2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
6 Stockfish is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 Stockfish is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
35 #include "ucioption.h"
39 //// Local definitions
44 // Struct EvalInfo contains various information computed and collected
45 // by the evaluation functions.
48 // Pointer to pawn hash table entry
51 // attackedBy[color][piece type] is a bitboard representing all squares
52 // attacked by a given color and piece type, attackedBy[color][0] contains
53 // all squares attacked by the given color.
54 Bitboard attackedBy[2][8];
56 // kingZone[color] is the zone around the enemy king which is considered
57 // by the king safety evaluation. This consists of the squares directly
58 // adjacent to the king, and the three (or two, for a king on an edge file)
59 // squares two ranks in front of the king. For instance, if black's king
60 // is on g8, kingZone[WHITE] is a bitboard containing the squares f8, h8,
61 // f7, g7, h7, f6, g6 and h6.
64 // kingAttackersCount[color] is the number of pieces of the given color
65 // which attack a square in the kingZone of the enemy king.
66 int kingAttackersCount[2];
68 // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
69 // given color which attack a square in the kingZone of the enemy king. The
70 // weights of the individual piece types are given by the variables
71 // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
72 // KnightAttackWeight in evaluate.cpp
73 int kingAttackersWeight[2];
75 // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
76 // directly adjacent to the king of the given color. Pieces which attack
77 // more than one square are counted multiple times. For instance, if black's
78 // king is on g8 and there's a white knight on g5, this knight adds
79 // 2 to kingAdjacentZoneAttacksCount[BLACK].
80 int kingAdjacentZoneAttacksCount[2];
83 // Evaluation grain size, must be a power of 2
84 const int GrainSize = 8;
86 // Evaluation weights, initialized from UCI options
87 enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem };
91 #define S(mg, eg) make_score(mg, eg)
93 // Internal evaluation weights. These are applied on top of the evaluation
94 // weights read from UCI parameters. The purpose is to be able to change
95 // the evaluation weights while keeping the default values of the UCI
96 // parameters at 100, which looks prettier.
98 // Values modified by Joona Kiiski
99 const Score WeightsInternal[] = {
100 S(248, 271), S(233, 201), S(252, 259), S(46, 0), S(247, 0), S(259, 0)
103 // MobilityBonus[PieceType][attacked] contains mobility bonuses for middle and
104 // end game, indexed by piece type and number of attacked squares not occupied
105 // by friendly pieces.
106 const Score MobilityBonus[][32] = {
108 { S(-38,-33), S(-25,-23), S(-12,-13), S( 0, -3), S(12, 7), S(25, 17), // Knights
109 S( 31, 22), S( 38, 27), S( 38, 27) },
110 { S(-25,-30), S(-11,-16), S( 3, -2), S(17, 12), S(31, 26), S(45, 40), // Bishops
111 S( 57, 52), S( 65, 60), S( 71, 65), S(74, 69), S(76, 71), S(78, 73),
112 S( 79, 74), S( 80, 75), S( 81, 76), S(81, 76) },
113 { S(-20,-36), S(-14,-19), S( -8, -3), S(-2, 13), S( 4, 29), S(10, 46), // Rooks
114 S( 14, 62), S( 19, 79), S( 23, 95), S(26,106), S(27,111), S(28,114),
115 S( 29,116), S( 30,117), S( 31,118), S(32,118) },
116 { S(-10,-18), S( -8,-13), S( -6, -7), S(-3, -2), S(-1, 3), S( 1, 8), // Queens
117 S( 3, 13), S( 5, 19), S( 8, 23), S(10, 27), S(12, 32), S(15, 34),
118 S( 16, 35), S( 17, 35), S( 18, 35), S(20, 35), S(20, 35), S(20, 35),
119 S( 20, 35), S( 20, 35), S( 20, 35), S(20, 35), S(20, 35), S(20, 35),
120 S( 20, 35), S( 20, 35), S( 20, 35), S(20, 35), S(20, 35), S(20, 35),
121 S( 20, 35), S( 20, 35) }
124 // OutpostBonus[PieceType][Square] contains outpost bonuses of knights and
125 // bishops, indexed by piece type and square (from white's point of view).
126 const Value OutpostBonus[][64] = {
129 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Knights
130 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
131 V(0), V(0), V(4), V(8), V(8), V(4), V(0), V(0),
132 V(0), V(4),V(17),V(26),V(26),V(17), V(4), V(0),
133 V(0), V(8),V(26),V(35),V(35),V(26), V(8), V(0),
134 V(0), V(4),V(17),V(17),V(17),V(17), V(4), V(0) },
136 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Bishops
137 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
138 V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0),
139 V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0),
140 V(0),V(10),V(21),V(21),V(21),V(21),V(10), V(0),
141 V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0) }
144 // ThreatBonus[attacking][attacked] contains threat bonuses according to
145 // which piece type attacks which one.
146 const Score ThreatBonus[][8] = {
148 { S(0, 0), S( 7, 39), S( 0, 0), S(24, 49), S(41,100), S(41,100) }, // KNIGHT
149 { S(0, 0), S( 7, 39), S(24, 49), S( 0, 0), S(41,100), S(41,100) }, // BISHOP
150 { S(0, 0), S(-1, 29), S(15, 49), S(15, 49), S( 0, 0), S(24, 49) }, // ROOK
151 { S(0, 0), S(15, 39), S(15, 39), S(15, 39), S(15, 39), S( 0, 0) } // QUEEN
154 // ThreatedByPawnPenalty[PieceType] contains a penalty according to which
155 // piece type is attacked by an enemy pawn.
