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 consdered
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, const Bitboard& mob_bb, 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 };
539 // Update attack info
540 ei.attackedBy[Us][Piece] |= mob_bb;
543 if (mob_bb & ei.kingZone[Us])
545 ei.kingAttackersCount[Us]++;
546 ei.kingAttackersWeight[Us] += AttackWeight[Piece];
547 Bitboard b = (mob_bb & ei.attackedBy[Them][KING]);
549 ei.kingAdjacentZoneAttacksCount[Us] += count_1s_max_15<HasPopCnt>(b);
552 // Remove squares protected by enemy pawns or occupied by our pieces
553 Bitboard b = mob_bb & ~ei.attackedBy[Them][PAWN] & ~pos.pieces_of_color(Us);
556 int mob = (Piece != QUEEN ? count_1s_max_15<HasPopCnt>(b) : count_1s<HasPopCnt>(b));
558 ei.mgMobility += Sign[Us] * MgBonus[Piece][mob];
559 ei.egMobility += Sign[Us] * EgBonus[Piece][mob];
564 // evaluate_outposts() evaluates bishop and knight outposts squares
566 template<PieceType Piece, Color Us>
567 void evaluate_outposts(const Position& pos, EvalInfo& ei, Square s) {
569 const Color Them = (Us == WHITE ? BLACK : WHITE);
571 // Initial bonus based on square
572 Value bonus = (Piece == BISHOP ? BishopOutpostBonus[relative_square(Us, s)]
573 : KnightOutpostBonus[relative_square(Us, s)]);
575 // Increase bonus if supported by pawn, especially if the opponent has
576 // no minor piece which can exchange the outpost piece
577 if (bonus && (pos.attacks_from<PAWN>(s, Them) & pos.pieces(PAWN, Us)))
579 if ( pos.pieces(KNIGHT, Them) == EmptyBoardBB
580 && (SquaresByColorBB[square_color(s)] & pos.pieces(BISHOP, Them)) == EmptyBoardBB)
581 bonus += bonus + bonus / 2;
585 ei.mgValue += Sign[Us] * bonus;
586 ei.egValue += Sign[Us] * bonus;
590 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color
592 template<PieceType Piece, Color Us, bool HasPopCnt>
593 void evaluate_pieces(const Position& pos, EvalInfo& ei) {
600 const Color Them = (Us == WHITE ? BLACK : WHITE);
601 const Square* ptr = pos.piece_list_begin(Us, Piece);
603 while ((s = *ptr++) != SQ_NONE)
605 if (Piece == KNIGHT || Piece == QUEEN)
606 mob_bb = pos.attacks_from<Piece>(s);
607 else if (Piece == BISHOP)
608 mob_bb = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
609 else if (Piece == ROOK)
610 mob_bb = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
614 // Attacks and mobility
615 mob = evaluate_mobility<Piece, Us, HasPopCnt>(pos, mob_bb, ei);
617 // Bishop and knight outposts squares
618 if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Them))
619 evaluate_outposts<Piece, Us>(pos, ei, s);
621 // Special patterns: trapped bishops on a7/h7/a2/h2
622 // and trapped bishops on a1/h1/a8/h8 in Chess960.
625 if (bit_is_set(MaskA7H7[Us], s))
626 evaluate_trapped_bishop_a7h7(pos, s, Us, ei);
628 if (Chess960 && bit_is_set(MaskA1H1[Us], s))
629 evaluate_trapped_bishop_a1h1(pos, s, Us, ei);
632 if (Piece == ROOK || Piece == QUEEN)
634 // Queen or rook on 7th rank
635 if ( relative_rank(Us, s) == RANK_7
636 && relative_rank(Us, pos.king_square(Them)) == RANK_8)
638 ei.mgValue += Sign[Us] * (Piece == ROOK ? MidgameRookOn7thBonus : MidgameQueenOn7thBonus);
639 ei.egValue += Sign[Us] * (Piece == ROOK ? EndgameRookOn7thBonus : EndgameQueenOn7thBonus);
643 // Special extra evaluation for rooks
646 // Open and half-open files
648 if (ei.pi->file_is_half_open(Us, f))
650 if (ei.pi->file_is_half_open(Them, f))
652 ei.mgValue += Sign[Us] * RookOpenFileBonus;
653 ei.egValue += Sign[Us] * RookOpenFileBonus;
657 ei.mgValue += Sign[Us] * RookHalfOpenFileBonus;
658 ei.egValue += Sign[Us] * RookHalfOpenFileBonus;
662 // Penalize rooks which are trapped inside a king. Penalize more if
663 // king has lost right to castle.
