evaluate_unstoppable_pawns(Color us, const EvalInfo& ei) {
-
- Bitboard b = ei.pi->passed_pawns(us);
-
- return b ? Unstoppable * int(relative_rank(us, frontmost_sq(us, b))) : SCORE_ZERO;
+ return score * Weights[PassedPawns];
}
// space evaluation is a simple bonus based on the number of safe squares
// available for minor pieces on the central four files on ranks 2--4. Safe
// squares one, two or three squares behind a friendly pawn are counted
- // twice. Finally, the space bonus is scaled by a weight taken from the
- // material hash table. The aim is to improve play on game opening.
+ // twice. Finally, the space bonus is multiplied by a weight. The aim is to
+ // improve play on game opening.
template<Color Us>
- int evaluate_space(const Position& pos, const EvalInfo& ei) {
+ Score evaluate_space(const Position& pos, const EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
behind |= (Us == WHITE ? behind >> 8 : behind << 8);
behind |= (Us == WHITE ? behind >> 16 : behind << 16);
- // Since SpaceMask[Us] is fully on our half of the board
+ // Since SpaceMask[Us] is fully on our half of the board...
assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);
- // Count safe + (behind & safe) with a single popcount
- return popcount<Full>((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
- }
-
+ // ...count safe + (behind & safe) with a single popcount
+ int bonus = popcount<Full>((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
+ int weight = pos.count<KNIGHT>(Us) + pos.count<BISHOP>(Us)
+ + pos.count<KNIGHT>(Them) + pos.count<BISHOP>(Them);
- // do_evaluate() is the evaluation entry point, called directly from evaluate()
+ return make_score(bonus * weight * weight, 0);
+ }
- template<bool Trace>
- Value do_evaluate(const Position& pos) {
- assert(!pos.checkers());
+ // evaluate_initiative() computes the initiative correction value for the
+ // position, i.e. second order bonus/malus based on the known attacking/defending
+ // status of the players.
+ Score evaluate_initiative(const Position& pos, int asymmetry, Value eg) {
- EvalInfo ei;
- Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO };
- Thread* thisThread = pos.this_thread();
+ int kingDistance = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
+ int pawns = pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK);
- // Initialize score by reading the incrementally updated scores included
- // in the position object (material + piece square tables).
- // Score is computed from the point of view of white.
- score = pos.psq_score();
+ // Compute the initiative bonus for the attacking side
+ int initiative = 8 * (pawns + asymmetry + kingDistance - 15);
- // Probe the material hash table
- ei.mi = Material::probe(pos, thisThread->materialTable, thisThread->endgames);
- score += ei.mi->material_value();
+ // Now apply the bonus: note that we find the attacking side by extracting
+ // the sign of the endgame value, and that we carefully cap the bonus so
+ // that the endgame score will never be divided by more than two.
+ int value = ((eg > 0) - (eg < 0)) * std::max(initiative, -abs(eg / 2));
- // 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) + Eval::Tempo;
+ return make_score(0, value);
+ }
- // Probe the pawn hash table
- ei.pi = Pawns::probe(pos, thisThread->pawnsTable);
- score += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
+} // namespace
- // Initialize attack and king safety bitboards
- init_eval_info<WHITE>(pos, ei);
- init_eval_info<BLACK>(pos, ei);
- ei.attackedBy[WHITE][ALL_PIECES] |= ei.attackedBy[WHITE][KING];
- ei.attackedBy[BLACK][ALL_PIECES] |= ei.attackedBy[BLACK][KING];
+/// evaluate() is the main evaluation function. It returns a static evaluation
+/// of the position always from the point of view of the side to move.
