2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2009 Marco Costalba
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/>.
34 #include "ucioption.h"
38 //// Local definitions
43 const int Sign[2] = { 1, -1 };
45 // Evaluation grain size, must be a power of 2
46 const int GrainSize = 8;
48 // Evaluation weights, initialized from UCI options
49 Score WeightMobility, WeightPawnStructure;
50 Score WeightPassedPawns, WeightSpace;
51 Score WeightKingSafety[2];
53 // Internal evaluation weights. These are applied on top of the evaluation
54 // weights read from UCI parameters. The purpose is to be able to change
55 // the evaluation weights while keeping the default values of the UCI
56 // parameters at 100, which looks prettier.
58 // Values modified by Joona Kiiski
59 const Score WeightMobilityInternal = make_score(248, 271);
60 const Score WeightPawnStructureInternal = make_score(233, 201);
61 const Score WeightPassedPawnsInternal = make_score(252, 259);
62 const Score WeightSpaceInternal = make_score( 46, 0);
63 const Score WeightKingSafetyInternal = make_score(247, 0);
64 const Score WeightKingOppSafetyInternal = make_score(259, 0);
66 // Mobility and outposts bonus modified by Joona Kiiski
69 #define S(mg, eg) make_score(mg, eg)
73 // Knight mobility bonus in middle game and endgame, indexed by the number
74 // of attacked squares not occupied by friendly piecess.
75 const Score KnightMobilityBonus[16] = {
76 S(-38,-33), S(-25,-23), S(-12,-13), S( 0,-3),
77 S( 12, 7), S( 25, 17), S( 31, 22), S(38, 27), S(38, 27)
80 // Bishop mobility bonus in middle game and endgame, indexed by the number
81 // of attacked squares not occupied by friendly pieces. X-ray attacks through
82 // queens are also included.
83 const Score BishopMobilityBonus[16] = {
84 S(-25,-30), S(-11,-16), S( 3, -2), S(17, 12),
85 S( 31, 26), S( 45, 40), S(57, 52), S(65, 60),
86 S( 71, 65), S( 74, 69), S(76, 71), S(78, 73),
87 S( 79, 74), S( 80, 75), S(81, 76), S(81, 76)
90 // Rook mobility bonus in middle game and endgame, indexed by the number
91 // of attacked squares not occupied by friendly pieces. X-ray attacks through
92 // queens and rooks are also included.
93 const Score RookMobilityBonus[16] = {
94 S(-20,-36), S(-14,-19), S(-8, -3), S(-2, 13),
95 S( 4, 29), S( 10, 46), S(14, 62), S(19, 79),
96 S( 23, 95), S( 26,106), S(27,111), S(28,114),
97 S( 29,116), S( 30,117), S(31,118), S(32,118)
100 // Queen mobility bonus in middle game and endgame, indexed by the number
101 // of attacked squares not occupied by friendly pieces.
102 const Score QueenMobilityBonus[32] = {
103 S(-10,-18), S(-8,-13), S(-6, -7), S(-3, -2), S(-1, 3), S( 1, 8),
104 S( 3, 13), S( 5, 19), S( 8, 23), S(10, 27), S(12, 32), S(15, 34),
105 S( 16, 35), S(17, 35), S(18, 35), S(20, 35), S(20, 35), S(20, 35),
106 S( 20, 35), S(20, 35), S(20, 35), S(20, 35), S(20, 35), S(20, 35),
107 S( 20, 35), S(20, 35), S(20, 35), S(20, 35), S(20, 35), S(20, 35),
108 S( 20, 35), S(20, 35)
111 // Pointers table to access mobility tables through piece type
112 const Score* MobilityBonus[8] = { 0, 0, KnightMobilityBonus, BishopMobilityBonus,
113 RookMobilityBonus, QueenMobilityBonus, 0, 0 };
115 // Outpost bonuses for knights and bishops, indexed by square (from white's
117 const Value KnightOutpostBonus[64] = {
119 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 1
120 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 2
121 V(0), V(0), V(4), V(8), V(8), V(4), V(0), V(0), // 3
122 V(0), V(4),V(17),V(26),V(26),V(17), V(4), V(0), // 4
123 V(0), V(8),V(26),V(35),V(35),V(26), V(8), V(0), // 5
124 V(0), V(4),V(17),V(17),V(17),V(17), V(4), V(0), // 6
125 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 7
126 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8
129 const Value BishopOutpostBonus[64] = {
131 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 1
132 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 2
133 V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0), // 3
134 V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0), // 4
135 V(0),V(10),V(21),V(21),V(21),V(21),V(10), V(0), // 5
136 V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0), // 6
137 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 7
138 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8
141 // ThreatBonus[][] contains bonus according to which piece type
142 // attacks which one.
145 const Score ThreatBonus[8][8] = {
146 { Z, Z, Z, Z, Z, Z, Z, Z }, // not used
147 { Z, S(18,37), Z, S(37,47), S(55,97), S(55,97), Z, Z }, // KNIGHT attacks
148 { Z, S(18,37), S(37,47), Z, S(55,97), S(55,97), Z, Z }, // BISHOP attacks
149 { Z, S( 9,27), S(27,47), S(27,47), Z, S(37,47), Z, Z }, // ROOK attacks
150 { Z, S(27,37), S(27,37), S(27,37), S(27,37), Z, Z, Z }, // QUEEN attacks
151 { Z, Z, Z, Z, Z, Z, Z, Z }, // not used
152 { Z, Z, Z, Z, Z, Z, Z, Z }, // not used
153 { Z, Z, Z, Z, Z, Z, Z, Z } // not used
156 // ThreatedByPawnPenalty[] contains a penalty according to which piece
157 // type is attacked by an enemy pawn.