664 if (mob > 6 || ei.pi->file_is_half_open(Us, f))
667 ksq = pos.king_square(Us);
669 if ( square_file(ksq) >= FILE_E
670 && square_file(s) > square_file(ksq)
671 && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
673 // Is there a half-open file between the king and the edge of the board?
674 if (!ei.pi->has_open_file_to_right(Us, square_file(ksq)))
675 ei.mgValue -= pos.can_castle(Us)? Sign[Us] * ((TrappedRookPenalty - mob * 16) / 2)
676 : Sign[Us] * (TrappedRookPenalty - mob * 16);
678 else if ( square_file(ksq) <= FILE_D
679 && square_file(s) < square_file(ksq)
680 && (relative_rank(Us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
682 // Is there a half-open file between the king and the edge of the board?
683 if (!ei.pi->has_open_file_to_left(Us, square_file(ksq)))
684 ei.mgValue -= pos.can_castle(Us)? Sign[Us] * ((TrappedRookPenalty - mob * 16) / 2)
685 : Sign[Us] * (TrappedRookPenalty - mob * 16);
692 // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the
693 // pieces of a given color.
695 template<Color Us, bool HasPopCnt>
696 void evaluate_pieces_of_color(const Position& pos, EvalInfo& ei) {
698 evaluate_pieces<KNIGHT, Us, HasPopCnt>(pos, ei);
699 evaluate_pieces<BISHOP, Us, HasPopCnt>(pos, ei);
700 evaluate_pieces<ROOK, Us, HasPopCnt>(pos, ei);
701 evaluate_pieces<QUEEN, Us, HasPopCnt>(pos, ei);
703 // Sum up all attacked squares
704 ei.attackedBy[Us][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
705 | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
706 | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
710 // evaluate_king<>() assigns bonuses and penalties to a king of a given color
712 template<Color Us, bool HasPopCnt>
713 void evaluate_king(const Position& pos, EvalInfo& ei) {
715 const Color Them = (Us == WHITE ? BLACK : WHITE);
716 const Square s = pos.king_square(Us);
720 if (relative_rank(Us, s) <= RANK_4)
722 shelter = ei.pi->get_king_shelter(pos, Us, s);
723 ei.mgValue += Sign[Us] * Value(shelter);
726 // King safety. This is quite complicated, and is almost certainly far
727 // from optimally tuned.
728 if ( pos.piece_count(Them, QUEEN) >= 1
729 && ei.kingAttackersCount[Them] >= 2
730 && pos.non_pawn_material(Them) >= QueenValueMidgame + RookValueMidgame
731 && ei.kingAdjacentZoneAttacksCount[Them])
733 // Is it the attackers turn to move?
734 bool sente = (Them == pos.side_to_move());
736 // Find the attacked squares around the king which has no defenders
737 // apart from the king itself
738 Bitboard undefended =
739 ei.attacked_by(Them) & ~ei.attacked_by(Us, PAWN)
740 & ~ei.attacked_by(Us, KNIGHT) & ~ei.attacked_by(Us, BISHOP)
741 & ~ei.attacked_by(Us, ROOK) & ~ei.attacked_by(Us, QUEEN)
742 & ei.attacked_by(Us, KING);
744 Bitboard occ = pos.occupied_squares(), b, b2;
746 // Initialize the 'attackUnits' variable, which is used later on as an
747 // index to the SafetyTable[] array. The initial value is based on the
748 // number and types of the attacking pieces, the number of attacked and
749 // undefended squares around the king, the square of the king, and the
750 // quality of the pawn shelter.
752 Min((ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2, 25)
753 + (ei.kingAdjacentZoneAttacksCount[Them] + count_1s_max_15<HasPopCnt>(undefended)) * 3
754 + InitKingDanger[relative_square(Us, s)] - (shelter >> 5);
756 // Analyse safe queen contact checks
757 b = undefended & ei.attacked_by(Them, QUEEN) & ~pos.pieces_of_color(Them);
760 Bitboard attackedByOthers =
761 ei.attacked_by(Them, PAWN) | ei.attacked_by(Them, KNIGHT)
762 | ei.attacked_by(Them, BISHOP) | ei.attacked_by(Them, ROOK);
764 b &= attackedByOthers;
767 // The bitboard b now contains the squares available for safe queen
769 int count = count_1s_max_15<HasPopCnt>(b);
770 attackUnits += QueenContactCheckBonus * count * (sente ? 2 : 1);
772 // Is there a mate threat?
