2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2013 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][ALL_PIECES]
44 // contains all squares attacked by the given color.
45 Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB];
47 // kingRing[color] is the zone around the 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, kingRing[BLACK] is a bitboard containing the squares f8, h8,
52 // f7, g7, h7, f6, g6 and h6.
53 Bitboard kingRing[COLOR_NB];
55 // kingAttackersCount[color] is the number of pieces of the given color
56 // which attack a square in the kingRing of the enemy king.
57 int kingAttackersCount[COLOR_NB];
59 // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
60 // given color which attack a square in the kingRing 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[COLOR_NB];
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[COLOR_NB];
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, 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(289, 344), S(221, 273), S(46, 0), S(271, 0), S(307, 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[][SQUARE_NB] = {
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[][PIECE_TYPE_NB] = {
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( 0, 22), 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 // ThreatenedByPawnPenalty[PieceType] contains a penalty according to which
146 // piece type is attacked by an enemy pawn.
147 const Score ThreatenedByPawnPenalty[] = {
148 S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
153 const Score BishopPinBonus = make_score(66, 11);
155 // Bonus for having the side to move (modified by Joona Kiiski)
156 const Score Tempo = make_score(24, 11);
158 // Rooks and queens on the 7th rank
159 const Score RookOn7thBonus = make_score(3, 20);
160 const Score QueenOn7thBonus = make_score(1, 8);
162 // Rooks and queens attacking pawns on the same rank
163 const Score RookOnPawnBonus = make_score(3, 48);
164 const Score QueenOnPawnBonus = make_score(1, 40);
166 // Rooks on open files (modified by Joona Kiiski)
167 const Score RookOpenFileBonus = make_score(43, 21);
168 const Score RookHalfOpenFileBonus = make_score(19, 10);
170 // Penalty for rooks trapped inside a friendly king which has lost the
172 const Value TrappedRookPenalty = Value(180);
174 // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
175 // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
176 // happen in Chess960 games.
177 const Score TrappedBishopA1H1Penalty = make_score(100, 100);
179 // Penalty for an undefended bishop or knight
180 const Score UndefendedMinorPenalty = make_score(25, 10);
182 // The SpaceMask[Color] contains the area of the board which is considered
183 // by the space evaluation. In the middle game, each side is given a bonus
184 // based on how many squares inside this area are safe and available for
185 // friendly minor pieces.
186 const Bitboard SpaceMask[] = {
187 (1ULL << SQ_C2) | (1ULL << SQ_D2) | (1ULL << SQ_E2) | (1ULL << SQ_F2) |
188 (1ULL << SQ_C3) | (1ULL << SQ_D3) | (1ULL << SQ_E3) | (1ULL << SQ_F3) |
189 (1ULL << SQ_C4) | (1ULL << SQ_D4) | (1ULL << SQ_E4) | (1ULL << SQ_F4),
190 (1ULL << SQ_C7) | (1ULL << SQ_D7) | (1ULL << SQ_E7) | (1ULL << SQ_F7) |
191 (1ULL << SQ_C6) | (1ULL << SQ_D6) | (1ULL << SQ_E6) | (1ULL << SQ_F6) |
192 (1ULL << SQ_C5) | (1ULL << SQ_D5) | (1ULL << SQ_E5) | (1ULL << SQ_F5)
195 // King danger constants and variables. The king danger scores are taken
196 // from the KingDangerTable[]. Various little "meta-bonuses" measuring
197 // the strength of the enemy attack are added up into an integer, which
198 // is used as an index to KingDangerTable[].
200 // KingAttackWeights[PieceType] contains king attack weights by piece type
201 const int KingAttackWeights[] = { 0, 0, 2, 2, 3, 5 };
203 // Bonuses for enemy's safe checks
204 const int QueenContactCheckBonus = 6;
205 const int RookContactCheckBonus = 4;
206 const int QueenCheckBonus = 3;
207 const int RookCheckBonus = 2;
208 const int BishopCheckBonus = 1;
209 const int KnightCheckBonus = 1;
211 // InitKingDanger[Square] contains penalties based on the position of the
212 // defending king, indexed by king's square (from white's point of view).
213 const int InitKingDanger[] = {
214 2, 0, 2, 5, 5, 2, 0, 2,
215 2, 2, 4, 8, 8, 4, 2, 2,
216 7, 10, 12, 12, 12, 12, 10, 7,
217 15, 15, 15, 15, 15, 15, 15, 15,
218 15, 15, 15, 15, 15, 15, 15, 15,
219 15, 15, 15, 15, 15, 15, 15, 15,
220 15, 15, 15, 15, 15, 15, 15, 15,
221 15, 15, 15, 15, 15, 15, 15, 15
224 // KingDangerTable[Color][attackUnits] contains the actual king danger
225 // weighted scores, indexed by color and by a calculated integer number.