158 const Score ThreatedByPawnPenalty[8] = {
159 Z, Z, S(56, 70), S(56, 70), S(76, 99), S(86, 118), Z, Z
165 // Bonus for unstoppable passed pawns
166 const Value UnstoppablePawnValue = Value(0x500);
168 // Rooks and queens on the 7th rank (modified by Joona Kiiski)
169 const Score RookOn7thBonus = make_score(47, 98);
170 const Score QueenOn7thBonus = make_score(27, 54);
172 // Rooks on open files (modified by Joona Kiiski)
173 const Score RookOpenFileBonus = make_score(43, 43);
174 const Score RookHalfOpenFileBonus = make_score(19, 19);
176 // Penalty for rooks trapped inside a friendly king which has lost the
178 const Value TrappedRookPenalty = Value(180);
180 // Penalty for a bishop on a7/h7 (a2/h2 for black) which is trapped by
182 const Score TrappedBishopA7H7Penalty = make_score(300, 300);
184 // Bitboard masks for detecting trapped bishops on a7/h7 (a2/h2 for black)
185 const Bitboard MaskA7H7[2] = {
186 ((1ULL << SQ_A7) | (1ULL << SQ_H7)),
187 ((1ULL << SQ_A2) | (1ULL << SQ_H2))
190 // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
191 // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
192 // happen in Chess960 games.
193 const Score TrappedBishopA1H1Penalty = make_score(100, 100);
195 // Bitboard masks for detecting trapped bishops on a1/h1 (a8/h8 for black)
196 const Bitboard MaskA1H1[2] = {
197 ((1ULL << SQ_A1) | (1ULL << SQ_H1)),
198 ((1ULL << SQ_A8) | (1ULL << SQ_H8))
201 // The SpaceMask[color] contains the area of the board which is considered
202 // by the space evaluation. In the middle game, each side is given a bonus
203 // based on how many squares inside this area are safe and available for
204 // friendly minor pieces.
205 const Bitboard SpaceMask[2] = {
206 (1ULL<<SQ_C2) | (1ULL<<SQ_D2) | (1ULL<<SQ_E2) | (1ULL<<SQ_F2) |
207 (1ULL<<SQ_C3) | (1ULL<<SQ_D3) | (1ULL<<SQ_E3) | (1ULL<<SQ_F3) |
208 (1ULL<<SQ_C4) | (1ULL<<SQ_D4) | (1ULL<<SQ_E4) | (1ULL<<SQ_F4),
209 (1ULL<<SQ_C7) | (1ULL<<SQ_D7) | (1ULL<<SQ_E7) | (1ULL<<SQ_F7) |
210 (1ULL<<SQ_C6) | (1ULL<<SQ_D6) | (1ULL<<SQ_E6) | (1ULL<<SQ_F6) |
211 (1ULL<<SQ_C5) | (1ULL<<SQ_D5) | (1ULL<<SQ_E5) | (1ULL<<SQ_F5)
214 /// King safety constants and variables. The king safety scores are taken
215 /// from the array SafetyTable[]. Various little "meta-bonuses" measuring
216 /// the strength of the attack are added up into an integer, which is used
217 /// as an index to SafetyTable[].
219 // Attack weights for each piece type and table indexed on piece type
220 const int QueenAttackWeight = 5;
221 const int RookAttackWeight = 3;
222 const int BishopAttackWeight = 2;
223 const int KnightAttackWeight = 2;
225 const int AttackWeight[] = { 0, 0, KnightAttackWeight, BishopAttackWeight, RookAttackWeight, QueenAttackWeight };
227 // Bonuses for safe checks, initialized from UCI options
228 int QueenContactCheckBonus, DiscoveredCheckBonus;
229 int QueenCheckBonus, RookCheckBonus, BishopCheckBonus, KnightCheckBonus;
231 // Scan for queen contact mates?
232 const bool QueenContactMates = true;
234 // Bonus for having a mate threat, initialized from UCI options
237 // InitKingDanger[] contains bonuses based on the position of the defending
239 const int InitKingDanger[64] = {
240 2, 0, 2, 5, 5, 2, 0, 2,
241 2, 2, 4, 8, 8, 4, 2, 2,
242 7, 10, 12, 12, 12, 12, 10, 7,
243 15, 15, 15, 15, 15, 15, 15, 15,
244 15, 15, 15, 15, 15, 15, 15, 15,
245 15, 15, 15, 15, 15, 15, 15, 15,
246 15, 15, 15, 15, 15, 15, 15, 15,
247 15, 15, 15, 15, 15, 15, 15, 15
250 // SafetyTable[] contains the actual king safety scores. It is initialized
252 Value SafetyTable[100];
254 // Pawn and material hash tables, indexed by the current thread id.
255 // Note that they will be initialized at 0 being global variables.
256 MaterialInfoTable* MaterialTable[THREAD_MAX];
257 PawnInfoTable* PawnTable[THREAD_MAX];
259 // Sizes of pawn and material hash tables
260 const int PawnTableSize = 16384;
261 const int MaterialTableSize = 1024;
263 // Function prototypes
264 template<bool HasPopCnt>
265 Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID);
267 template<Color Us, bool HasPopCnt>
268 void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei);
270 template<Color Us, bool HasPopCnt>
271 void evaluate_king(const Position& pos, EvalInfo& ei);
274 void evaluate_threats(const Position& pos, EvalInfo& ei);
276 template<Color Us, bool HasPopCnt>
277 void evaluate_space(const Position& pos, EvalInfo& ei);
279 void evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
280 void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo& ei);
281 void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei);
282 inline Score apply_weight(Score v, Score weight);
283 Value scale_by_game_phase(const Score& v, Phase ph, const ScaleFactor sf[]);
284 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
293 /// evaluate() is the main evaluation function. It always computes two
294 /// values, an endgame score and a middle game score, and interpolates
295 /// between them based on the remaining material.
