2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2012 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/>.
31 #include "ucioption.h"
35 // Struct EvalInfo contains various information computed and collected
36 // by the evaluation functions.
39 // Pointers to material and pawn hash table entries
43 // attackedBy[color][piece type] is a bitboard representing all squares
44 // attacked by a given color and piece type, attackedBy[color][0] contains
45 // all squares attacked by the given color.
46 Bitboard attackedBy[2][8];
48 // kingRing[color] is the zone around the king which is considered
49 // by the king safety evaluation. This consists of the squares directly
50 // adjacent to the king, and the three (or two, for a king on an edge file)
51 // squares two ranks in front of the king. For instance, if black's king
52 // is on g8, kingRing[BLACK] is a bitboard containing the squares f8, h8,
53 // f7, g7, h7, f6, g6 and h6.
56 // kingAttackersCount[color] is the number of pieces of the given color
57 // which attack a square in the kingRing of the enemy king.
58 int kingAttackersCount[2];
60 // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
61 // given color which attack a square in the kingRing of the enemy king. The
62 // weights of the individual piece types are given by the variables
63 // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
64 // KnightAttackWeight in evaluate.cpp
65 int kingAttackersWeight[2];
67 // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
68 // directly adjacent to the king of the given color. Pieces which attack
69 // more than one square are counted multiple times. For instance, if black's
70 // king is on g8 and there's a white knight on g5, this knight adds
71 // 2 to kingAdjacentZoneAttacksCount[BLACK].
72 int kingAdjacentZoneAttacksCount[2];
75 // Evaluation grain size, must be a power of 2
76 const int GrainSize = 8;
78 // Evaluation weights, initialized from UCI options
79 enum { Mobility, PassedPawns, Space, KingDangerUs, KingDangerThem };
83 #define S(mg, eg) make_score(mg, eg)
85 // Internal evaluation weights. These are applied on top of the evaluation
86 // weights read from UCI parameters. The purpose is to be able to change
87 // the evaluation weights while keeping the default values of the UCI
88 // parameters at 100, which looks prettier.
90 // Values modified by Joona Kiiski
91 const Score WeightsInternal[] = {
92 S(252, 344), S(216, 266), S(46, 0), S(247, 0), S(259, 0)
95 // MobilityBonus[PieceType][attacked] contains mobility bonuses for middle and
96 // end game, indexed by piece type and number of attacked squares not occupied
97 // by friendly pieces.
98 const Score MobilityBonus[][32] = {
100 { S(-38,-33), S(-25,-23), S(-12,-13), S( 0, -3), S(12, 7), S(25, 17), // Knights
101 S( 31, 22), S( 38, 27), S( 38, 27) },
102 { S(-25,-30), S(-11,-16), S( 3, -2), S(17, 12), S(31, 26), S(45, 40), // Bishops
103 S( 57, 52), S( 65, 60), S( 71, 65), S(74, 69), S(76, 71), S(78, 73),
104 S( 79, 74), S( 80, 75), S( 81, 76), S(81, 76) },
105 { S(-20,-36), S(-14,-19), S( -8, -3), S(-2, 13), S( 4, 29), S(10, 46), // Rooks
106 S( 14, 62), S( 19, 79), S( 23, 95), S(26,106), S(27,111), S(28,114),
107 S( 29,116), S( 30,117), S( 31,118), S(32,118) },
108 { S(-10,-18), S( -8,-13), S( -6, -7), S(-3, -2), S(-1, 3), S( 1, 8), // Queens
109 S( 3, 13), S( 5, 19), S( 8, 23), S(10, 27), S(12, 32), S(15, 34),
110 S( 16, 35), S( 17, 35), S( 18, 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), S( 20, 35), S(20, 35), S(20, 35), S(20, 35),
113 S( 20, 35), S( 20, 35) }
116 // OutpostBonus[PieceType][Square] contains outpost bonuses of knights and
117 // bishops, indexed by piece type and square (from white's point of view).
118 const Value OutpostBonus[][64] = {
121 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Knights
122 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
123 V(0), V(0), V(4), V(8), V(8), V(4), V(0), V(0),
124 V(0), V(4),V(17),V(26),V(26),V(17), V(4), V(0),
125 V(0), V(8),V(26),V(35),V(35),V(26), V(8), V(0),
126 V(0), V(4),V(17),V(17),V(17),V(17), V(4), V(0) },
128 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Bishops
129 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
130 V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0),
131 V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0),
132 V(0),V(10),V(21),V(21),V(21),V(21),V(10), V(0),
133 V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0) }
136 // ThreatBonus[attacking][attacked] contains threat bonuses according to
137 // which piece type attacks which one.