226 Score KingDangerTable[COLOR_NB][128];
228 // TracedTerms[Color][PieceType || TracedType] contains a breakdown of the
229 // evaluation terms, used when tracing.
230 Score TracedScores[COLOR_NB][16];
231 std::stringstream TraceStream;
234 PST = 8, IMBALANCE = 9, MOBILITY = 10, THREAT = 11,
235 PASSED = 12, UNSTOPPABLE = 13, SPACE = 14, TOTAL = 15
238 // Function prototypes
240 Value do_evaluate(const Position& pos, Value& margin);
243 void init_eval_info(const Position& pos, EvalInfo& ei);
245 template<Color Us, bool Trace>
246 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility);
248 template<Color Us, bool Trace>
249 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]);
252 Score evaluate_threats(const Position& pos, EvalInfo& ei);
255 int evaluate_space(const Position& pos, EvalInfo& ei);
258 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
260 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
262 Value interpolate(const Score& v, Phase ph, ScaleFactor sf);
263 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
264 double to_cp(Value v);
265 void trace_add(int idx, Score term_w, Score term_b = SCORE_ZERO);
266 void trace_row(const char* name, int idx);
272 /// evaluate() is the main evaluation function. It always computes two
273 /// values, an endgame score and a middle game score, and interpolates
274 /// between them based on the remaining material.
276 Value evaluate(const Position& pos, Value& margin) {
277 return do_evaluate<false>(pos, margin);
281 /// init() computes evaluation weights from the corresponding UCI parameters
282 /// and setup king tables.
286 Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
287 Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
288 Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
289 Weights[KingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
290 Weights[KingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
292 const int MaxSlope = 30;
293 const int Peak = 1280;
295 for (int t = 0, i = 1; i < 100; i++)
297 t = std::min(Peak, std::min(int(0.4 * i * i), t + MaxSlope));
299 KingDangerTable[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]);
300 KingDangerTable[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]);
305 /// trace() is like evaluate() but instead of a value returns a string suitable
306 /// to be print on stdout with the detailed descriptions and values of each
307 /// evaluation term. Used mainly for debugging.
309 std::string trace(const Position& pos) {
314 Search::RootColor = pos.side_to_move();
317 TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
318 memset(TracedScores, 0, 2 * 16 * sizeof(Score));
320 do_evaluate<true>(pos, margin);
322 totals = TraceStream.str();
325 TraceStream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
326 << " | MG EG | MG EG | MG EG \n"
327 << "---------------------+-------------+-------------+---------------\n";
329 trace_row("Material, PST, Tempo", PST);
330 trace_row("Material imbalance", IMBALANCE);
331 trace_row("Pawns", PAWN);
332 trace_row("Knights", KNIGHT);
333 trace_row("Bishops", BISHOP);
334 trace_row("Rooks", ROOK);
335 trace_row("Queens", QUEEN);
336 trace_row("Mobility", MOBILITY);
337 trace_row("King safety", KING);
338 trace_row("Threats", THREAT);
339 trace_row("Passed pawns", PASSED);
340 trace_row("Unstoppable pawns", UNSTOPPABLE);
341 trace_row("Space", SPACE);
343 TraceStream << "---------------------+-------------+-------------+---------------\n";
344 trace_row("Total", TOTAL);
345 TraceStream << totals;
347 return TraceStream.str();
356 Value do_evaluate(const Position& pos, Value& margin) {
358 assert(!pos.checkers());
361 Value margins[COLOR_NB];
362 Score score, mobilityWhite, mobilityBlack;
363 Thread* th = pos.this_thread();
365 // margins[] store the uncertainty estimation of position's evaluation
366 // that typically is used by the search for pruning decisions.
367 margins[WHITE] = margins[BLACK] = VALUE_ZERO;
369 // Initialize score by reading the incrementally updated scores included
370 // in the position object (material + piece square tables) and adding
371 // Tempo bonus. Score is computed from the point of view of white.
372 score = pos.psq_score() + (pos.side_to_move() == WHITE ? Tempo : -Tempo);
374 // Probe the material hash table
375 ei.mi = Material::probe(pos, th->materialTable, th->endgames);
376 score += ei.mi->material_value();
378 // If we have a specialized evaluation function for the current material
379 // configuration, call it and return.