296 Value evaluate(const Position& pos, EvalInfo& ei, int threadID) {
298 return CpuHasPOPCNT ? do_evaluate<true>(pos, ei, threadID)
299 : do_evaluate<false>(pos, ei, threadID);
304 template<bool HasPopCnt>
305 Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID) {
308 assert(threadID >= 0 && threadID < THREAD_MAX);
309 assert(!pos.is_check());
311 memset(&ei, 0, sizeof(EvalInfo));
313 // Initialize by reading the incrementally updated scores included in the
314 // position object (material + piece square tables)
315 ei.value = pos.value();
317 // Probe the material hash table
318 ei.mi = MaterialTable[threadID]->get_material_info(pos);
319 ei.value += ei.mi->material_value();
321 // If we have a specialized evaluation function for the current material
322 // configuration, call it and return
323 if (ei.mi->specialized_eval_exists())
324 return ei.mi->evaluate(pos);
326 // After get_material_info() call that modifies them
327 ScaleFactor factor[2];
328 factor[WHITE] = ei.mi->scale_factor(pos, WHITE);
329 factor[BLACK] = ei.mi->scale_factor(pos, BLACK);
331 // Probe the pawn hash table
332 ei.pi = PawnTable[threadID]->get_pawn_info(pos);
333 ei.value += apply_weight(ei.pi->pawns_value(), WeightPawnStructure);
335 // Initialize king attack bitboards and king attack zones for both sides
336 ei.attackedBy[WHITE][KING] = pos.attacks_from<KING>(pos.king_square(WHITE));
337 ei.attackedBy[BLACK][KING] = pos.attacks_from<KING>(pos.king_square(BLACK));
338 ei.kingZone[WHITE] = ei.attackedBy[BLACK][KING] | (ei.attackedBy[BLACK][KING] >> 8);
339 ei.kingZone[BLACK] = ei.attackedBy[WHITE][KING] | (ei.attackedBy[WHITE][KING] << 8);
341 // Initialize pawn attack bitboards for both sides
342 ei.attackedBy[WHITE][PAWN] = ei.pi->pawn_attacks(WHITE);
343 ei.attackedBy[BLACK][PAWN] = ei.pi->pawn_attacks(BLACK);
344 Bitboard b1 = ei.attackedBy[WHITE][PAWN] & ei.attackedBy[BLACK][KING];
345 Bitboard b2 = ei.attackedBy[BLACK][PAWN] & ei.attackedBy[WHITE][KING];
347 ei.kingAttackersCount[WHITE] = count_1s_max_15<HasPopCnt>(b1)/2;
350 ei.kingAttackersCount[BLACK] = count_1s_max_15<HasPopCnt>(b2)/2;
353 evaluate_pieces_of_color<WHITE, HasPopCnt>(pos, ei);
354 evaluate_pieces_of_color<BLACK, HasPopCnt>(pos, ei);
356 // Kings. Kings are evaluated after all other pieces for both sides,
357 // because we need complete attack information for all pieces when computing
358 // the king safety evaluation.
359 evaluate_king<WHITE, HasPopCnt>(pos, ei);
360 evaluate_king<BLACK, HasPopCnt>(pos, ei);
362 // Evaluate tactical threats, we need full attack info
363 evaluate_threats<WHITE>(pos, ei);
364 evaluate_threats<BLACK>(pos, ei);
366 // Evaluate passed pawns. We evaluate passed pawns for both sides at once,
367 // because we need to know which side promotes first in positions where
368 // both sides have an unstoppable passed pawn. To be called after all attacks
369 // are computed, included king.
370 if (ei.pi->passed_pawns())
371 evaluate_passed_pawns(pos, ei);
373 Phase phase = ei.mi->game_phase();
375 // Middle-game specific evaluation terms
376 if (phase > PHASE_ENDGAME)
378 // Pawn storms in positions with opposite castling.
379 if ( square_file(pos.king_square(WHITE)) >= FILE_E
380 && square_file(pos.king_square(BLACK)) <= FILE_D)
382 ei.value += make_score(ei.pi->queenside_storm_value(WHITE) - ei.pi->kingside_storm_value(BLACK), 0);
384 else if ( square_file(pos.king_square(WHITE)) <= FILE_D
385 && square_file(pos.king_square(BLACK)) >= FILE_E)
387 ei.value += make_score(ei.pi->kingside_storm_value(WHITE) - ei.pi->queenside_storm_value(BLACK), 0);
389 // Evaluate space for both sides
390 if (ei.mi->space_weight() > 0)
392 evaluate_space<WHITE, HasPopCnt>(pos, ei);
393 evaluate_space<BLACK, HasPopCnt>(pos, ei);
398 ei.value += apply_weight(ei.mobility, WeightMobility);
400 // If we don't already have an unusual scale factor, check for opposite
401 // colored bishop endgames, and use a lower scale for those
402 if ( phase < PHASE_MIDGAME
403 && pos.opposite_colored_bishops()
404 && ( (factor[WHITE] == SCALE_FACTOR_NORMAL && eg_value(ei.value) > Value(0))
405 || (factor[BLACK] == SCALE_FACTOR_NORMAL && eg_value(ei.value) < Value(0))))
409 // Only the two bishops ?
410 if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
411 && pos.non_pawn_material(BLACK) == BishopValueMidgame)
413 // Check for KBP vs KB with only a single pawn that is almost
414 // certainly a draw or at least two pawns.
415 bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
416 sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
419 // Endgame with opposite-colored bishops, but also other pieces. Still
420 // a bit drawish, but not as drawish as with only the two bishops.
