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/>.
31 #include "ucioption.h"
35 // Struct EvalInfo contains various information computed and collected
36 // by the evaluation functions.
39 // Pointers to material and pawn hash table entries
43 // attackedBy[color][piece type] is a bitboard representing all squares
44 // attacked by a given color and piece type, attackedBy[color][0] contains
45 // all squares attacked by the given color.
46 Bitboard attackedBy[2][8];
48 // kingRing[color] is the zone around the king which is considered
49 // by the king safety evaluation. This consists of the squares directly
50 // adjacent to the king, and the three (or two, for a king on an edge file)
51 // squares two ranks in front of the king. For instance, if black's king
52 // is on g8, kingRing[BLACK] is a bitboard containing the squares f8, h8,
53 // f7, g7, h7, f6, g6 and h6.
56 // kingAttackersCount[color] is the number of pieces of the given color
57 // which attack a square in the kingRing of the enemy king.
58 int kingAttackersCount[2];
60 // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
61 // given color which attack a square in the kingRing of the enemy king. The
62 // weights of the individual piece types are given by the variables
63 // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
64 // KnightAttackWeight in evaluate.cpp
65 int kingAttackersWeight[2];
67 // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
68 // directly adjacent to the king of the given color. Pieces which attack
69 // more than one square are counted multiple times. For instance, if black's
70 // king is on g8 and there's a white knight on g5, this knight adds
71 // 2 to kingAdjacentZoneAttacksCount[BLACK].
72 int kingAdjacentZoneAttacksCount[2];
75 // Evaluation grain size, must be a power of 2
76 const int GrainSize = 8;
78 // Evaluation weights, initialized from UCI options
79 enum { Mobility, PassedPawns, Space, KingDangerUs, KingDangerThem };
83 #define S(mg, eg) make_score(mg, eg)
85 // Internal evaluation weights. These are applied on top of the evaluation
86 // weights read from UCI parameters. The purpose is to be able to change
87 // the evaluation weights while keeping the default values of the UCI
88 // parameters at 100, which looks prettier.
90 // Values modified by Joona Kiiski
91 const Score WeightsInternal[] = {
92 S(252, 344), S(252, 259), S(46, 0), S(247, 0), S(259, 0)
95 // MobilityBonus[PieceType][attacked] contains mobility bonuses for middle and
96 // end game, indexed by piece type and number of attacked squares not occupied
97 // by friendly pieces.
98 const Score MobilityBonus[][32] = {
100 { S(-38,-33), S(-25,-23), S(-12,-13), S( 0, -3), S(12, 7), S(25, 17), // Knights
101 S( 31, 22), S( 38, 27), S( 38, 27) },
102 { S(-25,-30), S(-11,-16), S( 3, -2), S(17, 12), S(31, 26), S(45, 40), // Bishops
103 S( 57, 52), S( 65, 60), S( 71, 65), S(74, 69), S(76, 71), S(78, 73),
104 S( 79, 74), S( 80, 75), S( 81, 76), S(81, 76) },
105 { S(-20,-36), S(-14,-19), S( -8, -3), S(-2, 13), S( 4, 29), S(10, 46), // Rooks
106 S( 14, 62), S( 19, 79), S( 23, 95), S(26,106), S(27,111), S(28,114),
107 S( 29,116), S( 30,117), S( 31,118), S(32,118) },
108 { S(-10,-18), S( -8,-13), S( -6, -7), S(-3, -2), S(-1, 3), S( 1, 8), // Queens
109 S( 3, 13), S( 5, 19), S( 8, 23), S(10, 27), S(12, 32), S(15, 34),
110 S( 16, 35), S( 17, 35), S( 18, 35), S(20, 35), S(20, 35), S(20, 35),
111 S( 20, 35), S( 20, 35), S( 20, 35), S(20, 35), S(20, 35), S(20, 35),
112 S( 20, 35), S( 20, 35), S( 20, 35), S(20, 35), S(20, 35), S(20, 35),
113 S( 20, 35), S( 20, 35) }
116 // OutpostBonus[PieceType][Square] contains outpost bonuses of knights and
117 // bishops, indexed by piece type and square (from white's point of view).
118 const Value OutpostBonus[][64] = {
121 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Knights
122 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
123 V(0), V(0), V(4), V(8), V(8), V(4), V(0), V(0),
124 V(0), V(4),V(17),V(26),V(26),V(17), V(4), V(0),
125 V(0), V(8),V(26),V(35),V(35),V(26), V(8), V(0),
126 V(0), V(4),V(17),V(17),V(17),V(17), V(4), V(0) },
128 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Bishops
129 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
130 V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0),
131 V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0),
132 V(0),V(10),V(21),V(21),V(21),V(21),V(10), V(0),
133 V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0) }
136 // ThreatBonus[attacking][attacked] contains threat bonuses according to
137 // which piece type attacks which one.
138 const Score ThreatBonus[][8] = {
140 { S(0, 0), S( 7, 39), S( 0, 0), S(24, 49), S(41,100), S(41,100) }, // KNIGHT
141 { S(0, 0), S( 7, 39), S(24, 49), S( 0, 0), S(41,100), S(41,100) }, // BISHOP
142 { S(0, 0), S(-1, 29), S(15, 49), S(15, 49), S( 0, 0), S(24, 49) }, // ROOK
143 { S(0, 0), S(15, 39), S(15, 39), S(15, 39), S(15, 39), S( 0, 0) } // QUEEN
146 // ThreatenedByPawnPenalty[PieceType] contains a penalty according to which
147 // piece type is attacked by an enemy pawn.
