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 int WeightMobilityMidgame, WeightMobilityEndgame;
50 int WeightPawnStructureMidgame, WeightPawnStructureEndgame;
51 int WeightPassedPawnsMidgame, WeightPassedPawnsEndgame;
52 int WeightKingSafety[2];
55 // Internal evaluation weights. These are applied on top of the evaluation
56 // weights read from UCI parameters. The purpose is to be able to change
57 // the evaluation weights while keeping the default values of the UCI
58 // parameters at 100, which looks prettier.
60 // Values modified by Joona Kiiski
61 const int WeightMobilityMidgameInternal = 248;
62 const int WeightMobilityEndgameInternal = 271;
63 const int WeightPawnStructureMidgameInternal = 233;
64 const int WeightPawnStructureEndgameInternal = 201;
65 const int WeightPassedPawnsMidgameInternal = 252;
66 const int WeightPassedPawnsEndgameInternal = 259;
67 const int WeightKingSafetyInternal = 247;
68 const int WeightKingOppSafetyInternal = 259;
69 const int WeightSpaceInternal = 46;
71 // Mobility and outposts bonus modified by Joona Kiiski
73 // Visually better to define tables constants
76 // Knight mobility bonus in middle game and endgame, indexed by the number
77 // of attacked squares not occupied by friendly piecess.
78 const Value MidgameKnightMobilityBonus[] = {
80 V(-38), V(-25),V(-12), V(0), V(12), V(25), V(31), V(38), V(38)
83 const Value EndgameKnightMobilityBonus[] = {
85 V(-33), V(-23),V(-13), V(-3), V(7), V(17), V(22), V(27), V(27)
88 // Bishop mobility bonus in middle game and endgame, indexed by the number
89 // of attacked squares not occupied by friendly pieces. X-ray attacks through
90 // queens are also included.
91 const Value MidgameBishopMobilityBonus[] = {
93 V(-25), V(-11), V(3), V(17), V(31), V(45), V(57), V(65),
94 // 8 9 10 11 12 13 14 15
95 V( 71), V( 74), V(76), V(78), V(79), V(80), V(81), V(81)
98 const Value EndgameBishopMobilityBonus[] = {
100 V(-30), V(-16), V(-2), V(12), V(26), V(40), V(52), V(60),
101 // 8 9 10 11 12 13 14 15
102 V( 65), V( 69), V(71), V(73), V(74), V(75), V(76), V(76)
105 // Rook mobility bonus in middle game and endgame, indexed by the number
106 // of attacked squares not occupied by friendly pieces. X-ray attacks through
107 // queens and rooks are also included.
108 const Value MidgameRookMobilityBonus[] = {
110 V(-20), V(-14), V(-8), V(-2), V(4), V(10), V(14), V(19),
111 // 8 9 10 11 12 13 14 15
112 V( 23), V( 26), V(27), V(28), V(29), V(30), V(31), V(32)
115 const Value EndgameRookMobilityBonus[] = {
117 V(-36), V(-19), V(-3), V(13), V(29), V(46), V(62), V(79),
118 // 8 9 10 11 12 13 14 15
119 V( 95), V(106),V(111),V(114),V(116),V(117),V(118),V(118)
122 // Queen mobility bonus in middle game and endgame, indexed by the number
123 // of attacked squares not occupied by friendly pieces.
124 const Value MidgameQueenMobilityBonus[] = {
126 V(-10), V(-8), V(-6), V(-3), V(-1), V( 1), V( 3), V( 5),
127 // 8 9 10 11 12 13 14 15
128 V( 8), V(10), V(12), V(15), V(16), V(17), V(18), V(20),
129 // 16 17 18 19 20 21 22 23
130 V( 20), V(20), V(20), V(20), V(20), V(20), V(20), V(20),
131 // 24 25 26 27 28 29 30 31
132 V( 20), V(20), V(20), V(20), V(20), V(20), V(20), V(20)
135 const Value EndgameQueenMobilityBonus[] = {
137 V(-18),V(-13), V(-7), V(-2), V( 3), V (8), V(13), V(19),
138 // 8 9 10 11 12 13 14 15
139 V( 23), V(27), V(32), V(34), V(35), V(35), V(35), V(35),
140 // 16 17 18 19 20 21 22 23
141 V( 35), V(35), V(35), V(35), V(35), V(35), V(35), V(35),
142 // 24 25 26 27 28 29 30 31
143 V( 35), V(35), V(35), V(35), V(35), V(35), V(35), V(35)
146 // Outpost bonuses for knights and bishops, indexed by square (from white's
148 const Value KnightOutpostBonus[64] = {
150 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 1
151 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 2
152 V(0), V(0), V(4), V(8), V(8), V(4), V(0), V(0), // 3
153 V(0), V(4),V(17),V(26),V(26),V(17), V(4), V(0), // 4
154 V(0), V(8),V(26),V(35),V(35),V(26), V(8), V(0), // 5
155 V(0), V(4),V(17),V(17),V(17),V(17), V(4), V(0), // 6
156 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 7
157 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8
160 const Value BishopOutpostBonus[64] = {
162 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 1
163 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 2
164 V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0), // 3
165 V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0), // 4
166 V(0),V(10),V(21),V(21),V(21),V(21),V(10), V(0), // 5
167 V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0), // 6
168 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 7
169 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8
172 // Bonus for unstoppable passed pawns
173 const Value UnstoppablePawnValue = Value(0x500);
175 // Rooks and queens on the 7th rank (modified by Joona Kiiski)
176 const Value MidgameRookOn7thBonus = Value(47);
177 const Value EndgameRookOn7thBonus = Value(98);
178 const Value MidgameQueenOn7thBonus = Value(27);
179 const Value EndgameQueenOn7thBonus = Value(54);
181 // Rooks on open files (modified by Joona Kiiski)
182 const Value RookOpenFileBonus = Value(43);
183 const Value RookHalfOpenFileBonus = Value(19);
185 // Penalty for rooks trapped inside a friendly king which has lost the
187 const Value TrappedRookPenalty = Value(180);
189 // Penalty for a bishop on a7/h7 (a2/h2 for black) which is trapped by
191 const Value TrappedBishopA7H7Penalty = Value(300);
193 // Bitboard masks for detecting trapped bishops on a7/h7 (a2/h2 for black)
194 const Bitboard MaskA7H7[2] = {
195 ((1ULL << SQ_A7) | (1ULL << SQ_H7)),
196 ((1ULL << SQ_A2) | (1ULL << SQ_H2))
199 // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
200 // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
201 // happen in Chess960 games.