156 const Score ThreatedByPawnPenalty[] = {
157 S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
162 // Rooks and queens on the 7th rank (modified by Joona Kiiski)
163 const Score RookOn7thBonus = make_score(47, 98);
164 const Score QueenOn7thBonus = make_score(27, 54);
166 // Rooks on open files (modified by Joona Kiiski)
167 const Score RookOpenFileBonus = make_score(43, 43);
168 const Score RookHalfOpenFileBonus = make_score(19, 19);
170 // Penalty for rooks trapped inside a friendly king which has lost the
172 const Value TrappedRookPenalty = Value(180);
174 // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
175 // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
176 // happen in Chess960 games.
177 const Score TrappedBishopA1H1Penalty = make_score(100, 100);
179 // The SpaceMask[Color] contains the area of the board which is considered
180 // by the space evaluation. In the middle game, each side is given a bonus
181 // based on how many squares inside this area are safe and available for
182 // friendly minor pieces.
183 const Bitboard SpaceMask[] = {
184 (1ULL << SQ_C2) | (1ULL << SQ_D2) | (1ULL << SQ_E2) | (1ULL << SQ_F2) |
185 (1ULL << SQ_C3) | (1ULL << SQ_D3) | (1ULL << SQ_E3) | (1ULL << SQ_F3) |
186 (1ULL << SQ_C4) | (1ULL << SQ_D4) | (1ULL << SQ_E4) | (1ULL << SQ_F4),
187 (1ULL << SQ_C7) | (1ULL << SQ_D7) | (1ULL << SQ_E7) | (1ULL << SQ_F7) |
188 (1ULL << SQ_C6) | (1ULL << SQ_D6) | (1ULL << SQ_E6) | (1ULL << SQ_F6) |
189 (1ULL << SQ_C5) | (1ULL << SQ_D5) | (1ULL << SQ_E5) | (1ULL << SQ_F5)
192 // King danger constants and variables. The king danger scores are taken
193 // from the KingDangerTable[]. Various little "meta-bonuses" measuring
194 // the strength of the enemy attack are added up into an integer, which
195 // is used as an index to KingDangerTable[].
197 // KingAttackWeights[PieceType] contains king attack weights by piece type
198 const int KingAttackWeights[] = { 0, 0, 2, 2, 3, 5 };
200 // Bonuses for enemy's safe checks
201 const int QueenContactCheckBonus = 6;
202 const int RookContactCheckBonus = 4;
203 const int QueenCheckBonus = 3;
204 const int RookCheckBonus = 2;
205 const int BishopCheckBonus = 1;
206 const int KnightCheckBonus = 1;
208 // InitKingDanger[Square] contains penalties based on the position of the
209 // defending king, indexed by king's square (from white's point of view).
210 const int InitKingDanger[] = {
211 2, 0, 2, 5, 5, 2, 0, 2,
212 2, 2, 4, 8, 8, 4, 2, 2,
213 7, 10, 12, 12, 12, 12, 10, 7,
214 15, 15, 15, 15, 15, 15, 15, 15,
215 15, 15, 15, 15, 15, 15, 15, 15,
216 15, 15, 15, 15, 15, 15, 15, 15,
217 15, 15, 15, 15, 15, 15, 15, 15,
218 15, 15, 15, 15, 15, 15, 15, 15
221 // KingDangerTable[Color][attackUnits] contains the actual king danger
222 // weighted scores, indexed by color and by a calculated integer number.
223 Score KingDangerTable[2][128];
225 // TracedTerms[Color][PieceType || TracedType] contains a breakdown of the
226 // evaluation terms, used when tracing.
227 Score TracedTerms[2][16];
228 std::stringstream TraceStream;
231 PST = 8, IMBALANCE = 9, MOBILITY = 10, THREAT = 11,
232 PASSED = 12, UNSTOPPABLE = 13, SPACE = 14, TOTAL = 15
235 // Pawn and material hash tables, indexed by the current thread id.
236 // Note that they will be initialized at 0 being global variables.
237 MaterialInfoTable* MaterialTable[MAX_THREADS];
238 PawnInfoTable* PawnTable[MAX_THREADS];
240 // Function prototypes
241 template<bool HasPopCnt, bool Trace>
242 Value do_evaluate(const Position& pos, Value& margin);
244 template<Color Us, bool HasPopCnt>
245 void init_eval_info(const Position& pos, EvalInfo& ei);
247 template<Color Us, bool HasPopCnt, bool Trace>
248 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility);
250 template<Color Us, bool HasPopCnt, bool Trace>
251 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]);
254 Score evaluate_threats(const Position& pos, EvalInfo& ei);
256 template<Color Us, bool HasPopCnt>
257 int evaluate_space(const Position& pos, EvalInfo& ei);
260 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
262 template<bool HasPopCnt>
263 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
265 inline Score apply_weight(Score v, Score weight);
266 Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf);
267 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
277 /// Prefetches in pawn hash tables
279 void prefetchPawn(Key key, int threadID) {
281 PawnTable[threadID]->prefetch(key);
285 /// evaluate() is the main evaluation function. It always computes two
286 /// values, an endgame score and a middle game score, and interpolates
287 /// between them based on the remaining material.
