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/>.
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 enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem };
53 #define S(mg, eg) make_score(mg, eg)
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 Score WeightsInternal[] = {
62 S(248, 271), S(233, 201), S(252, 259), S(46, 0), S(247, 0), S(259, 0)
65 // Knight mobility bonus in middle game and endgame, indexed by the number
66 // of attacked squares not occupied by friendly piecess.
67 const Score KnightMobilityBonus[16] = {
68 S(-38,-33), S(-25,-23), S(-12,-13), S( 0,-3),
69 S( 12, 7), S( 25, 17), S( 31, 22), S(38, 27), S(38, 27)
72 // Bishop mobility bonus in middle game and endgame, indexed by the number
73 // of attacked squares not occupied by friendly pieces. X-ray attacks through
74 // queens are also included.
75 const Score BishopMobilityBonus[16] = {
76 S(-25,-30), S(-11,-16), S( 3, -2), S(17, 12),
77 S( 31, 26), S( 45, 40), S(57, 52), S(65, 60),
78 S( 71, 65), S( 74, 69), S(76, 71), S(78, 73),
79 S( 79, 74), S( 80, 75), S(81, 76), S(81, 76)
82 // Rook mobility bonus in middle game and endgame, indexed by the number
83 // of attacked squares not occupied by friendly pieces. X-ray attacks through
84 // queens and rooks are also included.
85 const Score RookMobilityBonus[16] = {
86 S(-20,-36), S(-14,-19), S(-8, -3), S(-2, 13),
87 S( 4, 29), S( 10, 46), S(14, 62), S(19, 79),
88 S( 23, 95), S( 26,106), S(27,111), S(28,114),
89 S( 29,116), S( 30,117), S(31,118), S(32,118)
92 // Queen mobility bonus in middle game and endgame, indexed by the number
93 // of attacked squares not occupied by friendly pieces.
94 const Score QueenMobilityBonus[32] = {
95 S(-10,-18), S(-8,-13), S(-6, -7), S(-3, -2), S(-1, 3), S( 1, 8),
96 S( 3, 13), S( 5, 19), S( 8, 23), S(10, 27), S(12, 32), S(15, 34),
97 S( 16, 35), S(17, 35), S(18, 35), S(20, 35), S(20, 35), S(20, 35),
98 S( 20, 35), S(20, 35), S(20, 35), S(20, 35), S(20, 35), S(20, 35),
99 S( 20, 35), S(20, 35), S(20, 35), S(20, 35), S(20, 35), S(20, 35),
100 S( 20, 35), S(20, 35)
103 // Pointers table to access mobility tables through piece type
104 const Score* MobilityBonus[8] = { 0, 0, KnightMobilityBonus, BishopMobilityBonus,
105 RookMobilityBonus, QueenMobilityBonus, 0, 0 };
107 // Outpost bonuses for knights and bishops, indexed by square (from white's
109 const Value KnightOutpostBonus[64] = {
111 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 1
112 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 2
113 V(0), V(0), V(4), V(8), V(8), V(4), V(0), V(0), // 3
114 V(0), V(4),V(17),V(26),V(26),V(17), V(4), V(0), // 4
115 V(0), V(8),V(26),V(35),V(35),V(26), V(8), V(0), // 5
116 V(0), V(4),V(17),V(17),V(17),V(17), V(4), V(0), // 6
117 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 7
118 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8
121 const Value BishopOutpostBonus[64] = {
123 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 1
124 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 2
125 V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0), // 3
126 V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0), // 4
127 V(0),V(10),V(21),V(21),V(21),V(21),V(10), V(0), // 5
128 V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0), // 6
129 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 7
130 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8
133 // ThreatBonus[attacking][attacked] contains bonus according to which
134 // piece type attacks which one.
135 const Score ThreatBonus[8][8] = {
137 { S(0, 0), S(18,37), S( 0, 0), S(37,47), S(55,97), S(55,97) }, // KNIGHT
138 { S(0, 0), S(18,37), S(37,47), S( 0, 0), S(55,97), S(55,97) }, // BISHOP
139 { S(0, 0), S( 9,27), S(27,47), S(27,47), S( 0, 0), S(37,47) }, // ROOK
140 { S(0, 0), S(27,37), S(27,37), S(27,37), S(27,37), S( 0, 0) }, // QUEEN
144 // ThreatedByPawnPenalty[] contains a penalty according to which piece
145 // type is attacked by an enemy pawn.
146 const Score ThreatedByPawnPenalty[8] = {
147 S(0, 0), S(0, 0), S(56, 70), S(56, 70), S(76, 99), S(86, 118)
152 // Bonus for unstoppable passed pawns
153 const Value UnstoppablePawnValue = Value(0x500);
155 // Rooks and queens on the 7th rank (modified by Joona Kiiski)
156 const Score RookOn7thBonus = make_score(47, 98);
157 const Score QueenOn7thBonus = make_score(27, 54);
159 // Rooks on open files (modified by Joona Kiiski)
160 const Score RookOpenFileBonus = make_score(43, 43);
161 const Score RookHalfOpenFileBonus = make_score(19, 19);
163 // Penalty for rooks trapped inside a friendly king which has lost the
165 const Value TrappedRookPenalty = Value(180);
167 // Penalty for a bishop on a7/h7 (a2/h2 for black) which is trapped by
169 const Score TrappedBishopA7H7Penalty = make_score(300, 300);
171 // Bitboard masks for detecting trapped bishops on a7/h7 (a2/h2 for black)
172 const Bitboard MaskA7H7[2] = {
173 ((1ULL << SQ_A7) | (1ULL << SQ_H7)),
174 ((1ULL << SQ_A2) | (1ULL << SQ_H2))
177 // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
178 // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
179 // happen in Chess960 games.