138 const Score ThreatBonus[][8] = {
140 { S(0, 0), S( 7, 39), S( 0, 0), S(24, 49), S(41,100), S(41,100) }, // KNIGHT
141 { S(0, 0), S( 7, 39), S(24, 49), S( 0, 0), S(41,100), S(41,100) }, // BISHOP
142 { S(0, 0), S(-1, 29), S(15, 49), S(15, 49), S( 0, 0), S(24, 49) }, // ROOK
143 { S(0, 0), S(15, 39), S(15, 39), S(15, 39), S(15, 39), S( 0, 0) } // QUEEN
146 // ThreatenedByPawnPenalty[PieceType] contains a penalty according to which
147 // piece type is attacked by an enemy pawn.
148 const Score ThreatenedByPawnPenalty[] = {
149 S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
154 // Rooks and queens on the 7th rank (modified by Joona Kiiski)
155 const Score RookOn7thBonus = make_score(47, 98);
156 const Score QueenOn7thBonus = make_score(27, 54);
158 // Rooks on open files (modified by Joona Kiiski)
159 const Score RookOpenFileBonus = make_score(43, 43);
160 const Score RookHalfOpenFileBonus = make_score(19, 19);
162 // Penalty for rooks trapped inside a friendly king which has lost the
164 const Value TrappedRookPenalty = Value(180);
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(100, 100);
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[2][128];
217 // TracedTerms[Color][PieceType || TracedType] contains a breakdown of the
218 // evaluation terms, used when tracing.
219 Score TracedScores[2][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 inline Score apply_weight(Score v, Score weight);
252 Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf);
253 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
255 double to_cp(Value v);
256 void trace_add(int idx, Score term_w, Score term_b = SCORE_ZERO);
260 /// evaluate() is the main evaluation function. It always computes two
261 /// values, an endgame score and a middle game score, and interpolates
262 /// between them based on the remaining material.
263 Value evaluate(const Position& pos, Value& margin) { return do_evaluate<false>(pos, margin); }
268 Value do_evaluate(const Position& pos, Value& margin) {
272 Score score, mobilityWhite, mobilityBlack;
274 assert(pos.thread() >= 0 && pos.thread() < MAX_THREADS);
275 assert(!pos.in_check());
277 // Initialize score by reading the incrementally updated scores included
278 // in the position object (material + piece square tables).
281 // margins[] store the uncertainty estimation of position's evaluation
282 // that typically is used by the search for pruning decisions.
283 margins[WHITE] = margins[BLACK] = VALUE_ZERO;
285 // Probe the material hash table
286 ei.mi = Threads[pos.thread()].materialTable.material_info(pos);
287 score += ei.mi->material_value();
289 // If we have a specialized evaluation function for the current material
290 // configuration, call it and return.
291 if (ei.mi->specialized_eval_exists())
294 return ei.mi->evaluate(pos);
297 // Probe the pawn hash table
298 ei.pi = Threads[pos.thread()].pawnTable.pawn_info(pos);
299 score += ei.pi->pawns_value();
301 // Initialize attack and king safety bitboards
302 init_eval_info<WHITE>(pos, ei);
303 init_eval_info<BLACK>(pos, ei);
305 // Evaluate pieces and mobility
306 score += evaluate_pieces_of_color<WHITE, Trace>(pos, ei, mobilityWhite)
307 - evaluate_pieces_of_color<BLACK, Trace>(pos, ei, mobilityBlack);
309 score += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
311 // Evaluate kings after all other pieces because we need complete attack
312 // information when computing the king safety evaluation.
313 score += evaluate_king<WHITE, Trace>(pos, ei, margins)
314 - evaluate_king<BLACK, Trace>(pos, ei, margins);
316 // Evaluate tactical threats, we need full attack information including king
317 score += evaluate_threats<WHITE>(pos, ei)
318 - evaluate_threats<BLACK>(pos, ei);
320 // Evaluate passed pawns, we need full attack information including king
321 score += evaluate_passed_pawns<WHITE>(pos, ei)
322 - evaluate_passed_pawns<BLACK>(pos, ei);
324 // If one side has only a king, check whether exists any unstoppable passed pawn
325 if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
326 score += evaluate_unstoppable_pawns(pos, ei);
328 // Evaluate space for both sides, only in middle-game.
329 if (ei.mi->space_weight())
331 int s = evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei);
332 score += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]);
335 // Scale winning side if position is more drawish that what it appears
336 ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE)
337 : ei.mi->scale_factor(pos, BLACK);
339 // If we don't already have an unusual scale factor, check for opposite
340 // colored bishop endgames, and use a lower scale for those.
341 if ( ei.mi->game_phase() < PHASE_MIDGAME
342 && pos.opposite_colored_bishops()
343 && sf == SCALE_FACTOR_NORMAL)
345 // Only the two bishops ?
346 if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
347 && pos.non_pawn_material(BLACK) == BishopValueMidgame)
349 // Check for KBP vs KB with only a single pawn that is almost
350 // certainly a draw or at least two pawns.
