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 = 4;
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 area of the board which is consdered by
211 // 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 // Array which gives the number of nonzero bits in an 8-bit integer
270 uint8_t BitCount8Bit[256];
272 // Function prototypes
273 template<bool HasPopCnt>
274 Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID);
276 template<PieceType Piece, bool HasPopCnt>
277 void evaluate_pieces(const Position& p, Color us, EvalInfo& ei);
279 template<bool HasPopCnt>
280 void evaluate_king(const Position& p, Color us, 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,
285 void evaluate_trapped_bishop_a1h1(const Position &pos, Square s, Color us,
287 template<bool HasPopCnt>
288 void evaluate_space(const Position &p, Color us, EvalInfo &ei);
289 inline Value apply_weight(Value v, int w);
290 Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]);
292 int compute_weight(int uciWeight, int internalWeight);
293 int weight_option(const std::string& opt, int weight);
303 /// evaluate() is the main evaluation function. It always computes two
304 /// values, an endgame score and a middle game score, and interpolates
305 /// between them based on the remaining material.
306 Value evaluate(const Position& pos, EvalInfo& ei, int threadID) {
308 return CpuHasPOPCNT ? do_evaluate<true>(pos, ei, threadID)
309 : do_evaluate<false>(pos, ei, threadID);
314 template<bool HasPopCnt>
315 Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID) {
318 assert(threadID >= 0 && threadID < THREAD_MAX);
320 memset(&ei, 0, sizeof(EvalInfo));
322 // Initialize by reading the incrementally updated scores included in the
323 // position object (material + piece square tables)
324 ei.mgValue = pos.mg_value();
325 ei.egValue = pos.eg_value();
327 // Probe the material hash table
328 ei.mi = MaterialTable[threadID]->get_material_info(pos);
329 ei.mgValue += ei.mi->material_value();
330 ei.egValue += ei.mi->material_value();
332 // If we have a specialized evaluation function for the current material
333 // configuration, call it and return
334 if (ei.mi->specialized_eval_exists())
335 return ei.mi->evaluate(pos);
337 // After get_material_info() call that modifies them
338 ScaleFactor factor[2];
339 factor[WHITE] = ei.mi->scale_factor(pos, WHITE);
340 factor[BLACK] = ei.mi->scale_factor(pos, BLACK);
342 // Probe the pawn hash table
343 ei.pi = PawnTable[threadID]->get_pawn_info(pos);
344 ei.mgValue += apply_weight(ei.pi->mg_value(), WeightPawnStructureMidgame);
345 ei.egValue += apply_weight(ei.pi->eg_value(), WeightPawnStructureEndgame);
347 // Initialize king attack bitboards and king attack zones for both sides
348 ei.attackedBy[WHITE][KING] = pos.piece_attacks<KING>(pos.king_square(WHITE));
349 ei.attackedBy[BLACK][KING] = pos.piece_attacks<KING>(pos.king_square(BLACK));
350 ei.kingZone[WHITE] = ei.attackedBy[BLACK][KING] | (ei.attackedBy[BLACK][KING] >> 8);
351 ei.kingZone[BLACK] = ei.attackedBy[WHITE][KING] | (ei.attackedBy[WHITE][KING] << 8);
353 // Initialize pawn attack bitboards for both sides
354 ei.attackedBy[WHITE][PAWN] = ((pos.pawns(WHITE) << 9) & ~FileABB) | ((pos.pawns(WHITE) << 7) & ~FileHBB);
355 ei.attackedBy[BLACK][PAWN] = ((pos.pawns(BLACK) >> 7) & ~FileABB) | ((pos.pawns(BLACK) >> 9) & ~FileHBB);
356 Bitboard b1 = ei.attackedBy[WHITE][PAWN] & ei.attackedBy[BLACK][KING];
357 Bitboard b2 = ei.attackedBy[BLACK][PAWN] & ei.attackedBy[WHITE][KING];
359 ei.kingAttackersCount[WHITE] = count_1s_max_15<HasPopCnt>(b1)/2;
362 ei.kingAttackersCount[BLACK] = count_1s_max_15<HasPopCnt>(b2)/2;
365 for (Color c = WHITE; c <= BLACK; c++)
367 evaluate_pieces<KNIGHT, HasPopCnt>(pos, c, ei);
368 evaluate_pieces<BISHOP, HasPopCnt>(pos, c, ei);
369 evaluate_pieces<ROOK, HasPopCnt>(pos, c, ei);
370 evaluate_pieces<QUEEN, HasPopCnt>(pos, c, ei);
372 // Sum up all attacked squares
373 ei.attackedBy[c][0] = ei.attackedBy[c][PAWN] | ei.attackedBy[c][KNIGHT]
374 | ei.attackedBy[c][BISHOP] | ei.attackedBy[c][ROOK]
375 | ei.attackedBy[c][QUEEN] | ei.attackedBy[c][KING];
378 // Kings. Kings are evaluated after all other pieces for both sides,
379 // because we need complete attack information for all pieces when computing
380 // the king safety evaluation.