180 const Score TrappedBishopA1H1Penalty = make_score(100, 100);
182 // Bitboard masks for detecting trapped bishops on a1/h1 (a8/h8 for black)
183 const Bitboard MaskA1H1[2] = {
184 ((1ULL << SQ_A1) | (1ULL << SQ_H1)),
185 ((1ULL << SQ_A8) | (1ULL << SQ_H8))
188 // The SpaceMask[color] contains the area of the board which is considered
189 // by the space evaluation. In the middle game, each side is given a bonus
190 // based on how many squares inside this area are safe and available for
191 // friendly minor pieces.
192 const Bitboard SpaceMask[2] = {
193 (1ULL<<SQ_C2) | (1ULL<<SQ_D2) | (1ULL<<SQ_E2) | (1ULL<<SQ_F2) |
194 (1ULL<<SQ_C3) | (1ULL<<SQ_D3) | (1ULL<<SQ_E3) | (1ULL<<SQ_F3) |
195 (1ULL<<SQ_C4) | (1ULL<<SQ_D4) | (1ULL<<SQ_E4) | (1ULL<<SQ_F4),
196 (1ULL<<SQ_C7) | (1ULL<<SQ_D7) | (1ULL<<SQ_E7) | (1ULL<<SQ_F7) |
197 (1ULL<<SQ_C6) | (1ULL<<SQ_D6) | (1ULL<<SQ_E6) | (1ULL<<SQ_F6) |
198 (1ULL<<SQ_C5) | (1ULL<<SQ_D5) | (1ULL<<SQ_E5) | (1ULL<<SQ_F5)
201 /// King danger constants and variables. The king danger scores are taken
202 /// from the KingDangerTable[]. Various little "meta-bonuses" measuring
203 /// the strength of the enemy attack are added up into an integer, which
204 /// is used as an index to KingDangerTable[].
206 // Attack weights for each piece type and table indexed on piece type
207 const int QueenAttackWeight = 5;
208 const int RookAttackWeight = 3;
209 const int BishopAttackWeight = 2;
210 const int KnightAttackWeight = 2;
212 const int AttackWeight[] = { 0, 0, KnightAttackWeight, BishopAttackWeight, RookAttackWeight, QueenAttackWeight };
214 // Bonuses for enemy's safe checks
215 const int QueenContactCheckBonus = 3;
216 const int DiscoveredCheckBonus = 3;
217 const int QueenCheckBonus = 2;
218 const int RookCheckBonus = 1;
219 const int BishopCheckBonus = 1;
220 const int KnightCheckBonus = 1;
222 // Scan for queen contact mates?
223 const bool QueenContactMates = true;
225 // Bonus for having a mate threat
226 const int MateThreatBonus = 3;
228 // InitKingDanger[] contains bonuses based on the position of the defending
230 const int InitKingDanger[64] = {
231 2, 0, 2, 5, 5, 2, 0, 2,
232 2, 2, 4, 8, 8, 4, 2, 2,
233 7, 10, 12, 12, 12, 12, 10, 7,
234 15, 15, 15, 15, 15, 15, 15, 15,
235 15, 15, 15, 15, 15, 15, 15, 15,
236 15, 15, 15, 15, 15, 15, 15, 15,
237 15, 15, 15, 15, 15, 15, 15, 15,
238 15, 15, 15, 15, 15, 15, 15, 15
241 // KingDangerTable[color][] contains the actual king danger weighted scores
242 Score KingDangerTable[2][128];
244 // Pawn and material hash tables, indexed by the current thread id.
245 // Note that they will be initialized at 0 being global variables.
246 MaterialInfoTable* MaterialTable[MAX_THREADS];
247 PawnInfoTable* PawnTable[MAX_THREADS];
249 // Sizes of pawn and material hash tables
250 const int PawnTableSize = 16384;
251 const int MaterialTableSize = 1024;
253 // Function prototypes
254 template<bool HasPopCnt>
255 Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID);
257 template<Color Us, bool HasPopCnt>
258 void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei);
260 template<Color Us, bool HasPopCnt>
261 void evaluate_king(const Position& pos, EvalInfo& ei);
264 void evaluate_threats(const Position& pos, EvalInfo& ei);
266 template<Color Us, bool HasPopCnt>
267 void evaluate_space(const Position& pos, EvalInfo& ei);
270 void evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
272 void evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
273 void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo& ei);
274 void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei);
275 inline Score apply_weight(Score v, Score weight);
276 Value scale_by_game_phase(const Score& v, Phase ph, const ScaleFactor sf[]);
277 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
286 /// evaluate() is the main evaluation function. It always computes two
287 /// values, an endgame score and a middle game score, and interpolates
288 /// between them based on the remaining material.
