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 };
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(252, 344), S(216, 266), S(46, 0)
94 // MobilityBonus[PieceType][attacked] contains mobility bonuses for middle and
95 // end game, indexed by piece type and number of attacked squares not occupied
96 // by friendly pieces.
97 const Score MobilityBonus[][32] = {
99 { S(-38,-33), S(-25,-23), S(-12,-13), S( 0, -3), S(12, 7), S(25, 17), // Knights
100 S( 31, 22), S( 38, 27), S( 38, 27) },
101 { S(-25,-30), S(-11,-16), S( 3, -2), S(17, 12), S(31, 26), S(45, 40), // Bishops
102 S( 57, 52), S( 65, 60), S( 71, 65), S(74, 69), S(76, 71), S(78, 73),
103 S( 79, 74), S( 80, 75), S( 81, 76), S(81, 76) },
104 { S(-20,-36), S(-14,-19), S( -8, -3), S(-2, 13), S( 4, 29), S(10, 46), // Rooks
105 S( 14, 62), S( 19, 79), S( 23, 95), S(26,106), S(27,111), S(28,114),
106 S( 29,116), S( 30,117), S( 31,118), S(32,118) },
107 { S(-10,-18), S( -8,-13), S( -6, -7), S(-3, -2), S(-1, 3), S( 1, 8), // Queens
108 S( 3, 13), S( 5, 19), S( 8, 23), S(10, 27), S(12, 32), S(15, 34),
109 S( 16, 35), S( 17, 35), S( 18, 35), S(20, 35), S(20, 35), S(20, 35),
110 S( 20, 35), S( 20, 35), S( 20, 35), S(20, 35), S(20, 35), S(20, 35),
111 S( 20, 35), S( 20, 35), S( 20, 35), S(20, 35), S(20, 35), S(20, 35),
112 S( 20, 35), S( 20, 35) }
115 // OutpostBonus[PieceType][Square] contains outpost bonuses of knights and
116 // bishops, indexed by piece type and square (from white's point of view).
117 const Value OutpostBonus[][SQUARE_NB] = {
120 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Knights
121 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
122 V(0), V(0), V(4), V(8), V(8), V(4), V(0), V(0),
123 V(0), V(4),V(17),V(26),V(26),V(17), V(4), V(0),
124 V(0), V(8),V(26),V(35),V(35),V(26), V(8), V(0),
125 V(0), V(4),V(17),V(17),V(17),V(17), V(4), V(0) },
127 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Bishops
128 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
129 V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0),
130 V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0),
131 V(0),V(10),V(21),V(21),V(21),V(21),V(10), V(0),
132 V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0) }
135 // ThreatBonus[attacking][attacked] contains threat bonuses according to
136 // which piece type attacks which one.
137 const Score ThreatBonus[][PIECE_TYPE_NB] = {
139 { S(0, 0), S( 7, 39), S( 0, 0), S(24, 49), S(41,100), S(41,100) }, // KNIGHT
140 { S(0, 0), S( 7, 39), S(24, 49), S( 0, 0), S(41,100), S(41,100) }, // BISHOP
141 { S(0, 0), S( 0, 22), S(15, 49), S(15, 49), S( 0, 0), S(24, 49) }, // ROOK
142 { S(0, 0), S(15, 39), S(15, 39), S(15, 39), S(15, 39), S( 0, 0) } // QUEEN
145 // ThreatenedByPawnPenalty[PieceType] contains a penalty according to which
146 // piece type is attacked by an enemy pawn.
147 const Score ThreatenedByPawnPenalty[] = {
148 S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
153 const Score BishopPinBonus = make_score(66, 11);
155 // Bonus for having the side to move (modified by Joona Kiiski)
156 const Score Tempo = make_score(24, 11);
158 // Rooks and queens on the 7th rank
159 const Score RookOn7thBonus = make_score(3, 20);
160 const Score QueenOn7thBonus = make_score(1, 8);
162 // Rooks and queens attacking pawns on the same rank
163 const Score RookOnPawnBonus = make_score(3, 48);
164 const Score QueenOnPawnBonus = make_score(1, 40);
166 // Rooks on open files (modified by Joona Kiiski)
167 const Score RookOpenFileBonus = make_score(43, 21);
168 const Score RookHalfOpenFileBonus = make_score(19, 10);
170 // Penalty for rooks trapped inside a friendly king which has lost the
172 const Value TrappedRookPenalty = Value(180);
174 // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
175 // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
176 // happen in Chess960 games.
177 const Score TrappedBishopA1H1Penalty = make_score(100, 100);
179 // Penalty for an undefended bishop or knight
180 const Score UndefendedMinorPenalty = make_score(25, 10);
182 // The SpaceMask[Color] contains the area of the board which is considered
183 // by the space evaluation. In the middle game, each side is given a bonus
184 // based on how many squares inside this area are safe and available for
185 // friendly minor pieces.
