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 = 4;
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(-35,-30), S(-22,-20), S(-9,-10), S( 3, 0), S(15, 10), S(27, 20), // Knights
100 S( 37, 28), S( 42, 31), S(44, 33) },
101 { S(-22,-27), S( -8,-13), S( 6, 1), S(20, 15), S(34, 29), S(48, 43), // Bishops
102 S( 60, 55), S( 68, 63), S(74, 68), S(77, 72), S(80, 75), S(82, 77),
103 S( 84, 79), S( 86, 81), S(87, 82), S(87, 82) },
104 { S(-17,-33), S(-11,-16), S(-5, 0), S( 1, 16), S( 7, 32), S(13, 48), // Rooks
105 S( 18, 64), S( 22, 80), S(26, 96), S(29,109), S(31,115), S(33,119),
106 S( 35,122), S( 36,123), S(37,124), S(38,124) },
107 { S(-12,-20), S( -8,-13), S(-5, -7), S(-2, -1), S( 1, 5), S( 4, 11), // Queens
108 S( 7, 17), S( 10, 23), S(13, 29), S(16, 34), S(18, 38), S(20, 40),
109 S( 22, 41), S( 23, 41), S(24, 41), S(25, 41), S(25, 41), S(25, 41),
110 S( 25, 41), S( 25, 41), S(25, 41), S(25, 41), S(25, 41), S(25, 41),
111 S( 25, 41), S( 25, 41), S(25, 41), S(25, 41), S(25, 41), S(25, 41),
112 S( 25, 41), S( 25, 41) }
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 Tempo = make_score(24, 11);
155 const Score BishopPinBonus = make_score(66, 11);
156 const Score RookOn7thBonus = make_score(11, 20);
157 const Score QueenOn7thBonus = make_score( 3, 8);
158 const Score RookOnPawnBonus = make_score(10, 28);
159 const Score QueenOnPawnBonus = make_score( 4, 20);
160 const Score RookOpenFileBonus = make_score(43, 21);
161 const Score RookHalfOpenFileBonus = make_score(19, 10);
162 const Score BishopPawnsPenalty = make_score( 8, 12);
163 const Score UndefendedMinorPenalty = make_score(25, 10);
164 const Score TrappedRookPenalty = make_score(90, 0);
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(50, 50);
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[COLOR_NB][128];
217 // TracedTerms[Color][PieceType || TracedType] contains a breakdown of the
218 // evaluation terms, used when tracing.
219 Score TracedScores[COLOR_NB][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[]);
240 template<Color Us, bool Trace>
241 Score evaluate_threats(const Position& pos, EvalInfo& ei);
244 int evaluate_space(const Position& pos, EvalInfo& ei);
246 template<Color Us, bool Trace>
247 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
249 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
251 Value interpolate(const Score& v, Phase ph, ScaleFactor sf);
252 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
253 double to_cp(Value v);
254 void trace_add(int idx, Score term_w, Score term_b = SCORE_ZERO);
255 void trace_row(const char* name, int idx);
261 /// evaluate() is the main evaluation function. It always computes two
262 /// values, an endgame score and a middle game score, and interpolates
263 /// between them based on the remaining material.
265 Value evaluate(const Position& pos, Value& margin) {
266 return do_evaluate<false>(pos, margin);
270 /// init() computes evaluation weights from the corresponding UCI parameters
271 /// and setup king tables.
275 Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
276 Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
277 Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
278 Weights[KingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
279 Weights[KingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
281 const int MaxSlope = 30;
282 const int Peak = 1280;
284 for (int t = 0, i = 1; i < 100; i++)
286 t = std::min(Peak, std::min(int(0.4 * i * i), t + MaxSlope));
288 KingDangerTable[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]);
289 KingDangerTable[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]);
294 /// trace() is like evaluate() but instead of a value returns a string suitable
295 /// to be print on stdout with the detailed descriptions and values of each
296 /// evaluation term. Used mainly for debugging.
