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 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/>.
33 #include "ucioption.h"
37 //// Local definitions
42 const int Sign[2] = {1, -1};
44 // Evaluation grain size, must be a power of 2.
45 const int GrainSize = 4;
48 int WeightMobilityMidgame = 0x100;
49 int WeightMobilityEndgame = 0x100;
50 int WeightPawnStructureMidgame = 0x100;
51 int WeightPawnStructureEndgame = 0x100;
52 int WeightPassedPawnsMidgame = 0x100;
53 int WeightPassedPawnsEndgame = 0x100;
54 int WeightKingSafety[2] = { 0x100, 0x100 };
57 // Internal evaluation weights. These are applied on top of the evaluation
58 // weights read from UCI parameters. The purpose is to be able to change
59 // the evaluation weights while keeping the default values of the UCI
60 // parameters at 100, which looks prettier.
61 const int WeightMobilityMidgameInternal = 0x100;
62 const int WeightMobilityEndgameInternal = 0x100;
63 const int WeightPawnStructureMidgameInternal = 0x100;
64 const int WeightPawnStructureEndgameInternal = 0x100;
65 const int WeightPassedPawnsMidgameInternal = 0x100;
66 const int WeightPassedPawnsEndgameInternal = 0x100;
67 const int WeightKingSafetyInternal = 0x110;
68 const int WeightKingOppSafetyInternal = 0x110;
69 const int WeightSpaceInternal = 0x30;
71 // Visually better to define tables constants
74 // Knight mobility bonus in middle game and endgame, indexed by the number
75 // of attacked squares not occupied by friendly piecess.
76 const Value MidgameKnightMobilityBonus[] = {
78 V(-30), V(-20),V(-10), V(0), V(10), V(20), V(25), V(30), V(30)
81 const Value EndgameKnightMobilityBonus[] = {
83 V(-30), V(-20),V(-10), V(0), V(10), V(20), V(25), V(30), V(30)
86 // Bishop mobility bonus in middle game and endgame, indexed by the number
87 // of attacked squares not occupied by friendly pieces. X-ray attacks through
88 // queens are also included.
89 const Value MidgameBishopMobilityBonus[] = {
91 V(-30), V(-15), V(0), V(15), V(30), V(45), V(58), V(66),
92 // 8 9 10 11 12 13 14 15
93 V( 72), V( 76), V(78), V(80), V(81), V(82), V(83), V(83)
96 const Value EndgameBishopMobilityBonus[] = {
98 V(-30), V(-15), V(0), V(15), V(30), V(45), V(58), V(66),
99 // 8 9 10 11 12 13 14 15
100 V( 72), V( 76), V(78), V(80), V(81), V(82), V(83), V(83)
103 // Rook mobility bonus in middle game and endgame, indexed by the number
104 // of attacked squares not occupied by friendly pieces. X-ray attacks through
105 // queens and rooks are also included.
106 const Value MidgameRookMobilityBonus[] = {
108 V(-18), V(-12), V(-6), V(0), V(6), V(12), V(16), V(21),
109 // 8 9 10 11 12 13 14 15
110 V( 24), V( 27), V(28), V(29), V(30), V(31), V(32), V(33)
113 const Value EndgameRookMobilityBonus[] = {
115 V(-30), V(-18), V(-6), V(6), V(18), V(30), V(42), V(54),
116 // 8 9 10 11 12 13 14 15
117 V( 66), V( 74), V(78), V(80), V(81), V(82), V(83), V(83)
120 // Queen mobility bonus in middle game and endgame, indexed by the number
121 // of attacked squares not occupied by friendly pieces.
122 const Value MidgameQueenMobilityBonus[] = {
124 V(-10), V(-8), V(-6), V(-4), V(-2), V( 0), V( 2), V( 4),
125 // 8 9 10 11 12 13 14 15
126 V( 6), V( 8), V(10), V(12), V(13), V(14), V(15), V(16),
127 // 16 17 18 19 20 21 22 23
128 V( 16), V(16), V(16), V(16), V(16), V(16), V(16), V(16),
129 // 24 25 26 27 28 29 30 31
130 V( 16), V(16), V(16), V(16), V(16), V(16), V(16), V(16)
133 const Value EndgameQueenMobilityBonus[] = {
135 V(-20),V(-15),V(-10), V(-5), V( 0), V( 5), V(10), V(15),
136 // 8 9 10 11 12 13 14 15
137 V( 19), V(23), V(27), V(29), V(30), V(30), V(30), V(30),
138 // 16 17 18 19 20 21 22 23
139 V( 30), V(30), V(30), V(30), V(30), V(30), V(30), V(30),
140 // 24 25 26 27 28 29 30 31
141 V( 30), V(30), V(30), V(30), V(30), V(30), V(30), V(30)
144 // Outpost bonuses for knights and bishops, indexed by square (from white's
146 const Value KnightOutpostBonus[64] = {
148 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 1
149 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 2
150 V(0), V(0), V(5),V(10),V(10), V(5), V(0), V(0), // 3
151 V(0), V(5),V(20),V(30),V(30),V(20), V(5), V(0), // 4
152 V(0),V(10),V(30),V(40),V(40),V(30),V(10), V(0), // 5
153 V(0), V(5),V(20),V(20),V(20),V(20), V(5), V(0), // 6
154 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 7
155 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8
158 const Value BishopOutpostBonus[64] = {
160 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 1
161 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 2
162 V(0), V(0), V(5), V(5), V(5), V(5), V(0), V(0), // 3
163 V(0), V(5),V(10),V(10),V(10),V(10), V(5), V(0), // 4
164 V(0),V(10),V(20),V(20),V(20),V(20),V(10), V(0), // 5
165 V(0), V(5), V(8), V(8), V(8), V(8), V(5), V(0), // 6
166 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0), // 7
167 V(0), V(0), V(0), V(0), V(0), V(0), V(0), V(0) // 8
170 // Bonus for unstoppable passed pawns:
171 const Value UnstoppablePawnValue = Value(0x500);
173 // Rooks and queens on the 7th rank:
174 const Value MidgameRookOn7thBonus = Value(50);
175 const Value EndgameRookOn7thBonus = Value(100);
176 const Value MidgameQueenOn7thBonus = Value(25);
177 const Value EndgameQueenOn7thBonus = Value(50);
179 // Rooks on open files:
180 const Value RookOpenFileBonus = Value(40);
181 const Value RookHalfOpenFileBonus = Value(20);
183 // Penalty for rooks trapped inside a friendly king which has lost the
185 const Value TrappedRookPenalty = Value(180);
187 // Penalty for a bishop on a7/h7 (a2/h2 for black) which is trapped by
189 const Value TrappedBishopA7H7Penalty = Value(300);
191 // Bitboard masks for detecting trapped bishops on a7/h7 (a2/h2 for black):
192 const Bitboard MaskA7H7[2] = {
193 ((1ULL << SQ_A7) | (1ULL << SQ_H7)),
194 ((1ULL << SQ_A2) | (1ULL << SQ_H2))
197 // Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
198 // a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
199 // happen in Chess960 games.
