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/>.
30 #include "ucioption.h"
34 // Struct EvalInfo contains various information computed and collected
35 // by the evaluation functions.
38 // Pointers to material and pawn hash table entries
42 // attackedBy[color][piece type] is a bitboard representing all squares
43 // attacked by a given color and piece type, attackedBy[color][0] contains
44 // all squares attacked by the given color.
45 Bitboard attackedBy[2][8];
47 // kingZone[color] is the zone around the enemy king which is considered
48 // by the king safety evaluation. This consists of the squares directly
49 // adjacent to the king, and the three (or two, for a king on an edge file)
50 // squares two ranks in front of the king. For instance, if black's king
51 // is on g8, kingZone[WHITE] is a bitboard containing the squares f8, h8,
52 // f7, g7, h7, f6, g6 and h6.
55 // kingAttackersCount[color] is the number of pieces of the given color
56 // which attack a square in the kingZone of the enemy king.
57 int kingAttackersCount[2];
59 // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
60 // given color which attack a square in the kingZone of the enemy king. The
61 // weights of the individual piece types are given by the variables
62 // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
63 // KnightAttackWeight in evaluate.cpp
64 int kingAttackersWeight[2];
66 // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
67 // directly adjacent to the king of the given color. Pieces which attack
68 // more than one square are counted multiple times. For instance, if black's
69 // king is on g8 and there's a white knight on g5, this knight adds
70 // 2 to kingAdjacentZoneAttacksCount[BLACK].
71 int kingAdjacentZoneAttacksCount[2];
74 // Evaluation grain size, must be a power of 2
75 const int GrainSize = 8;
77 // Evaluation weights, initialized from UCI options
78 enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem };
82 #define S(mg, eg) make_score(mg, eg)
84 // Internal evaluation weights. These are applied on top of the evaluation
85 // weights read from UCI parameters. The purpose is to be able to change
86 // the evaluation weights while keeping the default values of the UCI
87 // parameters at 100, which looks prettier.
89 // Values modified by Joona Kiiski
90 const Score WeightsInternal[] = {
91 S(248, 271), S(233, 201), S(252, 259), S(46, 0), S(247, 0), S(259, 0)
94 // MobilityBonus[PieceType][attacked] contains mobility bonuses for middle and
95 // end game, indexed by piece type and number of attacked squares not occupied
96 // by friendly pieces.
97 const Score MobilityBonus[][32] = {
99 { S(-38,-33), S(-25,-23), S(-12,-13), S( 0, -3), S(12, 7), S(25, 17), // Knights
100 S( 31, 22), S( 38, 27), S( 38, 27) },
101 { S(-25,-30), S(-11,-16), S( 3, -2), S(17, 12), S(31, 26), S(45, 40), // Bishops
102 S( 57, 52), S( 65, 60), S( 71, 65), S(74, 69), S(76, 71), S(78, 73),
103 S( 79, 74), S( 80, 75), S( 81, 76), S(81, 76) },
104 { S(-20,-36), S(-14,-19), S( -8, -3), S(-2, 13), S( 4, 29), S(10, 46), // Rooks
105 S( 14, 62), S( 19, 79), S( 23, 95), S(26,106), S(27,111), S(28,114),
106 S( 29,116), S( 30,117), S( 31,118), S(32,118) },
107 { S(-10,-18), S( -8,-13), S( -6, -7), S(-3, -2), S(-1, 3), S( 1, 8), // Queens
108 S( 3, 13), S( 5, 19), S( 8, 23), S(10, 27), S(12, 32), S(15, 34),
109 S( 16, 35), S( 17, 35), S( 18, 35), S(20, 35), S(20, 35), S(20, 35),
110 S( 20, 35), S( 20, 35), S( 20, 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) }
115 // OutpostBonus[PieceType][Square] contains outpost bonuses of knights and
116 // bishops, indexed by piece type and square (from white's point of view).
