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(11, 20);
160 const Score QueenOn7thBonus = make_score( 3, 8);
162 // Rooks and queens attacking pawns on the same rank
163 const Score RookOnPawnBonus = make_score(10, 28);
164 const Score QueenOnPawnBonus = make_score( 4, 20);
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 bishop with pawns on the same coloured squares
175 const Score BishopPawnsPenalty = make_score(8, 12);
177 // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
178 // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
179 // happen in Chess960 games.
180 const Score TrappedBishopA1H1Penalty = make_score(100, 100);
182 // Penalty for an undefended bishop or knight
183 const Score UndefendedMinorPenalty = make_score(25, 10);
185 // The SpaceMask[Color] contains the area of the board which is considered
186 // by the space evaluation. In the middle game, each side is given a bonus
187 // based on how many squares inside this area are safe and available for
188 // friendly minor pieces.
189 const Bitboard SpaceMask[] = {
190 (1ULL << SQ_C2) | (1ULL << SQ_D2) | (1ULL << SQ_E2) | (1ULL << SQ_F2) |
191 (1ULL << SQ_C3) | (1ULL << SQ_D3) | (1ULL << SQ_E3) | (1ULL << SQ_F3) |
192 (1ULL << SQ_C4) | (1ULL << SQ_D4) | (1ULL << SQ_E4) | (1ULL << SQ_F4),
193 (1ULL << SQ_C7) | (1ULL << SQ_D7) | (1ULL << SQ_E7) | (1ULL << SQ_F7) |
194 (1ULL << SQ_C6) | (1ULL << SQ_D6) | (1ULL << SQ_E6) | (1ULL << SQ_F6) |
195 (1ULL << SQ_C5) | (1ULL << SQ_D5) | (1ULL << SQ_E5) | (1ULL << SQ_F5)
198 // King danger constants and variables. The king danger scores are taken
199 // from the KingDangerTable[]. Various little "meta-bonuses" measuring
200 // the strength of the enemy attack are added up into an integer, which
201 // is used as an index to KingDangerTable[].
203 // KingAttackWeights[PieceType] contains king attack weights by piece type
204 const int KingAttackWeights[] = { 0, 0, 2, 2, 3, 5 };
206 // Bonuses for enemy's safe checks
207 const int QueenContactCheckBonus = 6;
208 const int RookContactCheckBonus = 4;
209 const int QueenCheckBonus = 3;
210 const int RookCheckBonus = 2;
211 const int BishopCheckBonus = 1;
212 const int KnightCheckBonus = 1;
214 // InitKingDanger[Square] contains penalties based on the position of the
215 // defending king, indexed by king's square (from white's point of view).
216 const int InitKingDanger[] = {
217 2, 0, 2, 5, 5, 2, 0, 2,
218 2, 2, 4, 8, 8, 4, 2, 2,
219 7, 10, 12, 12, 12, 12, 10, 7,
220 15, 15, 15, 15, 15, 15, 15, 15,
221 15, 15, 15, 15, 15, 15, 15, 15,
222 15, 15, 15, 15, 15, 15, 15, 15,
223 15, 15, 15, 15, 15, 15, 15, 15,
224 15, 15, 15, 15, 15, 15, 15, 15
227 // KingDangerTable[Color][attackUnits] contains the actual king danger
228 // weighted scores, indexed by color and by a calculated integer number.
229 Score KingDangerTable[COLOR_NB][128];
231 // TracedTerms[Color][PieceType || TracedType] contains a breakdown of the
232 // evaluation terms, used when tracing.
233 Score TracedScores[COLOR_NB][16];
234 std::stringstream TraceStream;
237 PST = 8, IMBALANCE = 9, MOBILITY = 10, THREAT = 11,
238 PASSED = 12, UNSTOPPABLE = 13, SPACE = 14, TOTAL = 15
241 // Function prototypes
243 Value do_evaluate(const Position& pos, Value& margin);
246 void init_eval_info(const Position& pos, EvalInfo& ei);
248 template<Color Us, bool Trace>
249 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility);
251 template<Color Us, bool Trace>
252 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]);
255 Score evaluate_threats(const Position& pos, EvalInfo& ei);
258 int evaluate_space(const Position& pos, EvalInfo& ei);
261 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
263 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
265 Value interpolate(const Score& v, Phase ph, ScaleFactor sf);
266 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
267 double to_cp(Value v);
268 void trace_add(int idx, Score term_w, Score term_b = SCORE_ZERO);
269 void trace_row(const char* name, int idx);
275 /// evaluate() is the main evaluation function. It always computes two
276 /// values, an endgame score and a middle game score, and interpolates
277 /// between them based on the remaining material.