351 bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
352 sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
355 // Endgame with opposite-colored bishops, but also other pieces. Still
356 // a bit drawish, but not as drawish as with only the two bishops.
357 sf = ScaleFactor(50);
360 // Interpolate between the middle game and the endgame score
361 margin = margins[pos.side_to_move()];
362 Value v = scale_by_game_phase(score, ei.mi->game_phase(), sf);
364 // In case of tracing add all single evaluation contributions for both white and black
367 trace_add(PST, pos.value());
368 trace_add(IMBALANCE, ei.mi->material_value());
369 trace_add(PAWN, ei.pi->pawns_value());
370 trace_add(MOBILITY, apply_weight(mobilityWhite, Weights[Mobility]), apply_weight(mobilityBlack, Weights[Mobility]));
371 trace_add(THREAT, evaluate_threats<WHITE>(pos, ei), evaluate_threats<BLACK>(pos, ei));
372 trace_add(PASSED, evaluate_passed_pawns<WHITE>(pos, ei), evaluate_passed_pawns<BLACK>(pos, ei));
373 trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns(pos, ei));
374 Score w = make_score(ei.mi->space_weight() * evaluate_space<WHITE>(pos, ei), 0);
375 Score b = make_score(ei.mi->space_weight() * evaluate_space<BLACK>(pos, ei), 0);
376 trace_add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
377 trace_add(TOTAL, score);
378 TraceStream << "\nUncertainty margin: White: " << to_cp(margins[WHITE])
379 << ", Black: " << to_cp(margins[BLACK])
380 << "\nScaling: " << std::noshowpos
381 << std::setw(6) << 100.0 * ei.mi->game_phase() / 128.0 << "% MG, "
382 << std::setw(6) << 100.0 * (1.0 - ei.mi->game_phase() / 128.0) << "% * "
383 << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
384 << "Total evaluation: " << to_cp(v);
387 return pos.side_to_move() == WHITE ? v : -v;
393 /// read_weights() reads evaluation weights from the corresponding UCI parameters
395 void read_evaluation_uci_options(Color us) {
397 // King safety is asymmetrical. Our king danger level is weighted by
398 // "Cowardice" UCI parameter, instead the opponent one by "Aggressiveness".
399 const int kingDangerUs = (us == WHITE ? KingDangerUs : KingDangerThem);
400 const int kingDangerThem = (us == WHITE ? KingDangerThem : KingDangerUs);
402 Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
403 Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
404 Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
405 Weights[kingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
406 Weights[kingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
408 // If running in analysis mode, make sure we use symmetrical king safety. We do this
409 // by replacing both Weights[kingDangerUs] and Weights[kingDangerThem] by their average.
410 if (Options["UCI_AnalyseMode"])
411 Weights[kingDangerUs] = Weights[kingDangerThem] = (Weights[kingDangerUs] + Weights[kingDangerThem]) / 2;
419 // init_eval_info() initializes king bitboards for given color adding
420 // pawn attacks. To be done at the beginning of the evaluation.
423 void init_eval_info(const Position& pos, EvalInfo& ei) {
425 const Color Them = (Us == WHITE ? BLACK : WHITE);
427 Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
428 ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
430 // Init king safety tables only if we are going to use them
431 if ( pos.piece_count(Us, QUEEN)
432 && pos.non_pawn_material(Us) >= QueenValueMidgame + RookValueMidgame)
434 ei.kingRing[Them] = (b | (Us == WHITE ? b >> 8 : b << 8));
435 b &= ei.attackedBy[Us][PAWN];
436 ei.kingAttackersCount[Us] = b ? popcount<Max15>(b) / 2 : 0;
437 ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
439 ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0;
443 // evaluate_outposts() evaluates bishop and knight outposts squares
445 template<PieceType Piece, Color Us>
446 Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
448 const Color Them = (Us == WHITE ? BLACK : WHITE);
450 assert (Piece == BISHOP || Piece == KNIGHT);
452 // Initial bonus based on square
453 Value bonus = OutpostBonus[Piece == BISHOP][relative_square(Us, s)];
455 // Increase bonus if supported by pawn, especially if the opponent has
456 // no minor piece which can exchange the outpost piece.