117 const Value OutpostBonus[][64] = {
120 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Knights
121 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
122 V(0), V(0), V(4), V(8), V(8), V(4), V(0), V(0),
123 V(0), V(4),V(17),V(26),V(26),V(17), V(4), V(0),
124 V(0), V(8),V(26),V(35),V(35),V(26), V(8), V(0),
125 V(0), V(4),V(17),V(17),V(17),V(17), V(4), V(0) },
127 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Bishops
128 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
129 V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0),
130 V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0),
131 V(0),V(10),V(21),V(21),V(21),V(21),V(10), V(0),
132 V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0) }
135 // ThreatBonus[attacking][attacked] contains threat bonuses according to
136 // which piece type attacks which one.
137 const Score ThreatBonus[][8] = {
139 { S(0, 0), S( 7, 39), S( 0, 0), S(24, 49), S(41,100), S(41,100) }, // KNIGHT
140 { S(0, 0), S( 7, 39), S(24, 49), S( 0, 0), S(41,100), S(41,100) }, // BISHOP
141 { S(0, 0), S(-1, 29), S(15, 49), S(15, 49), S( 0, 0), S(24, 49) }, // ROOK
142 { S(0, 0), S(15, 39), S(15, 39), S(15, 39), S(15, 39), S( 0, 0) } // QUEEN
145 // ThreatedByPawnPenalty[PieceType] contains a penalty according to which
146 // piece type is attacked by an enemy pawn.
147 const Score ThreatedByPawnPenalty[] = {
148 S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
153 // Rooks and queens on the 7th rank (modified by Joona Kiiski)
154 const Score RookOn7thBonus = make_score(47, 98);
155 const Score QueenOn7thBonus = make_score(27, 54);
157 // Rooks on open files (modified by Joona Kiiski)
158 const Score RookOpenFileBonus = make_score(43, 43);
159 const Score RookHalfOpenFileBonus = make_score(19, 19);
161 // Penalty for rooks trapped inside a friendly king which has lost the
163 const Value TrappedRookPenalty = Value(180);
165 // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
166 // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
167 // happen in Chess960 games.
168 const Score TrappedBishopA1H1Penalty = make_score(100, 100);
170 // The SpaceMask[Color] contains the area of the board which is considered
171 // by the space evaluation. In the middle game, each side is given a bonus
172 // based on how many squares inside this area are safe and available for
173 // friendly minor pieces.
174 const Bitboard SpaceMask[] = {
175 (1ULL << SQ_C2) | (1ULL << SQ_D2) | (1ULL << SQ_E2) | (1ULL << SQ_F2) |
176 (1ULL << SQ_C3) | (1ULL << SQ_D3) | (1ULL << SQ_E3) | (1ULL << SQ_F3) |
177 (1ULL << SQ_C4) | (1ULL << SQ_D4) | (1ULL << SQ_E4) | (1ULL << SQ_F4),
178 (1ULL << SQ_C7) | (1ULL << SQ_D7) | (1ULL << SQ_E7) | (1ULL << SQ_F7) |
179 (1ULL << SQ_C6) | (1ULL << SQ_D6) | (1ULL << SQ_E6) | (1ULL << SQ_F6) |
180 (1ULL << SQ_C5) | (1ULL << SQ_D5) | (1ULL << SQ_E5) | (1ULL << SQ_F5)
183 // King danger constants and variables. The king danger scores are taken
184 // from the KingDangerTable[]. Various little "meta-bonuses" measuring
185 // the strength of the enemy attack are added up into an integer, which
186 // is used as an index to KingDangerTable[].
188 // KingAttackWeights[PieceType] contains king attack weights by piece type
189 const int KingAttackWeights[] = { 0, 0, 2, 2, 3, 5 };
191 // Bonuses for enemy's safe checks
192 const int QueenContactCheckBonus = 6;
193 const int RookContactCheckBonus = 4;
194 const int QueenCheckBonus = 3;
195 const int RookCheckBonus = 2;
196 const int BishopCheckBonus = 1;
197 const int KnightCheckBonus = 1;
199 // InitKingDanger[Square] contains penalties based on the position of the
200 // defending king, indexed by king's square (from white's point of view).