279 Value evaluate(const Position& pos, Value& margin) {
280 return do_evaluate<false>(pos, margin);
284 /// init() computes evaluation weights from the corresponding UCI parameters
285 /// and setup king tables.
289 Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
290 Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
291 Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
292 Weights[KingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
293 Weights[KingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
295 const int MaxSlope = 30;
296 const int Peak = 1280;
298 for (int t = 0, i = 1; i < 100; i++)
300 t = std::min(Peak, std::min(int(0.4 * i * i), t + MaxSlope));
302 KingDangerTable[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]);
303 KingDangerTable[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]);
308 /// trace() is like evaluate() but instead of a value returns a string suitable
309 /// to be print on stdout with the detailed descriptions and values of each
310 /// evaluation term. Used mainly for debugging.
312 std::string trace(const Position& pos) {
317 Search::RootColor = pos.side_to_move();
320 TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
321 memset(TracedScores, 0, 2 * 16 * sizeof(Score));
323 do_evaluate<true>(pos, margin);
325 totals = TraceStream.str();
328 TraceStream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
329 << " | MG EG | MG EG | MG EG \n"
330 << "---------------------+-------------+-------------+---------------\n";
332 trace_row("Material, PST, Tempo", PST);
333 trace_row("Material imbalance", IMBALANCE);
334 trace_row("Pawns", PAWN);
335 trace_row("Knights", KNIGHT);
336 trace_row("Bishops", BISHOP);
337 trace_row("Rooks", ROOK);
338 trace_row("Queens", QUEEN);
339 trace_row("Mobility", MOBILITY);
340 trace_row("King safety", KING);
341 trace_row("Threats", THREAT);
342 trace_row("Passed pawns", PASSED);
343 trace_row("Unstoppable pawns", UNSTOPPABLE);
344 trace_row("Space", SPACE);
346 TraceStream << "---------------------+-------------+-------------+---------------\n";
347 trace_row("Total", TOTAL);
348 TraceStream << totals;
350 return TraceStream.str();
359 Value do_evaluate(const Position& pos, Value& margin) {
361 assert(!pos.checkers());
364 Value margins[COLOR_NB];
365 Score score, mobilityWhite, mobilityBlack;
366 Thread* th = pos.this_thread();
368 // margins[] store the uncertainty estimation of position's evaluation
369 // that typically is used by the search for pruning decisions.
370 margins[WHITE] = margins[BLACK] = VALUE_ZERO;
372 // Initialize score by reading the incrementally updated scores included
373 // in the position object (material + piece square tables) and adding
374 // Tempo bonus. Score is computed from the point of view of white.
375 score = pos.psq_score() + (pos.side_to_move() == WHITE ? Tempo : -Tempo);
377 // Probe the material hash table
378 ei.mi = Material::probe(pos, th->materialTable, th->endgames);
379 score += ei.mi->material_value();
381 // If we have a specialized evaluation function for the current material
382 // configuration, call it and return.
383 if (ei.mi->specialized_eval_exists())
386 return ei.mi->evaluate(pos);
389 // Probe the pawn hash table
390 ei.pi = Pawns::probe(pos, th->pawnsTable);
391 score += ei.pi->pawns_value();
393 // Initialize attack and king safety bitboards
394 init_eval_info<WHITE>(pos, ei);
395 init_eval_info<BLACK>(pos, ei);
397 // Evaluate pieces and mobility
398 score += evaluate_pieces_of_color<WHITE, Trace>(pos, ei, mobilityWhite)
399 - evaluate_pieces_of_color<BLACK, Trace>(pos, ei, mobilityBlack);
401 score += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
403 // Evaluate kings after all other pieces because we need complete attack
404 // information when computing the king safety evaluation.
405 score += evaluate_king<WHITE, Trace>(pos, ei, margins)
406 - evaluate_king<BLACK, Trace>(pos, ei, margins);
408 // Evaluate tactical threats, we need full attack information including king
409 score += evaluate_threats<WHITE>(pos, ei)
410 - evaluate_threats<BLACK>(pos, ei);
412 // Evaluate passed pawns, we need full attack information including king
413 score += evaluate_passed_pawns<WHITE>(pos, ei)
414 - evaluate_passed_pawns<BLACK>(pos, ei);
416 // If one side has only a king, check whether exists any unstoppable passed pawn
417 if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
418 score += evaluate_unstoppable_pawns(pos, ei);
420 // Evaluate space for both sides, only in middle-game.