148 const Score ThreatenedByPawnPenalty[] = {
149 S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
154 // Rooks and queens on the 7th rank (modified by Joona Kiiski)
155 const Score RookOn7thBonus = make_score(47, 98);
156 const Score QueenOn7thBonus = make_score(27, 54);
158 // Rooks on open files (modified by Joona Kiiski)
159 const Score RookOpenFileBonus = make_score(43, 43);
160 const Score RookHalfOpenFileBonus = make_score(19, 19);
162 // Penalty for rooks trapped inside a friendly king which has lost the
164 const Value TrappedRookPenalty = Value(180);
166 // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
167 // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
168 // happen in Chess960 games.
169 const Score TrappedBishopA1H1Penalty = make_score(100, 100);
171 // The SpaceMask[Color] contains the area of the board which is considered
172 // by the space evaluation. In the middle game, each side is given a bonus
173 // based on how many squares inside this area are safe and available for
174 // friendly minor pieces.
175 const Bitboard SpaceMask[] = {
176 (1ULL << SQ_C2) | (1ULL << SQ_D2) | (1ULL << SQ_E2) | (1ULL << SQ_F2) |
177 (1ULL << SQ_C3) | (1ULL << SQ_D3) | (1ULL << SQ_E3) | (1ULL << SQ_F3) |
178 (1ULL << SQ_C4) | (1ULL << SQ_D4) | (1ULL << SQ_E4) | (1ULL << SQ_F4),
179 (1ULL << SQ_C7) | (1ULL << SQ_D7) | (1ULL << SQ_E7) | (1ULL << SQ_F7) |
180 (1ULL << SQ_C6) | (1ULL << SQ_D6) | (1ULL << SQ_E6) | (1ULL << SQ_F6) |
181 (1ULL << SQ_C5) | (1ULL << SQ_D5) | (1ULL << SQ_E5) | (1ULL << SQ_F5)
184 // King danger constants and variables. The king danger scores are taken
185 // from the KingDangerTable[]. Various little "meta-bonuses" measuring
186 // the strength of the enemy attack are added up into an integer, which
187 // is used as an index to KingDangerTable[].
189 // KingAttackWeights[PieceType] contains king attack weights by piece type
190 const int KingAttackWeights[] = { 0, 0, 2, 2, 3, 5 };
192 // Bonuses for enemy's safe checks
193 const int QueenContactCheckBonus = 6;
194 const int RookContactCheckBonus = 4;
195 const int QueenCheckBonus = 3;
196 const int RookCheckBonus = 2;
197 const int BishopCheckBonus = 1;
198 const int KnightCheckBonus = 1;
200 // InitKingDanger[Square] contains penalties based on the position of the
201 // defending king, indexed by king's square (from white's point of view).
202 const int InitKingDanger[] = {
203 2, 0, 2, 5, 5, 2, 0, 2,
204 2, 2, 4, 8, 8, 4, 2, 2,
205 7, 10, 12, 12, 12, 12, 10, 7,
206 15, 15, 15, 15, 15, 15, 15, 15,
207 15, 15, 15, 15, 15, 15, 15, 15,
208 15, 15, 15, 15, 15, 15, 15, 15,
209 15, 15, 15, 15, 15, 15, 15, 15,
210 15, 15, 15, 15, 15, 15, 15, 15
213 // KingDangerTable[Color][attackUnits] contains the actual king danger
214 // weighted scores, indexed by color and by a calculated integer number.
215 Score KingDangerTable[2][128];
217 // TracedTerms[Color][PieceType || TracedType] contains a breakdown of the
218 // evaluation terms, used when tracing.
219 Score TracedScores[2][16];
220 std::stringstream TraceStream;
223 PST = 8, IMBALANCE = 9, MOBILITY = 10, THREAT = 11,
224 PASSED = 12, UNSTOPPABLE = 13, SPACE = 14, TOTAL = 15
227 // Function prototypes
228 template<bool HasPopCnt, bool Trace>
229 Value do_evaluate(const Position& pos, Value& margin);
231 template<Color Us, bool HasPopCnt>
232 void init_eval_info(const Position& pos, EvalInfo& ei);
234 template<Color Us, bool HasPopCnt, bool Trace>
235 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility);
237 template<Color Us, bool HasPopCnt, bool Trace>
238 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]);
241 Score evaluate_threats(const Position& pos, EvalInfo& ei);
243 template<Color Us, bool HasPopCnt>
244 int evaluate_space(const Position& pos, EvalInfo& ei);
247 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
249 template<bool HasPopCnt>
250 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
252 inline Score apply_weight(Score v, Score weight);
253 Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf);
254 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
256 double to_cp(Value v);
257 void trace_add(int idx, Score term_w, Score term_b = SCORE_ZERO);
261 /// evaluate() is the main evaluation function. It always computes two
262 /// values, an endgame score and a middle game score, and interpolates
263 /// between them based on the remaining material.