298 std::string trace(const Position& pos) {
303 Search::RootColor = pos.side_to_move();
306 TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
307 memset(TracedScores, 0, 2 * 16 * sizeof(Score));
309 do_evaluate<true>(pos, margin);
311 totals = TraceStream.str();
314 TraceStream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
315 << " | MG EG | MG EG | MG EG \n"
316 << "---------------------+-------------+-------------+---------------\n";
318 trace_row("Material, PST, Tempo", PST);
319 trace_row("Material imbalance", IMBALANCE);
320 trace_row("Pawns", PAWN);
321 trace_row("Knights", KNIGHT);
322 trace_row("Bishops", BISHOP);
323 trace_row("Rooks", ROOK);
324 trace_row("Queens", QUEEN);
325 trace_row("Mobility", MOBILITY);
326 trace_row("King safety", KING);
327 trace_row("Threats", THREAT);
328 trace_row("Passed pawns", PASSED);
329 trace_row("Unstoppable pawns", UNSTOPPABLE);
330 trace_row("Space", SPACE);
332 TraceStream << "---------------------+-------------+-------------+---------------\n";
333 trace_row("Total", TOTAL);
334 TraceStream << totals;
336 return TraceStream.str();
345 Value do_evaluate(const Position& pos, Value& margin) {
347 assert(!pos.checkers());
350 Value margins[COLOR_NB];
351 Score score, mobilityWhite, mobilityBlack;
352 Thread* th = pos.this_thread();
354 // margins[] store the uncertainty estimation of position's evaluation
355 // that typically is used by the search for pruning decisions.
356 margins[WHITE] = margins[BLACK] = VALUE_ZERO;
358 // Initialize score by reading the incrementally updated scores included
359 // in the position object (material + piece square tables) and adding
360 // Tempo bonus. Score is computed from the point of view of white.
361 score = pos.psq_score() + (pos.side_to_move() == WHITE ? Tempo : -Tempo);
363 // Probe the material hash table
364 ei.mi = Material::probe(pos, th->materialTable, th->endgames);
365 score += ei.mi->material_value();
367 // If we have a specialized evaluation function for the current material
368 // configuration, call it and return.
369 if (ei.mi->specialized_eval_exists())
372 return ei.mi->evaluate(pos);
375 // Probe the pawn hash table
376 ei.pi = Pawns::probe(pos, th->pawnsTable);
377 score += ei.pi->pawns_value();
379 // Initialize attack and king safety bitboards
380 init_eval_info<WHITE>(pos, ei);
381 init_eval_info<BLACK>(pos, ei);
383 // Evaluate pieces and mobility
384 score += evaluate_pieces_of_color<WHITE, Trace>(pos, ei, mobilityWhite)
385 - evaluate_pieces_of_color<BLACK, Trace>(pos, ei, mobilityBlack);
387 score += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
389 // Evaluate kings after all other pieces because we need complete attack
390 // information when computing the king safety evaluation.
391 score += evaluate_king<WHITE, Trace>(pos, ei, margins)
392 - evaluate_king<BLACK, Trace>(pos, ei, margins);
394 // Evaluate tactical threats, we need full attack information including king
395 score += evaluate_threats<WHITE, Trace>(pos, ei)
396 - evaluate_threats<BLACK, Trace>(pos, ei);
398 // Evaluate passed pawns, we need full attack information including king
399 score += evaluate_passed_pawns<WHITE, Trace>(pos, ei)
400 - evaluate_passed_pawns<BLACK, Trace>(pos, ei);
402 // If one side has only a king, check whether exists any unstoppable passed pawn
403 if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
404 score += evaluate_unstoppable_pawns(pos, ei);
406 // Evaluate space for both sides, only in middle-game.
407 if (ei.mi->space_weight())
409 int s = evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei);
410 score += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]);
413 // Scale winning side if position is more drawish that what it appears
414 ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE)
415 : ei.mi->scale_factor(pos, BLACK);
417 // If we don't already have an unusual scale factor, check for opposite
418 // colored bishop endgames, and use a lower scale for those.
419 if ( ei.mi->game_phase() < PHASE_MIDGAME
420 && pos.opposite_bishops()
421 && sf == SCALE_FACTOR_NORMAL)
423 // Only the two bishops ?
424 if ( pos.non_pawn_material(WHITE) == BishopValueMg
425 && pos.non_pawn_material(BLACK) == BishopValueMg)
427 // Check for KBP vs KB with only a single pawn that is almost
428 // certainly a draw or at least two pawns.