421 if (ei.mi->space_weight())
423 int s = evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei);
424 score += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]);
427 // Scale winning side if position is more drawish that what it appears
428 ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE)
429 : ei.mi->scale_factor(pos, BLACK);
431 // If we don't already have an unusual scale factor, check for opposite
432 // colored bishop endgames, and use a lower scale for those.
433 if ( ei.mi->game_phase() < PHASE_MIDGAME
434 && pos.opposite_bishops()
435 && sf == SCALE_FACTOR_NORMAL)
437 // Only the two bishops ?
438 if ( pos.non_pawn_material(WHITE) == BishopValueMg
439 && pos.non_pawn_material(BLACK) == BishopValueMg)
441 // Check for KBP vs KB with only a single pawn that is almost
442 // certainly a draw or at least two pawns.
443 bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
444 sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
447 // Endgame with opposite-colored bishops, but also other pieces. Still
448 // a bit drawish, but not as drawish as with only the two bishops.
449 sf = ScaleFactor(50);
452 margin = margins[pos.side_to_move()];
453 Value v = interpolate(score, ei.mi->game_phase(), sf);
455 // In case of tracing add all single evaluation contributions for both white and black
458 trace_add(PST, pos.psq_score());
459 trace_add(IMBALANCE, ei.mi->material_value());
460 trace_add(PAWN, ei.pi->pawns_value());
461 trace_add(MOBILITY, apply_weight(mobilityWhite, Weights[Mobility]), apply_weight(mobilityBlack, Weights[Mobility]));
462 trace_add(THREAT, evaluate_threats<WHITE>(pos, ei), evaluate_threats<BLACK>(pos, ei));
463 trace_add(PASSED, evaluate_passed_pawns<WHITE>(pos, ei), evaluate_passed_pawns<BLACK>(pos, ei));
464 trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns(pos, ei));
465 Score w = make_score(ei.mi->space_weight() * evaluate_space<WHITE>(pos, ei), 0);
466 Score b = make_score(ei.mi->space_weight() * evaluate_space<BLACK>(pos, ei), 0);
467 trace_add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
468 trace_add(TOTAL, score);
469 TraceStream << "\nUncertainty margin: White: " << to_cp(margins[WHITE])
470 << ", Black: " << to_cp(margins[BLACK])
471 << "\nScaling: " << std::noshowpos
472 << std::setw(6) << 100.0 * ei.mi->game_phase() / 128.0 << "% MG, "
473 << std::setw(6) << 100.0 * (1.0 - ei.mi->game_phase() / 128.0) << "% * "
474 << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
475 << "Total evaluation: " << to_cp(v);
478 return pos.side_to_move() == WHITE ? v : -v;
482 // init_eval_info() initializes king bitboards for given color adding
483 // pawn attacks. To be done at the beginning of the evaluation.
486 void init_eval_info(const Position& pos, EvalInfo& ei) {
488 const Color Them = (Us == WHITE ? BLACK : WHITE);
490 Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
491 ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
493 // Init king safety tables only if we are going to use them
494 if ( pos.piece_count(Us, QUEEN)
495 && pos.non_pawn_material(Us) > QueenValueMg + PawnValueMg)
497 ei.kingRing[Them] = (b | (Us == WHITE ? b >> 8 : b << 8));
498 b &= ei.attackedBy[Us][PAWN];
499 ei.kingAttackersCount[Us] = b ? popcount<Max15>(b) / 2 : 0;
500 ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
502 ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0;
506 // evaluate_outposts() evaluates bishop and knight outposts squares
508 template<PieceType Piece, Color Us>
509 Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
511 const Color Them = (Us == WHITE ? BLACK : WHITE);
513 assert (Piece == BISHOP || Piece == KNIGHT);
515 // Initial bonus based on square
516 Value bonus = OutpostBonus[Piece == BISHOP][relative_square(Us, s)];
518 // Increase bonus if supported by pawn, especially if the opponent has
519 // no minor piece which can exchange the outpost piece.