186 const Bitboard SpaceMask[] = {
187 (1ULL << SQ_C2) | (1ULL << SQ_D2) | (1ULL << SQ_E2) | (1ULL << SQ_F2) |
188 (1ULL << SQ_C3) | (1ULL << SQ_D3) | (1ULL << SQ_E3) | (1ULL << SQ_F3) |
189 (1ULL << SQ_C4) | (1ULL << SQ_D4) | (1ULL << SQ_E4) | (1ULL << SQ_F4),
190 (1ULL << SQ_C7) | (1ULL << SQ_D7) | (1ULL << SQ_E7) | (1ULL << SQ_F7) |
191 (1ULL << SQ_C6) | (1ULL << SQ_D6) | (1ULL << SQ_E6) | (1ULL << SQ_F6) |
192 (1ULL << SQ_C5) | (1ULL << SQ_D5) | (1ULL << SQ_E5) | (1ULL << SQ_F5)
195 // King danger constants and variables. The king danger scores are taken
196 // from the KingDangerTable[]. Various little "meta-bonuses" measuring
197 // the strength of the enemy attack are added up into an integer, which
198 // is used as an index to KingDangerTable[].
200 // King safety evaluation is asymmetrical and different for us (root color)
201 // and for our opponent. These values are used to init KingDangerTable.
202 const int KingDangerWeights[] = { 259, 247 };
204 // KingAttackWeights[PieceType] contains king attack weights by piece type
205 const int KingAttackWeights[] = { 0, 0, 2, 2, 3, 5 };
207 // Bonuses for enemy's safe checks
208 const int QueenContactCheckBonus = 6;
209 const int RookContactCheckBonus = 4;
210 const int QueenCheckBonus = 3;
211 const int RookCheckBonus = 2;
212 const int BishopCheckBonus = 1;
213 const int KnightCheckBonus = 1;
215 // InitKingDanger[Square] contains penalties based on the position of the
216 // defending king, indexed by king's square (from white's point of view).
217 const int InitKingDanger[] = {
218 2, 0, 2, 5, 5, 2, 0, 2,
219 2, 2, 4, 8, 8, 4, 2, 2,
220 7, 10, 12, 12, 12, 12, 10, 7,
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,
225 15, 15, 15, 15, 15, 15, 15, 15
228 // KingDangerTable[Color][attackUnits] contains the actual king danger
229 // weighted scores, indexed by color and by a calculated integer number.
230 Score KingDangerTable[COLOR_NB][128];
232 // TracedTerms[Color][PieceType || TracedType] contains a breakdown of the
233 // evaluation terms, used when tracing.
234 Score TracedScores[COLOR_NB][16];
235 std::stringstream TraceStream;
238 PST = 8, IMBALANCE = 9, MOBILITY = 10, THREAT = 11,
239 PASSED = 12, UNSTOPPABLE = 13, SPACE = 14, TOTAL = 15
242 // Function prototypes
244 Value do_evaluate(const Position& pos, Value& margin);
247 void init_eval_info(const Position& pos, EvalInfo& ei);
249 template<Color Us, bool Trace>
250 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility);
252 template<Color Us, bool Trace>
253 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]);
256 Score evaluate_threats(const Position& pos, EvalInfo& ei);
259 int evaluate_space(const Position& pos, EvalInfo& ei);
262 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
264 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
266 Value interpolate(const Score& v, Phase ph, ScaleFactor sf);
267 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
268 double to_cp(Value v);
269 void trace_add(int idx, Score term_w, Score term_b = SCORE_ZERO);
270 void trace_row(const char* name, int idx);
276 /// evaluate() is the main evaluation function. It always computes two
277 /// values, an endgame score and a middle game score, and interpolates
278 /// between them based on the remaining material.
280 Value evaluate(const Position& pos, Value& margin) {
281 return do_evaluate<false>(pos, margin);
285 /// init() computes evaluation weights from the corresponding UCI parameters
286 /// and setup king tables.
290 Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
291 Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
292 Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
294 int KingDanger[] = { KingDangerWeights[0], KingDangerWeights[1] };
296 // If running in analysis mode, make sure we use symmetrical king safety.
297 // We do so by replacing both KingDanger weights by their average.
298 if (Options["UCI_AnalyseMode"])
299 KingDanger[0] = KingDanger[1] = (KingDanger[0] + KingDanger[1]) / 2;
301 const int MaxSlope = 30;
302 const int Peak = 1280;
304 for (int t = 0, i = 1; i < 100; i++)
306 t = std::min(Peak, std::min(int(0.4 * i * i), t + MaxSlope));
308 KingDangerTable[0][i] = apply_weight(make_score(t, 0), make_score(KingDanger[0], 0));
309 KingDangerTable[1][i] = apply_weight(make_score(t, 0), make_score(KingDanger[1], 0));
314 /// trace() is like evaluate() but instead of a value returns a string suitable
315 /// to be print on stdout with the detailed descriptions and values of each
316 /// evaluation term. Used mainly for debugging.