429 bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
430 sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
433 // Endgame with opposite-colored bishops, but also other pieces. Still
434 // a bit drawish, but not as drawish as with only the two bishops.
435 sf = ScaleFactor(50);
438 margin = margins[pos.side_to_move()];
439 Value v = interpolate(score, ei.mi->game_phase(), sf);
441 // In case of tracing add all single evaluation contributions for both white and black
444 trace_add(PST, pos.psq_score());
445 trace_add(IMBALANCE, ei.mi->material_value());
446 trace_add(PAWN, ei.pi->pawns_value());
447 trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns(pos, ei));
448 Score w = make_score(ei.mi->space_weight() * evaluate_space<WHITE>(pos, ei), 0);
449 Score b = make_score(ei.mi->space_weight() * evaluate_space<BLACK>(pos, ei), 0);
450 trace_add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
451 trace_add(TOTAL, score);
452 TraceStream << "\nUncertainty margin: White: " << to_cp(margins[WHITE])
453 << ", Black: " << to_cp(margins[BLACK])
454 << "\nScaling: " << std::noshowpos
455 << std::setw(6) << 100.0 * ei.mi->game_phase() / 128.0 << "% MG, "
456 << std::setw(6) << 100.0 * (1.0 - ei.mi->game_phase() / 128.0) << "% * "
457 << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
458 << "Total evaluation: " << to_cp(v);
461 return pos.side_to_move() == WHITE ? v : -v;
465 // init_eval_info() initializes king bitboards for given color adding
466 // pawn attacks. To be done at the beginning of the evaluation.
469 void init_eval_info(const Position& pos, EvalInfo& ei) {
471 const Color Them = (Us == WHITE ? BLACK : WHITE);
473 Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
474 ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
476 // Init king safety tables only if we are going to use them
477 if ( pos.piece_count(Us, QUEEN)
478 && pos.non_pawn_material(Us) > QueenValueMg + PawnValueMg)
480 ei.kingRing[Them] = (b | (Us == WHITE ? b >> 8 : b << 8));
481 b &= ei.attackedBy[Us][PAWN];
482 ei.kingAttackersCount[Us] = b ? popcount<Max15>(b) / 2 : 0;
483 ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
485 ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0;
489 // evaluate_outposts() evaluates bishop and knight outposts squares
491 template<PieceType Piece, Color Us>
492 Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
494 const Color Them = (Us == WHITE ? BLACK : WHITE);
496 assert (Piece == BISHOP || Piece == KNIGHT);
498 // Initial bonus based on square
499 Value bonus = OutpostBonus[Piece == BISHOP][relative_square(Us, s)];
501 // Increase bonus if supported by pawn, especially if the opponent has
502 // no minor piece which can exchange the outpost piece.
503 if (bonus && (ei.attackedBy[Us][PAWN] & s))
505 if ( !pos.pieces(Them, KNIGHT)
506 && !(same_color_squares(s) & pos.pieces(Them, BISHOP)))
507 bonus += bonus + bonus / 2;
511 return make_score(bonus, bonus);
515 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
517 template<PieceType Piece, Color Us, bool Trace>
518 Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
522 Score score = SCORE_ZERO;
524 const Color Them = (Us == WHITE ? BLACK : WHITE);
525 const Square* pl = pos.piece_list(Us, Piece);
527 ei.attackedBy[Us][Piece] = 0;
529 while ((s = *pl++) != SQ_NONE)
531 // Find attacked squares, including x-ray attacks for bishops and rooks
532 b = Piece == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(Us, QUEEN))
533 : Piece == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN))
534 : pos.attacks_from<Piece>(s);
536 ei.attackedBy[Us][Piece] |= b;
538 if (b & ei.kingRing[Them])
540 ei.kingAttackersCount[Us]++;
541 ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
542 Bitboard bb = (b & ei.attackedBy[Them][KING]);
544 ei.kingAdjacentZoneAttacksCount[Us] += popcount<Max15>(bb);
547 int mob = popcount<Piece == QUEEN ? Full : Max15>(b & mobilityArea);
548 mobility += MobilityBonus[Piece][mob];
550 // Decrease score if we are attacked by an enemy pawn. Remaining part
551 // of threat evaluation must be done later when we have full attack info.
