2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2010 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/>.
35 #include "ucioption.h"
39 //// Local definitions
44 // Struct EvalInfo contains various information computed and collected
45 // by the evaluation functions.
48 // Pointer to pawn hash table entry
51 // attackedBy[color][piece type] is a bitboard representing all squares
52 // attacked by a given color and piece type, attackedBy[color][0] contains
53 // all squares attacked by the given color.
54 Bitboard attackedBy[2][8];
56 // kingZone[color] is the zone around the enemy king which is considered
57 // by the king safety evaluation. This consists of the squares directly
58 // adjacent to the king, and the three (or two, for a king on an edge file)
59 // squares two ranks in front of the king. For instance, if black's king
60 // is on g8, kingZone[WHITE] is a bitboard containing the squares f8, h8,
61 // f7, g7, h7, f6, g6 and h6.
64 // kingAttackersCount[color] is the number of pieces of the given color
65 // which attack a square in the kingZone of the enemy king.
66 int kingAttackersCount[2];
68 // kingAttackersWeight[color] is the sum of the "weight" of the pieces of the
69 // given color which attack a square in the kingZone of the enemy king. The
70 // weights of the individual piece types are given by the variables
71 // QueenAttackWeight, RookAttackWeight, BishopAttackWeight and
72 // KnightAttackWeight in evaluate.cpp
73 int kingAttackersWeight[2];
75 // kingAdjacentZoneAttacksCount[color] is the number of attacks to squares
76 // directly adjacent to the king of the given color. Pieces which attack
77 // more than one square are counted multiple times. For instance, if black's
78 // king is on g8 and there's a white knight on g5, this knight adds
79 // 2 to kingAdjacentZoneAttacksCount[BLACK].
80 int kingAdjacentZoneAttacksCount[2];
83 // Evaluation grain size, must be a power of 2
84 const int GrainSize = 8;
86 // Evaluation weights, initialized from UCI options
87 enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem };
91 #define S(mg, eg) make_score(mg, eg)
93 // Internal evaluation weights. These are applied on top of the evaluation
94 // weights read from UCI parameters. The purpose is to be able to change
95 // the evaluation weights while keeping the default values of the UCI
96 // parameters at 100, which looks prettier.
98 // Values modified by Joona Kiiski
99 const Score WeightsInternal[] = {
100 S(248, 271), S(233, 201), S(252, 259), S(46, 0), S(247, 0), S(259, 0)
103 // MobilityBonus[PieceType][attacked] contains mobility bonuses for middle and
104 // end game, indexed by piece type and number of attacked squares not occupied
105 // by friendly pieces.
106 const Score MobilityBonus[][32] = {
108 { S(-38,-33), S(-25,-23), S(-12,-13), S( 0, -3), S(12, 7), S(25, 17), // Knights
109 S( 31, 22), S( 38, 27), S( 38, 27) },
110 { S(-25,-30), S(-11,-16), S( 3, -2), S(17, 12), S(31, 26), S(45, 40), // Bishops
111 S( 57, 52), S( 65, 60), S( 71, 65), S(74, 69), S(76, 71), S(78, 73),
112 S( 79, 74), S( 80, 75), S( 81, 76), S(81, 76) },
113 { S(-20,-36), S(-14,-19), S( -8, -3), S(-2, 13), S( 4, 29), S(10, 46), // Rooks
114 S( 14, 62), S( 19, 79), S( 23, 95), S(26,106), S(27,111), S(28,114),
115 S( 29,116), S( 30,117), S( 31,118), S(32,118) },
116 { S(-10,-18), S( -8,-13), S( -6, -7), S(-3, -2), S(-1, 3), S( 1, 8), // Queens
117 S( 3, 13), S( 5, 19), S( 8, 23), S(10, 27), S(12, 32), S(15, 34),
118 S( 16, 35), S( 17, 35), S( 18, 35), S(20, 35), S(20, 35), S(20, 35),
119 S( 20, 35), S( 20, 35), S( 20, 35), S(20, 35), S(20, 35), S(20, 35),
120 S( 20, 35), S( 20, 35), S( 20, 35), S(20, 35), S(20, 35), S(20, 35),
121 S( 20, 35), S( 20, 35) }
124 // OutpostBonus[PieceType][Square] contains outpost bonuses of knights and
125 // bishops, indexed by piece type and square (from white's point of view).
126 const Value OutpostBonus[][64] = {
129 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Knights
130 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
131 V(0), V(0), V(4), V(8), V(8), V(4), V(0), V(0),
132 V(0), V(4),V(17),V(26),V(26),V(17), V(4), V(0),
133 V(0), V(8),V(26),V(35),V(35),V(26), V(8), V(0),
134 V(0), V(4),V(17),V(17),V(17),V(17), V(4), V(0) },
136 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // Bishops
137 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0),
138 V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0),
139 V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0),
140 V(0),V(10),V(21),V(21),V(21),V(21),V(10), V(0),
141 V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0) }
144 // ThreatBonus[attacking][attacked] contains threat bonuses according to
145 // which piece type attacks which one.
146 const Score ThreatBonus[][8] = {
148 { S(0, 0), S( 7, 39), S( 0, 0), S(24, 49), S(41,100), S(41,100) }, // KNIGHT
149 { S(0, 0), S( 7, 39), S(24, 49), S( 0, 0), S(41,100), S(41,100) }, // BISHOP
150 { S(0, 0), S(-1, 29), S(15, 49), S(15, 49), S( 0, 0), S(24, 49) }, // ROOK
151 { S(0, 0), S(15, 39), S(15, 39), S(15, 39), S(15, 39), S( 0, 0) } // QUEEN
154 // ThreatedByPawnPenalty[PieceType] contains a penalty according to which
155 // piece type is attacked by an enemy pawn.
