mirror of
https://github.com/sockspls/badfish
synced 2025-04-30 08:43:09 +00:00
eb4a124b88
This patch makes it dependant on the count of passed pawns of the strong side instead of 22/64 in every case. passed STC https://tests.stockfishchess.org/tests/view/5ead60966ffeed51f6e32591 LLR: 2.96 (-2.94,2.94) {-0.50,1.50} Total: 50336 W: 9473 L: 9241 D: 31622 Ptnml(0-2): 570, 5371, 13098, 5515, 614 passed LTC https://tests.stockfishchess.org/tests/view/5ead6d3b6ffeed51f6e325b0 LLR: 2.94 (-2.94,2.94) {0.25,1.75} Total: 21952 W: 2810 L: 2603 D: 16539 Ptnml(0-2): 101, 1791, 7005, 1958, 121 closes https://github.com/official-stockfish/Stockfish/pull/2658 bench 4247490
910 lines
34 KiB
C++
910 lines
34 KiB
C++
/*
|
|
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
|
|
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
|
|
Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
|
|
Copyright (C) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, 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
|
|
the Free Software Foundation, either version 3 of the License, or
|
|
(at your option) any later version.
|
|
|
|
Stockfish is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include <algorithm>
|
|
#include <cassert>
|
|
#include <cstring> // For std::memset
|
|
#include <iomanip>
|
|
#include <sstream>
|
|
|
|
#include "bitboard.h"
|
|
#include "evaluate.h"
|
|
#include "material.h"
|
|
#include "pawns.h"
|
|
#include "thread.h"
|
|
|
|
namespace Trace {
|
|
|
|
enum Tracing { NO_TRACE, TRACE };
|
|
|
|
enum Term { // The first 8 entries are reserved for PieceType
|
|
MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, INITIATIVE, TOTAL, TERM_NB
|
|
};
|
|
|
|
Score scores[TERM_NB][COLOR_NB];
|
|
|
|
double to_cp(Value v) { return double(v) / PawnValueEg; }
|
|
|
|
void add(int idx, Color c, Score s) {
|
|
scores[idx][c] = s;
|
|
}
|
|
|
|
void add(int idx, Score w, Score b = SCORE_ZERO) {
|
|
scores[idx][WHITE] = w;
|
|
scores[idx][BLACK] = b;
|
|
}
|
|
|
|
std::ostream& operator<<(std::ostream& os, Score s) {
|
|
os << std::setw(5) << to_cp(mg_value(s)) << " "
|
|
<< std::setw(5) << to_cp(eg_value(s));
|
|
return os;
|
|
}
|
|
|
|
std::ostream& operator<<(std::ostream& os, Term t) {
|
|
|
|
if (t == MATERIAL || t == IMBALANCE || t == INITIATIVE || t == TOTAL)
|
|
os << " ---- ----" << " | " << " ---- ----";
|
|
else
|
|
os << scores[t][WHITE] << " | " << scores[t][BLACK];
|
|
|
|
os << " | " << scores[t][WHITE] - scores[t][BLACK] << "\n";
|
|
return os;
|
|
}
|
|
}
|
|
|
|
using namespace Trace;
|
|
|
|
namespace {
|
|
|
|
// Threshold for lazy and space evaluation
|
|
constexpr Value LazyThreshold = Value(1400);
|
|
constexpr Value SpaceThreshold = Value(12222);
|
|
|
|
// KingAttackWeights[PieceType] contains king attack weights by piece type
|
|
constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 81, 52, 44, 10 };
|
|
|
|
// Penalties for enemy's safe checks
|
|
constexpr int QueenSafeCheck = 772;
|
|
constexpr int RookSafeCheck = 1084;
|
|
constexpr int BishopSafeCheck = 645;
|
|
constexpr int KnightSafeCheck = 792;
|
|
|
|
#define S(mg, eg) make_score(mg, eg)
|
|
|
|
// MobilityBonus[PieceType-2][attacked] contains bonuses for middle and end game,
|
|
// indexed by piece type and number of attacked squares in the mobility area.
|
|
constexpr Score MobilityBonus[][32] = {
|
|
{ S(-62,-81), S(-53,-56), S(-12,-30), S( -4,-14), S( 3, 8), S( 13, 15), // Knight
|
|
S( 22, 23), S( 28, 27), S( 33, 33) },
|
|
{ S(-48,-59), S(-20,-23), S( 16, -3), S( 26, 13), S( 38, 24), S( 51, 42), // Bishop
|
|
S( 55, 54), S( 63, 57), S( 63, 65), S( 68, 73), S( 81, 78), S( 81, 86),
|
|
S( 91, 88), S( 98, 97) },
|
|
{ S(-60,-78), S(-20,-17), S( 2, 23), S( 3, 39), S( 3, 70), S( 11, 99), // Rook
|
|
S( 22,103), S( 31,121), S( 40,134), S( 40,139), S( 41,158), S( 48,164),
|
|
S( 57,168), S( 57,169), S( 62,172) },
|
|
{ S(-34,-36), S(-15,-21), S(-10, -1), S(-10, 22), S( 20, 41), S( 23, 56), // Queen
|
|
S( 23, 59), S( 35, 75), S( 38, 78), S( 53, 96), S( 64, 96), S( 65,100),
|
|
S( 65,121), S( 66,127), S( 67,131), S( 67,133), S( 72,136), S( 72,141),
|
|
S( 77,147), S( 79,150), S( 93,151), S(108,168), S(108,168), S(108,171),
|
|
S(110,182), S(114,182), S(114,192), S(116,219) }
|
|
};
|
|
|
|
// RookOnFile[semiopen/open] contains bonuses for each rook when there is
|
|
// no (friendly) pawn on the rook file.
