2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2012 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(216, 266), 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
229 Value do_evaluate(const Position& pos, Value& margin);
232 void init_eval_info(const Position& pos, EvalInfo& ei);
234 template<Color Us, bool Trace>
235 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility);
237 template<Color Us, bool Trace>
238 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]);
241 Score evaluate_threats(const Position& pos, EvalInfo& ei);
244 int evaluate_space(const Position& pos, EvalInfo& ei);
247 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
249 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
251 inline Score apply_weight(Score v, Score weight);
252 Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf);
253 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
255 double to_cp(Value v);
256 void trace_add(int idx, Score term_w, Score term_b = SCORE_ZERO);
260 /// evaluate() is the main evaluation function. It always computes two
261 /// values, an endgame score and a middle game score, and interpolates
262 /// between them based on the remaining material.
263 Value evaluate(const Position& pos, Value& margin) { return do_evaluate<false>(pos, margin); }
268 Value do_evaluate(const Position& pos, Value& margin) {
272 Score score, mobilityWhite, mobilityBlack;
274 assert(pos.thread() >= 0 && pos.thread() < MAX_THREADS);
275 assert(!pos.in_check());
277 // Initialize score by reading the incrementally updated scores included
278 // in the position object (material + piece square tables).
281 // margins[] store the uncertainty estimation of position's evaluation
282 // that typically is used by the search for pruning decisions.
283 margins[WHITE] = margins[BLACK] = VALUE_ZERO;
285 // Probe the material hash table
286 ei.mi = Threads[pos.thread()].materialTable.material_info(pos);
287 score += ei.mi->material_value();
289 // If we have a specialized evaluation function for the current material
290 // configuration, call it and return.
291 if (ei.mi->specialized_eval_exists())
294 return ei.mi->evaluate(pos);
297 // Probe the pawn hash table
298 ei.pi = Threads[pos.thread()].pawnTable.pawn_info(pos);
299 score += ei.pi->pawns_value();
301 // Initialize attack and king safety bitboards
302 init_eval_info<WHITE>(pos, ei);
303 init_eval_info<BLACK>(pos, ei);
305 // Evaluate pieces and mobility
306 score += evaluate_pieces_of_color<WHITE, Trace>(pos, ei, mobilityWhite)
307 - evaluate_pieces_of_color<BLACK, Trace>(pos, ei, mobilityBlack);
309 score += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
311 // Evaluate kings after all other pieces because we need complete attack
312 // information when computing the king safety evaluation.
313 score += evaluate_king<WHITE, Trace>(pos, ei, margins)
314 - evaluate_king<BLACK, Trace>(pos, ei, margins);
316 // Evaluate tactical threats, we need full attack information including king
317 score += evaluate_threats<WHITE>(pos, ei)
318 - evaluate_threats<BLACK>(pos, ei);
320 // Evaluate passed pawns, we need full attack information including king
321 score += evaluate_passed_pawns<WHITE>(pos, ei)
322 - evaluate_passed_pawns<BLACK>(pos, ei);
324 // If one side has only a king, check whether exists any unstoppable passed pawn
325 if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
326 score += evaluate_unstoppable_pawns(pos, ei);
328 // Evaluate space for both sides, only in middle-game.
329 if (ei.mi->space_weight())
331 int s = evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei);
332 score += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]);
335 // Scale winning side if position is more drawish that what it appears
336 ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE)
337 : ei.mi->scale_factor(pos, BLACK);
339 // If we don't already have an unusual scale factor, check for opposite
340 // colored bishop endgames, and use a lower scale for those.
341 if ( ei.mi->game_phase() < PHASE_MIDGAME
342 && pos.opposite_colored_bishops()
343 && sf == SCALE_FACTOR_NORMAL)
345 // Only the two bishops ?
346 if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
347 && pos.non_pawn_material(BLACK) == BishopValueMidgame)
349 // Check for KBP vs KB with only a single pawn that is almost
350 // certainly a draw or at least two pawns.
351 bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
352 sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
355 // Endgame with opposite-colored bishops, but also other pieces. Still
356 // a bit drawish, but not as drawish as with only the two bishops.