156 const Score ThreatedByPawnPenalty[] = {
157 S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
162 // Rooks and queens on the 7th rank (modified by Joona Kiiski)
163 const Score RookOn7thBonus = make_score(47, 98);
164 const Score QueenOn7thBonus = make_score(27, 54);
166 // Rooks on open files (modified by Joona Kiiski)
167 const Score RookOpenFileBonus = make_score(43, 43);
168 const Score RookHalfOpenFileBonus = make_score(19, 19);
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 // The SpaceMask[Color] contains the area of the board which is considered
180 // by the space evaluation. In the middle game, each side is given a bonus
181 // based on how many squares inside this area are safe and available for
182 // friendly minor pieces.
183 const Bitboard SpaceMask[] = {
184 (1ULL << SQ_C2) | (1ULL << SQ_D2) | (1ULL << SQ_E2) | (1ULL << SQ_F2) |
185 (1ULL << SQ_C3) | (1ULL << SQ_D3) | (1ULL << SQ_E3) | (1ULL << SQ_F3) |
186 (1ULL << SQ_C4) | (1ULL << SQ_D4) | (1ULL << SQ_E4) | (1ULL << SQ_F4),
187 (1ULL << SQ_C7) | (1ULL << SQ_D7) | (1ULL << SQ_E7) | (1ULL << SQ_F7) |
188 (1ULL << SQ_C6) | (1ULL << SQ_D6) | (1ULL << SQ_E6) | (1ULL << SQ_F6) |
189 (1ULL << SQ_C5) | (1ULL << SQ_D5) | (1ULL << SQ_E5) | (1ULL << SQ_F5)
192 // King danger constants and variables. The king danger scores are taken
193 // from the KingDangerTable[]. Various little "meta-bonuses" measuring
194 // the strength of the enemy attack are added up into an integer, which
195 // is used as an index to KingDangerTable[].
197 // KingAttackWeights[PieceType] contains king attack weights by piece type
198 const int KingAttackWeights[] = { 0, 0, 2, 2, 3, 5 };
200 // Bonuses for enemy's safe checks
201 const int QueenContactCheckBonus = 6;
202 const int RookContactCheckBonus = 4;
203 const int QueenCheckBonus = 3;
204 const int RookCheckBonus = 2;
205 const int BishopCheckBonus = 1;
206 const int KnightCheckBonus = 1;
208 // InitKingDanger[Square] contains penalties based on the position of the
209 // defending king, indexed by king's square (from white's point of view).
210 const int InitKingDanger[] = {
211 2, 0, 2, 5, 5, 2, 0, 2,
212 2, 2, 4, 8, 8, 4, 2, 2,
213 7, 10, 12, 12, 12, 12, 10, 7,
214 15, 15, 15, 15, 15, 15, 15, 15,
215 15, 15, 15, 15, 15, 15, 15, 15,
216 15, 15, 15, 15, 15, 15, 15, 15,
217 15, 15, 15, 15, 15, 15, 15, 15,
218 15, 15, 15, 15, 15, 15, 15, 15
221 // KingDangerTable[Color][attackUnits] contains the actual king danger
222 // weighted scores, indexed by color and by a calculated integer number.
223 Score KingDangerTable[2][128];
225 // TracedTerms[Color][PieceType || TracedType] contains a breakdown of the
226 // evaluation terms, used when tracing.
227 Score TracedTerms[2][16];
228 std::stringstream TraceStream;
231 PST = 8, IMBALANCE = 9, MOBILITY = 10, THREAT = 11,
232 PASSED = 12, UNSTOPPABLE = 13, SPACE = 14, TOTAL = 15
235 // Pawn and material hash tables, indexed by the current thread id.
236 // We use per-thread tables so that once we get a pointer to an entry
237 // its life time is unlimited and we don't have to care about someone
238 // changing the entry under our feet.
239 MaterialInfoTable* MaterialTable[MAX_THREADS];
240 PawnInfoTable* PawnTable[MAX_THREADS];
242 // Function prototypes
243 template<bool HasPopCnt, bool Trace>
244 Value do_evaluate(const Position& pos, Value& margin);
246 template<Color Us, bool HasPopCnt>
247 void init_eval_info(const Position& pos, EvalInfo& ei);
249 template<Color Us, bool HasPopCnt, bool Trace>
250 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility);
252 template<Color Us, bool HasPopCnt, bool Trace>
253 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]);
256 Score evaluate_threats(const Position& pos, EvalInfo& ei);
258 template<Color Us, bool HasPopCnt>
259 int evaluate_space(const Position& pos, EvalInfo& ei);
262 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
264 template<bool HasPopCnt>
265 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
267 inline Score apply_weight(Score v, Score weight);
268 Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf);
269 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
274 /// prefetchTables() is called in do_move() to prefetch pawn and material
275 /// hash tables data that will be needed shortly after in evaluation.
277 void prefetchTables(Key pKey, Key mKey, int threadID) {
279 PawnTable[threadID]->prefetch(pKey);
280 MaterialTable[threadID]->prefetch(mKey);
284 /// evaluate() is the main evaluation function. It always computes two
285 /// values, an endgame score and a middle game score, and interpolates
286 /// between them based on the remaining material.