289 Value evaluate(const Position& pos, EvalInfo& ei, int threadID) {
291 return CpuHasPOPCNT ? do_evaluate<true>(pos, ei, threadID)
292 : do_evaluate<false>(pos, ei, threadID);
297 template<bool HasPopCnt>
298 Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID) {
301 ScaleFactor factor[2];
304 assert(threadID >= 0 && threadID < MAX_THREADS);
305 assert(!pos.is_check());
307 memset(&ei, 0, sizeof(EvalInfo));
309 // Initialize by reading the incrementally updated scores included in the
310 // position object (material + piece square tables)
311 ei.value = pos.value();
313 // Probe the material hash table
314 ei.mi = MaterialTable[threadID]->get_material_info(pos);
315 ei.value += ei.mi->material_value();
317 // If we have a specialized evaluation function for the current material
318 // configuration, call it and return
319 if (ei.mi->specialized_eval_exists())
320 return ei.mi->evaluate(pos);
322 // After get_material_info() call that modifies them
323 factor[WHITE] = ei.mi->scale_factor(pos, WHITE);
324 factor[BLACK] = ei.mi->scale_factor(pos, BLACK);
326 // Probe the pawn hash table
327 ei.pi = PawnTable[threadID]->get_pawn_info(pos);
328 ei.value += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
330 // Initialize king attack bitboards and king attack zones for both sides
331 ei.attackedBy[WHITE][KING] = pos.attacks_from<KING>(pos.king_square(WHITE));
332 ei.attackedBy[BLACK][KING] = pos.attacks_from<KING>(pos.king_square(BLACK));
333 ei.kingZone[WHITE] = ei.attackedBy[BLACK][KING] | (ei.attackedBy[BLACK][KING] >> 8);
334 ei.kingZone[BLACK] = ei.attackedBy[WHITE][KING] | (ei.attackedBy[WHITE][KING] << 8);
336 // Initialize pawn attack bitboards for both sides
337 ei.attackedBy[WHITE][PAWN] = ei.pi->pawn_attacks(WHITE);
338 b = ei.attackedBy[WHITE][PAWN] & ei.attackedBy[BLACK][KING];
340 ei.kingAttackersCount[WHITE] = count_1s_max_15<HasPopCnt>(b)/2;
342 ei.attackedBy[BLACK][PAWN] = ei.pi->pawn_attacks(BLACK);
343 b = ei.attackedBy[BLACK][PAWN] & ei.attackedBy[WHITE][KING];
345 ei.kingAttackersCount[BLACK] = count_1s_max_15<HasPopCnt>(b)/2;
348 evaluate_pieces_of_color<WHITE, HasPopCnt>(pos, ei);
349 evaluate_pieces_of_color<BLACK, HasPopCnt>(pos, ei);
351 // Kings. Kings are evaluated after all other pieces for both sides,
352 // because we need complete attack information for all pieces when computing
353 // the king safety evaluation.
354 evaluate_king<WHITE, HasPopCnt>(pos, ei);
355 evaluate_king<BLACK, HasPopCnt>(pos, ei);
357 // Evaluate tactical threats, we need full attack info including king
358 evaluate_threats<WHITE>(pos, ei);
359 evaluate_threats<BLACK>(pos, ei);
361 // Evaluate passed pawns, we need full attack info including king
362 evaluate_passed_pawns<WHITE>(pos, ei);
363 evaluate_passed_pawns<BLACK>(pos, ei);
365 // If one side has only a king, check whether exsists any unstoppable passed pawn
366 if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
367 evaluate_unstoppable_pawns(pos, ei);
369 Phase phase = ei.mi->game_phase();
371 // Middle-game specific evaluation terms
372 if (phase > PHASE_ENDGAME)
374 // Pawn storms in positions with opposite castling
375 if ( square_file(pos.king_square(WHITE)) >= FILE_E
376 && square_file(pos.king_square(BLACK)) <= FILE_D)
378 ei.value += make_score(ei.pi->queenside_storm_value(WHITE) - ei.pi->kingside_storm_value(BLACK), 0);
380 else if ( square_file(pos.king_square(WHITE)) <= FILE_D
381 && square_file(pos.king_square(BLACK)) >= FILE_E)
383 ei.value += make_score(ei.pi->kingside_storm_value(WHITE) - ei.pi->queenside_storm_value(BLACK), 0);
385 // Evaluate space for both sides
386 if (ei.mi->space_weight() > 0)
388 evaluate_space<WHITE, HasPopCnt>(pos, ei);
389 evaluate_space<BLACK, HasPopCnt>(pos, ei);
394 ei.value += apply_weight(ei.mobility, Weights[Mobility]);
396 // If we don't already have an unusual scale factor, check for opposite
397 // colored bishop endgames, and use a lower scale for those
398 if ( phase < PHASE_MIDGAME
399 && pos.opposite_colored_bishops()
400 && ( (factor[WHITE] == SCALE_FACTOR_NORMAL && eg_value(ei.value) > Value(0))
401 || (factor[BLACK] == SCALE_FACTOR_NORMAL && eg_value(ei.value) < Value(0))))
405 // Only the two bishops ?
406 if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
407 && pos.non_pawn_material(BLACK) == BishopValueMidgame)
409 // Check for KBP vs KB with only a single pawn that is almost
410 // certainly a draw or at least two pawns.
411 bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
412 sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
415 // Endgame with opposite-colored bishops, but also other pieces. Still
416 // a bit drawish, but not as drawish as with only the two bishops.
417 sf = ScaleFactor(50);
419 if (factor[WHITE] == SCALE_FACTOR_NORMAL)
421 if (factor[BLACK] == SCALE_FACTOR_NORMAL)
425 // Interpolate between the middle game and the endgame score
426 Color stm = pos.side_to_move();
428 Value v = Sign[stm] * scale_by_game_phase(ei.value, phase, factor);
430 return (ei.mateThreat[stm] == MOVE_NONE ? v : 8 * QueenValueMidgame - v);
435 /// init_eval() initializes various tables used by the evaluation function
437 void init_eval(int threads) {
439 assert(threads <= MAX_THREADS);
441 for (int i = 0; i < MAX_THREADS; i++)
446 delete MaterialTable[i];
448 MaterialTable[i] = NULL;
452 PawnTable[i] = new PawnInfoTable(PawnTableSize);
453 if (!MaterialTable[i])
454 MaterialTable[i] = new MaterialInfoTable(MaterialTableSize);
459 /// quit_eval() releases heap-allocated memory at program termination
463 for (int i = 0; i < MAX_THREADS; i++)
466 delete MaterialTable[i];
468 MaterialTable[i] = NULL;
473 /// read_weights() reads evaluation weights from the corresponding UCI parameters
475 void read_weights(Color us) {
477 // King safety is asymmetrical. Our king danger level is weighted by
478 // "Cowardice" UCI parameter, instead the opponent one by "Aggressiveness".
