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[]);
241 Score evaluate_threats(const Position& pos, EvalInfo& ei);
244 int evaluate_space(const Position& pos, EvalInfo& ei);
247 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
249 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
251 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>(pos, ei)
396 - evaluate_threats<BLACK>(pos, ei);
398 // Evaluate passed pawns, we need full attack information including king
399 score += evaluate_passed_pawns<WHITE>(pos, ei)
400 - evaluate_passed_pawns<BLACK>(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(MOBILITY, apply_weight(mobilityWhite, Weights[Mobility]), apply_weight(mobilityBlack, Weights[Mobility]));
448 trace_add(THREAT, evaluate_threats<WHITE>(pos, ei), evaluate_threats<BLACK>(pos, ei));
449 trace_add(PASSED, evaluate_passed_pawns<WHITE>(pos, ei), evaluate_passed_pawns<BLACK>(pos, ei));
450 trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns(pos, ei));
451 Score w = make_score(ei.mi->space_weight() * evaluate_space<WHITE>(pos, ei), 0);
452 Score b = make_score(ei.mi->space_weight() * evaluate_space<BLACK>(pos, ei), 0);
453 trace_add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
454 trace_add(TOTAL, score);
455 TraceStream << "\nUncertainty margin: White: " << to_cp(margins[WHITE])
456 << ", Black: " << to_cp(margins[BLACK])
457 << "\nScaling: " << std::noshowpos
458 << std::setw(6) << 100.0 * ei.mi->game_phase() / 128.0 << "% MG, "
459 << std::setw(6) << 100.0 * (1.0 - ei.mi->game_phase() / 128.0) << "% * "
460 << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
461 << "Total evaluation: " << to_cp(v);
464 return pos.side_to_move() == WHITE ? v : -v;
468 // init_eval_info() initializes king bitboards for given color adding
469 // pawn attacks. To be done at the beginning of the evaluation.
472 void init_eval_info(const Position& pos, EvalInfo& ei) {
474 const Color Them = (Us == WHITE ? BLACK : WHITE);
476 Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
477 ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
479 // Init king safety tables only if we are going to use them
480 if ( pos.piece_count(Us, QUEEN)
481 && pos.non_pawn_material(Us) > QueenValueMg + PawnValueMg)
483 ei.kingRing[Them] = (b | (Us == WHITE ? b >> 8 : b << 8));
484 b &= ei.attackedBy[Us][PAWN];
485 ei.kingAttackersCount[Us] = b ? popcount<Max15>(b) / 2 : 0;
486 ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
488 ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0;
492 // evaluate_outposts() evaluates bishop and knight outposts squares
494 template<PieceType Piece, Color Us>
495 Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
497 const Color Them = (Us == WHITE ? BLACK : WHITE);
499 assert (Piece == BISHOP || Piece == KNIGHT);
501 // Initial bonus based on square
502 Value bonus = OutpostBonus[Piece == BISHOP][relative_square(Us, s)];
504 // Increase bonus if supported by pawn, especially if the opponent has
505 // no minor piece which can exchange the outpost piece.
506 if (bonus && (ei.attackedBy[Us][PAWN] & s))
508 if ( !pos.pieces(Them, KNIGHT)
509 && !(same_color_squares(s) & pos.pieces(Them, BISHOP)))
510 bonus += bonus + bonus / 2;
514 return make_score(bonus, bonus);
518 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
520 template<PieceType Piece, Color Us, bool Trace>
521 Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
525 Score score = SCORE_ZERO;
527 const Color Them = (Us == WHITE ? BLACK : WHITE);
528 const Square* pl = pos.piece_list(Us, Piece);
530 ei.attackedBy[Us][Piece] = 0;
532 while ((s = *pl++) != SQ_NONE)
534 // Find attacked squares, including x-ray attacks for bishops and rooks
535 b = Piece == BISHOP ? attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(Us, QUEEN))
536 : Piece == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN))
537 : pos.attacks_from<Piece>(s);
539 ei.attackedBy[Us][Piece] |= b;
541 if (b & ei.kingRing[Them])
543 ei.kingAttackersCount[Us]++;
544 ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
545 Bitboard bb = (b & ei.attackedBy[Them][KING]);
547 ei.kingAdjacentZoneAttacksCount[Us] += popcount<Max15>(bb);
550 int mob = popcount<Piece == QUEEN ? Full : Max15>(b & mobilityArea);
551 mobility += MobilityBonus[Piece][mob];
553 // Decrease score if we are attacked by an enemy pawn. Remaining part
554 // of threat evaluation must be done later when we have full attack info.