457 if (bonus && bit_is_set(ei.attackedBy[Us][PAWN], s))
459 if ( !pos.pieces(KNIGHT, Them)
460 && !(same_color_squares(s) & pos.pieces(BISHOP, Them)))
461 bonus += bonus + bonus / 2;
465 return make_score(bonus, bonus);
469 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
471 template<PieceType Piece, Color Us, bool Trace>
472 Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
478 Score score = SCORE_ZERO;
480 const Color Them = (Us == WHITE ? BLACK : WHITE);
481 const Square* pl = pos.piece_list(Us, Piece);
483 ei.attackedBy[Us][Piece] = 0;
485 while ((s = *pl++) != SQ_NONE)
487 // Find attacked squares, including x-ray attacks for bishops and rooks
488 if (Piece == KNIGHT || Piece == QUEEN)
489 b = pos.attacks_from<Piece>(s);
490 else if (Piece == BISHOP)
491 b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
492 else if (Piece == ROOK)
493 b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
497 // Update attack info
498 ei.attackedBy[Us][Piece] |= b;
501 if (b & ei.kingRing[Them])
503 ei.kingAttackersCount[Us]++;
504 ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
505 Bitboard bb = (b & ei.attackedBy[Them][KING]);
507 ei.kingAdjacentZoneAttacksCount[Us] += popcount<Max15>(bb);
511 mob = (Piece != QUEEN ? popcount<Max15>(b & mobilityArea)
512 : popcount<Full >(b & mobilityArea));
514 mobility += MobilityBonus[Piece][mob];
516 // Decrease score if we are attacked by an enemy pawn. Remaining part
517 // of threat evaluation must be done later when we have full attack info.
518 if (bit_is_set(ei.attackedBy[Them][PAWN], s))
519 score -= ThreatenedByPawnPenalty[Piece];
521 // Bishop and knight outposts squares
522 if ( (Piece == BISHOP || Piece == KNIGHT)
523 && !(pos.pieces(PAWN, Them) & attack_span_mask(Us, s)))
524 score += evaluate_outposts<Piece, Us>(pos, ei, s);
526 // Queen or rook on 7th rank
527 if ( (Piece == ROOK || Piece == QUEEN)
528 && relative_rank(Us, s) == RANK_7
529 && relative_rank(Us, pos.king_square(Them)) == RANK_8)
531 score += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
534 // Special extra evaluation for bishops
535 if (Piece == BISHOP && pos.is_chess960())
537 // An important Chess960 pattern: A cornered bishop blocked by
538 // a friendly pawn diagonally in front of it is a very serious
539 // problem, especially when that pawn is also blocked.
540 if (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1))
542 Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
543 if (pos.piece_on(s + d) == make_piece(Us, PAWN))
545 if (!pos.square_is_empty(s + d + pawn_push(Us)))
546 score -= 2*TrappedBishopA1H1Penalty;
547 else if (pos.piece_on(s + 2*d) == make_piece(Us, PAWN))
548 score -= TrappedBishopA1H1Penalty;
550 score -= TrappedBishopA1H1Penalty / 2;
555 // Special extra evaluation for rooks
558 // Open and half-open files
560 if (ei.pi->file_is_half_open(Us, f))
562 if (ei.pi->file_is_half_open(Them, f))
563 score += RookOpenFileBonus;
565 score += RookHalfOpenFileBonus;
568 // Penalize rooks which are trapped inside a king. Penalize more if
569 // king has lost right to castle.
570 if (mob > 6 || ei.pi->file_is_half_open(Us, f))
573 ksq = pos.king_square(Us);
575 if ( file_of(ksq) >= FILE_E
576 && file_of(s) > file_of(ksq)
577 && (relative_rank(Us, ksq) == RANK_1 || rank_of(ksq) == rank_of(s)))
579 // Is there a half-open file between the king and the edge of the board?
580 if (!ei.pi->has_open_file_to_right(Us, file_of(ksq)))
581 score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
582 : (TrappedRookPenalty - mob * 16), 0);
584 else if ( file_of(ksq) <= FILE_D
585 && file_of(s) < file_of(ksq)
586 && (relative_rank(Us, ksq) == RANK_1 || rank_of(ksq) == rank_of(s)))
588 // Is there a half-open file between the king and the edge of the board?
589 if (!ei.pi->has_open_file_to_left(Us, file_of(ksq)))
590 score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
591 : (TrappedRookPenalty - mob * 16), 0);
597 TracedScores[Us][Piece] = score;
603 // evaluate_threats<>() assigns bonuses according to the type of attacking piece
604 // and the type of attacked one.
607 Score evaluate_threats(const Position& pos, EvalInfo& ei) {
609 const Color Them = (Us == WHITE ? BLACK : WHITE);
612 Score score = SCORE_ZERO;
614 // Enemy pieces not defended by a pawn and under our attack
615 Bitboard weakEnemies = pos.pieces(Them)
616 & ~ei.attackedBy[Them][PAWN]
617 & ei.attackedBy[Us][0];
621 // Add bonus according to type of attacked enemy piece and to the
622 // type of attacking piece, from knights to queens. Kings are not
623 // considered because are already handled in king evaluation.
624 for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
626 b = ei.attackedBy[Us][pt1] & weakEnemies;
628 for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
629 if (b & pos.pieces(pt2))
630 score += ThreatBonus[pt1][pt2];
636 // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
637 // pieces of a given color.