479 const int kingDangerUs = (us == WHITE ? KingDangerUs : KingDangerThem);
480 const int kingDangerThem = (us == WHITE ? KingDangerThem : KingDangerUs);
482 Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
483 Weights[PawnStructure] = weight_option("Pawn Structure (Middle Game)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
484 Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
485 Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
486 Weights[kingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
487 Weights[kingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
489 // If running in analysis mode, make sure we use symmetrical king safety. We do this
490 // by replacing both Weights[kingDangerUs] and Weights[kingDangerThem] by their average.
491 if (get_option_value_bool("UCI_AnalyseMode"))
492 Weights[kingDangerUs] = Weights[kingDangerThem] = (Weights[kingDangerUs] + Weights[kingDangerThem]) / 2;
500 // evaluate_outposts() evaluates bishop and knight outposts squares
502 template<PieceType Piece, Color Us>
503 void evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
505 const Color Them = (Us == WHITE ? BLACK : WHITE);
507 // Initial bonus based on square
508 Value bonus = (Piece == BISHOP ? BishopOutpostBonus[relative_square(Us, s)]
509 : KnightOutpostBonus[relative_square(Us, s)]);
511 // Increase bonus if supported by pawn, especially if the opponent has
512 // no minor piece which can exchange the outpost piece
513 if (bonus && bit_is_set(ei.attackedBy[Us][PAWN], s))
515 if ( pos.pieces(KNIGHT, Them) == EmptyBoardBB
516 && (SquaresByColorBB[square_color(s)] & pos.pieces(BISHOP, Them)) == EmptyBoardBB)
517 bonus += bonus + bonus / 2;
521 ei.value += Sign[Us] * make_score(bonus, bonus);
525 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
527 template<PieceType Piece, Color Us, bool HasPopCnt>
528 void evaluate_pieces(const Position& pos, EvalInfo& ei, Bitboard no_mob_area) {
535 const Color Them = (Us == WHITE ? BLACK : WHITE);
536 const Square* ptr = pos.piece_list_begin(Us, Piece);
538 while ((s = *ptr++) != SQ_NONE)
540 // Find attacked squares, including x-ray attacks for bishops and rooks
541 if (Piece == KNIGHT || Piece == QUEEN)
542 b = pos.attacks_from<Piece>(s);
543 else if (Piece == BISHOP)
544 b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
545 else if (Piece == ROOK)
546 b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
550 // Update attack info
551 ei.attackedBy[Us][Piece] |= b;
554 if (b & ei.kingZone[Us])
556 ei.kingAttackersCount[Us]++;
557 ei.kingAttackersWeight[Us] += AttackWeight[Piece];
558 Bitboard bb = (b & ei.attackedBy[Them][KING]);
560 ei.kingAdjacentZoneAttacksCount[Us] += count_1s_max_15<HasPopCnt>(bb);
564 mob = (Piece != QUEEN ? count_1s_max_15<HasPopCnt>(b & no_mob_area)
565 : count_1s<HasPopCnt>(b & no_mob_area));
567 ei.mobility += Sign[Us] * MobilityBonus[Piece][mob];
569 // Decrease score if we are attacked by an enemy pawn. Remaining part
570 // of threat evaluation must be done later when we have full attack info.
571 if (bit_is_set(ei.attackedBy[Them][PAWN], s))
572 ei.value -= Sign[Us] * ThreatedByPawnPenalty[Piece];
574 // Bishop and knight outposts squares
575 if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Them))
576 evaluate_outposts<Piece, Us>(pos, ei, s);
578 // Special patterns: trapped bishops on a7/h7/a2/h2
579 // and trapped bishops on a1/h1/a8/h8 in Chess960.
582 if (bit_is_set(MaskA7H7[Us], s))
583 evaluate_trapped_bishop_a7h7(pos, s, Us, ei);
585 if (Chess960 && bit_is_set(MaskA1H1[Us], s))
586 evaluate_trapped_bishop_a1h1(pos, s, Us, ei);
589 // Queen or rook on 7th rank
590 if ( (Piece == ROOK || Piece == QUEEN)
591 && relative_rank(Us, s) == RANK_7
592 && relative_rank(Us, pos.king_square(Them)) == RANK_8)
594 ei.value += Sign[Us] * (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus);
597 // Special extra evaluation for rooks
600 // Open and half-open files
602 if (ei.pi->file_is_half_open(Us, f))
604 if (ei.pi->file_is_half_open(Them, f))
605 ei.value += Sign[Us] * RookOpenFileBonus;
607 ei.value += Sign[Us] * RookHalfOpenFileBonus;
610 // Penalize rooks which are trapped inside a king. Penalize more if
611 // king has lost right to castle.
612 if (mob > 6 || ei.pi->file_is_half_open(Us, f))
615 ksq = pos.king_square(Us);
617 if ( square_file(ksq) >= FILE_E
618 && square_file(s) > square_file(ksq)
619 && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
621 // Is there a half-open file between the king and the edge of the board?