201 const int InitKingDanger[] = {
202 2, 0, 2, 5, 5, 2, 0, 2,
203 2, 2, 4, 8, 8, 4, 2, 2,
204 7, 10, 12, 12, 12, 12, 10, 7,
205 15, 15, 15, 15, 15, 15, 15, 15,
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
212 // KingDangerTable[Color][attackUnits] contains the actual king danger
213 // weighted scores, indexed by color and by a calculated integer number.
214 Score KingDangerTable[2][128];
216 // TracedTerms[Color][PieceType || TracedType] contains a breakdown of the
217 // evaluation terms, used when tracing.
218 Score TracedScores[2][16];
219 std::stringstream TraceStream;
222 PST = 8, IMBALANCE = 9, MOBILITY = 10, THREAT = 11,
223 PASSED = 12, UNSTOPPABLE = 13, SPACE = 14, TOTAL = 15
226 // Function prototypes
227 template<bool HasPopCnt, bool Trace>
228 Value do_evaluate(const Position& pos, Value& margin);
230 template<Color Us, bool HasPopCnt>
231 void init_eval_info(const Position& pos, EvalInfo& ei);
233 template<Color Us, bool HasPopCnt, bool Trace>
234 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility);
236 template<Color Us, bool HasPopCnt, bool Trace>
237 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]);
240 Score evaluate_threats(const Position& pos, EvalInfo& ei);
242 template<Color Us, bool HasPopCnt>
243 int evaluate_space(const Position& pos, EvalInfo& ei);
246 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
248 template<bool HasPopCnt>
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) {
265 return CpuHasPOPCNT ? do_evaluate<true, false>(pos, margin)
266 : do_evaluate<false, false>(pos, margin);
271 template<bool HasPopCnt, bool Trace>
272 Value do_evaluate(const Position& pos, Value& margin) {
276 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 += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
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, apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]));
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[PawnStructure] = weight_option("Pawn Structure (Middle Game)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
409 Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
410 Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
411 Weights[kingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
412 Weights[kingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
414 // If running in analysis mode, make sure we use symmetrical king safety. We do this
415 // by replacing both Weights[kingDangerUs] and Weights[kingDangerThem] by their average.
416 if (Options["UCI_AnalyseMode"].value<bool>())
417 Weights[kingDangerUs] = Weights[kingDangerThem] = (Weights[kingDangerUs] + Weights[kingDangerThem]) / 2;
425 // init_eval_info() initializes king bitboards for given color adding
426 // pawn attacks. To be done at the beginning of the evaluation.
428 template<Color Us, bool HasPopCnt>
429 void init_eval_info(const Position& pos, EvalInfo& ei) {
431 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
432 const Color Them = (Us == WHITE ? BLACK : WHITE);
434 Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
435 ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
437 // Init king safety tables only if we are going to use them
438 if ( pos.piece_count(Us, QUEEN)
439 && pos.non_pawn_material(Us) >= QueenValueMidgame + RookValueMidgame)
441 ei.kingZone[Us] = (b | (Us == WHITE ? b >> 8 : b << 8));
442 b &= ei.attackedBy[Us][PAWN];
443 ei.kingAttackersCount[Us] = b ? count_1s<Max15>(b) / 2 : 0;
444 ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
446 ei.kingZone[Us] = ei.kingAttackersCount[Us] = 0;
450 // evaluate_outposts() evaluates bishop and knight outposts squares
452 template<PieceType Piece, Color Us>
453 Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
455 const Color Them = (Us == WHITE ? BLACK : WHITE);
457 assert (Piece == BISHOP || Piece == KNIGHT);
459 // Initial bonus based on square
460 Value bonus = OutpostBonus[Piece == BISHOP][relative_square(Us, s)];
462 // Increase bonus if supported by pawn, especially if the opponent has
463 // no minor piece which can exchange the outpost piece.