287 Value evaluate(const Position& pos, Value& margin) {
289 return CpuHasPOPCNT ? do_evaluate<true, false>(pos, margin)
290 : do_evaluate<false, false>(pos, margin);
295 double to_cp(Value v) { return double(v) / double(PawnValueMidgame); }
297 void trace_add(int idx, Score term_w, Score term_b = Score(0)) {
299 TracedTerms[WHITE][idx] = term_w;
300 TracedTerms[BLACK][idx] = term_b;
303 template<bool HasPopCnt, bool Trace>
304 Value do_evaluate(const Position& pos, Value& margin) {
308 Score mobilityWhite, mobilityBlack;
311 assert(pos.thread() >= 0 && pos.thread() < MAX_THREADS);
312 assert(!pos.is_check());
314 // Initialize value by reading the incrementally updated scores included
315 // in the position object (material + piece square tables).
316 Score bonus = pos.value();
318 // margins[] store the uncertainty estimation of position's evaluation
319 // that typically is used by the search for pruning decisions.
320 margins[WHITE] = margins[BLACK] = VALUE_ZERO;
322 // Probe the material hash table
323 MaterialInfo* mi = MaterialTable[pos.thread()]->get_material_info(pos);
324 bonus += mi->material_value();
326 // If we have a specialized evaluation function for the current material
327 // configuration, call it and return.
328 if (mi->specialized_eval_exists())
331 return mi->evaluate(pos);
334 // Probe the pawn hash table
335 ei.pi = PawnTable[pos.thread()]->get_pawn_info(pos);
336 bonus += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
338 // Initialize attack and king safety bitboards
339 init_eval_info<WHITE, HasPopCnt>(pos, ei);
340 init_eval_info<BLACK, HasPopCnt>(pos, ei);
342 // Evaluate pieces and mobility
343 bonus += evaluate_pieces_of_color<WHITE, HasPopCnt, Trace>(pos, ei, mobilityWhite)
344 - evaluate_pieces_of_color<BLACK, HasPopCnt, Trace>(pos, ei, mobilityBlack);
346 bonus += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]);
348 // Evaluate kings after all other pieces because we need complete attack
349 // information when computing the king safety evaluation.
350 bonus += evaluate_king<WHITE, HasPopCnt, Trace>(pos, ei, margins)
351 - evaluate_king<BLACK, HasPopCnt, Trace>(pos, ei, margins);
353 // Evaluate tactical threats, we need full attack information including king
354 bonus += evaluate_threats<WHITE>(pos, ei)
355 - evaluate_threats<BLACK>(pos, ei);
357 // Evaluate passed pawns, we need full attack information including king
358 bonus += evaluate_passed_pawns<WHITE>(pos, ei)
359 - evaluate_passed_pawns<BLACK>(pos, ei);
361 // If one side has only a king, check whether exists any unstoppable passed pawn
362 if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
364 bonus += evaluate_unstoppable_pawns<HasPopCnt>(pos, ei);
367 trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns<HasPopCnt>(pos, ei));
370 // Evaluate space for both sides, only in middle-game.
371 if (mi->space_weight())
373 int s_w = evaluate_space<WHITE, HasPopCnt>(pos, ei);
374 int s_b = evaluate_space<BLACK, HasPopCnt>(pos, ei);
375 bonus += apply_weight(make_score((s_w - s_b) * mi->space_weight(), 0), Weights[Space]);
378 trace_add(SPACE, apply_weight(make_score(s_w * mi->space_weight(), make_score(0, 0)), Weights[Space]),
379 apply_weight(make_score(s_b * mi->space_weight(), make_score(0, 0)), Weights[Space]));
382 // Scale winning side if position is more drawish that what it appears
383 ScaleFactor sf = eg_value(bonus) > VALUE_DRAW ? mi->scale_factor(pos, WHITE)
384 : mi->scale_factor(pos, BLACK);
385 Phase phase = mi->game_phase();
387 // If we don't already have an unusual scale factor, check for opposite
388 // colored bishop endgames, and use a lower scale for those.
389 if ( phase < PHASE_MIDGAME
390 && pos.opposite_colored_bishops()
391 && sf == SCALE_FACTOR_NORMAL)
393 // Only the two bishops ?
394 if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
395 && pos.non_pawn_material(BLACK) == BishopValueMidgame)
397 // Check for KBP vs KB with only a single pawn that is almost
398 // certainly a draw or at least two pawns.
399 bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
400 sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
403 // Endgame with opposite-colored bishops, but also other pieces. Still
404 // a bit drawish, but not as drawish as with only the two bishops.
405 sf = ScaleFactor(50);
408 // Interpolate between the middle game and the endgame score
409 margin = margins[pos.side_to_move()];
410 Value v = scale_by_game_phase(bonus, phase, sf);
414 trace_add(PST, pos.value());
415 trace_add(IMBALANCE, mi->material_value());
416 trace_add(PAWN, apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]));
417 trace_add(MOBILITY, apply_weight(mobilityWhite, Weights[Mobility]), apply_weight(mobilityBlack, Weights[Mobility]));
418 trace_add(THREAT, evaluate_threats<WHITE>(pos, ei), evaluate_threats<BLACK>(pos, ei));
419 trace_add(PASSED, evaluate_passed_pawns<WHITE>(pos, ei), evaluate_passed_pawns<BLACK>(pos, ei));
420 trace_add(TOTAL, bonus);
421 TraceStream << "\nUncertainty margin: White: " << to_cp(margins[WHITE])
422 << ", Black: " << to_cp(margins[BLACK])
423 << "\nScaling: " << std::noshowpos
424 << std::setw(6) << 100.0 * phase/128.0 << "% MG, "
425 << std::setw(6) << 100.0 * (1.0 - phase/128.0) << "% * "
426 << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
427 << "Total evaluation: " << to_cp(v);
430 return pos.side_to_move() == WHITE ? v : -v;
436 /// init_eval() initializes various tables used by the evaluation function
438 void init_eval(int threads) {
440 assert(threads <= MAX_THREADS);
442 for (int i = 0; i < MAX_THREADS; i++)
447 delete MaterialTable[i];
449 MaterialTable[i] = NULL;
453 PawnTable[i] = new PawnInfoTable();
455 if (!MaterialTable[i])
456 MaterialTable[i] = new MaterialInfoTable();
461 /// quit_eval() releases heap-allocated memory at program termination
469 /// read_weights() reads evaluation weights from the corresponding UCI parameters
471 void read_evaluation_uci_options(Color us) {
473 // King safety is asymmetrical. Our king danger level is weighted by
474 // "Cowardice" UCI parameter, instead the opponent one by "Aggressiveness".