288 Value evaluate(const Position& pos, Value& margin) {
290 return CpuHasPOPCNT ? do_evaluate<true, false>(pos, margin)
291 : do_evaluate<false, false>(pos, margin);
296 double to_cp(Value v) { return double(v) / double(PawnValueMidgame); }
298 void trace_add(int idx, Score term_w, Score term_b = Score(0)) {
300 TracedTerms[WHITE][idx] = term_w;
301 TracedTerms[BLACK][idx] = term_b;
304 template<bool HasPopCnt, bool Trace>
305 Value do_evaluate(const Position& pos, Value& margin) {
309 Score mobilityWhite, mobilityBlack;
312 assert(pos.thread() >= 0 && pos.thread() < MAX_THREADS);
313 assert(!pos.is_check());
315 // Initialize value by reading the incrementally updated scores included
316 // in the position object (material + piece square tables).
317 Score bonus = pos.value();
319 // margins[] store the uncertainty estimation of position's evaluation
320 // that typically is used by the search for pruning decisions.
321 margins[WHITE] = margins[BLACK] = VALUE_ZERO;
323 // Probe the material hash table
324 MaterialInfo* mi = MaterialTable[pos.thread()]->get_material_info(pos);
325 bonus += mi->material_value();
327 // If we have a specialized evaluation function for the current material
328 // configuration, call it and return.
329 if (mi->specialized_eval_exists())
332 return mi->evaluate(pos);
335 // Probe the pawn hash table
336 ei.pi = PawnTable[pos.thread()]->get_pawn_info(pos);
337 bonus += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
339 // Initialize attack and king safety bitboards
340 init_eval_info<WHITE, HasPopCnt>(pos, ei);
341 init_eval_info<BLACK, HasPopCnt>(pos, ei);
343 // Evaluate pieces and mobility
344 bonus += evaluate_pieces_of_color<WHITE, HasPopCnt, Trace>(pos, ei, mobilityWhite)
345 - evaluate_pieces_of_color<BLACK, HasPopCnt, Trace>(pos, ei, mobilityBlack);
347 bonus += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
349 // Evaluate kings after all other pieces because we need complete attack
350 // information when computing the king safety evaluation.
351 bonus += evaluate_king<WHITE, HasPopCnt, Trace>(pos, ei, margins)
352 - evaluate_king<BLACK, HasPopCnt, Trace>(pos, ei, margins);
354 // Evaluate tactical threats, we need full attack information including king
355 bonus += evaluate_threats<WHITE>(pos, ei)
356 - evaluate_threats<BLACK>(pos, ei);
358 // Evaluate passed pawns, we need full attack information including king
359 bonus += evaluate_passed_pawns<WHITE>(pos, ei)
360 - evaluate_passed_pawns<BLACK>(pos, ei);
362 // If one side has only a king, check whether exists any unstoppable passed pawn
363 if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
365 bonus += evaluate_unstoppable_pawns<HasPopCnt>(pos, ei);
368 trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns<HasPopCnt>(pos, ei));
371 // Evaluate space for both sides, only in middle-game.
372 if (mi->space_weight())
374 int s_w = evaluate_space<WHITE, HasPopCnt>(pos, ei);
375 int s_b = evaluate_space<BLACK, HasPopCnt>(pos, ei);
376 bonus += apply_weight(make_score((s_w - s_b) * mi->space_weight(), 0), Weights[Space]);
379 trace_add(SPACE, apply_weight(make_score(s_w * mi->space_weight(), make_score(0, 0)), Weights[Space]),
380 apply_weight(make_score(s_b * mi->space_weight(), make_score(0, 0)), Weights[Space]));
383 // Scale winning side if position is more drawish that what it appears
384 ScaleFactor sf = eg_value(bonus) > VALUE_DRAW ? mi->scale_factor(pos, WHITE)
385 : mi->scale_factor(pos, BLACK);
386 Phase phase = mi->game_phase();
388 // If we don't already have an unusual scale factor, check for opposite
389 // colored bishop endgames, and use a lower scale for those.
390 if ( phase < PHASE_MIDGAME
391 && pos.opposite_colored_bishops()
392 && sf == SCALE_FACTOR_NORMAL)
394 // Only the two bishops ?
395 if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
396 && pos.non_pawn_material(BLACK) == BishopValueMidgame)
398 // Check for KBP vs KB with only a single pawn that is almost
399 // certainly a draw or at least two pawns.
400 bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
401 sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
404 // Endgame with opposite-colored bishops, but also other pieces. Still
405 // a bit drawish, but not as drawish as with only the two bishops.
406 sf = ScaleFactor(50);
409 // Interpolate between the middle game and the endgame score
410 margin = margins[pos.side_to_move()];
411 Value v = scale_by_game_phase(bonus, phase, sf);
415 trace_add(PST, pos.value());
416 trace_add(IMBALANCE, mi->material_value());
417 trace_add(PAWN, apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]));
418 trace_add(MOBILITY, apply_weight(mobilityWhite, Weights[Mobility]), apply_weight(mobilityBlack, Weights[Mobility]));
419 trace_add(THREAT, evaluate_threats<WHITE>(pos, ei), evaluate_threats<BLACK>(pos, ei));
420 trace_add(PASSED, evaluate_passed_pawns<WHITE>(pos, ei), evaluate_passed_pawns<BLACK>(pos, ei));
421 trace_add(TOTAL, bonus);
422 TraceStream << "\nUncertainty margin: White: " << to_cp(margins[WHITE])
423 << ", Black: " << to_cp(margins[BLACK])
424 << "\nScaling: " << std::noshowpos
425 << std::setw(6) << 100.0 * phase/128.0 << "% MG, "
426 << std::setw(6) << 100.0 * (1.0 - phase/128.0) << "% * "
427 << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
428 << "Total evaluation: " << to_cp(v);
431 return pos.side_to_move() == WHITE ? v : -v;
437 /// init_eval() initializes various tables used by the evaluation function
439 void init_eval(int threads) {
441 assert(threads <= MAX_THREADS);
443 for (int i = 0; i < MAX_THREADS; i++)
448 delete MaterialTable[i];
450 MaterialTable[i] = NULL;
454 PawnTable[i] = new PawnInfoTable();
456 if (!MaterialTable[i])
457 MaterialTable[i] = new MaterialInfoTable();
462 /// quit_eval() releases heap-allocated memory at program termination
470 /// read_weights() reads evaluation weights from the corresponding UCI parameters
472 void read_evaluation_uci_options(Color us) {
474 // King safety is asymmetrical. Our king danger level is weighted by
475 // "Cowardice" UCI parameter, instead the opponent one by "Aggressiveness".