381 for (Color c = WHITE; c <= BLACK; c++)
382 evaluate_king<HasPopCnt>(pos, c, ei);
384 // Evaluate passed pawns. We evaluate passed pawns for both sides at once,
385 // because we need to know which side promotes first in positions where
386 // both sides have an unstoppable passed pawn.
387 if (ei.pi->passed_pawns())
388 evaluate_passed_pawns(pos, ei);
390 Phase phase = pos.game_phase();
392 // Middle-game specific evaluation terms
393 if (phase > PHASE_ENDGAME)
395 // Pawn storms in positions with opposite castling.
396 if ( square_file(pos.king_square(WHITE)) >= FILE_E
397 && square_file(pos.king_square(BLACK)) <= FILE_D)
399 ei.mgValue += ei.pi->queenside_storm_value(WHITE)
400 - ei.pi->kingside_storm_value(BLACK);
402 else if ( square_file(pos.king_square(WHITE)) <= FILE_D
403 && square_file(pos.king_square(BLACK)) >= FILE_E)
405 ei.mgValue += ei.pi->kingside_storm_value(WHITE)
406 - ei.pi->queenside_storm_value(BLACK);
408 // Evaluate space for both sides
409 if (ei.mi->space_weight() > 0)
411 evaluate_space<HasPopCnt>(pos, WHITE, ei);
412 evaluate_space<HasPopCnt>(pos, BLACK, ei);
417 ei.mgValue += apply_weight(ei.mgMobility, WeightMobilityMidgame);
418 ei.egValue += apply_weight(ei.egMobility, WeightMobilityEndgame);
420 // If we don't already have an unusual scale factor, check for opposite
421 // colored bishop endgames, and use a lower scale for those
422 if ( phase < PHASE_MIDGAME
423 && pos.opposite_colored_bishops()
424 && ( (factor[WHITE] == SCALE_FACTOR_NORMAL && ei.egValue > Value(0))
425 || (factor[BLACK] == SCALE_FACTOR_NORMAL && ei.egValue < Value(0))))
429 // Only the two bishops ?
430 if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
431 && pos.non_pawn_material(BLACK) == BishopValueMidgame)
433 // Check for KBP vs KB with only a single pawn that is almost
434 // certainly a draw or at least two pawns.
435 bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
436 sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
439 // Endgame with opposite-colored bishops, but also other pieces. Still
440 // a bit drawish, but not as drawish as with only the two bishops.
441 sf = ScaleFactor(50);
443 if (factor[WHITE] == SCALE_FACTOR_NORMAL)
445 if (factor[BLACK] == SCALE_FACTOR_NORMAL)
449 // Interpolate between the middle game and the endgame score, and
451 Color stm = pos.side_to_move();
453 Value v = Sign[stm] * scale_by_game_phase(ei.mgValue, ei.egValue, phase, factor);
455 return (ei.mateThreat[stm] == MOVE_NONE ? v : 8 * QueenValueMidgame - v);
460 /// quick_evaluate() does a very approximate evaluation of the current position.
461 /// It currently considers only material and piece square table scores. Perhaps
462 /// we should add scores from the pawn and material hash tables?
464 Value quick_evaluate(const Position &pos) {
469 ScaleFactor sf[2] = {SCALE_FACTOR_NORMAL, SCALE_FACTOR_NORMAL};
471 Value mgv = pos.mg_value();
472 Value egv = pos.eg_value();
473 Phase ph = pos.game_phase();
474 Color stm = pos.side_to_move();
476 return Sign[stm] * scale_by_game_phase(mgv, egv, ph, sf);
480 /// init_eval() initializes various tables used by the evaluation function.
482 void init_eval(int threads) {
484 assert(threads <= THREAD_MAX);
486 for (int i = 0; i < THREAD_MAX; i++)
491 delete MaterialTable[i];
493 MaterialTable[i] = NULL;
497 PawnTable[i] = new PawnInfoTable(PawnTableSize);
498 if (!MaterialTable[i])
499 MaterialTable[i] = new MaterialInfoTable(MaterialTableSize);
502 for (Bitboard b = 0ULL; b < 256ULL; b++)
504 assert(count_1s(b) == int(uint8_t(count_1s(b))));
505 BitCount8Bit[b] = (uint8_t)count_1s(b);
510 /// quit_eval() releases heap-allocated memory at program termination.