202 const Value TrappedBishopA1H1Penalty = Value(100);
204 // Bitboard masks for detecting trapped bishops on a1/h1 (a8/h8 for black)
205 const Bitboard MaskA1H1[2] = {
206 ((1ULL << SQ_A1) | (1ULL << SQ_H1)),
207 ((1ULL << SQ_A8) | (1ULL << SQ_H8))
210 // The SpaceMask[color] contains the area of the board which is considered
211 // by the space evaluation. In the middle game, each side is given a bonus
212 // based on how many squares inside this area are safe and available for
213 // friendly minor pieces.
214 const Bitboard SpaceMask[2] = {
215 (1ULL<<SQ_C2) | (1ULL<<SQ_D2) | (1ULL<<SQ_E2) | (1ULL<<SQ_F2) |
216 (1ULL<<SQ_C3) | (1ULL<<SQ_D3) | (1ULL<<SQ_E3) | (1ULL<<SQ_F3) |
217 (1ULL<<SQ_C4) | (1ULL<<SQ_D4) | (1ULL<<SQ_E4) | (1ULL<<SQ_F4),
218 (1ULL<<SQ_C7) | (1ULL<<SQ_D7) | (1ULL<<SQ_E7) | (1ULL<<SQ_F7) |
219 (1ULL<<SQ_C6) | (1ULL<<SQ_D6) | (1ULL<<SQ_E6) | (1ULL<<SQ_F6) |
220 (1ULL<<SQ_C5) | (1ULL<<SQ_D5) | (1ULL<<SQ_E5) | (1ULL<<SQ_F5)
223 /// King safety constants and variables. The king safety scores are taken
224 /// from the array SafetyTable[]. Various little "meta-bonuses" measuring
225 /// the strength of the attack are added up into an integer, which is used
226 /// as an index to SafetyTable[].
228 // Attack weights for each piece type
229 const int QueenAttackWeight = 5;
230 const int RookAttackWeight = 3;
231 const int BishopAttackWeight = 2;
232 const int KnightAttackWeight = 2;
234 // Bonuses for safe checks, initialized from UCI options
235 int QueenContactCheckBonus, DiscoveredCheckBonus;
236 int QueenCheckBonus, RookCheckBonus, BishopCheckBonus, KnightCheckBonus;
238 // Scan for queen contact mates?
239 const bool QueenContactMates = true;
241 // Bonus for having a mate threat, initialized from UCI options
244 // InitKingDanger[] contains bonuses based on the position of the defending
246 const int InitKingDanger[64] = {
247 2, 0, 2, 5, 5, 2, 0, 2,
248 2, 2, 4, 8, 8, 4, 2, 2,
249 7, 10, 12, 12, 12, 12, 10, 7,
250 15, 15, 15, 15, 15, 15, 15, 15,
251 15, 15, 15, 15, 15, 15, 15, 15,
252 15, 15, 15, 15, 15, 15, 15, 15,
253 15, 15, 15, 15, 15, 15, 15, 15,
254 15, 15, 15, 15, 15, 15, 15, 15
257 // SafetyTable[] contains the actual king safety scores. It is initialized
259 Value SafetyTable[100];
261 // Pawn and material hash tables, indexed by the current thread id
262 PawnInfoTable* PawnTable[8] = {0, 0, 0, 0, 0, 0, 0, 0};
263 MaterialInfoTable* MaterialTable[8] = {0, 0, 0, 0, 0, 0, 0, 0};
265 // Sizes of pawn and material hash tables
266 const int PawnTableSize = 16384;
267 const int MaterialTableSize = 1024;
269 // Function prototypes
270 template<bool HasPopCnt>
271 Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID);
273 template<Color Us, bool HasPopCnt>
274 void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei);
276 template<Color Us, bool HasPopCnt>
277 void evaluate_king(const Position& pos, EvalInfo& ei);
279 template<Color Us, bool HasPopCnt>
280 void evaluate_space(const Position& pos, EvalInfo& ei);
282 void evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
283 void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo& ei);
284 void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei);
285 inline Value apply_weight(Value v, int w);
286 Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]);
287 int weight_option(const std::string& opt, int weight);
296 /// evaluate() is the main evaluation function. It always computes two
297 /// values, an endgame score and a middle game score, and interpolates
298 /// between them based on the remaining material.