475 const int kingDangerUs = (us == WHITE ? KingDangerUs : KingDangerThem);
476 const int kingDangerThem = (us == WHITE ? KingDangerThem : KingDangerUs);
478 Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
479 Weights[PawnStructure] = weight_option("Pawn Structure (Middle Game)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
480 Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
481 Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
482 Weights[kingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
483 Weights[kingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
485 // If running in analysis mode, make sure we use symmetrical king safety. We do this
486 // by replacing both Weights[kingDangerUs] and Weights[kingDangerThem] by their average.
487 if (Options["UCI_AnalyseMode"].value<bool>())
488 Weights[kingDangerUs] = Weights[kingDangerThem] = (Weights[kingDangerUs] + Weights[kingDangerThem]) / 2;
496 // init_eval_info() initializes king bitboards for given color adding
497 // pawn attacks. To be done at the beginning of the evaluation.
499 template<Color Us, bool HasPopCnt>
500 void init_eval_info(const Position& pos, EvalInfo& ei) {
502 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
503 const Color Them = (Us == WHITE ? BLACK : WHITE);
505 Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
506 ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
508 // Init king safety tables only if we are going to use them
509 if ( pos.piece_count(Us, QUEEN)
510 && pos.non_pawn_material(Us) >= QueenValueMidgame + RookValueMidgame)
512 ei.kingZone[Us] = (b | (Us == WHITE ? b >> 8 : b << 8));
513 b &= ei.attackedBy[Us][PAWN];
514 ei.kingAttackersCount[Us] = b ? count_1s<Max15>(b) / 2 : 0;
515 ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0;
517 ei.kingZone[Us] = ei.kingAttackersCount[Us] = 0;
521 // evaluate_outposts() evaluates bishop and knight outposts squares
523 template<PieceType Piece, Color Us>
524 Score evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
526 const Color Them = (Us == WHITE ? BLACK : WHITE);
528 assert (Piece == BISHOP || Piece == KNIGHT);
530 // Initial bonus based on square
531 Value bonus = OutpostBonus[Piece == BISHOP][relative_square(Us, s)];
533 // Increase bonus if supported by pawn, especially if the opponent has
534 // no minor piece which can exchange the outpost piece.
535 if (bonus && bit_is_set(ei.attackedBy[Us][PAWN], s))
537 if ( pos.pieces(KNIGHT, Them) == EmptyBoardBB
538 && (SquaresByColorBB[square_color(s)] & pos.pieces(BISHOP, Them)) == EmptyBoardBB)
539 bonus += bonus + bonus / 2;
543 return make_score(bonus, bonus);
547 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
549 template<PieceType Piece, Color Us, bool HasPopCnt, bool Trace>
550 Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score& mobility, Bitboard mobilityArea) {
556 Score bonus = SCORE_ZERO;
558 const BitCountType Full = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64 : CNT32;
559 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
560 const Color Them = (Us == WHITE ? BLACK : WHITE);
561 const Square* ptr = pos.piece_list_begin(Us, Piece);
563 ei.attackedBy[Us][Piece] = EmptyBoardBB;
565 while ((s = *ptr++) != SQ_NONE)
567 // Find attacked squares, including x-ray attacks for bishops and rooks
568 if (Piece == KNIGHT || Piece == QUEEN)
569 b = pos.attacks_from<Piece>(s);
570 else if (Piece == BISHOP)
571 b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
572 else if (Piece == ROOK)
573 b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
577 // Update attack info
578 ei.attackedBy[Us][Piece] |= b;
581 if (b & ei.kingZone[Us])
583 ei.kingAttackersCount[Us]++;
584 ei.kingAttackersWeight[Us] += KingAttackWeights[Piece];
585 Bitboard bb = (b & ei.attackedBy[Them][KING]);
587 ei.kingAdjacentZoneAttacksCount[Us] += count_1s<Max15>(bb);
591 mob = (Piece != QUEEN ? count_1s<Max15>(b & mobilityArea)
592 : count_1s<Full >(b & mobilityArea));
594 mobility += MobilityBonus[Piece][mob];
596 // Decrease score if we are attacked by an enemy pawn. Remaining part
597 // of threat evaluation must be done later when we have full attack info.