520 if (bonus && (ei.attackedBy[Us][PAWN] & s))
522 if ( !pos.pieces(Them, KNIGHT)
523 && !(same_color_squares(s) & pos.pieces(Them, BISHOP)))
524 bonus += bonus + bonus / 2;
528 return make_score(bonus, bonus);
532 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
534 template<PieceType Piece, Color Us, bool Trace>
535 Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
541 Score score = SCORE_ZERO;
543 const Color Them = (Us == WHITE ? BLACK : WHITE);
544 const Square* pl = pos.piece_list(Us, Piece);
546 ei.attackedBy[Us][Piece] = 0;
548 while ((s = *pl++) != SQ_NONE)
550 // Find attacked squares, including x-ray attacks for bishops and rooks
551 if (Piece == KNIGHT || Piece == QUEEN)
552 b = pos.attacks_from<Piece>(s);
553 else if (Piece == BISHOP)
554 b = attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(Us, QUEEN));
555 else if (Piece == ROOK)
556 b = attacks_bb<ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN));
560 ei.attackedBy[Us][Piece] |= b;
562 if (b & ei.kingRing[Them])
564 ei.kingAttackersCount[Us]++;
565 ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
566 Bitboard bb = (b & ei.attackedBy[Them][KING]);
568 ei.kingAdjacentZoneAttacksCount[Us] += popcount<Max15>(bb);
571 mob = (Piece != QUEEN ? popcount<Max15>(b & mobilityArea)
572 : popcount<Full >(b & mobilityArea));
574 mobility += MobilityBonus[Piece][mob];
576 // Decrease score if we are attacked by an enemy pawn. Remaining part
577 // of threat evaluation must be done later when we have full attack info.
578 if (ei.attackedBy[Them][PAWN] & s)
579 score -= ThreatenedByPawnPenalty[Piece];
581 // Otherwise give a bonus if we are a bishop and can pin a piece or
582 // can give a discovered check through an x-ray attack.
583 else if ( Piece == BISHOP
584 && (PseudoAttacks[Piece][pos.king_square(Them)] & s)
585 && !more_than_one(BetweenBB[s][pos.king_square(Them)] & pos.pieces()))
586 score += BishopPinBonus;
588 // Penalty for bishop with same coloured pawns
590 score -= BishopPawnsPenalty * ei.pi->pawns_on_same_color_squares(Us, s);
592 // Bishop and knight outposts squares
593 if ( (Piece == BISHOP || Piece == KNIGHT)
594 && !(pos.pieces(Them, PAWN) & attack_span_mask(Us, s)))
595 score += evaluate_outposts<Piece, Us>(pos, ei, s);
597 if ((Piece == ROOK || Piece == QUEEN) && relative_rank(Us, s) >= RANK_5)
599 // Major piece on 7th rank
600 if ( relative_rank(Us, s) == RANK_7
601 && relative_rank(Us, pos.king_square(Them)) == RANK_8)
602 score += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
604 // Major piece attacking pawns on the same rank
605 Bitboard pawns = pos.pieces(Them, PAWN) & rank_bb(s);
607 score += (Piece == ROOK ? RookOnPawnBonus
608 : QueenOnPawnBonus) * popcount<Max15>(pawns);
611 // Special extra evaluation for bishops
612 if (Piece == BISHOP && pos.is_chess960())
614 // An important Chess960 pattern: A cornered bishop blocked by
615 // a friendly pawn diagonally in front of it is a very serious
616 // problem, especially when that pawn is also blocked.
617 if (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1))
619 Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
620 if (pos.piece_on(s + d) == make_piece(Us, PAWN))
622 if (!pos.is_empty(s + d + pawn_push(Us)))
623 score -= 2*TrappedBishopA1H1Penalty;
624 else if (pos.piece_on(s + 2*d) == make_piece(Us, PAWN))
625 score -= TrappedBishopA1H1Penalty;
627 score -= TrappedBishopA1H1Penalty / 2;
632 // Special extra evaluation for rooks
635 // Open and half-open files
637 if (ei.pi->file_is_half_open(Us, f))
639 if (ei.pi->file_is_half_open(Them, f))
640 score += RookOpenFileBonus;
642 score += RookHalfOpenFileBonus;
645 if (mob > 6 || ei.pi->file_is_half_open(Us, f))
648 ksq = pos.king_square(Us);
650 // Penalize rooks which are trapped inside a king. Penalize more if
651 // king has lost right to castle.
652 if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
653 && rank_of(ksq) == rank_of(s)
654 && relative_rank(Us, ksq) == RANK_1
655 && !ei.pi->has_open_file_on_side(Us, file_of(ksq), file_of(ksq) < FILE_E))
656 score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
657 : (TrappedRookPenalty - mob * 16), 0);
662 TracedScores[Us][Piece] = score;
668 // evaluate_threats<>() assigns bonuses according to the type of attacking piece
669 // and the type of attacked one.