|
|
constexpr Score RookOnFile[] = { S(19, 7), S(48, 29) };
|
|
|
|
// ThreatByMinor/ByRook[attacked PieceType] contains bonuses according to
|
|
// which piece type attacks which one. Attacks on lesser pieces which are
|
|
// pawn-defended are not considered.
|
|
constexpr Score ThreatByMinor[PIECE_TYPE_NB] = {
|
|
S(0, 0), S(5, 32), S(57, 41), S(77, 56), S(88, 119), S(79, 161)
|
|
};
|
|
|
|
constexpr Score ThreatByRook[PIECE_TYPE_NB] = {
|
|
S(0, 0), S(3, 46), S(37, 68), S(42, 60), S(0, 38), S(58, 41)
|
|
};
|
|
|
|
// PassedRank[Rank] contains a bonus according to the rank of a passed pawn
|
|
constexpr Score PassedRank[RANK_NB] = {
|
|
S(0, 0), S(10, 28), S(17, 33), S(15, 41), S(62, 72), S(168, 177), S(276, 260)
|
|
};
|
|
|
|
// Assorted bonuses and penalties
|
|
constexpr Score BishopPawns = S( 3, 7);
|
|
constexpr Score CorneredBishop = S( 50, 50);
|
|
constexpr Score FlankAttacks = S( 8, 0);
|
|
constexpr Score Hanging = S( 69, 36);
|
|
constexpr Score BishopKingProtector = S( 6, 9);
|
|
constexpr Score KnightKingProtector = S( 8, 9);
|
|
constexpr Score KnightOnQueen = S( 16, 11);
|
|
constexpr Score LongDiagonalBishop = S( 45, 0);
|
|
constexpr Score MinorBehindPawn = S( 18, 3);
|
|
constexpr Score KnightOutpost = S( 56, 36);
|
|
constexpr Score BishopOutpost = S( 30, 23);
|
|
constexpr Score ReachableOutpost = S( 31, 22);
|
|
constexpr Score PassedFile = S( 11, 8);
|
|
constexpr Score PawnlessFlank = S( 17, 95);
|
|
constexpr Score RestrictedPiece = S( 7, 7);
|
|
constexpr Score RookOnQueenFile = S( 5, 9);
|
|
constexpr Score SliderOnQueen = S( 59, 18);
|
|
constexpr Score ThreatByKing = S( 24, 89);
|
|
constexpr Score ThreatByPawnPush = S( 48, 39);
|
|
constexpr Score ThreatBySafePawn = S(173, 94);
|
|
constexpr Score TrappedRook = S( 55, 13);
|
|
constexpr Score WeakQueen = S( 51, 14);
|
|
constexpr Score WeakQueenProtection = S( 15, 0);
|
|
|
|
#undef S
|
|
|
|
// Evaluation class computes and stores attacks tables and other working data
|
|
template<Tracing T>
|
|
class Evaluation {
|
|
|
|
public:
|
|
Evaluation() = delete;
|
|
explicit Evaluation(const Position& p) : pos(p) {}
|
|
Evaluation& operator=(const Evaluation&) = delete;
|
|
Value value();
|
|
|
|
private:
|
|
template<Color Us> void initialize();
|
|
template<Color Us, PieceType Pt> Score pieces();
|
|
template<Color Us> Score king() const;
|
|
template<Color Us> Score threats() const;
|
|
template<Color Us> Score passed() const;
|
|
template<Color Us> Score space() const;
|
|
ScaleFactor scale_factor(Value eg) const;
|
|
Score initiative(Score score) const;
|
|
|
|
const Position& pos;
|
|
Material::Entry* me;
|
|
Pawns::Entry* pe;
|
|
Bitboard mobilityArea[COLOR_NB];
|
|
Score mobility[COLOR_NB] = { SCORE_ZERO, SCORE_ZERO };
|
|
|
|
// attackedBy[color][piece type] is a bitboard representing all squares
|
|
// attacked by a given color and piece type. Special "piece types" which
|
|
// is also calculated is ALL_PIECES.
|
|
Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB];
|
|
|
|
// attackedBy2[color] are the squares attacked by at least 2 units of a given
|
|
// color, including x-rays. But diagonal x-rays through pawns are not computed.
|
|
Bitboard attackedBy2[COLOR_NB];
|
|
|
|
// kingRing[color] are the squares adjacent to the king plus some other
|
|
// very near squares, depending on king position.
|
|
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 "weights" 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 elements in
|
|
// the KingAttackWeights array.
|
|
int kingAttackersWeight[COLOR_NB];
|
|
|
|
// kingAttacksCount[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 kingAttacksCount[WHITE].
|
|
int kingAttacksCount[COLOR_NB];
|
|
};
|
|
|
|
|
|
// Evaluation::initialize() computes king and pawn attacks, and the king ring
|
|
// bitboard for a given color. This is done at the beginning of the evaluation.