464 if (bonus && bit_is_set(ei.attackedBy[Us][PAWN], s))
466 if ( pos.pieces(KNIGHT, Them) == EmptyBoardBB
467 && (SquaresByColorBB[square_color(s)] & pos.pieces(BISHOP, Them)) == EmptyBoardBB)
468 bonus += bonus + bonus / 2;
472 return make_score(bonus, bonus);
476 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
478 template<PieceType Piece, Color Us, bool HasPopCnt, bool Trace>
479 Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
485 Score score = SCORE_ZERO;
487 const BitCountType Full = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64 : CNT32;
488 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
489 const Color Them = (Us == WHITE ? BLACK : WHITE);
490 const Square* ptr = pos.piece_list_begin(Us, Piece);
492 ei.attackedBy[Us][Piece] = EmptyBoardBB;
494 while ((s = *ptr++) != SQ_NONE)
496 // Find attacked squares, including x-ray attacks for bishops and rooks
497 if (Piece == KNIGHT || Piece == QUEEN)
498 b = pos.attacks_from<Piece>(s);
499 else if (Piece == BISHOP)
500 b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
501 else if (Piece == ROOK)
502 b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
506 // Update attack info
507 ei.attackedBy[Us][Piece] |= b;
510 if (b & ei.kingZone[Us])
512 ei.kingAttackersCount[Us]++;
513 ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
514 Bitboard bb = (b & ei.attackedBy[Them][KING]);
516 ei.kingAdjacentZoneAttacksCount[Us] += count_1s<Max15>(bb);
520 mob = (Piece != QUEEN ? count_1s<Max15>(b & mobilityArea)
521 : count_1s<Full >(b & mobilityArea));
523 mobility += MobilityBonus[Piece][mob];
525 // Decrease score if we are attacked by an enemy pawn. Remaining part
526 // of threat evaluation must be done later when we have full attack info.
527 if (bit_is_set(ei.attackedBy[Them][PAWN], s))
528 score -= ThreatedByPawnPenalty[Piece];
530 // Bishop and knight outposts squares
531 if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Us))
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) + (square_file(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 ( square_file(ksq) >= FILE_E
584 && square_file(s) > square_file(ksq)
585 && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(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, square_file(ksq)))
589 score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
590 : (TrappedRookPenalty - mob * 16), 0);
592 else if ( square_file(ksq) <= FILE_D
593 && square_file(s) < square_file(ksq)
594 && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(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, square_file(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_of_color(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_of_color(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 = 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_of_color(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_of_color(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_of_color(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 = Min(99, 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(Us), blockSq) * 3 * rr);
817 ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
818 ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 6 * rr);
820 // If the pawn is free to advance, increase bonus
821 if (pos.square_is_empty(blockSq))
823 squaresToQueen = squares_in_front_of(Us, s);
824 defendedSquares = squaresToQueen & ei.attackedBy[Us][0];
826 // If there is an enemy rook or queen attacking the pawn from behind,
827 // add all X-ray attacks by the rook or queen. Otherwise consider only
828 // the squares in the pawn's path attacked or occupied by the enemy.
829 if ( (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them))
830 && (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from<ROOK>(s)))
831 unsafeSquares = squaresToQueen;
833 unsafeSquares = squaresToQueen & (ei.attackedBy[Them][0] | pos.pieces_of_color(Them));
835 // If there aren't enemy attacks or pieces along the path to queen give
836 // huge bonus. Even bigger if we protect the pawn's path.
838 ebonus += Value(rr * (squaresToQueen == defendedSquares ? 17 : 15));
840 // OK, there are enemy attacks or pieces (but not pawns). Are those
841 // squares which are attacked by the enemy also attacked by us ?
842 // If yes, big bonus (but smaller than when there are no enemy attacks),
843 // if no, somewhat smaller bonus.
844 ebonus += Value(rr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8));
846 // At last, add a small bonus when there are no *friendly* pieces
847 // in the pawn's path.
848 if (!(squaresToQueen & pos.pieces_of_color(Us)))
853 // Increase the bonus if the passed pawn is supported by a friendly pawn
854 // on the same rank and a bit smaller if it's on the previous rank.
855 supportingPawns = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
856 if (supportingPawns & rank_bb(s))
857 ebonus += Value(r * 20);
858 else if (supportingPawns & rank_bb(s - pawn_push(Us)))
859 ebonus += Value(r * 12);
861 // Rook pawns are a special case: They are sometimes worse, and
862 // sometimes better than other passed pawns. It is difficult to find
863 // good rules for determining whether they are good or bad. For now,
864 // we try the following: Increase the value for rook pawns if the
865 // other side has no pieces apart from a knight, and decrease the
866 // value if the other side has a rook or queen.
