File size: 46,301 Bytes
bda2ed7 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 |
/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2022 The Stockfish developers (see AUTHORS file)
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 <cstdlib>
#include <cstring> // For std::memset
#include <fstream>
#include <iomanip>
#include <sstream>
#include <iostream>
#include <streambuf>
#include <vector>
#include "bitboard.h"
#include "evaluate.h"
#include "material.h"
#include "misc.h"
#include "pawns.h"
#include "thread.h"
#include "timeman.h"
#include "uci.h"
#include "incbin/incbin.h"
// Macro to embed the default efficiently updatable neural network (NNUE) file
// data in the engine binary (using incbin.h, by Dale Weiler).
// This macro invocation will declare the following three variables
// const unsigned char gEmbeddedNNUEData[]; // a pointer to the embedded data
// const unsigned char *const gEmbeddedNNUEEnd; // a marker to the end
// const unsigned int gEmbeddedNNUESize; // the size of the embedded file
// Note that this does not work in Microsoft Visual Studio.
#if !defined(_MSC_VER) && !defined(NNUE_EMBEDDING_OFF)
INCBIN(EmbeddedNNUE, EvalFileDefaultName);
#else
const unsigned char gEmbeddedNNUEData[1] = {0x0};
const unsigned char *const gEmbeddedNNUEEnd = &gEmbeddedNNUEData[1];
const unsigned int gEmbeddedNNUESize = 1;
#endif
using namespace std;
namespace Stockfish {
namespace Eval {
bool useNNUE;
string currentEvalFileName = "None";
/// NNUE::init() tries to load a NNUE network at startup time, or when the engine
/// receives a UCI command "setoption name EvalFile value nn-[a-z0-9]{12}.nnue"
/// The name of the NNUE network is always retrieved from the EvalFile option.
/// We search the given network in three locations: internally (the default
/// network may be embedded in the binary), in the active working directory and
/// in the engine directory. Distro packagers may define the DEFAULT_NNUE_DIRECTORY
/// variable to have the engine search in a special directory in their distro.
void NNUE::init() {
useNNUE = Options["Use NNUE"];
if (!useNNUE)
return;
string eval_file = string(Options["EvalFile"]);
if (eval_file.empty())
eval_file = EvalFileDefaultName;
#if defined(DEFAULT_NNUE_DIRECTORY)
#define stringify2(x) #x
#define stringify(x) stringify2(x)
vector<string> dirs = { "<internal>" , "" , CommandLine::binaryDirectory , stringify(DEFAULT_NNUE_DIRECTORY) };
#else
vector<string> dirs = { "<internal>" , "" , CommandLine::binaryDirectory };
#endif
for (string directory : dirs)
if (currentEvalFileName != eval_file)
{
if (directory != "<internal>")
{
ifstream stream(directory + eval_file, ios::binary);
if (load_eval(eval_file, stream))
currentEvalFileName = eval_file;
}
if (directory == "<internal>" && eval_file == EvalFileDefaultName)
{
// C++ way to prepare a buffer for a memory stream
class MemoryBuffer : public basic_streambuf<char> {
public: MemoryBuffer(char* p, size_t n) { setg(p, p, p + n); setp(p, p + n); }
};
MemoryBuffer buffer(const_cast<char*>(reinterpret_cast<const char*>(gEmbeddedNNUEData)),
size_t(gEmbeddedNNUESize));
(void) gEmbeddedNNUEEnd; // Silence warning on unused variable
istream stream(&buffer);
if (load_eval(eval_file, stream))
currentEvalFileName = eval_file;
}
}
}
/// NNUE::verify() verifies that the last net used was loaded successfully
void NNUE::verify() {
string eval_file = string(Options["EvalFile"]);
if (eval_file.empty())
eval_file = EvalFileDefaultName;