|
|
template<Tracing T> template<Color Us>
|
|
void Evaluation<T>::initialize() {
|
|
|
|
constexpr Color Them = ~Us;
|
|
constexpr Direction Up = pawn_push(Us);
|
|
constexpr Direction Down = -Up;
|
|
constexpr Bitboard LowRanks = (Us == WHITE ? Rank2BB | Rank3BB : Rank7BB | Rank6BB);
|
|
|
|
const Square ksq = pos.square<KING>(Us);
|
|
|
|
Bitboard dblAttackByPawn = pawn_double_attacks_bb<Us>(pos.pieces(Us, PAWN));
|
|
|
|
// Find our pawns that are blocked or on the first two ranks
|
|
Bitboard b = pos.pieces(Us, PAWN) & (shift<Down>(pos.pieces()) | LowRanks);
|
|
|
|
// Squares occupied by those pawns, by our king or queen, by blockers to attacks on our king
|
|
// or controlled by enemy pawns are excluded from the mobility area.
|
|
mobilityArea[Us] = ~(b | pos.pieces(Us, KING, QUEEN) | pos.blockers_for_king(Us) | pe->pawn_attacks(Them));
|
|
|
|
// Initialize attackedBy[] for king and pawns
|
|
attackedBy[Us][KING] = pos.attacks_from<KING>(ksq);
|
|
attackedBy[Us][PAWN] = pe->pawn_attacks(Us);
|
|
attackedBy[Us][ALL_PIECES] = attackedBy[Us][KING] | attackedBy[Us][PAWN];
|
|
attackedBy2[Us] = dblAttackByPawn | (attackedBy[Us][KING] & attackedBy[Us][PAWN]);
|
|
|
|
// Init our king safety tables
|
|
Square s = make_square(Utility::clamp(file_of(ksq), FILE_B, FILE_G),
|
|
Utility::clamp(rank_of(ksq), RANK_2, RANK_7));
|
|
kingRing[Us] = PseudoAttacks[KING][s] | s;
|
|
|
|
kingAttackersCount[Them] = popcount(kingRing[Us] & pe->pawn_attacks(Them));
|
|
kingAttacksCount[Them] = kingAttackersWeight[Them] = 0;
|
|
|
|
// Remove from kingRing[] the squares defended by two pawns
|
|
kingRing[Us] &= ~dblAttackByPawn;
|
|
}
|
|
|
|
|
|
// Evaluation::pieces() scores pieces of a given color and type
|
|
template<Tracing T> template<Color Us, PieceType Pt>
|
|
Score Evaluation<T>::pieces() {
|
|
|
|
constexpr Color Them = ~Us;
|
|
constexpr Direction Down = -pawn_push(Us);
|
|
constexpr Bitboard OutpostRanks = (Us == WHITE ? Rank4BB | Rank5BB | Rank6BB
|
|
: Rank5BB | Rank4BB | Rank3BB);
|
|
const Square* pl = pos.squares<Pt>(Us);
|
|
|
|
Bitboard b, bb;
|
|
Score score = SCORE_ZERO;
|
|
|
|
attackedBy[Us][Pt] = 0;
|
|
|
|
for (Square s = *pl; s != SQ_NONE; s = *++pl)
|
|
{
|
|
// Find attacked squares, including x-ray attacks for bishops and rooks
|
|
b = Pt == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(QUEEN))
|
|
: Pt == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(QUEEN) ^ pos.pieces(Us, ROOK))
|
|
: pos.attacks_from<Pt>(s);
|
|
|
|
if (pos.blockers_for_king(Us) & s)
|
|
b &= LineBB[pos.square<KING>(Us)][s];
|
|
|
|
attackedBy2[Us] |= attackedBy[Us][ALL_PIECES] & b;
|
|
attackedBy[Us][Pt] |= b;
|
|
attackedBy[Us][ALL_PIECES] |= b;
|
|
|
|
if (b & kingRing[Them])
|
|
{
|
|
kingAttackersCount[Us]++;
|
|
kingAttackersWeight[Us] += KingAttackWeights[Pt];
|
|
kingAttacksCount[Us] += popcount(b & attackedBy[Them][KING]);
|
|
}
|
|
|
|
int mob = popcount(b & mobilityArea[Us]);
|
|
|
|
mobility[Us] += MobilityBonus[Pt - 2][mob];
|
|
|
|
if (Pt == BISHOP || Pt == KNIGHT)
|
|
{
|
|
// Bonus if piece is on an outpost square or can reach one
|
|
bb = OutpostRanks & attackedBy[Us][PAWN] & ~pe->pawn_attacks_span(Them);
|
|
if (bb & s)
|
|
score += (Pt == KNIGHT) ? KnightOutpost : BishopOutpost;
|
|
else if (Pt == KNIGHT && bb & b & ~pos.pieces(Us))
|
|
score += ReachableOutpost;
|
|
|
|
// Bonus for a knight or bishop shielded by pawn
|
|
if (shift<Down>(pos.pieces(PAWN)) & s)
|
|
score += MinorBehindPawn;
|
|
|
|
// Penalty if the piece is far from the king
|
|
score -= (Pt == KNIGHT ? KnightKingProtector
|
|
: BishopKingProtector) * distance(pos.square<KING>(Us), s);
|
|
|
|
if (Pt == BISHOP)
|
|
{
|
|
// Penalty according to number of pawns on the same color square as the
|
|
// bishop, bigger when the center files are blocked with pawns and smaller
|
|
// when the bishop is outside the pawn chain.