773 if (QueenContactMates && !pos.is_check())
775 Bitboard escapeSquares =
776 pos.attacks_from<KING>(s) & ~pos.pieces_of_color(Us) & ~attackedByOthers;
780 Square from, to = pop_1st_bit(&b);
781 if (!(escapeSquares & ~queen_attacks_bb(to, occ & ClearMaskBB[s])))
783 // We have a mate, unless the queen is pinned or there
784 // is an X-ray attack through the queen.
785 for (int i = 0; i < pos.piece_count(Them, QUEEN); i++)
787 from = pos.piece_list(Them, QUEEN, i);
788 if ( bit_is_set(pos.attacks_from<QUEEN>(from), to)
789 && !bit_is_set(pos.pinned_pieces(Them), from)
790 && !(rook_attacks_bb(to, occ & ClearMaskBB[from]) & pos.pieces(ROOK, QUEEN, Us))
791 && !(bishop_attacks_bb(to, occ & ClearMaskBB[from]) & pos.pieces(BISHOP, QUEEN, Us)))
793 ei.mateThreat[Them] = make_move(from, to);
801 // Analyse safe distance checks
802 if (QueenCheckBonus > 0 || RookCheckBonus > 0)
804 b = pos.attacks_from<ROOK>(s) & ~pos.pieces_of_color(Them) & ~ei.attacked_by(Us);
807 b2 = b & ei.attacked_by(Them, QUEEN);
809 attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b2);
812 b2 = b & ei.attacked_by(Them, ROOK);
814 attackUnits += RookCheckBonus * count_1s_max_15<HasPopCnt>(b2);
816 if (QueenCheckBonus > 0 || BishopCheckBonus > 0)
818 b = pos.attacks_from<BISHOP>(s) & ~pos.pieces_of_color(Them) & ~ei.attacked_by(Us);
821 b2 = b & ei.attacked_by(Them, QUEEN);
823 attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b2);
826 b2 = b & ei.attacked_by(Them, BISHOP);
828 attackUnits += BishopCheckBonus * count_1s_max_15<HasPopCnt>(b2);
830 if (KnightCheckBonus > 0)
832 b = pos.attacks_from<KNIGHT>(s) & ~pos.pieces_of_color(Them) & ~ei.attacked_by(Us);
835 b2 = b & ei.attacked_by(Them, KNIGHT);
837 attackUnits += KnightCheckBonus * count_1s_max_15<HasPopCnt>(b2);
840 // Analyse discovered checks (only for non-pawns right now, consider
841 // adding pawns later).
842 if (DiscoveredCheckBonus)
844 b = pos.discovered_check_candidates(Them) & ~pos.pieces(PAWN);
846 attackUnits += DiscoveredCheckBonus * count_1s_max_15<HasPopCnt>(b) * (sente ? 2 : 1);
849 // Has a mate threat been found? We don't do anything here if the
850 // side with the mating move is the side to move, because in that
851 // case the mating side will get a huge bonus at the end of the main
852 // evaluation function instead.
853 if (ei.mateThreat[Them] != MOVE_NONE)
854 attackUnits += MateThreatBonus;
856 // Ensure that attackUnits is between 0 and 99, in order to avoid array
857 // out of bounds errors:
861 if (attackUnits >= 100)
864 // Finally, extract the king safety score from the SafetyTable[] array.
865 // Add the score to the evaluation, and also to ei.futilityMargin. The
866 // reason for adding the king safety score to the futility margin is
867 // that the king safety scores can sometimes be very big, and that
868 // capturing a single attacking piece can therefore result in a score
869 // change far bigger than the value of the captured piece.