672 Score evaluate_threats(const Position& pos, EvalInfo& ei) {
674 const Color Them = (Us == WHITE ? BLACK : WHITE);
676 Bitboard b, undefendedMinors, weakEnemies;
677 Score score = SCORE_ZERO;
679 // Undefended minors get penalized even if not under attack
680 undefendedMinors = pos.pieces(Them, BISHOP, KNIGHT)
681 & ~ei.attackedBy[Them][ALL_PIECES];
683 if (undefendedMinors)
684 score += UndefendedMinorPenalty;
686 // Enemy pieces not defended by a pawn and under our attack
687 weakEnemies = pos.pieces(Them)
688 & ~ei.attackedBy[Them][PAWN]
689 & ei.attackedBy[Us][ALL_PIECES];
694 // Add bonus according to type of attacked enemy piece and to the
695 // type of attacking piece, from knights to queens. Kings are not
696 // considered because are already handled in king evaluation.
697 for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
699 b = ei.attackedBy[Us][pt1] & weakEnemies;
701 for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
702 if (b & pos.pieces(pt2))
703 score += ThreatBonus[pt1][pt2];
709 // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
710 // pieces of a given color.
712 template<Color Us, bool Trace>
713 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) {
715 const Color Them = (Us == WHITE ? BLACK : WHITE);
717 Score score = mobility = SCORE_ZERO;
719 // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
720 const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces(Us, PAWN, KING));
722 score += evaluate_pieces<KNIGHT, Us, Trace>(pos, ei, mobility, mobilityArea);
723 score += evaluate_pieces<BISHOP, Us, Trace>(pos, ei, mobility, mobilityArea);
724 score += evaluate_pieces<ROOK, Us, Trace>(pos, ei, mobility, mobilityArea);
725 score += evaluate_pieces<QUEEN, Us, Trace>(pos, ei, mobility, mobilityArea);
727 // Sum up all attacked squares
728 ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
729 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
730 | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
735 // evaluate_king<>() assigns bonuses and penalties to a king of a given color
737 template<Color Us, bool Trace>
738 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
740 const Color Them = (Us == WHITE ? BLACK : WHITE);
742 Bitboard undefended, b, b1, b2, safe;
744 const Square ksq = pos.king_square(Us);
746 // King shelter and enemy pawns storm
747 Score score = ei.pi->king_safety<Us>(pos, ksq);
749 // King safety. This is quite complicated, and is almost certainly far
750 // from optimally tuned.
751 if ( ei.kingAttackersCount[Them] >= 2
752 && ei.kingAdjacentZoneAttacksCount[Them])
754 // Find the attacked squares around the king which has no defenders
755 // apart from the king itself
756 undefended = ei.attackedBy[Them][ALL_PIECES] & ei.attackedBy[Us][KING];
757 undefended &= ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
758 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
759 | ei.attackedBy[Us][QUEEN]);
761 // Initialize the 'attackUnits' variable, which is used later on as an
762 // index to the KingDangerTable[] array. The initial value is based on
763 // the number and types of the enemy's attacking pieces, the number of
764 // attacked and undefended squares around our king, the square of the
765 // king, and the quality of the pawn shelter.
766 attackUnits = std::min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
767 + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount<Max15>(undefended))
768 + InitKingDanger[relative_square(Us, ksq)]
769 - mg_value(score) / 32;
771 // Analyse enemy's safe queen contact checks. First find undefended
772 // squares around the king attacked by enemy queen...
773 b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
776 // ...then remove squares not supported by another enemy piece
777 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
778 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
780 attackUnits += QueenContactCheckBonus
782 * (Them == pos.side_to_move() ? 2 : 1);
785 // Analyse enemy's safe rook contact checks. First find undefended
786 // squares around the king attacked by enemy rooks...