380 if (ei.mi->specialized_eval_exists())
383 return ei.mi->evaluate(pos);
386 // Probe the pawn hash table
387 ei.pi = Pawns::probe(pos, th->pawnsTable);
388 score += ei.pi->pawns_value();
390 // Initialize attack and king safety bitboards
391 init_eval_info<WHITE>(pos, ei);
392 init_eval_info<BLACK>(pos, ei);
394 // Evaluate pieces and mobility
395 score += evaluate_pieces_of_color<WHITE, Trace>(pos, ei, mobilityWhite)
396 - evaluate_pieces_of_color<BLACK, Trace>(pos, ei, mobilityBlack);
398 score += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
400 // Evaluate kings after all other pieces because we need complete attack
401 // information when computing the king safety evaluation.
402 score += evaluate_king<WHITE, Trace>(pos, ei, margins)
403 - evaluate_king<BLACK, Trace>(pos, ei, margins);
405 // Evaluate tactical threats, we need full attack information including king
406 score += evaluate_threats<WHITE>(pos, ei)
407 - evaluate_threats<BLACK>(pos, ei);
409 // Evaluate passed pawns, we need full attack information including king
410 score += evaluate_passed_pawns<WHITE>(pos, ei)
411 - evaluate_passed_pawns<BLACK>(pos, ei);
413 // If one side has only a king, check whether exists any unstoppable passed pawn
414 if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
415 score += evaluate_unstoppable_pawns(pos, ei);
417 // Evaluate space for both sides, only in middle-game.
418 if (ei.mi->space_weight())
420 int s = evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei);
421 score += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]);
424 // Scale winning side if position is more drawish that what it appears
425 ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE)
426 : ei.mi->scale_factor(pos, BLACK);
428 // If we don't already have an unusual scale factor, check for opposite
429 // colored bishop endgames, and use a lower scale for those.
430 if ( ei.mi->game_phase() < PHASE_MIDGAME
431 && pos.opposite_bishops()
432 && sf == SCALE_FACTOR_NORMAL)
434 // Only the two bishops ?
435 if ( pos.non_pawn_material(WHITE) == BishopValueMg
436 && pos.non_pawn_material(BLACK) == BishopValueMg)
438 // Check for KBP vs KB with only a single pawn that is almost
439 // certainly a draw or at least two pawns.
440 bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
441 sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
444 // Endgame with opposite-colored bishops, but also other pieces. Still
445 // a bit drawish, but not as drawish as with only the two bishops.
446 sf = ScaleFactor(50);
449 margin = margins[pos.side_to_move()];
450 Value v = interpolate(score, ei.mi->game_phase(), sf);
452 // In case of tracing add all single evaluation contributions for both white and black
455 trace_add(PST, pos.psq_score());
456 trace_add(IMBALANCE, ei.mi->material_value());
457 trace_add(PAWN, ei.pi->pawns_value());
458 trace_add(MOBILITY, apply_weight(mobilityWhite, Weights[Mobility]), apply_weight(mobilityBlack, Weights[Mobility]));
459 trace_add(THREAT, evaluate_threats<WHITE>(pos, ei), evaluate_threats<BLACK>(pos, ei));
460 trace_add(PASSED, evaluate_passed_pawns<WHITE>(pos, ei), evaluate_passed_pawns<BLACK>(pos, ei));
461 trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns(pos, ei));
462 Score w = make_score(ei.mi->space_weight() * evaluate_space<WHITE>(pos, ei), 0);
463 Score b = make_score(ei.mi->space_weight() * evaluate_space<BLACK>(pos, ei), 0);
464 trace_add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
465 trace_add(TOTAL, score);
466 TraceStream << "\nUncertainty margin: White: " << to_cp(margins[WHITE])
467 << ", Black: " << to_cp(margins[BLACK])
468 << "\nScaling: " << std::noshowpos
469 << std::setw(6) << 100.0 * ei.mi->game_phase() / 128.0 << "% MG, "
470 << std::setw(6) << 100.0 * (1.0 - ei.mi->game_phase() / 128.0) << "% * "
471 << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
472 << "Total evaluation: " << to_cp(v);
475 return pos.side_to_move() == WHITE ? v : -v;
479 // init_eval_info() initializes king bitboards for given color adding
480 // pawn attacks. To be done at the beginning of the evaluation.
483 void init_eval_info(const Position& pos, EvalInfo& ei) {
485 const Color Them = (Us == WHITE ? BLACK : WHITE);
487 Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
488 ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
490 // Init king safety tables only if we are going to use them
491 if ( pos.piece_count(Us, QUEEN)
492 && pos.non_pawn_material(Us) > QueenValueMg + PawnValueMg)
494 ei.kingRing[Them] = (b | (Us == WHITE ? b >> 8 : b << 8));
495 b &= ei.attackedBy[Us][PAWN];
496 ei.kingAttackersCount[Us] = b ? popcount<Max15>(b) / 2 : 0;
497 ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
499 ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0;
503 // evaluate_outposts() evaluates bishop and knight outposts squares
505 template<PieceType Piece, Color Us>
506 Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
508 const Color Them = (Us == WHITE ? BLACK : WHITE);
510 assert (Piece == BISHOP || Piece == KNIGHT);
512 // Initial bonus based on square
513 Value bonus = OutpostBonus[Piece == BISHOP][relative_square(Us, s)];
515 // Increase bonus if supported by pawn, especially if the opponent has
516 // no minor piece which can exchange the outpost piece.
