/*
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 Tracing {
+
+ enum Term { // First 8 entries are for PieceType
+ MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERM_NB
+ };
+
+ Score scores[COLOR_NB][TERM_NB];
+
+ std::ostream& operator<<(std::ostream& os, Term idx);
+
+ double to_cp(Value v);
+ void write(int idx, Color c, Score s);
+ void write(int idx, Score w, Score b = SCORE_ZERO);
+ std::string do_trace(const Position& pos);
+ }
+
+
// Struct EvalInfo contains various information computed and collected
// by the evaluation functions.
struct EvalInfo {
// kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
// given color which attack a square in the kingRing of the enemy king. The
- // weights of the individual piece types are given by the variables
- // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
- // KnightAttackWeight in evaluate.cpp
+ // weights of the individual piece types are given by the elements in the
+ // KingAttackWeights array.
int kingAttackersWeight[COLOR_NB];
- // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
- // directly adjacent to the king of the given color. Pieces which attack
- // more than one square are counted multiple times. For instance, if black's
- // king is on g8 and there's a white knight on g5, this knight adds
- // 2 to kingAdjacentZoneAttacksCount[BLACK].
+ // kingAdjacentZoneAttacksCount[color] is the number of attacks by the given
+ // color to squares directly adjacent to the enemy king. Pieces which attack
+ // more than one square are counted multiple times. For instance, if there is
+ // a white knight on g5 and black's king is on g8, this white knight adds 2
+ // to kingAdjacentZoneAttacksCount[WHITE].
int kingAdjacentZoneAttacksCount[COLOR_NB];
Bitboard pinnedPieces[COLOR_NB];
};
- namespace Tracing {
- enum Terms { // First 8 entries are for PieceType
- MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERMS_NB
- };
+ // Evaluation weights, indexed by the corresponding evaluation term
+ enum { Mobility, PawnStructure, PassedPawns, Space, KingSafety };
- 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}
+ };
- 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(-68,-49), S(-46,-33), S(-3,-12), S( 5, -4), S( 9, 11), S(15, 16), // Knights
+ S( 23, 27), S( 33, 28), S(37, 29) },
+ { S(-49,-44), S(-23,-16), S(16, 1), S(29, 16), S(40, 25), S(51, 34), // Bishops
+ S( 55, 43), S( 61, 49), S(64, 51), S(68, 52), S(73, 55), S(75, 60),
+ S( 80, 65), S( 86, 66) },
+ { S(-50,-57), S(-28,-22), S(-11, 7), S(-1, 29), S( 0, 39), S( 1, 46), // Rooks
+ S( 10, 66), S( 16, 79), S(22, 86), S(23,103), S(30,109), S(33,111),
+ S( 37,115), S( 38,119), S(48,124) },
+ { S(-43,-30), S(-27,-15), S( 1, -5), S( 2, -3), S(14, 10), S(18, 24), // Queens
+ S( 20, 27), S( 33, 37), S(33, 38), S(34, 43), S(40, 46), S(43, 56),
+ S( 46, 61), S( 52, 63), S(52, 63), S(57, 65), S(60, 70), S(61, 74),
+ S( 67, 80), S( 76, 82), S(77, 88), S(82, 94), S(86, 95), S(90, 96),
+ S( 94, 99), S( 96,100), S(99,111), S(99,112) }
};
- // 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) }
+ // 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(28, 7), S(42,11) }, // Knights
+ { S(12, 3), S(18, 5) } // Bishops
};
// Threat[defended/weak][minor/major attacking][attacked PieceType] contains
// 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)
+ 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) }
};
+ 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);
// 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 RookContactCheck = 71;
+ const int QueenCheck = 50;
+ const int RookCheck = 37;
+ 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));
// Init king safety tables only if we are going to use them
if (pos.non_pawn_material(Us) >= QueenValueMg)
}
- // 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>
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.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);
+ // Bonus for outpost square
+ if ( relative_rank(Us, s) >= RANK_4
+ && !(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s)))
+ score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)];
- // Bishop and knight outpost square
- if (!(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s)))
- score += evaluate_outpost<Pt, Us>(pos, ei, s);
-
- // Bishop or knight behind a pawn
+ // Bonus when behind a pawn
if ( relative_rank(Us, s) < RANK_5
&& (pos.pieces(PAWN) & (s + pawn_push(Us))))
score += MinorBehindPawn;
+
+ // Penalty for pawns on same color square of bishop
+ if (Pt == BISHOP)
+ score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s);
+
+ // An important Chess960 pattern: A cornered bishop blocked by a friendly
+ // pawn diagonally in front of it is a very serious problem, especially
+ // when that pawn is also blocked.