if (useNNUE && currentEvalFileName != eval_file)
{
string msg1 = "If the UCI option \"Use NNUE\" is set to true, network evaluation parameters compatible with the engine must be available.";
string msg2 = "The option is set to true, but the network file " + eval_file + " was not loaded successfully.";
string msg3 = "The UCI option EvalFile might need to specify the full path, including the directory name, to the network file.";
string msg4 = "The default net can be downloaded from: https://tests.stockfishchess.org/api/nn/" + std::string(EvalFileDefaultName);
string msg5 = "The engine will be terminated now.";
sync_cout << "info string ERROR: " << msg1 << sync_endl;
sync_cout << "info string ERROR: " << msg2 << sync_endl;
sync_cout << "info string ERROR: " << msg3 << sync_endl;
sync_cout << "info string ERROR: " << msg4 << sync_endl;
sync_cout << "info string ERROR: " << msg5 << sync_endl;
exit(EXIT_FAILURE);
}
if (useNNUE)
sync_cout << "info string NNUE evaluation using " << eval_file << " enabled" << sync_endl;
else
sync_cout << "info string classical evaluation enabled" << sync_endl;
}
}
namespace Trace {
enum Tracing { NO_TRACE, TRACE };
enum Term { // The first 8 entries are reserved for PieceType
MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, WINNABLE, TOTAL, TERM_NB
};
Score scores[TERM_NB][COLOR_NB];
double to_cp(Value v) { return double(v) / UCI::NormalizeToPawnValue; }
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 == WINNABLE || 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 LazyThreshold1 = Value(3631);
constexpr Value LazyThreshold2 = Value(2084);
constexpr Value SpaceThreshold = Value(11551);
// KingAttackWeights[PieceType] contains king attack weights by piece type
constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 76, 46, 45, 14 };
// SafeCheck[PieceType][single/multiple] contains safe check bonus by piece type,
// higher if multiple safe checks are possible for that piece type.
constexpr int SafeCheck[][2] = {
{}, {}, {805, 1292}, {650, 984}, {1071, 1886}, {730, 1128}
};
#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,-79), S(-53,-57), S(-12,-31), S( -3,-17), S( 3, 7), S( 12, 13), // Knight
S( 21, 16), S( 28, 21), S( 37, 26) },
{ S(-47,-59), S(-20,-25), S( 14, -8), S( 29, 12), S( 39, 21), S( 53, 40), // Bishop
S( 53, 56), S( 60, 58), S( 62, 65), S( 69, 72), S( 78, 78), S( 83, 87),
S( 91, 88), S( 96, 98) },
{ S(-60,-82), S(-24,-15), S( 0, 17) ,S( 3, 43), S( 4, 72), S( 14,100), // Rook
S( 20,102), S( 30,122), S( 41,133), S(41 ,139), S( 41,153), S( 45,160),
S( 57,165), S( 58,170), S( 67,175) },
{ S(-29,-49), S(-16,-29), S( -8, -8), S( -8, 17), S( 18, 39), S( 25, 54), // Queen
S( 23, 59), S( 37, 73), S( 41, 76), S( 54, 95), S( 65, 95) ,S( 68,101),
S( 69,124), S( 70,128), S( 70,132), S( 70,133) ,S( 71,136), S( 72,140),
S( 74,147), S( 76,149), S( 90,153), S(104,169), S(105,171), S(106,171),
S(112,178), S(114,185), S(114,187), S(119,221) }
};
// BishopPawns[distance from edge] contains a file-dependent penalty for pawns on
// squares of the same color as our bishop.
constexpr Score BishopPawns[int(FILE_NB) / 2] = {
S(3, 8), S(3, 9), S(2, 7), S(3, 7)
};
// KingProtector[knight/bishop] contains penalty for each distance unit to own king
constexpr Score KingProtector[] = { S(9, 9), S(7, 9) };
// Outpost[knight/bishop] contains bonuses for each knight or bishop occupying a
// pawn protected square on rank 4 to 6 which is also safe from a pawn attack.