870 Value v = apply_weight(SafetyTable[attackUnits], WeightKingSafety[Us]);
872 ei.mgValue -= Sign[Us] * v;
874 if (Us == pos.side_to_move())
875 ei.futilityMargin += v;
880 // evaluate_passed_pawns() evaluates the passed pawns for both sides
882 void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
884 bool hasUnstoppable[2] = {false, false};
885 int movesToGo[2] = {100, 100};
887 for (Color us = WHITE; us <= BLACK; us++)
889 Color them = opposite_color(us);
890 Square ourKingSq = pos.king_square(us);
891 Square theirKingSq = pos.king_square(them);
892 Bitboard b = ei.pi->passed_pawns() & pos.pieces(PAWN, us), b2, b3, b4;
896 Square s = pop_1st_bit(&b);
898 assert(pos.piece_on(s) == piece_of_color_and_type(us, PAWN));
899 assert(pos.pawn_is_passed(us, s));
901 int r = int(relative_rank(us, s) - RANK_2);
902 int tr = Max(0, r * (r - 1));
903 Square blockSq = s + pawn_push(us);
905 // Base bonus based on rank
906 Value mbonus = Value(20 * tr);
907 Value ebonus = Value(10 + r * r * 10);
909 // Adjust bonus based on king proximity
912 ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr);
913 ebonus -= Value(square_distance(ourKingSq, blockSq + pawn_push(us)) * 1 * tr);
914 ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr);
916 // If the pawn is free to advance, increase bonus
917 if (pos.square_is_empty(blockSq))
919 b2 = squares_in_front_of(us, s);
920 b3 = b2 & ei.attacked_by(them);
921 b4 = b2 & ei.attacked_by(us);
923 // If there is an enemy rook or queen attacking the pawn from behind,
924 // add all X-ray attacks by the rook or queen.
925 if ( bit_is_set(ei.attacked_by(them,ROOK) | ei.attacked_by(them,QUEEN),s)
926 && (squares_behind(us, s) & pos.pieces(ROOK, QUEEN, them)))
929 // Squares attacked or occupied by enemy pieces
930 b3 |= (b2 & pos.pieces_of_color(them));
932 // There are no enemy pawns in the pawn's path
933 assert((b2 & pos.pieces(PAWN, them)) == EmptyBoardBB);
935 // Are any of the squares in the pawn's path attacked or occupied by the enemy?
936 if (b3 == EmptyBoardBB)
937 // No enemy attacks or pieces, huge bonus!
938 ebonus += Value(tr * (b2 == b4 ? 17 : 15));
940 // OK, there are enemy attacks or pieces (but not pawns). Are those
941 // squares which are attacked by the enemy also attacked by us?
942 // If yes, big bonus (but smaller than when there are no enemy attacks),
943 // if no, somewhat smaller bonus.
944 ebonus += Value(tr * ((b3 & b4) == b3 ? 13 : 8));
946 // At last, add a small bonus when there are no *friendly* pieces
947 // in the pawn's path.
948 if ((b2 & pos.pieces_of_color(us)) == EmptyBoardBB)
953 // If the pawn is supported by a friendly pawn, increase bonus
954 b2 = pos.pieces(PAWN, us) & neighboring_files_bb(s);
956 ebonus += Value(r * 20);
957 else if (pos.attacks_from<PAWN>(s, them) & b2)
958 ebonus += Value(r * 12);
960 // If the other side has only a king, check whether the pawn is
962 if (pos.non_pawn_material(them) == Value(0))
967 qsq = relative_square(us, make_square(square_file(s), RANK_8));
968 d = square_distance(s, qsq)
969 - square_distance(theirKingSq, qsq)
970 + (us != pos.side_to_move());
974 int mtg = RANK_8 - relative_rank(us, s);
975 int blockerCount = count_1s_max_15(squares_in_front_of(us,s) & pos.occupied_squares());
980 hasUnstoppable[us] = true;
981 movesToGo[us] = Min(movesToGo[us], mtg);
985 // Rook pawns are a special case: They are sometimes worse, and
986 // sometimes better than other passed pawns. It is difficult to find
987 // good rules for determining whether they are good or bad. For now,
988 // we try the following: Increase the value for rook pawns if the
989 // other side has no pieces apart from a knight, and decrease the
990 // value if the other side has a rook or queen.
991 if (square_file(s) == FILE_A || square_file(s) == FILE_H)
993 if ( pos.non_pawn_material(them) <= KnightValueMidgame
994 && pos.piece_count(them, KNIGHT) <= 1)
995 ebonus += ebonus / 4;
996 else if (pos.pieces(ROOK, QUEEN, them))
997 ebonus -= ebonus / 4;
1000 // Add the scores for this pawn to the middle game and endgame eval.