421 sf = ScaleFactor(50);
423 if (factor[WHITE] == SCALE_FACTOR_NORMAL)
425 if (factor[BLACK] == SCALE_FACTOR_NORMAL)
429 // Interpolate between the middle game and the endgame score
430 Color stm = pos.side_to_move();
432 Value v = Sign[stm] * scale_by_game_phase(ei.value, phase, factor);
434 return (ei.mateThreat[stm] == MOVE_NONE ? v : 8 * QueenValueMidgame - v);
439 /// init_eval() initializes various tables used by the evaluation function
441 void init_eval(int threads) {
443 assert(threads <= THREAD_MAX);
445 for (int i = 0; i < THREAD_MAX; i++)
450 delete MaterialTable[i];
452 MaterialTable[i] = NULL;
456 PawnTable[i] = new PawnInfoTable(PawnTableSize);
457 if (!MaterialTable[i])
458 MaterialTable[i] = new MaterialInfoTable(MaterialTableSize);
463 /// quit_eval() releases heap-allocated memory at program termination
467 for (int i = 0; i < THREAD_MAX; i++)
470 delete MaterialTable[i];
472 MaterialTable[i] = NULL;
477 /// read_weights() reads evaluation weights from the corresponding UCI parameters
479 void read_weights(Color us) {
481 Color them = opposite_color(us);
483 WeightMobility = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightMobilityInternal);
484 WeightPawnStructure = weight_option("Pawn Structure (Middle Game)", "Pawn Structure (Endgame)", WeightPawnStructureInternal);
485 WeightPassedPawns = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightPassedPawnsInternal);
486 WeightSpace = weight_option("Space", "Space", WeightSpaceInternal);
487 WeightKingSafety[us] = weight_option("Cowardice", "Cowardice", WeightKingSafetyInternal);
488 WeightKingSafety[them] = weight_option("Aggressiveness", "Aggressiveness", WeightKingOppSafetyInternal);
490 // If running in analysis mode, make sure we use symmetrical king safety. We do this
491 // by replacing both WeightKingSafety[us] and WeightKingSafety[them] by their average.
492 if (get_option_value_bool("UCI_AnalyseMode"))
494 WeightKingSafety[us] = (WeightKingSafety[us] + WeightKingSafety[them]) / 2;
495 WeightKingSafety[them] = WeightKingSafety[us];
503 // evaluate_outposts() evaluates bishop and knight outposts squares
505 template<PieceType Piece, Color Us>
506 void evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
508 const Color Them = (Us == WHITE ? BLACK : WHITE);
510 // Initial bonus based on square
511 Value bonus = (Piece == BISHOP ? BishopOutpostBonus[relative_square(Us, s)]
512 : KnightOutpostBonus[relative_square(Us, s)]);
514 // Increase bonus if supported by pawn, especially if the opponent has
515 // no minor piece which can exchange the outpost piece
516 if (bonus && bit_is_set(ei.attackedBy[Us][PAWN], s))
518 if ( pos.pieces(KNIGHT, Them) == EmptyBoardBB
519 && (SquaresByColorBB[square_color(s)] & pos.pieces(BISHOP, Them)) == EmptyBoardBB)
520 bonus += bonus + bonus / 2;
524 ei.value += Sign[Us] * make_score(bonus, bonus);
528 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
530 template<PieceType Piece, Color Us, bool HasPopCnt>
531 void evaluate_pieces(const Position& pos, EvalInfo& ei, Bitboard no_mob_area) {
538 const Color Them = (Us == WHITE ? BLACK : WHITE);
539 const Square* ptr = pos.piece_list_begin(Us, Piece);
541 while ((s = *ptr++) != SQ_NONE)
543 // Find attacked squares, including x-ray attacks for bishops and rooks
544 if (Piece == KNIGHT || Piece == QUEEN)
545 b = pos.attacks_from<Piece>(s);
546 else if (Piece == BISHOP)
547 b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
548 else if (Piece == ROOK)
549 b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
553 // Update attack info
554 ei.attackedBy[Us][Piece] |= b;
557 if (b & ei.kingZone[Us])
559 ei.kingAttackersCount[Us]++;
560 ei.kingAttackersWeight[Us] += AttackWeight[Piece];
561 Bitboard bb = (b & ei.attackedBy[Them][KING]);
563 ei.kingAdjacentZoneAttacksCount[Us] += count_1s_max_15<HasPopCnt>(bb);
567 mob = (Piece != QUEEN ? count_1s_max_15<HasPopCnt>(b & no_mob_area)
568 : count_1s<HasPopCnt>(b & no_mob_area));
570 ei.mobility += Sign[Us] * MobilityBonus[Piece][mob];
572 // Decrease score if we are attacked by an enemy pawn. Remaining part
573 // of threat evaluation must be done later when we have full attack info.
574 if (bit_is_set(ei.attackedBy[Them][PAWN], s))
575 ei.value -= Sign[Us] * ThreatedByPawnPenalty[Piece];
577 // Bishop and knight outposts squares
578 if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Them))
579 evaluate_outposts<Piece, Us>(pos, ei, s);
581 // Special patterns: trapped bishops on a7/h7/a2/h2
582 // and trapped bishops on a1/h1/a8/h8 in Chess960.
585 if (bit_is_set(MaskA7H7[Us], s))
586 evaluate_trapped_bishop_a7h7(pos, s, Us, ei);
588 if (Chess960 && bit_is_set(MaskA1H1[Us], s))
589 evaluate_trapped_bishop_a1h1(pos, s, Us, ei);
592 // Queen or rook on 7th rank
593 if ( (Piece == ROOK || Piece == QUEEN)
594 && relative_rank(Us, s) == RANK_7
595 && relative_rank(Us, pos.king_square(Them)) == RANK_8)
597 ei.value += Sign[Us] * (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
600 // Special extra evaluation for rooks
603 // Open and half-open files
605 if (ei.pi->file_is_half_open(Us, f))
607 if (ei.pi->file_is_half_open(Them, f))
608 ei.value += Sign[Us] * RookOpenFileBonus;
610 ei.value += Sign[Us] * RookHalfOpenFileBonus;
613 // Penalize rooks which are trapped inside a king. Penalize more if
614 // king has lost right to castle.
615 if (mob > 6 || ei.pi->file_is_half_open(Us, f))
618 ksq = pos.king_square(Us);
620 if ( square_file(ksq) >= FILE_E
621 && square_file(s) > square_file(ksq)
622 && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
624 // Is there a half-open file between the king and the edge of the board?