+ if ( Pt == BISHOP
+ && pos.is_chess960()
+ && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
+ {
+ Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
+ if (pos.piece_on(s + d) == make_piece(Us, PAWN))
+ score -= !pos.empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4
+ : pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? TrappedBishopA1H1 * 2
+ : TrappedBishopA1H1;
+ }
}
if (Pt == ROOK)
{
- // Rook 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;
-
- if (mob > 3 || ei.pi->semiopen_file(Us, file_of(s)))
- continue;
-
- Square ksq = pos.king_square(Us);
+ score += ei.pi->semiopen_file(Them, file_of(s)) ? RookOnOpenFile : RookOnSemiOpenFile;
- // 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);
+ // Recursively call evaluate_pieces() of next piece type until KING excluded
return score - evaluate_pieces<NextPt, Them, Trace>(pos, ei, mobility, mobilityArea);
}
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(74, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
+ + 8 * ei.kingAdjacentZoneAttacksCount[Them]
+ + 25 * popcount<Max15>(undefended)
+ + 11 * (ei.pinnedPieces[Us] != 0)
+ - mg_value(score) / 8
+ - !pos.count<QUEEN>(Them) * 60;
// Analyse the enemy's safe queen contact checks. Firstly, find the
- // undefended squares around the king that are attacked by the enemy's
- // queen...
+ // undefended squares around the king reachable by the enemy queen...
b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
if (b)
{
// ...and then remove squares not supported by another enemy piece
- b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
- | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
+ b &= ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
+ | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK];
if (b)
- attackUnits += QueenContactCheck * popcount<Max15>(b);
+ attackUnits += QueenContactCheck * popcount<Max15>(b);
}
// Analyse the enemy's safe rook contact checks. Firstly, find the
- // undefended squares around the king that are attacked by the enemy's
- // rooks...
+ // undefended squares around the king reachable by the enemy rooks...
b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
// Consider only squares where the enemy's rook gives check
{
// ...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]);
+ | ei.attackedBy[Them][BISHOP]);
if (b)
- attackUnits += RookContactCheck * popcount<Max15>(b);
+ attackUnits += RookContactCheck * popcount<Max15>(b);
}
// Analyse the enemy's safe distance checks for sliders and knights
- safe = ~(pos.pieces(Them) | ei.attackedBy[Us][ALL_PIECES]);
+ safe = ~(ei.attackedBy[Us][ALL_PIECES] | pos.pieces(Them));
- b1 = pos.attacks_from<ROOK>(ksq) & safe;
+ b1 = pos.attacks_from<ROOK >(ksq) & safe;
b2 = pos.attacks_from<BISHOP>(ksq) & safe;
// Enemy queen safe checks
if (b)
attackUnits += KnightCheck * popcount<Max15>(b);
- // To index KingDanger[] attackUnits must be in [0, 99] range
- attackUnits = std::min(99, std::max(0, attackUnits));
-
// Finally, extract the king danger score from the KingDanger[]
// array and subtract the score from evaluation.