constexpr Score Outpost[] = { S(54, 34), S(31, 25) };
// PassedRank[Rank] contains a bonus according to the rank of a passed pawn
constexpr Score PassedRank[RANK_NB] = {
S(0, 0), S(2, 38), S(15, 36), S(22, 50), S(64, 81), S(166, 184), S(284, 269)
};
constexpr Score RookOnClosedFile = S(10, 5);
constexpr Score RookOnOpenFile[] = { S(18, 8), S(49, 26) };
// 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(6, 37), S(64, 50), S(82, 57), S(103, 130), S(81, 163)
};
constexpr Score ThreatByRook[PIECE_TYPE_NB] = {
S(0, 0), S(3, 44), S(36, 71), S(44, 59), S(0, 39), S(60, 39)
};
constexpr Value CorneredBishop = Value(50);
// Assorted bonuses and penalties
constexpr Score UncontestedOutpost = S( 0, 10);
constexpr Score BishopOnKingRing = S( 24, 0);
constexpr Score BishopXRayPawns = S( 4, 5);
constexpr Score FlankAttacks = S( 8, 0);
constexpr Score Hanging = S( 72, 40);
constexpr Score KnightOnQueen = S( 16, 11);
constexpr Score LongDiagonalBishop = S( 45, 0);
constexpr Score MinorBehindPawn = S( 18, 3);
constexpr Score PassedFile = S( 13, 8);
constexpr Score PawnlessFlank = S( 19, 97);
constexpr Score ReachableOutpost = S( 33, 19);
constexpr Score RestrictedPiece = S( 6, 7);
constexpr Score RookOnKingRing = S( 16, 0);
constexpr Score SliderOnQueen = S( 62, 21);
constexpr Score ThreatByKing = S( 24, 87);
constexpr Score ThreatByPawnPush = S( 48, 39);
constexpr Score ThreatBySafePawn = S(167, 99);
constexpr Score TrappedRook = S( 55, 13);
constexpr Score WeakQueenProtection = S( 14, 0);
constexpr Score WeakQueen = S( 57, 19);
#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;
Value winnable(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] = attacks_bb<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(std::clamp(file_of(ksq), FILE_B, FILE_G),
std::clamp(rank_of(ksq), RANK_2, RANK_7));
kingRing[Us] = attacks_bb<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);
Bitboard b1 = pos.pieces(Us, Pt);
Bitboard b, bb;
Score score = SCORE_ZERO;
attackedBy[Us][Pt] = 0;
while (b1)
{
Square s = pop_lsb(b1);
// 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))
: attacks_bb<Pt>(s, pos.pieces());
if (pos.blockers_for_king(Us) & s)
b &= line_bb(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]);
}
else if (Pt == ROOK && (file_bb(s) & kingRing[Them]))
score += RookOnKingRing;
else if (Pt == BISHOP && (attacks_bb<BISHOP>(s, pos.pieces(PAWN)) & kingRing[Them]))
score += BishopOnKingRing;
int mob = popcount(b & mobilityArea[Us]);
mobility[Us] += MobilityBonus[Pt - 2][mob];
if (Pt == BISHOP || Pt == KNIGHT)
{
// Bonus if the piece is on an outpost square or can reach one
// Bonus for knights (UncontestedOutpost) if few relevant targets
bb = OutpostRanks & (attackedBy[Us][PAWN] | shift<Down>(pos.pieces(PAWN)))
& ~pe->pawn_attacks_span(Them);
Bitboard targets = pos.pieces(Them) & ~pos.pieces(PAWN);
if ( Pt == KNIGHT
&& bb & s & ~CenterFiles // on a side outpost
&& !(b & targets) // no relevant attacks
&& (!more_than_one(targets & (s & QueenSide ? QueenSide : KingSide))))
score += UncontestedOutpost * popcount(pos.pieces(PAWN) & (s & QueenSide ? QueenSide : KingSide));
else if (bb & s)
score += Outpost[Pt == BISHOP];
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 -= KingProtector[Pt == BISHOP] * distance(pos.square<KING>(Us), s);
if constexpr (Pt == BISHOP)
{
// Penalty according to the number of our 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[edge_distance(file_of(s))] * pos.pawns_on_same_color_squares(Us, s)
* (!(attackedBy[Us][PAWN] & s) + popcount(blocked & CenterFiles));
// Penalty for all enemy pawns x-rayed
score -= BishopXRayPawns * popcount(attacks_bb<BISHOP>(s) & pos.pieces(Them, PAWN));
// 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)) ? 4 * make_score(CorneredBishop, CorneredBishop)
: 3 * make_score(CorneredBishop, CorneredBishop);
}
}
}
if constexpr (Pt == ROOK)
{
// Bonuses for rook on a (semi-)open or closed file
if (pos.is_on_semiopen_file(Us, s))
{
score += RookOnOpenFile[pos.is_on_semiopen_file(Them, s)];
}
else
{
// If our pawn on this file is blocked, increase penalty
if ( pos.pieces(Us, PAWN)
& shift<Down>(pos.pieces())
& file_bb(s))
{
score -= RookOnClosedFile;
}
// Penalty when trapped by the king, even more if the king cannot castle
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 constexpr (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 constexpr (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 & attackedBy[Them][ROOK] & safe;
if (rookChecks)
kingDanger += SafeCheck[ROOK][more_than_one(rookChecks)];
else
unsafeChecks |= b1 & attackedBy[Them][ROOK];
// Enemy queen safe checks: count them only if the checks are from squares from
// which opponent cannot give a rook check, because rook checks are more valuable.