552 if (ei.attackedBy[Them][PAWN] & s)
553 score -= ThreatenedByPawnPenalty[Piece];
555 // Otherwise give a bonus if we are a bishop and can pin a piece or can
556 // give a discovered check through an x-ray attack.
557 else if ( Piece == BISHOP
558 && (PseudoAttacks[Piece][pos.king_square(Them)] & s)
559 && !more_than_one(BetweenBB[s][pos.king_square(Them)] & pos.pieces()))
560 score += BishopPinBonus;
562 // Penalty for bishop with same coloured pawns
564 score -= BishopPawnsPenalty * ei.pi->pawns_on_same_color_squares(Us, s);
566 // Bishop and knight outposts squares
567 if ( (Piece == BISHOP || Piece == KNIGHT)
568 && !(pos.pieces(Them, PAWN) & attack_span_mask(Us, s)))
569 score += evaluate_outposts<Piece, Us>(pos, ei, s);
571 if ( (Piece == ROOK || Piece == QUEEN)
572 && relative_rank(Us, s) >= RANK_5)
574 // Major piece on 7th rank and enemy king trapped on 8th
575 if ( relative_rank(Us, s) == RANK_7
576 && relative_rank(Us, pos.king_square(Them)) == RANK_8)
577 score += Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus;
579 // Major piece attacking enemy pawns on the same rank
580 Bitboard pawns = pos.pieces(Them, PAWN) & rank_bb(s);
582 score += popcount<Max15>(pawns) * (Piece == ROOK ? RookOnPawnBonus : QueenOnPawnBonus);
585 // Special extra evaluation for rooks
588 // Give a bonus for a rook on a open or half-open file
589 if (ei.pi->half_open(Us, file_of(s)))
590 score += ei.pi->half_open(Them, file_of(s)) ? RookOpenFileBonus
591 : RookHalfOpenFileBonus;
592 if (mob > 6 || ei.pi->half_open(Us, file_of(s)))
595 Square ksq = pos.king_square(Us);
597 // Penalize rooks which are trapped inside a king. Penalize more if
598 // king has lost right to castle.
599 if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
600 && (rank_of(ksq) == rank_of(s) || relative_rank(Us, ksq) == RANK_1)
601 && !ei.pi->half_open_on_side(Us, file_of(ksq), file_of(ksq) < FILE_E))
602 score -= (TrappedRookPenalty - make_score(mob * 8, 0)) * (pos.can_castle(Us) ? 1 : 2);
605 // An important Chess960 pattern: A cornered bishop blocked by a friendly
606 // pawn diagonally in front of it is a very serious problem, especially
607 // when that pawn is also blocked.
610 && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
612 const enum Piece P = make_piece(Us, PAWN);
613 Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
614 if (pos.piece_on(s + d) == P)
615 score -= !pos.is_empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1Penalty * 4
616 : pos.piece_on(s + d + d) == P ? TrappedBishopA1H1Penalty * 2
617 : TrappedBishopA1H1Penalty;
622 TracedScores[Us][Piece] = score;
628 // evaluate_threats<>() assigns bonuses according to the type of attacking piece
629 // and the type of attacked one.
631 template<Color Us, bool Trace>
632 Score evaluate_threats(const Position& pos, EvalInfo& ei) {
634 const Color Them = (Us == WHITE ? BLACK : WHITE);
636 Bitboard b, undefendedMinors, weakEnemies;
637 Score score = SCORE_ZERO;
639 // Undefended minors get penalized even if not under attack
640 undefendedMinors = pos.pieces(Them, BISHOP, KNIGHT)
641 & ~ei.attackedBy[Them][ALL_PIECES];
643 if (undefendedMinors)
644 score += UndefendedMinorPenalty;
646 // Enemy pieces not defended by a pawn and under our attack
647 weakEnemies = pos.pieces(Them)
648 & ~ei.attackedBy[Them][PAWN]
649 & ei.attackedBy[Us][ALL_PIECES];
651 // Add bonus according to type of attacked enemy piece and to the
652 // type of attacking piece, from knights to queens. Kings are not
653 // considered because are already handled in king evaluation.