200 const Value TrappedBishopA1H1Penalty = Value(100);
202 // Bitboard masks for detecting trapped bishops on a1/h1 (a8/h8 for black):
203 const Bitboard MaskA1H1[2] = {
204 ((1ULL << SQ_A1) | (1ULL << SQ_H1)),
205 ((1ULL << SQ_A8) | (1ULL << SQ_H8))
208 // The SpaceMask[color] contains area of the board which is consdered by
209 // the space evaluation. In the middle game, each side is given a bonus
210 // based on how many squares inside this area are safe and available for
211 // friendly minor pieces.
212 const Bitboard SpaceMask[2] = {
213 (1ULL<<SQ_C2) | (1ULL<<SQ_D2) | (1ULL<<SQ_E2) | (1ULL<<SQ_F2) |
214 (1ULL<<SQ_C3) | (1ULL<<SQ_D3) | (1ULL<<SQ_E3) | (1ULL<<SQ_F3) |
215 (1ULL<<SQ_C4) | (1ULL<<SQ_D4) | (1ULL<<SQ_E4) | (1ULL<<SQ_F4),
216 (1ULL<<SQ_C7) | (1ULL<<SQ_D7) | (1ULL<<SQ_E7) | (1ULL<<SQ_F7) |
217 (1ULL<<SQ_C6) | (1ULL<<SQ_D6) | (1ULL<<SQ_E6) | (1ULL<<SQ_F6) |
218 (1ULL<<SQ_C5) | (1ULL<<SQ_D5) | (1ULL<<SQ_E5) | (1ULL<<SQ_F5)
221 /// King safety constants and variables. The king safety scores are taken
222 /// from the array SafetyTable[]. Various little "meta-bonuses" measuring
223 /// the strength of the attack are added up into an integer, which is used
224 /// as an index to SafetyTable[].
226 // Attack weights for each piece type.
227 const int QueenAttackWeight = 5;
228 const int RookAttackWeight = 3;
229 const int BishopAttackWeight = 2;
230 const int KnightAttackWeight = 2;
232 // Bonuses for safe checks for each piece type.
233 int QueenContactCheckBonus = 3;
234 int QueenCheckBonus = 2;
235 int RookCheckBonus = 1;
236 int BishopCheckBonus = 1;
237 int KnightCheckBonus = 1;
238 int DiscoveredCheckBonus = 3;
240 // Scan for queen contact mates?
241 const bool QueenContactMates = true;
243 // Bonus for having a mate threat.
244 int MateThreatBonus = 3;
246 // InitKingDanger[] contains bonuses based on the position of the defending
248 const int InitKingDanger[64] = {
249 2, 0, 2, 5, 5, 2, 0, 2,
250 2, 2, 4, 8, 8, 4, 2, 2,
251 7, 10, 12, 12, 12, 12, 10, 7,
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,
255 15, 15, 15, 15, 15, 15, 15, 15,
256 15, 15, 15, 15, 15, 15, 15, 15
259 // SafetyTable[] contains the actual king safety scores. It is initialized
261 Value SafetyTable[100];
263 // Pawn and material hash tables, indexed by the current thread id
264 PawnInfoTable *PawnTable[8] = {0, 0, 0, 0, 0, 0, 0, 0};
265 MaterialInfoTable *MaterialTable[8] = {0, 0, 0, 0, 0, 0, 0, 0};
267 // Sizes of pawn and material hash tables
268 const int PawnTableSize = 16384;
269 const int MaterialTableSize = 1024;
271 // Array which gives the number of nonzero bits in an 8-bit integer:
272 uint8_t BitCount8Bit[256];
274 // Function prototypes
275 void evaluate_knight(const Position& p, Square s, Color us, Bitboard pinned, EvalInfo& ei);
276 void evaluate_bishop(const Position& p, Square s, Color us, Bitboard pinned, EvalInfo& ei);
277 void evaluate_rook(const Position& p, Square s, Color us, Bitboard pinned, EvalInfo& ei);
278 void evaluate_queen(const Position& p, Square s, Color us, Bitboard pinned, EvalInfo& ei);
279 void evaluate_king(const Position& p, Square s, Color us, EvalInfo& ei);
281 void evaluate_passed_pawns(const Position &pos, EvalInfo &ei);
282 void evaluate_trapped_bishop_a7h7(const Position &pos, Square s, Color us,
284 void evaluate_trapped_bishop_a1h1(const Position &pos, Square s, Color us,
287 void evaluate_space(const Position &p, Color us, EvalInfo &ei);
288 inline Value apply_weight(Value v, int w);
289 Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]);
291 int count_1s_8bit(Bitboard b);
293 int compute_weight(int uciWeight, int internalWeight);
294 int weight_option(const std::string& opt, int weight);
304 /// evaluate() is the main evaluation function. It always computes two
305 /// values, an endgame score and a middle game score, and interpolates
306 /// between them based on the remaining material.