476 const int kingDangerUs = (us == WHITE ? KingDangerUs : KingDangerThem);
477 const int kingDangerThem = (us == WHITE ? KingDangerThem : KingDangerUs);
479 Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
480 Weights[PawnStructure] = weight_option("Pawn Structure (Middle Game)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
481 Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
482 Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
483 Weights[kingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
484 Weights[kingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
486 // If running in analysis mode, make sure we use symmetrical king safety. We do this
487 // by replacing both Weights[kingDangerUs] and Weights[kingDangerThem] by their average.
488 if (Options["UCI_AnalyseMode"].value<bool>())
489 Weights[kingDangerUs] = Weights[kingDangerThem] = (Weights[kingDangerUs] + Weights[kingDangerThem]) / 2;
497 // init_eval_info() initializes king bitboards for given color adding
498 // pawn attacks. To be done at the beginning of the evaluation.
500 template<Color Us, bool HasPopCnt>
501 void init_eval_info(const Position& pos, EvalInfo& ei) {
503 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
504 const Color Them = (Us == WHITE ? BLACK : WHITE);
506 Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
507 ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
509 // Init king safety tables only if we are going to use them
510 if ( pos.piece_count(Us, QUEEN)
511 && pos.non_pawn_material(Us) >= QueenValueMidgame + RookValueMidgame)
513 ei.kingZone[Us] = (b | (Us == WHITE ? b >> 8 : b << 8));
514 b &= ei.attackedBy[Us][PAWN];
515 ei.kingAttackersCount[Us] = b ? count_1s<Max15>(b) / 2 : 0;
516 ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
518 ei.kingZone[Us] = ei.kingAttackersCount[Us] = 0;
522 // evaluate_outposts() evaluates bishop and knight outposts squares
524 template<PieceType Piece, Color Us>
525 Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
527 const Color Them = (Us == WHITE ? BLACK : WHITE);
529 assert (Piece == BISHOP || Piece == KNIGHT);
531 // Initial bonus based on square
532 Value bonus = OutpostBonus[Piece == BISHOP][relative_square(Us, s)];
534 // Increase bonus if supported by pawn, especially if the opponent has
535 // no minor piece which can exchange the outpost piece.
536 if (bonus && bit_is_set(ei.attackedBy[Us][PAWN], s))
538 if ( pos.pieces(KNIGHT, Them) == EmptyBoardBB
539 && (SquaresByColorBB[square_color(s)] & pos.pieces(BISHOP, Them)) == EmptyBoardBB)
540 bonus += bonus + bonus / 2;
544 return make_score(bonus, bonus);
548 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
550 template<PieceType Piece, Color Us, bool HasPopCnt, bool Trace>
551 Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
557 Score bonus = SCORE_ZERO;
559 const BitCountType Full = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64 : CNT32;
560 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
561 const Color Them = (Us == WHITE ? BLACK : WHITE);
562 const Square* ptr = pos.piece_list_begin(Us, Piece);
564 ei.attackedBy[Us][Piece] = EmptyBoardBB;
566 while ((s = *ptr++) != SQ_NONE)
568 // Find attacked squares, including x-ray attacks for bishops and rooks
569 if (Piece == KNIGHT || Piece == QUEEN)
570 b = pos.attacks_from<Piece>(s);
571 else if (Piece == BISHOP)
572 b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
573 else if (Piece == ROOK)
574 b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
578 // Update attack info
579 ei.attackedBy[Us][Piece] |= b;
582 if (b & ei.kingZone[Us])
584 ei.kingAttackersCount[Us]++;
585 ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
586 Bitboard bb = (b & ei.attackedBy[Them][KING]);
588 ei.kingAdjacentZoneAttacksCount[Us] += count_1s<Max15>(bb);
592 mob = (Piece != QUEEN ? count_1s<Max15>(b & mobilityArea)
593 : count_1s<Full >(b & mobilityArea));
595 mobility += MobilityBonus[Piece][mob];
597 // Decrease score if we are attacked by an enemy pawn. Remaining part
598 // of threat evaluation must be done later when we have full attack info.
599 if (bit_is_set(ei.attackedBy[Them][PAWN], s))
600 bonus -= ThreatedByPawnPenalty[Piece];
602 // Bishop and knight outposts squares
603 if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Us))
604 bonus += evaluate_outposts<Piece, Us>(pos, ei, s);
606 // Queen or rook on 7th rank
607 if ( (Piece == ROOK || Piece == QUEEN)
608 && relative_rank(Us, s) == RANK_7
609 && relative_rank(Us, pos.king_square(Them)) == RANK_8)
611 bonus += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
614 // Special extra evaluation for bishops
615 if (Piece == BISHOP && pos.is_chess960())
617 // An important Chess960 pattern: A cornered bishop blocked by
618 // a friendly pawn diagonally in front of it is a very serious
619 // problem, especially when that pawn is also blocked.