357 sf = ScaleFactor(50);
360 // Interpolate between the middle game and the endgame score
361 margin = margins[pos.side_to_move()];
362 Value v = scale_by_game_phase(score, ei.mi->game_phase(), sf);
364 // In case of tracing add all single evaluation contributions for both white and black
367 trace_add(PST, pos.value());
368 trace_add(IMBALANCE, ei.mi->material_value());
369 trace_add(PAWN, ei.pi->pawns_value());
370 trace_add(MOBILITY, apply_weight(mobilityWhite, Weights[Mobility]), apply_weight(mobilityBlack, Weights[Mobility]));
371 trace_add(THREAT, evaluate_threats<WHITE>(pos, ei), evaluate_threats<BLACK>(pos, ei));
372 trace_add(PASSED, evaluate_passed_pawns<WHITE>(pos, ei), evaluate_passed_pawns<BLACK>(pos, ei));
373 trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns(pos, ei));
374 Score w = make_score(ei.mi->space_weight() * evaluate_space<WHITE>(pos, ei), 0);
375 Score b = make_score(ei.mi->space_weight() * evaluate_space<BLACK>(pos, ei), 0);
376 trace_add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
377 trace_add(TOTAL, score);
378 TraceStream << "\nUncertainty margin: White: " << to_cp(margins[WHITE])
379 << ", Black: " << to_cp(margins[BLACK])
380 << "\nScaling: " << std::noshowpos
381 << std::setw(6) << 100.0 * ei.mi->game_phase() / 128.0 << "% MG, "
382 << std::setw(6) << 100.0 * (1.0 - ei.mi->game_phase() / 128.0) << "% * "
383 << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
384 << "Total evaluation: " << to_cp(v);
387 return pos.side_to_move() == WHITE ? v : -v;
393 /// read_weights() reads evaluation weights from the corresponding UCI parameters
395 void read_evaluation_uci_options(Color us) {
397 // King safety is asymmetrical. Our king danger level is weighted by
398 // "Cowardice" UCI parameter, instead the opponent one by "Aggressiveness".
399 const int kingDangerUs = (us == WHITE ? KingDangerUs : KingDangerThem);
400 const int kingDangerThem = (us == WHITE ? KingDangerThem : KingDangerUs);
402 Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
403 Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
404 Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
405 Weights[kingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
406 Weights[kingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
408 // If running in analysis mode, make sure we use symmetrical king safety. We do this
409 // by replacing both Weights[kingDangerUs] and Weights[kingDangerThem] by their average.
410 if (Options["UCI_AnalyseMode"])
411 Weights[kingDangerUs] = Weights[kingDangerThem] = (Weights[kingDangerUs] + Weights[kingDangerThem]) / 2;
419 // init_eval_info() initializes king bitboards for given color adding
420 // pawn attacks. To be done at the beginning of the evaluation.
423 void init_eval_info(const Position& pos, EvalInfo& ei) {
425 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : Is64Bit ? CNT64_MAX15 : CNT32_MAX15;
426 const Color Them = (Us == WHITE ? BLACK : WHITE);
428 Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
429 ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
431 // Init king safety tables only if we are going to use them
432 if ( pos.piece_count(Us, QUEEN)
433 && pos.non_pawn_material(Us) >= QueenValueMidgame + RookValueMidgame)
435 ei.kingRing[Them] = (b | (Us == WHITE ? b >> 8 : b << 8));
436 b &= ei.attackedBy[Us][PAWN];
437 ei.kingAttackersCount[Us] = b ? count_1s<Max15>(b) / 2 : 0;
438 ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
440 ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0;
444 // evaluate_outposts() evaluates bishop and knight outposts squares
446 template<PieceType Piece, Color Us>
447 Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
449 const Color Them = (Us == WHITE ? BLACK : WHITE);
451 assert (Piece == BISHOP || Piece == KNIGHT);
453 // Initial bonus based on square
454 Value bonus = OutpostBonus[Piece == BISHOP][relative_square(Us, s)];
456 // Increase bonus if supported by pawn, especially if the opponent has
457 // no minor piece which can exchange the outpost piece.