299 Value evaluate(const Position& pos, EvalInfo& ei, int threadID) {
301 return CpuHasPOPCNT ? do_evaluate<true>(pos, ei, threadID)
302 : do_evaluate<false>(pos, ei, threadID);
307 template<bool HasPopCnt>
308 Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID) {
311 assert(threadID >= 0 && threadID < THREAD_MAX);
313 memset(&ei, 0, sizeof(EvalInfo));
315 // Initialize by reading the incrementally updated scores included in the
316 // position object (material + piece square tables)
317 ei.mgValue = pos.mg_value();
318 ei.egValue = pos.eg_value();
320 // Probe the material hash table
321 ei.mi = MaterialTable[threadID]->get_material_info(pos);
322 ei.mgValue += ei.mi->material_value();
323 ei.egValue += ei.mi->material_value();
325 // If we have a specialized evaluation function for the current material
326 // configuration, call it and return
327 if (ei.mi->specialized_eval_exists())
328 return ei.mi->evaluate(pos);
330 // After get_material_info() call that modifies them
331 ScaleFactor factor[2];
332 factor[WHITE] = ei.mi->scale_factor(pos, WHITE);
333 factor[BLACK] = ei.mi->scale_factor(pos, BLACK);
335 // Probe the pawn hash table
336 ei.pi = PawnTable[threadID]->get_pawn_info(pos);
337 ei.mgValue += apply_weight(ei.pi->mg_value(), WeightPawnStructureMidgame);
338 ei.egValue += apply_weight(ei.pi->eg_value(), WeightPawnStructureEndgame);
340 // Initialize king attack bitboards and king attack zones for both sides
341 ei.attackedBy[WHITE][KING] = pos.attacks_from<KING>(pos.king_square(WHITE));
342 ei.attackedBy[BLACK][KING] = pos.attacks_from<KING>(pos.king_square(BLACK));
343 ei.kingZone[WHITE] = ei.attackedBy[BLACK][KING] | (ei.attackedBy[BLACK][KING] >> 8);
344 ei.kingZone[BLACK] = ei.attackedBy[WHITE][KING] | (ei.attackedBy[WHITE][KING] << 8);
346 // Initialize pawn attack bitboards for both sides
347 ei.attackedBy[WHITE][PAWN] = ei.pi->pawn_attacks(WHITE);
348 ei.attackedBy[BLACK][PAWN] = ei.pi->pawn_attacks(BLACK);
349 Bitboard b1 = ei.attackedBy[WHITE][PAWN] & ei.attackedBy[BLACK][KING];
350 Bitboard b2 = ei.attackedBy[BLACK][PAWN] & ei.attackedBy[WHITE][KING];
352 ei.kingAttackersCount[WHITE] = count_1s_max_15<HasPopCnt>(b1)/2;
355 ei.kingAttackersCount[BLACK] = count_1s_max_15<HasPopCnt>(b2)/2;
358 evaluate_pieces_of_color<WHITE, HasPopCnt>(pos, ei);
359 evaluate_pieces_of_color<BLACK, HasPopCnt>(pos, ei);
361 // Kings. Kings are evaluated after all other pieces for both sides,
362 // because we need complete attack information for all pieces when computing
363 // the king safety evaluation.
364 evaluate_king<WHITE, HasPopCnt>(pos, ei);
365 evaluate_king<BLACK, HasPopCnt>(pos, ei);
367 // Evaluate passed pawns. We evaluate passed pawns for both sides at once,
368 // because we need to know which side promotes first in positions where
369 // both sides have an unstoppable passed pawn.
370 if (ei.pi->passed_pawns())
371 evaluate_passed_pawns(pos, ei);
373 Phase phase = pos.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.mgValue += ei.pi->queenside_storm_value(WHITE)
383 - ei.pi->kingside_storm_value(BLACK);
385 else if ( square_file(pos.king_square(WHITE)) <= FILE_D
386 && square_file(pos.king_square(BLACK)) >= FILE_E)
388 ei.mgValue += ei.pi->kingside_storm_value(WHITE)
389 - ei.pi->queenside_storm_value(BLACK);
391 // Evaluate space for both sides
392 if (ei.mi->space_weight() > 0)
394 evaluate_space<WHITE, HasPopCnt>(pos, ei);
395 evaluate_space<BLACK, HasPopCnt>(pos, ei);
400 ei.mgValue += apply_weight(ei.mgMobility, WeightMobilityMidgame);
401 ei.egValue += apply_weight(ei.egMobility, WeightMobilityEndgame);
403 // If we don't already have an unusual scale factor, check for opposite
404 // colored bishop endgames, and use a lower scale for those
405 if ( phase < PHASE_MIDGAME
406 && pos.opposite_colored_bishops()
407 && ( (factor[WHITE] == SCALE_FACTOR_NORMAL && ei.egValue > Value(0))
408 || (factor[BLACK] == SCALE_FACTOR_NORMAL && ei.egValue < Value(0))))
412 // Only the two bishops ?
413 if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
414 && pos.non_pawn_material(BLACK) == BishopValueMidgame)
416 // Check for KBP vs KB with only a single pawn that is almost
417 // certainly a draw or at least two pawns.
418 bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
419 sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
422 // Endgame with opposite-colored bishops, but also other pieces. Still
423 // a bit drawish, but not as drawish as with only the two bishops.
424 sf = ScaleFactor(50);
426 if (factor[WHITE] == SCALE_FACTOR_NORMAL)
428 if (factor[BLACK] == SCALE_FACTOR_NORMAL)
432 // Interpolate between the middle game and the endgame score
433 Color stm = pos.side_to_move();
435 Value v = Sign[stm] * scale_by_game_phase(ei.mgValue, ei.egValue, phase, factor);
437 return (ei.mateThreat[stm] == MOVE_NONE ? v : 8 * QueenValueMidgame - v);
442 /// quick_evaluate() does a very approximate evaluation of the current position.
443 /// It currently considers only material and piece square table scores. Perhaps
444 /// we should add scores from the pawn and material hash tables?