|
|
Bitboard blocked = pos.pieces(Us, PAWN) & shift<Down>(pos.pieces());
|
|
|
|
score -= BishopPawns * pos.pawns_on_same_color_squares(Us, s)
|
|
* (!(attackedBy[Us][PAWN] & s) + popcount(blocked & CenterFiles));
|
|
|
|
// Bonus for bishop on a long diagonal which can "see" both center squares
|
|
if (more_than_one(attacks_bb<BISHOP>(s, pos.pieces(PAWN)) & Center))
|
|
score += LongDiagonalBishop;
|
|
|
|
// 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 ( pos.is_chess960()
|
|
&& (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
|
|
{
|
|
Direction d = pawn_push(Us) + (file_of(s) == FILE_A ? EAST : WEST);
|
|
if (pos.piece_on(s + d) == make_piece(Us, PAWN))
|
|
score -= !pos.empty(s + d + pawn_push(Us)) ? CorneredBishop * 4
|
|
: pos.piece_on(s + d + d) == make_piece(Us, PAWN) ? CorneredBishop * 2
|
|
: CorneredBishop;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (Pt == ROOK)
|
|
{
|
|
// Bonus for rook on the same file as a queen
|
|
if (file_bb(s) & pos.pieces(QUEEN))
|
|
score += RookOnQueenFile;
|
|
|
|
// Bonus for rook on an open or semi-open file
|
|
if (pos.is_on_semiopen_file(Us, s))
|
|
score += RookOnFile[pos.is_on_semiopen_file(Them, s)];
|
|
|
|
// Penalty when trapped by the king, even more if the king cannot castle
|
|
else if (mob <= 3)
|
|
{
|
|
File kf = file_of(pos.square<KING>(Us));
|
|
if ((kf < FILE_E) == (file_of(s) < kf))
|
|
score -= TrappedRook * (1 + !pos.castling_rights(Us));
|
|
}
|
|
}
|
|
|
|
if (Pt == QUEEN)
|
|
{
|
|
// Penalty if any relative pin or discovered attack against the queen
|
|
Bitboard queenPinners;
|
|
if (pos.slider_blockers(pos.pieces(Them, ROOK, BISHOP), s, queenPinners))
|
|
score -= WeakQueen;
|
|
}
|
|
}
|
|
if (T)
|
|
Trace::add(Pt, Us, score);
|
|
|
|
return score;
|
|
}
|
|
|
|
|
|
// Evaluation::king() assigns bonuses and penalties to a king of a given color
|
|
template<Tracing T> template<Color Us>
|
|
Score Evaluation<T>::king() const {
|
|
|
|
constexpr Color Them = ~Us;
|
|
constexpr Bitboard Camp = (Us == WHITE ? AllSquares ^ Rank6BB ^ Rank7BB ^ Rank8BB
|
|
: AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB);
|
|
|
|
Bitboard weak, b1, b2, b3, safe, unsafeChecks = 0;
|
|
Bitboard rookChecks, queenChecks, bishopChecks, knightChecks;
|
|
int kingDanger = 0;
|
|
const Square ksq = pos.square<KING>(Us);
|
|
|
|
// Init the score with king shelter and enemy pawns storm
|
|
Score score = pe->king_safety<Us>(pos);
|
|
|
|
// Attacked squares defended at most once by our queen or king
|
|
weak = attackedBy[Them][ALL_PIECES]
|
|
& ~attackedBy2[Us]
|
|
& (~attackedBy[Us][ALL_PIECES] | attackedBy[Us][KING] | attackedBy[Us][QUEEN]);
|
|
|
|
// Analyse the safe enemy's checks which are possible on next move
|
|
safe = ~pos.pieces(Them);
|
|
safe &= ~attackedBy[Us][ALL_PIECES] | (weak & attackedBy2[Them]);
|
|
|
|
b1 = attacks_bb<ROOK >(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN));
|
|
b2 = attacks_bb<BISHOP>(ksq, pos.pieces() ^ pos.pieces(Us, QUEEN));
|
|
|
|
// Enemy rooks checks
|
|
rookChecks = b1 & safe & attackedBy[Them][ROOK];
|
|
if (rookChecks)
|
|
kingDanger += more_than_one(rookChecks) ? RookSafeCheck * 175/100
|
|
: RookSafeCheck;
|
|
else
|
|
unsafeChecks |= b1 & attackedBy[Them][ROOK];
|
|
|
|
// Enemy queen safe checks: we count them only if they are from squares from
|
|
// which we can't give a rook check, because rook checks are more valuable.
|
|
queenChecks = (b1 | b2)
|
|
& attackedBy[Them][QUEEN]
|
|
& safe
|
|
& ~attackedBy[Us][QUEEN]
|
|
& ~rookChecks;
|
|
if (queenChecks)
|
|
kingDanger += more_than_one(queenChecks) ? QueenSafeCheck * 145/100
|
|
: QueenSafeCheck;
|
|
|
|
// Enemy bishops checks: we count them only if they are from squares from
|
|
// which we can't give a queen check, because queen checks are more valuable.