458 if (bonus && bit_is_set(ei.attackedBy[Us][PAWN], s))
460 if ( !pos.pieces(KNIGHT, Them)
461 && !(same_color_squares(s) & pos.pieces(BISHOP, Them)))
462 bonus += bonus + bonus / 2;
466 return make_score(bonus, bonus);
470 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
472 template<PieceType Piece, Color Us, bool Trace>
473 Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
479 Score score = SCORE_ZERO;
481 const BitCountType Full = HasPopCnt ? CNT_POPCNT : Is64Bit ? CNT64 : CNT32;
482 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : Is64Bit ? CNT64_MAX15 : CNT32_MAX15;
483 const Color Them = (Us == WHITE ? BLACK : WHITE);
484 const Square* pl = pos.piece_list(Us, Piece);
486 ei.attackedBy[Us][Piece] = 0;
488 while ((s = *pl++) != SQ_NONE)
490 // Find attacked squares, including x-ray attacks for bishops and rooks
491 if (Piece == KNIGHT || Piece == QUEEN)
492 b = pos.attacks_from<Piece>(s);
493 else if (Piece == BISHOP)
494 b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
495 else if (Piece == ROOK)
496 b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
500 // Update attack info
501 ei.attackedBy[Us][Piece] |= b;
504 if (b & ei.kingRing[Them])
506 ei.kingAttackersCount[Us]++;
507 ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
508 Bitboard bb = (b & ei.attackedBy[Them][KING]);
510 ei.kingAdjacentZoneAttacksCount[Us] += count_1s<Max15>(bb);
514 mob = (Piece != QUEEN ? count_1s<Max15>(b & mobilityArea)
515 : count_1s<Full >(b & mobilityArea));
517 mobility += MobilityBonus[Piece][mob];
519 // Decrease score if we are attacked by an enemy pawn. Remaining part
520 // of threat evaluation must be done later when we have full attack info.
521 if (bit_is_set(ei.attackedBy[Them][PAWN], s))
522 score -= ThreatenedByPawnPenalty[Piece];
524 // Bishop and knight outposts squares
525 if ( (Piece == BISHOP || Piece == KNIGHT)
526 && !(pos.pieces(PAWN, Them) & attack_span_mask(Us, s)))
527 score += evaluate_outposts<Piece, Us>(pos, ei, s);
529 // Queen or rook on 7th rank
530 if ( (Piece == ROOK || Piece == QUEEN)
531 && relative_rank(Us, s) == RANK_7
532 && relative_rank(Us, pos.king_square(Them)) == RANK_8)
534 score += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
537 // Special extra evaluation for bishops
538 if (Piece == BISHOP && pos.is_chess960())
540 // An important Chess960 pattern: A cornered bishop blocked by
541 // a friendly pawn diagonally in front of it is a very serious
542 // problem, especially when that pawn is also blocked.
543 if (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1))
545 Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
546 if (pos.piece_on(s + d) == make_piece(Us, PAWN))
548 if (!pos.square_is_empty(s + d + pawn_push(Us)))
549 score -= 2*TrappedBishopA1H1Penalty;
550 else if (pos.piece_on(s + 2*d) == make_piece(Us, PAWN))
551 score -= TrappedBishopA1H1Penalty;
553 score -= TrappedBishopA1H1Penalty / 2;
558 // Special extra evaluation for rooks
561 // Open and half-open files
563 if (ei.pi->file_is_half_open(Us, f))
565 if (ei.pi->file_is_half_open(Them, f))
566 score += RookOpenFileBonus;
568 score += RookHalfOpenFileBonus;
571 // Penalize rooks which are trapped inside a king. Penalize more if
572 // king has lost right to castle.
573 if (mob > 6 || ei.pi->file_is_half_open(Us, f))
576 ksq = pos.king_square(Us);
578 if ( file_of(ksq) >= FILE_E
579 && file_of(s) > file_of(ksq)
580 && (relative_rank(Us, ksq) == RANK_1 || rank_of(ksq) == rank_of(s)))
582 // Is there a half-open file between the king and the edge of the board?