517 if (bonus && (ei.attackedBy[Us][PAWN] & s))
519 if ( !pos.pieces(Them, KNIGHT)
520 && !(same_color_squares(s) & pos.pieces(Them, BISHOP)))
521 bonus += bonus + bonus / 2;
525 return make_score(bonus, bonus);
529 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
531 template<PieceType Piece, Color Us, bool Trace>
532 Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
538 Score score = SCORE_ZERO;
540 const Color Them = (Us == WHITE ? BLACK : WHITE);
541 const Square* pl = pos.piece_list(Us, Piece);
543 ei.attackedBy[Us][Piece] = 0;
545 while ((s = *pl++) != SQ_NONE)
547 // Find attacked squares, including x-ray attacks for bishops and rooks
548 if (Piece == KNIGHT || Piece == QUEEN)
549 b = pos.attacks_from<Piece>(s);
550 else if (Piece == BISHOP)
551 b = attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(Us, QUEEN));
552 else if (Piece == ROOK)
553 b = attacks_bb<ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN));
557 ei.attackedBy[Us][Piece] |= b;
559 if (b & ei.kingRing[Them])
561 ei.kingAttackersCount[Us]++;
562 ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
563 Bitboard bb = (b & ei.attackedBy[Them][KING]);
565 ei.kingAdjacentZoneAttacksCount[Us] += popcount<Max15>(bb);
568 mob = (Piece != QUEEN ? popcount<Max15>(b & mobilityArea)
569 : popcount<Full >(b & mobilityArea));
571 mobility += MobilityBonus[Piece][mob];
573 // Decrease score if we are attacked by an enemy pawn. Remaining part
574 // of threat evaluation must be done later when we have full attack info.
575 if (ei.attackedBy[Them][PAWN] & s)
576 score -= ThreatenedByPawnPenalty[Piece];
578 // Otherwise give a bonus if we are a bishop and can pin a piece or
579 // can give a discovered check through an x-ray attack.
580 else if ( Piece == BISHOP
581 && (PseudoAttacks[Piece][pos.king_square(Them)] & s)
582 && !more_than_one(BetweenBB[s][pos.king_square(Them)] & pos.pieces()))
583 score += BishopPinBonus;
585 // Penalty for bishop with same coloured pawns
587 score -= make_score(4, 4) * ei.pi->same_colored_pawn_count(s, Us);
589 // Bishop and knight outposts squares
590 if ( (Piece == BISHOP || Piece == KNIGHT)
591 && !(pos.pieces(Them, PAWN) & attack_span_mask(Us, s)))
592 score += evaluate_outposts<Piece, Us>(pos, ei, s);
594 if ((Piece == ROOK || Piece == QUEEN) && relative_rank(Us, s) >= RANK_5)
596 // Major piece on 7th rank
597 if ( relative_rank(Us, s) == RANK_7
598 && relative_rank(Us, pos.king_square(Them)) == RANK_8)
599 score += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
601 // Major piece attacking pawns on the same rank
602 Bitboard pawns = pos.pieces(Them, PAWN) & rank_bb(s);
604 score += (Piece == ROOK ? RookOnPawnBonus
605 : QueenOnPawnBonus) * popcount<Max15>(pawns);
608 // Special extra evaluation for bishops
609 if (Piece == BISHOP && pos.is_chess960())
611 // An important Chess960 pattern: A cornered bishop blocked by
612 // a friendly pawn diagonally in front of it is a very serious
613 // problem, especially when that pawn is also blocked.
614 if (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1))
616 Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
617 if (pos.piece_on(s + d) == make_piece(Us, PAWN))
619 if (!pos.is_empty(s + d + pawn_push(Us)))
620 score -= 2*TrappedBishopA1H1Penalty;
621 else if (pos.piece_on(s + 2*d) == make_piece(Us, PAWN))
622 score -= TrappedBishopA1H1Penalty;
624 score -= TrappedBishopA1H1Penalty / 2;
629 // Special extra evaluation for rooks
632 // Open and half-open files
634 if (ei.pi->file_is_half_open(Us, f))
636 if (ei.pi->file_is_half_open(Them, f))
637 score += RookOpenFileBonus;
639 score += RookHalfOpenFileBonus;
642 // Penalize rooks which are trapped inside a king. Penalize more if
643 // king has lost right to castle.