- score -= KingDanger[attackUnits];
+ score -= KingDanger[std::max(std::min(attackUnits, 399), 0)];
}
if (Trace)
template<Color Us, bool Trace>
Score evaluate_threats(const Position& pos, const EvalInfo& ei) {
- const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Square Up = (Us == WHITE ? DELTA_N : DELTA_S);
+ const Square Left = (Us == WHITE ? DELTA_NW : DELTA_SE);
+ const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW);
+ const Bitboard TRank2BB = (Us == WHITE ? Rank2BB : Rank7BB);
+ const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
enum { Defended, Weak };
enum { Minor, Major };
- Bitboard b, weak, defended;
+ Bitboard b, weak, defended, safeThreats;
Score score = SCORE_ZERO;
- // Non-pawn enemies defended by a pawn and under our attack
- defended = (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 (weak)
+ {
+ b = pos.pieces(Us, PAWN) & ( ~ei.attackedBy[Them][ALL_PIECES]
+ | ei.attackedBy[Us][ALL_PIECES]);
+
+ 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];
// Add a bonus according to the kind of attacking pieces
if (defended)
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 = weak & ei.attackedBy[Us][KING];
if (b)
score += more_than_one(b) ? KingOnMany : KingOnOne;
}
+ // 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()));
+
+ 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 (Trace)
Tracing::write(Tracing::THREAT, Us, score);
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 += distance(pos.king_square(Them), blockSq) * 5 * rr
- - 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 -= 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 (Trace)
- Tracing::write(Tracing::PASSED, Us, apply_weight(score, Weights[PassedPawns]));
+ Tracing::write(Tracing::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);
assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);
// Count safe + (behind & safe) with a single popcount
- return popcount<Full>((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
+ int bonus = popcount<Full>((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
+ int weight = pos.count<KNIGHT>(Us) + pos.count<BISHOP>(Us)
+ + pos.count<KNIGHT>(Them) + pos.count<BISHOP>(Them);
+
+ return make_score(bonus * weight * weight, 0);
}
EvalInfo ei;
Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO };
- Thread* thisThread = pos.this_thread();
// Initialize score by reading the incrementally updated scores included
// in the position object (material + piece square tables).
score = pos.psq_score();
// Probe the material hash table
- ei.mi = Material::probe(pos, thisThread->materialTable, thisThread->endgames);
- score += ei.mi->material_value();
+ ei.mi = Material::probe(pos);
+ score += ei.mi->imbalance();
// If we have a specialized evaluation function for the current material
// configuration, call it and return.
if (ei.mi->specialized_eval_exists())
- return ei.mi->evaluate(pos) + Eval::Tempo;
+ return ei.mi->evaluate(pos);
// Probe the pawn hash table
- ei.pi = Pawns::probe(pos, thisThread->pawnsTable);
- score += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
+ ei.pi = Pawns::probe(pos);
+ score += ei.pi->pawns_score() * Weights[PawnStructure];
// Initialize attack and king safety bitboards
init_eval_info<WHITE>(pos, ei);
ei.attackedBy[WHITE][ALL_PIECES] |= ei.attackedBy[WHITE][KING];
ei.attackedBy[BLACK][ALL_PIECES] |= ei.attackedBy[BLACK][KING];
- // Do not include in mobility squares protected by enemy pawns or occupied by our pawns or king
- Bitboard mobilityArea[] = { ~(ei.attackedBy[BLACK][PAWN] | pos.pieces(WHITE, PAWN, KING)),
- ~(ei.attackedBy[WHITE][PAWN] | pos.pieces(BLACK, PAWN, KING)) };
+ // 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)
+ };
+
+ // 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))
+ };
// Evaluate pieces and mobility
score += evaluate_pieces<KNIGHT, WHITE, Trace>(pos, ei, mobility, mobilityArea);
- score += apply_weight(mobility[WHITE] - mobility[BLACK], Weights[Mobility]);
+ score += (mobility[WHITE] - mobility[BLACK]) * Weights[Mobility];
// Evaluate kings after all other pieces because we need complete attack
// information when computing the king safety evaluation.
// 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);
-
- // 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]);
+ Bitboard b;
+ if ((b = ei.pi->passed_pawns(WHITE)) != 0)
+ score += int(relative_rank(WHITE, frontmost_sq(WHITE, b))) * Unstoppable;
+
+ if ((b = ei.pi->passed_pawns(BLACK)) != 0)
+ score -= int(relative_rank(BLACK, frontmost_sq(BLACK, b))) * Unstoppable;
}
+ // Evaluate space for both sides, only during opening
+ if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= 11756)
+ score += (evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei)) * Weights[Space];
+
// Scale winning side if position is more drawish than it appears
Color strongSide = eg_value(score) > VALUE_DRAW ? WHITE : BLACK;
ScaleFactor sf = ei.mi->scale_factor(pos, strongSide);
// pawns are drawish.