583 if (!ei.pi->has_open_file_to_right(Us, file_of(ksq)))
584 score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
585 : (TrappedRookPenalty - mob * 16), 0);
587 else if ( file_of(ksq) <= FILE_D
588 && file_of(s) < file_of(ksq)
589 && (relative_rank(Us, ksq) == RANK_1 || rank_of(ksq) == rank_of(s)))
591 // Is there a half-open file between the king and the edge of the board?
592 if (!ei.pi->has_open_file_to_left(Us, file_of(ksq)))
593 score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
594 : (TrappedRookPenalty - mob * 16), 0);
600 TracedScores[Us][Piece] = score;
606 // evaluate_threats<>() assigns bonuses according to the type of attacking piece
607 // and the type of attacked one.
610 Score evaluate_threats(const Position& pos, EvalInfo& ei) {
612 const Color Them = (Us == WHITE ? BLACK : WHITE);
615 Score score = SCORE_ZERO;
617 // Enemy pieces not defended by a pawn and under our attack
618 Bitboard weakEnemies = pos.pieces(Them)
619 & ~ei.attackedBy[Them][PAWN]
620 & ei.attackedBy[Us][0];
624 // Add bonus according to type of attacked enemy piece and to the
625 // type of attacking piece, from knights to queens. Kings are not
626 // considered because are already handled in king evaluation.
627 for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
629 b = ei.attackedBy[Us][pt1] & weakEnemies;
631 for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
632 if (b & pos.pieces(pt2))
633 score += ThreatBonus[pt1][pt2];
639 // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
640 // pieces of a given color.
642 template<Color Us, bool Trace>
643 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) {
645 const Color Them = (Us == WHITE ? BLACK : WHITE);
647 Score score = mobility = SCORE_ZERO;
649 // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
650 const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces(Us));
652 score += evaluate_pieces<KNIGHT, Us, Trace>(pos, ei, mobility, mobilityArea);
653 score += evaluate_pieces<BISHOP, Us, Trace>(pos, ei, mobility, mobilityArea);
654 score += evaluate_pieces<ROOK, Us, Trace>(pos, ei, mobility, mobilityArea);
655 score += evaluate_pieces<QUEEN, Us, Trace>(pos, ei, mobility, mobilityArea);
657 // Sum up all attacked squares
658 ei.attackedBy[Us][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
659 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
660 | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
665 // evaluate_king<>() assigns bonuses and penalties to a king of a given color
667 template<Color Us, bool Trace>
668 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
670 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : Is64Bit ? CNT64_MAX15 : CNT32_MAX15;
671 const Color Them = (Us == WHITE ? BLACK : WHITE);
673 Bitboard undefended, b, b1, b2, safe;
675 const Square ksq = pos.king_square(Us);
678 Score score = ei.pi->king_shelter<Us>(pos, ksq);
680 // King safety. This is quite complicated, and is almost certainly far
681 // from optimally tuned.
682 if ( ei.kingAttackersCount[Them] >= 2
683 && ei.kingAdjacentZoneAttacksCount[Them])
685 // Find the attacked squares around the king which has no defenders
686 // apart from the king itself
687 undefended = ei.attackedBy[Them][0] & ei.attackedBy[Us][KING];
688 undefended &= ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
689 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
690 | ei.attackedBy[Us][QUEEN]);
692 // Initialize the 'attackUnits' variable, which is used later on as an
693 // index to the KingDangerTable[] array. The initial value is based on
694 // the number and types of the enemy's attacking pieces, the number of
695 // attacked and undefended squares around our king, the square of the
696 // king, and the quality of the pawn shelter.
697 attackUnits = std::min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
698 + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + count_1s<Max15>(undefended))
699 + InitKingDanger[relative_square(Us, ksq)]
700 - mg_value(ei.pi->king_shelter<Us>(pos, ksq)) / 32;
702 // Analyse enemy's safe queen contact checks. First find undefended
703 // squares around the king attacked by enemy queen...
704 b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
707 // ...then remove squares not supported by another enemy piece
708 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
709 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
711 attackUnits += QueenContactCheckBonus
713 * (Them == pos.side_to_move() ? 2 : 1);
716 // Analyse enemy's safe rook contact checks. First find undefended
717 // squares around the king attacked by enemy rooks...