- // Do not include in mobility squares protected by enemy pawns or occupied by our pawns or king
- Bitboard mobilityArea[] = { ~(ei.attackedBy[BLACK][PAWN] | pos.pieces(WHITE, PAWN, KING)),
- ~(ei.attackedBy[WHITE][PAWN] | pos.pieces(BLACK, PAWN, KING)) };
+template<bool DoTrace>
+Value Eval::evaluate(const Position& pos) {
- // Evaluate pieces and mobility
- score += evaluate_pieces<KNIGHT, WHITE, Trace>(pos, ei, mobility, mobilityArea);
- score += apply_weight(mobility[WHITE] - mobility[BLACK], Weights[Mobility]);
+ assert(!pos.checkers());
- // Evaluate kings after all other pieces because we need complete attack
- // information when computing the king safety evaluation.
- score += evaluate_king<WHITE, Trace>(pos, ei)
- - evaluate_king<BLACK, Trace>(pos, ei);
+ EvalInfo ei;
+ Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO };
- // Evaluate tactical threats, we need full attack information including king
- score += evaluate_threats<WHITE, Trace>(pos, ei)
- - evaluate_threats<BLACK, Trace>(pos, ei);
+ // Initialize score by reading the incrementally updated scores included
+ // in the position object (material + piece square tables).
+ // Score is computed from the point of view of white.
+ score = pos.psq_score();
- // Evaluate passed pawns, we need full attack information including king
- score += evaluate_passed_pawns<WHITE, Trace>(pos, ei)
- - evaluate_passed_pawns<BLACK, Trace>(pos, ei);
+ // Probe the material hash table
+ Material::Entry* me = Material::probe(pos);
+ score += me->imbalance();
- // If both sides have only pawns, score for potential unstoppable pawns
- if (!pos.non_pawn_material(WHITE) && !pos.non_pawn_material(BLACK))
- score += evaluate_unstoppable_pawns(WHITE, ei)
- - evaluate_unstoppable_pawns(BLACK, ei);
+ // If we have a specialized evaluation function for the current material
+ // configuration, call it and return.
+ if (me->specialized_eval_exists())
+ return me->evaluate(pos);
- // Evaluate space for both sides, only in middlegame
- if (ei.mi->space_weight())
- {
- int s = evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei);
- score += apply_weight(s * ei.mi->space_weight(), Weights[Space]);
- }
+ // Probe the pawn hash table
+ ei.pi = Pawns::probe(pos);
+ score += ei.pi->pawns_score() * Weights[PawnStructure];
- // Scale winning side if position is more drawish than it appears
- Color strongSide = eg_value(score) > VALUE_DRAW ? WHITE : BLACK;
- ScaleFactor sf = ei.mi->scale_factor(pos, strongSide);
+ // Initialize attack and king safety bitboards
+ ei.attackedBy[WHITE][ALL_PIECES] = ei.attackedBy[BLACK][ALL_PIECES] = 0;
+ init_eval_info<WHITE>(pos, ei);
+ init_eval_info<BLACK>(pos, ei);
- // If we don't already have an unusual scale factor, check for certain
- // types of endgames, and use a lower scale for those.
- if ( ei.mi->game_phase() < PHASE_MIDGAME
- && (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN))
- {
- if (pos.opposite_bishops())
- {
- // Endgame with opposite-colored bishops and no other pieces (ignoring pawns)
- // is almost a draw, in case of KBP vs KB is even more a draw.
- if ( pos.non_pawn_material(WHITE) == BishopValueMg
- && pos.non_pawn_material(BLACK) == BishopValueMg)
- sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(32) : ScaleFactor(8);
-
- // Endgame with opposite-colored bishops, but also other pieces. Still
- // a bit drawish, but not as drawish as with only the two bishops.
- else
- sf = ScaleFactor(50 * sf / SCALE_FACTOR_NORMAL);
- }
- // Endings where weaker side can place his king in front of the opponent's
- // pawns are drawish.