264 Value evaluate(const Position& pos, Value& margin) {
266 return CpuHasPOPCNT ? do_evaluate<true, false>(pos, margin)
267 : do_evaluate<false, false>(pos, margin);
272 template<bool HasPopCnt, bool Trace>
273 Value do_evaluate(const Position& pos, Value& margin) {
277 Score score, mobilityWhite, mobilityBlack;
279 assert(pos.thread() >= 0 && pos.thread() < MAX_THREADS);
280 assert(!pos.in_check());
282 // Initialize score by reading the incrementally updated scores included
283 // in the position object (material + piece square tables).
286 // margins[] store the uncertainty estimation of position's evaluation
287 // that typically is used by the search for pruning decisions.
288 margins[WHITE] = margins[BLACK] = VALUE_ZERO;
290 // Probe the material hash table
291 ei.mi = Threads[pos.thread()].materialTable.get_material_info(pos);
292 score += ei.mi->material_value();
294 // If we have a specialized evaluation function for the current material
295 // configuration, call it and return.
296 if (ei.mi->specialized_eval_exists())
299 return ei.mi->evaluate(pos);
302 // Probe the pawn hash table
303 ei.pi = Threads[pos.thread()].pawnTable.get_pawn_info(pos);
304 score += ei.pi->pawns_value();
306 // Initialize attack and king safety bitboards
307 init_eval_info<WHITE, HasPopCnt>(pos, ei);
308 init_eval_info<BLACK, HasPopCnt>(pos, ei);
310 // Evaluate pieces and mobility
311 score += evaluate_pieces_of_color<WHITE, HasPopCnt, Trace>(pos, ei, mobilityWhite)
312 - evaluate_pieces_of_color<BLACK, HasPopCnt, Trace>(pos, ei, mobilityBlack);
314 score += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
316 // Evaluate kings after all other pieces because we need complete attack
317 // information when computing the king safety evaluation.
318 score += evaluate_king<WHITE, HasPopCnt, Trace>(pos, ei, margins)
319 - evaluate_king<BLACK, HasPopCnt, Trace>(pos, ei, margins);
321 // Evaluate tactical threats, we need full attack information including king
322 score += evaluate_threats<WHITE>(pos, ei)
323 - evaluate_threats<BLACK>(pos, ei);
325 // Evaluate passed pawns, we need full attack information including king
326 score += evaluate_passed_pawns<WHITE>(pos, ei)
327 - evaluate_passed_pawns<BLACK>(pos, ei);
329 // If one side has only a king, check whether exists any unstoppable passed pawn
330 if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
331 score += evaluate_unstoppable_pawns<HasPopCnt>(pos, ei);
333 // Evaluate space for both sides, only in middle-game.
334 if (ei.mi->space_weight())
336 int s = evaluate_space<WHITE, HasPopCnt>(pos, ei) - evaluate_space<BLACK, HasPopCnt>(pos, ei);
337 score += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]);
340 // Scale winning side if position is more drawish that what it appears
341 ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE)
342 : ei.mi->scale_factor(pos, BLACK);
344 // If we don't already have an unusual scale factor, check for opposite
345 // colored bishop endgames, and use a lower scale for those.
346 if ( ei.mi->game_phase() < PHASE_MIDGAME
347 && pos.opposite_colored_bishops()
348 && sf == SCALE_FACTOR_NORMAL)
350 // Only the two bishops ?
351 if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
352 && pos.non_pawn_material(BLACK) == BishopValueMidgame)
354 // Check for KBP vs KB with only a single pawn that is almost
355 // certainly a draw or at least two pawns.
356 bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
357 sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
360 // Endgame with opposite-colored bishops, but also other pieces. Still
361 // a bit drawish, but not as drawish as with only the two bishops.
362 sf = ScaleFactor(50);
365 // Interpolate between the middle game and the endgame score
366 margin = margins[pos.side_to_move()];
367 Value v = scale_by_game_phase(score, ei.mi->game_phase(), sf);
369 // In case of tracing add all single evaluation contributions for both white and black
372 trace_add(PST, pos.value());
373 trace_add(IMBALANCE, ei.mi->material_value());
374 trace_add(PAWN, ei.pi->pawns_value());
375 trace_add(MOBILITY, apply_weight(mobilityWhite, Weights[Mobility]), apply_weight(mobilityBlack, Weights[Mobility]));
376 trace_add(THREAT, evaluate_threats<WHITE>(pos, ei), evaluate_threats<BLACK>(pos, ei));
377 trace_add(PASSED, evaluate_passed_pawns<WHITE>(pos, ei), evaluate_passed_pawns<BLACK>(pos, ei));
378 trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns<false>(pos, ei));
379 Score w = make_score(ei.mi->space_weight() * evaluate_space<WHITE, false>(pos, ei), 0);
380 Score b = make_score(ei.mi->space_weight() * evaluate_space<BLACK, false>(pos, ei), 0);
381 trace_add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
382 trace_add(TOTAL, score);
383 TraceStream << "\nUncertainty margin: White: " << to_cp(margins[WHITE])
384 << ", Black: " << to_cp(margins[BLACK])
385 << "\nScaling: " << std::noshowpos
386 << std::setw(6) << 100.0 * ei.mi->game_phase() / 128.0 << "% MG, "
387 << std::setw(6) << 100.0 * (1.0 - ei.mi->game_phase() / 128.0) << "% * "
388 << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
389 << "Total evaluation: " << to_cp(v);
392 return pos.side_to_move() == WHITE ? v : -v;
398 /// read_weights() reads evaluation weights from the corresponding UCI parameters
400 void read_evaluation_uci_options(Color us) {
402 // King safety is asymmetrical. Our king danger level is weighted by
403 // "Cowardice" UCI parameter, instead the opponent one by "Aggressiveness".