787 b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
789 // Consider only squares where the enemy rook gives check
790 b &= PseudoAttacks[ROOK][ksq];
794 // ...then remove squares not supported by another enemy piece
795 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
796 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]);
798 attackUnits += RookContactCheckBonus
800 * (Them == pos.side_to_move() ? 2 : 1);
803 // Analyse enemy's safe distance checks for sliders and knights
804 safe = ~(pos.pieces(Them) | ei.attackedBy[Us][ALL_PIECES]);
806 b1 = pos.attacks_from<ROOK>(ksq) & safe;
807 b2 = pos.attacks_from<BISHOP>(ksq) & safe;
809 // Enemy queen safe checks
810 b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
812 attackUnits += QueenCheckBonus * popcount<Max15>(b);
814 // Enemy rooks safe checks
815 b = b1 & ei.attackedBy[Them][ROOK];
817 attackUnits += RookCheckBonus * popcount<Max15>(b);
819 // Enemy bishops safe checks
820 b = b2 & ei.attackedBy[Them][BISHOP];
822 attackUnits += BishopCheckBonus * popcount<Max15>(b);
824 // Enemy knights safe checks
825 b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
827 attackUnits += KnightCheckBonus * popcount<Max15>(b);
829 // To index KingDangerTable[] attackUnits must be in [0, 99] range
830 attackUnits = std::min(99, std::max(0, attackUnits));
832 // Finally, extract the king danger score from the KingDangerTable[]
833 // array and subtract the score from evaluation. Set also margins[]
834 // value that will be used for pruning because this value can sometimes
835 // be very big, and so capturing a single attacking piece can therefore
836 // result in a score change far bigger than the value of the captured piece.
837 score -= KingDangerTable[Us == Search::RootColor][attackUnits];
838 margins[Us] += mg_value(KingDangerTable[Us == Search::RootColor][attackUnits]);
842 TracedScores[Us][KING] = score;
848 // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
851 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
853 const Color Them = (Us == WHITE ? BLACK : WHITE);
855 Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
856 Score score = SCORE_ZERO;
858 b = ei.pi->passed_pawns(Us);
864 Square s = pop_lsb(&b);
866 assert(pos.pawn_is_passed(Us, s));
868 int r = int(relative_rank(Us, s) - RANK_2);
869 int rr = r * (r - 1);
871 // Base bonus based on rank
872 Value mbonus = Value(20 * rr);
873 Value ebonus = Value(10 * (rr + r + 1));
877 Square blockSq = s + pawn_push(Us);
879 // Adjust bonus based on kings proximity
880 ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 5 * rr);
881 ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 2 * rr);
883 // If blockSq is not the queening square then consider also a second push
884 if (rank_of(blockSq) != (Us == WHITE ? RANK_8 : RANK_1))
885 ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
887 // If the pawn is free to advance, increase bonus
888 if (pos.is_empty(blockSq))
890 squaresToQueen = forward_bb(Us, s);
891 defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES];
893 // If there is an enemy rook or queen attacking the pawn from behind,
894 // add all X-ray attacks by the rook or queen. Otherwise consider only
895 // the squares in the pawn's path attacked or occupied by the enemy.
896 if ( (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN))
897 && (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN) & pos.attacks_from<ROOK>(s)))
898 unsafeSquares = squaresToQueen;
900 unsafeSquares = squaresToQueen & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
902 // Default bonus for the empty square in front
903 int bonusMultiplier = 3;
905 if ((defendedSquares & SquareBB[blockSq]) != 0)
907 // Defending the square in front
908 bonusMultiplier += 2;
909 if ((unsafeSquares & defendedSquares) == unsafeSquares)
910 // Defending all the attacked squares
911 // bigger bonus if we are defending everything
912 bonusMultiplier += (squaresToQueen == defendedSquares) ? 4 : 2;
915 if ((unsafeSquares & SquareBB[blockSq]) == 0)
917 // The square infront isn't attacked
918 bonusMultiplier += 6;
920 bonusMultiplier += 6;
923 Value bonus = Value(rr * bonusMultiplier);
929 // Increase the bonus if the passed pawn is supported by a friendly pawn
930 // on the same rank and a bit smaller if it's on the previous rank.
931 supportingPawns = pos.pieces(Us, PAWN) & adjacent_files_bb(file_of(s));
932 if (supportingPawns & rank_bb(s))
933 ebonus += Value(r * 20);
935 else if (supportingPawns & rank_bb(s - pawn_push(Us)))
936 ebonus += Value(r * 12);
938 // Rook pawns are a special case: They are sometimes worse, and
939 // sometimes better than other passed pawns. It is difficult to find
940 // good rules for determining whether they are good or bad. For now,
941 // we try the following: Increase the value for rook pawns if the
942 // other side has no pieces apart from a knight, and decrease the
943 // value if the other side has a rook or queen.
944 if (file_of(s) == FILE_A || file_of(s) == FILE_H)
946 if (pos.non_pawn_material(Them) <= KnightValueMg)
947 ebonus += ebonus / 4;
948 else if (pos.pieces(Them, ROOK, QUEEN))
949 ebonus -= ebonus / 4;
951 score += make_score(mbonus, ebonus);
955 // Add the scores to the middle game and endgame eval
956 return apply_weight(score, Weights[PassedPawns]);
960 // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides, this is quite
961 // conservative and returns a winning score only when we are very sure that the pawn is winning.