718 b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
720 // Consider only squares where the enemy rook gives check
721 b &= RookPseudoAttacks[ksq];
725 // ...then remove squares not supported by another enemy piece
726 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
727 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]);
729 attackUnits += RookContactCheckBonus
731 * (Them == pos.side_to_move() ? 2 : 1);
734 // Analyse enemy's safe distance checks for sliders and knights
735 safe = ~(pos.pieces(Them) | ei.attackedBy[Us][0]);
737 b1 = pos.attacks_from<ROOK>(ksq) & safe;
738 b2 = pos.attacks_from<BISHOP>(ksq) & safe;
740 // Enemy queen safe checks
741 b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
743 attackUnits += QueenCheckBonus * count_1s<Max15>(b);
745 // Enemy rooks safe checks
746 b = b1 & ei.attackedBy[Them][ROOK];
748 attackUnits += RookCheckBonus * count_1s<Max15>(b);
750 // Enemy bishops safe checks
751 b = b2 & ei.attackedBy[Them][BISHOP];
753 attackUnits += BishopCheckBonus * count_1s<Max15>(b);
755 // Enemy knights safe checks
756 b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
758 attackUnits += KnightCheckBonus * count_1s<Max15>(b);
760 // To index KingDangerTable[] attackUnits must be in [0, 99] range
761 attackUnits = std::min(99, std::max(0, attackUnits));
763 // Finally, extract the king danger score from the KingDangerTable[]
764 // array and subtract the score from evaluation. Set also margins[]
765 // value that will be used for pruning because this value can sometimes
766 // be very big, and so capturing a single attacking piece can therefore
767 // result in a score change far bigger than the value of the captured piece.
768 score -= KingDangerTable[Us][attackUnits];
769 margins[Us] += mg_value(KingDangerTable[Us][attackUnits]);
773 TracedScores[Us][KING] = score;
779 // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
782 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
784 const Color Them = (Us == WHITE ? BLACK : WHITE);
786 Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
787 Score score = SCORE_ZERO;
789 b = ei.pi->passed_pawns(Us);
795 Square s = pop_1st_bit(&b);
797 assert(pos.pawn_is_passed(Us, s));
799 int r = int(relative_rank(Us, s) - RANK_2);
800 int rr = r * (r - 1);
802 // Base bonus based on rank
803 Value mbonus = Value(20 * rr);
804 Value ebonus = Value(10 * (rr + r + 1));
808 Square blockSq = s + pawn_push(Us);
810 // Adjust bonus based on kings proximity
811 ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 5 * rr);
812 ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 2 * rr);
814 // If blockSq is not the queening square then consider also a second push
815 if (rank_of(blockSq) != (Us == WHITE ? RANK_8 : RANK_1))
816 ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
818 // If the pawn is free to advance, increase bonus
819 if (pos.square_is_empty(blockSq))
821 squaresToQueen = squares_in_front_of(Us, s);
822 defendedSquares = squaresToQueen & ei.attackedBy[Us][0];
824 // If there is an enemy rook or queen attacking the pawn from behind,
825 // add all X-ray attacks by the rook or queen. Otherwise consider only
826 // the squares in the pawn's path attacked or occupied by the enemy.
827 if ( (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them))
828 && (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from<ROOK>(s)))
829 unsafeSquares = squaresToQueen;
831 unsafeSquares = squaresToQueen & (ei.attackedBy[Them][0] | pos.pieces(Them));
833 // If there aren't enemy attacks or pieces along the path to queen give
834 // huge bonus. Even bigger if we protect the pawn's path.
836 ebonus += Value(rr * (squaresToQueen == defendedSquares ? 17 : 15));
838 // OK, there are enemy attacks or pieces (but not pawns). Are those
839 // squares which are attacked by the enemy also attacked by us ?
840 // If yes, big bonus (but smaller than when there are no enemy attacks),
841 // if no, somewhat smaller bonus.
842 ebonus += Value(rr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8));
846 // Increase the bonus if the passed pawn is supported by a friendly pawn
847 // on the same rank and a bit smaller if it's on the previous rank.