555 if (ei.attackedBy[Them][PAWN] & s)
556 score -= ThreatenedByPawnPenalty[Piece];
558 // Otherwise give a bonus if we are a bishop and can pin a piece or can
559 // give a discovered check through an x-ray attack.
560 else if ( Piece == BISHOP
561 && (PseudoAttacks[Piece][pos.king_square(Them)] & s)
562 && !more_than_one(BetweenBB[s][pos.king_square(Them)] & pos.pieces()))
563 score += BishopPinBonus;
565 // Penalty for bishop with same coloured pawns
567 score -= BishopPawnsPenalty * ei.pi->pawns_on_same_color_squares(Us, s);
569 // Bishop and knight outposts squares
570 if ( (Piece == BISHOP || Piece == KNIGHT)
571 && !(pos.pieces(Them, PAWN) & attack_span_mask(Us, s)))
572 score += evaluate_outposts<Piece, Us>(pos, ei, s);
574 if ( (Piece == ROOK || Piece == QUEEN)
575 && relative_rank(Us, s) >= RANK_5)
577 // Major piece on 7th rank and enemy king trapped on 8th
578 if ( relative_rank(Us, s) == RANK_7
579 && relative_rank(Us, pos.king_square(Them)) == RANK_8)
580 score += Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus;
582 // Major piece attacking enemy pawns on the same rank
583 Bitboard pawns = pos.pieces(Them, PAWN) & rank_bb(s);
585 score += popcount<Max15>(pawns) * (Piece == ROOK ? RookOnPawnBonus : QueenOnPawnBonus);
588 // Special extra evaluation for rooks
591 // Give a bonus for a rook on a open or half-open file
592 if (ei.pi->half_open(Us, file_of(s)))
593 score += ei.pi->half_open(Them, file_of(s)) ? RookOpenFileBonus
594 : RookHalfOpenFileBonus;
595 if (mob > 6 || ei.pi->half_open(Us, file_of(s)))
598 Square ksq = pos.king_square(Us);
600 // Penalize rooks which are trapped inside a king. Penalize more if
601 // king has lost right to castle.
602 if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
603 && (rank_of(ksq) == rank_of(s) || relative_rank(Us, ksq) == RANK_1)
604 && !ei.pi->half_open_on_side(Us, file_of(ksq), file_of(ksq) < FILE_E))
605 score -= (TrappedRookPenalty - make_score(mob * 8, 0)) * (pos.can_castle(Us) ? 1 : 2);
608 // An important Chess960 pattern: A cornered bishop blocked by a friendly
609 // pawn diagonally in front of it is a very serious problem, especially
610 // when that pawn is also blocked.
613 && (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1)))
615 const enum Piece P = make_piece(Us, PAWN);
616 Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
617 if (pos.piece_on(s + d) == P)
618 score -= !pos.is_empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1Penalty * 4
619 : pos.piece_on(s + d + d) == P ? TrappedBishopA1H1Penalty * 2
620 : TrappedBishopA1H1Penalty;
625 TracedScores[Us][Piece] = score;
631 // evaluate_threats<>() assigns bonuses according to the type of attacking piece
632 // and the type of attacked one.
635 Score evaluate_threats(const Position& pos, EvalInfo& ei) {
637 const Color Them = (Us == WHITE ? BLACK : WHITE);
639 Bitboard b, undefendedMinors, weakEnemies;
640 Score score = SCORE_ZERO;
642 // Undefended minors get penalized even if not under attack
643 undefendedMinors = pos.pieces(Them, BISHOP, KNIGHT)
644 & ~ei.attackedBy[Them][ALL_PIECES];
646 if (undefendedMinors)
647 score += UndefendedMinorPenalty;
649 // Enemy pieces not defended by a pawn and under our attack
650 weakEnemies = pos.pieces(Them)
651 & ~ei.attackedBy[Them][PAWN]
652 & ei.attackedBy[Us][ALL_PIECES];
657 // Add bonus according to type of attacked enemy piece and to the
658 // type of attacking piece, from knights to queens. Kings are not
659 // considered because are already handled in king evaluation.
660 for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
662 b = ei.attackedBy[Us][pt1] & weakEnemies;
664 for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
665 if (b & pos.pieces(pt2))
666 score += ThreatBonus[pt1][pt2];
672 // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
673 // pieces of a given color.