963 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
965 Bitboard b, b2, blockers, supporters, queeningPath, candidates;
966 Square s, blockSq, queeningSquare;
967 Color c, winnerSide, loserSide;
968 bool pathDefended, opposed;
969 int pliesToGo, movesToGo, oppMovesToGo, sacptg, blockersCount, minKingDist, kingptg, d;
970 int pliesToQueen[] = { 256, 256 };
972 // Step 1. Hunt for unstoppable passed pawns. If we find at least one,
973 // record how many plies are required for promotion.
974 for (c = WHITE; c <= BLACK; c++)
976 // Skip if other side has non-pawn pieces
977 if (pos.non_pawn_material(~c))
980 b = ei.pi->passed_pawns(c);
985 queeningSquare = relative_square(c, file_of(s) | RANK_8);
986 queeningPath = forward_bb(c, s);
988 // Compute plies to queening and check direct advancement
989 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(c, s) == RANK_2);
990 oppMovesToGo = square_distance(pos.king_square(~c), queeningSquare) - int(c != pos.side_to_move());
991 pathDefended = ((ei.attackedBy[c][ALL_PIECES] & queeningPath) == queeningPath);
993 if (movesToGo >= oppMovesToGo && !pathDefended)
996 // Opponent king cannot block because path is defended and position
997 // is not in check. So only friendly pieces can be blockers.
998 assert(!pos.checkers());
999 assert((queeningPath & pos.pieces()) == (queeningPath & pos.pieces(c)));
1001 // Add moves needed to free the path from friendly pieces and retest condition
1002 movesToGo += popcount<Max15>(queeningPath & pos.pieces(c));
1004 if (movesToGo >= oppMovesToGo && !pathDefended)
1007 pliesToGo = 2 * movesToGo - int(c == pos.side_to_move());
1008 pliesToQueen[c] = std::min(pliesToQueen[c], pliesToGo);
1012 // Step 2. If either side cannot promote at least three plies before the other side then situation
1013 // becomes too complex and we give up. Otherwise we determine the possibly "winning side"
1014 if (abs(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3)
1017 winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK);
1018 loserSide = ~winnerSide;
1020 // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
1021 b = candidates = pos.pieces(loserSide, PAWN);
1027 // Compute plies from queening
1028 queeningSquare = relative_square(loserSide, file_of(s) | RANK_8);
1029 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
1030 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
1032 // Check if (without even considering any obstacles) we're too far away or doubled
1033 if ( pliesToQueen[winnerSide] + 3 <= pliesToGo
1034 || (forward_bb(loserSide, s) & pos.pieces(loserSide, PAWN)))
1038 // If any candidate is already a passed pawn it _may_ promote in time. We give up.
1039 if (candidates & ei.pi->passed_pawns(loserSide))
1042 // Step 4. Check new passed pawn creation through king capturing and pawn sacrifices
1048 sacptg = blockersCount = 0;
1049 minKingDist = kingptg = 256;
1051 // Compute plies from queening
1052 queeningSquare = relative_square(loserSide, file_of(s) | RANK_8);
1053 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
1054 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
1056 // Generate list of blocking pawns and supporters
1057 supporters = adjacent_files_bb(file_of(s)) & candidates;
1058 opposed = forward_bb(loserSide, s) & pos.pieces(winnerSide, PAWN);
1059 blockers = passed_pawn_mask(loserSide, s) & pos.pieces(winnerSide, PAWN);
1063 // How many plies does it take to remove all the blocking pawns?
1066 blockSq = pop_lsb(&blockers);
1069 // Check pawns that can give support to overcome obstacle, for instance
1070 // black pawns: a4, b4 white: b2 then pawn in b4 is giving support.
1073 b2 = supporters & in_front_bb(winnerSide, blockSq + pawn_push(winnerSide));
1075 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1077 d = square_distance(blockSq, pop_lsb(&b2)) - 2;
1078 movesToGo = std::min(movesToGo, d);
1082 // Check pawns that can be sacrificed against the blocking pawn
1083 b2 = attack_span_mask(winnerSide, blockSq) & candidates & ~(1ULL << s);
1085 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1087 d = square_distance(blockSq, pop_lsb(&b2)) - 2;
1088 movesToGo = std::min(movesToGo, d);
1091 // If obstacle can be destroyed with an immediate pawn exchange / sacrifice,
1092 // it's not a real obstacle and we have nothing to add to pliesToGo.