446 Value quick_evaluate(const Position &pos) {
451 ScaleFactor sf[2] = {SCALE_FACTOR_NORMAL, SCALE_FACTOR_NORMAL};
453 Value mgv = pos.mg_value();
454 Value egv = pos.eg_value();
455 Phase ph = pos.game_phase();
456 Color stm = pos.side_to_move();
458 return Sign[stm] * scale_by_game_phase(mgv, egv, ph, sf);
462 /// init_eval() initializes various tables used by the evaluation function
464 void init_eval(int threads) {
466 assert(threads <= THREAD_MAX);
468 for (int i = 0; i < THREAD_MAX; i++)
473 delete MaterialTable[i];
475 MaterialTable[i] = NULL;
479 PawnTable[i] = new PawnInfoTable(PawnTableSize);
480 if (!MaterialTable[i])
481 MaterialTable[i] = new MaterialInfoTable(MaterialTableSize);
486 /// quit_eval() releases heap-allocated memory at program termination
490 for (int i = 0; i < THREAD_MAX; i++)
493 delete MaterialTable[i];
495 MaterialTable[i] = NULL;
500 /// read_weights() reads evaluation weights from the corresponding UCI parameters
502 void read_weights(Color us) {
504 Color them = opposite_color(us);
506 WeightMobilityMidgame = weight_option("Mobility (Middle Game)", WeightMobilityMidgameInternal);
507 WeightMobilityEndgame = weight_option("Mobility (Endgame)", WeightMobilityEndgameInternal);
508 WeightPawnStructureMidgame = weight_option("Pawn Structure (Middle Game)", WeightPawnStructureMidgameInternal);
509 WeightPawnStructureEndgame = weight_option("Pawn Structure (Endgame)", WeightPawnStructureEndgameInternal);
510 WeightPassedPawnsMidgame = weight_option("Passed Pawns (Middle Game)", WeightPassedPawnsMidgameInternal);
511 WeightPassedPawnsEndgame = weight_option("Passed Pawns (Endgame)", WeightPassedPawnsEndgameInternal);
512 WeightSpace = weight_option("Space", WeightSpaceInternal);
513 WeightKingSafety[us] = weight_option("Cowardice", WeightKingSafetyInternal);
514 WeightKingSafety[them] = weight_option("Aggressiveness", WeightKingOppSafetyInternal);
516 // If running in analysis mode, make sure we use symmetrical king safety. We do this
517 // by replacing both WeightKingSafety[us] and WeightKingSafety[them] by their average.
518 if (get_option_value_bool("UCI_AnalyseMode"))
520 WeightKingSafety[us] = (WeightKingSafety[us] + WeightKingSafety[them]) / 2;
521 WeightKingSafety[them] = WeightKingSafety[us];
529 // evaluate_mobility() computes mobility and attacks for every piece
531 template<PieceType Piece, Color Us, bool HasPopCnt>
532 int evaluate_mobility(const Position& pos, Bitboard b, EvalInfo& ei) {
534 const Color Them = (Us == WHITE ? BLACK : WHITE);
535 static const int AttackWeight[] = { 0, 0, KnightAttackWeight, BishopAttackWeight, RookAttackWeight, QueenAttackWeight };
536 static const Value* MgBonus[] = { 0, 0, MidgameKnightMobilityBonus, MidgameBishopMobilityBonus, MidgameRookMobilityBonus, MidgameQueenMobilityBonus };
537 static const Value* EgBonus[] = { 0, 0, EndgameKnightMobilityBonus, EndgameBishopMobilityBonus, EndgameRookMobilityBonus, EndgameQueenMobilityBonus };
538 static const int lastIndex[] = { 0, 0, 8, 15, 15, 31 };
540 // Update attack info
541 ei.attackedBy[Us][Piece] |= b;
544 if (b & ei.kingZone[Us])
546 ei.kingAttackersCount[Us]++;
547 ei.kingAttackersWeight[Us] += AttackWeight[Piece];
548 Bitboard bb = (b & ei.attackedBy[Them][KING]);
550 ei.kingAdjacentZoneAttacksCount[Us] += count_1s_max_15<HasPopCnt>(bb);
553 // Remove squares protected by enemy pawns or occupied by our pieces
554 b &= ~(ei.attackedBy[Them][PAWN] | pos.pieces_of_color(Us));
556 // The squares occupied by enemy pieces (not defended by pawns) will be
557 // counted two times instead of one. The shift (almost) guarantees that
558 // intersection of the shifted value with b is zero so that after or-ing
559 // the count of 1s bits is increased by the number of affected squares.
560 b |= Us == WHITE ? ((b & pos.pieces_of_color(Them)) >> 1)
561 : ((b & pos.pieces_of_color(Them)) << 1);
564 int mob = (Piece != QUEEN ? count_1s_max_15<HasPopCnt>(b)
565 : count_1s<HasPopCnt>(b));
567 if (mob > lastIndex[Piece])
568 mob = lastIndex[Piece];
570 ei.mgMobility += Sign[Us] * MgBonus[Piece][mob];
571 ei.egMobility += Sign[Us] * EgBonus[Piece][mob];
576 // evaluate_outposts() evaluates bishop and knight outposts squares
578 template<PieceType Piece, Color Us>
579 void evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
581 const Color Them = (Us == WHITE ? BLACK : WHITE);
583 // Initial bonus based on square
584 Value bonus = (Piece == BISHOP ? BishopOutpostBonus[relative_square(Us, s)]
585 : KnightOutpostBonus[relative_square(Us, s)]);
587 // Increase bonus if supported by pawn, especially if the opponent has
588 // no minor piece which can exchange the outpost piece
589 if (bonus && (pos.attacks_from<PAWN>(s, Them) & pos.pieces(PAWN, Us)))
591 if ( pos.pieces(KNIGHT, Them) == EmptyBoardBB
592 && (SquaresByColorBB[square_color(s)] & pos.pieces(BISHOP, Them)) == EmptyBoardBB)
593 bonus += bonus + bonus / 2;
597 ei.mgValue += Sign[Us] * bonus;
598 ei.egValue += Sign[Us] * bonus;
602 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
604 template<PieceType Piece, Color Us, bool HasPopCnt>
605 void evaluate_pieces(const Position& pos, EvalInfo& ei) {
612 const Color Them = (Us == WHITE ? BLACK : WHITE);
613 const Square* ptr = pos.piece_list_begin(Us, Piece);
615 while ((s = *ptr++) != SQ_NONE)
617 if (Piece == KNIGHT || Piece == QUEEN)
618 b = pos.attacks_from<Piece>(s);
619 else if (Piece == BISHOP)
620 b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
621 else if (Piece == ROOK)
622 b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
626 // Attacks and mobility
627 mob = evaluate_mobility<Piece, Us, HasPopCnt>(pos, b, ei);
629 // Bishop and knight outposts squares
630 if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Them))
631 evaluate_outposts<Piece, Us>(pos, ei, s);
633 // Special patterns: trapped bishops on a7/h7/a2/h2
634 // and trapped bishops on a1/h1/a8/h8 in Chess960.