639 template<Color Us, bool Trace>
640 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) {
642 const Color Them = (Us == WHITE ? BLACK : WHITE);
644 Score score = mobility = SCORE_ZERO;
646 // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
647 const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces(Us));
649 score += evaluate_pieces<KNIGHT, Us, Trace>(pos, ei, mobility, mobilityArea);
650 score += evaluate_pieces<BISHOP, Us, Trace>(pos, ei, mobility, mobilityArea);
651 score += evaluate_pieces<ROOK, Us, Trace>(pos, ei, mobility, mobilityArea);
652 score += evaluate_pieces<QUEEN, Us, Trace>(pos, ei, mobility, mobilityArea);
654 // Sum up all attacked squares
655 ei.attackedBy[Us][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
656 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
657 | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
662 // evaluate_king<>() assigns bonuses and penalties to a king of a given color
664 template<Color Us, bool Trace>
665 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
667 const Color Them = (Us == WHITE ? BLACK : WHITE);
669 Bitboard undefended, b, b1, b2, safe;
671 const Square ksq = pos.king_square(Us);
674 Score score = ei.pi->king_shelter<Us>(pos, ksq);
676 // King safety. This is quite complicated, and is almost certainly far
677 // from optimally tuned.
678 if ( ei.kingAttackersCount[Them] >= 2
679 && ei.kingAdjacentZoneAttacksCount[Them])
681 // Find the attacked squares around the king which has no defenders
682 // apart from the king itself
683 undefended = ei.attackedBy[Them][0] & ei.attackedBy[Us][KING];
684 undefended &= ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
685 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
686 | ei.attackedBy[Us][QUEEN]);
688 // Initialize the 'attackUnits' variable, which is used later on as an
689 // index to the KingDangerTable[] array. The initial value is based on
690 // the number and types of the enemy's attacking pieces, the number of
691 // attacked and undefended squares around our king, the square of the
692 // king, and the quality of the pawn shelter.
693 attackUnits = std::min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
694 + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount<Max15>(undefended))
695 + InitKingDanger[relative_square(Us, ksq)]
696 - mg_value(ei.pi->king_shelter<Us>(pos, ksq)) / 32;
698 // Analyse enemy's safe queen contact checks. First find undefended
699 // squares around the king attacked by enemy queen...
700 b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces(Them);
703 // ...then remove squares not supported by another enemy piece
704 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
705 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
707 attackUnits += QueenContactCheckBonus
709 * (Them == pos.side_to_move() ? 2 : 1);
712 // Analyse enemy's safe rook contact checks. First find undefended
713 // squares around the king attacked by enemy rooks...
714 b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces(Them);
716 // Consider only squares where the enemy rook gives check
717 b &= PseudoAttacks[ROOK][ksq];
721 // ...then remove squares not supported by another enemy piece
722 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
723 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]);
725 attackUnits += RookContactCheckBonus
727 * (Them == pos.side_to_move() ? 2 : 1);
730 // Analyse enemy's safe distance checks for sliders and knights
731 safe = ~(pos.pieces(Them) | ei.attackedBy[Us][0]);
733 b1 = pos.attacks_from<ROOK>(ksq) & safe;
734 b2 = pos.attacks_from<BISHOP>(ksq) & safe;
736 // Enemy queen safe checks
737 b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
739 attackUnits += QueenCheckBonus * popcount<Max15>(b);
741 // Enemy rooks safe checks
742 b = b1 & ei.attackedBy[Them][ROOK];
744 attackUnits += RookCheckBonus * popcount<Max15>(b);
746 // Enemy bishops safe checks
747 b = b2 & ei.attackedBy[Them][BISHOP];
749 attackUnits += BishopCheckBonus * popcount<Max15>(b);
751 // Enemy knights safe checks
752 b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
754 attackUnits += KnightCheckBonus * popcount<Max15>(b);
756 // To index KingDangerTable[] attackUnits must be in [0, 99] range
757 attackUnits = std::min(99, std::max(0, attackUnits));
759 // Finally, extract the king danger score from the KingDangerTable[]
760 // array and subtract the score from evaluation. Set also margins[]
761 // value that will be used for pruning because this value can sometimes
762 // be very big, and so capturing a single attacking piece can therefore
763 // result in a score change far bigger than the value of the captured piece.