404 const int kingDangerUs = (us == WHITE ? KingDangerUs : KingDangerThem);
405 const int kingDangerThem = (us == WHITE ? KingDangerThem : KingDangerUs);
407 Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
408 Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
409 Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
410 Weights[kingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
411 Weights[kingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
413 // If running in analysis mode, make sure we use symmetrical king safety. We do this
414 // by replacing both Weights[kingDangerUs] and Weights[kingDangerThem] by their average.
415 if (Options["UCI_AnalyseMode"].value<bool>())
416 Weights[kingDangerUs] = Weights[kingDangerThem] = (Weights[kingDangerUs] + Weights[kingDangerThem]) / 2;
424 // init_eval_info() initializes king bitboards for given color adding
425 // pawn attacks. To be done at the beginning of the evaluation.
427 template<Color Us, bool HasPopCnt>
428 void init_eval_info(const Position& pos, EvalInfo& ei) {
430 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
431 const Color Them = (Us == WHITE ? BLACK : WHITE);
433 Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
434 ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
436 // Init king safety tables only if we are going to use them
437 if ( pos.piece_count(Us, QUEEN)
438 && pos.non_pawn_material(Us) >= QueenValueMidgame + RookValueMidgame)
440 ei.kingRing[Them] = (b | (Us == WHITE ? b >> 8 : b << 8));
441 b &= ei.attackedBy[Us][PAWN];
442 ei.kingAttackersCount[Us] = b ? count_1s<Max15>(b) / 2 : 0;
443 ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
445 ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0;
449 // evaluate_outposts() evaluates bishop and knight outposts squares
451 template<PieceType Piece, Color Us>
452 Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
454 const Color Them = (Us == WHITE ? BLACK : WHITE);
456 assert (Piece == BISHOP || Piece == KNIGHT);
458 // Initial bonus based on square
459 Value bonus = OutpostBonus[Piece == BISHOP][relative_square(Us, s)];
461 // Increase bonus if supported by pawn, especially if the opponent has
462 // no minor piece which can exchange the outpost piece.
463 if (bonus && bit_is_set(ei.attackedBy[Us][PAWN], s))
465 if ( pos.pieces(KNIGHT, Them) == EmptyBoardBB
466 && (SquaresByColorBB[color_of(s)] & pos.pieces(BISHOP, Them)) == EmptyBoardBB)
467 bonus += bonus + bonus / 2;
471 return make_score(bonus, bonus);
475 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
477 template<PieceType Piece, Color Us, bool HasPopCnt, bool Trace>
478 Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
484 Score score = SCORE_ZERO;
486 const BitCountType Full = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64 : CNT32;
487 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
488 const Color Them = (Us == WHITE ? BLACK : WHITE);
489 const Square* pl = pos.piece_list(Us, Piece);
491 ei.attackedBy[Us][Piece] = EmptyBoardBB;
493 while ((s = *pl++) != SQ_NONE)
495 // Find attacked squares, including x-ray attacks for bishops and rooks
496 if (Piece == KNIGHT || Piece == QUEEN)
497 b = pos.attacks_from<Piece>(s);
498 else if (Piece == BISHOP)
499 b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
500 else if (Piece == ROOK)
501 b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
505 // Update attack info
506 ei.attackedBy[Us][Piece] |= b;
509 if (b & ei.kingRing[Them])
511 ei.kingAttackersCount[Us]++;
512 ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
513 Bitboard bb = (b & ei.attackedBy[Them][KING]);
515 ei.kingAdjacentZoneAttacksCount[Us] += count_1s<Max15>(bb);
519 mob = (Piece != QUEEN ? count_1s<Max15>(b & mobilityArea)
520 : count_1s<Full >(b & mobilityArea));
522 mobility += MobilityBonus[Piece][mob];
524 // Decrease score if we are attacked by an enemy pawn. Remaining part
525 // of threat evaluation must be done later when we have full attack info.
526 if (bit_is_set(ei.attackedBy[Them][PAWN], s))
527 score -= ThreatenedByPawnPenalty[Piece];
529 // Bishop and knight outposts squares
530 if ( (Piece == BISHOP || Piece == KNIGHT)
531 && !(pos.pieces(PAWN, Them) & attack_span_mask(Us, s)))
532 score += evaluate_outposts<Piece, Us>(pos, ei, s);
534 // Queen or rook on 7th rank
535 if ( (Piece == ROOK || Piece == QUEEN)
536 && relative_rank(Us, s) == RANK_7
537 && relative_rank(Us, pos.king_square(Them)) == RANK_8)
539 score += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
542 // Special extra evaluation for bishops
543 if (Piece == BISHOP && pos.is_chess960())
545 // An important Chess960 pattern: A cornered bishop blocked by
546 // a friendly pawn diagonally in front of it is a very serious
547 // problem, especially when that pawn is also blocked.
548 if (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1))
550 Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
551 if (pos.piece_on(s + d) == make_piece(Us, PAWN))
553 if (!pos.square_is_empty(s + d + pawn_push(Us)))
554 score -= 2*TrappedBishopA1H1Penalty;
555 else if (pos.piece_on(s + 2*d) == make_piece(Us, PAWN))
556 score -= TrappedBishopA1H1Penalty;
558 score -= TrappedBishopA1H1Penalty / 2;
563 // Special extra evaluation for rooks
566 // Open and half-open files
568 if (ei.pi->file_is_half_open(Us, f))
570 if (ei.pi->file_is_half_open(Them, f))
571 score += RookOpenFileBonus;
573 score += RookHalfOpenFileBonus;
576 // Penalize rooks which are trapped inside a king. Penalize more if
577 // king has lost right to castle.