867 if (square_file(s) == FILE_A || square_file(s) == FILE_H)
869 if (pos.non_pawn_material(Them) <= KnightValueMidgame)
870 ebonus += ebonus / 4;
871 else if (pos.pieces(ROOK, QUEEN, Them))
872 ebonus -= ebonus / 4;
874 score += make_score(mbonus, ebonus);
878 // Add the scores to the middle game and endgame eval
879 return apply_weight(score, Weights[PassedPawns]);
883 // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides, this is quite
884 // conservative and returns a winning score only when we are very sure that the pawn is winning.
886 template<bool HasPopCnt>
887 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
889 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
891 Bitboard b, b2, blockers, supporters, queeningPath, candidates;
892 Square s, blockSq, queeningSquare;
893 Color c, winnerSide, loserSide;
894 bool pathDefended, opposed;
895 int pliesToGo, movesToGo, oppMovesToGo, sacptg, blockersCount, minKingDist, kingptg, d;
896 int pliesToQueen[] = { 256, 256 };
898 // Step 1. Hunt for unstoppable passed pawns. If we find at least one,
899 // record how many plies are required for promotion.
900 for (c = WHITE; c <= BLACK; c++)
902 // Skip if other side has non-pawn pieces
903 if (pos.non_pawn_material(opposite_color(c)))
906 b = ei.pi->passed_pawns(c);
911 queeningSquare = relative_square(c, make_square(square_file(s), RANK_8));
912 queeningPath = squares_in_front_of(c, s);
914 // Compute plies to queening and check direct advancement
915 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(c, s) == RANK_2);
916 oppMovesToGo = square_distance(pos.king_square(opposite_color(c)), queeningSquare) - int(c != pos.side_to_move());
917 pathDefended = ((ei.attackedBy[c][0] & queeningPath) == queeningPath);
919 if (movesToGo >= oppMovesToGo && !pathDefended)
922 // Opponent king cannot block because path is defended and position
923 // is not in check. So only friendly pieces can be blockers.
924 assert(!pos.in_check());
925 assert(queeningPath & pos.occupied_squares() == queeningPath & pos.pieces_of_color(c));
927 // Add moves needed to free the path from friendly pieces and retest condition
928 movesToGo += count_1s<Max15>(queeningPath & pos.pieces_of_color(c));
930 if (movesToGo >= oppMovesToGo && !pathDefended)
933 pliesToGo = 2 * movesToGo - int(c == pos.side_to_move());
934 pliesToQueen[c] = Min(pliesToQueen[c], pliesToGo);
938 // Step 2. If either side cannot promote at least three plies before the other side then situation
939 // becomes too complex and we give up. Otherwise we determine the possibly "winning side"
940 if (abs(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3)
943 winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK);
944 loserSide = opposite_color(winnerSide);
946 // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
947 b = candidates = pos.pieces(PAWN, loserSide);
953 // Compute plies from queening
954 queeningSquare = relative_square(loserSide, make_square(square_file(s), RANK_8));
955 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
956 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
958 // Check if (without even considering any obstacles) we're too far away or doubled
959 if ( pliesToQueen[winnerSide] + 3 <= pliesToGo
960 || (squares_in_front_of(loserSide, s) & pos.pieces(PAWN, loserSide)))
961 clear_bit(&candidates, s);
964 // If any candidate is already a passed pawn it _may_ promote in time. We give up.
965 if (candidates & ei.pi->passed_pawns(loserSide))
968 // Step 4. Check new passed pawn creation through king capturing and pawn sacrifices
974 sacptg = blockersCount = 0;
975 minKingDist = kingptg = 256;
977 // Compute plies from queening
978 queeningSquare = relative_square(loserSide, make_square(square_file(s), RANK_8));
979 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
980 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
982 // Generate list of blocking pawns and supporters
983 supporters = neighboring_files_bb(s) & candidates;
984 opposed = squares_in_front_of(loserSide, s) & pos.pieces(PAWN, winnerSide);
985 blockers = passed_pawn_mask(loserSide, s) & pos.pieces(PAWN, winnerSide);
989 // How many plies does it take to remove all the blocking pawns?