514 for (int i = 0; i < THREAD_MAX; i++)
517 delete MaterialTable[i];
519 MaterialTable[i] = NULL;
524 /// read_weights() reads evaluation weights from the corresponding UCI
527 void read_weights(Color us) {
529 WeightMobilityMidgame = weight_option("Mobility (Middle Game)", WeightMobilityMidgameInternal);
530 WeightMobilityEndgame = weight_option("Mobility (Endgame)", WeightMobilityEndgameInternal);
531 WeightPawnStructureMidgame = weight_option("Pawn Structure (Middle Game)", WeightPawnStructureMidgameInternal);
532 WeightPawnStructureEndgame = weight_option("Pawn Structure (Endgame)", WeightPawnStructureEndgameInternal);
533 WeightPassedPawnsMidgame = weight_option("Passed Pawns (Middle Game)", WeightPassedPawnsMidgameInternal);
534 WeightPassedPawnsEndgame = weight_option("Passed Pawns (Endgame)", WeightPassedPawnsEndgameInternal);
536 Color them = opposite_color(us);
538 WeightKingSafety[us] = weight_option("Cowardice", WeightKingSafetyInternal);
539 WeightKingSafety[them] = weight_option("Aggressiveness", WeightKingOppSafetyInternal);
540 // If running in analysis mode, make sure we use symmetrical king safety.
541 // We do this by replacing both WeightKingSafety[us] and
542 // WeightKingSafety[them] by their average.
543 if (get_option_value_bool("UCI_AnalyseMode")) {
544 WeightKingSafety[us] = (WeightKingSafety[us] + WeightKingSafety[them]) / 2;
545 WeightKingSafety[them] = WeightKingSafety[us];
548 WeightSpace = weight_option("Space", WeightSpaceInternal);
556 // evaluate_mobility() computes mobility and attacks for every piece
558 template<PieceType Piece, bool HasPopCnt>
559 int evaluate_mobility(const Position& p, const Bitboard& b, Color us, Color them, EvalInfo& ei) {
561 static const int AttackWeight[] = { 0, 0, KnightAttackWeight, BishopAttackWeight, RookAttackWeight, QueenAttackWeight };
562 static const Value* MgBonus[] = { 0, 0, MidgameKnightMobilityBonus, MidgameBishopMobilityBonus, MidgameRookMobilityBonus, MidgameQueenMobilityBonus };
563 static const Value* EgBonus[] = { 0, 0, EndgameKnightMobilityBonus, EndgameBishopMobilityBonus, EndgameRookMobilityBonus, EndgameQueenMobilityBonus };
565 // Update attack info
566 ei.attackedBy[us][Piece] |= b;
569 if (b & ei.kingZone[us])
571 ei.kingAttackersCount[us]++;
572 ei.kingAttackersWeight[us] += AttackWeight[Piece];
573 Bitboard bb = (b & ei.attackedBy[them][KING]);
575 ei.kingAdjacentZoneAttacksCount[us] += count_1s_max_15<HasPopCnt>(bb);
578 // Remove squares protected by enemy pawns
579 Bitboard bb = (b & ~ei.attackedBy[them][PAWN]);
582 int mob = (Piece != QUEEN ? count_1s_max_15<HasPopCnt>(bb & ~p.pieces_of_color(us))
583 : count_1s<HasPopCnt>(bb & ~p.pieces_of_color(us)));
585 ei.mgMobility += Sign[us] * MgBonus[Piece][mob];
586 ei.egMobility += Sign[us] * EgBonus[Piece][mob];
591 // evaluate_outposts() evaluates bishop and knight outposts squares
593 template<PieceType Piece>
594 void evaluate_outposts(const Position& p, Color us, Color them, EvalInfo& ei, Square s) {
596 // Initial bonus based on square
597 Value bonus = (Piece == BISHOP ? BishopOutpostBonus[relative_square(us, s)]
598 : KnightOutpostBonus[relative_square(us, s)]);
600 // Increase bonus if supported by pawn, especially if the opponent has
601 // no minor piece which can exchange the outpost piece
602 if (bonus && (p.pawn_attacks(them, s) & p.pawns(us)))
604 if ( p.knights(them) == EmptyBoardBB
605 && (SquaresByColorBB[square_color(s)] & p.bishops(them)) == EmptyBoardBB)
606 bonus += bonus + bonus / 2;
610 ei.mgValue += Sign[us] * bonus;
611 ei.egValue += Sign[us] * bonus;
615 // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given
618 template<PieceType Piece, bool HasPopCnt>
619 void evaluate_pieces(const Position& pos, Color us, EvalInfo& ei) {
625 Color them = opposite_color(us);
627 for (int i = 0, e = pos.piece_count(us, Piece); i < e; i++)
629 s = pos.piece_list(us, Piece, i);
631 if (Piece == KNIGHT || Piece == QUEEN)
632 b = pos.piece_attacks<Piece>(s);
633 else if (Piece == BISHOP)
634 b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.queens(us));
635 else if (Piece == ROOK)
636 b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.rooks_and_queens(us));
640 // Attacks and mobility
641 mob = evaluate_mobility<Piece, HasPopCnt>(pos, b, us, them, ei);
643 // Bishop and knight outposts squares
644 if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, them))
645 evaluate_outposts<Piece>(pos, us, them, ei, s);
647 // Special patterns: trapped bishops on a7/h7/a2/h2
648 // and trapped bishops on a1/h1/a8/h8 in Chess960.