578 if (mob > 6 || ei.pi->file_is_half_open(Us, f))
581 ksq = pos.king_square(Us);
583 if ( file_of(ksq) >= FILE_E
584 && file_of(s) > file_of(ksq)
585 && (relative_rank(Us, ksq) == RANK_1 || rank_of(ksq) == rank_of(s)))
587 // Is there a half-open file between the king and the edge of the board?
588 if (!ei.pi->has_open_file_to_right(Us, file_of(ksq)))
589 score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
590 : (TrappedRookPenalty - mob * 16), 0);
592 else if ( file_of(ksq) <= FILE_D
593 && file_of(s) < file_of(ksq)
594 && (relative_rank(Us, ksq) == RANK_1 || rank_of(ksq) == rank_of(s)))
596 // Is there a half-open file between the king and the edge of the board?
597 if (!ei.pi->has_open_file_to_left(Us, file_of(ksq)))
598 score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
599 : (TrappedRookPenalty - mob * 16), 0);
605 TracedScores[Us][Piece] = score;
611 // evaluate_threats<>() assigns bonuses according to the type of attacking piece
612 // and the type of attacked one.
615 Score evaluate_threats(const Position& pos, EvalInfo& ei) {
617 const Color Them = (Us == WHITE ? BLACK : WHITE);
620 Score score = SCORE_ZERO;
622 // Enemy pieces not defended by a pawn and under our attack
623 Bitboard weakEnemies = pos.pieces(Them)
624 & ~ei.attackedBy[Them][PAWN]
625 & ei.attackedBy[Us][0];
629 // Add bonus according to type of attacked enemy piece and to the
630 // type of attacking piece, from knights to queens. Kings are not
631 // considered because are already handled in king evaluation.
632 for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
634 b = ei.attackedBy[Us][pt1] & weakEnemies;
636 for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
637 if (b & pos.pieces(pt2))
638 score += ThreatBonus[pt1][pt2];
644 // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
645 // pieces of a given color.
647 template<Color Us, bool HasPopCnt, bool Trace>
648 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) {
650 const Color Them = (Us == WHITE ? BLACK : WHITE);
652 Score score = mobility = SCORE_ZERO;
654 // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
655 const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces(Us));
657 score += evaluate_pieces<KNIGHT, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
658 score += evaluate_pieces<BISHOP, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
659 score += evaluate_pieces<ROOK, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
660 score += evaluate_pieces<QUEEN, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
662 // Sum up all attacked squares
663 ei.attackedBy[Us][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
664 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
665 | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
670 // evaluate_king<>() assigns bonuses and penalties to a king of a given color
672 template<Color Us, bool HasPopCnt, bool Trace>
673 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
675 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
676 const Color Them = (Us == WHITE ? BLACK : WHITE);
678 Bitboard undefended, b, b1, b2, safe;
680 const Square ksq = pos.king_square(Us);
683 Score score = ei.pi->king_shelter<Us>(pos, ksq);
685 // King safety. This is quite complicated, and is almost certainly far
686 // from optimally tuned.
687 if ( ei.kingAttackersCount[Them] >= 2
688 && ei.kingAdjacentZoneAttacksCount[Them])
690 // Find the attacked squares around the king which has no defenders
691 // apart from the king itself
692 undefended = ei.attackedBy[Them][0] & ei.attackedBy[Us][KING];
693 undefended &= ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
694 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
695 | ei.attackedBy[Us][QUEEN]);
697 // Initialize the 'attackUnits' variable, which is used later on as an
698 // index to the KingDangerTable[] array. The initial value is based on
699 // the number and types of the enemy's attacking pieces, the number of
700 // attacked and undefended squares around our king, the square of the
701 // king, and the quality of the pawn shelter.
702 attackUnits = std::min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
703 + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + count_1s<Max15>(undefended))
704 + InitKingDanger[relative_square(Us, ksq)]
705 - mg_value(ei.pi->king_shelter<Us>(pos, ksq)) / 32;
707 // Analyse enemy's safe queen contact checks. First find undefended
708 // squares around the king attacked by enemy queen...
709 b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
712 // ...then remove squares not supported by another enemy piece
713 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
714 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
716 attackUnits += QueenContactCheckBonus
718 * (Them == pos.side_to_move() ? 2 : 1);
721 // Analyse enemy's safe rook contact checks. First find undefended
722 // squares around the king attacked by enemy rooks...