620 if (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1))
622 Square d = pawn_push(Us) + (square_file(s) == FILE_A ? DELTA_E : DELTA_W);
623 if (pos.piece_on(s + d) == make_piece(Us, PAWN))
625 if (!pos.square_is_empty(s + d + pawn_push(Us)))
626 bonus -= 2*TrappedBishopA1H1Penalty;
627 else if (pos.piece_on(s + 2*d) == make_piece(Us, PAWN))
628 bonus -= TrappedBishopA1H1Penalty;
630 bonus -= TrappedBishopA1H1Penalty / 2;
635 // Special extra evaluation for rooks
638 // Open and half-open files
640 if (ei.pi->file_is_half_open(Us, f))
642 if (ei.pi->file_is_half_open(Them, f))
643 bonus += RookOpenFileBonus;
645 bonus += RookHalfOpenFileBonus;
648 // Penalize rooks which are trapped inside a king. Penalize more if
649 // king has lost right to castle.
650 if (mob > 6 || ei.pi->file_is_half_open(Us, f))
653 ksq = pos.king_square(Us);
655 if ( square_file(ksq) >= FILE_E
656 && square_file(s) > square_file(ksq)
657 && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
659 // Is there a half-open file between the king and the edge of the board?
660 if (!ei.pi->has_open_file_to_right(Us, square_file(ksq)))
661 bonus -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
662 : (TrappedRookPenalty - mob * 16), 0);
664 else if ( square_file(ksq) <= FILE_D
665 && square_file(s) < square_file(ksq)
666 && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
668 // Is there a half-open file between the king and the edge of the board?
669 if (!ei.pi->has_open_file_to_left(Us, square_file(ksq)))
670 bonus -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
671 : (TrappedRookPenalty - mob * 16), 0);
677 TracedTerms[Us][Piece] = bonus;
683 // evaluate_threats<>() assigns bonuses according to the type of attacking piece
684 // and the type of attacked one.
687 Score evaluate_threats(const Position& pos, EvalInfo& ei) {
689 const Color Them = (Us == WHITE ? BLACK : WHITE);
692 Score bonus = SCORE_ZERO;
694 // Enemy pieces not defended by a pawn and under our attack
695 Bitboard weakEnemies = pos.pieces_of_color(Them)
696 & ~ei.attackedBy[Them][PAWN]
697 & ei.attackedBy[Us][0];
701 // Add bonus according to type of attacked enemy piece and to the
702 // type of attacking piece, from knights to queens. Kings are not
703 // considered because are already handled in king evaluation.
704 for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
706 b = ei.attackedBy[Us][pt1] & weakEnemies;
708 for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
709 if (b & pos.pieces(pt2))
710 bonus += ThreatBonus[pt1][pt2];
716 // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
717 // pieces of a given color.
719 template<Color Us, bool HasPopCnt, bool Trace>
720 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) {
722 const Color Them = (Us == WHITE ? BLACK : WHITE);
724 Score bonus = mobility = SCORE_ZERO;
726 // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
727 const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces_of_color(Us));
729 bonus += evaluate_pieces<KNIGHT, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
730 bonus += evaluate_pieces<BISHOP, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
731 bonus += evaluate_pieces<ROOK, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
732 bonus += evaluate_pieces<QUEEN, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
734 // Sum up all attacked squares
735 ei.attackedBy[Us][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
736 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
737 | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
742 // evaluate_king<>() assigns bonuses and penalties to a king of a given color
744 template<Color Us, bool HasPopCnt, bool Trace>
745 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
747 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
748 const Color Them = (Us == WHITE ? BLACK : WHITE);
750 Bitboard undefended, b, b1, b2, safe;
752 const Square ksq = pos.king_square(Us);
755 Score bonus = ei.pi->king_shelter<Us>(pos, ksq);
757 // King safety. This is quite complicated, and is almost certainly far
758 // from optimally tuned.
759 if ( ei.kingAttackersCount[Them] >= 2
760 && ei.kingAdjacentZoneAttacksCount[Them])
762 // Find the attacked squares around the king which has no defenders
763 // apart from the king itself
764 undefended = ei.attackedBy[Them][0] & ei.attackedBy[Us][KING];
765 undefended &= ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
766 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
767 | ei.attackedBy[Us][QUEEN]);
769 // Initialize the 'attackUnits' variable, which is used later on as an
770 // index to the KingDangerTable[] array. The initial value is based on
771 // the number and types of the enemy's attacking pieces, the number of
772 // attacked and undefended squares around our king, the square of the
773 // king, and the quality of the pawn shelter.
774 attackUnits = Min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
775 + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + count_1s<Max15>(undefended))
776 + InitKingDanger[relative_square(Us, ksq)]
777 - mg_value(ei.pi->king_shelter<Us>(pos, ksq)) / 32;
779 // Analyse enemy's safe queen contact checks. First find undefended
780 // squares around the king attacked by enemy queen...
781 b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces_of_color(Them);
784 // ...then remove squares not supported by another enemy piece
785 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
786 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
788 attackUnits += QueenContactCheckBonus
790 * (Them == pos.side_to_move() ? 2 : 1);
793 // Analyse enemy's safe rook contact checks. First find undefended
794 // squares around the king attacked by enemy rooks...