|
|
bishopChecks = b2
|
|
& attackedBy[Them][BISHOP]
|
|
& safe
|
|
& ~queenChecks;
|
|
if (bishopChecks)
|
|
kingDanger += more_than_one(bishopChecks) ? BishopSafeCheck * 3/2
|
|
: BishopSafeCheck;
|
|
else
|
|
unsafeChecks |= b2 & attackedBy[Them][BISHOP];
|
|
|
|
// Enemy knights checks
|
|
knightChecks = pos.attacks_from<KNIGHT>(ksq) & attackedBy[Them][KNIGHT];
|
|
if (knightChecks & safe)
|
|
kingDanger += more_than_one(knightChecks & safe) ? KnightSafeCheck * 162/100
|
|
: KnightSafeCheck;
|
|
else
|
|
unsafeChecks |= knightChecks;
|
|
|
|
// Find the squares that opponent attacks in our king flank, the squares
|
|
// which they attack twice in that flank, and the squares that we defend.
|
|
b1 = attackedBy[Them][ALL_PIECES] & KingFlank[file_of(ksq)] & Camp;
|
|
b2 = b1 & attackedBy2[Them];
|
|
b3 = attackedBy[Us][ALL_PIECES] & KingFlank[file_of(ksq)] & Camp;
|
|
|
|
int kingFlankAttack = popcount(b1) + popcount(b2);
|
|
int kingFlankDefense = popcount(b3);
|
|
|
|
kingDanger += kingAttackersCount[Them] * kingAttackersWeight[Them]
|
|
+ 185 * popcount(kingRing[Us] & weak)
|
|
+ 148 * popcount(unsafeChecks)
|
|
+ 98 * popcount(pos.blockers_for_king(Us))
|
|
+ 69 * kingAttacksCount[Them]
|
|
+ 3 * kingFlankAttack * kingFlankAttack / 8
|
|
+ mg_value(mobility[Them] - mobility[Us])
|
|
- 873 * !pos.count<QUEEN>(Them)
|
|
- 100 * bool(attackedBy[Us][KNIGHT] & attackedBy[Us][KING])
|
|
- 6 * mg_value(score) / 8
|
|
- 4 * kingFlankDefense
|
|
+ 37;
|
|
|
|
// Transform the kingDanger units into a Score, and subtract it from the evaluation
|
|
if (kingDanger > 100)
|
|
score -= make_score(kingDanger * kingDanger / 4096, kingDanger / 16);
|
|
|
|
// Penalty when our king is on a pawnless flank
|
|
if (!(pos.pieces(PAWN) & KingFlank[file_of(ksq)]))
|
|
score -= PawnlessFlank;
|
|
|
|
// Penalty if king flank is under attack, potentially moving toward the king
|
|
score -= FlankAttacks * kingFlankAttack;
|
|
|
|
if (T)
|
|
Trace::add(KING, Us, score);
|
|
|
|
return score;
|
|
}
|
|
|
|
|
|
// Evaluation::threats() assigns bonuses according to the types of the
|
|
// attacking and the attacked pieces.
|
|
template<Tracing T> template<Color Us>
|
|
Score Evaluation<T>::threats() const {
|
|
|
|
constexpr Color Them = ~Us;
|
|
constexpr Direction Up = pawn_push(Us);
|
|
constexpr Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
|
|
|
|
Bitboard b, weak, defended, nonPawnEnemies, stronglyProtected, safe;
|
|
Score score = SCORE_ZERO;
|
|
|
|
// Non-pawn enemies
|
|
nonPawnEnemies = pos.pieces(Them) & ~pos.pieces(PAWN);
|
|
|
|
// Squares strongly protected by the enemy, either because they defend the
|
|
// square with a pawn, or because they defend the square twice and we don't.
|
|
stronglyProtected = attackedBy[Them][PAWN]
|
|
| (attackedBy2[Them] & ~attackedBy2[Us]);
|
|
|
|
// Non-pawn enemies, strongly protected
|
|
defended = nonPawnEnemies & stronglyProtected;
|
|
|
|
// Enemies not strongly protected and under our attack
|
|
weak = pos.pieces(Them) & ~stronglyProtected & attackedBy[Us][ALL_PIECES];
|
|
|
|
// Bonus according to the kind of attacking pieces
|
|
if (defended | weak)
|
|
{
|
|
b = (defended | weak) & (attackedBy[Us][KNIGHT] | attackedBy[Us][BISHOP]);
|
|
while (b)
|
|
score += ThreatByMinor[type_of(pos.piece_on(pop_lsb(&b)))];
|
|
|
|
b = weak & attackedBy[Us][ROOK];
|
|
while (b)
|
|
score += ThreatByRook[type_of(pos.piece_on(pop_lsb(&b)))];
|
|
|
|
if (weak & attackedBy[Us][KING])
|
|
score += ThreatByKing;
|
|
|
|
b = ~attackedBy[Them][ALL_PIECES]
|
|
| (nonPawnEnemies & attackedBy2[Us]);
|
|
score += Hanging * popcount(weak & b);
|
|
|
|
// Additional bonus if weak piece is only protected by a queen
|
|
score += WeakQueenProtection * popcount(weak & attackedBy[Them][QUEEN]);
|
|
}
|
|
|
|
// Bonus for restricting their piece moves