- else if ( abs(eg_value(score)) <= BishopValueEg
- && ei.pi->pawn_span(strongSide) <= 1
- && !pos.pawn_passed(~strongSide, pos.king_square(~strongSide)))
- sf = ei.pi->pawn_span(strongSide) ? ScaleFactor(56) : ScaleFactor(38);
- }
+ // Pawns blocked or on ranks 2 and 3. Will be excluded from the mobility area
+ Bitboard blockedPawns[] = {
+ pos.pieces(WHITE, PAWN) & (shift_bb<DELTA_S>(pos.pieces()) | Rank2BB | Rank3BB),
+ pos.pieces(BLACK, PAWN) & (shift_bb<DELTA_N>(pos.pieces()) | Rank7BB | Rank6BB)
+ };
- // Interpolate between a middlegame and a (scaled by 'sf') endgame score
- Value v = mg_value(score) * int(ei.mi->game_phase())
- + eg_value(score) * int(PHASE_MIDGAME - ei.mi->game_phase()) * sf / SCALE_FACTOR_NORMAL;
+ // Do not include in mobility squares protected by enemy pawns, or occupied
+ // by our blocked pawns or king.
+ Bitboard mobilityArea[] = {
+ ~(ei.attackedBy[BLACK][PAWN] | blockedPawns[WHITE] | pos.square<KING>(WHITE)),
+ ~(ei.attackedBy[WHITE][PAWN] | blockedPawns[BLACK] | pos.square<KING>(BLACK))
+ };
- v /= int(PHASE_MIDGAME);
+ // Evaluate pieces and mobility
+ score += evaluate_pieces<KNIGHT, WHITE, DoTrace>(pos, ei, mobility, mobilityArea);
+ score += (mobility[WHITE] - mobility[BLACK]) * Weights[Mobility];
- // In case of tracing add all single evaluation contributions for both white and black
- if (Trace)
- {
- Tracing::write(Tracing::MATERIAL, pos.psq_score());
- Tracing::write(Tracing::IMBALANCE, ei.mi->material_value());
- Tracing::write(PAWN, ei.pi->pawns_value());
- Tracing::write(Tracing::MOBILITY, apply_weight(mobility[WHITE], Weights[Mobility])
- , apply_weight(mobility[BLACK], Weights[Mobility]));
- Score w = ei.mi->space_weight() * evaluate_space<WHITE>(pos, ei);
- Score b = ei.mi->space_weight() * evaluate_space<BLACK>(pos, ei);
- Tracing::write(Tracing::SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
- Tracing::write(Tracing::TOTAL, score);
- Tracing::ei = ei;
- Tracing::sf = sf;
- }
+ // Evaluate kings after all other pieces because we need complete attack
+ // information when computing the king safety evaluation.
+ score += evaluate_king<WHITE, DoTrace>(pos, ei)
+ - evaluate_king<BLACK, DoTrace>(pos, ei);
- return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo;
- }
+ // Evaluate tactical threats, we need full attack information including king
+ score += evaluate_threats<WHITE, DoTrace>(pos, ei)
+ - evaluate_threats<BLACK, DoTrace>(pos, ei);
+ // Evaluate passed pawns, we need full attack information including king
+ score += evaluate_passed_pawns<WHITE, DoTrace>(pos, ei)
+ - evaluate_passed_pawns<BLACK, DoTrace>(pos, ei);
- // Tracing function definitions
+ // If both sides have only pawns, score for potential unstoppable pawns
+ if (!pos.non_pawn_material(WHITE) && !pos.non_pawn_material(BLACK))
+ {
+ Bitboard b;
+ if ((b = ei.pi->passed_pawns(WHITE)) != 0)
+ score += int(relative_rank(WHITE, frontmost_sq(WHITE, b))) * Unstoppable;
- double Tracing::to_cp(Value v) { return double(v) / PawnValueEg; }
+ if ((b = ei.pi->passed_pawns(BLACK)) != 0)
+ score -= int(relative_rank(BLACK, frontmost_sq(BLACK, b))) * Unstoppable;
+ }
- void Tracing::write(int idx, Color c, Score s) { scores[c][idx] = s; }
+ // Evaluate space for both sides, only during opening
+ if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= 12222)
+ score += (evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei)) * Weights[Space];