1096 // Plies needed to sacrifice against all the blocking pawns
1097 sacptg += movesToGo * 2;
1100 // Plies needed for the king to capture all the blocking pawns
1101 d = square_distance(pos.king_square(loserSide), blockSq);
1102 minKingDist = std::min(minKingDist, d);
1103 kingptg = (minKingDist + blockersCount) * 2;
1106 // Check if pawn sacrifice plan _may_ save the day
1107 if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg)
1110 // Check if king capture plan _may_ save the day (contains some false positives)
1111 if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg)
1115 // Winning pawn is unstoppable and will promote as first, return big score
1116 Score score = make_score(0, (Value) 1280 - 32 * pliesToQueen[winnerSide]);
1117 return winnerSide == WHITE ? score : -score;
1121 // evaluate_space() computes the space evaluation for a given side. The
1122 // space evaluation is a simple bonus based on the number of safe squares
1123 // available for minor pieces on the central four files on ranks 2--4. Safe
1124 // squares one, two or three squares behind a friendly pawn are counted
1125 // twice. Finally, the space bonus is scaled by a weight taken from the
1126 // material hash table. The aim is to improve play on game opening.
1128 int evaluate_space(const Position& pos, EvalInfo& ei) {
1130 const Color Them = (Us == WHITE ? BLACK : WHITE);
1132 // Find the safe squares for our pieces inside the area defined by
1133 // SpaceMask[]. A square is unsafe if it is attacked by an enemy
1134 // pawn, or if it is undefended and attacked by an enemy piece.
1135 Bitboard safe = SpaceMask[Us]
1136 & ~pos.pieces(Us, PAWN)
1137 & ~ei.attackedBy[Them][PAWN]
1138 & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
1140 // Find all squares which are at most three squares behind some friendly pawn
1141 Bitboard behind = pos.pieces(Us, PAWN);
1142 behind |= (Us == WHITE ? behind >> 8 : behind << 8);
1143 behind |= (Us == WHITE ? behind >> 16 : behind << 16);
1145 // Since SpaceMask[Us] is fully on our half of the board
1146 assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);
1148 // Count safe + (behind & safe) with a single popcount
1149 return popcount<Full>((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
1153 // interpolate() interpolates between a middle game and an endgame score,
1154 // based on game phase. It also scales the return value by a ScaleFactor array.
1156 Value interpolate(const Score& v, Phase ph, ScaleFactor sf) {
1158 assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
1159 assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
1160 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1162 int ev = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
1163 int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128;
1164 return Value((result + GrainSize / 2) & ~(GrainSize - 1));
1168 // weight_option() computes the value of an evaluation weight, by combining
1169 // two UCI-configurable weights (midgame and endgame) with an internal weight.
1171 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
1173 // Scale option value from 100 to 256
1174 int mg = Options[mgOpt] * 256 / 100;
1175 int eg = Options[egOpt] * 256 / 100;
1177 return apply_weight(make_score(mg, eg), internalWeight);
1181 // A couple of little helpers used by tracing code, to_cp() converts a value to
1182 // a double in centipawns scale, trace_add() stores white and black scores.
1184 double to_cp(Value v) { return double(v) / double(PawnValueMg); }
1186 void trace_add(int idx, Score wScore, Score bScore) {
1188 TracedScores[WHITE][idx] = wScore;
1189 TracedScores[BLACK][idx] = bScore;
1193 // trace_row() is an helper function used by tracing code to register the
1194 // values of a single evaluation term.
1196 void trace_row(const char* name, int idx) {
1198 Score wScore = TracedScores[WHITE][idx];
1199 Score bScore = TracedScores[BLACK][idx];
1202 case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL:
1203 TraceStream << std::setw(20) << name << " | --- --- | --- --- | "
1204 << std::setw(6) << to_cp(mg_value(wScore)) << " "
1205 << std::setw(6) << to_cp(eg_value(wScore)) << " \n";
1208 TraceStream << std::setw(20) << name << " | " << std::noshowpos
1209 << std::setw(5) << to_cp(mg_value(wScore)) << " "
1210 << std::setw(5) << to_cp(eg_value(wScore)) << " | "
1211 << std::setw(5) << to_cp(mg_value(bScore)) << " "
1212 << std::setw(5) << to_cp(eg_value(bScore)) << " | "
1214 << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " "
1215 << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n";