723 b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
725 // Consider only squares where the enemy rook gives check
726 b &= RookPseudoAttacks[ksq];
730 // ...then remove squares not supported by another enemy piece
731 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
732 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]);
734 attackUnits += RookContactCheckBonus
736 * (Them == pos.side_to_move() ? 2 : 1);
739 // Analyse enemy's safe distance checks for sliders and knights
740 safe = ~(pos.pieces(Them) | ei.attackedBy[Us][0]);
742 b1 = pos.attacks_from<ROOK>(ksq) & safe;
743 b2 = pos.attacks_from<BISHOP>(ksq) & safe;
745 // Enemy queen safe checks
746 b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
748 attackUnits += QueenCheckBonus * count_1s<Max15>(b);
750 // Enemy rooks safe checks
751 b = b1 & ei.attackedBy[Them][ROOK];
753 attackUnits += RookCheckBonus * count_1s<Max15>(b);
755 // Enemy bishops safe checks
756 b = b2 & ei.attackedBy[Them][BISHOP];
758 attackUnits += BishopCheckBonus * count_1s<Max15>(b);
760 // Enemy knights safe checks
761 b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
763 attackUnits += KnightCheckBonus * count_1s<Max15>(b);
765 // To index KingDangerTable[] attackUnits must be in [0, 99] range
766 attackUnits = std::min(99, std::max(0, attackUnits));
768 // Finally, extract the king danger score from the KingDangerTable[]
769 // array and subtract the score from evaluation. Set also margins[]
770 // value that will be used for pruning because this value can sometimes
771 // be very big, and so capturing a single attacking piece can therefore
772 // result in a score change far bigger than the value of the captured piece.
773 score -= KingDangerTable[Us][attackUnits];
774 margins[Us] += mg_value(KingDangerTable[Us][attackUnits]);
778 TracedScores[Us][KING] = score;
784 // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
787 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
789 const Color Them = (Us == WHITE ? BLACK : WHITE);
791 Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
792 Score score = SCORE_ZERO;
794 b = ei.pi->passed_pawns(Us);
800 Square s = pop_1st_bit(&b);
802 assert(pos.pawn_is_passed(Us, s));
804 int r = int(relative_rank(Us, s) - RANK_2);
805 int rr = r * (r - 1);
807 // Base bonus based on rank
808 Value mbonus = Value(20 * rr);
809 Value ebonus = Value(10 * (rr + r + 1));
813 Square blockSq = s + pawn_push(Us);
815 // Adjust bonus based on kings proximity
816 ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 6 * rr);
817 ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 3 * rr);
819 // If blockSq is not the queening square then consider also a second push
820 if (rank_of(blockSq) != (Us == WHITE ? RANK_8 : RANK_1))
821 ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
823 // If the pawn is free to advance, increase bonus
824 if (pos.square_is_empty(blockSq))
826 squaresToQueen = squares_in_front_of(Us, s);
827 defendedSquares = squaresToQueen & ei.attackedBy[Us][0];
829 // If there is an enemy rook or queen attacking the pawn from behind,
830 // add all X-ray attacks by the rook or queen. Otherwise consider only
831 // the squares in the pawn's path attacked or occupied by the enemy.
832 if ( (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them))
833 && (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from<ROOK>(s)))
834 unsafeSquares = squaresToQueen;
836 unsafeSquares = squaresToQueen & (ei.attackedBy[Them][0] | pos.pieces(Them));
838 // If there aren't enemy attacks or pieces along the path to queen give
839 // huge bonus. Even bigger if we protect the pawn's path.
841 ebonus += Value(rr * (squaresToQueen == defendedSquares ? 17 : 15));
843 // OK, there are enemy attacks or pieces (but not pawns). Are those
844 // squares which are attacked by the enemy also attacked by us ?
845 // If yes, big bonus (but smaller than when there are no enemy attacks),
846 // if no, somewhat smaller bonus.
847 ebonus += Value(rr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8));
849 // At last, add a small bonus when there are no *friendly* pieces
850 // in the pawn's path.
851 if (!(squaresToQueen & pos.pieces(Us)))
856 // Increase the bonus if the passed pawn is supported by a friendly pawn
857 // on the same rank and a bit smaller if it's on the previous rank.
858 supportingPawns = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
859 if (supportingPawns & rank_bb(s))
860 ebonus += Value(r * 20);
861 else if (supportingPawns & rank_bb(s - pawn_push(Us)))
862 ebonus += Value(r * 12);
864 // Rook pawns are a special case: They are sometimes worse, and
865 // sometimes better than other passed pawns. It is difficult to find
866 // good rules for determining whether they are good or bad. For now,
867 // we try the following: Increase the value for rook pawns if the
868 // other side has no pieces apart from a knight, and decrease the
869 // value if the other side has a rook or queen.
870 if (file_of(s) == FILE_A || file_of(s) == FILE_H)
872 if (pos.non_pawn_material(Them) <= KnightValueMidgame)
873 ebonus += ebonus / 4;
874 else if (pos.pieces(ROOK, QUEEN, Them))
875 ebonus -= ebonus / 4;
877 score += make_score(mbonus, ebonus);
881 // Add the scores to the middle game and endgame eval
882 return apply_weight(score, Weights[PassedPawns]);
886 // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides, this is quite
887 // conservative and returns a winning score only when we are very sure that the pawn is winning.
889 template<bool HasPopCnt>
890 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
892 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
894 Bitboard b, b2, blockers, supporters, queeningPath, candidates;
895 Square s, blockSq, queeningSquare;
896 Color c, winnerSide, loserSide;
897 bool pathDefended, opposed;
898 int pliesToGo, movesToGo, oppMovesToGo, sacptg, blockersCount, minKingDist, kingptg, d;
899 int pliesToQueen[] = { 256, 256 };
901 // Step 1. Hunt for unstoppable passed pawns. If we find at least one,
902 // record how many plies are required for promotion.