622 if (!ei.pi->has_open_file_to_right(Us, square_file(ksq)))
623 ei.value -= Sign[Us] * make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
624 : (TrappedRookPenalty - mob * 16), 0);
626 else if ( square_file(ksq) <= FILE_D
627 && square_file(s) < square_file(ksq)
628 && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
630 // Is there a half-open file between the king and the edge of the board?
631 if (!ei.pi->has_open_file_to_left(Us, square_file(ksq)))
632 ei.value -= Sign[Us] * make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2
633 : (TrappedRookPenalty - mob * 16), 0);
640 // evaluate_threats<>() assigns bonuses according to the type of attacking piece
641 // and the type of attacked one.
644 void evaluate_threats(const Position& pos, EvalInfo& ei) {
646 const Color Them = (Us == WHITE ? BLACK : WHITE);
649 Score bonus = make_score(0, 0);
651 // Enemy pieces not defended by a pawn and under our attack
652 Bitboard weakEnemies = pos.pieces_of_color(Them)
653 & ~ei.attackedBy[Them][PAWN]
654 & ei.attackedBy[Us][0];
658 // Add bonus according to type of attacked enemy pieces and to the
659 // type of attacking piece, from knights to queens. Kings are not
660 // considered because are already special handled in king evaluation.
661 for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++)
663 b = ei.attackedBy[Us][pt1] & weakEnemies;
665 for (PieceType pt2 = PAWN; pt2 < KING; pt2++)
666 if (b & pos.pieces(pt2))
667 bonus += ThreatBonus[pt1][pt2];
669 ei.value += Sign[Us] * bonus;
673 // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
674 // pieces of a given color.
676 template<Color Us, bool HasPopCnt>
677 void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei) {
679 const Color Them = (Us == WHITE ? BLACK : WHITE);
681 // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
682 const Bitboard no_mob_area = ~(ei.attackedBy[Them][PAWN] | pos.pieces_of_color(Us));
684 evaluate_pieces<KNIGHT, Us, HasPopCnt>(pos, ei, no_mob_area);
685 evaluate_pieces<BISHOP, Us, HasPopCnt>(pos, ei, no_mob_area);
686 evaluate_pieces<ROOK, Us, HasPopCnt>(pos, ei, no_mob_area);
687 evaluate_pieces<QUEEN, Us, HasPopCnt>(pos, ei, no_mob_area);
689 // Sum up all attacked squares
690 ei.attackedBy[Us][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
691 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
692 | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
696 // evaluate_king<>() assigns bonuses and penalties to a king of a given color
698 template<Color Us, bool HasPopCnt>
699 void evaluate_king(const Position& pos, EvalInfo& ei) {
701 const Color Them = (Us == WHITE ? BLACK : WHITE);
703 Bitboard undefended, attackedByOthers, escapeSquares, occ, b, b1, b2, safe;
706 int attackUnits, shelter = 0;
707 const Square ksq = pos.king_square(Us);
710 if (relative_rank(Us, ksq) <= RANK_4)
712 shelter = ei.pi->get_king_shelter(pos, Us, ksq);
713 ei.value += Sign[Us] * make_score(shelter, 0);
716 // King safety. This is quite complicated, and is almost certainly far
717 // from optimally tuned.
718 if ( pos.piece_count(Them, QUEEN) >= 1
719 && ei.kingAttackersCount[Them] >= 2
720 && pos.non_pawn_material(Them) >= QueenValueMidgame + RookValueMidgame
721 && ei.kingAdjacentZoneAttacksCount[Them])
723 // Is it the attackers turn to move?
724 sente = (Them == pos.side_to_move());
726 // Find the attacked squares around the king which has no defenders
727 // apart from the king itself
728 undefended = ei.attacked_by(Them) & ei.attacked_by(Us, KING);
729 undefended &= ~( ei.attacked_by(Us, PAWN) | ei.attacked_by(Us, KNIGHT)
730 | ei.attacked_by(Us, BISHOP) | ei.attacked_by(Us, ROOK)
731 | ei.attacked_by(Us, QUEEN));
733 // Initialize the 'attackUnits' variable, which is used later on as an
734 // index to the KingDangerTable[] array. The initial value is based on
735 // the number and types of the enemy's attacking pieces, the number of
736 // attacked and undefended squares around our king, the square of the
737 // king, and the quality of the pawn shelter.
738 attackUnits = Min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
739 + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + count_1s_max_15<HasPopCnt>(undefended))
740 + InitKingDanger[relative_square(Us, ksq)]
743 // Analyse safe queen contact checks
744 b = undefended & ei.attacked_by(Them, QUEEN) & ~pos.pieces_of_color(Them);
747 attackedByOthers = ei.attacked_by(Them, PAWN) | ei.attacked_by(Them, KNIGHT)
748 | ei.attacked_by(Them, BISHOP) | ei.attacked_by(Them, ROOK);
750 b &= attackedByOthers;
752 // Squares attacked by the queen and supported by another enemy piece and
753 // not defended by other pieces but our king.
756 // The bitboard b now contains the squares available for safe queen
758 attackUnits += QueenContactCheckBonus * count_1s_max_15<HasPopCnt>(b) * (sente ? 2 : 1);
760 // Is there a mate threat?
761 if (QueenContactMates && !pos.is_check())
763 escapeSquares = pos.attacks_from<KING>(ksq) & ~pos.pieces_of_color(Us) & ~attackedByOthers;
764 occ = pos.occupied_squares();
767 to = pop_1st_bit(&b);
769 // Do we have escape squares from queen contact check attack ?