318 std::string trace(const Position& pos) {
323 Search::RootColor = pos.side_to_move();
326 TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
327 memset(TracedScores, 0, 2 * 16 * sizeof(Score));
329 do_evaluate<true>(pos, margin);
331 totals = TraceStream.str();
334 TraceStream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
335 << " | MG EG | MG EG | MG EG \n"
336 << "---------------------+-------------+-------------+---------------\n";
338 trace_row("Material, PST, Tempo", PST);
339 trace_row("Material imbalance", IMBALANCE);
340 trace_row("Pawns", PAWN);
341 trace_row("Knights", KNIGHT);
342 trace_row("Bishops", BISHOP);
343 trace_row("Rooks", ROOK);
344 trace_row("Queens", QUEEN);
345 trace_row("Mobility", MOBILITY);
346 trace_row("King safety", KING);
347 trace_row("Threats", THREAT);
348 trace_row("Passed pawns", PASSED);
349 trace_row("Unstoppable pawns", UNSTOPPABLE);
350 trace_row("Space", SPACE);
352 TraceStream << "---------------------+-------------+-------------+---------------\n";
353 trace_row("Total", TOTAL);
354 TraceStream << totals;
356 return TraceStream.str();
365 Value do_evaluate(const Position& pos, Value& margin) {
367 assert(!pos.checkers());
370 Value margins[COLOR_NB];
371 Score score, mobilityWhite, mobilityBlack;
372 Thread* th = pos.this_thread();
374 // margins[] store the uncertainty estimation of position's evaluation
375 // that typically is used by the search for pruning decisions.
376 margins[WHITE] = margins[BLACK] = VALUE_ZERO;
378 // Initialize score by reading the incrementally updated scores included
379 // in the position object (material + piece square tables) and adding
380 // Tempo bonus. Score is computed from the point of view of white.
381 score = pos.psq_score() + (pos.side_to_move() == WHITE ? Tempo : -Tempo);
383 // Probe the material hash table
384 ei.mi = Material::probe(pos, th->materialTable, th->endgames);
385 score += ei.mi->material_value();
387 // If we have a specialized evaluation function for the current material
388 // configuration, call it and return.
389 if (ei.mi->specialized_eval_exists())
392 return ei.mi->evaluate(pos);
395 // Probe the pawn hash table
396 ei.pi = Pawns::probe(pos, th->pawnsTable);
397 score += ei.pi->pawns_value();
399 // Initialize attack and king safety bitboards
400 init_eval_info<WHITE>(pos, ei);
401 init_eval_info<BLACK>(pos, ei);
403 // Evaluate pieces and mobility
404 score += evaluate_pieces_of_color<WHITE, Trace>(pos, ei, mobilityWhite)
405 - evaluate_pieces_of_color<BLACK, Trace>(pos, ei, mobilityBlack);
407 score += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
409 // Evaluate kings after all other pieces because we need complete attack
410 // information when computing the king safety evaluation.
411 score += evaluate_king<WHITE, Trace>(pos, ei, margins)
412 - evaluate_king<BLACK, Trace>(pos, ei, margins);
414 // Evaluate tactical threats, we need full attack information including king
415 score += evaluate_threats<WHITE>(pos, ei)
416 - evaluate_threats<BLACK>(pos, ei);
418 // Evaluate passed pawns, we need full attack information including king
419 score += evaluate_passed_pawns<WHITE>(pos, ei)
420 - evaluate_passed_pawns<BLACK>(pos, ei);
422 // If one side has only a king, check whether exists any unstoppable passed pawn
423 if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
424 score += evaluate_unstoppable_pawns(pos, ei);
426 // Evaluate space for both sides, only in middle-game.
427 if (ei.mi->space_weight())
429 int s = evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei);
430 score += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]);
433 // Scale winning side if position is more drawish that what it appears
434 ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE)
435 : ei.mi->scale_factor(pos, BLACK);
437 // If we don't already have an unusual scale factor, check for opposite
438 // colored bishop endgames, and use a lower scale for those.
439 if ( ei.mi->game_phase() < PHASE_MIDGAME
440 && pos.opposite_bishops()
441 && sf == SCALE_FACTOR_NORMAL)
443 // Only the two bishops ?
444 if ( pos.non_pawn_material(WHITE) == BishopValueMg
445 && pos.non_pawn_material(BLACK) == BishopValueMg)
447 // Check for KBP vs KB with only a single pawn that is almost
448 // certainly a draw or at least two pawns.
449 bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
450 sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
453 // Endgame with opposite-colored bishops, but also other pieces. Still
454 // a bit drawish, but not as drawish as with only the two bishops.