655 for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
657 b = ei.attackedBy[Us][pt1] & weakEnemies;
659 for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
660 if (b & pos.pieces(pt2))
661 score += ThreatBonus[pt1][pt2];
665 TracedScores[Us][THREAT] = score;
671 // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
672 // pieces of a given color.
674 template<Color Us, bool Trace>
675 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) {
677 const Color Them = (Us == WHITE ? BLACK : WHITE);
679 Score score = mobility = SCORE_ZERO;
681 // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
682 const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces(Us, PAWN, KING));
684 score += evaluate_pieces<KNIGHT, Us, Trace>(pos, ei, mobility, mobilityArea);
685 score += evaluate_pieces<BISHOP, Us, Trace>(pos, ei, mobility, mobilityArea);
686 score += evaluate_pieces<ROOK, Us, Trace>(pos, ei, mobility, mobilityArea);
687 score += evaluate_pieces<QUEEN, Us, Trace>(pos, ei, mobility, mobilityArea);
689 // Sum up all attacked squares
690 ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
691 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
692 | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
694 TracedScores[Us][MOBILITY] = apply_weight(mobility, Weights[Mobility]);
700 // evaluate_king<>() assigns bonuses and penalties to a king of a given color
702 template<Color Us, bool Trace>
703 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
705 const Color Them = (Us == WHITE ? BLACK : WHITE);
707 Bitboard undefended, b, b1, b2, safe;
709 const Square ksq = pos.king_square(Us);
711 // King shelter and enemy pawns storm
712 Score score = ei.pi->king_safety<Us>(pos, ksq);
714 // King safety. This is quite complicated, and is almost certainly far
715 // from optimally tuned.
716 if ( ei.kingAttackersCount[Them] >= 2
717 && ei.kingAdjacentZoneAttacksCount[Them])
719 // Find the attacked squares around the king which has no defenders
720 // apart from the king itself
721 undefended = ei.attackedBy[Them][ALL_PIECES] & ei.attackedBy[Us][KING];
722 undefended &= ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
723 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
724 | ei.attackedBy[Us][QUEEN]);
726 // Initialize the 'attackUnits' variable, which is used later on as an
727 // index to the KingDangerTable[] array. The initial value is based on
728 // the number and types of the enemy's attacking pieces, the number of
729 // attacked and undefended squares around our king, the square of the
730 // king, and the quality of the pawn shelter.
731 attackUnits = std::min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
732 + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount<Max15>(undefended))
733 + InitKingDanger[relative_square(Us, ksq)]
734 - mg_value(score) / 32;
736 // Analyse enemy's safe queen contact checks. First find undefended
737 // squares around the king attacked by enemy queen...
738 b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
741 // ...then remove squares not supported by another enemy piece
742 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
743 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
745 attackUnits += QueenContactCheckBonus
747 * (Them == pos.side_to_move() ? 2 : 1);
750 // Analyse enemy's safe rook contact checks. First find undefended
751 // squares around the king attacked by enemy rooks...
752 b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
754 // Consider only squares where the enemy rook gives check
755 b &= PseudoAttacks[ROOK][ksq];
759 // ...then remove squares not supported by another enemy piece
760 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
761 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]);
763 attackUnits += RookContactCheckBonus
765 * (Them == pos.side_to_move() ? 2 : 1);
768 // Analyse enemy's safe distance checks for sliders and knights
769 safe = ~(pos.pieces(Them) | ei.attackedBy[Us][ALL_PIECES]);
771 b1 = pos.attacks_from<ROOK>(ksq) & safe;
772 b2 = pos.attacks_from<BISHOP>(ksq) & safe;
774 // Enemy queen safe checks
775 b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
777 attackUnits += QueenCheckBonus * popcount<Max15>(b);
779 // Enemy rooks safe checks
780 b = b1 & ei.attackedBy[Them][ROOK];
782 attackUnits += RookCheckBonus * popcount<Max15>(b);
784 // Enemy bishops safe checks
785 b = b2 & ei.attackedBy[Them][BISHOP];
787 attackUnits += BishopCheckBonus * popcount<Max15>(b);
789 // Enemy knights safe checks
790 b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
792 attackUnits += KnightCheckBonus * popcount<Max15>(b);
794 // To index KingDangerTable[] attackUnits must be in [0, 99] range
795 attackUnits = std::min(99, std::max(0, attackUnits));
797 // Finally, extract the king danger score from the KingDangerTable[]
798 // array and subtract the score from evaluation. Set also margins[]
799 // value that will be used for pruning because this value can sometimes
800 // be very big, and so capturing a single attacking piece can therefore
801 // result in a score change far bigger than the value of the captured piece.