625 if (!ei.pi->has_open_file_to_right(Us, square_file(ksq)))
626 ei.value -= Sign[Us] * make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
627 : (TrappedRookPenalty - mob * 16), 0);
629 else if ( square_file(ksq) <= FILE_D
630 && square_file(s) < square_file(ksq)
631 && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
633 // Is there a half-open file between the king and the edge of the board?
634 if (!ei.pi->has_open_file_to_left(Us, square_file(ksq)))
635 ei.value -= Sign[Us] * make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
636 : (TrappedRookPenalty - mob * 16), 0);
643 // evaluate_threats<>() assigns bonuses according to the type of attacking piece
644 // and the type of attacked one.
647 void evaluate_threats(const Position& pos, EvalInfo& ei) {
649 const Color Them = (Us == WHITE ? BLACK : WHITE);
652 Score bonus = make_score(0, 0);
654 // Enemy pieces not defended by a pawn and under our attack
655 Bitboard weakEnemies = pos.pieces_of_color(Them)
656 & ~ei.attackedBy[Them][PAWN]
657 & ei.attackedBy[Us][0];
661 // Add bonus according to type of attacked enemy pieces and to the
662 // type of attacking piece, from knights to queens. Kings are not
663 // considered because are already special handled in king evaluation.
664 for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
666 b = ei.attackedBy[Us][pt1] & weakEnemies;
668 for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
669 if (b & pos.pieces(pt2))
670 bonus += ThreatBonus[pt1][pt2];
672 ei.value += Sign[Us] * bonus;
676 // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
677 // pieces of a given color.
679 template<Color Us, bool HasPopCnt>
680 void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei) {
682 const Color Them = (Us == WHITE ? BLACK : WHITE);
684 // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
685 const Bitboard no_mob_area = ~(ei.attackedBy[Them][PAWN] | pos.pieces_of_color(Us));
687 evaluate_pieces<KNIGHT, Us, HasPopCnt>(pos, ei, no_mob_area);
688 evaluate_pieces<BISHOP, Us, HasPopCnt>(pos, ei, no_mob_area);
689 evaluate_pieces<ROOK, Us, HasPopCnt>(pos, ei, no_mob_area);
690 evaluate_pieces<QUEEN, Us, HasPopCnt>(pos, ei, no_mob_area);
692 // Sum up all attacked squares
693 ei.attackedBy[Us][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
694 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
695 | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
699 // evaluate_king<>() assigns bonuses and penalties to a king of a given color
701 template<Color Us, bool HasPopCnt>
702 void evaluate_king(const Position& pos, EvalInfo& ei) {
704 const Color Them = (Us == WHITE ? BLACK : WHITE);
706 Bitboard undefended, attackedByOthers, escapeSquares, occ, b, b2, safe;
709 int attackUnits, count, shelter = 0;
710 const Square s = pos.king_square(Us);
713 if (relative_rank(Us, s) <= RANK_4)
715 shelter = ei.pi->get_king_shelter(pos, Us, s);
716 ei.value += Sign[Us] * make_score(shelter, 0);
719 // King safety. This is quite complicated, and is almost certainly far
720 // from optimally tuned.
721 if ( pos.piece_count(Them, QUEEN) >= 1
722 && ei.kingAttackersCount[Them] >= 2
723 && pos.non_pawn_material(Them) >= QueenValueMidgame + RookValueMidgame
724 && ei.kingAdjacentZoneAttacksCount[Them])
726 // Is it the attackers turn to move?
727 sente = (Them == pos.side_to_move());
729 // Find the attacked squares around the king which has no defenders
730 // apart from the king itself
731 undefended = ei.attacked_by(Them) & ei.attacked_by(Us, KING);
732 undefended &= ~( ei.attacked_by(Us, PAWN) | ei.attacked_by(Us, KNIGHT)
733 | ei.attacked_by(Us, BISHOP) | ei.attacked_by(Us, ROOK)
734 | ei.attacked_by(Us, QUEEN));
736 // Initialize the 'attackUnits' variable, which is used later on as an
737 // index to the SafetyTable[] array. The initial value is based on the
738 // number and types of the attacking pieces, the number of attacked and
739 // undefended squares around the king, the square of the king, and the
740 // quality of the pawn shelter.
741 attackUnits = Min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
742 + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + count_1s_max_15<HasPopCnt>(undefended))
743 + InitKingDanger[relative_square(Us, s)]
746 // Analyse safe queen contact checks
747 b = undefended & ei.attacked_by(Them, QUEEN) & ~pos.pieces_of_color(Them);
750 attackedByOthers = ei.attacked_by(Them, PAWN) | ei.attacked_by(Them, KNIGHT)
751 | ei.attacked_by(Them, BISHOP) | ei.attacked_by(Them, ROOK);
753 b &= attackedByOthers;
755 // Squares attacked by the queen and supported by another enemy piece and
756 // not defended by other pieces but our king.
759 // The bitboard b now contains the squares available for safe queen
761 count = count_1s_max_15<HasPopCnt>(b);
762 attackUnits += QueenContactCheckBonus * count * (sente ? 2 : 1);
764 // Is there a mate threat?
765 if (QueenContactMates && !pos.is_check())
767 escapeSquares = pos.attacks_from<KING>(s) & ~pos.pieces_of_color(Us) & ~attackedByOthers;
768 occ = pos.occupied_squares();
771 to = pop_1st_bit(&b);
773 // Do we have escape squares from queen contact check attack ?
774 if (!(escapeSquares & ~queen_attacks_bb(to, occ & ClearMaskBB[s])))
776 // We have a mate, unless the queen is pinned or there
777 // is an X-ray attack through the queen.