848 supportingPawns = pos.pieces(PAWN, Us) & neighboring_files_bb(file_of(s));
849 if (supportingPawns & rank_bb(s))
850 ebonus += Value(r * 20);
852 else if (supportingPawns & rank_bb(s - pawn_push(Us)))
853 ebonus += Value(r * 12);
855 // Rook pawns are a special case: They are sometimes worse, and
856 // sometimes better than other passed pawns. It is difficult to find
857 // good rules for determining whether they are good or bad. For now,
858 // we try the following: Increase the value for rook pawns if the
859 // other side has no pieces apart from a knight, and decrease the
860 // value if the other side has a rook or queen.
861 if (file_of(s) == FILE_A || file_of(s) == FILE_H)
863 if (pos.non_pawn_material(Them) <= KnightValueMidgame)
864 ebonus += ebonus / 4;
865 else if (pos.pieces(ROOK, QUEEN, Them))
866 ebonus -= ebonus / 4;
868 score += make_score(mbonus, ebonus);
872 // Add the scores to the middle game and endgame eval
873 return apply_weight(score, Weights[PassedPawns]);
877 // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides, this is quite
878 // conservative and returns a winning score only when we are very sure that the pawn is winning.
880 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
882 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : Is64Bit ? CNT64_MAX15 : CNT32_MAX15;
884 Bitboard b, b2, blockers, supporters, queeningPath, candidates;
885 Square s, blockSq, queeningSquare;
886 Color c, winnerSide, loserSide;
887 bool pathDefended, opposed;
888 int pliesToGo, movesToGo, oppMovesToGo, sacptg, blockersCount, minKingDist, kingptg, d;
889 int pliesToQueen[] = { 256, 256 };
891 // Step 1. Hunt for unstoppable passed pawns. If we find at least one,
892 // record how many plies are required for promotion.
893 for (c = WHITE; c <= BLACK; c++)
895 // Skip if other side has non-pawn pieces
896 if (pos.non_pawn_material(flip(c)))
899 b = ei.pi->passed_pawns(c);
904 queeningSquare = relative_square(c, make_square(file_of(s), RANK_8));
905 queeningPath = squares_in_front_of(c, s);
907 // Compute plies to queening and check direct advancement
908 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(c, s) == RANK_2);
909 oppMovesToGo = square_distance(pos.king_square(flip(c)), queeningSquare) - int(c != pos.side_to_move());
910 pathDefended = ((ei.attackedBy[c][0] & queeningPath) == queeningPath);
912 if (movesToGo >= oppMovesToGo && !pathDefended)
915 // Opponent king cannot block because path is defended and position
916 // is not in check. So only friendly pieces can be blockers.
917 assert(!pos.in_check());
918 assert((queeningPath & pos.occupied_squares()) == (queeningPath & pos.pieces(c)));
920 // Add moves needed to free the path from friendly pieces and retest condition
921 movesToGo += count_1s<Max15>(queeningPath & pos.pieces(c));
923 if (movesToGo >= oppMovesToGo && !pathDefended)
926 pliesToGo = 2 * movesToGo - int(c == pos.side_to_move());
927 pliesToQueen[c] = std::min(pliesToQueen[c], pliesToGo);
931 // Step 2. If either side cannot promote at least three plies before the other side then situation
932 // becomes too complex and we give up. Otherwise we determine the possibly "winning side"
933 if (abs(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3)
936 winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK);
937 loserSide = flip(winnerSide);
939 // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
940 b = candidates = pos.pieces(PAWN, loserSide);
946 // Compute plies from queening
947 queeningSquare = relative_square(loserSide, make_square(file_of(s), RANK_8));
948 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
949 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
951 // Check if (without even considering any obstacles) we're too far away or doubled
952 if ( pliesToQueen[winnerSide] + 3 <= pliesToGo
953 || (squares_in_front_of(loserSide, s) & pos.pieces(PAWN, loserSide)))
954 clear_bit(&candidates, s);
957 // If any candidate is already a passed pawn it _may_ promote in time. We give up.