675 template<Color Us, bool Trace>
676 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) {
678 const Color Them = (Us == WHITE ? BLACK : WHITE);
680 Score score = mobility = SCORE_ZERO;
682 // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
683 const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces(Us, PAWN, KING));
685 score += evaluate_pieces<KNIGHT, Us, Trace>(pos, ei, mobility, mobilityArea);
686 score += evaluate_pieces<BISHOP, Us, Trace>(pos, ei, mobility, mobilityArea);
687 score += evaluate_pieces<ROOK, Us, Trace>(pos, ei, mobility, mobilityArea);
688 score += evaluate_pieces<QUEEN, Us, Trace>(pos, ei, mobility, mobilityArea);
690 // Sum up all attacked squares
691 ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
692 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
693 | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
698 // evaluate_king<>() assigns bonuses and penalties to a king of a given color
700 template<Color Us, bool Trace>
701 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
703 const Color Them = (Us == WHITE ? BLACK : WHITE);
705 Bitboard undefended, b, b1, b2, safe;
707 const Square ksq = pos.king_square(Us);
709 // King shelter and enemy pawns storm
710 Score score = ei.pi->king_safety<Us>(pos, ksq);
712 // King safety. This is quite complicated, and is almost certainly far
713 // from optimally tuned.
714 if ( ei.kingAttackersCount[Them] >= 2
715 && ei.kingAdjacentZoneAttacksCount[Them])
717 // Find the attacked squares around the king which has no defenders
718 // apart from the king itself
719 undefended = ei.attackedBy[Them][ALL_PIECES] & ei.attackedBy[Us][KING];
720 undefended &= ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
721 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
722 | ei.attackedBy[Us][QUEEN]);
724 // Initialize the 'attackUnits' variable, which is used later on as an
725 // index to the KingDangerTable[] array. The initial value is based on
726 // the number and types of the enemy's attacking pieces, the number of
727 // attacked and undefended squares around our king, the square of the
728 // king, and the quality of the pawn shelter.
729 attackUnits = std::min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
730 + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount<Max15>(undefended))
731 + InitKingDanger[relative_square(Us, ksq)]
732 - mg_value(score) / 32;
734 // Analyse enemy's safe queen contact checks. First find undefended
735 // squares around the king attacked by enemy queen...
736 b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
739 // ...then remove squares not supported by another enemy piece
740 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
741 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
743 attackUnits += QueenContactCheckBonus
745 * (Them == pos.side_to_move() ? 2 : 1);
748 // Analyse enemy's safe rook contact checks. First find undefended
749 // squares around the king attacked by enemy rooks...
750 b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
752 // Consider only squares where the enemy rook gives check
753 b &= PseudoAttacks[ROOK][ksq];
757 // ...then remove squares not supported by another enemy piece
758 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
759 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]);
761 attackUnits += RookContactCheckBonus
763 * (Them == pos.side_to_move() ? 2 : 1);
766 // Analyse enemy's safe distance checks for sliders and knights
767 safe = ~(pos.pieces(Them) | ei.attackedBy[Us][ALL_PIECES]);
769 b1 = pos.attacks_from<ROOK>(ksq) & safe;
770 b2 = pos.attacks_from<BISHOP>(ksq) & safe;
772 // Enemy queen safe checks
773 b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
775 attackUnits += QueenCheckBonus * popcount<Max15>(b);
777 // Enemy rooks safe checks
778 b = b1 & ei.attackedBy[Them][ROOK];
780 attackUnits += RookCheckBonus * popcount<Max15>(b);
782 // Enemy bishops safe checks
783 b = b2 & ei.attackedBy[Them][BISHOP];
785 attackUnits += BishopCheckBonus * popcount<Max15>(b);
787 // Enemy knights safe checks
788 b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
790 attackUnits += KnightCheckBonus * popcount<Max15>(b);
792 // To index KingDangerTable[] attackUnits must be in [0, 99] range
793 attackUnits = std::min(99, std::max(0, attackUnits));
795 // Finally, extract the king danger score from the KingDangerTable[]
796 // array and subtract the score from evaluation. Set also margins[]
797 // value that will be used for pruning because this value can sometimes
798 // be very big, and so capturing a single attacking piece can therefore
799 // result in a score change far bigger than the value of the captured piece.
800 score -= KingDangerTable[Us == Search::RootColor][attackUnits];
801 margins[Us] += mg_value(KingDangerTable[Us == Search::RootColor][attackUnits]);
805 TracedScores[Us][KING] = score;
811 // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
814 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
816 const Color Them = (Us == WHITE ? BLACK : WHITE);
818 Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
819 Score score = SCORE_ZERO;
821 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);
907 // Add the scores to the middle game and endgame eval
908 return apply_weight(score, Weights[PassedPawns]);
912 // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides, this is quite
913 // conservative and returns a winning score only when we are very sure that the pawn is winning.