637 if (bit_is_set(MaskA7H7[Us], s))
638 evaluate_trapped_bishop_a7h7(pos, s, Us, ei);
640 if (Chess960 && bit_is_set(MaskA1H1[Us], s))
641 evaluate_trapped_bishop_a1h1(pos, s, Us, ei);
644 if (Piece == ROOK || Piece == QUEEN)
646 // Queen or rook on 7th rank
647 if ( relative_rank(Us, s) == RANK_7
648 && relative_rank(Us, pos.king_square(Them)) == RANK_8)
650 ei.mgValue += Sign[Us] * (Piece == ROOK ? MidgameRookOn7thBonus : MidgameQueenOn7thBonus);
651 ei.egValue += Sign[Us] * (Piece == ROOK ? EndgameRookOn7thBonus : EndgameQueenOn7thBonus);
655 // Special extra evaluation for rooks
658 // Open and half-open files
660 if (ei.pi->file_is_half_open(Us, f))
662 if (ei.pi->file_is_half_open(Them, f))
664 ei.mgValue += Sign[Us] * RookOpenFileBonus;
665 ei.egValue += Sign[Us] * RookOpenFileBonus;
669 ei.mgValue += Sign[Us] * RookHalfOpenFileBonus;
670 ei.egValue += Sign[Us] * RookHalfOpenFileBonus;
674 // Penalize rooks which are trapped inside a king. Penalize more if
675 // king has lost right to castle.
676 if (mob > 6 || ei.pi->file_is_half_open(Us, f))
679 ksq = pos.king_square(Us);
681 if ( square_file(ksq) >= FILE_E
682 && square_file(s) > square_file(ksq)
683 && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
685 // Is there a half-open file between the king and the edge of the board?
686 if (!ei.pi->has_open_file_to_right(Us, square_file(ksq)))
687 ei.mgValue -= pos.can_castle(Us)? Sign[Us] * ((TrappedRookPenalty - mob * 16) / 2)
688 : Sign[Us] * (TrappedRookPenalty - mob * 16);
690 else if ( square_file(ksq) <= FILE_D
691 && square_file(s) < square_file(ksq)
692 && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
694 // Is there a half-open file between the king and the edge of the board?
695 if (!ei.pi->has_open_file_to_left(Us, square_file(ksq)))
696 ei.mgValue -= pos.can_castle(Us)? Sign[Us] * ((TrappedRookPenalty - mob * 16) / 2)
697 : Sign[Us] * (TrappedRookPenalty - mob * 16);
704 // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
705 // pieces of a given color.
707 template<Color Us, bool HasPopCnt>
708 void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei) {
710 evaluate_pieces<KNIGHT, Us, HasPopCnt>(pos, ei);
711 evaluate_pieces<BISHOP, Us, HasPopCnt>(pos, ei);
712 evaluate_pieces<ROOK, Us, HasPopCnt>(pos, ei);
713 evaluate_pieces<QUEEN, Us, HasPopCnt>(pos, ei);
715 // Sum up all attacked squares
716 ei.attackedBy[Us][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
717 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
718 | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
722 // evaluate_king<>() assigns bonuses and penalties to a king of a given color
724 template<Color Us, bool HasPopCnt>
725 void evaluate_king(const Position& pos, EvalInfo& ei) {
727 const Color Them = (Us == WHITE ? BLACK : WHITE);
728 const Square s = pos.king_square(Us);
732 if (relative_rank(Us, s) <= RANK_4)
734 shelter = ei.pi->get_king_shelter(pos, Us, s);
735 ei.mgValue += Sign[Us] * Value(shelter);
738 // King safety. This is quite complicated, and is almost certainly far
739 // from optimally tuned.
740 if ( pos.piece_count(Them, QUEEN) >= 1
741 && ei.kingAttackersCount[Them] >= 2
742 && pos.non_pawn_material(Them) >= QueenValueMidgame + RookValueMidgame
743 && ei.kingAdjacentZoneAttacksCount[Them])
745 // Is it the attackers turn to move?
746 bool sente = (Them == pos.side_to_move());
748 // Find the attacked squares around the king which has no defenders
749 // apart from the king itself
750 Bitboard undefended =
751 ei.attacked_by(Them) & ~ei.attacked_by(Us, PAWN)
752 & ~ei.attacked_by(Us, KNIGHT) & ~ei.attacked_by(Us, BISHOP)
753 & ~ei.attacked_by(Us, ROOK) & ~ei.attacked_by(Us, QUEEN)
754 & ei.attacked_by(Us, KING);
756 Bitboard occ = pos.occupied_squares(), b, b2;
758 // Initialize the 'attackUnits' variable, which is used later on as an
759 // index to the SafetyTable[] array. The initial value is based on the
760 // number and types of the attacking pieces, the number of attacked and
761 // undefended squares around the king, the square of the king, and the
762 // quality of the pawn shelter.