778 for (int i = 0; i < pos.piece_count(Them, QUEEN); i++)
780 from = pos.piece_list(Them, QUEEN, i);
781 if ( bit_is_set(pos.attacks_from<QUEEN>(from), to)
782 && !bit_is_set(pos.pinned_pieces(Them), from)
783 && !(rook_attacks_bb(to, occ & ClearMaskBB[from]) & pos.pieces(ROOK, QUEEN, Us))
784 && !(bishop_attacks_bb(to, occ & ClearMaskBB[from]) & pos.pieces(BISHOP, QUEEN, Us)))
786 // Set the mate threat move
787 ei.mateThreat[Them] = make_move(from, to);
795 // Analyse safe distance checks
796 safe = ~(pos.pieces_of_color(Them) | ei.attacked_by(Us));
798 if (QueenCheckBonus > 0 || RookCheckBonus > 0)
800 b = pos.attacks_from<ROOK>(s) & safe;
803 b2 = b & ei.attacked_by(Them, QUEEN);
805 attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b2);
808 b2 = b & ei.attacked_by(Them, ROOK);
810 attackUnits += RookCheckBonus * count_1s_max_15<HasPopCnt>(b2);
812 if (QueenCheckBonus > 0 || BishopCheckBonus > 0)
814 b = pos.attacks_from<BISHOP>(s) & safe;
817 b2 = b & ei.attacked_by(Them, QUEEN);
819 attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b2);
822 b2 = b & ei.attacked_by(Them, BISHOP);
824 attackUnits += BishopCheckBonus * count_1s_max_15<HasPopCnt>(b2);
826 if (KnightCheckBonus > 0)
828 b = pos.attacks_from<KNIGHT>(s) & safe;
831 b2 = b & ei.attacked_by(Them, KNIGHT);
833 attackUnits += KnightCheckBonus * count_1s_max_15<HasPopCnt>(b2);
836 // Analyse discovered checks (only for non-pawns right now, consider
837 // adding pawns later).
838 if (DiscoveredCheckBonus)
840 b = pos.discovered_check_candidates(Them) & ~pos.pieces(PAWN);
842 attackUnits += DiscoveredCheckBonus * count_1s_max_15<HasPopCnt>(b) * (sente ? 2 : 1);
845 // Has a mate threat been found? We don't do anything here if the
846 // side with the mating move is the side to move, because in that
847 // case the mating side will get a huge bonus at the end of the main
848 // evaluation function instead.
849 if (ei.mateThreat[Them] != MOVE_NONE)
850 attackUnits += MateThreatBonus;
852 // Ensure that attackUnits is between 0 and 99, in order to avoid array
853 // out of bounds errors.
854 attackUnits = Min(99, Max(0, attackUnits));
856 // Finally, extract the king safety score from the SafetyTable[] array.
857 // Add the score to the evaluation, and also to ei.futilityMargin. The
858 // reason for adding the king safety score to the futility margin is
859 // that the king safety scores can sometimes be very big, and that
860 // capturing a single attacking piece can therefore result in a score
861 // change far bigger than the value of the captured piece.
862 Score v = apply_weight(make_score(SafetyTable[attackUnits], 0), WeightKingSafety[Us]);
864 ei.value -= Sign[Us] * v;
866 if (Us == pos.side_to_move())
867 ei.futilityMargin += mg_value(v);
872 // evaluate_passed_pawns() evaluates the passed pawns of the given color
875 void evaluate_passed_pawns_of_color(const Position& pos, int movesToGo[], Square pawnToGo[], EvalInfo& ei) {
877 const Color Them = (Us == WHITE ? BLACK : WHITE);
880 Square ourKingSq = pos.king_square(Us);
881 Square theirKingSq = pos.king_square(Them);
882 Bitboard b = ei.pi->passed_pawns() & pos.pieces(PAWN, Us);
886 Square s = pop_1st_bit(&b);
888 assert(pos.piece_on(s) == piece_of_color_and_type(Us, PAWN));
889 assert(pos.pawn_is_passed(Us, s));
891 int r = int(relative_rank(Us, s) - RANK_2);
892 int tr = Max(0, r * (r - 1));
894 // Base bonus based on rank
895 Value mbonus = Value(20 * tr);
896 Value ebonus = Value(10 + r * r * 10);
898 // Adjust bonus based on king proximity
901 Square blockSq = s + pawn_push(Us);
903 ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr);
904 ebonus -= Value(square_distance(ourKingSq, blockSq + pawn_push(Us)) * 1 * tr);
905 ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr);
907 // If the pawn is free to advance, increase bonus
908 if (pos.square_is_empty(blockSq))
910 // There are no enemy pawns in the pawn's path
911 b2 = squares_in_front_of(Us, s);
913 assert((b2 & pos.pieces(PAWN, Them)) == EmptyBoardBB);
915 // Squares attacked by us
916 b4 = b2 & ei.attacked_by(Us);
918 // Squares attacked or occupied by enemy pieces
919 b3 = b2 & (ei.attacked_by(Them) | pos.pieces_of_color(Them));
921 // If there is an enemy rook or queen attacking the pawn from behind,
922 // add all X-ray attacks by the rook or queen.
923 if ( (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them))
924 && (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from<QUEEN>(s)))
927 // Are any of the squares in the pawn's path attacked or occupied by the enemy?
928 if (b3 == EmptyBoardBB)
929 // No enemy attacks or pieces, huge bonus!
930 // Even bigger if we protect the pawn's path
931 ebonus += Value(tr * (b2 == b4 ? 17 : 15));
933 // OK, there are enemy attacks or pieces (but not pawns). Are those
934 // squares which are attacked by the enemy also attacked by us ?
935 // If yes, big bonus (but smaller than when there are no enemy attacks),
936 // if no, somewhat smaller bonus.
937 ebonus += Value(tr * ((b3 & b4) == b3 ? 13 : 8));
939 // At last, add a small bonus when there are no *friendly* pieces
940 // in the pawn's path.