795 b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces_of_color(Them);
797 // Consider only squares where the enemy rook gives check
798 b &= RookPseudoAttacks[ksq];
802 // ...then remove squares not supported by another enemy piece
803 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
804 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]);
806 attackUnits += RookContactCheckBonus
808 * (Them == pos.side_to_move() ? 2 : 1);
811 // Analyse enemy's safe distance checks for sliders and knights
812 safe = ~(pos.pieces_of_color(Them) | ei.attackedBy[Us][0]);
814 b1 = pos.attacks_from<ROOK>(ksq) & safe;
815 b2 = pos.attacks_from<BISHOP>(ksq) & safe;
817 // Enemy queen safe checks
818 b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
820 attackUnits += QueenCheckBonus * count_1s<Max15>(b);
822 // Enemy rooks safe checks
823 b = b1 & ei.attackedBy[Them][ROOK];
825 attackUnits += RookCheckBonus * count_1s<Max15>(b);
827 // Enemy bishops safe checks
828 b = b2 & ei.attackedBy[Them][BISHOP];
830 attackUnits += BishopCheckBonus * count_1s<Max15>(b);
832 // Enemy knights safe checks
833 b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
835 attackUnits += KnightCheckBonus * count_1s<Max15>(b);
837 // To index KingDangerTable[] attackUnits must be in [0, 99] range
838 attackUnits = Min(99, Max(0, attackUnits));
840 // Finally, extract the king danger score from the KingDangerTable[]
841 // array and subtract the score from evaluation. Set also margins[]
842 // value that will be used for pruning because this value can sometimes
843 // be very big, and so capturing a single attacking piece can therefore
844 // result in a score change far bigger than the value of the captured piece.
845 bonus -= KingDangerTable[Us][attackUnits];
846 margins[Us] += mg_value(KingDangerTable[Us][attackUnits]);
850 TracedTerms[Us][KING] = bonus;
856 // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
859 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
861 const Color Them = (Us == WHITE ? BLACK : WHITE);
863 Score bonus = SCORE_ZERO;
864 Bitboard squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
865 Bitboard b = ei.pi->passed_pawns(Us);
871 Square s = pop_1st_bit(&b);
873 assert(pos.pawn_is_passed(Us, s));
875 int r = int(relative_rank(Us, s) - RANK_2);
876 int rr = r * (r - 1);
878 // Base bonus based on rank
879 Value mbonus = Value(20 * rr);
880 Value ebonus = Value(10 * (rr + r + 1));
884 Square blockSq = s + pawn_push(Us);
886 // Adjust bonus based on kings proximity
887 ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 3 * rr);
888 ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
889 ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 6 * rr);
891 // If the pawn is free to advance, increase bonus
892 if (pos.square_is_empty(blockSq))
894 squaresToQueen = squares_in_front_of(Us, s);
895 defendedSquares = squaresToQueen & ei.attackedBy[Us][0];
897 // If there is an enemy rook or queen attacking the pawn from behind,
898 // add all X-ray attacks by the rook or queen. Otherwise consider only
899 // the squares in the pawn's path attacked or occupied by the enemy.
900 if ( (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them))
901 && (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from<ROOK>(s)))
902 unsafeSquares = squaresToQueen;
904 unsafeSquares = squaresToQueen & (ei.attackedBy[Them][0] | pos.pieces_of_color(Them));
906 // If there aren't enemy attacks or pieces along the path to queen give
907 // huge bonus. Even bigger if we protect the pawn's path.
909 ebonus += Value(rr * (squaresToQueen == defendedSquares ? 17 : 15));
911 // OK, there are enemy attacks or pieces (but not pawns). Are those
912 // squares which are attacked by the enemy also attacked by us ?
913 // If yes, big bonus (but smaller than when there are no enemy attacks),
914 // if no, somewhat smaller bonus.
915 ebonus += Value(rr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8));
917 // At last, add a small bonus when there are no *friendly* pieces
918 // in the pawn's path.
919 if (!(squaresToQueen & pos.pieces_of_color(Us)))
924 // Increase the bonus if the passed pawn is supported by a friendly pawn
925 // on the same rank and a bit smaller if it's on the previous rank.
926 supportingPawns = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
927 if (supportingPawns & rank_bb(s))
928 ebonus += Value(r * 20);
929 else if (supportingPawns & rank_bb(s - pawn_push(Us)))
930 ebonus += Value(r * 12);
932 // Rook pawns are a special case: They are sometimes worse, and
933 // sometimes better than other passed pawns. It is difficult to find
934 // good rules for determining whether they are good or bad. For now,
935 // we try the following: Increase the value for rook pawns if the
936 // other side has no pieces apart from a knight, and decrease the
937 // value if the other side has a rook or queen.
938 if (square_file(s) == FILE_A || square_file(s) == FILE_H)
940 if (pos.non_pawn_material(Them) <= KnightValueMidgame)
941 ebonus += ebonus / 4;
942 else if (pos.pieces(ROOK, QUEEN, Them))
943 ebonus -= ebonus / 4;
945 bonus += make_score(mbonus, ebonus);
949 // Add the scores to the middle game and endgame eval
950 return apply_weight(bonus, Weights[PassedPawns]);
953 // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides
954 template<bool HasPopCnt>
955 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
957 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
959 // Step 1. Hunt for unstoppable pawns. If we find at least one, record how many plies
960 // are required for promotion
961 int pliesToGo[2] = {256, 256};
963 for (Color c = WHITE; c <= BLACK; c++)
965 // Skip if other side has non-pawn pieces
966 if (pos.non_pawn_material(opposite_color(c)))
969 Bitboard b = ei.pi->passed_pawns(c);
973 Square s = pop_1st_bit(&b);
974 Square queeningSquare = relative_square(c, make_square(square_file(s), RANK_8));
976 int mtg = RANK_8 - relative_rank(c, s) - int(relative_rank(c, s) == RANK_2);
977 int oppmtg = square_distance(pos.king_square(opposite_color(c)), queeningSquare) - int(c != pos.side_to_move());
978 bool pathDefended = ((ei.attackedBy[c][0] & squares_in_front_of(c, s)) == squares_in_front_of(c, s));
980 if (mtg >= oppmtg && !pathDefended)
983 int blockerCount = count_1s<Max15>(squares_in_front_of(c, s) & pos.occupied_squares());
986 if (mtg >= oppmtg && !pathDefended)
989 int ptg = 2 * mtg - int(c == pos.side_to_move());
991 if (ptg < pliesToGo[c])
996 // Step 2. If either side cannot promote at least three plies before the other side then
997 // situation becomes too complex and we give up. Otherwise we determine the possibly "winning side"
998 if (abs(pliesToGo[WHITE] - pliesToGo[BLACK]) < 3)
999 return make_score(0, 0);
1001 Color winnerSide = (pliesToGo[WHITE] < pliesToGo[BLACK] ? WHITE : BLACK);
1002 Color loserSide = opposite_color(winnerSide);
1004 // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
1005 // We collect the potential candidates in potentialBB.