queenChecks = (b1 | b2) & attackedBy[Them][QUEEN] & safe
& ~(attackedBy[Us][QUEEN] | rookChecks);
if (queenChecks)
kingDanger += SafeCheck[QUEEN][more_than_one(queenChecks)];
// Enemy bishops checks: count them only if they are from squares from which
// opponent cannot give a queen check, because queen checks are more valuable.
bishopChecks = b2 & attackedBy[Them][BISHOP] & safe
& ~queenChecks;
if (bishopChecks)
kingDanger += SafeCheck[BISHOP][more_than_one(bishopChecks)];
else
unsafeChecks |= b2 & attackedBy[Them][BISHOP];
// Enemy knights checks
knightChecks = attacks_bb<KNIGHT>(ksq) & attackedBy[Them][KNIGHT];
if (knightChecks & safe)
kingDanger += SafeCheck[KNIGHT][more_than_one(knightChecks & safe)];
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] // (~10 Elo)
+ 183 * popcount(kingRing[Us] & weak) // (~15 Elo)
+ 148 * popcount(unsafeChecks) // (~4 Elo)
+ 98 * popcount(pos.blockers_for_king(Us)) // (~2 Elo)
+ 69 * kingAttacksCount[Them] // (~0.5 Elo)
+ 3 * kingFlankAttack * kingFlankAttack / 8 // (~0.5 Elo)
+ mg_value(mobility[Them] - mobility[Us]) // (~0.5 Elo)
- 873 * !pos.count<QUEEN>(Them) // (~24 Elo)
- 100 * bool(attackedBy[Us][KNIGHT] & attackedBy[Us][KING]) // (~5 Elo)
- 6 * mg_value(score) / 8 // (~8 Elo)
- 4 * kingFlankDefense // (~5 Elo)
+ 37; // (~0.5 Elo)
// 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 constexpr (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)
{
bool queenImbalance = pos.count<QUEEN>() == 1;
Square s = pos.square<QUEEN>(Them);
safe = mobilityArea[Us]
& ~pos.pieces(Us, PAWN)
& ~stronglyProtected;
b = attackedBy[Us][KNIGHT] & attacks_bb<KNIGHT>(s);
score += KnightOnQueen * popcount(b & safe) * (1 + queenImbalance);
b = (attackedBy[Us][BISHOP] & attacks_bb<BISHOP>(s, pos.pieces()))
| (attackedBy[Us][ROOK ] & attacks_bb<ROOK >(s, pos.pieces()));
score += SliderOnQueen * popcount(b & safe & attackedBy2[Us]) * (1 + queenImbalance);
}
if constexpr (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, blockedPassers, helpers;
Score score = SCORE_ZERO;
b = pe->passed_pawns(Us);
blockedPassers = b & shift<Down>(pos.pieces(Them, PAWN));
if (blockedPassers)
{
helpers = shift<Up>(pos.pieces(Us, PAWN))
& ~pos.pieces(Them)
& (~attackedBy2[Them] | attackedBy[Us][ALL_PIECES]);
// Remove blocked candidate passers that don't have help to pass
b &= ~blockedPassers
| shift<WEST>(helpers)
| shift<EAST>(helpers);
}
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] | pos.pieces(Them);
// If there are no enemy pieces or attacks on passed pawn span, assign a big bonus.
// Or if there is some, but they are all attacked by our pawns, assign a bit smaller 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 ? 36 :
!(unsafeSquares & ~attackedBy[Us][PAWN]) ? 30 :
!(unsafeSquares & squaresToQueen) ? 17 :
!(unsafeSquares & blockSq) ? 7 :
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 constexpr (T)
Trace::add(PASSED, Us, score);
return score;
}
// Evaluation::space() computes a space evaluation for a given side, aiming to improve game
// play in the opening. It is based on the number of safe squares on the four central files
// on ranks 2 to 4. Completely safe squares behind a friendly pawn are counted twice.