992 blockSq = pop_1st_bit(&blockers);
995 // Check pawns that can give support to overcome obstacle, for instance
996 // black pawns: a4, b4 white: b2 then pawn in b4 is giving support.
999 b2 = supporters & in_front_bb(winnerSide, blockSq + pawn_push(winnerSide));
1001 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1003 d = square_distance(blockSq, pop_1st_bit(&b2)) - 2;
1004 movesToGo = Min(movesToGo, d);
1008 // Check pawns that can be sacrificed against the blocking pawn
1009 b2 = attack_span_mask(winnerSide, blockSq) & candidates & ~(1ULL << s);
1011 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1013 d = square_distance(blockSq, pop_1st_bit(&b2)) - 2;
1014 movesToGo = Min(movesToGo, d);
1017 // If obstacle can be destroyed with an immediate pawn exchange / sacrifice,
1018 // it's not a real obstacle and we have nothing to add to pliesToGo.
1022 // Plies needed to sacrifice against all the blocking pawns
1023 sacptg += movesToGo * 2;
1026 // Plies needed for the king to capture all the blocking pawns
1027 d = square_distance(pos.king_square(loserSide), blockSq);
1028 minKingDist = Min(minKingDist, d);
1029 kingptg = (minKingDist + blockersCount) * 2;
1032 // Check if pawn sacrifice plan _may_ save the day
1033 if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg)
1036 // Check if king capture plan _may_ save the day (contains some false positives)
1037 if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg)
1041 // Winning pawn is unstoppable and will promote as first, return big score
1042 Score score = make_score(0, (Value) 0x500 - 0x20 * pliesToQueen[winnerSide]);
1043 return winnerSide == WHITE ? score : -score;
1047 // evaluate_space() computes the space evaluation for a given side. The
1048 // space evaluation is a simple bonus based on the number of safe squares
1049 // available for minor pieces on the central four files on ranks 2--4. Safe
1050 // squares one, two or three squares behind a friendly pawn are counted
1051 // twice. Finally, the space bonus is scaled by a weight taken from the
1052 // material hash table. The aim is to improve play on game opening.
1053 template<Color Us, bool HasPopCnt>
1054 int evaluate_space(const Position& pos, EvalInfo& ei) {
1056 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
1057 const Color Them = (Us == WHITE ? BLACK : WHITE);
1059 // Find the safe squares for our pieces inside the area defined by
1060 // SpaceMask[]. A square is unsafe if it is attacked by an enemy
1061 // pawn, or if it is undefended and attacked by an enemy piece.
1062 Bitboard safe = SpaceMask[Us]
1063 & ~pos.pieces(PAWN, Us)
1064 & ~ei.attackedBy[Them][PAWN]
1065 & (ei.attackedBy[Us][0] | ~ei.attackedBy[Them][0]);
1067 // Find all squares which are at most three squares behind some friendly pawn
1068 Bitboard behind = pos.pieces(PAWN, Us);
1069 behind |= (Us == WHITE ? behind >> 8 : behind << 8);
1070 behind |= (Us == WHITE ? behind >> 16 : behind << 16);
1072 return count_1s<Max15>(safe) + count_1s<Max15>(behind & safe);
1076 // apply_weight() applies an evaluation weight to a value trying to prevent overflow
1078 inline Score apply_weight(Score v, Score w) {
1079 return make_score((int(mg_value(v)) * mg_value(w)) / 0x100,
1080 (int(eg_value(v)) * eg_value(w)) / 0x100);
1084 // scale_by_game_phase() interpolates between a middle game and an endgame score,
1085 // based on game phase. It also scales the return value by a ScaleFactor array.
1087 Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf) {
1089 assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
1090 assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
1091 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1093 int ev = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
1094 int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128;
1095 return Value((result + GrainSize / 2) & ~(GrainSize - 1));
1099 // weight_option() computes the value of an evaluation weight, by combining
1100 // two UCI-configurable weights (midgame and endgame) with an internal weight.