651 if (bit_is_set(MaskA7H7[us], s))
652 evaluate_trapped_bishop_a7h7(pos, s, us, ei);
654 if (Chess960 && bit_is_set(MaskA1H1[us], s))
655 evaluate_trapped_bishop_a1h1(pos, s, us, ei);
658 if (Piece == ROOK || Piece == QUEEN)
660 // Queen or rook on 7th rank
661 if ( relative_rank(us, s) == RANK_7
662 && relative_rank(us, pos.king_square(them)) == RANK_8)
664 ei.mgValue += Sign[us] * (Piece == ROOK ? MidgameRookOn7thBonus : MidgameQueenOn7thBonus);
665 ei.egValue += Sign[us] * (Piece == ROOK ? EndgameRookOn7thBonus : EndgameQueenOn7thBonus);
669 // Special extra evaluation for rooks
672 // Open and half-open files
674 if (ei.pi->file_is_half_open(us, f))
676 if (ei.pi->file_is_half_open(them, f))
678 ei.mgValue += Sign[us] * RookOpenFileBonus;
679 ei.egValue += Sign[us] * RookOpenFileBonus;
683 ei.mgValue += Sign[us] * RookHalfOpenFileBonus;
684 ei.egValue += Sign[us] * RookHalfOpenFileBonus;
688 // Penalize rooks which are trapped inside a king. Penalize more if
689 // king has lost right to castle.
690 if (mob > 6 || ei.pi->file_is_half_open(us, f))
693 ksq = pos.king_square(us);
695 if ( square_file(ksq) >= FILE_E
696 && square_file(s) > square_file(ksq)
697 && (relative_rank(us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
699 // Is there a half-open file between the king and the edge of the board?
700 if (!ei.pi->has_open_file_to_right(us, square_file(ksq)))
701 ei.mgValue -= pos.can_castle(us)? Sign[us] * ((TrappedRookPenalty - mob * 16) / 2)
702 : Sign[us] * (TrappedRookPenalty - mob * 16);
704 else if ( square_file(ksq) <= FILE_D
705 && square_file(s) < square_file(ksq)
706 && (relative_rank(us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
708 // Is there a half-open file between the king and the edge of the board?
709 if (!ei.pi->has_open_file_to_left(us, square_file(ksq)))
710 ei.mgValue -= pos.can_castle(us)? Sign[us] * ((TrappedRookPenalty - mob * 16) / 2)
711 : Sign[us] * (TrappedRookPenalty - mob * 16);
717 inline Bitboard shiftRowsDown(const Bitboard& b, int num) {
719 return b >> (num << 3);
722 // evaluate_king<>() assigns bonuses and penalties to a king of a given color.
724 template<bool HasPopCnt>
725 void evaluate_king(const Position& p, Color us, EvalInfo& ei) {
727 int shelter = 0, sign = Sign[us];
728 Square s = p.king_square(us);
731 if (relative_rank(us, s) <= RANK_4)
733 // Shelter cache lookup
734 shelter = ei.pi->kingShelter(us, s);
738 Bitboard pawns = p.pawns(us) & this_and_neighboring_files_bb(s);
739 Rank r = square_rank(s);
740 for (int i = 1; i < 4; i++)
741 shelter += BitCount8Bit[shiftRowsDown(pawns, r+i*sign) & 0xFF] * (128 >> i);
743 // Cache shelter value in pawn info
744 ei.pi->setKingShelter(us, s, shelter);
746 ei.mgValue += sign * Value(shelter);
749 // King safety. This is quite complicated, and is almost certainly far
750 // from optimally tuned.
751 Color them = opposite_color(us);
753 if ( p.piece_count(them, QUEEN) >= 1
754 && ei.kingAttackersCount[them] >= 2
755 && p.non_pawn_material(them) >= QueenValueMidgame + RookValueMidgame
756 && ei.kingAdjacentZoneAttacksCount[them])
758 // Is it the attackers turn to move?