1001 ei.mgValue += apply_weight(Sign[us] * mbonus, WeightPassedPawnsMidgame);
1002 ei.egValue += apply_weight(Sign[us] * ebonus, WeightPassedPawnsEndgame);
1006 // Does either side have an unstoppable passed pawn?
1007 if (hasUnstoppable[WHITE] && !hasUnstoppable[BLACK])
1008 ei.egValue += UnstoppablePawnValue - Value(0x40 * movesToGo[WHITE]);
1009 else if (hasUnstoppable[BLACK] && !hasUnstoppable[WHITE])
1010 ei.egValue -= UnstoppablePawnValue - Value(0x40 * movesToGo[BLACK]);
1011 else if (hasUnstoppable[BLACK] && hasUnstoppable[WHITE])
1013 // Both sides have unstoppable pawns! Try to find out who queens
1014 // first. We begin by transforming 'movesToGo' to the number of
1015 // plies until the pawn queens for both sides.
1016 movesToGo[WHITE] *= 2;
1017 movesToGo[BLACK] *= 2;
1018 movesToGo[pos.side_to_move()]--;
1020 // If one side queens at least three plies before the other, that
1022 if (movesToGo[WHITE] <= movesToGo[BLACK] - 3)
1023 ei.egValue += UnstoppablePawnValue - Value(0x40 * (movesToGo[WHITE]/2));
1024 else if (movesToGo[BLACK] <= movesToGo[WHITE] - 3)
1025 ei.egValue -= UnstoppablePawnValue - Value(0x40 * (movesToGo[BLACK]/2));
1027 // We could also add some rules about the situation when one side
1028 // queens exactly one ply before the other: Does the first queen
1029 // check the opponent's king, or attack the opponent's queening square?
1030 // This is slightly tricky to get right, because it is possible that
1031 // the opponent's king has moved somewhere before the first pawn queens.
1036 // evaluate_trapped_bishop_a7h7() determines whether a bishop on a7/h7
1037 // (a2/h2 for black) is trapped by enemy pawns, and assigns a penalty
1040 void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo &ei) {
1042 assert(square_is_ok(s));
1043 assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
1045 Square b6 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B6 : SQ_G6);
1046 Square b8 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B8 : SQ_G8);
1048 if ( pos.piece_on(b6) == piece_of_color_and_type(opposite_color(us), PAWN)
1049 && pos.see(s, b6) < 0
1050 && pos.see(s, b8) < 0)
1052 ei.mgValue -= Sign[us] * TrappedBishopA7H7Penalty;
1053 ei.egValue -= Sign[us] * TrappedBishopA7H7Penalty;
1058 // evaluate_trapped_bishop_a1h1() determines whether a bishop on a1/h1
1059 // (a8/h8 for black) is trapped by a friendly pawn on b2/g2 (b7/g7 for
1060 // black), and assigns a penalty if it is. This pattern can obviously
1061 // only occur in Chess960 games.
1063 void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei) {
1065 Piece pawn = piece_of_color_and_type(us, PAWN);
1069 assert(square_is_ok(s));
1070 assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
1072 if (square_file(s) == FILE_A)
1074 b2 = relative_square(us, SQ_B2);
1075 b3 = relative_square(us, SQ_B3);
1076 c3 = relative_square(us, SQ_C3);
1080 b2 = relative_square(us, SQ_G2);
1081 b3 = relative_square(us, SQ_G3);
1082 c3 = relative_square(us, SQ_F3);
1085 if (pos.piece_on(b2) == pawn)
1089 if (!pos.square_is_empty(b3))
1090 penalty = 2*TrappedBishopA1H1Penalty;
1091 else if (pos.piece_on(c3) == pawn)
1092 penalty = TrappedBishopA1H1Penalty;
1094 penalty = TrappedBishopA1H1Penalty / 2;
1096 ei.mgValue -= Sign[us] * penalty;
1097 ei.egValue -= Sign[us] * penalty;
1102 // evaluate_space() computes the space evaluation for a given side. The
1103 // space evaluation is a simple bonus based on the number of safe squares
1104 // available for minor pieces on the central four files on ranks 2--4. Safe
1105 // squares one, two or three squares behind a friendly pawn are counted
1106 // twice. Finally, the space bonus is scaled by a weight taken from the
1107 // material hash table.