// Finally, the space bonus is multiplied by a weight which decreases according to occupancy.
template<Tracing T> template<Color Us>
Score Evaluation<T>::space() const {
// Early exit if, for example, both queens or 6 minor pieces have been exchanged
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);
// Compute space score based on the number of safe squares and number of our pieces
// increased with number of total blocked pawns in position.
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 constexpr (T)
Trace::add(SPACE, Us, score);
return score;
}
// Evaluation::winnable() adjusts the midgame and endgame score components, based on
// the known attacking/defending status of the players. The final value is derived
// by interpolation from the midgame and endgame values.
template<Tracing T>
Value Evaluation<T>::winnable(Score score) const {
int outflanking = distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
+ int(rank_of(pos.square<KING>(WHITE)) - rank_of(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()
+ 12 * 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)) * std::clamp(complexity + 50, -abs(mg), 0);
int v = ((eg > 0) - (eg < 0)) * std::max(complexity, -abs(eg));
mg += u;
eg += v;
// Compute the scale factor for the winning side
Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK;
int sf = me->scale_factor(pos, strongSide);
// If scale factor is not already specific, scale up/down via general heuristics
if (sf == SCALE_FACTOR_NORMAL)
{
if (pos.opposite_bishops())
{
// For pure opposite colored bishops endgames use scale factor
// based on the number of passed pawns of the strong side.
if ( pos.non_pawn_material(WHITE) == BishopValueMg
&& pos.non_pawn_material(BLACK) == BishopValueMg)
sf = 18 + 4 * popcount(pe->passed_pawns(strongSide));
// For every other opposite colored bishops endgames use scale factor
// based on the number of all pieces of the strong side.
else
sf = 22 + 3 * pos.count<ALL_PIECES>(strongSide);
}
// For rook endgames with strong side not having overwhelming pawn number advantage
// and its pawns being on one flank and weak side protecting its pieces with a king
// use lower scale factor.
else if ( pos.non_pawn_material(WHITE) == RookValueMg
&& pos.non_pawn_material(BLACK) == RookValueMg
&& pos.count<PAWN>(strongSide) - pos.count<PAWN>(~strongSide) <= 1
&& bool(KingSide & pos.pieces(strongSide, PAWN)) != bool(QueenSide & pos.pieces(strongSide, PAWN))
&& (attacks_bb<KING>(pos.square<KING>(~strongSide)) & pos.pieces(~strongSide, PAWN)))
sf = 36;
// For queen vs no queen endgames use scale factor
// based on number of minors of side that doesn't have queen.
else if (pos.count<QUEEN>() == 1)
sf = 37 + 3 * (pos.count<QUEEN>(WHITE) == 1 ? pos.count<BISHOP>(BLACK) + pos.count<KNIGHT>(BLACK)
: pos.count<BISHOP>(WHITE) + pos.count<KNIGHT>(WHITE));
// In every other case use scale factor based on
// the number of pawns of the strong side reduced if pawns are on a single flank.