759 bool sente = (them == p.side_to_move());
761 // Find the attacked squares around the king which has no defenders
762 // apart from the king itself
763 Bitboard undefended =
764 ei.attacked_by(them) & ~ei.attacked_by(us, PAWN)
765 & ~ei.attacked_by(us, KNIGHT) & ~ei.attacked_by(us, BISHOP)
766 & ~ei.attacked_by(us, ROOK) & ~ei.attacked_by(us, QUEEN)
767 & ei.attacked_by(us, KING);
769 Bitboard occ = p.occupied_squares(), b, b2;
771 // Initialize the 'attackUnits' variable, which is used later on as an
772 // index to the SafetyTable[] array. The initial value is based on the
773 // number and types of the attacking pieces, the number of attacked and
774 // undefended squares around the king, the square of the king, and the
775 // quality of the pawn shelter.
777 Min((ei.kingAttackersCount[them] * ei.kingAttackersWeight[them]) / 2, 25)
778 + (ei.kingAdjacentZoneAttacksCount[them] + count_1s_max_15<HasPopCnt>(undefended)) * 3
779 + InitKingDanger[relative_square(us, s)] - (shelter >> 5);
781 // Analyse safe queen contact checks
782 b = undefended & ei.attacked_by(them, QUEEN) & ~p.pieces_of_color(them);
785 Bitboard attackedByOthers =
786 ei.attacked_by(them, PAWN) | ei.attacked_by(them, KNIGHT)
787 | ei.attacked_by(them, BISHOP) | ei.attacked_by(them, ROOK);
789 b &= attackedByOthers;
792 // The bitboard b now contains the squares available for safe queen
794 int count = count_1s_max_15<HasPopCnt>(b);
795 attackUnits += QueenContactCheckBonus * count * (sente ? 2 : 1);
797 // Is there a mate threat?
798 if (QueenContactMates && !p.is_check())
800 Bitboard escapeSquares =
801 p.piece_attacks<KING>(s) & ~p.pieces_of_color(us) & ~attackedByOthers;
805 Square from, to = pop_1st_bit(&b);
806 if (!(escapeSquares & ~queen_attacks_bb(to, occ & ClearMaskBB[s])))
808 // We have a mate, unless the queen is pinned or there
809 // is an X-ray attack through the queen.
810 for (int i = 0; i < p.piece_count(them, QUEEN); i++)
812 from = p.piece_list(them, QUEEN, i);
813 if ( bit_is_set(p.piece_attacks<QUEEN>(from), to)
814 && !bit_is_set(p.pinned_pieces(them), from)
815 && !(rook_attacks_bb(to, occ & ClearMaskBB[from]) & p.rooks_and_queens(us))
816 && !(bishop_attacks_bb(to, occ & ClearMaskBB[from]) & p.bishops_and_queens(us)))
818 ei.mateThreat[them] = make_move(from, to);
826 // Analyse safe distance checks
827 if (QueenCheckBonus > 0 || RookCheckBonus > 0)
829 b = p.piece_attacks<ROOK>(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
832 b2 = b & ei.attacked_by(them, QUEEN);
834 attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b2);
837 b2 = b & ei.attacked_by(them, ROOK);
839 attackUnits += RookCheckBonus * count_1s_max_15<HasPopCnt>(b2);
841 if (QueenCheckBonus > 0 || BishopCheckBonus > 0)
843 b = p.piece_attacks<BISHOP>(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
846 b2 = b & ei.attacked_by(them, QUEEN);
848 attackUnits += QueenCheckBonus * count_1s_max_15<HasPopCnt>(b2);
851 b2 = b & ei.attacked_by(them, BISHOP);
853 attackUnits += BishopCheckBonus * count_1s_max_15<HasPopCnt>(b2);
855 if (KnightCheckBonus > 0)
857 b = p.piece_attacks<KNIGHT>(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
860 b2 = b & ei.attacked_by(them, KNIGHT);
862 attackUnits += KnightCheckBonus * count_1s_max_15<HasPopCnt>(b2);
865 // Analyse discovered checks (only for non-pawns right now, consider
866 // adding pawns later).
867 if (DiscoveredCheckBonus)
869 b = p.discovered_check_candidates(them) & ~p.pawns();
871 attackUnits += DiscoveredCheckBonus * count_1s_max_15<HasPopCnt>(b) * (sente? 2 : 1);
874 // Has a mate threat been found? We don't do anything here if the
875 // side with the mating move is the side to move, because in that
876 // case the mating side will get a huge bonus at the end of the main
877 // evaluation function instead.
878 if (ei.mateThreat[them] != MOVE_NONE)
879 attackUnits += MateThreatBonus;
881 // Ensure that attackUnits is between 0 and 99, in order to avoid array
882 // out of bounds errors:
886 if (attackUnits >= 100)
889 // Finally, extract the king safety score from the SafetyTable[] array.