644 if (mob > 6 || ei.pi->file_is_half_open(Us, f))
647 ksq = pos.king_square(Us);
649 if ( file_of(ksq) >= FILE_E
650 && file_of(s) > file_of(ksq)
651 && (relative_rank(Us, ksq) == RANK_1 || rank_of(ksq) == rank_of(s)))
653 // Is there a half-open file between the king and the edge of the board?
654 if (!ei.pi->has_open_file_to_right(Us, file_of(ksq)))
655 score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
656 : (TrappedRookPenalty - mob * 16), 0);
658 else if ( file_of(ksq) <= FILE_D
659 && file_of(s) < file_of(ksq)
660 && (relative_rank(Us, ksq) == RANK_1 || rank_of(ksq) == rank_of(s)))
662 // Is there a half-open file between the king and the edge of the board?
663 if (!ei.pi->has_open_file_to_left(Us, file_of(ksq)))
664 score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
665 : (TrappedRookPenalty - mob * 16), 0);
671 TracedScores[Us][Piece] = score;
677 // evaluate_threats<>() assigns bonuses according to the type of attacking piece
678 // and the type of attacked one.
681 Score evaluate_threats(const Position& pos, EvalInfo& ei) {
683 const Color Them = (Us == WHITE ? BLACK : WHITE);
685 Bitboard b, undefendedMinors, weakEnemies;
686 Score score = SCORE_ZERO;
688 // Undefended minors get penalized even if not under attack
689 undefendedMinors = pos.pieces(Them)
690 & (pos.pieces(BISHOP) | pos.pieces(KNIGHT))
691 & ~ei.attackedBy[Them][ALL_PIECES];
693 if (undefendedMinors)
694 score += UndefendedMinorPenalty;
696 // Enemy pieces not defended by a pawn and under our attack
697 weakEnemies = pos.pieces(Them)
698 & ~ei.attackedBy[Them][PAWN]
699 & ei.attackedBy[Us][ALL_PIECES];
704 // Add bonus according to type of attacked enemy piece and to the
705 // type of attacking piece, from knights to queens. Kings are not
706 // considered because are already handled in king evaluation.
707 for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
709 b = ei.attackedBy[Us][pt1] & weakEnemies;
711 for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
712 if (b & pos.pieces(pt2))
713 score += ThreatBonus[pt1][pt2];
719 // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
720 // pieces of a given color.
722 template<Color Us, bool Trace>
723 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) {
725 const Color Them = (Us == WHITE ? BLACK : WHITE);
727 Score score = mobility = SCORE_ZERO;
729 // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
730 const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces(Us));
732 score += evaluate_pieces<KNIGHT, Us, Trace>(pos, ei, mobility, mobilityArea);
733 score += evaluate_pieces<BISHOP, Us, Trace>(pos, ei, mobility, mobilityArea);
734 score += evaluate_pieces<ROOK, Us, Trace>(pos, ei, mobility, mobilityArea);
735 score += evaluate_pieces<QUEEN, Us, Trace>(pos, ei, mobility, mobilityArea);
737 // Sum up all attacked squares
738 ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
739 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
740 | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
745 // evaluate_king<>() assigns bonuses and penalties to a king of a given color
747 template<Color Us, bool Trace>
748 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
750 const Color Them = (Us == WHITE ? BLACK : WHITE);
752 Bitboard undefended, b, b1, b2, safe;
754 const Square ksq = pos.king_square(Us);
756 // King shelter and enemy pawns storm
757 Score score = ei.pi->king_safety<Us>(pos, ksq);
759 // King safety. This is quite complicated, and is almost certainly far
760 // from optimally tuned.
761 if ( ei.kingAttackersCount[Them] >= 2
762 && ei.kingAdjacentZoneAttacksCount[Them])
764 // Find the attacked squares around the king which has no defenders
765 // apart from the king itself
766 undefended = ei.attackedBy[Them][ALL_PIECES] & ei.attackedBy[Us][KING];
767 undefended &= ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
768 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
769 | ei.attackedBy[Us][QUEEN]);
771 // Initialize the 'attackUnits' variable, which is used later on as an
772 // index to the KingDangerTable[] array. The initial value is based on
773 // the number and types of the enemy's attacking pieces, the number of
774 // attacked and undefended squares around our king, the square of the
775 // king, and the quality of the pawn shelter.
776 attackUnits = std::min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
777 + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount<Max15>(undefended))
778 + InitKingDanger[relative_square(Us, ksq)]
779 - mg_value(score) / 32;
781 // Analyse enemy's safe queen contact checks. First find undefended
782 // squares around the king attacked by enemy queen...