598 if (bit_is_set(ei.attackedBy[Them][PAWN], s))
599 bonus -= ThreatedByPawnPenalty[Piece];
601 // Bishop and knight outposts squares
602 if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Us))
603 bonus += evaluate_outposts<Piece, Us>(pos, ei, s);
605 // Queen or rook on 7th rank
606 if ( (Piece == ROOK || Piece == QUEEN)
607 && relative_rank(Us, s) == RANK_7
608 && relative_rank(Us, pos.king_square(Them)) == RANK_8)
610 bonus += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
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) + (square_file(s) == FILE_A ? DELTA_E : DELTA_W);
622 if (pos.piece_on(s + d) == make_piece(Us, PAWN))
624 if (!pos.square_is_empty(s + d + pawn_push(Us)))
625 bonus -= 2*TrappedBishopA1H1Penalty;
626 else if (pos.piece_on(s + 2*d) == make_piece(Us, PAWN))
627 bonus -= TrappedBishopA1H1Penalty;
629 bonus -= 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 bonus += RookOpenFileBonus;
644 bonus += 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 ( square_file(ksq) >= FILE_E
655 && square_file(s) > square_file(ksq)
656 && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(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, square_file(ksq)))
660 bonus -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
661 : (TrappedRookPenalty - mob * 16), 0);
663 else if ( square_file(ksq) <= FILE_D
664 && square_file(s) < square_file(ksq)
665 && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(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, square_file(ksq)))
669 bonus -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
670 : (TrappedRookPenalty - mob * 16), 0);
676 TracedTerms[Us][Piece] = bonus;
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);
691 Score bonus = SCORE_ZERO;
693 // Enemy pieces not defended by a pawn and under our attack
694 Bitboard weakEnemies = pos.pieces_of_color(Them)
695 & ~ei.attackedBy[Them][PAWN]
696 & ei.attackedBy[Us][0];
700 // Add bonus according to type of attacked enemy piece and to the
701 // type of attacking piece, from knights to queens. Kings are not
702 // considered because are already handled in king evaluation.
703 for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
705 b = ei.attackedBy[Us][pt1] & weakEnemies;
707 for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
708 if (b & pos.pieces(pt2))
709 bonus += ThreatBonus[pt1][pt2];
715 // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
716 // pieces of a given color.
718 template<Color Us, bool HasPopCnt, bool Trace>
719 Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) {
721 const Color Them = (Us == WHITE ? BLACK : WHITE);
723 Score bonus = mobility = SCORE_ZERO;
725 // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
726 const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces_of_color(Us));
728 bonus += evaluate_pieces<KNIGHT, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
729 bonus += evaluate_pieces<BISHOP, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
730 bonus += evaluate_pieces<ROOK, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
731 bonus += evaluate_pieces<QUEEN, Us, HasPopCnt, Trace>(pos, ei, mobility, mobilityArea);
733 // Sum up all attacked squares
734 ei.attackedBy[Us][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
735 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
736 | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
741 // evaluate_king<>() assigns bonuses and penalties to a king of a given color
743 template<Color Us, bool HasPopCnt, bool Trace>
744 Score evaluate_king(const Position& pos, EvalInfo& ei, Value margins[]) {
746 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
747 const Color Them = (Us == WHITE ? BLACK : WHITE);
749 Bitboard undefended, b, b1, b2, safe;
751 const Square ksq = pos.king_square(Us);
754 Score bonus = ei.pi->king_shelter<Us>(pos, ksq);
756 // King safety. This is quite complicated, and is almost certainly far
757 // from optimally tuned.
758 if ( ei.kingAttackersCount[Them] >= 2
759 && ei.kingAdjacentZoneAttacksCount[Them])
761 // Find the attacked squares around the king which has no defenders
762 // apart from the king itself
763 undefended = ei.attackedBy[Them][0] & ei.attackedBy[Us][KING];
764 undefended &= ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
765 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
766 | ei.attackedBy[Us][QUEEN]);
768 // Initialize the 'attackUnits' variable, which is used later on as an
769 // index to the KingDangerTable[] array. The initial value is based on
770 // the number and types of the enemy's attacking pieces, the number of
771 // attacked and undefended squares around our king, the square of the
772 // king, and the quality of the pawn shelter.
773 attackUnits = Min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
774 + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + count_1s<Max15>(undefended))
775 + InitKingDanger[relative_square(Us, ksq)]
776 - mg_value(ei.pi->king_shelter<Us>(pos, ksq)) / 32;
778 // Analyse enemy's safe queen contact checks. First find undefended
779 // squares around the king attacked by enemy queen...
780 b = undefended & ei.attackedBy[Them][QUEEN] & ~pos.pieces_of_color(Them);
783 // ...then remove squares not supported by another enemy piece
784 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
785 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][ROOK]);
787 attackUnits += QueenContactCheckBonus
789 * (Them == pos.side_to_move() ? 2 : 1);
792 // Analyse enemy's safe rook contact checks. First find undefended
793 // squares around the king attacked by enemy rooks...