308 Value 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->mg_value();
323 ei.egValue += ei.mi->eg_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.piece_attacks<KING>(pos.king_square(WHITE));
342 ei.attackedBy[BLACK][KING] = pos.piece_attacks<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] = ((pos.pawns(WHITE) << 9) & ~FileABB) | ((pos.pawns(WHITE) << 7) & ~FileHBB);
348 ei.attackedBy[BLACK][PAWN] = ((pos.pawns(BLACK) >> 7) & ~FileABB) | ((pos.pawns(BLACK) >> 9) & ~FileHBB);
349 ei.kingAttackersCount[WHITE] = count_1s_max_15(ei.attackedBy[WHITE][PAWN] & ei.attackedBy[BLACK][KING])/2;
350 ei.kingAttackersCount[BLACK] = count_1s_max_15(ei.attackedBy[BLACK][PAWN] & ei.attackedBy[WHITE][KING])/2;
353 for (Color c = WHITE; c <= BLACK; c++)
355 Bitboard pinned = pos.pinned_pieces(c);
358 for (int i = 0; i < pos.piece_count(c, KNIGHT); i++)
359 evaluate_knight(pos, pos.piece_list(c, KNIGHT, i), c, pinned, ei);
362 for (int i = 0; i < pos.piece_count(c, BISHOP); i++)
363 evaluate_bishop(pos, pos.piece_list(c, BISHOP, i), c, pinned, ei);
366 for (int i = 0; i < pos.piece_count(c, ROOK); i++)
367 evaluate_rook(pos, pos.piece_list(c, ROOK, i), c, pinned, ei);
370 for(int i = 0; i < pos.piece_count(c, QUEEN); i++)
371 evaluate_queen(pos, pos.piece_list(c, QUEEN, i), c, pinned, ei);
373 // Special pattern: trapped bishops on a7/h7/a2/h2
374 Bitboard b = pos.bishops(c) & MaskA7H7[c];
377 Square s = pop_1st_bit(&b);
378 evaluate_trapped_bishop_a7h7(pos, s, c, ei);
381 // Special pattern: trapped bishops on a1/h1/a8/h8 in Chess960:
384 b = pos.bishops(c) & MaskA1H1[c];
387 Square s = pop_1st_bit(&b);
388 evaluate_trapped_bishop_a1h1(pos, s, c, ei);
392 // Sum up all attacked squares
393 ei.attackedBy[c][0] = ei.attackedBy[c][PAWN] | ei.attackedBy[c][KNIGHT]
394 | ei.attackedBy[c][BISHOP] | ei.attackedBy[c][ROOK]
395 | ei.attackedBy[c][QUEEN] | ei.attackedBy[c][KING];
398 // Kings. Kings are evaluated after all other pieces for both sides,
399 // because we need complete attack information for all pieces when computing
400 // the king safety evaluation.
401 for (Color c = WHITE; c <= BLACK; c++)
402 evaluate_king(pos, pos.king_square(c), c, ei);
404 // Evaluate passed pawns. We evaluate passed pawns for both sides at once,
405 // because we need to know which side promotes first in positions where
406 // both sides have an unstoppable passed pawn.
407 if (ei.pi->passed_pawns())
408 evaluate_passed_pawns(pos, ei);
410 Phase phase = pos.game_phase();
412 // Middle-game specific evaluation terms
413 if (phase > PHASE_ENDGAME)
415 // Pawn storms in positions with opposite castling.
416 if ( square_file(pos.king_square(WHITE)) >= FILE_E
417 && square_file(pos.king_square(BLACK)) <= FILE_D)
419 ei.mgValue += ei.pi->queenside_storm_value(WHITE)
420 - ei.pi->kingside_storm_value(BLACK);
422 else if ( square_file(pos.king_square(WHITE)) <= FILE_D
423 && square_file(pos.king_square(BLACK)) >= FILE_E)
425 ei.mgValue += ei.pi->kingside_storm_value(WHITE)
426 - ei.pi->queenside_storm_value(BLACK);
428 // Evaluate space for both sides
429 if (ei.mi->space_weight() > 0)
431 evaluate_space(pos, WHITE, ei);
432 evaluate_space(pos, BLACK, ei);
437 ei.mgValue += apply_weight(ei.mgMobility, WeightMobilityMidgame);
438 ei.egValue += apply_weight(ei.egMobility, WeightMobilityEndgame);
440 // If we don't already have an unusual scale factor, check for opposite
441 // colored bishop endgames, and use a lower scale for those
442 if ( phase < PHASE_MIDGAME
443 && pos.opposite_colored_bishops()
444 && ( (factor[WHITE] == SCALE_FACTOR_NORMAL && ei.egValue > Value(0))
445 || (factor[BLACK] == SCALE_FACTOR_NORMAL && ei.egValue < Value(0))))
449 // Only the two bishops ?
450 if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
451 && pos.non_pawn_material(BLACK) == BishopValueMidgame)
453 // Check for KBP vs KB with only a single pawn that is almost
454 // certainly a draw or at least two pawns.
455 bool one_pawn = (pos.piece_count(WHITE, PAWN) + pos.piece_count(BLACK, PAWN) == 1);
456 sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
459 // Endgame with opposite-colored bishops, but also other pieces. Still
460 // a bit drawish, but not as drawish as with only the two bishops.
461 sf = ScaleFactor(50);
463 if (factor[WHITE] == SCALE_FACTOR_NORMAL)
465 if (factor[BLACK] == SCALE_FACTOR_NORMAL)
469 // Interpolate between the middle game and the endgame score, and
471 Color stm = pos.side_to_move();
473 Value v = Sign[stm] * scale_by_game_phase(ei.mgValue, ei.egValue, phase, factor);
475 return (ei.mateThreat[stm] == MOVE_NONE ? v : 8 * QueenValueMidgame - v);
479 /// quick_evaluate() does a very approximate evaluation of the current position.