455 sf = ScaleFactor(50);
458 margin = margins[pos.side_to_move()];
459 Value v = interpolate(score, ei.mi->game_phase(), sf);
461 // In case of tracing add all single evaluation contributions for both white and black
464 trace_add(PST, pos.psq_score());
465 trace_add(IMBALANCE, ei.mi->material_value());
466 trace_add(PAWN, ei.pi->pawns_value());
467 trace_add(MOBILITY, apply_weight(mobilityWhite, Weights[Mobility]), apply_weight(mobilityBlack, Weights[Mobility]));
468 trace_add(THREAT, evaluate_threats<WHITE>(pos, ei), evaluate_threats<BLACK>(pos, ei));
469 trace_add(PASSED, evaluate_passed_pawns<WHITE>(pos, ei), evaluate_passed_pawns<BLACK>(pos, ei));
470 trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns(pos, ei));
471 Score w = make_score(ei.mi->space_weight() * evaluate_space<WHITE>(pos, ei), 0);
472 Score b = make_score(ei.mi->space_weight() * evaluate_space<BLACK>(pos, ei), 0);
473 trace_add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
474 trace_add(TOTAL, score);
475 TraceStream << "\nUncertainty margin: White: " << to_cp(margins[WHITE])
476 << ", Black: " << to_cp(margins[BLACK])
477 << "\nScaling: " << std::noshowpos
478 << std::setw(6) << 100.0 * ei.mi->game_phase() / 128.0 << "% MG, "
479 << std::setw(6) << 100.0 * (1.0 - ei.mi->game_phase() / 128.0) << "% * "
480 << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
481 << "Total evaluation: " << to_cp(v);
484 return pos.side_to_move() == WHITE ? v : -v;
488 // init_eval_info() initializes king bitboards for given color adding
489 // pawn attacks. To be done at the beginning of the evaluation.
492 void init_eval_info(const Position& pos, EvalInfo& ei) {
494 const Color Them = (Us == WHITE ? BLACK : WHITE);
496 Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
497 ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
499 // Init king safety tables only if we are going to use them
500 if ( pos.piece_count(Us, QUEEN)
501 && pos.non_pawn_material(Us) > QueenValueMg + PawnValueMg)
503 ei.kingRing[Them] = (b | (Us == WHITE ? b >> 8 : b << 8));
504 b &= ei.attackedBy[Us][PAWN];
505 ei.kingAttackersCount[Us] = b ? popcount<Max15>(b) / 2 : 0;
506 ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
508 ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0;
512 // evaluate_outposts() evaluates bishop and knight outposts squares
514 template<PieceType Piece, Color Us>
515 Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
517 const Color Them = (Us == WHITE ? BLACK : WHITE);
519 assert (Piece == BISHOP || Piece == KNIGHT);
521 // Initial bonus based on square
522 Value bonus = OutpostBonus[Piece == BISHOP][relative_square(Us, s)];
524 // Increase bonus if supported by pawn, especially if the opponent has
525 // no minor piece which can exchange the outpost piece.
526 if (bonus && (ei.attackedBy[Us][PAWN] & s))
528 if ( !pos.pieces(Them, KNIGHT)
529 && !(same_color_squares(s) & pos.pieces(Them, BISHOP)))
530 bonus += bonus + bonus / 2;
534 return make_score(bonus, bonus);
538 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
540 template<PieceType Piece, Color Us, bool Trace>
541 Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
547 Score score = SCORE_ZERO;
549 const Color Them = (Us == WHITE ? BLACK : WHITE);
550 const Square* pl = pos.piece_list(Us, Piece);
552 ei.attackedBy[Us][Piece] = 0;
554 while ((s = *pl++) != SQ_NONE)
556 // Find attacked squares, including x-ray attacks for bishops and rooks
557 if (Piece == KNIGHT || Piece == QUEEN)
558 b = pos.attacks_from<Piece>(s);
559 else if (Piece == BISHOP)
560 b = attacks_bb<BISHOP>(s, pos.pieces() ^ pos.pieces(Us, QUEEN));
561 else if (Piece == ROOK)
562 b = attacks_bb<ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN));
566 ei.attackedBy[Us][Piece] |= b;
568 if (b & ei.kingRing[Them])
570 ei.kingAttackersCount[Us]++;
571 ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
572 Bitboard bb = (b & ei.attackedBy[Them][KING]);
574 ei.kingAdjacentZoneAttacksCount[Us] += popcount<Max15>(bb);
577 mob = (Piece != QUEEN ? popcount<Max15>(b & mobilityArea)
578 : popcount<Full >(b & mobilityArea));
580 mobility += MobilityBonus[Piece][mob];
582 // Decrease score if we are attacked by an enemy pawn. Remaining part
583 // of threat evaluation must be done later when we have full attack info.
584 if (ei.attackedBy[Them][PAWN] & s)
585 score -= ThreatenedByPawnPenalty[Piece];
587 // Otherwise give a bonus if we are a bishop and can pin a piece or
588 // can give a discovered check through an x-ray attack.
589 else if ( Piece == BISHOP
590 && (PseudoAttacks[Piece][pos.king_square(Them)] & s)
591 && !more_than_one(BetweenBB[s][pos.king_square(Them)] & pos.pieces()))
592 score += BishopPinBonus;
594 // Bishop and knight outposts squares
595 if ( (Piece == BISHOP || Piece == KNIGHT)
596 && !(pos.pieces(Them, PAWN) & attack_span_mask(Us, s)))
597 score += evaluate_outposts<Piece, Us>(pos, ei, s);
599 if ((Piece == ROOK || Piece == QUEEN) && relative_rank(Us, s) >= RANK_5)
601 // Major piece on 7th rank
602 if ( relative_rank(Us, s) == RANK_7
603 && relative_rank(Us, pos.king_square(Them)) == RANK_8)
604 score += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
606 // Major piece attacking pawns on the same rank
607 Bitboard pawns = pos.pieces(Them, PAWN) & rank_bb(s);
609 score += (Piece == ROOK ? RookOnPawnBonus
610 : QueenOnPawnBonus) * popcount<Max15>(pawns);
613 // Special extra evaluation for bishops
614 if (Piece == BISHOP && pos.is_chess960())
616 // An important Chess960 pattern: A cornered bishop blocked by
617 // a friendly pawn diagonally in front of it is a very serious
618 // problem, especially when that pawn is also blocked.