|
|
b = attackedBy[Them][ALL_PIECES]
|
|
& ~stronglyProtected
|
|
& attackedBy[Us][ALL_PIECES];
|
|
score += RestrictedPiece * popcount(b);
|
|
|
|
// Protected or unattacked squares
|
|
safe = ~attackedBy[Them][ALL_PIECES] | attackedBy[Us][ALL_PIECES];
|
|
|
|
// Bonus for attacking enemy pieces with our relatively safe pawns
|
|
b = pos.pieces(Us, PAWN) & safe;
|
|
b = pawn_attacks_bb<Us>(b) & nonPawnEnemies;
|
|
score += ThreatBySafePawn * popcount(b);
|
|
|
|
// Find squares where our pawns can push on the next move
|
|
b = shift<Up>(pos.pieces(Us, PAWN)) & ~pos.pieces();
|
|
b |= shift<Up>(b & TRank3BB) & ~pos.pieces();
|
|
|
|
// Keep only the squares which are relatively safe
|
|
b &= ~attackedBy[Them][PAWN] & safe;
|
|
|
|
// Bonus for safe pawn threats on the next move
|
|
b = pawn_attacks_bb<Us>(b) & nonPawnEnemies;
|
|
score += ThreatByPawnPush * popcount(b);
|
|
|
|
// Bonus for threats on the next moves against enemy queen
|
|
if (pos.count<QUEEN>(Them) == 1)
|
|
{
|
|
Square s = pos.square<QUEEN>(Them);
|
|
safe = mobilityArea[Us] & ~stronglyProtected;
|
|
|
|
b = attackedBy[Us][KNIGHT] & pos.attacks_from<KNIGHT>(s);
|
|
|
|
score += KnightOnQueen * popcount(b & safe);
|
|
|
|
b = (attackedBy[Us][BISHOP] & pos.attacks_from<BISHOP>(s))
|
|
| (attackedBy[Us][ROOK ] & pos.attacks_from<ROOK >(s));
|
|
|
|
score += SliderOnQueen * popcount(b & safe & attackedBy2[Us]);
|
|
}
|
|
|
|
if (T)
|
|
Trace::add(THREAT, Us, score);
|
|
|
|
return score;
|
|
}
|
|
|
|
// Evaluation::passed() evaluates the passed pawns and candidate passed
|
|
// pawns of the given color.
|
|
|
|
template<Tracing T> template<Color Us>
|
|
Score Evaluation<T>::passed() const {
|
|
|
|
constexpr Color Them = ~Us;
|
|
constexpr Direction Up = pawn_push(Us);
|
|
constexpr Direction Down = -Up;
|
|
|
|
auto king_proximity = [&](Color c, Square s) {
|
|
return std::min(distance(pos.square<KING>(c), s), 5);
|
|
};
|
|
|
|
Bitboard b, bb, squaresToQueen, unsafeSquares, candidatePassers, leverable;
|
|
Score score = SCORE_ZERO;
|
|
|
|
b = pe->passed_pawns(Us);
|
|
|
|
candidatePassers = b & shift<Down>(pos.pieces(Them, PAWN));
|
|
if (candidatePassers)
|
|
{
|
|
// Can we lever the blocker of a candidate passer?
|
|
leverable = shift<Up>(pos.pieces(Us, PAWN))
|
|
& ~pos.pieces(Them)
|
|
& (~attackedBy2[Them] | attackedBy[Us][ALL_PIECES])
|
|
& (~(attackedBy[Them][KNIGHT] | attackedBy[Them][BISHOP])
|
|
| (attackedBy[Us ][KNIGHT] | attackedBy[Us ][BISHOP]));
|
|
|
|
// Remove candidate otherwise
|
|
b &= ~candidatePassers
|
|
| shift<WEST>(leverable)
|
|
| shift<EAST>(leverable);
|
|
}
|
|
|
|
while (b)
|
|
{
|
|
Square s = pop_lsb(&b);
|
|
|
|
assert(!(pos.pieces(Them, PAWN) & forward_file_bb(Us, s + Up)));
|
|
|
|
int r = relative_rank(Us, s);
|
|
|
|
Score bonus = PassedRank[r];
|
|
|
|
if (r > RANK_3)
|
|
{
|
|
int w = 5 * r - 13;
|
|
Square blockSq = s + Up;
|
|
|
|
// Adjust bonus based on the king's proximity
|
|
bonus += make_score(0, ( (king_proximity(Them, blockSq) * 19) / 4
|
|
- king_proximity(Us, blockSq) * 2) * w);
|
|
|
|
// If blockSq is not the queening square then consider also a second push
|
|
if (r != RANK_7)
|
|
bonus -= make_score(0, king_proximity(Us, blockSq + Up) * w);
|
|
|
|
// If the pawn is free to advance, then increase the bonus
|
|
if (pos.empty(blockSq))
|
|
{
|
|
squaresToQueen = forward_file_bb(Us, s);
|
|
unsafeSquares = passed_pawn_span(Us, s);
|
|
|
|
bb = forward_file_bb(Them, s) & pos.pieces(ROOK, QUEEN);
|
|
|
|
if (!(pos.pieces(Them) & bb))
|
|
unsafeSquares &= attackedBy[Them][ALL_PIECES];
|
|
|
|
// If there are no enemy attacks on passed pawn span, assign a big bonus.
|
|
// Otherwise assign a smaller bonus if the path to queen is not attacked
|
|
// and even smaller bonus if it is attacked but block square is not.