802 score -= KingDangerTable[Us == Search::RootColor][attackUnits];
803 margins[Us] += mg_value(KingDangerTable[Us == Search::RootColor][attackUnits]);
807 TracedScores[Us][KING] = score;
813 // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
815 template<Color Us, bool Trace>
816 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
818 const Color Them = (Us == WHITE ? BLACK : WHITE);
820 Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
821 Score score = SCORE_ZERO;
823 b = ei.pi->passed_pawns(Us);
827 Square s = pop_lsb(&b);
829 assert(pos.pawn_is_passed(Us, s));
831 int r = int(relative_rank(Us, s) - RANK_2);
832 int rr = r * (r - 1);
834 // Base bonus based on rank
835 Value mbonus = Value(20 * rr);
836 Value ebonus = Value(10 * (rr + r + 1));
840 Square blockSq = s + pawn_push(Us);
842 // Adjust bonus based on kings proximity
843 ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 5 * rr);
844 ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 2 * rr);
846 // If blockSq is not the queening square then consider also a second push
847 if (rank_of(blockSq) != (Us == WHITE ? RANK_8 : RANK_1))
848 ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
850 // If the pawn is free to advance, increase bonus
851 if (pos.is_empty(blockSq))
853 squaresToQueen = forward_bb(Us, s);
854 defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES];
856 // If there is an enemy rook or queen attacking the pawn from behind,
857 // add all X-ray attacks by the rook or queen. Otherwise consider only
858 // the squares in the pawn's path attacked or occupied by the enemy.
859 if ( (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN))
860 && (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN) & pos.attacks_from<ROOK>(s)))
861 unsafeSquares = squaresToQueen;
863 unsafeSquares = squaresToQueen & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
865 // If there aren't enemy attacks huge bonus, a bit smaller if at
866 // least block square is not attacked, otherwise smallest bonus.
867 int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 3;
869 // Big bonus if the path to queen is fully defended, a bit less
870 // if at least block square is defended.
871 if (defendedSquares == squaresToQueen)
874 else if (defendedSquares & blockSq)
875 k += (unsafeSquares & defendedSquares) == unsafeSquares ? 4 : 2;
877 mbonus += Value(k * rr), ebonus += Value(k * rr);
881 // Increase the bonus if the passed pawn is supported by a friendly pawn
882 // on the same rank and a bit smaller if it's on the previous rank.
883 supportingPawns = pos.pieces(Us, PAWN) & adjacent_files_bb(file_of(s));
884 if (supportingPawns & rank_bb(s))
885 ebonus += Value(r * 20);
887 else if (supportingPawns & rank_bb(s - pawn_push(Us)))
888 ebonus += Value(r * 12);
890 // Rook pawns are a special case: They are sometimes worse, and
891 // sometimes better than other passed pawns. It is difficult to find
892 // good rules for determining whether they are good or bad. For now,
893 // we try the following: Increase the value for rook pawns if the
894 // other side has no pieces apart from a knight, and decrease the
895 // value if the other side has a rook or queen.
896 if (file_of(s) == FILE_A || file_of(s) == FILE_H)
898 if (pos.non_pawn_material(Them) <= KnightValueMg)
899 ebonus += ebonus / 4;
900 else if (pos.pieces(Them, ROOK, QUEEN))
901 ebonus -= ebonus / 4;
903 score += make_score(mbonus, ebonus);
908 TracedScores[Us][PASSED] = apply_weight(score, Weights[PassedPawns]);
910 // Add the scores to the middle game and endgame eval
911 return apply_weight(score, Weights[PassedPawns]);
915 // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides, this is quite
916 // conservative and returns a winning score only when we are very sure that the pawn is winning.