480 /// It currently considers only material and piece square table scores. Perhaps
481 /// we should add scores from the pawn and material hash tables?
483 Value quick_evaluate(const Position &pos) {
488 ScaleFactor sf[2] = {SCALE_FACTOR_NORMAL, SCALE_FACTOR_NORMAL};
490 Value mgv = pos.mg_value();
491 Value egv = pos.eg_value();
492 Phase ph = pos.game_phase();
493 Color stm = pos.side_to_move();
495 return Sign[stm] * scale_by_game_phase(mgv, egv, ph, sf);
499 /// init_eval() initializes various tables used by the evaluation function.
501 void init_eval(int threads) {
503 assert(threads <= THREAD_MAX);
505 for (int i = 0; i < THREAD_MAX; i++)
510 delete MaterialTable[i];
512 MaterialTable[i] = NULL;
516 PawnTable[i] = new PawnInfoTable(PawnTableSize);
517 if (!MaterialTable[i])
518 MaterialTable[i] = new MaterialInfoTable(MaterialTableSize);
521 for (Bitboard b = 0ULL; b < 256ULL; b++)
522 BitCount8Bit[b] = count_1s(b);
526 /// quit_eval() releases heap-allocated memory at program termination.
530 for (int i = 0; i < THREAD_MAX; i++)
533 delete MaterialTable[i];
538 /// read_weights() reads evaluation weights from the corresponding UCI
541 void read_weights(Color us) {
543 WeightMobilityMidgame = weight_option("Mobility (Middle Game)", WeightMobilityMidgameInternal);
544 WeightMobilityEndgame = weight_option("Mobility (Endgame)", WeightMobilityEndgameInternal);
545 WeightPawnStructureMidgame = weight_option("Pawn Structure (Middle Game)", WeightPawnStructureMidgameInternal);
546 WeightPawnStructureEndgame = weight_option("Pawn Structure (Endgame)", WeightPawnStructureEndgameInternal);
547 WeightPassedPawnsMidgame = weight_option("Passed Pawns (Middle Game)", WeightPassedPawnsMidgameInternal);
548 WeightPassedPawnsEndgame = weight_option("Passed Pawns (Endgame)", WeightPassedPawnsEndgameInternal);
550 Color them = opposite_color(us);
552 WeightKingSafety[us] = weight_option("Cowardice", WeightKingSafetyInternal);
553 WeightKingSafety[them] = weight_option("Aggressiveness", WeightKingOppSafetyInternal);
554 WeightSpace = weight_option("Space", WeightSpaceInternal);
562 // evaluate_common() computes terms common to all pieces attack
564 template<PieceType Piece>
565 int evaluate_common(const Position& p, const Bitboard& b, Color us, Bitboard pinned, EvalInfo& ei, Square s = SQ_NONE) {
567 static const int AttackWeight[] = { 0, 0, KnightAttackWeight, BishopAttackWeight, RookAttackWeight, QueenAttackWeight };
568 static const Value* MgBonus[] = { 0, 0, MidgameKnightMobilityBonus, MidgameBishopMobilityBonus, MidgameRookMobilityBonus, MidgameQueenMobilityBonus };
569 static const Value* EgBonus[] = { 0, 0, EndgameKnightMobilityBonus, EndgameBishopMobilityBonus, EndgameRookMobilityBonus, EndgameQueenMobilityBonus };
570 static const Value* OutpostBonus[] = { 0, 0, KnightOutpostBonus, BishopOutpostBonus, 0, 0 };
573 Color them = opposite_color(us);
575 // Update attack info
576 ei.attackedBy[us][Piece] |= b;
579 if (b & ei.kingZone[us])
581 ei.kingAttackersCount[us]++;
582 ei.kingAttackersWeight[us] += AttackWeight[Piece];
583 Bitboard bb = (b & ei.attackedBy[them][KING]);
585 ei.kingAdjacentZoneAttacksCount[us] += count_1s_max_15(bb);
588 if (pinned && bit_is_set(pinned, s))
592 // Remove squares protected by enemy pawns
593 Bitboard bb = (b & ~ei.attackedBy[them][PAWN]);
596 mob = (Piece != QUEEN ? count_1s_max_15(bb & ~p.pieces_of_color(us))
597 : count_1s(bb & ~p.pieces_of_color(us)));
599 ei.mgMobility += Sign[us] * MgBonus[Piece][mob];
600 ei.egMobility += Sign[us] * EgBonus[Piece][mob];
603 // Bishop and Knight outposts
604 if ( (Piece != BISHOP && Piece != KNIGHT) // compile time condition
605 || !p.square_is_weak(s, them))
608 // Initial bonus based on square
610 v = bonus = OutpostBonus[Piece][relative_square(us, s)];
612 // Increase bonus if supported by pawn, especially if the opponent has
613 // no minor piece which can exchange the outpost piece
614 if (v && (p.pawn_attacks(them, s) & p.pawns(us)))
617 if ( p.piece_count(them, KNIGHT) == 0
618 && (SquaresByColorBB[square_color(s)] & p.bishops(them)) == EmptyBoardBB)
621 ei.mgValue += Sign[us] * bonus;
622 ei.egValue += Sign[us] * bonus;
627 // evaluate_knight() assigns bonuses and penalties to a knight of a given
628 // color on a given square.
630 void evaluate_knight(const Position& p, Square s, Color us, Bitboard pinned, EvalInfo& ei) {
632 // Attacks, mobility and outposts
633 evaluate_common<KNIGHT>(p, p.piece_attacks<KNIGHT>(s), us, pinned, ei, s);
637 // evaluate_bishop() assigns bonuses and penalties to a bishop of a given
638 // color on a given square.
640 void evaluate_bishop(const Position& p, Square s, Color us, Bitboard pinned, EvalInfo& ei) {
642 Bitboard b = bishop_attacks_bb(s, p.occupied_squares() & ~p.queens(us));
644 // Attacks, mobility and outposts
645 evaluate_common<BISHOP>(p, b, us, pinned, ei, s);
649 // evaluate_rook() assigns bonuses and penalties to a rook of a given
650 // color on a given square.