783 b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
786 // ...then remove squares not supported by another enemy piece
787 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
788 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
790 attackUnits += QueenContactCheckBonus
792 * (Them == pos.side_to_move() ? 2 : 1);
795 // Analyse enemy's safe rook contact checks. First find undefended
796 // squares around the king attacked by enemy rooks...
797 b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
799 // Consider only squares where the enemy rook gives check
800 b &= PseudoAttacks[ROOK][ksq];
804 // ...then remove squares not supported by another enemy piece
805 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
806 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]);
808 attackUnits += RookContactCheckBonus
810 * (Them == pos.side_to_move() ? 2 : 1);
813 // Analyse enemy's safe distance checks for sliders and knights
814 safe = ~(pos.pieces(Them) | ei.attackedBy[Us][ALL_PIECES]);
816 b1 = pos.attacks_from<ROOK>(ksq) & safe;
817 b2 = pos.attacks_from<BISHOP>(ksq) & safe;
819 // Enemy queen safe checks
820 b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
822 attackUnits += QueenCheckBonus * popcount<Max15>(b);
824 // Enemy rooks safe checks
825 b = b1 & ei.attackedBy[Them][ROOK];
827 attackUnits += RookCheckBonus * popcount<Max15>(b);
829 // Enemy bishops safe checks
830 b = b2 & ei.attackedBy[Them][BISHOP];
832 attackUnits += BishopCheckBonus * popcount<Max15>(b);
834 // Enemy knights safe checks
835 b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
837 attackUnits += KnightCheckBonus * popcount<Max15>(b);
839 // To index KingDangerTable[] attackUnits must be in [0, 99] range
840 attackUnits = std::min(99, std::max(0, attackUnits));
842 // Finally, extract the king danger score from the KingDangerTable[]
843 // array and subtract the score from evaluation. Set also margins[]
844 // value that will be used for pruning because this value can sometimes
845 // be very big, and so capturing a single attacking piece can therefore
846 // result in a score change far bigger than the value of the captured piece.
847 score -= KingDangerTable[Us == Search::RootColor][attackUnits];
848 margins[Us] += mg_value(KingDangerTable[Us == Search::RootColor][attackUnits]);
852 TracedScores[Us][KING] = score;
858 // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
861 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
863 const Color Them = (Us == WHITE ? BLACK : WHITE);
865 Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
866 Score score = SCORE_ZERO;
868 b = ei.pi->passed_pawns(Us);
874 Square s = pop_lsb(&b);
876 assert(pos.pawn_is_passed(Us, s));
878 int r = int(relative_rank(Us, s) - RANK_2);
879 int rr = r * (r - 1);
881 // Base bonus based on rank
882 Value mbonus = Value(20 * rr);
883 Value ebonus = Value(10 * (rr + r + 1));
887 Square blockSq = s + pawn_push(Us);
889 // Adjust bonus based on kings proximity
890 ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 5 * rr);
891 ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 2 * rr);
893 // If blockSq is not the queening square then consider also a second push
894 if (rank_of(blockSq) != (Us == WHITE ? RANK_8 : RANK_1))
895 ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
897 // If the pawn is free to advance, increase bonus
898 if (pos.is_empty(blockSq))
900 squaresToQueen = forward_bb(Us, s);
901 defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES];
903 // If there is an enemy rook or queen attacking the pawn from behind,
904 // add all X-ray attacks by the rook or queen. Otherwise consider only
905 // the squares in the pawn's path attacked or occupied by the enemy.
906 if ( (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN))
907 && (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN) & pos.attacks_from<ROOK>(s)))
908 unsafeSquares = squaresToQueen;
910 unsafeSquares = squaresToQueen & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
912 // If there aren't enemy attacks or pieces along the path to queen give
913 // huge bonus. Even bigger if we protect the pawn's path.
915 ebonus += Value(rr * (squaresToQueen == defendedSquares ? 17 : 15));
917 // OK, there are enemy attacks or pieces (but not pawns). Are those
918 // squares which are attacked by the enemy also attacked by us ?
919 // If yes, big bonus (but smaller than when there are no enemy attacks),
920 // if no, somewhat smaller bonus.
921 ebonus += Value(rr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8));
925 // Increase the bonus if the passed pawn is supported by a friendly pawn
926 // on the same rank and a bit smaller if it's on the previous rank.
927 supportingPawns = pos.pieces(Us, PAWN) & adjacent_files_bb(file_of(s));
928 if (supportingPawns & rank_bb(s))
929 ebonus += Value(r * 20);
931 else if (supportingPawns & rank_bb(s - pawn_push(Us)))
932 ebonus += Value(r * 12);
934 // Rook pawns are a special case: They are sometimes worse, and
935 // sometimes better than other passed pawns. It is difficult to find
936 // good rules for determining whether they are good or bad. For now,
937 // we try the following: Increase the value for rook pawns if the
938 // other side has no pieces apart from a knight, and decrease the
939 // value if the other side has a rook or queen.