1006 Bitboard pawnBB = pos.pieces(PAWN, loserSide);
1007 Bitboard potentialBB = pawnBB;
1008 const Bitboard passedBB = ei.pi->passed_pawns(loserSide);
1012 Square psq = pop_1st_bit(&pawnBB);
1014 // Check direct advancement
1015 int mtg = RANK_8 - relative_rank(loserSide, psq) - int(relative_rank(loserSide, psq) == RANK_2);
1016 int ptg = 2 * mtg - int(loserSide == pos.side_to_move());
1018 // Check if (without even considering any obstacles) we're too far away
1019 if (pliesToGo[winnerSide] + 3 <= ptg)
1021 clear_bit(&potentialBB, psq);
1025 // If this is passed pawn, then it _may_ promote in time. We give up.
1026 if (bit_is_set(passedBB, psq))
1027 return make_score(0, 0);
1029 // Doubled pawn is worthless
1030 if (squares_in_front_of(loserSide, psq) & (pos.pieces(PAWN, loserSide)))
1032 clear_bit(&potentialBB, psq);
1037 // Step 4. Check new passed pawn creation through king capturing and sacrifises
1038 pawnBB = potentialBB;
1042 Square psq = pop_1st_bit(&pawnBB);
1044 int mtg = RANK_8 - relative_rank(loserSide, psq) - int(relative_rank(loserSide, psq) == RANK_2);
1045 int ptg = 2 * mtg - int(loserSide == pos.side_to_move());
1047 // Generate list of obstacles
1048 Bitboard obsBB = passed_pawn_mask(loserSide, psq) & pos.pieces(PAWN, winnerSide);
1049 const bool pawnIsOpposed = squares_in_front_of(loserSide, psq) & obsBB;
1052 // How many plies does it take to remove all the obstacles?
1054 int realObsCount = 0;
1055 int minKingDist = 256;
1059 Square obSq = pop_1st_bit(&obsBB);
1062 // Check pawns that can give support to overcome obstacle (Eg. wp: a4,b4 bp: b2. b4 is giving support)
1063 if (!pawnIsOpposed && square_file(psq) != square_file(obSq))
1065 Bitboard supBB = in_front_bb(winnerSide, Square(obSq + (winnerSide == WHITE ? 8 : -8)))
1066 & neighboring_files_bb(psq) & potentialBB;
1068 while(supBB) // This while-loop could be replaced with supSq = LSB/MSB(supBB) (depending on color)
1070 Square supSq = pop_1st_bit(&supBB);
1071 int dist = square_distance(obSq, supSq);
1072 minMoves = Min(minMoves, dist - 2);
1077 // Check pawns that can be sacrifised
1078 Bitboard sacBB = passed_pawn_mask(winnerSide, obSq) & neighboring_files_bb(obSq) & potentialBB & ~(1ULL << psq);
1080 while(sacBB) // This while-loop could be replaced with sacSq = LSB/MSB(sacBB) (depending on color)
1082 Square sacSq = pop_1st_bit(&sacBB);
1083 int dist = square_distance(obSq, sacSq);
1084 minMoves = Min(minMoves, dist - 2);
1087 // If obstacle can be destroyed with immediate pawn sacrifise, it's not real obstacle
1091 // Pawn sac calculations
1092 sacptg += minMoves * 2;
1094 // King capture calc
1096 int kingDist = square_distance(pos.king_square(loserSide), obSq);
1097 minKingDist = Min(minKingDist, kingDist);
1100 // Check if pawn sac plan _may_ save the day
1101 if (pliesToGo[winnerSide] + 3 > ptg + sacptg)
1102 return make_score(0, 0);
1104 // Check if king capture plan _may_ save the day (contains some false positives)
1105 int kingptg = (minKingDist + realObsCount) * 2;
1106 if (pliesToGo[winnerSide] + 3 > ptg + kingptg)
1107 return make_score(0, 0);
1110 // Step 5. Assign bonus
1111 const int Sign[2] = {1, -1};
1112 return Sign[winnerSide] * make_score(0, (Value) 0x500 - 0x20 * pliesToGo[winnerSide]);
1116 // evaluate_space() computes the space evaluation for a given side. The
1117 // space evaluation is a simple bonus based on the number of safe squares
1118 // available for minor pieces on the central four files on ranks 2--4. Safe
1119 // squares one, two or three squares behind a friendly pawn are counted
1120 // twice. Finally, the space bonus is scaled by a weight taken from the
1121 // material hash table. The aim is to improve play on game opening.