918 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
920 Bitboard b, b2, blockers, supporters, queeningPath, candidates;
921 Square s, blockSq, queeningSquare;
922 Color c, winnerSide, loserSide;
923 bool pathDefended, opposed;
924 int pliesToGo, movesToGo, oppMovesToGo, sacptg, blockersCount, minKingDist, kingptg, d;
925 int pliesToQueen[] = { 256, 256 };
927 // Step 1. Hunt for unstoppable passed pawns. If we find at least one,
928 // record how many plies are required for promotion.
929 for (c = WHITE; c <= BLACK; c++)
931 // Skip if other side has non-pawn pieces
932 if (pos.non_pawn_material(~c))
935 b = ei.pi->passed_pawns(c);
940 queeningSquare = relative_square(c, file_of(s) | RANK_8);
941 queeningPath = forward_bb(c, s);
943 // Compute plies to queening and check direct advancement
944 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(c, s) == RANK_2);
945 oppMovesToGo = square_distance(pos.king_square(~c), queeningSquare) - int(c != pos.side_to_move());
946 pathDefended = ((ei.attackedBy[c][ALL_PIECES] & queeningPath) == queeningPath);
948 if (movesToGo >= oppMovesToGo && !pathDefended)
951 // Opponent king cannot block because path is defended and position
952 // is not in check. So only friendly pieces can be blockers.
953 assert(!pos.checkers());
954 assert((queeningPath & pos.pieces()) == (queeningPath & pos.pieces(c)));
956 // Add moves needed to free the path from friendly pieces and retest condition
957 movesToGo += popcount<Max15>(queeningPath & pos.pieces(c));
959 if (movesToGo >= oppMovesToGo && !pathDefended)
962 pliesToGo = 2 * movesToGo - int(c == pos.side_to_move());
963 pliesToQueen[c] = std::min(pliesToQueen[c], pliesToGo);
967 // Step 2. If either side cannot promote at least three plies before the other side then situation
968 // becomes too complex and we give up. Otherwise we determine the possibly "winning side"
969 if (abs(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3)
972 winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK);
973 loserSide = ~winnerSide;
975 // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
976 b = candidates = pos.pieces(loserSide, PAWN);
982 // Compute plies from queening
983 queeningSquare = relative_square(loserSide, file_of(s) | RANK_8);
984 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
985 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
987 // Check if (without even considering any obstacles) we're too far away or doubled
988 if ( pliesToQueen[winnerSide] + 3 <= pliesToGo
989 || (forward_bb(loserSide, s) & pos.pieces(loserSide, PAWN)))
993 // If any candidate is already a passed pawn it _may_ promote in time. We give up.
994 if (candidates & ei.pi->passed_pawns(loserSide))
997 // Step 4. Check new passed pawn creation through king capturing and pawn sacrifices
1003 sacptg = blockersCount = 0;
1004 minKingDist = kingptg = 256;
1006 // Compute plies from queening
1007 queeningSquare = relative_square(loserSide, file_of(s) | RANK_8);
1008 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
1009 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
1011 // Generate list of blocking pawns and supporters
1012 supporters = adjacent_files_bb(file_of(s)) & candidates;
1013 opposed = forward_bb(loserSide, s) & pos.pieces(winnerSide, PAWN);
1014 blockers = passed_pawn_mask(loserSide, s) & pos.pieces(winnerSide, PAWN);
1018 // How many plies does it take to remove all the blocking pawns?
1021 blockSq = pop_lsb(&blockers);
1024 // Check pawns that can give support to overcome obstacle, for instance
1025 // black pawns: a4, b4 white: b2 then pawn in b4 is giving support.
1028 b2 = supporters & in_front_bb(winnerSide, blockSq + pawn_push(winnerSide));
1030 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1032 d = square_distance(blockSq, pop_lsb(&b2)) - 2;
1033 movesToGo = std::min(movesToGo, d);
1037 // Check pawns that can be sacrificed against the blocking pawn
1038 b2 = attack_span_mask(winnerSide, blockSq) & candidates & ~(1ULL << s);
1040 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1042 d = square_distance(blockSq, pop_lsb(&b2)) - 2;
1043 movesToGo = std::min(movesToGo, d);
1046 // If obstacle can be destroyed with an immediate pawn exchange / sacrifice,
1047 // it's not a real obstacle and we have nothing to add to pliesToGo.