903 for (c = WHITE; c <= BLACK; c++)
905 // Skip if other side has non-pawn pieces
906 if (pos.non_pawn_material(flip(c)))
909 b = ei.pi->passed_pawns(c);
914 queeningSquare = relative_square(c, make_square(file_of(s), RANK_8));
915 queeningPath = squares_in_front_of(c, s);
917 // Compute plies to queening and check direct advancement
918 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(c, s) == RANK_2);
919 oppMovesToGo = square_distance(pos.king_square(flip(c)), queeningSquare) - int(c != pos.side_to_move());
920 pathDefended = ((ei.attackedBy[c][0] & queeningPath) == queeningPath);
922 if (movesToGo >= oppMovesToGo && !pathDefended)
925 // Opponent king cannot block because path is defended and position
926 // is not in check. So only friendly pieces can be blockers.
927 assert(!pos.in_check());
928 assert((queeningPath & pos.occupied_squares()) == (queeningPath & pos.pieces(c)));
930 // Add moves needed to free the path from friendly pieces and retest condition
931 movesToGo += count_1s<Max15>(queeningPath & pos.pieces(c));
933 if (movesToGo >= oppMovesToGo && !pathDefended)
936 pliesToGo = 2 * movesToGo - int(c == pos.side_to_move());
937 pliesToQueen[c] = std::min(pliesToQueen[c], pliesToGo);
941 // Step 2. If either side cannot promote at least three plies before the other side then situation
942 // becomes too complex and we give up. Otherwise we determine the possibly "winning side"
943 if (abs(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3)
946 winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK);
947 loserSide = flip(winnerSide);
949 // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
950 b = candidates = pos.pieces(PAWN, loserSide);
956 // Compute plies from queening
957 queeningSquare = relative_square(loserSide, make_square(file_of(s), RANK_8));
958 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
959 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
961 // Check if (without even considering any obstacles) we're too far away or doubled
962 if ( pliesToQueen[winnerSide] + 3 <= pliesToGo
963 || (squares_in_front_of(loserSide, s) & pos.pieces(PAWN, loserSide)))
964 clear_bit(&candidates, s);
967 // If any candidate is already a passed pawn it _may_ promote in time. We give up.
968 if (candidates & ei.pi->passed_pawns(loserSide))
971 // Step 4. Check new passed pawn creation through king capturing and pawn sacrifices
977 sacptg = blockersCount = 0;
978 minKingDist = kingptg = 256;
980 // Compute plies from queening
981 queeningSquare = relative_square(loserSide, make_square(file_of(s), RANK_8));
982 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
983 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
985 // Generate list of blocking pawns and supporters
986 supporters = neighboring_files_bb(s) & candidates;
987 opposed = squares_in_front_of(loserSide, s) & pos.pieces(PAWN, winnerSide);
988 blockers = passed_pawn_mask(loserSide, s) & pos.pieces(PAWN, winnerSide);
992 // How many plies does it take to remove all the blocking pawns?
995 blockSq = pop_1st_bit(&blockers);
998 // Check pawns that can give support to overcome obstacle, for instance
999 // black pawns: a4, b4 white: b2 then pawn in b4 is giving support.
1002 b2 = supporters & in_front_bb(winnerSide, blockSq + pawn_push(winnerSide));
1004 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1006 d = square_distance(blockSq, pop_1st_bit(&b2)) - 2;
1007 movesToGo = std::min(movesToGo, d);
1011 // Check pawns that can be sacrificed against the blocking pawn
1012 b2 = attack_span_mask(winnerSide, blockSq) & candidates & ~(1ULL << s);
1014 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1016 d = square_distance(blockSq, pop_1st_bit(&b2)) - 2;
1017 movesToGo = std::min(movesToGo, d);
1020 // If obstacle can be destroyed with an immediate pawn exchange / sacrifice,
1021 // it's not a real obstacle and we have nothing to add to pliesToGo.
1025 // Plies needed to sacrifice against all the blocking pawns
1026 sacptg += movesToGo * 2;
1029 // Plies needed for the king to capture all the blocking pawns
1030 d = square_distance(pos.king_square(loserSide), blockSq);
1031 minKingDist = std::min(minKingDist, d);
1032 kingptg = (minKingDist + blockersCount) * 2;
1035 // Check if pawn sacrifice plan _may_ save the day
1036 if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg)
1039 // Check if king capture plan _may_ save the day (contains some false positives)
1040 if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg)
1044 // Winning pawn is unstoppable and will promote as first, return big score
1045 Score score = make_score(0, (Value) 0x500 - 0x20 * pliesToQueen[winnerSide]);
1046 return winnerSide == WHITE ? score : -score;
1050 // evaluate_space() computes the space evaluation for a given side. The
1051 // space evaluation is a simple bonus based on the number of safe squares
1052 // available for minor pieces on the central four files on ranks 2--4. Safe
1053 // squares one, two or three squares behind a friendly pawn are counted
1054 // twice. Finally, the space bonus is scaled by a weight taken from the
1055 // material hash table. The aim is to improve play on game opening.
1056 template<Color Us, bool HasPopCnt>
1057 int evaluate_space(const Position& pos, EvalInfo& ei) {
1059 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
1060 const Color Them = (Us == WHITE ? BLACK : WHITE);
1062 // Find the safe squares for our pieces inside the area defined by
1063 // SpaceMask[]. A square is unsafe if it is attacked by an enemy
1064 // pawn, or if it is undefended and attacked by an enemy piece.