619 if (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1))
621 Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
622 if (pos.piece_on(s + d) == make_piece(Us, PAWN))
624 if (!pos.is_empty(s + d + pawn_push(Us)))
625 score -= 2*TrappedBishopA1H1Penalty;
626 else if (pos.piece_on(s + 2*d) == make_piece(Us, PAWN))
627 score -= TrappedBishopA1H1Penalty;
629 score -= TrappedBishopA1H1Penalty / 2;
634 // Special extra evaluation for rooks
637 // Open and half-open files
639 if (ei.pi->file_is_half_open(Us, f))
641 if (ei.pi->file_is_half_open(Them, f))
642 score += RookOpenFileBonus;
644 score += RookHalfOpenFileBonus;
647 // Penalize rooks which are trapped inside a king. Penalize more if
648 // king has lost right to castle.
649 if (mob > 6 || ei.pi->file_is_half_open(Us, f))
652 ksq = pos.king_square(Us);
654 if ( file_of(ksq) >= FILE_E
655 && file_of(s) > file_of(ksq)
656 && (relative_rank(Us, ksq) == RANK_1 || rank_of(ksq) == rank_of(s)))
658 // Is there a half-open file between the king and the edge of the board?
659 if (!ei.pi->has_open_file_to_right(Us, file_of(ksq)))
660 score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
661 : (TrappedRookPenalty - mob * 16), 0);
663 else if ( file_of(ksq) <= FILE_D
664 && file_of(s) < file_of(ksq)
665 && (relative_rank(Us, ksq) == RANK_1 || rank_of(ksq) == rank_of(s)))
667 // Is there a half-open file between the king and the edge of the board?
668 if (!ei.pi->has_open_file_to_left(Us, file_of(ksq)))
669 score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
670 : (TrappedRookPenalty - mob * 16), 0);
676 TracedScores[Us][Piece] = score;
682 // evaluate_threats<>() assigns bonuses according to the type of attacking piece
683 // and the type of attacked one.
686 Score evaluate_threats(const Position& pos, EvalInfo& ei) {
688 const Color Them = (Us == WHITE ? BLACK : WHITE);
690 Bitboard b, undefendedMinors, weakEnemies;
691 Score score = SCORE_ZERO;
693 // Undefended minors get penalized even if not under attack
694 undefendedMinors = pos.pieces(Them)
695 & (pos.pieces(BISHOP) | pos.pieces(KNIGHT))
696 & ~ei.attackedBy[Them][ALL_PIECES];
698 if (undefendedMinors)
699 score += UndefendedMinorPenalty;
701 // Enemy pieces not defended by a pawn and under our attack
702 weakEnemies = pos.pieces(Them)
703 & ~ei.attackedBy[Them][PAWN]
704 & ei.attackedBy[Us][ALL_PIECES];
709 // Add bonus according to type of attacked enemy piece and to the
710 // type of attacking piece, from knights to queens. Kings are not
711 // considered because are already handled in king evaluation.
712 for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
714 b = ei.attackedBy[Us][pt1] & weakEnemies;
716 for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
717 if (b & pos.pieces(pt2))
718 score += ThreatBonus[pt1][pt2];
724 // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
725 // pieces of a given color.
727 template<Color Us, bool Trace>
728 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) {
730 const Color Them = (Us == WHITE ? BLACK : WHITE);
732 Score score = mobility = SCORE_ZERO;
734 // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
735 const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces(Us));
737 score += evaluate_pieces<KNIGHT, Us, Trace>(pos, ei, mobility, mobilityArea);
738 score += evaluate_pieces<BISHOP, Us, Trace>(pos, ei, mobility, mobilityArea);
739 score += evaluate_pieces<ROOK, Us, Trace>(pos, ei, mobility, mobilityArea);
740 score += evaluate_pieces<QUEEN, Us, Trace>(pos, ei, mobility, mobilityArea);
742 // Sum up all attacked squares
743 ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
744 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
745 | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
750 // evaluate_king<>() assigns bonuses and penalties to a king of a given color
752 template<Color Us, bool Trace>
753 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
755 const Color Them = (Us == WHITE ? BLACK : WHITE);
757 Bitboard undefended, b, b1, b2, safe;
759 const Square ksq = pos.king_square(Us);
761 // King shelter and enemy pawns storm
762 Score score = ei.pi->king_safety<Us>(pos, ksq);
764 // King safety. This is quite complicated, and is almost certainly far
765 // from optimally tuned.