1051 // Plies needed to sacrifice against all the blocking pawns
1052 sacptg += movesToGo * 2;
1055 // Plies needed for the king to capture all the blocking pawns
1056 d = square_distance(pos.king_square(loserSide), blockSq);
1057 minKingDist = std::min(minKingDist, d);
1058 kingptg = (minKingDist + blockersCount) * 2;
1061 // Check if pawn sacrifice plan _may_ save the day
1062 if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg)
1065 // Check if king capture plan _may_ save the day (contains some false positives)
1066 if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg)
1070 // Winning pawn is unstoppable and will promote as first, return big score
1071 Score score = make_score(0, (Value) 1280 - 32 * pliesToQueen[winnerSide]);
1072 return winnerSide == WHITE ? score : -score;
1076 // evaluate_space() computes the space evaluation for a given side. The
1077 // space evaluation is a simple bonus based on the number of safe squares
1078 // available for minor pieces on the central four files on ranks 2--4. Safe
1079 // squares one, two or three squares behind a friendly pawn are counted
1080 // twice. Finally, the space bonus is scaled by a weight taken from the
1081 // material hash table. The aim is to improve play on game opening.
1083 int evaluate_space(const Position& pos, EvalInfo& ei) {
1085 const Color Them = (Us == WHITE ? BLACK : WHITE);
1087 // Find the safe squares for our pieces inside the area defined by
1088 // SpaceMask[]. A square is unsafe if it is attacked by an enemy
1089 // pawn, or if it is undefended and attacked by an enemy piece.
1090 Bitboard safe = SpaceMask[Us]
1091 & ~pos.pieces(Us, PAWN)
1092 & ~ei.attackedBy[Them][PAWN]
1093 & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
1095 // Find all squares which are at most three squares behind some friendly pawn
1096 Bitboard behind = pos.pieces(Us, PAWN);
1097 behind |= (Us == WHITE ? behind >> 8 : behind << 8);
1098 behind |= (Us == WHITE ? behind >> 16 : behind << 16);
1100 // Since SpaceMask[Us] is fully on our half of the board
1101 assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);
1103 // Count safe + (behind & safe) with a single popcount
1104 return popcount<Full>((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
1108 // interpolate() interpolates between a middle game and an endgame score,
1109 // based on game phase. It also scales the return value by a ScaleFactor array.
1111 Value interpolate(const Score& v, Phase ph, ScaleFactor sf) {
1113 assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
1114 assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
1115 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1117 int ev = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
1118 int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128;
1119 return Value((result + GrainSize / 2) & ~(GrainSize - 1));
1123 // weight_option() computes the value of an evaluation weight, by combining
1124 // two UCI-configurable weights (midgame and endgame) with an internal weight.
1126 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
1128 // Scale option value from 100 to 256
1129 int mg = Options[mgOpt] * 256 / 100;
1130 int eg = Options[egOpt] * 256 / 100;
1132 return apply_weight(make_score(mg, eg), internalWeight);
1136 // A couple of little helpers used by tracing code, to_cp() converts a value to
1137 // a double in centipawns scale, trace_add() stores white and black scores.
1139 double to_cp(Value v) { return double(v) / double(PawnValueMg); }
1141 void trace_add(int idx, Score wScore, Score bScore) {
1143 TracedScores[WHITE][idx] = wScore;
1144 TracedScores[BLACK][idx] = bScore;
1148 // trace_row() is an helper function used by tracing code to register the
1149 // values of a single evaluation term.
1151 void trace_row(const char* name, int idx) {
1153 Score wScore = TracedScores[WHITE][idx];
1154 Score bScore = TracedScores[BLACK][idx];
1157 case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL:
1158 TraceStream << std::setw(20) << name << " | --- --- | --- --- | "
1159 << std::setw(6) << to_cp(mg_value(wScore)) << " "
1160 << std::setw(6) << to_cp(eg_value(wScore)) << " \n";
1163 TraceStream << std::setw(20) << name << " | " << std::noshowpos
1164 << std::setw(5) << to_cp(mg_value(wScore)) << " "
1165 << std::setw(5) << to_cp(eg_value(wScore)) << " | "
1166 << std::setw(5) << to_cp(mg_value(bScore)) << " "
1167 << std::setw(5) << to_cp(eg_value(bScore)) << " | "
1169 << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " "
1170 << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n";