652 void evaluate_rook(const Position& p, Square s, Color us, Bitboard pinned, EvalInfo& ei) {
654 Bitboard b = rook_attacks_bb(s, p.occupied_squares() & ~p.rooks_and_queens(us));
656 // Attacks and mobility
657 int mob = evaluate_common<ROOK>(p, b, us, pinned, ei);
660 Color them = opposite_color(us);
662 if ( relative_rank(us, s) == RANK_7
663 && relative_rank(us, p.king_square(them)) == RANK_8)
665 ei.mgValue += Sign[us] * MidgameRookOn7thBonus;
666 ei.egValue += Sign[us] * EndgameRookOn7thBonus;
669 // Open and half-open files
670 File f = square_file(s);
671 if (ei.pi->file_is_half_open(us, f))
673 if (ei.pi->file_is_half_open(them, f))
675 ei.mgValue += Sign[us] * RookOpenFileBonus;
676 ei.egValue += Sign[us] * RookOpenFileBonus;
680 ei.mgValue += Sign[us] * RookHalfOpenFileBonus;
681 ei.egValue += Sign[us] * RookHalfOpenFileBonus;
685 // Penalize rooks which are trapped inside a king. Penalize more if
686 // king has lost right to castle
687 if (mob > 6 || ei.pi->file_is_half_open(us, f))
690 Square ksq = p.king_square(us);
692 if ( square_file(ksq) >= FILE_E
693 && square_file(s) > square_file(ksq)
694 && (relative_rank(us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
696 // Is there a half-open file between the king and the edge of the board?
697 if (!ei.pi->has_open_file_to_right(us, square_file(ksq)))
698 ei.mgValue -= p.can_castle(us)? Sign[us] * ((TrappedRookPenalty - mob * 16) / 2)
699 : Sign[us] * (TrappedRookPenalty - mob * 16);
701 else if ( square_file(ksq) <= FILE_D
702 && square_file(s) < square_file(ksq)
703 && (relative_rank(us, ksq) == RANK_1 || square_rank(ksq) == square_rank(s)))
705 // Is there a half-open file between the king and the edge of the board?
706 if (!ei.pi->has_open_file_to_left(us, square_file(ksq)))
707 ei.mgValue -= p.can_castle(us)? Sign[us] * ((TrappedRookPenalty - mob * 16) / 2)
708 : Sign[us] * (TrappedRookPenalty - mob * 16);
713 // evaluate_queen() assigns bonuses and penalties to a queen of a given
714 // color on a given square.
716 void evaluate_queen(const Position& p, Square s, Color us, Bitboard pinned, EvalInfo& ei) {
718 // Attacks and mobility
719 evaluate_common<QUEEN>(p, p.piece_attacks<QUEEN>(s), us, pinned, ei);
722 Color them = opposite_color(us);
724 if ( relative_rank(us, s) == RANK_7
725 && relative_rank(us, p.king_square(them)) == RANK_8)
727 ei.mgValue += Sign[us] * MidgameQueenOn7thBonus;
728 ei.egValue += Sign[us] * EndgameQueenOn7thBonus;
732 inline Bitboard shiftRowsDown(const Bitboard& b, int num) {
734 return b >> (num << 3);
737 // evaluate_king() assigns bonuses and penalties to a king of a given
738 // color on a given square.
740 void evaluate_king(const Position& p, Square s, Color us, EvalInfo& ei) {
742 int shelter = 0, sign = Sign[us];
745 if (relative_rank(us, s) <= RANK_4)
747 Bitboard pawns = p.pawns(us) & this_and_neighboring_files_bb(s);
748 Rank r = square_rank(s);
749 for (int i = 1; i < 4; i++)
750 shelter += count_1s_8bit(shiftRowsDown(pawns, r+i*sign)) * (128>>i);
752 ei.mgValue += sign * Value(shelter);
755 // King safety. This is quite complicated, and is almost certainly far
756 // from optimally tuned.
757 Color them = opposite_color(us);
759 if ( p.piece_count(them, QUEEN) >= 1
760 && ei.kingAttackersCount[them] >= 2
761 && p.non_pawn_material(them) >= QueenValueMidgame + RookValueMidgame
762 && ei.kingAdjacentZoneAttacksCount[them])
764 // Is it the attackers turn to move?
765 bool sente = (them == p.side_to_move());
767 // Find the attacked squares around the king which has no defenders
768 // apart from the king itself
769 Bitboard undefended =
770 ei.attacked_by(them) & ~ei.attacked_by(us, PAWN)
771 & ~ei.attacked_by(us, KNIGHT) & ~ei.attacked_by(us, BISHOP)
772 & ~ei.attacked_by(us, ROOK) & ~ei.attacked_by(us, QUEEN)
773 & ei.attacked_by(us, KING);
775 Bitboard occ = p.occupied_squares(), b, b2;
777 // Initialize the 'attackUnits' variable, which is used later on as an
778 // index to the SafetyTable[] array. The initial value is based on the
779 // number and types of the attacking pieces, the number of attacked and
780 // undefended squares around the king, the square of the king, and the
781 // quality of the pawn shelter.
783 Min((ei.kingAttackersCount[them] * ei.kingAttackersWeight[them]) / 2, 25)
784 + (ei.kingAdjacentZoneAttacksCount[them] + count_1s_max_15(undefended)) * 3
785 + InitKingDanger[relative_square(us, s)] - (shelter >> 5);
787 // Analyse safe queen contact checks
788 b = undefended & ei.attacked_by(them, QUEEN) & ~p.pieces_of_color(them);
791 Bitboard attackedByOthers =
792 ei.attacked_by(them, PAWN) | ei.attacked_by(them, KNIGHT)
793 | ei.attacked_by(them, BISHOP) | ei.attacked_by(them, ROOK);
795 b &= attackedByOthers;
798 // The bitboard b now contains the squares available for safe queen
800 int count = count_1s_max_15(b);
801 attackUnits += QueenContactCheckBonus * count * (sente ? 2 : 1);
803 // Is there a mate threat?