|
|
int k = !unsafeSquares ? 35 :
|
|
!(unsafeSquares & squaresToQueen) ? 20 :
|
|
!(unsafeSquares & blockSq) ? 9 :
|
|
0 ;
|
|
|
|
// Assign a larger bonus if the block square is defended
|
|
if ((pos.pieces(Us) & bb) || (attackedBy[Us][ALL_PIECES] & blockSq))
|
|
k += 5;
|
|
|
|
bonus += make_score(k * w, k * w);
|
|
}
|
|
} // r > RANK_3
|
|
|
|
score += bonus - PassedFile * edge_distance(file_of(s));
|
|
}
|
|
|
|
if (T)
|
|
Trace::add(PASSED, Us, score);
|
|
|
|
return score;
|
|
}
|
|
|
|
|
|
// Evaluation::space() computes the space evaluation for a given side. The
|
|
// space evaluation is a simple bonus based on the number of safe squares
|
|
// available for minor pieces on the central four files on ranks 2--4. Safe
|
|
// squares one, two or three squares behind a friendly pawn are counted
|
|
// twice. Finally, the space bonus is multiplied by a weight. The aim is to
|
|
// improve play on game opening.
|
|
|
|
template<Tracing T> template<Color Us>
|
|
Score Evaluation<T>::space() const {
|
|
|
|
if (pos.non_pawn_material() < SpaceThreshold)
|
|
return SCORE_ZERO;
|
|
|
|
constexpr Color Them = ~Us;
|
|
constexpr Direction Down = -pawn_push(Us);
|
|
constexpr Bitboard SpaceMask =
|
|
Us == WHITE ? CenterFiles & (Rank2BB | Rank3BB | Rank4BB)
|
|
: CenterFiles & (Rank7BB | Rank6BB | Rank5BB);
|
|
|
|
// Find the available squares for our pieces inside the area defined by SpaceMask
|
|
Bitboard safe = SpaceMask
|
|
& ~pos.pieces(Us, PAWN)
|
|
& ~attackedBy[Them][PAWN];
|
|
|
|
// Find all squares which are at most three squares behind some friendly pawn
|
|
Bitboard behind = pos.pieces(Us, PAWN);
|
|
behind |= shift<Down>(behind);
|
|
behind |= shift<Down+Down>(behind);
|
|
|
|
int bonus = popcount(safe) + popcount(behind & safe & ~attackedBy[Them][ALL_PIECES]);
|
|
int weight = pos.count<ALL_PIECES>(Us) - 3 + std::min(pe->blocked_count(), 9);
|
|
Score score = make_score(bonus * weight * weight / 16, 0);
|
|
|
|
if (T)
|
|
Trace::add(SPACE, Us, score);
|
|
|
|
return score;
|
|
}
|
|
|
|
|
|
// Evaluation::initiative() computes the initiative correction value
|
|
// for the position. It is a second order bonus/malus based on the
|
|
// known attacking/defending status of the players.
|
|
|
|
template<Tracing T>
|
|
Score Evaluation<T>::initiative(Score score) const {
|
|
|
|
int outflanking = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
|
|
- distance<Rank>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
|
|
|
|
bool pawnsOnBothFlanks = (pos.pieces(PAWN) & QueenSide)
|
|
&& (pos.pieces(PAWN) & KingSide);
|
|
|
|
bool almostUnwinnable = outflanking < 0
|
|
&& !pawnsOnBothFlanks;
|
|
|
|
bool infiltration = rank_of(pos.square<KING>(WHITE)) > RANK_4
|
|
|| rank_of(pos.square<KING>(BLACK)) < RANK_5;
|
|
|
|
// Compute the initiative bonus for the attacking side
|
|
int complexity = 9 * pe->passed_count()
|
|
+ 11 * pos.count<PAWN>()
|
|
+ 9 * outflanking
|
|
+ 21 * pawnsOnBothFlanks
|
|
+ 24 * infiltration
|
|
+ 51 * !pos.non_pawn_material()
|
|
- 43 * almostUnwinnable
|
|
-110 ;
|
|
|
|
Value mg = mg_value(score);
|
|
Value eg = eg_value(score);
|
|
|
|
// Now apply the bonus: note that we find the attacking side by extracting the
|
|
// sign of the midgame or endgame values, and that we carefully cap the bonus
|
|
// so that the midgame and endgame scores do not change sign after the bonus.
|
|
int u = ((mg > 0) - (mg < 0)) * Utility::clamp(complexity + 50, -abs(mg), 0);
|
|
int v = ((eg > 0) - (eg < 0)) * std::max(complexity, -abs(eg));
|
|
|
|
if (T)
|
|
Trace::add(INITIATIVE, make_score(u, v));
|
|
|
|
return make_score(u, v);
|
|
}
|
|
|
|
|
|
// Evaluation::scale_factor() computes the scale factor for the winning side
|
|
|
|
template<Tracing T>
|
|
ScaleFactor Evaluation<T>::scale_factor(Value eg) const {
|
|
|
|
Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK;
|
|
int sf = me->scale_factor(pos, strongSide);
|
|
|
|
// If scale is not already specific, scale down the endgame via general heuristics
|
|
if (sf == SCALE_FACTOR_NORMAL)
|
|
{
|
|
if (pos.opposite_bishops())
|
|
{
|
|
if ( pos.non_pawn_material(WHITE) == BishopValueMg
|
|
&& pos.non_pawn_material(BLACK) == BishopValueMg)
|
|
sf = 18 + 4 * popcount(pe->passed_pawns(strongSide));
|
|
else
|
|
sf = 22 + 3 * pos.count<ALL_PIECES>(strongSide);
|
|
}
|
|
else
|
|
sf = std::min(sf, 36 + 7 * pos.count<PAWN>(strongSide));
|
|
|
|
sf = std::max(0, sf - (pos.rule50_count() - 12) / 4);
|
|
}
|
|
|
|
return ScaleFactor(sf);
|
|
}
|
|
|
|
|
|
// Evaluation::value() is the main function of the class. It computes the various
|
|
// parts of the evaluation and returns the value of the position from the point
|
|
// of view of the side to move.