766 if ( ei.kingAttackersCount[Them] >= 2
767 && ei.kingAdjacentZoneAttacksCount[Them])
769 // Find the attacked squares around the king which has no defenders
770 // apart from the king itself
771 undefended = ei.attackedBy[Them][ALL_PIECES] & ei.attackedBy[Us][KING];
772 undefended &= ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
773 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
774 | ei.attackedBy[Us][QUEEN]);
776 // Initialize the 'attackUnits' variable, which is used later on as an
777 // index to the KingDangerTable[] array. The initial value is based on
778 // the number and types of the enemy's attacking pieces, the number of
779 // attacked and undefended squares around our king, the square of the
780 // king, and the quality of the pawn shelter.
781 attackUnits = std::min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
782 + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount<Max15>(undefended))
783 + InitKingDanger[relative_square(Us, ksq)]
784 - mg_value(score) / 32;
786 // Analyse enemy's safe queen contact checks. First find undefended
787 // squares around the king attacked by enemy queen...
788 b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
791 // ...then remove squares not supported by another enemy piece
792 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
793 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
795 attackUnits += QueenContactCheckBonus
797 * (Them == pos.side_to_move() ? 2 : 1);
800 // Analyse enemy's safe rook contact checks. First find undefended
801 // squares around the king attacked by enemy rooks...
802 b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
804 // Consider only squares where the enemy rook gives check
805 b &= PseudoAttacks[ROOK][ksq];
809 // ...then remove squares not supported by another enemy piece
810 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
811 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]);
813 attackUnits += RookContactCheckBonus
815 * (Them == pos.side_to_move() ? 2 : 1);
818 // Analyse enemy's safe distance checks for sliders and knights
819 safe = ~(pos.pieces(Them) | ei.attackedBy[Us][ALL_PIECES]);
821 b1 = pos.attacks_from<ROOK>(ksq) & safe;
822 b2 = pos.attacks_from<BISHOP>(ksq) & safe;
824 // Enemy queen safe checks
825 b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
827 attackUnits += QueenCheckBonus * popcount<Max15>(b);
829 // Enemy rooks safe checks
830 b = b1 & ei.attackedBy[Them][ROOK];
832 attackUnits += RookCheckBonus * popcount<Max15>(b);
834 // Enemy bishops safe checks
835 b = b2 & ei.attackedBy[Them][BISHOP];
837 attackUnits += BishopCheckBonus * popcount<Max15>(b);
839 // Enemy knights safe checks
840 b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
842 attackUnits += KnightCheckBonus * popcount<Max15>(b);
844 // To index KingDangerTable[] attackUnits must be in [0, 99] range
845 attackUnits = std::min(99, std::max(0, attackUnits));
847 // Finally, extract the king danger score from the KingDangerTable[]
848 // array and subtract the score from evaluation. Set also margins[]
849 // value that will be used for pruning because this value can sometimes
850 // be very big, and so capturing a single attacking piece can therefore
851 // result in a score change far bigger than the value of the captured piece.
852 score -= KingDangerTable[Us == Search::RootColor][attackUnits];
853 margins[Us] += mg_value(KingDangerTable[Us == Search::RootColor][attackUnits]);
857 TracedScores[Us][KING] = score;
863 // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
866 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
868 const Color Them = (Us == WHITE ? BLACK : WHITE);
870 Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
871 Score score = SCORE_ZERO;
873 b = ei.pi->passed_pawns(Us);
879 Square s = pop_lsb(&b);
881 assert(pos.pawn_is_passed(Us, s));
883 int r = int(relative_rank(Us, s) - RANK_2);
884 int rr = r * (r - 1);
886 // Base bonus based on rank
887 Value mbonus = Value(20 * rr);
888 Value ebonus = Value(10 * (rr + r + 1));
892 Square blockSq = s + pawn_push(Us);
894 // Adjust bonus based on kings proximity
895 ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 5 * rr);
896 ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 2 * rr);
898 // If blockSq is not the queening square then consider also a second push
899 if (rank_of(blockSq) != (Us == WHITE ? RANK_8 : RANK_1))
900 ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
902 // If the pawn is free to advance, increase bonus
903 if (pos.is_empty(blockSq))
905 squaresToQueen = forward_bb(Us, s);
906 defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES];
908 // If there is an enemy rook or queen attacking the pawn from behind,
909 // add all X-ray attacks by the rook or queen. Otherwise consider only
910 // the squares in the pawn's path attacked or occupied by the enemy.
911 if ( (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN))
912 && (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN) & pos.attacks_from<ROOK>(s)))
913 unsafeSquares = squaresToQueen;
915 unsafeSquares = squaresToQueen & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
917 // If there aren't enemy attacks or pieces along the path to queen give
918 // huge bonus. Even bigger if we protect the pawn's path.
920 ebonus += Value(rr * (squaresToQueen == defendedSquares ? 17 : 15));
922 // OK, there are enemy attacks or pieces (but not pawns). Are those
923 // squares which are attacked by the enemy also attacked by us ?
924 // If yes, big bonus (but smaller than when there are no enemy attacks),
925 // if no, somewhat smaller bonus.