941 if ((b2 & pos.pieces_of_color(Us)) == EmptyBoardBB)
946 // If the pawn is supported by a friendly pawn, increase bonus
947 b2 = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
949 ebonus += Value(r * 20);
950 else if (pos.attacks_from<PAWN>(s, Them) & b2)
951 ebonus += Value(r * 12);
953 // If the other side has only a king, check whether the pawn is
955 if (pos.non_pawn_material(Them) == Value(0))
960 qsq = relative_square(Us, make_square(square_file(s), RANK_8));
961 d = square_distance(s, qsq)
962 - square_distance(theirKingSq, qsq)
963 + (Us != pos.side_to_move());
967 int mtg = RANK_8 - relative_rank(Us, s);
968 int blockerCount = count_1s_max_15(squares_in_front_of(Us,s) & pos.occupied_squares());
971 if (d < 0 && (!movesToGo[Us] || movesToGo[Us] > mtg))
979 // Rook pawns are a special case: They are sometimes worse, and
980 // sometimes better than other passed pawns. It is difficult to find
981 // good rules for determining whether they are good or bad. For now,
982 // we try the following: Increase the value for rook pawns if the
983 // other side has no pieces apart from a knight, and decrease the
984 // value if the other side has a rook or queen.
985 if (square_file(s) == FILE_A || square_file(s) == FILE_H)
987 if ( pos.non_pawn_material(Them) <= KnightValueMidgame
988 && pos.piece_count(Them, KNIGHT) <= 1)
989 ebonus += ebonus / 4;
990 else if (pos.pieces(ROOK, QUEEN, Them))
991 ebonus -= ebonus / 4;
994 // Add the scores for this pawn to the middle game and endgame eval.
995 ei.value += Sign[Us] * apply_weight(make_score(mbonus, ebonus), WeightPassedPawns);
1001 // evaluate_passed_pawns() evaluates the passed pawns for both sides
1003 void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
1005 int movesToGo[2] = {0, 0};
1006 Square pawnToGo[2] = {SQ_NONE, SQ_NONE};
1008 // Evaluate pawns for each color
1009 evaluate_passed_pawns_of_color<WHITE>(pos, movesToGo, pawnToGo, ei);
1010 evaluate_passed_pawns_of_color<BLACK>(pos, movesToGo, pawnToGo, ei);
1012 // Neither side has an unstoppable passed pawn?
1013 if (!(movesToGo[WHITE] | movesToGo[BLACK]))
1016 // Does only one side have an unstoppable passed pawn?
1017 if (!movesToGo[WHITE] || !movesToGo[BLACK])
1019 Color winnerSide = movesToGo[WHITE] ? WHITE : BLACK;
1020 ei.value += make_score(0, Sign[winnerSide] * (UnstoppablePawnValue - Value(0x40 * movesToGo[winnerSide])));
1023 { // Both sides have unstoppable pawns! Try to find out who queens
1024 // first. We begin by transforming 'movesToGo' to the number of
1025 // plies until the pawn queens for both sides.
1026 movesToGo[WHITE] *= 2;
1027 movesToGo[BLACK] *= 2;
1028 movesToGo[pos.side_to_move()]--;
1030 Color winnerSide = movesToGo[WHITE] < movesToGo[BLACK] ? WHITE : BLACK;
1031 Color loserSide = opposite_color(winnerSide);
1033 // If one side queens at least three plies before the other, that side wins
1034 if (movesToGo[winnerSide] <= movesToGo[loserSide] - 3)
1035 ei.value += Sign[winnerSide] * make_score(0, UnstoppablePawnValue - Value(0x40 * (movesToGo[winnerSide]/2)));
1037 // If one side queens one ply before the other and checks the king or attacks
1038 // the undefended opponent's queening square, that side wins. To avoid cases
1039 // where the opponent's king could move somewhere before first pawn queens we
1040 // consider only free paths to queen for both pawns.
1041 else if ( !(squares_in_front_of(WHITE, pawnToGo[WHITE]) & pos.occupied_squares())
1042 && !(squares_in_front_of(BLACK, pawnToGo[BLACK]) & pos.occupied_squares()))
1044 assert(movesToGo[loserSide] - movesToGo[winnerSide] == 1);
1046 Square winnerQSq = relative_square(winnerSide, make_square(square_file(pawnToGo[winnerSide]), RANK_8));
1047 Square loserQSq = relative_square(loserSide, make_square(square_file(pawnToGo[loserSide]), RANK_8));
1049 Bitboard b = pos.occupied_squares();
1050 clear_bit(&b, pawnToGo[winnerSide]);
1051 clear_bit(&b, pawnToGo[loserSide]);
1052 b = queen_attacks_bb(winnerQSq, b);
1054 if ( (b & pos.pieces(KING, loserSide))
1055 ||(bit_is_set(b, loserQSq) && !bit_is_set(ei.attacked_by(loserSide), loserQSq)))
1056 ei.value += Sign[winnerSide] * make_score(0, UnstoppablePawnValue - Value(0x40 * (movesToGo[winnerSide]/2)));
1062 // evaluate_trapped_bishop_a7h7() determines whether a bishop on a7/h7
1063 // (a2/h2 for black) is trapped by enemy pawns, and assigns a penalty
1066 void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo &ei) {
1068 assert(square_is_ok(s));
1069 assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
1071 Square b6 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B6 : SQ_G6);
1072 Square b8 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B8 : SQ_G8);
1074 if ( pos.piece_on(b6) == piece_of_color_and_type(opposite_color(us), PAWN)
1075 && pos.see(s, b6) < 0
1076 && pos.see(s, b8) < 0)
1078 ei.value -= Sign[us] * TrappedBishopA7H7Penalty;
1083 // evaluate_trapped_bishop_a1h1() determines whether a bishop on a1/h1
1084 // (a8/h8 for black) is trapped by a friendly pawn on b2/g2 (b7/g7 for
1085 // black), and assigns a penalty if it is. This pattern can obviously
1086 // only occur in Chess960 games.