804 if (QueenContactMates && !p.is_check())
806 Bitboard escapeSquares =
807 p.piece_attacks<KING>(s) & ~p.pieces_of_color(us) & ~attackedByOthers;
811 Square from, to = pop_1st_bit(&b);
812 if (!(escapeSquares & ~queen_attacks_bb(to, occ & ClearMaskBB[s])))
814 // We have a mate, unless the queen is pinned or there
815 // is an X-ray attack through the queen.
816 for (int i = 0; i < p.piece_count(them, QUEEN); i++)
818 from = p.piece_list(them, QUEEN, i);
819 if ( bit_is_set(p.piece_attacks<QUEEN>(from), to)
820 && !bit_is_set(p.pinned_pieces(them), from)
821 && !(rook_attacks_bb(to, occ & ClearMaskBB[from]) & p.rooks_and_queens(us))
822 && !(rook_attacks_bb(to, occ & ClearMaskBB[from]) & p.rooks_and_queens(us)))
824 ei.mateThreat[them] = make_move(from, to);
832 // Analyse safe distance checks
833 if (QueenCheckBonus > 0 || RookCheckBonus > 0)
835 b = p.piece_attacks<ROOK>(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
838 b2 = b & ei.attacked_by(them, QUEEN);
840 attackUnits += QueenCheckBonus * count_1s_max_15(b2);
843 b2 = b & ei.attacked_by(them, ROOK);
845 attackUnits += RookCheckBonus * count_1s_max_15(b2);
847 if (QueenCheckBonus > 0 || BishopCheckBonus > 0)
849 b = p.piece_attacks<BISHOP>(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
852 b2 = b & ei.attacked_by(them, QUEEN);
854 attackUnits += QueenCheckBonus * count_1s_max_15(b2);
857 b2 = b & ei.attacked_by(them, BISHOP);
859 attackUnits += BishopCheckBonus * count_1s_max_15(b2);
861 if (KnightCheckBonus > 0)
863 b = p.piece_attacks<KNIGHT>(s) & ~p.pieces_of_color(them) & ~ei.attacked_by(us);
866 b2 = b & ei.attacked_by(them, KNIGHT);
868 attackUnits += KnightCheckBonus * count_1s_max_15(b2);
871 // Analyse discovered checks (only for non-pawns right now, consider
872 // adding pawns later).
873 if (DiscoveredCheckBonus)
875 b = p.discovered_check_candidates(them) & ~p.pawns();
877 attackUnits += DiscoveredCheckBonus * count_1s_max_15(b) * (sente? 2 : 1);
880 // Has a mate threat been found? We don't do anything here if the
881 // side with the mating move is the side to move, because in that
882 // case the mating side will get a huge bonus at the end of the main
883 // evaluation function instead.
884 if (ei.mateThreat[them] != MOVE_NONE)
885 attackUnits += MateThreatBonus;
887 // Ensure that attackUnits is between 0 and 99, in order to avoid array
888 // out of bounds errors:
892 if (attackUnits >= 100)
895 // Finally, extract the king safety score from the SafetyTable[] array.
896 // Add the score to the evaluation, and also to ei.futilityMargin. The
897 // reason for adding the king safety score to the futility margin is
898 // that the king safety scores can sometimes be very big, and that
899 // capturing a single attacking piece can therefore result in a score
900 // change far bigger than the value of the captured piece.
901 Value v = apply_weight(SafetyTable[attackUnits], WeightKingSafety[us]);
903 ei.mgValue -= sign * v;
905 if (us == p.side_to_move())
906 ei.futilityMargin += v;
911 // evaluate_passed_pawns() evaluates the passed pawns for both sides.
913 void evaluate_passed_pawns(const Position &pos, EvalInfo &ei) {
915 bool hasUnstoppable[2] = {false, false};
916 int movesToGo[2] = {100, 100};
918 for (Color us = WHITE; us <= BLACK; us++)
920 Color them = opposite_color(us);
921 Square ourKingSq = pos.king_square(us);
922 Square theirKingSq = pos.king_square(them);
923 Bitboard b = ei.pi->passed_pawns() & pos.pawns(us), b2, b3, b4;
927 Square s = pop_1st_bit(&b);
929 assert(pos.piece_on(s) == piece_of_color_and_type(us, PAWN));
930 assert(pos.pawn_is_passed(us, s));
932 int r = int(relative_rank(us, s) - RANK_2);
933 int tr = Max(0, r * (r - 1));
934 Square blockSq = s + pawn_push(us);
936 // Base bonus based on rank
937 Value mbonus = Value(20 * tr);
938 Value ebonus = Value(10 + r * r * 10);
940 // Adjust bonus based on king proximity
943 ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr);
944 ebonus -= Value(square_distance(ourKingSq, blockSq + pawn_push(us)) * 1 * tr);
945 ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr);
947 // If the pawn is free to advance, increase bonus
948 if (pos.square_is_empty(blockSq))
950 b2 = squares_in_front_of(us, s);
951 b3 = b2 & ei.attacked_by(them);
952 b4 = b2 & ei.attacked_by(us);
954 // If there is an enemy rook or queen attacking the pawn from behind,
955 // add all X-ray attacks by the rook or queen.
956 if ( bit_is_set(ei.attacked_by(them,ROOK) | ei.attacked_by(them,QUEEN),s)
957 && (squares_behind(us, s) & pos.rooks_and_queens(them)))
960 if ((b2 & pos.pieces_of_color(them)) == EmptyBoardBB)
962 // There are no enemy pieces in the pawn's path! Are any of the
963 // squares in the pawn's path attacked by the enemy?
964 if (b3 == EmptyBoardBB)
965 // No enemy attacks, huge bonus!