915 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
917 Bitboard b, b2, blockers, supporters, queeningPath, candidates;
918 Square s, blockSq, queeningSquare;
919 Color c, winnerSide, loserSide;
920 bool pathDefended, opposed;
921 int pliesToGo, movesToGo, oppMovesToGo, sacptg, blockersCount, minKingDist, kingptg, d;
922 int pliesToQueen[] = { 256, 256 };
924 // Step 1. Hunt for unstoppable passed pawns. If we find at least one,
925 // record how many plies are required for promotion.
926 for (c = WHITE; c <= BLACK; c++)
928 // Skip if other side has non-pawn pieces
929 if (pos.non_pawn_material(~c))
932 b = ei.pi->passed_pawns(c);
937 queeningSquare = relative_square(c, file_of(s) | RANK_8);
938 queeningPath = forward_bb(c, s);
940 // Compute plies to queening and check direct advancement
941 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(c, s) == RANK_2);
942 oppMovesToGo = square_distance(pos.king_square(~c), queeningSquare) - int(c != pos.side_to_move());
943 pathDefended = ((ei.attackedBy[c][ALL_PIECES] & queeningPath) == queeningPath);
945 if (movesToGo >= oppMovesToGo && !pathDefended)
948 // Opponent king cannot block because path is defended and position
949 // is not in check. So only friendly pieces can be blockers.
950 assert(!pos.checkers());
951 assert((queeningPath & pos.pieces()) == (queeningPath & pos.pieces(c)));
953 // Add moves needed to free the path from friendly pieces and retest condition
954 movesToGo += popcount<Max15>(queeningPath & pos.pieces(c));
956 if (movesToGo >= oppMovesToGo && !pathDefended)
959 pliesToGo = 2 * movesToGo - int(c == pos.side_to_move());
960 pliesToQueen[c] = std::min(pliesToQueen[c], pliesToGo);
964 // Step 2. If either side cannot promote at least three plies before the other side then situation
965 // becomes too complex and we give up. Otherwise we determine the possibly "winning side"
966 if (abs(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3)
969 winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK);
970 loserSide = ~winnerSide;
972 // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
973 b = candidates = pos.pieces(loserSide, PAWN);
979 // Compute plies from queening
980 queeningSquare = relative_square(loserSide, file_of(s) | RANK_8);
981 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
982 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
984 // Check if (without even considering any obstacles) we're too far away or doubled
985 if ( pliesToQueen[winnerSide] + 3 <= pliesToGo
986 || (forward_bb(loserSide, s) & pos.pieces(loserSide, PAWN)))
990 // If any candidate is already a passed pawn it _may_ promote in time. We give up.
991 if (candidates & ei.pi->passed_pawns(loserSide))
994 // Step 4. Check new passed pawn creation through king capturing and pawn sacrifices
1000 sacptg = blockersCount = 0;
1001 minKingDist = kingptg = 256;
1003 // Compute plies from queening
1004 queeningSquare = relative_square(loserSide, file_of(s) | RANK_8);
1005 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
1006 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
1008 // Generate list of blocking pawns and supporters
1009 supporters = adjacent_files_bb(file_of(s)) & candidates;
1010 opposed = forward_bb(loserSide, s) & pos.pieces(winnerSide, PAWN);
1011 blockers = passed_pawn_mask(loserSide, s) & pos.pieces(winnerSide, PAWN);
1015 // How many plies does it take to remove all the blocking pawns?
1018 blockSq = pop_lsb(&blockers);
1021 // Check pawns that can give support to overcome obstacle, for instance
1022 // black pawns: a4, b4 white: b2 then pawn in b4 is giving support.
1025 b2 = supporters & in_front_bb(winnerSide, blockSq + pawn_push(winnerSide));
1027 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1029 d = square_distance(blockSq, pop_lsb(&b2)) - 2;
1030 movesToGo = std::min(movesToGo, d);
1034 // Check pawns that can be sacrificed against the blocking pawn
1035 b2 = attack_span_mask(winnerSide, blockSq) & candidates & ~(1ULL << s);
1037 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1039 d = square_distance(blockSq, pop_lsb(&b2)) - 2;
1040 movesToGo = std::min(movesToGo, d);
1043 // If obstacle can be destroyed with an immediate pawn exchange / sacrifice,
1044 // it's not a real obstacle and we have nothing to add to pliesToGo.