890 // Add the score to the evaluation, and also to ei.futilityMargin. The
891 // reason for adding the king safety score to the futility margin is
892 // that the king safety scores can sometimes be very big, and that
893 // capturing a single attacking piece can therefore result in a score
894 // change far bigger than the value of the captured piece.
895 Value v = apply_weight(SafetyTable[attackUnits], WeightKingSafety[us]);
897 ei.mgValue -= sign * v;
899 if (us == p.side_to_move())
900 ei.futilityMargin += v;
905 // evaluate_passed_pawns() evaluates the passed pawns for both sides.
907 void evaluate_passed_pawns(const Position &pos, EvalInfo &ei) {
909 bool hasUnstoppable[2] = {false, false};
910 int movesToGo[2] = {100, 100};
912 for (Color us = WHITE; us <= BLACK; us++)
914 Color them = opposite_color(us);
915 Square ourKingSq = pos.king_square(us);
916 Square theirKingSq = pos.king_square(them);
917 Bitboard b = ei.pi->passed_pawns() & pos.pawns(us), b2, b3, b4;
921 Square s = pop_1st_bit(&b);
923 assert(pos.piece_on(s) == piece_of_color_and_type(us, PAWN));
924 assert(pos.pawn_is_passed(us, s));
926 int r = int(relative_rank(us, s) - RANK_2);
927 int tr = Max(0, r * (r - 1));
928 Square blockSq = s + pawn_push(us);
930 // Base bonus based on rank
931 Value mbonus = Value(20 * tr);
932 Value ebonus = Value(10 + r * r * 10);
934 // Adjust bonus based on king proximity
937 ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr);
938 ebonus -= Value(square_distance(ourKingSq, blockSq + pawn_push(us)) * 1 * tr);
939 ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr);
941 // If the pawn is free to advance, increase bonus
942 if (pos.square_is_empty(blockSq))
944 b2 = squares_in_front_of(us, s);
945 b3 = b2 & ei.attacked_by(them);
946 b4 = b2 & ei.attacked_by(us);
948 // If there is an enemy rook or queen attacking the pawn from behind,
949 // add all X-ray attacks by the rook or queen.
950 if ( bit_is_set(ei.attacked_by(them,ROOK) | ei.attacked_by(them,QUEEN),s)
951 && (squares_behind(us, s) & pos.rooks_and_queens(them)))
954 // Squares attacked or occupied by enemy pieces
955 b3 |= (b2 & pos.pieces_of_color(them));
957 // There are no enemy pawns in the pawn's path
958 assert((b2 & pos.pieces_of_color_and_type(them, PAWN)) == EmptyBoardBB);
960 // Are any of the squares in the pawn's path attacked or occupied by the enemy?
961 if (b3 == EmptyBoardBB)
962 // No enemy attacks or pieces, huge bonus!
963 ebonus += Value(tr * (b2 == b4 ? 17 : 15));
965 // OK, there are enemy attacks or pieces (but not pawns). Are those
966 // squares which are attacked by the enemy also attacked by us?
967 // If yes, big bonus (but smaller than when there are no enemy attacks),
968 // if no, somewhat smaller bonus.
969 ebonus += Value(tr * ((b3 & b4) == b3 ? 13 : 8));
971 // At last, add a small bonus when there are no *friendly* pieces
972 // in the pawn's path.
973 if ((b2 & pos.pieces_of_color(us)) == EmptyBoardBB)
978 // If the pawn is supported by a friendly pawn, increase bonus
979 b2 = pos.pawns(us) & neighboring_files_bb(s);
981 ebonus += Value(r * 20);
982 else if (pos.pawn_attacks(them, s) & b2)
983 ebonus += Value(r * 12);
985 // If the other side has only a king, check whether the pawn is
987 if (pos.non_pawn_material(them) == Value(0))
992 qsq = relative_square(us, make_square(square_file(s), RANK_8));
993 d = square_distance(s, qsq)
994 - square_distance(theirKingSq, qsq)
995 + (us != pos.side_to_move());
999 int mtg = RANK_8 - relative_rank(us, s);
1000 int blockerCount = count_1s_max_15(squares_in_front_of(us,s) & pos.occupied_squares());
1001 mtg += blockerCount;
1005 hasUnstoppable[us] = true;
1006 movesToGo[us] = Min(movesToGo[us], mtg);
1010 // Rook pawns are a special case: They are sometimes worse, and
1011 // sometimes better than other passed pawns. It is difficult to find
1012 // good rules for determining whether they are good or bad. For now,
1013 // we try the following: Increase the value for rook pawns if the
1014 // other side has no pieces apart from a knight, and decrease the
1015 // value if the other side has a rook or queen.