- void Tracing::write(int idx, Score w, Score b) {
+ // Evaluate position potential for the winning side
+ score += evaluate_initiative(pos, ei.pi->pawn_asymmetry(), eg_value(score));
- write(idx, WHITE, w);
- write(idx, BLACK, b);
- }
+ // Scale winning side if position is more drawish than it appears
+ Color strongSide = eg_value(score) > VALUE_DRAW ? WHITE : BLACK;
+ ScaleFactor sf = me->scale_factor(pos, strongSide);
- void Tracing::print(std::stringstream& ss, const char* name, int idx) {
-
- Score wScore = scores[WHITE][idx];
- Score bScore = scores[BLACK][idx];
-
- switch (idx) {
- case MATERIAL: case IMBALANCE: case PAWN: case TOTAL:
- ss << std::setw(15) << name << " | --- --- | --- --- | "
- << std::setw(5) << to_cp(mg_value(wScore - bScore)) << " "
- << std::setw(5) << to_cp(eg_value(wScore - bScore)) << " \n";
- break;
- default:
- ss << std::setw(15) << name << " | " << std::noshowpos
- << std::setw(5) << to_cp(mg_value(wScore)) << " "
- << std::setw(5) << to_cp(eg_value(wScore)) << " | "
- << std::setw(5) << to_cp(mg_value(bScore)) << " "
- << std::setw(5) << to_cp(eg_value(bScore)) << " | "
- << std::setw(5) << to_cp(mg_value(wScore - bScore)) << " "
- << std::setw(5) << to_cp(eg_value(wScore - bScore)) << " \n";
- }
+ // If we don't already have an unusual scale factor, check for certain
+ // types of endgames, and use a lower scale for those.
+ if ( me->game_phase() < PHASE_MIDGAME
+ && (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN))
+ {
+ if (pos.opposite_bishops())
+ {
+ // Endgame with opposite-colored bishops and no other pieces (ignoring pawns)
+ // is almost a draw, in case of KBP vs KB is even more a draw.
+ if ( pos.non_pawn_material(WHITE) == BishopValueMg
+ && pos.non_pawn_material(BLACK) == BishopValueMg)
+ sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(31) : ScaleFactor(9);
+
+ // Endgame with opposite-colored bishops, but also other pieces. Still
+ // a bit drawish, but not as drawish as with only the two bishops.
+ else
+ sf = ScaleFactor(46 * sf / SCALE_FACTOR_NORMAL);
+ }
+ // Endings where weaker side can place his king in front of the opponent's
+ // pawns are drawish.
+ else if ( abs(eg_value(score)) <= BishopValueEg
+ && ei.pi->pawn_span(strongSide) <= 1
+ && !pos.pawn_passed(~strongSide, pos.square<KING>(~strongSide)))
+ sf = ei.pi->pawn_span(strongSide) ? ScaleFactor(51) : ScaleFactor(37);
}
- std::string Tracing::do_trace(const Position& pos) {
+ // Interpolate between a middlegame and a (scaled by 'sf') endgame score
+ Value v = mg_value(score) * int(me->game_phase())
+ + eg_value(score) * int(PHASE_MIDGAME - me->game_phase()) * sf / SCALE_FACTOR_NORMAL;
- std::memset(scores, 0, sizeof(scores));
+ v /= int(PHASE_MIDGAME);
- Value v = do_evaluate<true>(pos);
- v = pos.side_to_move() == WHITE ? v : -v; // White's point of view
+ // In case of tracing add all single evaluation terms
+ if (DoTrace)
+ {
+ Trace::add(MATERIAL, pos.psq_score());
+ Trace::add(IMBALANCE, me->imbalance());
+ Trace::add(PAWN, ei.pi->pawns_score());
+ Trace::add(MOBILITY, mobility[WHITE] * Weights[Mobility]
+ , mobility[BLACK] * Weights[Mobility]);
+ Trace::add(SPACE, evaluate_space<WHITE>(pos, ei) * Weights[Space]
+ , evaluate_space<BLACK>(pos, ei) * Weights[Space]);
+ Trace::add(TOTAL, score);
+ }
- std::stringstream ss;
- ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2)
- << " Eval term | White | Black | Total \n"
- << " | MG EG | MG EG | MG EG \n"