764 Min((ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2, 25)
765 + (ei.kingAdjacentZoneAttacksCount[Them] + count_1s_max_15<HasPopCnt>(undefended)) * 3
766 + InitKingDanger[relative_square(Us, s)] - (shelter >> 5);
768 // Analyse safe queen contact checks
769 b = undefended & ei.attacked_by(Them, QUEEN) & ~pos.pieces_of_color(Them);
772 Bitboard attackedByOthers =
773 ei.attacked_by(Them, PAWN) | ei.attacked_by(Them, KNIGHT)
774 | ei.attacked_by(Them, BISHOP) | ei.attacked_by(Them, ROOK);
776 b &= attackedByOthers;
779 // The bitboard b now contains the squares available for safe queen
781 int count = count_1s_max_15<HasPopCnt>(b);
782 attackUnits += QueenContactCheckBonus * count * (sente ? 2 : 1);
784 // Is there a mate threat?
785 if (QueenContactMates && !pos.is_check())
787 Bitboard escapeSquares =
788 pos.attacks_from<KING>(s) & ~pos.pieces_of_color(Us) & ~attackedByOthers;
792 Square from, to = pop_1st_bit(&b);
793 if (!(escapeSquares & ~queen_attacks_bb(to, occ & ClearMaskBB[s])))
795 // We have a mate, unless the queen is pinned or there
796 // is an X-ray attack through the queen.
797 for (int i = 0; i < pos.piece_count(Them, QUEEN); i++)
799 from = pos.piece_list(Them, QUEEN, i);
800 if ( bit_is_set(pos.attacks_from<QUEEN>(from), to)
801 && !bit_is_set(pos.pinned_pieces(Them), from)
802 && !(rook_attacks_bb(to, occ & ClearMaskBB[from]) & pos.pieces(ROOK, QUEEN, Us))
803 && !(bishop_attacks_bb(to, occ & ClearMaskBB[from]) & pos.pieces(BISHOP, QUEEN, Us)))
805 ei.mateThreat[Them] = make_move(from, to);
813 // Analyse safe distance checks
814 if (QueenCheckBonus > 0 || RookCheckBonus > 0)
816 b = pos.attacks_from<ROOK>(s) & ~pos.pieces_of_color(Them) & ~ei.attacked_by(Us);
819 b2 = b & ei.attacked_by(Them, QUEEN);
821 attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b2);
824 b2 = b & ei.attacked_by(Them, ROOK);
826 attackUnits += RookCheckBonus * count_1s_max_15<HasPopCnt>(b2);
828 if (QueenCheckBonus > 0 || BishopCheckBonus > 0)
830 b = pos.attacks_from<BISHOP>(s) & ~pos.pieces_of_color(Them) & ~ei.attacked_by(Us);
833 b2 = b & ei.attacked_by(Them, QUEEN);
835 attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b2);
838 b2 = b & ei.attacked_by(Them, BISHOP);
840 attackUnits += BishopCheckBonus * count_1s_max_15<HasPopCnt>(b2);
842 if (KnightCheckBonus > 0)
844 b = pos.attacks_from<KNIGHT>(s) & ~pos.pieces_of_color(Them) & ~ei.attacked_by(Us);
847 b2 = b & ei.attacked_by(Them, KNIGHT);
849 attackUnits += KnightCheckBonus * count_1s_max_15<HasPopCnt>(b2);
852 // Analyse discovered checks (only for non-pawns right now, consider
853 // adding pawns later).
854 if (DiscoveredCheckBonus)
856 b = pos.discovered_check_candidates(Them) & ~pos.pieces(PAWN);
858 attackUnits += DiscoveredCheckBonus * count_1s_max_15<HasPopCnt>(b) * (sente ? 2 : 1);
861 // Has a mate threat been found? We don't do anything here if the
862 // side with the mating move is the side to move, because in that
863 // case the mating side will get a huge bonus at the end of the main
864 // evaluation function instead.
865 if (ei.mateThreat[Them] != MOVE_NONE)
866 attackUnits += MateThreatBonus;
868 // Ensure that attackUnits is between 0 and 99, in order to avoid array
869 // out of bounds errors:
873 if (attackUnits >= 100)
876 // Finally, extract the king safety score from the SafetyTable[] array.
877 // Add the score to the evaluation, and also to ei.futilityMargin. The
878 // reason for adding the king safety score to the futility margin is
879 // that the king safety scores can sometimes be very big, and that
880 // capturing a single attacking piece can therefore result in a score
881 // change far bigger than the value of the captured piece.
882 Value v = apply_weight(SafetyTable[attackUnits], WeightKingSafety[Us]);
884 ei.mgValue -= Sign[Us] * v;
886 if (Us == pos.side_to_move())
887 ei.futilityMargin += v;
892 // evaluate_passed_pawns() evaluates the passed pawns of the given color
895 void evaluate_passed_pawns_of_color(const Position& pos, int movesToGo[], EvalInfo& ei) {
897 const Color Them = (Us == WHITE ? BLACK : WHITE);
900 Square ourKingSq = pos.king_square(Us);
901 Square theirKingSq = pos.king_square(Them);
902 Bitboard b = ei.pi->passed_pawns() & pos.pieces(PAWN, Us);
906 Square s = pop_1st_bit(&b);
908 assert(pos.piece_on(s) == piece_of_color_and_type(Us, PAWN));
909 assert(pos.pawn_is_passed(Us, s));
911 int r = int(relative_rank(Us, s) - RANK_2);
912 int tr = Max(0, r * (r - 1));
914 // Base bonus based on rank
915 Value mbonus = Value(20 * tr);
916 Value ebonus = Value(10 + r * r * 10);
918 // Adjust bonus based on king proximity
921 Square blockSq = s + pawn_push(Us);
923 ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr);
924 ebonus -= Value(square_distance(ourKingSq, blockSq + pawn_push(Us)) * 1 * tr);
925 ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr);
927 // If the pawn is free to advance, increase bonus
928 if (pos.square_is_empty(blockSq))
930 // There are no enemy pawns in the pawn's path
931 b2 = squares_in_front_of(Us, s);
933 assert((b2 & pos.pieces(PAWN, Them)) == EmptyBoardBB);
935 // Squares attacked by us
936 b4 = b2 & ei.attacked_by(Us);
938 // Squares attacked or occupied by enemy pieces
939 b3 = b2 & (ei.attacked_by(Them) | pos.pieces_of_color(Them));
941 // If there is an enemy rook or queen attacking the pawn from behind,
942 // add all X-ray attacks by the rook or queen.