1016 if (square_file(s) == FILE_A || square_file(s) == FILE_H)
1018 if ( pos.non_pawn_material(them) <= KnightValueMidgame
1019 && pos.piece_count(them, KNIGHT) <= 1)
1020 ebonus += ebonus / 4;
1021 else if (pos.rooks_and_queens(them))
1022 ebonus -= ebonus / 4;
1025 // Add the scores for this pawn to the middle game and endgame eval.
1026 ei.mgValue += apply_weight(Sign[us] * mbonus, WeightPassedPawnsMidgame);
1027 ei.egValue += apply_weight(Sign[us] * ebonus, WeightPassedPawnsEndgame);
1031 // Does either side have an unstoppable passed pawn?
1032 if (hasUnstoppable[WHITE] && !hasUnstoppable[BLACK])
1033 ei.egValue += UnstoppablePawnValue - Value(0x40 * movesToGo[WHITE]);
1034 else if (hasUnstoppable[BLACK] && !hasUnstoppable[WHITE])
1035 ei.egValue -= UnstoppablePawnValue - Value(0x40 * movesToGo[BLACK]);
1036 else if (hasUnstoppable[BLACK] && hasUnstoppable[WHITE])
1038 // Both sides have unstoppable pawns! Try to find out who queens
1039 // first. We begin by transforming 'movesToGo' to the number of
1040 // plies until the pawn queens for both sides.
1041 movesToGo[WHITE] *= 2;
1042 movesToGo[BLACK] *= 2;
1043 movesToGo[pos.side_to_move()]--;
1045 // If one side queens at least three plies before the other, that
1047 if (movesToGo[WHITE] <= movesToGo[BLACK] - 3)
1048 ei.egValue += UnstoppablePawnValue - Value(0x40 * (movesToGo[WHITE]/2));
1049 else if(movesToGo[BLACK] <= movesToGo[WHITE] - 3)
1050 ei.egValue -= UnstoppablePawnValue - Value(0x40 * (movesToGo[BLACK]/2));
1052 // We could also add some rules about the situation when one side
1053 // queens exactly one ply before the other: Does the first queen
1054 // check the opponent's king, or attack the opponent's queening square?
1055 // This is slightly tricky to get right, because it is possible that
1056 // the opponent's king has moved somewhere before the first pawn queens.
1061 // evaluate_trapped_bishop_a7h7() determines whether a bishop on a7/h7
1062 // (a2/h2 for black) is trapped by enemy pawns, and assigns a penalty
1065 void evaluate_trapped_bishop_a7h7(const Position &pos, Square s, Color us,
1067 assert(square_is_ok(s));
1068 assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
1070 Square b6 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B6 : SQ_G6);
1071 Square b8 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B8 : SQ_G8);
1073 if ( pos.piece_on(b6) == piece_of_color_and_type(opposite_color(us), PAWN)
1074 && pos.see(s, b6) < 0
1075 && pos.see(s, b8) < 0)
1077 ei.mgValue -= Sign[us] * TrappedBishopA7H7Penalty;
1078 ei.egValue -= Sign[us] * TrappedBishopA7H7Penalty;
1083 // evaluate_trapped_bishop_a1h1() determines whether a bishop on a1/h1
1084 // (a8/h8 for black) is trapped by a friendly pawn on b2/g2 (b7/g7 for
1085 // black), and assigns a penalty if it is. This pattern can obviously
1086 // only occur in Chess960 games.
1088 void evaluate_trapped_bishop_a1h1(const Position &pos, Square s, Color us,
1090 Piece pawn = piece_of_color_and_type(us, PAWN);
1094 assert(square_is_ok(s));
1095 assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
1097 if (square_file(s) == FILE_A)
1099 b2 = relative_square(us, SQ_B2);
1100 b3 = relative_square(us, SQ_B3);
1101 c3 = relative_square(us, SQ_C3);
1105 b2 = relative_square(us, SQ_G2);
1106 b3 = relative_square(us, SQ_G3);
1107 c3 = relative_square(us, SQ_F3);
1110 if (pos.piece_on(b2) == pawn)
1114 if (!pos.square_is_empty(b3))
1115 penalty = 2*TrappedBishopA1H1Penalty;
1116 else if (pos.piece_on(c3) == pawn)
1117 penalty = TrappedBishopA1H1Penalty;
1119 penalty = TrappedBishopA1H1Penalty / 2;
1121 ei.mgValue -= Sign[us] * penalty;
1122 ei.egValue -= Sign[us] * penalty;
1127 // evaluate_space() computes the space evaluation for a given side. The
1128 // space evaluation is a simple bonus based on the number of safe squares
1129 // available for minor pieces on the central four files on ranks 2--4. Safe
1130 // squares one, two or three squares behind a friendly pawn are counted
1131 // twice. Finally, the space bonus is scaled by a weight taken from the
1132 // material hash table.