926 ebonus += Value(rr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8));
930 // Increase the bonus if the passed pawn is supported by a friendly pawn
931 // on the same rank and a bit smaller if it's on the previous rank.
932 supportingPawns = pos.pieces(Us, PAWN) & adjacent_files_bb(file_of(s));
933 if (supportingPawns & rank_bb(s))
934 ebonus += Value(r * 20);
936 else if (supportingPawns & rank_bb(s - pawn_push(Us)))
937 ebonus += Value(r * 12);
939 // Rook pawns are a special case: They are sometimes worse, and
940 // sometimes better than other passed pawns. It is difficult to find
941 // good rules for determining whether they are good or bad. For now,
942 // we try the following: Increase the value for rook pawns if the
943 // other side has no pieces apart from a knight, and decrease the
944 // value if the other side has a rook or queen.
945 if (file_of(s) == FILE_A || file_of(s) == FILE_H)
947 if (pos.non_pawn_material(Them) <= KnightValueMg)
948 ebonus += ebonus / 4;
949 else if (pos.pieces(Them, ROOK, QUEEN))
950 ebonus -= ebonus / 4;
952 score += make_score(mbonus, ebonus);
956 // Add the scores to the middle game and endgame eval
957 return apply_weight(score, Weights[PassedPawns]);
961 // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides, this is quite
962 // conservative and returns a winning score only when we are very sure that the pawn is winning.
964 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
966 Bitboard b, b2, blockers, supporters, queeningPath, candidates;
967 Square s, blockSq, queeningSquare;
968 Color c, winnerSide, loserSide;
969 bool pathDefended, opposed;
970 int pliesToGo, movesToGo, oppMovesToGo, sacptg, blockersCount, minKingDist, kingptg, d;
971 int pliesToQueen[] = { 256, 256 };
973 // Step 1. Hunt for unstoppable passed pawns. If we find at least one,
974 // record how many plies are required for promotion.
975 for (c = WHITE; c <= BLACK; c++)
977 // Skip if other side has non-pawn pieces
978 if (pos.non_pawn_material(~c))
981 b = ei.pi->passed_pawns(c);
986 queeningSquare = relative_square(c, file_of(s) | RANK_8);
987 queeningPath = forward_bb(c, s);
989 // Compute plies to queening and check direct advancement
990 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(c, s) == RANK_2);
991 oppMovesToGo = square_distance(pos.king_square(~c), queeningSquare) - int(c != pos.side_to_move());
992 pathDefended = ((ei.attackedBy[c][ALL_PIECES] & queeningPath) == queeningPath);
994 if (movesToGo >= oppMovesToGo && !pathDefended)
997 // Opponent king cannot block because path is defended and position
998 // is not in check. So only friendly pieces can be blockers.
999 assert(!pos.checkers());
1000 assert((queeningPath & pos.pieces()) == (queeningPath & pos.pieces(c)));
1002 // Add moves needed to free the path from friendly pieces and retest condition
1003 movesToGo += popcount<Max15>(queeningPath & pos.pieces(c));
1005 if (movesToGo >= oppMovesToGo && !pathDefended)
1008 pliesToGo = 2 * movesToGo - int(c == pos.side_to_move());
1009 pliesToQueen[c] = std::min(pliesToQueen[c], pliesToGo);
1013 // Step 2. If either side cannot promote at least three plies before the other side then situation
1014 // becomes too complex and we give up. Otherwise we determine the possibly "winning side"
1015 if (abs(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3)
1018 winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK);
1019 loserSide = ~winnerSide;
1021 // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
1022 b = candidates = pos.pieces(loserSide, PAWN);
1028 // Compute plies from queening
1029 queeningSquare = relative_square(loserSide, file_of(s) | RANK_8);
1030 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
1031 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
1033 // Check if (without even considering any obstacles) we're too far away or doubled
1034 if ( pliesToQueen[winnerSide] + 3 <= pliesToGo
1035 || (forward_bb(loserSide, s) & pos.pieces(loserSide, PAWN)))
1039 // If any candidate is already a passed pawn it _may_ promote in time. We give up.
1040 if (candidates & ei.pi->passed_pawns(loserSide))
1043 // Step 4. Check new passed pawn creation through king capturing and pawn sacrifices
1049 sacptg = blockersCount = 0;
1050 minKingDist = kingptg = 256;
1052 // Compute plies from queening
1053 queeningSquare = relative_square(loserSide, file_of(s) | RANK_8);
1054 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
1055 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
1057 // Generate list of blocking pawns and supporters
1058 supporters = adjacent_files_bb(file_of(s)) & candidates;
1059 opposed = forward_bb(loserSide, s) & pos.pieces(winnerSide, PAWN);
1060 blockers = passed_pawn_mask(loserSide, s) & pos.pieces(winnerSide, PAWN);
1064 // How many plies does it take to remove all the blocking pawns?
1067 blockSq = pop_lsb(&blockers);
1070 // Check pawns that can give support to overcome obstacle, for instance
1071 // black pawns: a4, b4 white: b2 then pawn in b4 is giving support.