|
|
|
|
template<Tracing T>
|
|
Value Evaluation<T>::value() {
|
|
|
|
assert(!pos.checkers());
|
|
|
|
// Probe the material hash table
|
|
me = Material::probe(pos);
|
|
|
|
// 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);
|
|
|
|
// Initialize score by reading the incrementally updated scores included in
|
|
// the position object (material + piece square tables) and the material
|
|
// imbalance. Score is computed internally from the white point of view.
|
|
Score score = pos.psq_score() + me->imbalance() + pos.this_thread()->contempt;
|
|
|
|
// Probe the pawn hash table
|
|
pe = Pawns::probe(pos);
|
|
score += pe->pawn_score(WHITE) - pe->pawn_score(BLACK);
|
|
|
|
// Early exit if score is high
|
|
Value v = (mg_value(score) + eg_value(score)) / 2;
|
|
if (abs(v) > LazyThreshold + pos.non_pawn_material() / 64)
|
|
return pos.side_to_move() == WHITE ? v : -v;
|
|
|
|
// Main evaluation begins here
|
|
|
|
initialize<WHITE>();
|
|
initialize<BLACK>();
|
|
|
|
// Pieces evaluated first (also populates attackedBy, attackedBy2).
|
|
// Note that the order of evaluation of the terms is left unspecified
|
|
score += pieces<WHITE, KNIGHT>() - pieces<BLACK, KNIGHT>()
|
|
+ pieces<WHITE, BISHOP>() - pieces<BLACK, BISHOP>()
|
|
+ pieces<WHITE, ROOK >() - pieces<BLACK, ROOK >()
|
|
+ pieces<WHITE, QUEEN >() - pieces<BLACK, QUEEN >();
|
|
|
|
score += mobility[WHITE] - mobility[BLACK];
|
|
|
|
// More complex interactions that require fully populated attack bitboards
|
|
score += king< WHITE>() - king< BLACK>()
|
|
+ threats<WHITE>() - threats<BLACK>()
|
|
+ passed< WHITE>() - passed< BLACK>()
|
|
+ space< WHITE>() - space< BLACK>();
|
|
|
|
score += initiative(score);
|
|
|
|
// Interpolate between a middlegame and a (scaled by 'sf') endgame score
|
|
ScaleFactor sf = scale_factor(eg_value(score));
|
|
v = mg_value(score) * int(me->game_phase())
|
|
+ eg_value(score) * int(PHASE_MIDGAME - me->game_phase()) * sf / SCALE_FACTOR_NORMAL;
|
|
|
|
v /= PHASE_MIDGAME;
|
|
|
|
// In case of tracing add all remaining individual evaluation terms
|
|
if (T)
|
|
{
|
|
Trace::add(MATERIAL, pos.psq_score());
|
|
Trace::add(IMBALANCE, me->imbalance());
|
|
Trace::add(PAWN, pe->pawn_score(WHITE), pe->pawn_score(BLACK));
|
|
Trace::add(MOBILITY, mobility[WHITE], mobility[BLACK]);
|
|
Trace::add(TOTAL, score);
|
|
}
|
|
|
|
return (pos.side_to_move() == WHITE ? v : -v) + Tempo; // Side to move point of view
|
|
}
|
|
|
|
} // namespace
|
|
|
|
|
|
/// evaluate() is the evaluator for the outer world. It returns a static
|
|
/// evaluation of the position from the point of view of the side to move.
|
|
|
|
Value Eval::evaluate(const Position& pos) {
|
|
return Evaluation<NO_TRACE>(pos).value();
|
|
}
|
|
|
|
|
|
/// 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.
|
|
|
|
std::string Eval::trace(const Position& pos) {
|
|
|
|
if (pos.checkers())
|
|
return "Total evaluation: none (in check)";
|
|
|
|
std::memset(scores, 0, sizeof(scores));
|
|
|
|
pos.this_thread()->contempt = SCORE_ZERO; // Reset any dynamic contempt
|
|
|
|
Value v = Evaluation<TRACE>(pos).value();
|
|
|
|
v = pos.side_to_move() == WHITE ? v : -v; // Trace scores are from white's point of view
|
|
|
|
std::stringstream ss;
|
|
ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2)
|
|
<< " 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)
|
|
<< " Bishops | " << Term(BISHOP)
|
|
<< " Rooks | " << Term(ROOK)
|
|
<< " Queens | " << Term(QUEEN)
|
|
<< " Mobility | " << Term(MOBILITY)
|
|
<< " King safety | " << Term(KING)
|
|
<< " Threats | " << Term(THREAT)
|
|
<< " Passed | " << Term(PASSED)
|
|
<< " Space | " << Term(SPACE)
|
|
<< " Initiative | " << Term(INITIATIVE)
|
|
<< " ------------+-------------+-------------+------------\n"
|
|
<< " Total | " << Term(TOTAL);
|
|
|
|
ss << "\nTotal evaluation: " << to_cp(v) << " (white side)\n";
|
|
|
|
return ss.str();
|
|
}
|