966 ebonus += Value(tr * (b2 == b4 ? 17 : 15));
968 // OK, there are enemy attacks. Are those squares which are
969 // attacked by the enemy also attacked by us? If yes, big bonus
970 // (but smaller than when there are no enemy attacks), if no,
971 // somewhat smaller bonus.
972 ebonus += Value(tr * ((b3 & b4) == b3 ? 13 : 8));
976 // There are some enemy pieces in the pawn's path. While this is
977 // sad, we still assign a moderate bonus if all squares in the path
978 // which are either occupied by or attacked by enemy pieces are
979 // also attacked by us.
980 if (((b3 | (b2 & pos.pieces_of_color(them))) & ~b4) == EmptyBoardBB)
981 ebonus += Value(tr * 6);
983 // At last, add a small bonus when there are no *friendly* pieces
984 // in the pawn's path.
985 if ((b2 & pos.pieces_of_color(us)) == EmptyBoardBB)
990 // If the pawn is supported by a friendly pawn, increase bonus
991 b2 = pos.pawns(us) & neighboring_files_bb(s);
993 ebonus += Value(r * 20);
994 else if (pos.pawn_attacks(them, s) & b2)
995 ebonus += Value(r * 12);
997 // If the other side has only a king, check whether the pawn is
999 if (pos.non_pawn_material(them) == Value(0))
1004 qsq = relative_square(us, make_square(square_file(s), RANK_8));
1005 d = square_distance(s, qsq)
1006 - square_distance(theirKingSq, qsq)
1007 + (us != pos.side_to_move());
1011 int mtg = RANK_8 - relative_rank(us, s);
1012 int blockerCount = count_1s_max_15(squares_in_front_of(us,s) & pos.occupied_squares());
1013 mtg += blockerCount;
1017 hasUnstoppable[us] = true;
1018 movesToGo[us] = Min(movesToGo[us], mtg);
1022 // Rook pawns are a special case: They are sometimes worse, and
1023 // sometimes better than other passed pawns. It is difficult to find
1024 // good rules for determining whether they are good or bad. For now,
1025 // we try the following: Increase the value for rook pawns if the
1026 // other side has no pieces apart from a knight, and decrease the
1027 // value if the other side has a rook or queen.
1028 if (square_file(s) == FILE_A || square_file(s) == FILE_H)
1030 if( pos.non_pawn_material(them) <= KnightValueMidgame
1031 && pos.piece_count(them, KNIGHT) <= 1)
1032 ebonus += ebonus / 4;
1033 else if(pos.rooks_and_queens(them))
1034 ebonus -= ebonus / 4;
1037 // Add the scores for this pawn to the middle game and endgame eval.
1038 ei.mgValue += apply_weight(Sign[us] * mbonus, WeightPassedPawnsMidgame);
1039 ei.egValue += apply_weight(Sign[us] * ebonus, WeightPassedPawnsEndgame);
1043 // Does either side have an unstoppable passed pawn?
1044 if (hasUnstoppable[WHITE] && !hasUnstoppable[BLACK])
1045 ei.egValue += UnstoppablePawnValue - Value(0x40 * movesToGo[WHITE]);
1046 else if (hasUnstoppable[BLACK] && !hasUnstoppable[WHITE])
1047 ei.egValue -= UnstoppablePawnValue - Value(0x40 * movesToGo[BLACK]);
1048 else if (hasUnstoppable[BLACK] && hasUnstoppable[WHITE])
1050 // Both sides have unstoppable pawns! Try to find out who queens
1051 // first. We begin by transforming 'movesToGo' to the number of
1052 // plies until the pawn queens for both sides.
1053 movesToGo[WHITE] *= 2;
1054 movesToGo[BLACK] *= 2;
1055 movesToGo[pos.side_to_move()]--;
1057 // If one side queens at least three plies before the other, that
1059 if (movesToGo[WHITE] <= movesToGo[BLACK] - 3)
1060 ei.egValue += UnstoppablePawnValue - Value(0x40 * (movesToGo[WHITE]/2));
1061 else if(movesToGo[BLACK] <= movesToGo[WHITE] - 3)
1062 ei.egValue -= UnstoppablePawnValue - Value(0x40 * (movesToGo[BLACK]/2));
1064 // We could also add some rules about the situation when one side
1065 // queens exactly one ply before the other: Does the first queen
1066 // check the opponent's king, or attack the opponent's queening square?
1067 // This is slightly tricky to get right, because it is possible that
1068 // the opponent's king has moved somewhere before the first pawn queens.
1073 // evaluate_trapped_bishop_a7h7() determines whether a bishop on a7/h7
1074 // (a2/h2 for black) is trapped by enemy pawns, and assigns a penalty
1077 void evaluate_trapped_bishop_a7h7(const Position &pos, Square s, Color us,
1079 assert(square_is_ok(s));
1080 assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
1082 Square b6 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B6 : SQ_G6);
1083 Square b8 = relative_square(us, (square_file(s) == FILE_A) ? SQ_B8 : SQ_G8);
1085 if ( pos.piece_on(b6) == piece_of_color_and_type(opposite_color(us), PAWN)
1086 && pos.see(s, b6) < 0
1087 && pos.see(s, b8) < 0)
1089 ei.mgValue -= Sign[us] * TrappedBishopA7H7Penalty;
1090 ei.egValue -= Sign[us] * TrappedBishopA7H7Penalty;
1095 // evaluate_trapped_bishop_a1h1() determines whether a bishop on a1/h1
1096 // (a8/h8 for black) is trapped by a friendly pawn on b2/g2 (b7/g7 for
1097 // black), and assigns a penalty if it is. This pattern can obviously
1098 // only occur in Chess960 games.