770 if (!(escapeSquares & ~queen_attacks_bb(to, occ & ClearMaskBB[ksq])))
772 // We have a mate, unless the queen is pinned or there
773 // is an X-ray attack through the queen.
774 for (int i = 0; i < pos.piece_count(Them, QUEEN); i++)
776 from = pos.piece_list(Them, QUEEN, i);
777 if ( bit_is_set(pos.attacks_from<QUEEN>(from), to)
778 && !bit_is_set(pos.pinned_pieces(Them), from)
779 && !(rook_attacks_bb(to, occ & ClearMaskBB[from]) & pos.pieces(ROOK, QUEEN, Us))
780 && !(bishop_attacks_bb(to, occ & ClearMaskBB[from]) & pos.pieces(BISHOP, QUEEN, Us)))
782 // Set the mate threat move
783 ei.mateThreat[Them] = make_move(from, to);
791 // Analyse enemy's safe distance checks
792 safe = ~(pos.pieces_of_color(Them) | ei.attacked_by(Us));
794 b1 = pos.attacks_from<ROOK>(ksq) & safe;
795 b2 = pos.attacks_from<BISHOP>(ksq) & safe;
797 // Enemy rooks safe checks
798 b = b1 & ei.attacked_by(Them, ROOK);
800 attackUnits += RookCheckBonus * count_1s_max_15<HasPopCnt>(b);
802 // Enemy bishops safe checks
803 b = b2 & ei.attacked_by(Them, BISHOP);
805 attackUnits += BishopCheckBonus * count_1s_max_15<HasPopCnt>(b);
807 // Enemy queens safe checks
808 b = (b1 | b2) & ei.attacked_by(Them, QUEEN);
810 attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b);
812 // Enemy knights safe checks
813 b = pos.attacks_from<KNIGHT>(ksq) & ei.attacked_by(Them, KNIGHT) & safe;
815 attackUnits += KnightCheckBonus * count_1s_max_15<HasPopCnt>(b);
817 // Analyse discovered checks (only for non-pawns right now, consider
818 // adding pawns later).
819 b = pos.discovered_check_candidates(Them) & ~pos.pieces(PAWN);
821 attackUnits += DiscoveredCheckBonus * count_1s_max_15<HasPopCnt>(b) * (sente ? 2 : 1);
823 // Has a mate threat been found? We don't do anything here if the
824 // side with the mating move is the side to move, because in that
825 // case the mating side will get a huge bonus at the end of the main
826 // evaluation function instead.
827 if (ei.mateThreat[Them] != MOVE_NONE)
828 attackUnits += MateThreatBonus;
830 // Ensure that attackUnits is between 0 and 99, in order to avoid array
831 // out of bounds errors.
832 attackUnits = Min(99, Max(0, attackUnits));
834 // Finally, extract the king danger score from the KingDangerTable[]
835 // array and subtract the score from evaluation. Set also ei.kingDanger[]
836 // value that will be used for pruning because this value can sometimes
837 // be very big, and so capturing a single attacking piece can therefore
838 // result in a score change far bigger than the value of the captured piece.
839 ei.value -= Sign[Us] * KingDangerTable[Us][attackUnits];
840 ei.kingDanger[Us] = mg_value(KingDangerTable[Us][attackUnits]);
845 // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
848 void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
850 const Color Them = (Us == WHITE ? BLACK : WHITE);
852 Bitboard b = ei.pi->passed_pawns() & pos.pieces_of_color(Us);
856 Square s = pop_1st_bit(&b);
858 assert(pos.piece_on(s) == piece_of_color_and_type(Us, PAWN));
859 assert(pos.pawn_is_passed(Us, s));
861 int r = int(relative_rank(Us, s) - RANK_2);
862 int tr = Max(0, r * (r - 1));
864 // Base bonus based on rank
865 Value mbonus = Value(20 * tr);
866 Value ebonus = Value(10 + r * r * 10);
868 // Adjust bonus based on king proximity
871 Square blockSq = s + pawn_push(Us);
873 ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 3 * tr);
874 ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * 1 * tr);
875 ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 6 * tr);
877 // If the pawn is free to advance, increase bonus
878 if (pos.square_is_empty(blockSq))
880 // There are no enemy pawns in the pawn's path
881 Bitboard b2 = squares_in_front_of(Us, s);
883 assert((b2 & pos.pieces(PAWN, Them)) == EmptyBoardBB);
885 // Squares attacked by us
886 Bitboard b4 = b2 & ei.attacked_by(Us);
888 // Squares attacked or occupied by enemy pieces
889 Bitboard b3 = b2 & (ei.attacked_by(Them) | pos.pieces_of_color(Them));
891 // If there is an enemy rook or queen attacking the pawn from behind,
892 // add all X-ray attacks by the rook or queen.
893 if ( (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them))
894 && (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from<QUEEN>(s)))
897 // Are any of the squares in the pawn's path attacked or occupied by the enemy?
898 if (b3 == EmptyBoardBB)
899 // No enemy attacks or pieces, huge bonus!
900 // Even bigger if we protect the pawn's path
901 ebonus += Value(tr * (b2 == b4 ? 17 : 15));
903 // OK, there are enemy attacks or pieces (but not pawns). Are those
904 // squares which are attacked by the enemy also attacked by us ?
905 // If yes, big bonus (but smaller than when there are no enemy attacks),
906 // if no, somewhat smaller bonus.
907 ebonus += Value(tr * ((b3 & b4) == b3 ? 13 : 8));
909 // At last, add a small bonus when there are no *friendly* pieces
910 // in the pawn's path.