1122 template<Color Us, bool HasPopCnt>
1123 int evaluate_space(const Position& pos, EvalInfo& ei) {
1125 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
1126 const Color Them = (Us == WHITE ? BLACK : WHITE);
1128 // Find the safe squares for our pieces inside the area defined by
1129 // SpaceMask[]. A square is unsafe if it is attacked by an enemy
1130 // pawn, or if it is undefended and attacked by an enemy piece.
1131 Bitboard safe = SpaceMask[Us]
1132 & ~pos.pieces(PAWN, Us)
1133 & ~ei.attackedBy[Them][PAWN]
1134 & (ei.attackedBy[Us][0] | ~ei.attackedBy[Them][0]);
1136 // Find all squares which are at most three squares behind some friendly pawn
1137 Bitboard behind = pos.pieces(PAWN, Us);
1138 behind |= (Us == WHITE ? behind >> 8 : behind << 8);
1139 behind |= (Us == WHITE ? behind >> 16 : behind << 16);
1141 return count_1s<Max15>(safe) + count_1s<Max15>(behind & safe);
1145 // apply_weight() applies an evaluation weight to a value trying to prevent overflow
1147 inline Score apply_weight(Score v, Score w) {
1148 return make_score((int(mg_value(v)) * mg_value(w)) / 0x100,
1149 (int(eg_value(v)) * eg_value(w)) / 0x100);
1153 // scale_by_game_phase() interpolates between a middle game and an endgame score,
1154 // based on game phase. It also scales the return value by a ScaleFactor array.
1156 Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf) {
1158 assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
1159 assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
1160 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1162 Value eg = eg_value(v);
1163 Value ev = Value((eg * int(sf)) / SCALE_FACTOR_NORMAL);
1165 int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128;
1166 return Value((result + GrainSize / 2) & ~(GrainSize - 1));
1170 // weight_option() computes the value of an evaluation weight, by combining
1171 // two UCI-configurable weights (midgame and endgame) with an internal weight.
1173 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
1175 // Scale option value from 100 to 256
1176 int mg = Options[mgOpt].value<int>() * 256 / 100;
1177 int eg = Options[egOpt].value<int>() * 256 / 100;
1179 return apply_weight(make_score(mg, eg), internalWeight);
1183 // init_safety() initizes the king safety evaluation, based on UCI
1184 // parameters. It is called from read_weights().
1186 void init_safety() {
1188 const Value MaxSlope = Value(30);
1189 const Value Peak = Value(1280);
1192 // First setup the base table
1193 for (int i = 0; i < 100; i++)
1195 t[i] = Value(int(0.4 * i * i));
1198 t[i] = Min(t[i], t[i - 1] + MaxSlope);
1200 t[i] = Min(t[i], Peak);
1203 // Then apply the weights and get the final KingDangerTable[] array
1204 for (Color c = WHITE; c <= BLACK; c++)
1205 for (int i = 0; i < 100; i++)
1206 KingDangerTable[c][i] = apply_weight(make_score(t[i], 0), Weights[KingDangerUs + c]);
1210 // trace_row() is an helper function used by tracing code to register the
1211 // values of a single evaluation term.
1213 void trace_row(const char *name, int idx) {
1215 Score term_w = TracedTerms[WHITE][idx];
1216 Score term_b = TracedTerms[BLACK][idx];
1219 case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL:
1220 TraceStream << std::setw(20) << name << " | --- --- | --- --- | "
1221 << std::setw(6) << to_cp(mg_value(term_w)) << " "
1222 << std::setw(6) << to_cp(eg_value(term_w)) << " \n";
1225 TraceStream << std::setw(20) << name << " | " << std::noshowpos
1226 << std::setw(5) << to_cp(mg_value(term_w)) << " "
1227 << std::setw(5) << to_cp(eg_value(term_w)) << " | "
1228 << std::setw(5) << to_cp(mg_value(term_b)) << " "
1229 << std::setw(5) << to_cp(eg_value(term_b)) << " | "
1231 << std::setw(6) << to_cp(mg_value(term_w - term_b)) << " "
1232 << std::setw(6) << to_cp(eg_value(term_w - term_b)) << " \n";
1238 /// trace_evaluate() is like evaluate() but instead of a value returns a string
1239 /// suitable to be print on stdout with the detailed descriptions and values of
1240 /// each evaluation term. Used mainly for debugging.
1242 std::string trace_evaluate(const Position& pos) {
1247 TraceStream.str("");
1248 TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
1249 memset(TracedTerms, 0, 2 * 16 * sizeof(Score));
1251 do_evaluate<false, true>(pos, margin);
1253 totals = TraceStream.str();
1254 TraceStream.str("");
1256 TraceStream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
1257 << " | MG EG | MG EG | MG EG \n"
1258 << "---------------------+-------------+-------------+---------------\n";
1260 trace_row("Material, PST, Tempo", PST);
1261 trace_row("Material imbalance", IMBALANCE);
1262 trace_row("Pawns", PAWN);
1263 trace_row("Knights", KNIGHT);
1264 trace_row("Bishops", BISHOP);
1265 trace_row("Rooks", ROOK);
1266 trace_row("Queens", QUEEN);
1267 trace_row("Mobility", MOBILITY);
1268 trace_row("King safety", KING);
1269 trace_row("Threats", THREAT);
1270 trace_row("Passed pawns", PASSED);
1271 trace_row("Unstoppable pawns", UNSTOPPABLE);
1272 trace_row("Space", SPACE);
1274 TraceStream << "---------------------+-------------+-------------+---------------\n";
1275 trace_row("Total", TOTAL);
1276 TraceStream << totals;
1278 return TraceStream.str();