794 b = undefended & ei.attackedBy[Them][ROOK] & ~pos.pieces_of_color(Them);
796 // Consider only squares where the enemy rook gives check
797 b &= RookPseudoAttacks[ksq];
801 // ...then remove squares not supported by another enemy piece
802 b &= ( ei.attackedBy[Them][PAWN] | ei.attackedBy[Them][KNIGHT]
803 | ei.attackedBy[Them][BISHOP] | ei.attackedBy[Them][QUEEN]);
805 attackUnits += RookContactCheckBonus
807 * (Them == pos.side_to_move() ? 2 : 1);
810 // Analyse enemy's safe distance checks for sliders and knights
811 safe = ~(pos.pieces_of_color(Them) | ei.attackedBy[Us][0]);
813 b1 = pos.attacks_from<ROOK>(ksq) & safe;
814 b2 = pos.attacks_from<BISHOP>(ksq) & safe;
816 // Enemy queen safe checks
817 b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
819 attackUnits += QueenCheckBonus * count_1s<Max15>(b);
821 // Enemy rooks safe checks
822 b = b1 & ei.attackedBy[Them][ROOK];
824 attackUnits += RookCheckBonus * count_1s<Max15>(b);
826 // Enemy bishops safe checks
827 b = b2 & ei.attackedBy[Them][BISHOP];
829 attackUnits += BishopCheckBonus * count_1s<Max15>(b);
831 // Enemy knights safe checks
832 b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
834 attackUnits += KnightCheckBonus * count_1s<Max15>(b);
836 // To index KingDangerTable[] attackUnits must be in [0, 99] range
837 attackUnits = Min(99, Max(0, attackUnits));
839 // Finally, extract the king danger score from the KingDangerTable[]
840 // array and subtract the score from evaluation. Set also margins[]
841 // value that will be used for pruning because this value can sometimes
842 // be very big, and so capturing a single attacking piece can therefore
843 // result in a score change far bigger than the value of the captured piece.
844 bonus -= KingDangerTable[Us][attackUnits];
845 margins[Us] += mg_value(KingDangerTable[Us][attackUnits]);
849 TracedTerms[Us][KING] = bonus;
855 // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
858 Score evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
860 const Color Them = (Us == WHITE ? BLACK : WHITE);
862 Score bonus = SCORE_ZERO;
863 Bitboard squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
864 Bitboard b = ei.pi->passed_pawns(Us);
870 Square s = pop_1st_bit(&b);
872 assert(pos.pawn_is_passed(Us, s));
874 int r = int(relative_rank(Us, s) - RANK_2);
875 int rr = r * (r - 1);
877 // Base bonus based on rank
878 Value mbonus = Value(20 * rr);
879 Value ebonus = Value(10 * (rr + r + 1));
883 Square blockSq = s + pawn_push(Us);
885 // Adjust bonus based on kings proximity
886 ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 3 * rr);
887 ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
888 ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 6 * rr);
890 // If the pawn is free to advance, increase bonus
891 if (pos.square_is_empty(blockSq))
893 squaresToQueen = squares_in_front_of(Us, s);
894 defendedSquares = squaresToQueen & ei.attackedBy[Us][0];
896 // If there is an enemy rook or queen attacking the pawn from behind,
897 // add all X-ray attacks by the rook or queen. Otherwise consider only
898 // the squares in the pawn's path attacked or occupied by the enemy.
899 if ( (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them))
900 && (squares_in_front_of(Them, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from<ROOK>(s)))
901 unsafeSquares = squaresToQueen;
903 unsafeSquares = squaresToQueen & (ei.attackedBy[Them][0] | pos.pieces_of_color(Them));
905 // If there aren't enemy attacks or pieces along the path to queen give
906 // huge bonus. Even bigger if we protect the pawn's path.
908 ebonus += Value(rr * (squaresToQueen == defendedSquares ? 17 : 15));
910 // OK, there are enemy attacks or pieces (but not pawns). Are those
911 // squares which are attacked by the enemy also attacked by us ?
912 // If yes, big bonus (but smaller than when there are no enemy attacks),
913 // if no, somewhat smaller bonus.
914 ebonus += Value(rr * ((unsafeSquares & defendedSquares) == unsafeSquares ? 13 : 8));
916 // At last, add a small bonus when there are no *friendly* pieces
917 // in the pawn's path.
918 if (!(squaresToQueen & pos.pieces_of_color(Us)))
923 // Increase the bonus if the passed pawn is supported by a friendly pawn
924 // on the same rank and a bit smaller if it's on the previous rank.
925 supportingPawns = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
926 if (supportingPawns & rank_bb(s))
927 ebonus += Value(r * 20);
928 else if (supportingPawns & rank_bb(s - pawn_push(Us)))
929 ebonus += Value(r * 12);
931 // Rook pawns are a special case: They are sometimes worse, and
932 // sometimes better than other passed pawns. It is difficult to find
933 // good rules for determining whether they are good or bad. For now,
934 // we try the following: Increase the value for rook pawns if the
935 // other side has no pieces apart from a knight, and decrease the
936 // value if the other side has a rook or queen.
937 if (square_file(s) == FILE_A || square_file(s) == FILE_H)
939 if (pos.non_pawn_material(Them) <= KnightValueMidgame)
940 ebonus += ebonus / 4;
941 else if (pos.pieces(ROOK, QUEEN, Them))
942 ebonus -= ebonus / 4;
944 bonus += make_score(mbonus, ebonus);
948 // Add the scores to the middle game and endgame eval
949 return apply_weight(bonus, Weights[PassedPawns]);
952 // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides
953 template<bool HasPopCnt>
954 Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
956 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
958 // Step 1. Hunt for unstoppable pawns. If we find at least one, record how many plies
959 // are required for promotion
960 int pliesToGo[2] = {256, 256};
962 for (Color c = WHITE; c <= BLACK; c++)
964 // Skip if other side has non-pawn pieces
965 if (pos.non_pawn_material(opposite_color(c)))
968 Bitboard b = ei.pi->passed_pawns(c);
972 Square s = pop_1st_bit(&b);
973 Square queeningSquare = relative_square(c, make_square(square_file(s), RANK_8));
975 int mtg = RANK_8 - relative_rank(c, s) - int(relative_rank(c, s) == RANK_2);
976 int oppmtg = square_distance(pos.king_square(opposite_color(c)), queeningSquare) - int(c != pos.side_to_move());
977 bool pathDefended = ((ei.attackedBy[c][0] & squares_in_front_of(c, s)) == squares_in_front_of(c, s));
979 if (mtg >= oppmtg && !pathDefended)
982 int blockerCount = count_1s<Max15>(squares_in_front_of(c, s) & pos.occupied_squares());
985 if (mtg >= oppmtg && !pathDefended)
988 int ptg = 2 * mtg - int(c == pos.side_to_move());
990 if (ptg < pliesToGo[c])
995 // Step 2. If either side cannot promote at least three plies before the other side then
996 // situation becomes too complex and we give up. Otherwise we determine the possibly "winning side"
997 if (abs(pliesToGo[WHITE] - pliesToGo[BLACK]) < 3)
998 return make_score(0, 0);
1000 Color winnerSide = (pliesToGo[WHITE] < pliesToGo[BLACK] ? WHITE : BLACK);
1001 Color loserSide = opposite_color(winnerSide);
1003 // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss?