911 if ((b2 & pos.pieces_of_color(Us)) == EmptyBoardBB)
916 // If the pawn is supported by a friendly pawn, increase bonus
917 Bitboard b1 = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
919 ebonus += Value(r * 20);
920 else if (pos.attacks_from<PAWN>(s, Them) & b1)
921 ebonus += Value(r * 12);
923 // Rook pawns are a special case: They are sometimes worse, and
924 // sometimes better than other passed pawns. It is difficult to find
925 // good rules for determining whether they are good or bad. For now,
926 // we try the following: Increase the value for rook pawns if the
927 // other side has no pieces apart from a knight, and decrease the
928 // value if the other side has a rook or queen.
929 if (square_file(s) == FILE_A || square_file(s) == FILE_H)
931 if ( pos.non_pawn_material(Them) <= KnightValueMidgame
932 && pos.piece_count(Them, KNIGHT) <= 1)
933 ebonus += ebonus / 4;
934 else if (pos.pieces(ROOK, QUEEN, Them))
935 ebonus -= ebonus / 4;
938 // Add the scores for this pawn to the middle game and endgame eval
939 ei.value += Sign[Us] * apply_weight(make_score(mbonus, ebonus), Weights[PassedPawns]);
945 // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides
947 void evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
949 int movesToGo[2] = {0, 0};
950 Square pawnToGo[2] = {SQ_NONE, SQ_NONE};
952 for (Color c = WHITE; c <= BLACK; c++)
954 // Skip evaluation if other side has non-pawn pieces
955 if (pos.non_pawn_material(opposite_color(c)))
958 Bitboard b = ei.pi->passed_pawns() & pos.pieces_of_color(c);
962 Square s = pop_1st_bit(&b);
963 Square queeningSquare = relative_square(c, make_square(square_file(s), RANK_8));
964 int d = square_distance(s, queeningSquare)
965 - square_distance(pos.king_square(opposite_color(c)), queeningSquare)
966 + int(c != pos.side_to_move());
970 int mtg = RANK_8 - relative_rank(c, s);
971 int blockerCount = count_1s_max_15(squares_in_front_of(c, s) & pos.occupied_squares());
974 if (d < 0 && (!movesToGo[c] || movesToGo[c] > mtg))
983 // Neither side has an unstoppable passed pawn?
984 if (!(movesToGo[WHITE] | movesToGo[BLACK]))
987 // Does only one side have an unstoppable passed pawn?
988 if (!movesToGo[WHITE] || !movesToGo[BLACK])
990 Color winnerSide = movesToGo[WHITE] ? WHITE : BLACK;
991 ei.value += make_score(0, Sign[winnerSide] * (UnstoppablePawnValue - Value(0x40 * movesToGo[winnerSide])));
994 { // Both sides have unstoppable pawns! Try to find out who queens
995 // first. We begin by transforming 'movesToGo' to the number of
996 // plies until the pawn queens for both sides.
997 movesToGo[WHITE] *= 2;
998 movesToGo[BLACK] *= 2;
999 movesToGo[pos.side_to_move()]--;
1001 Color winnerSide = movesToGo[WHITE] < movesToGo[BLACK] ? WHITE : BLACK;
1002 Color loserSide = opposite_color(winnerSide);
1004 // If one side queens at least three plies before the other, that side wins
1005 if (movesToGo[winnerSide] <= movesToGo[loserSide] - 3)
1006 ei.value += Sign[winnerSide] * make_score(0, UnstoppablePawnValue - Value(0x40 * (movesToGo[winnerSide]/2)));
1008 // If one side queens one ply before the other and checks the king or attacks
1009 // the undefended opponent's queening square, that side wins. To avoid cases
1010 // where the opponent's king could move somewhere before first pawn queens we
1011 // consider only free paths to queen for both pawns.
1012 else if ( !(squares_in_front_of(WHITE, pawnToGo[WHITE]) & pos.occupied_squares())
1013 && !(squares_in_front_of(BLACK, pawnToGo[BLACK]) & pos.occupied_squares()))
1015 assert(movesToGo[loserSide] - movesToGo[winnerSide] == 1);
1017 Square winnerQSq = relative_square(winnerSide, make_square(square_file(pawnToGo[winnerSide]), RANK_8));
1018 Square loserQSq = relative_square(loserSide, make_square(square_file(pawnToGo[loserSide]), RANK_8));
1020 Bitboard b = pos.occupied_squares();
1021 clear_bit(&b, pawnToGo[winnerSide]);
1022 clear_bit(&b, pawnToGo[loserSide]);
1023 b = queen_attacks_bb(winnerQSq, b);
1025 if ( (b & pos.pieces(KING, loserSide))
1026 ||(bit_is_set(b, loserQSq) && !bit_is_set(ei.attacked_by(loserSide), loserQSq)))
1027 ei.value += Sign[winnerSide] * make_score(0, UnstoppablePawnValue - Value(0x40 * (movesToGo[winnerSide]/2)));
1033 // evaluate_trapped_bishop_a7h7() determines whether a bishop on a7/h7
1034 // (a2/h2 for black) is trapped by enemy pawns, and assigns a penalty
1037 void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo &ei) {
1039 assert(square_is_ok(s));
1040 assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
1042 Square b6 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B6 : SQ_G6);
1043 Square b8 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B8 : SQ_G8);
1045 if ( pos.piece_on(b6) == piece_of_color_and_type(opposite_color(us), PAWN)
1046 && pos.see(s, b6) < 0
1047 && pos.see(s, b8) < 0)
1049 ei.value -= Sign[us] * TrappedBishopA7H7Penalty;
1054 // evaluate_trapped_bishop_a1h1() determines whether a bishop on a1/h1
1055 // (a8/h8 for black) is trapped by a friendly pawn on b2/g2 (b7/g7 for
1056 // black), and assigns a penalty if it is. This pattern can obviously
1057 // only occur in Chess960 games.