1108 template<Color Us, bool HasPopCnt>
1109 void evaluate_space(const Position& pos, EvalInfo& ei) {
1111 const Color Them = (Us == WHITE ? BLACK : WHITE);
1113 // Find the safe squares for our pieces inside the area defined by
1114 // SpaceMask[us]. A square is unsafe if it is attacked by an enemy
1115 // pawn, or if it is undefended and attacked by an enemy piece.
1117 Bitboard safeSquares = SpaceMask[Us]
1118 & ~pos.pieces(PAWN, Us)
1119 & ~ei.attacked_by(Them, PAWN)
1120 & ~(~ei.attacked_by(Us) & ei.attacked_by(Them));
1122 // Find all squares which are at most three squares behind some friendly
1124 Bitboard behindFriendlyPawns = pos.pieces(PAWN, Us);
1125 behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 8 : behindFriendlyPawns << 8);
1126 behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 16 : behindFriendlyPawns << 16);
1128 int space = count_1s_max_15<HasPopCnt>(safeSquares)
1129 + count_1s_max_15<HasPopCnt>(behindFriendlyPawns & safeSquares);
1131 ei.mgValue += Sign[Us] * apply_weight(Value(space * ei.mi->space_weight()), WeightSpace);
1135 // apply_weight() applies an evaluation weight to a value
1137 inline Value apply_weight(Value v, int w) {
1138 return (v*w) / 0x100;
1142 // scale_by_game_phase() interpolates between a middle game and an endgame
1143 // score, based on game phase. It also scales the return value by a
1144 // ScaleFactor array.
1146 Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]) {
1148 assert(mv > -VALUE_INFINITE && mv < VALUE_INFINITE);
1149 assert(ev > -VALUE_INFINITE && ev < VALUE_INFINITE);
1150 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1152 ev = apply_scale_factor(ev, sf[(ev > Value(0) ? WHITE : BLACK)]);
1154 Value result = Value(int((mv * ph + ev * (128 - ph)) / 128));
1155 return Value(int(result) & ~(GrainSize - 1));
1159 // weight_option() computes the value of an evaluation weight, by combining
1160 // an UCI-configurable weight with an internal weight.
1162 int weight_option(const std::string& opt, int internalWeight) {
1164 int uciWeight = get_option_value_int(opt);
1165 uciWeight = (uciWeight * 0x100) / 100;
1166 return (uciWeight * internalWeight) / 0x100;
1170 // init_safety() initizes the king safety evaluation, based on UCI
1171 // parameters. It is called from read_weights().
1173 void init_safety() {
1175 QueenContactCheckBonus = get_option_value_int("Queen Contact Check Bonus");
1176 QueenCheckBonus = get_option_value_int("Queen Check Bonus");
1177 RookCheckBonus = get_option_value_int("Rook Check Bonus");
1178 BishopCheckBonus = get_option_value_int("Bishop Check Bonus");
1179 KnightCheckBonus = get_option_value_int("Knight Check Bonus");
1180 DiscoveredCheckBonus = get_option_value_int("Discovered Check Bonus");
1181 MateThreatBonus = get_option_value_int("Mate Threat Bonus");
1183 int maxSlope = get_option_value_int("King Safety Max Slope");
1184 int peak = get_option_value_int("King Safety Max Value") * 256 / 100;
1185 double a = get_option_value_int("King Safety Coefficient") / 100.0;
1186 double b = get_option_value_int("King Safety X Intercept");
1187 bool quad = (get_option_value_string("King Safety Curve") == "Quadratic");
1188 bool linear = (get_option_value_string("King Safety Curve") == "Linear");
1190 for (int i = 0; i < 100; i++)
1193 SafetyTable[i] = Value(0);
1195 SafetyTable[i] = Value((int)(a * (i - b) * (i - b)));
1197 SafetyTable[i] = Value((int)(100 * a * (i - b)));
1200 for (int i = 0; i < 100; i++)
1202 if (SafetyTable[i+1] - SafetyTable[i] > maxSlope)
1203 for (int j = i + 1; j < 100; j++)
1204 SafetyTable[j] = SafetyTable[j-1] + Value(maxSlope);
1206 if (SafetyTable[i] > Value(peak))
1207 SafetyTable[i] = Value(peak);