1004 // We collect the potential candidates in potentialBB.
1005 Bitboard pawnBB = pos.pieces(PAWN, loserSide);
1006 Bitboard potentialBB = pawnBB;
1007 const Bitboard passedBB = ei.pi->passed_pawns(loserSide);
1011 Square psq = pop_1st_bit(&pawnBB);
1013 // Check direct advancement
1014 int mtg = RANK_8 - relative_rank(loserSide, psq) - int(relative_rank(loserSide, psq) == RANK_2);
1015 int ptg = 2 * mtg - int(loserSide == pos.side_to_move());
1017 // Check if (without even considering any obstacles) we're too far away
1018 if (pliesToGo[winnerSide] + 3 <= ptg)
1020 clear_bit(&potentialBB, psq);
1024 // If this is passed pawn, then it _may_ promote in time. We give up.
1025 if (bit_is_set(passedBB, psq))
1026 return make_score(0, 0);
1028 // Doubled pawn is worthless
1029 if (squares_in_front_of(loserSide, psq) & (pos.pieces(PAWN, loserSide)))
1031 clear_bit(&potentialBB, psq);
1036 // Step 4. Check new passed pawn creation through king capturing and sacrifises
1037 pawnBB = potentialBB;
1041 Square psq = pop_1st_bit(&pawnBB);
1043 int mtg = RANK_8 - relative_rank(loserSide, psq) - int(relative_rank(loserSide, psq) == RANK_2);
1044 int ptg = 2 * mtg - int(loserSide == pos.side_to_move());
1046 // Generate list of obstacles
1047 Bitboard obsBB = passed_pawn_mask(loserSide, psq) & pos.pieces(PAWN, winnerSide);
1048 const bool pawnIsOpposed = squares_in_front_of(loserSide, psq) & obsBB;
1051 // How many plies does it take to remove all the obstacles?
1053 int realObsCount = 0;
1054 int minKingDist = 256;
1058 Square obSq = pop_1st_bit(&obsBB);
1061 // Check pawns that can give support to overcome obstacle (Eg. wp: a4,b4 bp: b2. b4 is giving support)
1062 if (!pawnIsOpposed && square_file(psq) != square_file(obSq))
1064 Bitboard supBB = in_front_bb(winnerSide, Square(obSq + (winnerSide == WHITE ? 8 : -8)))
1065 & neighboring_files_bb(psq) & potentialBB;
1067 while(supBB) // This while-loop could be replaced with supSq = LSB/MSB(supBB) (depending on color)
1069 Square supSq = pop_1st_bit(&supBB);
1070 int dist = square_distance(obSq, supSq);
1071 minMoves = Min(minMoves, dist - 2);
1076 // Check pawns that can be sacrifised
1077 Bitboard sacBB = passed_pawn_mask(winnerSide, obSq) & neighboring_files_bb(obSq) & potentialBB & ~(1ULL << psq);
1079 while(sacBB) // This while-loop could be replaced with sacSq = LSB/MSB(sacBB) (depending on color)
1081 Square sacSq = pop_1st_bit(&sacBB);
1082 int dist = square_distance(obSq, sacSq);
1083 minMoves = Min(minMoves, dist - 2);
1086 // If obstacle can be destroyed with immediate pawn sacrifise, it's not real obstacle
1090 // Pawn sac calculations
1091 sacptg += minMoves * 2;
1093 // King capture calc
1095 int kingDist = square_distance(pos.king_square(loserSide), obSq);
1096 minKingDist = Min(minKingDist, kingDist);
1099 // Check if pawn sac plan _may_ save the day
1100 if (pliesToGo[winnerSide] + 3 > ptg + sacptg)
1101 return make_score(0, 0);
1103 // Check if king capture plan _may_ save the day (contains some false positives)
1104 int kingptg = (minKingDist + realObsCount) * 2;
1105 if (pliesToGo[winnerSide] + 3 > ptg + kingptg)
1106 return make_score(0, 0);
1109 // Step 5. Assign bonus
1110 const int Sign[2] = {1, -1};
1111 return Sign[winnerSide] * make_score(0, (Value) 0x500 - 0x20 * pliesToGo[winnerSide]);
1115 // evaluate_space() computes the space evaluation for a given side. The
1116 // space evaluation is a simple bonus based on the number of safe squares
1117 // available for minor pieces on the central four files on ranks 2--4. Safe
1118 // squares one, two or three squares behind a friendly pawn are counted
1119 // twice. Finally, the space bonus is scaled by a weight taken from the
1120 // material hash table. The aim is to improve play on game opening.