- << "----------------+-------------+-------------+-------------\n";
+ return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo; // Side to move point of view
+}
- print(ss, "Material", MATERIAL);
- print(ss, "Imbalance", IMBALANCE);
- print(ss, "Pawns", PAWN);
- print(ss, "Knights", KNIGHT);
- print(ss, "Bishops", BISHOP);
- print(ss, "Rooks", ROOK);
- print(ss, "Queens", QUEEN);
- print(ss, "Mobility", MOBILITY);
- print(ss, "King safety", KING);
- print(ss, "Threats", THREAT);
- print(ss, "Passed pawns", PASSED);
- print(ss, "Space", SPACE);
+// Explicit template instantiations
+template Value Eval::evaluate<true >(const Position&);
+template Value Eval::evaluate<false>(const Position&);
- ss << "----------------+-------------+-------------+-------------\n";
- print(ss, "Total", TOTAL);
- ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n";
+/// trace() is like evaluate(), but instead of returning a value, it returns
+/// a string (suitable for outputting to stdout) that contains the detailed
+/// descriptions and values of each evaluation term. Useful for debugging.
- return ss.str();
- }
+std::string Eval::trace(const Position& pos) {
-} // namespace
+ std::memset(scores, 0, sizeof(scores));
+ Value v = evaluate<true>(pos);
+ v = pos.side_to_move() == WHITE ? v : -v; // White's point of view
-namespace Eval {
+ std::stringstream ss;
+ ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2)
+ << " Eval term | White | Black | Total \n"
+ << " | MG EG | MG EG | MG EG \n"
+ << "----------------+-------------+-------------+-------------\n"
+ << " Material | " << Term(MATERIAL)
+ << " Imbalance | " << Term(IMBALANCE)
+ << " Pawns | " << Term(PAWN)
+ << " Knights | " << Term(KNIGHT)
+ << " Bishop | " << Term(BISHOP)
+ << " Rooks | " << Term(ROOK)
+ << " Queens | " << Term(QUEEN)
+ << " Mobility | " << Term(MOBILITY)
+ << " King safety | " << Term(KING)
+ << " Threats | " << Term(THREAT)
+ << " Passed pawns | " << Term(PASSED)
+ << " Space | " << Term(SPACE)
+ << "----------------+-------------+-------------+-------------\n"
+ << " Total | " << Term(TOTAL);
- /// evaluate() is the main evaluation function. It returns a static evaluation
- /// of the position always from the point of view of the side to move.
+ ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n";
- Value evaluate(const Position& pos) {
- return do_evaluate<false>(pos);
- }
-
-
- /// trace() is like evaluate(), but instead of returning a value, it returns
- /// a string (suitable for outputting to stdout) that contains the detailed
- /// descriptions and values of each evaluation term. It's mainly used for
- /// debugging.
- std::string trace(const Position& pos) {
- return Tracing::do_trace(pos);
- }
+ return ss.str();
+}
- /// init() computes evaluation weights.
+/// init() computes evaluation weights, usually at startup
- void init() {
+void Eval::init() {
- const double MaxSlope = 30;
- const double Peak = 1280;
+ const int MaxSlope = 8700;
+ const int Peak = 1280000;
+ int t = 0;
- for (int t = 0, i = 1; i < 100; ++i)
- {
- t = int(std::min(Peak, std::min(0.4 * i * i, t + MaxSlope)));
- KingDanger[i] = apply_weight(make_score(t, 0), Weights[KingSafety]);
- }
+ for (int i = 0; i < 400; ++i)
+ {
+ t = std::min(Peak, std::min(i * i * 27, t + MaxSlope));
+ KingDanger[i] = make_score(t / 1000, 0) * Weights[KingSafety];
}
-
-} // namespace Eval
+}
projects / stockfish / blobdiff