1074 b2 = supporters & in_front_bb(winnerSide, blockSq + pawn_push(winnerSide));
1076 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1078 d = square_distance(blockSq, pop_lsb(&b2)) - 2;
1079 movesToGo = std::min(movesToGo, d);
1083 // Check pawns that can be sacrificed against the blocking pawn
1084 b2 = attack_span_mask(winnerSide, blockSq) & candidates & ~(1ULL << s);
1086 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1088 d = square_distance(blockSq, pop_lsb(&b2)) - 2;
1089 movesToGo = std::min(movesToGo, d);
1092 // If obstacle can be destroyed with an immediate pawn exchange / sacrifice,
1093 // it's not a real obstacle and we have nothing to add to pliesToGo.
1097 // Plies needed to sacrifice against all the blocking pawns
1098 sacptg += movesToGo * 2;
1101 // Plies needed for the king to capture all the blocking pawns
1102 d = square_distance(pos.king_square(loserSide), blockSq);
1103 minKingDist = std::min(minKingDist, d);
1104 kingptg = (minKingDist + blockersCount) * 2;
1107 // Check if pawn sacrifice plan _may_ save the day
1108 if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg)
1111 // Check if king capture plan _may_ save the day (contains some false positives)
1112 if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg)
1116 // Winning pawn is unstoppable and will promote as first, return big score
1117 Score score = make_score(0, (Value) 1280 - 32 * pliesToQueen[winnerSide]);
1118 return winnerSide == WHITE ? score : -score;
1122 // evaluate_space() computes the space evaluation for a given side. The
1123 // space evaluation is a simple bonus based on the number of safe squares
1124 // available for minor pieces on the central four files on ranks 2--4. Safe
1125 // squares one, two or three squares behind a friendly pawn are counted
1126 // twice. Finally, the space bonus is scaled by a weight taken from the
1127 // material hash table. The aim is to improve play on game opening.
1129 int evaluate_space(const Position& pos, EvalInfo& ei) {
1131 const Color Them = (Us == WHITE ? BLACK : WHITE);
1133 // Find the safe squares for our pieces inside the area defined by
1134 // SpaceMask[]. A square is unsafe if it is attacked by an enemy
1135 // pawn, or if it is undefended and attacked by an enemy piece.
1136 Bitboard safe = SpaceMask[Us]
1137 & ~pos.pieces(Us, PAWN)
1138 & ~ei.attackedBy[Them][PAWN]
1139 & (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
1141 // Find all squares which are at most three squares behind some friendly pawn
1142 Bitboard behind = pos.pieces(Us, PAWN);
1143 behind |= (Us == WHITE ? behind >> 8 : behind << 8);
1144 behind |= (Us == WHITE ? behind >> 16 : behind << 16);
1146 // Since SpaceMask[Us] is fully on our half of the board
1147 assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);
1149 // Count safe + (behind & safe) with a single popcount
1150 return popcount<Full>((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
1154 // interpolate() interpolates between a middle game and an endgame score,
1155 // based on game phase. It also scales the return value by a ScaleFactor array.
1157 Value interpolate(const Score& v, Phase ph, ScaleFactor sf) {
1159 assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
1160 assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
1161 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1163 int ev = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
1164 int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128;
1165 return Value((result + GrainSize / 2) & ~(GrainSize - 1));
1169 // weight_option() computes the value of an evaluation weight, by combining
1170 // two UCI-configurable weights (midgame and endgame) with an internal weight.
1172 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
1174 // Scale option value from 100 to 256
1175 int mg = Options[mgOpt] * 256 / 100;
1176 int eg = Options[egOpt] * 256 / 100;
1178 return apply_weight(make_score(mg, eg), internalWeight);
1182 // A couple of little helpers used by tracing code, to_cp() converts a value to
1183 // a double in centipawns scale, trace_add() stores white and black scores.
1185 double to_cp(Value v) { return double(v) / double(PawnValueMg); }
1187 void trace_add(int idx, Score wScore, Score bScore) {
1189 TracedScores[WHITE][idx] = wScore;
1190 TracedScores[BLACK][idx] = bScore;
1194 // trace_row() is an helper function used by tracing code to register the
1195 // values of a single evaluation term.
1197 void trace_row(const char* name, int idx) {
1199 Score wScore = TracedScores[WHITE][idx];
1200 Score bScore = TracedScores[BLACK][idx];
1203 case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL:
1204 TraceStream << std::setw(20) << name << " | --- --- | --- --- | "
1205 << std::setw(6) << to_cp(mg_value(wScore)) << " "
1206 << std::setw(6) << to_cp(eg_value(wScore)) << " \n";
1209 TraceStream << std::setw(20) << name << " | " << std::noshowpos
1210 << std::setw(5) << to_cp(mg_value(wScore)) << " "
1211 << std::setw(5) << to_cp(eg_value(wScore)) << " | "
1212 << std::setw(5) << to_cp(mg_value(bScore)) << " "
1213 << std::setw(5) << to_cp(eg_value(bScore)) << " | "
1215 << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " "
1216 << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n";