1102 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
1104 // Scale option value from 100 to 256
1105 int mg = Options[mgOpt].value<int>() * 256 / 100;
1106 int eg = Options[egOpt].value<int>() * 256 / 100;
1108 return apply_weight(make_score(mg, eg), internalWeight);
1112 // init_safety() initizes the king safety evaluation, based on UCI
1113 // parameters. It is called from read_weights().
1115 void init_safety() {
1117 const Value MaxSlope = Value(30);
1118 const Value Peak = Value(1280);
1121 // First setup the base table
1122 for (int i = 0; i < 100; i++)
1124 t[i] = Value(int(0.4 * i * i));
1127 t[i] = Min(t[i], t[i - 1] + MaxSlope);
1129 t[i] = Min(t[i], Peak);
1132 // Then apply the weights and get the final KingDangerTable[] array
1133 for (Color c = WHITE; c <= BLACK; c++)
1134 for (int i = 0; i < 100; i++)
1135 KingDangerTable[c][i] = apply_weight(make_score(t[i], 0), Weights[KingDangerUs + c]);
1139 // A couple of little helpers used by tracing code, to_cp() converts a value to
1140 // a double in centipawns scale, trace_add() stores white and black scores.
1142 double to_cp(Value v) { return double(v) / double(PawnValueMidgame); }
1144 void trace_add(int idx, Score wScore, Score bScore) {
1146 TracedScores[WHITE][idx] = wScore;
1147 TracedScores[BLACK][idx] = bScore;
1150 // trace_row() is an helper function used by tracing code to register the
1151 // values of a single evaluation term.
1153 void trace_row(const char *name, int idx) {
1155 Score wScore = TracedScores[WHITE][idx];
1156 Score bScore = TracedScores[BLACK][idx];
1159 case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL:
1160 TraceStream << std::setw(20) << name << " | --- --- | --- --- | "
1161 << std::setw(6) << to_cp(mg_value(wScore)) << " "
1162 << std::setw(6) << to_cp(eg_value(wScore)) << " \n";
1165 TraceStream << std::setw(20) << name << " | " << std::noshowpos
1166 << std::setw(5) << to_cp(mg_value(wScore)) << " "
1167 << std::setw(5) << to_cp(eg_value(wScore)) << " | "
1168 << std::setw(5) << to_cp(mg_value(bScore)) << " "
1169 << std::setw(5) << to_cp(eg_value(bScore)) << " | "
1171 << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " "
1172 << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n";
1178 /// trace_evaluate() is like evaluate() but instead of a value returns a string
1179 /// suitable to be print on stdout with the detailed descriptions and values of
1180 /// each evaluation term. Used mainly for debugging.
1182 std::string trace_evaluate(const Position& pos) {
1187 TraceStream.str("");
1188 TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
1189 memset(TracedScores, 0, 2 * 16 * sizeof(Score));
1191 do_evaluate<false, true>(pos, margin);
1193 totals = TraceStream.str();
1194 TraceStream.str("");
1196 TraceStream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
1197 << " | MG EG | MG EG | MG EG \n"
1198 << "---------------------+-------------+-------------+---------------\n";
1200 trace_row("Material, PST, Tempo", PST);
1201 trace_row("Material imbalance", IMBALANCE);
1202 trace_row("Pawns", PAWN);
1203 trace_row("Knights", KNIGHT);
1204 trace_row("Bishops", BISHOP);
1205 trace_row("Rooks", ROOK);
1206 trace_row("Queens", QUEEN);
1207 trace_row("Mobility", MOBILITY);
1208 trace_row("King safety", KING);
1209 trace_row("Threats", THREAT);
1210 trace_row("Passed pawns", PASSED);
1211 trace_row("Unstoppable pawns", UNSTOPPABLE);
1212 trace_row("Space", SPACE);
1214 TraceStream << "---------------------+-------------+-------------+---------------\n";
1215 trace_row("Total", TOTAL);
1216 TraceStream << totals;
1218 return TraceStream.str();