764 score -= KingDangerTable[Us][attackUnits];
765 margins[Us] += mg_value(KingDangerTable[Us][attackUnits]);
769 TracedScores[Us][KING] = score;
775 // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
778 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
780 const Color Them = (Us == WHITE ? BLACK : WHITE);
782 Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
783 Score score = SCORE_ZERO;
785 b = ei.pi->passed_pawns(Us);
791 Square s = pop_1st_bit(&b);
793 assert(pos.pawn_is_passed(Us, s));
795 int r = int(relative_rank(Us, s) - RANK_2);
796 int rr = r * (r - 1);
798 // Base bonus based on rank
799 Value mbonus = Value(20 * rr);
800 Value ebonus = Value(10 * (rr + r + 1));
804 Square blockSq = s + pawn_push(Us);
806 // Adjust bonus based on kings proximity
807 ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 5 * rr);
808 ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 2 * rr);
810 // If blockSq is not the queening square then consider also a second push
811 if (rank_of(blockSq) != (Us == WHITE ? RANK_8 : RANK_1))
812 ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
814 // If the pawn is free to advance, increase bonus
815 if (pos.square_is_empty(blockSq))
817 squaresToQueen = squares_in_front_of(Us, s);
818 defendedSquares = squaresToQueen & ei.attackedBy[Us][0];
820 // If there is an enemy rook or queen attacking the pawn from behind,
821 // add all X-ray attacks by the rook or queen. Otherwise consider only
822 // the squares in the pawn's path attacked or occupied by the enemy.
823 if ( (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them))
824 && (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from<ROOK>(s)))
825 unsafeSquares = squaresToQueen;
827 unsafeSquares = squaresToQueen & (ei.attackedBy[Them][0] | pos.pieces(Them));
829 // If there aren't enemy attacks or pieces along the path to queen give
830 // huge bonus. Even bigger if we protect the pawn's path.
832 ebonus += Value(rr * (squaresToQueen == defendedSquares ? 17 : 15));
834 // OK, there are enemy attacks or pieces (but not pawns). Are those
835 // squares which are attacked by the enemy also attacked by us ?
836 // If yes, big bonus (but smaller than when there are no enemy attacks),
837 // if no, somewhat smaller bonus.
838 ebonus += Value(rr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8));
842 // Increase the bonus if the passed pawn is supported by a friendly pawn
843 // on the same rank and a bit smaller if it's on the previous rank.
844 supportingPawns = pos.pieces(PAWN, Us) & adjacent_files_bb(file_of(s));
845 if (supportingPawns & rank_bb(s))
846 ebonus += Value(r * 20);
848 else if (supportingPawns & rank_bb(s - pawn_push(Us)))
849 ebonus += Value(r * 12);
851 // Rook pawns are a special case: They are sometimes worse, and
852 // sometimes better than other passed pawns. It is difficult to find
853 // good rules for determining whether they are good or bad. For now,
854 // we try the following: Increase the value for rook pawns if the
855 // other side has no pieces apart from a knight, and decrease the
856 // value if the other side has a rook or queen.
857 if (file_of(s) == FILE_A || file_of(s) == FILE_H)
859 if (pos.non_pawn_material(Them) <= KnightValueMidgame)
860 ebonus += ebonus / 4;
861 else if (pos.pieces(ROOK, QUEEN, Them))
862 ebonus -= ebonus / 4;
864 score += make_score(mbonus, ebonus);
868 // Add the scores to the middle game and endgame eval
869 return apply_weight(score, Weights[PassedPawns]);
873 // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides, this is quite
874 // conservative and returns a winning score only when we are very sure that the pawn is winning.
876 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
878 Bitboard b, b2, blockers, supporters, queeningPath, candidates;
879 Square s, blockSq, queeningSquare;
880 Color c, winnerSide, loserSide;
881 bool pathDefended, opposed;
882 int pliesToGo, movesToGo, oppMovesToGo, sacptg, blockersCount, minKingDist, kingptg, d;
883 int pliesToQueen[] = { 256, 256 };
885 // Step 1. Hunt for unstoppable passed pawns. If we find at least one,
886 // record how many plies are required for promotion.
887 for (c = WHITE; c <= BLACK; c++)
889 // Skip if other side has non-pawn pieces
890 if (pos.non_pawn_material(~c))
893 b = ei.pi->passed_pawns(c);
898 queeningSquare = relative_square(c, make_square(file_of(s), RANK_8));
899 queeningPath = squares_in_front_of(c, s);
901 // Compute plies to queening and check direct advancement
902 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(c, s) == RANK_2);
903 oppMovesToGo = square_distance(pos.king_square(~c), queeningSquare) - int(c != pos.side_to_move());
904 pathDefended = ((ei.attackedBy[c][0] & queeningPath) == queeningPath);
906 if (movesToGo >= oppMovesToGo && !pathDefended)
909 // Opponent king cannot block because path is defended and position
910 // is not in check. So only friendly pieces can be blockers.