1048 // Plies needed to sacrifice against all the blocking pawns
1049 sacptg += movesToGo * 2;
1052 // Plies needed for the king to capture all the blocking pawns
1053 d = square_distance(pos.king_square(loserSide), blockSq);
1054 minKingDist = std::min(minKingDist, d);
1055 kingptg = (minKingDist + blockersCount) * 2;
1058 // Check if pawn sacrifice plan _may_ save the day
1059 if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg)
1062 // Check if king capture plan _may_ save the day (contains some false positives)
1063 if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg)
1067 // Winning pawn is unstoppable and will promote as first, return big score
1068 Score score = make_score(0, (Value) 1280 - 32 * pliesToQueen[winnerSide]);
1069 return winnerSide == WHITE ? score : -score;
1073 // evaluate_space() computes the space evaluation for a given side. The
1074 // space evaluation is a simple bonus based on the number of safe squares
1075 // available for minor pieces on the central four files on ranks 2--4. Safe
1076 // squares one, two or three squares behind a friendly pawn are counted
1077 // twice. Finally, the space bonus is scaled by a weight taken from the
1078 // material hash table. The aim is to improve play on game opening.
1080 int evaluate_space(const Position& pos, EvalInfo& ei) {
1082 const Color Them = (Us == WHITE ? BLACK : WHITE);
1084 // Find the safe squares for our pieces inside the area defined by
1085 // SpaceMask[]. A square is unsafe if it is attacked by an enemy
1086 // pawn, or if it is undefended and attacked by an enemy piece.
1087 Bitboard safe = SpaceMask[Us]
1088 & ~pos.pieces(Us, PAWN)
1089 & ~ei.attackedBy[Them][PAWN]
1090 & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
1092 // Find all squares which are at most three squares behind some friendly pawn
1093 Bitboard behind = pos.pieces(Us, PAWN);
1094 behind |= (Us == WHITE ? behind >> 8 : behind << 8);
1095 behind |= (Us == WHITE ? behind >> 16 : behind << 16);
1097 // Since SpaceMask[Us] is fully on our half of the board
1098 assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);
1100 // Count safe + (behind & safe) with a single popcount
1101 return popcount<Full>((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
1105 // interpolate() interpolates between a middle game and an endgame score,
1106 // based on game phase. It also scales the return value by a ScaleFactor array.
1108 Value interpolate(const Score& v, Phase ph, ScaleFactor sf) {
1110 assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
1111 assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
1112 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1114 int ev = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
1115 int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128;
1116 return Value((result + GrainSize / 2) & ~(GrainSize - 1));
1120 // weight_option() computes the value of an evaluation weight, by combining
1121 // two UCI-configurable weights (midgame and endgame) with an internal weight.
1123 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
1125 // Scale option value from 100 to 256
1126 int mg = Options[mgOpt] * 256 / 100;
1127 int eg = Options[egOpt] * 256 / 100;
1129 return apply_weight(make_score(mg, eg), internalWeight);
1133 // A couple of little helpers used by tracing code, to_cp() converts a value to
1134 // a double in centipawns scale, trace_add() stores white and black scores.
1136 double to_cp(Value v) { return double(v) / double(PawnValueMg); }
1138 void trace_add(int idx, Score wScore, Score bScore) {
1140 TracedScores[WHITE][idx] = wScore;
1141 TracedScores[BLACK][idx] = bScore;
1145 // trace_row() is an helper function used by tracing code to register the
1146 // values of a single evaluation term.
1148 void trace_row(const char* name, int idx) {
1150 Score wScore = TracedScores[WHITE][idx];
1151 Score bScore = TracedScores[BLACK][idx];
1154 case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL:
1155 TraceStream << std::setw(20) << name << " | --- --- | --- --- | "
1156 << std::setw(6) << to_cp(mg_value(wScore)) << " "
1157 << std::setw(6) << to_cp(eg_value(wScore)) << " \n";
1160 TraceStream << std::setw(20) << name << " | " << std::noshowpos
1161 << std::setw(5) << to_cp(mg_value(wScore)) << " "
1162 << std::setw(5) << to_cp(eg_value(wScore)) << " | "
1163 << std::setw(5) << to_cp(mg_value(bScore)) << " "
1164 << std::setw(5) << to_cp(eg_value(bScore)) << " | "
1166 << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " "
1167 << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n";