else if ( abs(eg_value(score)) <= BishopValueEg
&& ei.pi->pawn_span(strongSide) <= 1
- && !pos.pawn_passed(~strongSide, pos.king_square(~strongSide)))
+ && !pos.pawn_passed(~strongSide, pos.square<KING>(~strongSide)))
sf = ei.pi->pawn_span(strongSide) ? ScaleFactor(56) : ScaleFactor(38);
}
v /= int(PHASE_MIDGAME);
- // In case of tracing add all single evaluation contributions for both white and black
+ // In case of tracing add all single evaluation terms 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::IMBALANCE, ei.mi->imbalance());
+ Tracing::write(PAWN, ei.pi->pawns_score());
+ Tracing::write(Tracing::MOBILITY, mobility[WHITE] * Weights[Mobility]
+ , mobility[BLACK] * Weights[Mobility]);
+ Tracing::write(Tracing::SPACE, evaluate_space<WHITE>(pos, ei) * Weights[Space]
+ , evaluate_space<BLACK>(pos, ei) * Weights[Space]);
Tracing::write(Tracing::TOTAL, score);
- Tracing::ei = ei;
- Tracing::sf = sf;
}
- return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo;
+ return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo; // Side to move point of view
}
- // Tracing function definitions
+ // Tracing functions
double Tracing::to_cp(Value v) { return double(v) / PawnValueEg; }
void Tracing::write(int idx, Color c, Score s) { scores[c][idx] = s; }
void Tracing::write(int idx, Score w, Score b) {
-
- write(idx, WHITE, w);
- write(idx, BLACK, b);
+ scores[WHITE][idx] = w, scores[BLACK][idx] = b;
}
- 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";
- }
+ std::ostream& Tracing::operator<<(std::ostream& os, Term t) {
+
+ double wScore[] = { to_cp(mg_value(scores[WHITE][t])), to_cp(eg_value(scores[WHITE][t])) };
+ double bScore[] = { to_cp(mg_value(scores[BLACK][t])), to_cp(eg_value(scores[BLACK][t])) };
+
+ if (t == MATERIAL || t == IMBALANCE || t == Term(PAWN) || t == TOTAL)
+ os << " --- --- | --- --- | ";
+ else
+ os << std::setw(5) << wScore[MG] << " " << std::setw(5) << wScore[EG] << " | "
+ << std::setw(5) << bScore[MG] << " " << std::setw(5) << bScore[EG] << " | ";
+
+ os << std::setw(5) << wScore[MG] - bScore[MG] << " "
+ << std::setw(5) << wScore[EG] - bScore[EG] << " \n";
+
+ return os;
}
std::string Tracing::do_trace(const Position& pos) {
ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2)
<< " Eval term | White | Black | Total \n"
<< " | MG EG | MG EG | MG EG \n"
- << "----------------+-------------+-------------+-------------\n";
-
- print(ss, "Material", MATERIAL);
- print(ss, "Imbalance", IMBALANCE);
- print(ss, "Pawns", PAWN);
- print(ss, "Knights", KNIGHT);
- print(ss, "Bishops", BISHOP);
- print(ss, "Rooks", ROOK);
- print(ss, "Queens", QUEEN);
- print(ss, "Mobility", MOBILITY);
- print(ss, "King safety", KING);
- print(ss, "Threats", THREAT);
- print(ss, "Passed pawns", PASSED);
- print(ss, "Space", SPACE);
-
- ss << "----------------+-------------+-------------+-------------\n";
- print(ss, "Total", TOTAL);
+ << "----------------+-------------+-------------+-------------\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);
ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n";
}
- /// init() computes evaluation weights.
+ /// init() computes evaluation weights, usually at startup
void 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)
+ for (int i = 0; i < 400; ++i)
{
- t = int(std::min(Peak, std::min(0.4 * i * i, t + MaxSlope)));
- KingDanger[i] = apply_weight(make_score(t, 0), Weights[KingSafety]);
+ t = std::min(Peak, std::min(i * i * 27, t + MaxSlope));
+ KingDanger[i] = make_score(t / 1000, 0) * Weights[KingSafety];
}
}