911 assert(!pos.in_check());
912 assert((queeningPath & pos.occupied_squares()) == (queeningPath & pos.pieces(c)));
914 // Add moves needed to free the path from friendly pieces and retest condition
915 movesToGo += popcount<Max15>(queeningPath & pos.pieces(c));
917 if (movesToGo >= oppMovesToGo && !pathDefended)
920 pliesToGo = 2 * movesToGo - int(c == pos.side_to_move());
921 pliesToQueen[c] = std::min(pliesToQueen[c], pliesToGo);
925 // Step 2. If either side cannot promote at least three plies before the other side then situation
926 // becomes too complex and we give up. Otherwise we determine the possibly "winning side"
927 if (abs(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3)
930 winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK);
931 loserSide = ~winnerSide;
933 // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
934 b = candidates = pos.pieces(PAWN, loserSide);
940 // Compute plies from queening
941 queeningSquare = relative_square(loserSide, make_square(file_of(s), RANK_8));
942 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
943 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
945 // Check if (without even considering any obstacles) we're too far away or doubled
946 if ( pliesToQueen[winnerSide] + 3 <= pliesToGo
947 || (squares_in_front_of(loserSide, s) & pos.pieces(PAWN, loserSide)))
948 clear_bit(&candidates, s);
951 // If any candidate is already a passed pawn it _may_ promote in time. We give up.
952 if (candidates & ei.pi->passed_pawns(loserSide))
955 // Step 4. Check new passed pawn creation through king capturing and pawn sacrifices
961 sacptg = blockersCount = 0;
962 minKingDist = kingptg = 256;
964 // Compute plies from queening
965 queeningSquare = relative_square(loserSide, make_square(file_of(s), RANK_8));
966 movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2);
967 pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move());
969 // Generate list of blocking pawns and supporters
970 supporters = adjacent_files_bb(file_of(s)) & candidates;
971 opposed = squares_in_front_of(loserSide, s) & pos.pieces(PAWN, winnerSide);
972 blockers = passed_pawn_mask(loserSide, s) & pos.pieces(PAWN, winnerSide);
976 // How many plies does it take to remove all the blocking pawns?
979 blockSq = pop_1st_bit(&blockers);
982 // Check pawns that can give support to overcome obstacle, for instance
983 // black pawns: a4, b4 white: b2 then pawn in b4 is giving support.
986 b2 = supporters & in_front_bb(winnerSide, blockSq + pawn_push(winnerSide));
988 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
990 d = square_distance(blockSq, pop_1st_bit(&b2)) - 2;
991 movesToGo = std::min(movesToGo, d);
995 // Check pawns that can be sacrificed against the blocking pawn
996 b2 = attack_span_mask(winnerSide, blockSq) & candidates & ~(1ULL << s);
998 while (b2) // This while-loop could be replaced with LSB/MSB (depending on color)
1000 d = square_distance(blockSq, pop_1st_bit(&b2)) - 2;
1001 movesToGo = std::min(movesToGo, d);
1004 // If obstacle can be destroyed with an immediate pawn exchange / sacrifice,
1005 // it's not a real obstacle and we have nothing to add to pliesToGo.
1009 // Plies needed to sacrifice against all the blocking pawns
1010 sacptg += movesToGo * 2;
1013 // Plies needed for the king to capture all the blocking pawns
1014 d = square_distance(pos.king_square(loserSide), blockSq);
1015 minKingDist = std::min(minKingDist, d);
1016 kingptg = (minKingDist + blockersCount) * 2;
1019 // Check if pawn sacrifice plan _may_ save the day
1020 if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg)
1023 // Check if king capture plan _may_ save the day (contains some false positives)
1024 if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg)
1028 // Winning pawn is unstoppable and will promote as first, return big score
1029 Score score = make_score(0, (Value) 0x500 - 0x20 * pliesToQueen[winnerSide]);
1030 return winnerSide == WHITE ? score : -score;
1034 // evaluate_space() computes the space evaluation for a given side. The
1035 // space evaluation is a simple bonus based on the number of safe squares
1036 // available for minor pieces on the central four files on ranks 2--4. Safe
1037 // squares one, two or three squares behind a friendly pawn are counted
1038 // twice. Finally, the space bonus is scaled by a weight taken from the
1039 // material hash table. The aim is to improve play on game opening.
1041 int evaluate_space(const Position& pos, EvalInfo& ei) {
1043 const Color Them = (Us == WHITE ? BLACK : WHITE);
1045 // Find the safe squares for our pieces inside the area defined by
1046 // SpaceMask[]. A square is unsafe if it is attacked by an enemy
1047 // pawn, or if it is undefended and attacked by an enemy piece.
1048 Bitboard safe = SpaceMask[Us]
1049 & ~pos.pieces(PAWN, Us)
1050 & ~ei.attackedBy[Them][PAWN]
1051 & (ei.attackedBy[Us][0] | ~ei.attackedBy[Them][0]);
1053 // Find all squares which are at most three squares behind some friendly pawn
1054 Bitboard behind = pos.pieces(PAWN, Us);
1055 behind |= (Us == WHITE ? behind >> 8 : behind << 8);
1056 behind |= (Us == WHITE ? behind >> 16 : behind << 16);
1058 return popcount<Max15>(safe) + popcount<Max15>(behind & safe);
1062 // apply_weight() applies an evaluation weight to a value trying to prevent overflow
1064 inline Score apply_weight(Score v, Score w) {
1065 return make_score((int(mg_value(v)) * mg_value(w)) / 0x100,
1066 (int(eg_value(v)) * eg_value(w)) / 0x100);
1070 // scale_by_game_phase() interpolates between a middle game and an endgame score,
1071 // based on game phase. It also scales the return value by a ScaleFactor array.