958 if (candidates & ei.pi->passed_pawns(loserSide))
961 // Step 4. Check new passed pawn creation through king capturing and pawn sacrifices
967 sacptg = blockersCount = 0;
968 minKingDist = kingptg = 256;
970 // Compute plies from queening
971 queeningSquare = relative_square(loserSide, make_square(file_of(s), RANK_8));
972 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
973 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
975 // Generate list of blocking pawns and supporters
976 supporters = neighboring_files_bb(file_of(s)) & candidates;
977 opposed = squares_in_front_of(loserSide, s) & pos.pieces(PAWN, winnerSide);
978 blockers = passed_pawn_mask(loserSide, s) & pos.pieces(PAWN, winnerSide);
982 // How many plies does it take to remove all the blocking pawns?
985 blockSq = pop_1st_bit(&blockers);
988 // Check pawns that can give support to overcome obstacle, for instance
989 // black pawns: a4, b4 white: b2 then pawn in b4 is giving support.
992 b2 = supporters & in_front_bb(winnerSide, blockSq + pawn_push(winnerSide));
994 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
996 d = square_distance(blockSq, pop_1st_bit(&b2)) - 2;
997 movesToGo = std::min(movesToGo, d);
1001 // Check pawns that can be sacrificed against the blocking pawn
1002 b2 = attack_span_mask(winnerSide, blockSq) & candidates & ~(1ULL << s);
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);
1010 // If obstacle can be destroyed with an immediate pawn exchange / sacrifice,
1011 // it's not a real obstacle and we have nothing to add to pliesToGo.
1015 // Plies needed to sacrifice against all the blocking pawns
1016 sacptg += movesToGo * 2;
1019 // Plies needed for the king to capture all the blocking pawns
1020 d = square_distance(pos.king_square(loserSide), blockSq);
1021 minKingDist = std::min(minKingDist, d);
1022 kingptg = (minKingDist + blockersCount) * 2;
1025 // Check if pawn sacrifice plan _may_ save the day
1026 if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg)
1029 // Check if king capture plan _may_ save the day (contains some false positives)
1030 if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg)
1034 // Winning pawn is unstoppable and will promote as first, return big score
1035 Score score = make_score(0, (Value) 0x500 - 0x20 * pliesToQueen[winnerSide]);
1036 return winnerSide == WHITE ? score : -score;
1040 // evaluate_space() computes the space evaluation for a given side. The
1041 // space evaluation is a simple bonus based on the number of safe squares
1042 // available for minor pieces on the central four files on ranks 2--4. Safe
1043 // squares one, two or three squares behind a friendly pawn are counted
1044 // twice. Finally, the space bonus is scaled by a weight taken from the
1045 // material hash table. The aim is to improve play on game opening.
1047 int evaluate_space(const Position& pos, EvalInfo& ei) {
1049 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : Is64Bit ? CNT64_MAX15 : CNT32_MAX15;
1050 const Color Them = (Us == WHITE ? BLACK : WHITE);
1052 // Find the safe squares for our pieces inside the area defined by
1053 // SpaceMask[]. A square is unsafe if it is attacked by an enemy
1054 // pawn, or if it is undefended and attacked by an enemy piece.
1055 Bitboard safe = SpaceMask[Us]
1056 & ~pos.pieces(PAWN, Us)
1057 & ~ei.attackedBy[Them][PAWN]
1058 & (ei.attackedBy[Us][0] | ~ei.attackedBy[Them][0]);
1060 // Find all squares which are at most three squares behind some friendly pawn
1061 Bitboard behind = pos.pieces(PAWN, Us);
1062 behind |= (Us == WHITE ? behind >> 8 : behind << 8);
1063 behind |= (Us == WHITE ? behind >> 16 : behind << 16);
1065 return count_1s<Max15>(safe) + count_1s<Max15>(behind & safe);
1069 // apply_weight() applies an evaluation weight to a value trying to prevent overflow
1071 inline Score apply_weight(Score v, Score w) {
1072 return make_score((int(mg_value(v)) * mg_value(w)) / 0x100,
1073 (int(eg_value(v)) * eg_value(w)) / 0x100);
1077 // scale_by_game_phase() interpolates between a middle game and an endgame score,
1078 // based on game phase. It also scales the return value by a ScaleFactor array.