else
sf = std::min(sf, 36 + 7 * pos.count<PAWN>(strongSide)) - 4 * !pawnsOnBothFlanks;
// Reduce scale factor in case of pawns being on a single flank
sf -= 4 * !pawnsOnBothFlanks;
}
// Interpolate between the middlegame and (scaled by 'sf') endgame score
v = mg * int(me->game_phase())
+ eg * int(PHASE_MIDGAME - me->game_phase()) * ScaleFactor(sf) / SCALE_FACTOR_NORMAL;
v /= PHASE_MIDGAME;
if constexpr (T)
{
Trace::add(WINNABLE, make_score(u, eg * ScaleFactor(sf) / SCALE_FACTOR_NORMAL - eg_value(score)));
Trace::add(TOTAL, make_score(mg, eg * ScaleFactor(sf) / SCALE_FACTOR_NORMAL));
}
return Value(v);
}
// 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();
// Probe the pawn hash table
pe = Pawns::probe(pos);
score += pe->pawn_score(WHITE) - pe->pawn_score(BLACK);
// Early exit if score is high
auto lazy_skip = [&](Value lazyThreshold) {
return abs(mg_value(score) + eg_value(score)) > lazyThreshold
+ std::abs(pos.this_thread()->bestValue) * 5 / 4
+ pos.non_pawn_material() / 32;
};
if (lazy_skip(LazyThreshold1))
goto make_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>()
+ passed< WHITE>() - passed< BLACK>();
if (lazy_skip(LazyThreshold2))
goto make_v;
score += threats<WHITE>() - threats<BLACK>()
+ space< WHITE>() - space< BLACK>();
make_v:
// Derive single value from mg and eg parts of score
Value v = winnable(score);
// In case of tracing add all remaining individual evaluation terms
if constexpr (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]);
}
// Evaluation grain
v = (v / 16) * 16;
// Side to move point of view
v = (pos.side_to_move() == WHITE ? v : -v);
return v;
}
} // namespace Eval
/// 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, int* complexity) {
Value v;
Value psq = pos.psq_eg_stm();
// We use the much less accurate but faster Classical eval when the NNUE
// option is set to false. Otherwise we use the NNUE eval unless the
// PSQ advantage is decisive and several pieces remain. (~3 Elo)
bool useClassical = !useNNUE || (pos.count<ALL_PIECES>() > 7 && abs(psq) > 1760);
if (useClassical)
v = Evaluation<NO_TRACE>(pos).value();
else
{
int nnueComplexity;
int scale = 1064 + 106 * pos.non_pawn_material() / 5120;
Color stm = pos.side_to_move();
Value optimism = pos.this_thread()->optimism[stm];
Value nnue = NNUE::evaluate(pos, true, &nnueComplexity);
// Blend nnue complexity with (semi)classical complexity
nnueComplexity = ( 416 * nnueComplexity
+ 424 * abs(psq - nnue)
+ (optimism > 0 ? int(optimism) * int(psq - nnue) : 0)
) / 1024;
// Return hybrid NNUE complexity to caller
if (complexity)
*complexity = nnueComplexity;
optimism = optimism * (269 + nnueComplexity) / 256;
v = (nnue * scale + optimism * (scale - 754)) / 1024;
}
// Damp down the evaluation linearly when shuffling
v = v * (195 - pos.rule50_count()) / 211;
// Guarantee evaluation does not hit the tablebase range
v = std::clamp(v, VALUE_TB_LOSS_IN_MAX_PLY + 1, VALUE_TB_WIN_IN_MAX_PLY - 1);
// When not using NNUE, return classical complexity to caller
if (complexity && (!useNNUE || useClassical))
*complexity = abs(v - psq);
return v;
}
/// 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.
/// Trace scores are from white's point of view
std::string Eval::trace(Position& pos) {
if (pos.checkers())
return "Final evaluation: none (in check)";
std::stringstream ss;
ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2);
Value v;
std::memset(scores, 0, sizeof(scores));
// Reset any global variable used in eval
pos.this_thread()->bestValue = VALUE_ZERO;
pos.this_thread()->optimism[WHITE] = VALUE_ZERO;
pos.this_thread()->optimism[BLACK] = VALUE_ZERO;
v = Evaluation<TRACE>(pos).value();
ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2)
<< " Contributing terms for the classical eval:\n"
<< "+------------+-------------+-------------+-------------+\n"
<< "| 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)
<< "| Winnable | " << Term(WINNABLE)
<< "+------------+-------------+-------------+-------------+\n"
<< "| Total | " << Term(TOTAL)
<< "+------------+-------------+-------------+-------------+\n";
if (Eval::useNNUE)
ss << '\n' << NNUE::trace(pos) << '\n';
ss << std::showpoint << std::showpos << std::fixed << std::setprecision(2) << std::setw(15);
v = pos.side_to_move() == WHITE ? v : -v;
ss << "\nClassical evaluation " << to_cp(v) << " (white side)\n";
if (Eval::useNNUE)
{
v = NNUE::evaluate(pos, false);
v = pos.side_to_move() == WHITE ? v : -v;
ss << "NNUE evaluation " << to_cp(v) << " (white side)\n";
}
v = evaluate(pos);
v = pos.side_to_move() == WHITE ? v : -v;
ss << "Final evaluation " << to_cp(v) << " (white side)";
if (Eval::useNNUE)
ss << " [with scaled NNUE, hybrid, ...]";
ss << "\n";
return ss.str();
}
} // namespace Stockfish
|