940 if (file_of(s) == FILE_A || file_of(s) == FILE_H)
942 if (pos.non_pawn_material(Them) <= KnightValueMg)
943 ebonus += ebonus / 4;
944 else if (pos.pieces(Them, ROOK, QUEEN))
945 ebonus -= ebonus / 4;
947 score += make_score(mbonus, ebonus);
951 // Add the scores to the middle game and endgame eval
952 return apply_weight(score, Weights[PassedPawns]);
956 // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides, this is quite
957 // conservative and returns a winning score only when we are very sure that the pawn is winning.
959 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
961 Bitboard b, b2, blockers, supporters, queeningPath, candidates;
962 Square s, blockSq, queeningSquare;
963 Color c, winnerSide, loserSide;
964 bool pathDefended, opposed;
965 int pliesToGo, movesToGo, oppMovesToGo, sacptg, blockersCount, minKingDist, kingptg, d;
966 int pliesToQueen[] = { 256, 256 };
968 // Step 1. Hunt for unstoppable passed pawns. If we find at least one,
969 // record how many plies are required for promotion.
970 for (c = WHITE; c <= BLACK; c++)
972 // Skip if other side has non-pawn pieces
973 if (pos.non_pawn_material(~c))
976 b = ei.pi->passed_pawns(c);
981 queeningSquare = relative_square(c, file_of(s) | RANK_8);
982 queeningPath = forward_bb(c, s);
984 // Compute plies to queening and check direct advancement
985 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(c, s) == RANK_2);
986 oppMovesToGo = square_distance(pos.king_square(~c), queeningSquare) - int(c != pos.side_to_move());
987 pathDefended = ((ei.attackedBy[c][ALL_PIECES] & queeningPath) == queeningPath);
989 if (movesToGo >= oppMovesToGo && !pathDefended)
992 // Opponent king cannot block because path is defended and position
993 // is not in check. So only friendly pieces can be blockers.
994 assert(!pos.checkers());
995 assert((queeningPath & pos.pieces()) == (queeningPath & pos.pieces(c)));
997 // Add moves needed to free the path from friendly pieces and retest condition
998 movesToGo += popcount<Max15>(queeningPath & pos.pieces(c));
1000 if (movesToGo >= oppMovesToGo && !pathDefended)
1003 pliesToGo = 2 * movesToGo - int(c == pos.side_to_move());
1004 pliesToQueen[c] = std::min(pliesToQueen[c], pliesToGo);
1008 // Step 2. If either side cannot promote at least three plies before the other side then situation
1009 // becomes too complex and we give up. Otherwise we determine the possibly "winning side"
1010 if (abs(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3)
1013 winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK);
1014 loserSide = ~winnerSide;
1016 // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
1017 b = candidates = pos.pieces(loserSide, PAWN);
1023 // Compute plies from queening
1024 queeningSquare = relative_square(loserSide, file_of(s) | RANK_8);
1025 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
1026 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
1028 // Check if (without even considering any obstacles) we're too far away or doubled
1029 if ( pliesToQueen[winnerSide] + 3 <= pliesToGo
1030 || (forward_bb(loserSide, s) & pos.pieces(loserSide, PAWN)))
1034 // If any candidate is already a passed pawn it _may_ promote in time. We give up.
1035 if (candidates & ei.pi->passed_pawns(loserSide))
1038 // Step 4. Check new passed pawn creation through king capturing and pawn sacrifices
1044 sacptg = blockersCount = 0;
1045 minKingDist = kingptg = 256;
1047 // Compute plies from queening
1048 queeningSquare = relative_square(loserSide, file_of(s) | RANK_8);
1049 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
1050 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
1052 // Generate list of blocking pawns and supporters
1053 supporters = adjacent_files_bb(file_of(s)) & candidates;
1054 opposed = forward_bb(loserSide, s) & pos.pieces(winnerSide, PAWN);
1055 blockers = passed_pawn_mask(loserSide, s) & pos.pieces(winnerSide, PAWN);
1059 // How many plies does it take to remove all the blocking pawns?
1062 blockSq = pop_lsb(&blockers);
1065 // Check pawns that can give support to overcome obstacle, for instance
1066 // black pawns: a4, b4 white: b2 then pawn in b4 is giving support.