943 if ( bit_is_set(ei.attacked_by(Them, ROOK) | ei.attacked_by(Them, QUEEN), s)
944 && (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them)))
947 // Are any of the squares in the pawn's path attacked or occupied by the enemy?
948 if (b3 == EmptyBoardBB)
949 // No enemy attacks or pieces, huge bonus!
950 // Even bigger if we protect the pawn's path
951 ebonus += Value(tr * (b2 == b4 ? 17 : 15));
953 // OK, there are enemy attacks or pieces (but not pawns). Are those
954 // squares which are attacked by the enemy also attacked by us ?
955 // If yes, big bonus (but smaller than when there are no enemy attacks),
956 // if no, somewhat smaller bonus.
957 ebonus += Value(tr * ((b3 & b4) == b3 ? 13 : 8));
959 // At last, add a small bonus when there are no *friendly* pieces
960 // in the pawn's path.
961 if ((b2 & pos.pieces_of_color(Us)) == EmptyBoardBB)
966 // If the pawn is supported by a friendly pawn, increase bonus
967 b2 = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
969 ebonus += Value(r * 20);
970 else if (pos.attacks_from<PAWN>(s, Them) & b2)
971 ebonus += Value(r * 12);
973 // If the other side has only a king, check whether the pawn is
975 if (pos.non_pawn_material(Them) == Value(0))
980 qsq = relative_square(Us, make_square(square_file(s), RANK_8));
981 d = square_distance(s, qsq)
982 - square_distance(theirKingSq, qsq)
983 + (Us != pos.side_to_move());
987 int mtg = RANK_8 - relative_rank(Us, s);
988 int blockerCount = count_1s_max_15(squares_in_front_of(Us,s) & pos.occupied_squares());
992 movesToGo[Us] = movesToGo[Us] ? Min(movesToGo[Us], mtg) : mtg;
996 // Rook pawns are a special case: They are sometimes worse, and
997 // sometimes better than other passed pawns. It is difficult to find
998 // good rules for determining whether they are good or bad. For now,
999 // we try the following: Increase the value for rook pawns if the
1000 // other side has no pieces apart from a knight, and decrease the
1001 // value if the other side has a rook or queen.
1002 if (square_file(s) == FILE_A || square_file(s) == FILE_H)
1004 if ( pos.non_pawn_material(Them) <= KnightValueMidgame
1005 && pos.piece_count(Them, KNIGHT) <= 1)
1006 ebonus += ebonus / 4;
1007 else if (pos.pieces(ROOK, QUEEN, Them))
1008 ebonus -= ebonus / 4;
1011 // Add the scores for this pawn to the middle game and endgame eval.
1012 ei.mgValue += apply_weight(Sign[Us] * mbonus, WeightPassedPawnsMidgame);
1013 ei.egValue += apply_weight(Sign[Us] * ebonus, WeightPassedPawnsEndgame);
1019 // evaluate_passed_pawns() evaluates the passed pawns for both sides
1021 void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
1023 int movesToGo[2] = {0, 0};
1025 // Evaluate pawns for each color
1026 evaluate_passed_pawns_of_color<WHITE>(pos, movesToGo, ei);
1027 evaluate_passed_pawns_of_color<BLACK>(pos, movesToGo, ei);
1029 // Does either side have an unstoppable passed pawn?
1030 if (movesToGo[WHITE] && !movesToGo[BLACK])
1031 ei.egValue += UnstoppablePawnValue - Value(0x40 * movesToGo[WHITE]);
1032 else if (movesToGo[BLACK] && !movesToGo[WHITE])
1033 ei.egValue -= UnstoppablePawnValue - Value(0x40 * movesToGo[BLACK]);
1034 else if (movesToGo[BLACK] && movesToGo[WHITE])
1036 // Both sides have unstoppable pawns! Try to find out who queens
1037 // first. We begin by transforming 'movesToGo' to the number of
1038 // plies until the pawn queens for both sides.
1039 movesToGo[WHITE] *= 2;
1040 movesToGo[BLACK] *= 2;
1041 movesToGo[pos.side_to_move()]--;
1043 // If one side queens at least three plies before the other, that
1045 if (movesToGo[WHITE] <= movesToGo[BLACK] - 3)
1046 ei.egValue += UnstoppablePawnValue - Value(0x40 * (movesToGo[WHITE]/2));
1047 else if (movesToGo[BLACK] <= movesToGo[WHITE] - 3)
1048 ei.egValue -= UnstoppablePawnValue - Value(0x40 * (movesToGo[BLACK]/2));
1050 // We could also add some rules about the situation when one side
1051 // queens exactly one ply before the other: Does the first queen
1052 // check the opponent's king, or attack the opponent's queening square?
1053 // This is slightly tricky to get right, because it is possible that
1054 // the opponent's king has moved somewhere before the first pawn queens.
1059 // evaluate_trapped_bishop_a7h7() determines whether a bishop on a7/h7
1060 // (a2/h2 for black) is trapped by enemy pawns, and assigns a penalty
1063 void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo &ei) {
1065 assert(square_is_ok(s));
1066 assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
1068 Square b6 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B6 : SQ_G6);
1069 Square b8 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B8 : SQ_G8);
1071 if ( pos.piece_on(b6) == piece_of_color_and_type(opposite_color(us), PAWN)
1072 && pos.see(s, b6) < 0
1073 && pos.see(s, b8) < 0)
1075 ei.mgValue -= Sign[us] * TrappedBishopA7H7Penalty;
1076 ei.egValue -= Sign[us] * TrappedBishopA7H7Penalty;
1081 // evaluate_trapped_bishop_a1h1() determines whether a bishop on a1/h1
1082 // (a8/h8 for black) is trapped by a friendly pawn on b2/g2 (b7/g7 for
1083 // black), and assigns a penalty if it is. This pattern can obviously
1084 // only occur in Chess960 games.