1133 template<bool HasPopCnt>
1134 void evaluate_space(const Position &pos, Color us, EvalInfo &ei) {
1136 Color them = opposite_color(us);
1138 // Find the safe squares for our pieces inside the area defined by
1139 // SpaceMask[us]. A square is unsafe it is attacked by an enemy
1140 // pawn, or if it is undefended and attacked by an enemy piece.
1142 Bitboard safeSquares = SpaceMask[us]
1144 & ~ei.attacked_by(them, PAWN)
1145 & ~(~ei.attacked_by(us) & ei.attacked_by(them));
1147 // Find all squares which are at most three squares behind some friendly
1149 Bitboard behindFriendlyPawns = pos.pawns(us);
1152 behindFriendlyPawns |= (behindFriendlyPawns >> 8);
1153 behindFriendlyPawns |= (behindFriendlyPawns >> 16);
1157 behindFriendlyPawns |= (behindFriendlyPawns << 8);
1158 behindFriendlyPawns |= (behindFriendlyPawns << 16);
1161 int space = count_1s_max_15<HasPopCnt>(safeSquares)
1162 + count_1s_max_15<HasPopCnt>(behindFriendlyPawns & safeSquares);
1164 ei.mgValue += Sign[us] * apply_weight(Value(space * ei.mi->space_weight()), WeightSpace);
1168 // apply_weight() applies an evaluation weight to a value
1170 inline Value apply_weight(Value v, int w) {
1171 return (v*w) / 0x100;
1175 // scale_by_game_phase() interpolates between a middle game and an endgame
1176 // score, based on game phase. It also scales the return value by a
1177 // ScaleFactor array.
1179 Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]) {
1181 assert(mv > -VALUE_INFINITE && mv < VALUE_INFINITE);
1182 assert(ev > -VALUE_INFINITE && ev < VALUE_INFINITE);
1183 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1185 ev = apply_scale_factor(ev, sf[(ev > Value(0) ? WHITE : BLACK)]);
1187 Value result = Value(int((mv * ph + ev * (128 - ph)) / 128));
1188 return Value(int(result) & ~(GrainSize - 1));
1192 // compute_weight() computes the value of an evaluation weight, by combining
1193 // an UCI-configurable weight with an internal weight.
1195 int compute_weight(int uciWeight, int internalWeight) {
1197 uciWeight = (uciWeight * 0x100) / 100;
1198 return (uciWeight * internalWeight) / 0x100;
1202 // helper used in read_weights()
1203 int weight_option(const std::string& opt, int weight) {
1205 return compute_weight(get_option_value_int(opt), weight);
1209 // init_safety() initizes the king safety evaluation, based on UCI
1210 // parameters. It is called from read_weights().
1212 void init_safety() {
1214 QueenContactCheckBonus = get_option_value_int("Queen Contact Check Bonus");
1215 QueenCheckBonus = get_option_value_int("Queen Check Bonus");
1216 RookCheckBonus = get_option_value_int("Rook Check Bonus");
1217 BishopCheckBonus = get_option_value_int("Bishop Check Bonus");
1218 KnightCheckBonus = get_option_value_int("Knight Check Bonus");
1219 DiscoveredCheckBonus = get_option_value_int("Discovered Check Bonus");
1220 MateThreatBonus = get_option_value_int("Mate Threat Bonus");
1222 int maxSlope = get_option_value_int("King Safety Max Slope");
1223 int peak = get_option_value_int("King Safety Max Value") * 256 / 100;
1224 double a = get_option_value_int("King Safety Coefficient") / 100.0;
1225 double b = get_option_value_int("King Safety X Intercept");
1226 bool quad = (get_option_value_string("King Safety Curve") == "Quadratic");
1227 bool linear = (get_option_value_string("King Safety Curve") == "Linear");
1229 for (int i = 0; i < 100; i++)
1232 SafetyTable[i] = Value(0);
1234 SafetyTable[i] = Value((int)(a * (i - b) * (i - b)));
1236 SafetyTable[i] = Value((int)(100 * a * (i - b)));
1239 for (int i = 0; i < 100; i++)
1241 if (SafetyTable[i+1] - SafetyTable[i] > maxSlope)
1242 for (int j = i + 1; j < 100; j++)
1243 SafetyTable[j] = SafetyTable[j-1] + Value(maxSlope);
1245 if (SafetyTable[i] > Value(peak))
1246 SafetyTable[i] = Value(peak);