1059 void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei) {
1061 Piece pawn = piece_of_color_and_type(us, PAWN);
1065 assert(square_is_ok(s));
1066 assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
1068 if (square_file(s) == FILE_A)
1070 b2 = relative_square(us, SQ_B2);
1071 b3 = relative_square(us, SQ_B3);
1072 c3 = relative_square(us, SQ_C3);
1076 b2 = relative_square(us, SQ_G2);
1077 b3 = relative_square(us, SQ_G3);
1078 c3 = relative_square(us, SQ_F3);
1081 if (pos.piece_on(b2) == pawn)
1085 if (!pos.square_is_empty(b3))
1086 penalty = 2 * TrappedBishopA1H1Penalty;
1087 else if (pos.piece_on(c3) == pawn)
1088 penalty = TrappedBishopA1H1Penalty;
1090 penalty = TrappedBishopA1H1Penalty / 2;
1092 ei.value -= Sign[us] * penalty;
1097 // evaluate_space() computes the space evaluation for a given side. The
1098 // space evaluation is a simple bonus based on the number of safe squares
1099 // available for minor pieces on the central four files on ranks 2--4. Safe
1100 // squares one, two or three squares behind a friendly pawn are counted
1101 // twice. Finally, the space bonus is scaled by a weight taken from the
1102 // material hash table.
1103 template<Color Us, bool HasPopCnt>
1104 void evaluate_space(const Position& pos, EvalInfo& ei) {
1106 const Color Them = (Us == WHITE ? BLACK : WHITE);
1108 // Find the safe squares for our pieces inside the area defined by
1109 // SpaceMask[us]. A square is unsafe if it is attacked by an enemy
1110 // pawn, or if it is undefended and attacked by an enemy piece.
1112 Bitboard safeSquares = SpaceMask[Us]
1113 & ~pos.pieces(PAWN, Us)
1114 & ~ei.attacked_by(Them, PAWN)
1115 & ~(~ei.attacked_by(Us) & ei.attacked_by(Them));
1117 // Find all squares which are at most three squares behind some friendly
1119 Bitboard behindFriendlyPawns = pos.pieces(PAWN, Us);
1120 behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 8 : behindFriendlyPawns << 8);
1121 behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 16 : behindFriendlyPawns << 16);
1123 int space = count_1s_max_15<HasPopCnt>(safeSquares)
1124 + count_1s_max_15<HasPopCnt>(behindFriendlyPawns & safeSquares);
1126 ei.value += Sign[Us] * apply_weight(make_score(space * ei.mi->space_weight(), 0), Weights[Space]);
1130 // apply_weight() applies an evaluation weight to a value trying to prevent overflow
1132 inline Score apply_weight(Score v, Score w) {
1133 return make_score((int(mg_value(v)) * mg_value(w)) / 0x100, (int(eg_value(v)) * eg_value(w)) / 0x100);
1137 // scale_by_game_phase() interpolates between a middle game and an endgame
1138 // score, based on game phase. It also scales the return value by a
1139 // ScaleFactor array.
1141 Value scale_by_game_phase(const Score& v, Phase ph, const ScaleFactor sf[]) {
1143 assert(mg_value(v) > -VALUE_INFINITE && mg_value(v) < VALUE_INFINITE);
1144 assert(eg_value(v) > -VALUE_INFINITE && eg_value(v) < VALUE_INFINITE);
1145 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1147 Value ev = apply_scale_factor(eg_value(v), sf[(eg_value(v) > Value(0) ? WHITE : BLACK)]);
1149 int result = (mg_value(v) * ph + ev * (128 - ph)) / 128;
1150 return Value(result & ~(GrainSize - 1));
1154 // weight_option() computes the value of an evaluation weight, by combining
1155 // two UCI-configurable weights (midgame and endgame) with an internal weight.
1157 Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
1159 Score uciWeight = make_score(get_option_value_int(mgOpt), get_option_value_int(egOpt));
1161 // Convert to integer to prevent overflow
1162 int mg = mg_value(uciWeight);
1163 int eg = eg_value(uciWeight);
1165 mg = (mg * 0x100) / 100;
1166 eg = (eg * 0x100) / 100;
1167 mg = (mg * mg_value(internalWeight)) / 0x100;
1168 eg = (eg * eg_value(internalWeight)) / 0x100;
1169 return make_score(mg, eg);
1172 // init_safety() initizes the king safety evaluation, based on UCI
1173 // parameters. It is called from read_weights().
1175 void init_safety() {
1183 // First setup the base table
1184 for (int i = 0; i < 100; i++)
1189 t[i] = Value((int)(a * (i - b) * (i - b)));
1192 for (int i = 1; i < 100; i++)
1194 if (t[i] - t[i - 1] > maxSlope)
1195 t[i] = t[i - 1] + Value(maxSlope);
1197 if (t[i] > Value(peak))
1201 // Then apply the weights and get the final KingDangerTable[] array
1202 for (Color c = WHITE; c <= BLACK; c++)
1203 for (int i = 0; i < 100; i++)
1204 KingDangerTable[c][i] = apply_weight(make_score(t[i], 0), Weights[KingDangerUs + c]);