1100 void evaluate_trapped_bishop_a1h1(const Position &pos, Square s, Color us,
1102 Piece pawn = piece_of_color_and_type(us, PAWN);
1106 assert(square_is_ok(s));
1107 assert(pos.piece_on(s) == piece_of_color_and_type(us, BISHOP));
1109 if (square_file(s) == FILE_A)
1111 b2 = relative_square(us, SQ_B2);
1112 b3 = relative_square(us, SQ_B3);
1113 c3 = relative_square(us, SQ_C3);
1117 b2 = relative_square(us, SQ_G2);
1118 b3 = relative_square(us, SQ_G3);
1119 c3 = relative_square(us, SQ_F3);
1122 if (pos.piece_on(b2) == pawn)
1126 if (!pos.square_is_empty(b3))
1127 penalty = 2*TrappedBishopA1H1Penalty;
1128 else if (pos.piece_on(c3) == pawn)
1129 penalty = TrappedBishopA1H1Penalty;
1131 penalty = TrappedBishopA1H1Penalty / 2;
1133 ei.mgValue -= Sign[us] * penalty;
1134 ei.egValue -= Sign[us] * penalty;
1139 // evaluate_space() computes the space evaluation for a given side. The
1140 // space evaluation is a simple bonus based on the number of safe squares
1141 // available for minor pieces on the central four files on ranks 2--4. Safe
1142 // squares one, two or three squares behind a friendly pawn are counted
1143 // twice. Finally, the space bonus is scaled by a weight taken from the
1144 // material hash table.
1146 void evaluate_space(const Position &pos, Color us, EvalInfo &ei) {
1148 Color them = opposite_color(us);
1150 // Find the safe squares for our pieces inside the area defined by
1151 // SpaceMask[us]. A square is unsafe it is attacked by an enemy
1152 // pawn, or if it is undefended and attacked by an enemy piece.
1154 Bitboard safeSquares = SpaceMask[us]
1156 & ~ei.attacked_by(them, PAWN)
1157 & ~(~ei.attacked_by(us) & ei.attacked_by(them));
1159 // Find all squares which are at most three squares behind some friendly
1161 Bitboard behindFriendlyPawns = pos.pawns(us);
1164 behindFriendlyPawns |= (behindFriendlyPawns >> 8);
1165 behindFriendlyPawns |= (behindFriendlyPawns >> 16);
1169 behindFriendlyPawns |= (behindFriendlyPawns << 8);
1170 behindFriendlyPawns |= (behindFriendlyPawns << 16);
1173 int space = count_1s_max_15(safeSquares)
1174 + count_1s_max_15(behindFriendlyPawns & safeSquares);
1176 ei.mgValue += Sign[us] * apply_weight(Value(space * ei.mi->space_weight()), WeightSpace);
1180 // apply_weight() applies an evaluation weight to a value
1182 inline Value apply_weight(Value v, int w) {
1183 return (v*w) / 0x100;
1187 // scale_by_game_phase() interpolates between a middle game and an endgame
1188 // score, based on game phase. It also scales the return value by a
1189 // ScaleFactor array.
1191 Value scale_by_game_phase(Value mv, Value ev, Phase ph, const ScaleFactor sf[]) {
1193 assert(mv > -VALUE_INFINITE && mv < VALUE_INFINITE);
1194 assert(ev > -VALUE_INFINITE && ev < VALUE_INFINITE);
1195 assert(ph >= PHASE_ENDGAME && ph <= PHASE_MIDGAME);
1197 ev = apply_scale_factor(ev, sf[(ev > Value(0) ? WHITE : BLACK)]);
1199 Value result = Value(int((mv * ph + ev * (128 - ph)) / 128));
1200 return Value(int(result) & ~(GrainSize - 1));
1204 // count_1s_8bit() counts the number of nonzero bits in the 8 least
1205 // significant bits of a Bitboard. This function is used by the king
1206 // shield evaluation.
1208 int count_1s_8bit(Bitboard b) {
1209 return int(BitCount8Bit[b & 0xFF]);
1213 // compute_weight() computes the value of an evaluation weight, by combining
1214 // an UCI-configurable weight with an internal weight.
1216 int compute_weight(int uciWeight, int internalWeight) {
1218 uciWeight = (uciWeight * 0x100) / 100;
1219 return (uciWeight * internalWeight) / 0x100;
1223 // helper used in read_weights()
1224 int weight_option(const std::string& opt, int weight) {
1226 return compute_weight(get_option_value_int(opt), weight);
1230 // init_safety() initizes the king safety evaluation, based on UCI
1231 // parameters. It is called from read_weights().
1233 void init_safety() {
1235 QueenContactCheckBonus = get_option_value_int("Queen Contact Check Bonus");
1236 QueenCheckBonus = get_option_value_int("Queen Check Bonus");
1237 RookCheckBonus = get_option_value_int("Rook Check Bonus");
1238 BishopCheckBonus = get_option_value_int("Bishop Check Bonus");
1239 KnightCheckBonus = get_option_value_int("Knight Check Bonus");
1240 DiscoveredCheckBonus = get_option_value_int("Discovered Check Bonus");
1241 MateThreatBonus = get_option_value_int("Mate Threat Bonus");
1243 int maxSlope = get_option_value_int("King Safety Max Slope");
1244 int peak = get_option_value_int("King Safety Max Value") * 256 / 100;
1245 double a = get_option_value_int("King Safety Coefficient") / 100.0;
1246 double b = get_option_value_int("King Safety X Intercept");
1247 bool quad = (get_option_value_string("King Safety Curve") == "Quadratic");
1248 bool linear = (get_option_value_string("King Safety Curve") == "Linear");
1250 for (int i = 0; i < 100; i++)
1253 SafetyTable[i] = Value(0);
1255 SafetyTable[i] = Value((int)(a * (i - b) * (i - b)));
1257 SafetyTable[i] = Value((int)(100 * a * (i - b)));
1260 for (int i = 0; i < 100; i++)
1262 if (SafetyTable[i+1] - SafetyTable[i] > maxSlope)
1263 for (int j = i + 1; j < 100; j++)
1264 SafetyTable[j] = SafetyTable[j-1] + Value(maxSlope);
1266 if (SafetyTable[i] > Value(peak))
1267 SafetyTable[i] = Value(peak);