1080 Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf) {
1082 assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
1083 assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
1084 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1086 int ev = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
1087 int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128;
1088 return Value((result + GrainSize / 2) & ~(GrainSize - 1));
1092 // weight_option() computes the value of an evaluation weight, by combining
1093 // two UCI-configurable weights (midgame and endgame) with an internal weight.
1095 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
1097 // Scale option value from 100 to 256
1098 int mg = Options[mgOpt] * 256 / 100;
1099 int eg = Options[egOpt] * 256 / 100;
1101 return apply_weight(make_score(mg, eg), internalWeight);
1105 // init_safety() initizes the king safety evaluation, based on UCI
1106 // parameters. It is called from read_weights().
1108 void init_safety() {
1110 const Value MaxSlope = Value(30);
1111 const Value Peak = Value(1280);
1114 // First setup the base table
1115 for (int i = 0; i < 100; i++)
1117 t[i] = Value(int(0.4 * i * i));
1120 t[i] = std::min(t[i], t[i - 1] + MaxSlope);
1122 t[i] = std::min(t[i], Peak);
1125 // Then apply the weights and get the final KingDangerTable[] array
1126 for (Color c = WHITE; c <= BLACK; c++)
1127 for (int i = 0; i < 100; i++)
1128 KingDangerTable[c][i] = apply_weight(make_score(t[i], 0), Weights[KingDangerUs + c]);
1132 // A couple of little helpers used by tracing code, to_cp() converts a value to
1133 // a double in centipawns scale, trace_add() stores white and black scores.
1135 double to_cp(Value v) { return double(v) / double(PawnValueMidgame); }
1137 void trace_add(int idx, Score wScore, Score bScore) {
1139 TracedScores[WHITE][idx] = wScore;
1140 TracedScores[BLACK][idx] = bScore;
1143 // trace_row() is an helper function used by tracing code to register the
1144 // values of a single evaluation term.
1146 void trace_row(const char *name, int idx) {
1148 Score wScore = TracedScores[WHITE][idx];
1149 Score bScore = TracedScores[BLACK][idx];
1152 case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL:
1153 TraceStream << std::setw(20) << name << " | --- --- | --- --- | "
1154 << std::setw(6) << to_cp(mg_value(wScore)) << " "
1155 << std::setw(6) << to_cp(eg_value(wScore)) << " \n";
1158 TraceStream << std::setw(20) << name << " | " << std::noshowpos
1159 << std::setw(5) << to_cp(mg_value(wScore)) << " "
1160 << std::setw(5) << to_cp(eg_value(wScore)) << " | "
1161 << std::setw(5) << to_cp(mg_value(bScore)) << " "
1162 << std::setw(5) << to_cp(eg_value(bScore)) << " | "
1164 << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " "
1165 << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n";
1171 /// trace_evaluate() is like evaluate() but instead of a value returns a string
1172 /// suitable to be print on stdout with the detailed descriptions and values of
1173 /// each evaluation term. Used mainly for debugging.
1175 std::string trace_evaluate(const Position& pos) {
1180 TraceStream.str("");
1181 TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
1182 memset(TracedScores, 0, 2 * 16 * sizeof(Score));
1184 do_evaluate<true>(pos, margin);
1186 totals = TraceStream.str();
1187 TraceStream.str("");
1189 TraceStream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
1190 << " | MG EG | MG EG | MG EG \n"
1191 << "---------------------+-------------+-------------+---------------\n";
1193 trace_row("Material, PST, Tempo", PST);
1194 trace_row("Material imbalance", IMBALANCE);
1195 trace_row("Pawns", PAWN);
1196 trace_row("Knights", KNIGHT);
1197 trace_row("Bishops", BISHOP);
1198 trace_row("Rooks", ROOK);
1199 trace_row("Queens", QUEEN);
1200 trace_row("Mobility", MOBILITY);
1201 trace_row("King safety", KING);
1202 trace_row("Threats", THREAT);
1203 trace_row("Passed pawns", PASSED);
1204 trace_row("Unstoppable pawns", UNSTOPPABLE);
1205 trace_row("Space", SPACE);
1207 TraceStream << "---------------------+-------------+-------------+---------------\n";
1208 trace_row("Total", TOTAL);
1209 TraceStream << totals;
1211 return TraceStream.str();