1088 void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei) {
1090 Piece pawn = piece_of_color_and_type(us, PAWN);
1094 assert(square_is_ok(s));
1095 assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
1097 if (square_file(s) == FILE_A)
1099 b2 = relative_square(us, SQ_B2);
1100 b3 = relative_square(us, SQ_B3);
1101 c3 = relative_square(us, SQ_C3);
1105 b2 = relative_square(us, SQ_G2);
1106 b3 = relative_square(us, SQ_G3);
1107 c3 = relative_square(us, SQ_F3);
1110 if (pos.piece_on(b2) == pawn)
1114 if (!pos.square_is_empty(b3))
1115 penalty = 2 * TrappedBishopA1H1Penalty;
1116 else if (pos.piece_on(c3) == pawn)
1117 penalty = TrappedBishopA1H1Penalty;
1119 penalty = TrappedBishopA1H1Penalty / 2;
1121 ei.value -= Sign[us] * penalty;
1126 // evaluate_space() computes the space evaluation for a given side. The
1127 // space evaluation is a simple bonus based on the number of safe squares
1128 // available for minor pieces on the central four files on ranks 2--4. Safe
1129 // squares one, two or three squares behind a friendly pawn are counted
1130 // twice. Finally, the space bonus is scaled by a weight taken from the
1131 // material hash table.
1132 template<Color Us, bool HasPopCnt>
1133 void evaluate_space(const Position& pos, EvalInfo& ei) {
1135 const Color Them = (Us == WHITE ? BLACK : WHITE);
1137 // Find the safe squares for our pieces inside the area defined by
1138 // SpaceMask[us]. A square is unsafe if it is attacked by an enemy
1139 // pawn, or if it is undefended and attacked by an enemy piece.
1141 Bitboard safeSquares = SpaceMask[Us]
1142 & ~pos.pieces(PAWN, Us)
1143 & ~ei.attacked_by(Them, PAWN)
1144 & ~(~ei.attacked_by(Us) & ei.attacked_by(Them));
1146 // Find all squares which are at most three squares behind some friendly
1148 Bitboard behindFriendlyPawns = pos.pieces(PAWN, Us);
1149 behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 8 : behindFriendlyPawns << 8);
1150 behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 16 : behindFriendlyPawns << 16);
1152 int space = count_1s_max_15<HasPopCnt>(safeSquares)
1153 + count_1s_max_15<HasPopCnt>(behindFriendlyPawns & safeSquares);
1155 ei.value += Sign[Us] * apply_weight(make_score(space * ei.mi->space_weight(), 0), WeightSpace);
1159 // apply_weight() applies an evaluation weight to a value trying to prevent overflow
1161 inline Score apply_weight(Score v, Score w) {
1162 return make_score((int(mg_value(v)) * mg_value(w)) / 0x100, (int(eg_value(v)) * eg_value(w)) / 0x100);
1166 // scale_by_game_phase() interpolates between a middle game and an endgame
1167 // score, based on game phase. It also scales the return value by a
1168 // ScaleFactor array.
1170 Value scale_by_game_phase(const Score& v, Phase ph, const ScaleFactor sf[]) {
1172 assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
1173 assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
1174 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1176 Value ev = apply_scale_factor(eg_value(v), sf[(eg_value(v) > Value(0) ? WHITE : BLACK)]);
1178 int result = (mg_value(v) * ph + ev * (128 - ph)) / 128;
1179 return Value(result & ~(GrainSize - 1));
1183 // weight_option() computes the value of an evaluation weight, by combining
1184 // two UCI-configurable weights (midgame and endgame) with an internal weight.
1186 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
1188 Score uciWeight = make_score(get_option_value_int(mgOpt), get_option_value_int(egOpt));
1190 // Convert to integer to prevent overflow
1191 int mg = mg_value(uciWeight);
1192 int eg = eg_value(uciWeight);
1194 mg = (mg * 0x100) / 100;
1195 eg = (eg * 0x100) / 100;
1196 mg = (mg * mg_value(internalWeight)) / 0x100;
1197 eg = (eg * eg_value(internalWeight)) / 0x100;
1198 return make_score(mg, eg);
1201 // init_safety() initizes the king safety evaluation, based on UCI
1202 // parameters. It is called from read_weights().
1204 void init_safety() {
1206 QueenContactCheckBonus = get_option_value_int("Queen Contact Check Bonus");
1207 QueenCheckBonus = get_option_value_int("Queen Check Bonus");
1208 RookCheckBonus = get_option_value_int("Rook Check Bonus");
1209 BishopCheckBonus = get_option_value_int("Bishop Check Bonus");
1210 KnightCheckBonus = get_option_value_int("Knight Check Bonus");
1211 DiscoveredCheckBonus = get_option_value_int("Discovered Check Bonus");
1212 MateThreatBonus = get_option_value_int("Mate Threat Bonus");
1214 int maxSlope = get_option_value_int("King Safety Max Slope");
1215 int peak = get_option_value_int("King Safety Max Value") * 256 / 100;
1216 double a = get_option_value_int("King Safety Coefficient") / 100.0;
1217 double b = get_option_value_int("King Safety X Intercept");
1218 bool quad = (get_option_value_string("King Safety Curve") == "Quadratic");
1219 bool linear = (get_option_value_string("King Safety Curve") == "Linear");
1221 for (int i = 0; i < 100; i++)
1224 SafetyTable[i] = Value(0);
1226 SafetyTable[i] = Value((int)(a * (i - b) * (i - b)));
1228 SafetyTable[i] = Value((int)(100 * a * (i - b)));
1231 for (int i = 0; i < 100; i++)
1233 if (SafetyTable[i+1] - SafetyTable[i] > maxSlope)
1234 for (int j = i + 1; j < 100; j++)
1235 SafetyTable[j] = SafetyTable[j-1] + Value(maxSlope);
1237 if (SafetyTable[i] > Value(peak))
1238 SafetyTable[i] = Value(peak);