1086 void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei) {
1088 Piece pawn = piece_of_color_and_type(us, PAWN);
1092 assert(square_is_ok(s));
1093 assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
1095 if (square_file(s) == FILE_A)
1097 b2 = relative_square(us, SQ_B2);
1098 b3 = relative_square(us, SQ_B3);
1099 c3 = relative_square(us, SQ_C3);
1103 b2 = relative_square(us, SQ_G2);
1104 b3 = relative_square(us, SQ_G3);
1105 c3 = relative_square(us, SQ_F3);
1108 if (pos.piece_on(b2) == pawn)
1112 if (!pos.square_is_empty(b3))
1113 penalty = 2*TrappedBishopA1H1Penalty;
1114 else if (pos.piece_on(c3) == pawn)
1115 penalty = TrappedBishopA1H1Penalty;
1117 penalty = TrappedBishopA1H1Penalty / 2;
1119 ei.mgValue -= Sign[us] * penalty;
1120 ei.egValue -= Sign[us] * penalty;
1125 // evaluate_space() computes the space evaluation for a given side. The
1126 // space evaluation is a simple bonus based on the number of safe squares
1127 // available for minor pieces on the central four files on ranks 2--4. Safe
1128 // squares one, two or three squares behind a friendly pawn are counted
1129 // twice. Finally, the space bonus is scaled by a weight taken from the
1130 // material hash table.
1131 template<Color Us, bool HasPopCnt>
1132 void evaluate_space(const Position& pos, EvalInfo& ei) {
1134 const Color Them = (Us == WHITE ? BLACK : WHITE);
1136 // Find the safe squares for our pieces inside the area defined by
1137 // SpaceMask[us]. A square is unsafe if it is attacked by an enemy
1138 // pawn, or if it is undefended and attacked by an enemy piece.
1140 Bitboard safeSquares = SpaceMask[Us]
1141 & ~pos.pieces(PAWN, Us)
1142 & ~ei.attacked_by(Them, PAWN)
1143 & ~(~ei.attacked_by(Us) & ei.attacked_by(Them));
1145 // Find all squares which are at most three squares behind some friendly
1147 Bitboard behindFriendlyPawns = pos.pieces(PAWN, Us);
1148 behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 8 : behindFriendlyPawns << 8);
1149 behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 16 : behindFriendlyPawns << 16);
1151 int space = count_1s_max_15<HasPopCnt>(safeSquares)
1152 + count_1s_max_15<HasPopCnt>(behindFriendlyPawns & safeSquares);
1154 ei.mgValue += Sign[Us] * apply_weight(Value(space * ei.mi->space_weight()), WeightSpace);
1158 // apply_weight() applies an evaluation weight to a value
1160 inline Value apply_weight(Value v, int w) {
1161 return (v*w) / 0x100;
1165 // scale_by_game_phase() interpolates between a middle game and an endgame
1166 // score, based on game phase. It also scales the return value by a
1167 // ScaleFactor array.
1169 Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]) {
1171 assert(mv > -VALUE_INFINITE && mv < VALUE_INFINITE);
1172 assert(ev > -VALUE_INFINITE && ev < VALUE_INFINITE);
1173 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1175 ev = apply_scale_factor(ev, sf[(ev > Value(0) ? WHITE : BLACK)]);
1177 Value result = Value(int((mv * ph + ev * (128 - ph)) / 128));
1178 return Value(int(result) & ~(GrainSize - 1));
1182 // weight_option() computes the value of an evaluation weight, by combining
1183 // an UCI-configurable weight with an internal weight.
1185 int weight_option(const std::string& opt, int internalWeight) {
1187 int uciWeight = get_option_value_int(opt);
1188 uciWeight = (uciWeight * 0x100) / 100;
1189 return (uciWeight * internalWeight) / 0x100;
1193 // init_safety() initizes the king safety evaluation, based on UCI
1194 // parameters. It is called from read_weights().
1196 void init_safety() {
1198 QueenContactCheckBonus = get_option_value_int("Queen Contact Check Bonus");
1199 QueenCheckBonus = get_option_value_int("Queen Check Bonus");
1200 RookCheckBonus = get_option_value_int("Rook Check Bonus");
1201 BishopCheckBonus = get_option_value_int("Bishop Check Bonus");
1202 KnightCheckBonus = get_option_value_int("Knight Check Bonus");
1203 DiscoveredCheckBonus = get_option_value_int("Discovered Check Bonus");
1204 MateThreatBonus = get_option_value_int("Mate Threat Bonus");
1206 int maxSlope = get_option_value_int("King Safety Max Slope");
1207 int peak = get_option_value_int("King Safety Max Value") * 256 / 100;
1208 double a = get_option_value_int("King Safety Coefficient") / 100.0;
1209 double b = get_option_value_int("King Safety X Intercept");
1210 bool quad = (get_option_value_string("King Safety Curve") == "Quadratic");
1211 bool linear = (get_option_value_string("King Safety Curve") == "Linear");
1213 for (int i = 0; i < 100; i++)
1216 SafetyTable[i] = Value(0);
1218 SafetyTable[i] = Value((int)(a * (i - b) * (i - b)));
1220 SafetyTable[i] = Value((int)(100 * a * (i - b)));
1223 for (int i = 0; i < 100; i++)
1225 if (SafetyTable[i+1] - SafetyTable[i] > maxSlope)
1226 for (int j = i + 1; j < 100; j++)
1227 SafetyTable[j] = SafetyTable[j-1] + Value(maxSlope);
1229 if (SafetyTable[i] > Value(peak))
1230 SafetyTable[i] = Value(peak);