1073 Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf) {
1075 assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
1076 assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
1077 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1079 int ev = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
1080 int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128;
1081 return Value((result + GrainSize / 2) & ~(GrainSize - 1));
1085 // weight_option() computes the value of an evaluation weight, by combining
1086 // two UCI-configurable weights (midgame and endgame) with an internal weight.
1088 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
1090 // Scale option value from 100 to 256
1091 int mg = Options[mgOpt] * 256 / 100;
1092 int eg = Options[egOpt] * 256 / 100;
1094 return apply_weight(make_score(mg, eg), internalWeight);
1098 // init_safety() initizes the king safety evaluation, based on UCI
1099 // parameters. It is called from read_weights().
1101 void init_safety() {
1103 const Value MaxSlope = Value(30);
1104 const Value Peak = Value(1280);
1107 // First setup the base table
1108 for (int i = 0; i < 100; i++)
1110 t[i] = Value(int(0.4 * i * i));
1113 t[i] = std::min(t[i], t[i - 1] + MaxSlope);
1115 t[i] = std::min(t[i], Peak);
1118 // Then apply the weights and get the final KingDangerTable[] array
1119 for (Color c = WHITE; c <= BLACK; c++)
1120 for (int i = 0; i < 100; i++)
1121 KingDangerTable[c][i] = apply_weight(make_score(t[i], 0), Weights[KingDangerUs + c]);
1125 // A couple of little helpers used by tracing code, to_cp() converts a value to
1126 // a double in centipawns scale, trace_add() stores white and black scores.
1128 double to_cp(Value v) { return double(v) / double(PawnValueMidgame); }
1130 void trace_add(int idx, Score wScore, Score bScore) {
1132 TracedScores[WHITE][idx] = wScore;
1133 TracedScores[BLACK][idx] = bScore;
1136 // trace_row() is an helper function used by tracing code to register the
1137 // values of a single evaluation term.
1139 void trace_row(const char *name, int idx) {
1141 Score wScore = TracedScores[WHITE][idx];
1142 Score bScore = TracedScores[BLACK][idx];
1145 case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL:
1146 TraceStream << std::setw(20) << name << " | --- --- | --- --- | "
1147 << std::setw(6) << to_cp(mg_value(wScore)) << " "
1148 << std::setw(6) << to_cp(eg_value(wScore)) << " \n";
1151 TraceStream << std::setw(20) << name << " | " << std::noshowpos
1152 << std::setw(5) << to_cp(mg_value(wScore)) << " "
1153 << std::setw(5) << to_cp(eg_value(wScore)) << " | "
1154 << std::setw(5) << to_cp(mg_value(bScore)) << " "
1155 << std::setw(5) << to_cp(eg_value(bScore)) << " | "
1157 << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " "
1158 << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n";
1164 /// trace_evaluate() is like evaluate() but instead of a value returns a string
1165 /// suitable to be print on stdout with the detailed descriptions and values of
1166 /// each evaluation term. Used mainly for debugging.
1168 std::string trace_evaluate(const Position& pos) {
1173 TraceStream.str("");
1174 TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
1175 memset(TracedScores, 0, 2 * 16 * sizeof(Score));
1177 do_evaluate<true>(pos, margin);
1179 totals = TraceStream.str();
1180 TraceStream.str("");
1182 TraceStream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
1183 << " | MG EG | MG EG | MG EG \n"
1184 << "---------------------+-------------+-------------+---------------\n";
1186 trace_row("Material, PST, Tempo", PST);
1187 trace_row("Material imbalance", IMBALANCE);
1188 trace_row("Pawns", PAWN);
1189 trace_row("Knights", KNIGHT);
1190 trace_row("Bishops", BISHOP);
1191 trace_row("Rooks", ROOK);
1192 trace_row("Queens", QUEEN);
1193 trace_row("Mobility", MOBILITY);
1194 trace_row("King safety", KING);
1195 trace_row("Threats", THREAT);
1196 trace_row("Passed pawns", PASSED);
1197 trace_row("Unstoppable pawns", UNSTOPPABLE);
1198 trace_row("Space", SPACE);
1200 TraceStream << "---------------------+-------------+-------------+---------------\n";
1201 trace_row("Total", TOTAL);
1202 TraceStream << totals;
1204 return TraceStream.str();