1065 Bitboard safe = SpaceMask[Us]
1066 & ~pos.pieces(PAWN, Us)
1067 & ~ei.attackedBy[Them][PAWN]
1068 & (ei.attackedBy[Us][0] | ~ei.attackedBy[Them][0]);
1070 // Find all squares which are at most three squares behind some friendly pawn
1071 Bitboard behind = pos.pieces(PAWN, Us);
1072 behind |= (Us == WHITE ? behind >> 8 : behind << 8);
1073 behind |= (Us == WHITE ? behind >> 16 : behind << 16);
1075 return count_1s<Max15>(safe) + count_1s<Max15>(behind & safe);
1079 // apply_weight() applies an evaluation weight to a value trying to prevent overflow
1081 inline Score apply_weight(Score v, Score w) {
1082 return make_score((int(mg_value(v)) * mg_value(w)) / 0x100,
1083 (int(eg_value(v)) * eg_value(w)) / 0x100);
1087 // scale_by_game_phase() interpolates between a middle game and an endgame score,
1088 // based on game phase. It also scales the return value by a ScaleFactor array.
1090 Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf) {
1092 assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
1093 assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
1094 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1096 int ev = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
1097 int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128;
1098 return Value((result + GrainSize / 2) & ~(GrainSize - 1));
1102 // weight_option() computes the value of an evaluation weight, by combining
1103 // two UCI-configurable weights (midgame and endgame) with an internal weight.
1105 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
1107 // Scale option value from 100 to 256
1108 int mg = Options[mgOpt].value<int>() * 256 / 100;
1109 int eg = Options[egOpt].value<int>() * 256 / 100;
1111 return apply_weight(make_score(mg, eg), internalWeight);
1115 // init_safety() initizes the king safety evaluation, based on UCI
1116 // parameters. It is called from read_weights().
1118 void init_safety() {
1120 const Value MaxSlope = Value(30);
1121 const Value Peak = Value(1280);
1124 // First setup the base table
1125 for (int i = 0; i < 100; i++)
1127 t[i] = Value(int(0.4 * i * i));
1130 t[i] = std::min(t[i], t[i - 1] + MaxSlope);
1132 t[i] = std::min(t[i], Peak);
1135 // Then apply the weights and get the final KingDangerTable[] array
1136 for (Color c = WHITE; c <= BLACK; c++)
1137 for (int i = 0; i < 100; i++)
1138 KingDangerTable[c][i] = apply_weight(make_score(t[i], 0), Weights[KingDangerUs + c]);
1142 // A couple of little helpers used by tracing code, to_cp() converts a value to
1143 // a double in centipawns scale, trace_add() stores white and black scores.
1145 double to_cp(Value v) { return double(v) / double(PawnValueMidgame); }
1147 void trace_add(int idx, Score wScore, Score bScore) {
1149 TracedScores[WHITE][idx] = wScore;
1150 TracedScores[BLACK][idx] = bScore;
1153 // trace_row() is an helper function used by tracing code to register the
1154 // values of a single evaluation term.
1156 void trace_row(const char *name, int idx) {
1158 Score wScore = TracedScores[WHITE][idx];
1159 Score bScore = TracedScores[BLACK][idx];
1162 case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL:
1163 TraceStream << std::setw(20) << name << " | --- --- | --- --- | "
1164 << std::setw(6) << to_cp(mg_value(wScore)) << " "
1165 << std::setw(6) << to_cp(eg_value(wScore)) << " \n";
1168 TraceStream << std::setw(20) << name << " | " << std::noshowpos
1169 << std::setw(5) << to_cp(mg_value(wScore)) << " "
1170 << std::setw(5) << to_cp(eg_value(wScore)) << " | "
1171 << std::setw(5) << to_cp(mg_value(bScore)) << " "
1172 << std::setw(5) << to_cp(eg_value(bScore)) << " | "
1174 << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " "
1175 << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n";
1181 /// trace_evaluate() is like evaluate() but instead of a value returns a string
1182 /// suitable to be print on stdout with the detailed descriptions and values of
1183 /// each evaluation term. Used mainly for debugging.
1185 std::string trace_evaluate(const Position& pos) {
1190 TraceStream.str("");
1191 TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
1192 memset(TracedScores, 0, 2 * 16 * sizeof(Score));
1194 do_evaluate<false, true>(pos, margin);
1196 totals = TraceStream.str();
1197 TraceStream.str("");
1199 TraceStream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
1200 << " | MG EG | MG EG | MG EG \n"
1201 << "---------------------+-------------+-------------+---------------\n";
1203 trace_row("Material, PST, Tempo", PST);
1204 trace_row("Material imbalance", IMBALANCE);
1205 trace_row("Pawns", PAWN);
1206 trace_row("Knights", KNIGHT);
1207 trace_row("Bishops", BISHOP);
1208 trace_row("Rooks", ROOK);
1209 trace_row("Queens", QUEEN);
1210 trace_row("Mobility", MOBILITY);
1211 trace_row("King safety", KING);
1212 trace_row("Threats", THREAT);
1213 trace_row("Passed pawns", PASSED);
1214 trace_row("Unstoppable pawns", UNSTOPPABLE);
1215 trace_row("Space", SPACE);
1217 TraceStream << "---------------------+-------------+-------------+---------------\n";
1218 trace_row("Total", TOTAL);
1219 TraceStream << totals;
1221 return TraceStream.str();