1069 b2 = supporters & in_front_bb(winnerSide, blockSq + pawn_push(winnerSide));
1071 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1073 d = square_distance(blockSq, pop_lsb(&b2)) - 2;
1074 movesToGo = std::min(movesToGo, d);
1078 // Check pawns that can be sacrificed against the blocking pawn
1079 b2 = attack_span_mask(winnerSide, blockSq) & candidates & ~(1ULL << s);
1081 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1083 d = square_distance(blockSq, pop_lsb(&b2)) - 2;
1084 movesToGo = std::min(movesToGo, d);
1087 // If obstacle can be destroyed with an immediate pawn exchange / sacrifice,
1088 // it's not a real obstacle and we have nothing to add to pliesToGo.
1092 // Plies needed to sacrifice against all the blocking pawns
1093 sacptg += movesToGo * 2;
1096 // Plies needed for the king to capture all the blocking pawns
1097 d = square_distance(pos.king_square(loserSide), blockSq);
1098 minKingDist = std::min(minKingDist, d);
1099 kingptg = (minKingDist + blockersCount) * 2;
1102 // Check if pawn sacrifice plan _may_ save the day
1103 if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg)
1106 // Check if king capture plan _may_ save the day (contains some false positives)
1107 if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg)
1111 // Winning pawn is unstoppable and will promote as first, return big score
1112 Score score = make_score(0, (Value) 1280 - 32 * pliesToQueen[winnerSide]);
1113 return winnerSide == WHITE ? score : -score;
1117 // evaluate_space() computes the space evaluation for a given side. The
1118 // space evaluation is a simple bonus based on the number of safe squares
1119 // available for minor pieces on the central four files on ranks 2--4. Safe
1120 // squares one, two or three squares behind a friendly pawn are counted
1121 // twice. Finally, the space bonus is scaled by a weight taken from the
1122 // material hash table. The aim is to improve play on game opening.
1124 int evaluate_space(const Position& pos, EvalInfo& ei) {
1126 const Color Them = (Us == WHITE ? BLACK : WHITE);
1128 // Find the safe squares for our pieces inside the area defined by
1129 // SpaceMask[]. A square is unsafe if it is attacked by an enemy
1130 // pawn, or if it is undefended and attacked by an enemy piece.
1131 Bitboard safe = SpaceMask[Us]
1132 & ~pos.pieces(Us, PAWN)
1133 & ~ei.attackedBy[Them][PAWN]
1134 & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
1136 // Find all squares which are at most three squares behind some friendly pawn
1137 Bitboard behind = pos.pieces(Us, PAWN);
1138 behind |= (Us == WHITE ? behind >> 8 : behind << 8);
1139 behind |= (Us == WHITE ? behind >> 16 : behind << 16);
1141 // Since SpaceMask[Us] is fully on our half of the board
1142 assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);
1144 // Count safe + (behind & safe) with a single popcount
1145 return popcount<Full>((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
1149 // interpolate() interpolates between a middle game and an endgame score,
1150 // based on game phase. It also scales the return value by a ScaleFactor array.
1152 Value interpolate(const Score& v, Phase ph, ScaleFactor sf) {
1154 assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
1155 assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
1156 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1158 int ev = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
1159 int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128;
1160 return Value((result + GrainSize / 2) & ~(GrainSize - 1));
1164 // weight_option() computes the value of an evaluation weight, by combining
1165 // two UCI-configurable weights (midgame and endgame) with an internal weight.
1167 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
1169 // Scale option value from 100 to 256
1170 int mg = Options[mgOpt] * 256 / 100;
1171 int eg = Options[egOpt] * 256 / 100;
1173 return apply_weight(make_score(mg, eg), internalWeight);
1177 // A couple of little helpers used by tracing code, to_cp() converts a value to
1178 // a double in centipawns scale, trace_add() stores white and black scores.
1180 double to_cp(Value v) { return double(v) / double(PawnValueMg); }
1182 void trace_add(int idx, Score wScore, Score bScore) {
1184 TracedScores[WHITE][idx] = wScore;
1185 TracedScores[BLACK][idx] = bScore;
1189 // trace_row() is an helper function used by tracing code to register the
1190 // values of a single evaluation term.
1192 void trace_row(const char* name, int idx) {
1194 Score wScore = TracedScores[WHITE][idx];
1195 Score bScore = TracedScores[BLACK][idx];
1198 case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL:
1199 TraceStream << std::setw(20) << name << " | --- --- | --- --- | "
1200 << std::setw(6) << to_cp(mg_value(wScore)) << " "
1201 << std::setw(6) << to_cp(eg_value(wScore)) << " \n";
1204 TraceStream << std::setw(20) << name << " | " << std::noshowpos
1205 << std::setw(5) << to_cp(mg_value(wScore)) << " "
1206 << std::setw(5) << to_cp(eg_value(wScore)) << " | "
1207 << std::setw(5) << to_cp(mg_value(bScore)) << " "
1208 << std::setw(5) << to_cp(eg_value(bScore)) << " | "
1210 << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " "
1211 << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n";