1121 template<Color Us, bool HasPopCnt>
1122 int evaluate_space(const Position& pos, EvalInfo& ei) {
1124 const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
1125 const Color Them = (Us == WHITE ? BLACK : WHITE);
1127 // Find the safe squares for our pieces inside the area defined by
1128 // SpaceMask[]. A square is unsafe if it is attacked by an enemy
1129 // pawn, or if it is undefended and attacked by an enemy piece.
1130 Bitboard safe = SpaceMask[Us]
1131 & ~pos.pieces(PAWN, Us)
1132 & ~ei.attackedBy[Them][PAWN]
1133 & (ei.attackedBy[Us][0] | ~ei.attackedBy[Them][0]);
1135 // Find all squares which are at most three squares behind some friendly pawn
1136 Bitboard behind = pos.pieces(PAWN, Us);
1137 behind |= (Us == WHITE ? behind >> 8 : behind << 8);
1138 behind |= (Us == WHITE ? behind >> 16 : behind << 16);
1140 return count_1s<Max15>(safe) + count_1s<Max15>(behind & safe);
1144 // apply_weight() applies an evaluation weight to a value trying to prevent overflow
1146 inline Score apply_weight(Score v, Score w) {
1147 return make_score((int(mg_value(v)) * mg_value(w)) / 0x100,
1148 (int(eg_value(v)) * eg_value(w)) / 0x100);
1152 // scale_by_game_phase() interpolates between a middle game and an endgame score,
1153 // based on game phase. It also scales the return value by a ScaleFactor array.
1155 Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf) {
1157 assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
1158 assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
1159 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1161 int ev = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
1162 int result = (mg_value(v) * int(ph) + ev * int(128 - ph)) / 128;
1163 return Value((result + GrainSize / 2) & ~(GrainSize - 1));
1167 // weight_option() computes the value of an evaluation weight, by combining
1168 // two UCI-configurable weights (midgame and endgame) with an internal weight.
1170 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
1172 // Scale option value from 100 to 256
1173 int mg = Options[mgOpt].value<int>() * 256 / 100;
1174 int eg = Options[egOpt].value<int>() * 256 / 100;
1176 return apply_weight(make_score(mg, eg), internalWeight);
1180 // init_safety() initizes the king safety evaluation, based on UCI
1181 // parameters. It is called from read_weights().
1183 void init_safety() {
1185 const Value MaxSlope = Value(30);
1186 const Value Peak = Value(1280);
1189 // First setup the base table
1190 for (int i = 0; i < 100; i++)
1192 t[i] = Value(int(0.4 * i * i));
1195 t[i] = Min(t[i], t[i - 1] + MaxSlope);
1197 t[i] = Min(t[i], Peak);
1200 // Then apply the weights and get the final KingDangerTable[] array
1201 for (Color c = WHITE; c <= BLACK; c++)
1202 for (int i = 0; i < 100; i++)
1203 KingDangerTable[c][i] = apply_weight(make_score(t[i], 0), Weights[KingDangerUs + c]);
1207 // trace_row() is an helper function used by tracing code to register the
1208 // values of a single evaluation term.
1210 void trace_row(const char *name, int idx) {
1212 Score term_w = TracedTerms[WHITE][idx];
1213 Score term_b = TracedTerms[BLACK][idx];
1216 case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL:
1217 TraceStream << std::setw(20) << name << " | --- --- | --- --- | "
1218 << std::setw(6) << to_cp(mg_value(term_w)) << " "
1219 << std::setw(6) << to_cp(eg_value(term_w)) << " \n";
1222 TraceStream << std::setw(20) << name << " | " << std::noshowpos
1223 << std::setw(5) << to_cp(mg_value(term_w)) << " "
1224 << std::setw(5) << to_cp(eg_value(term_w)) << " | "
1225 << std::setw(5) << to_cp(mg_value(term_b)) << " "
1226 << std::setw(5) << to_cp(eg_value(term_b)) << " | "
1228 << std::setw(6) << to_cp(mg_value(term_w - term_b)) << " "
1229 << std::setw(6) << to_cp(eg_value(term_w - term_b)) << " \n";
1235 /// trace_evaluate() is like evaluate() but instead of a value returns a string
1236 /// suitable to be print on stdout with the detailed descriptions and values of
1237 /// each evaluation term. Used mainly for debugging.
1239 std::string trace_evaluate(const Position& pos) {
1244 TraceStream.str("");
1245 TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2);
1246 memset(TracedTerms, 0, 2 * 16 * sizeof(Score));
1248 do_evaluate<false, true>(pos, margin);
1250 totals = TraceStream.str();
1251 TraceStream.str("");
1253 TraceStream << std::setw(21) << "Eval term " << "| White | Black | Total \n"
1254 << " | MG EG | MG EG | MG EG \n"
1255 << "---------------------+-------------+-------------+---------------\n";
1257 trace_row("Material, PST, Tempo", PST);
1258 trace_row("Material imbalance", IMBALANCE);
1259 trace_row("Pawns", PAWN);
1260 trace_row("Knights", KNIGHT);
1261 trace_row("Bishops", BISHOP);
1262 trace_row("Rooks", ROOK);
1263 trace_row("Queens", QUEEN);
1264 trace_row("Mobility", MOBILITY);
1265 trace_row("King safety", KING);
1266 trace_row("Threats", THREAT);
1267 trace_row("Passed pawns", PASSED);
1268 trace_row("Unstoppable pawns", UNSTOPPABLE);
1269 trace_row("Space", SPACE);
1271 TraceStream << "---------------------+-------------+-------------+---------------\n";
1272 trace_row("Total", TOTAL);
1273 TraceStream << totals;
1275 return TraceStream.str();