/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2009 Marco Costalba
+ Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
const int GrainSize = 8;
// Evaluation weights, initialized from UCI options
- Score WeightMobility, WeightPawnStructure;
- Score WeightPassedPawns, WeightSpace;
- Score WeightKingSafety[2];
+ enum { Mobility, PawnStructure, PassedPawns, Space, KingSafetyUs, KingSafetyThem };
+ Score Weights[6];
+
+ typedef Value V;
+ #define S(mg, eg) make_score(mg, eg)
// Internal evaluation weights. These are applied on top of the evaluation
// weights read from UCI parameters. The purpose is to be able to change
// parameters at 100, which looks prettier.
//
// Values modified by Joona Kiiski
- const Score WeightMobilityInternal = make_score(248, 271);
- const Score WeightPawnStructureInternal = make_score(233, 201);
- const Score WeightPassedPawnsInternal = make_score(252, 259);
- const Score WeightSpaceInternal = make_score( 46, 0);
- const Score WeightKingSafetyInternal = make_score(247, 0);
- const Score WeightKingOppSafetyInternal = make_score(259, 0);
-
- // Mobility and outposts bonus modified by Joona Kiiski
-
- typedef Value V;
- #define S(mg, eg) make_score(mg, eg)
-
- CACHE_LINE_ALIGNMENT
+ const Score WeightsInternal[] = {
+ S(248, 271), S(233, 201), S(252, 259), S(46, 0), S(247, 0), S(259, 0)
+ };
// Knight mobility bonus in middle game and endgame, indexed by the number
// of attacked squares not occupied by friendly piecess.
const int AttackWeight[] = { 0, 0, KnightAttackWeight, BishopAttackWeight, RookAttackWeight, QueenAttackWeight };
- // Bonuses for safe checks, initialized from UCI options
- int QueenContactCheckBonus, DiscoveredCheckBonus;
- int QueenCheckBonus, RookCheckBonus, BishopCheckBonus, KnightCheckBonus;
+ // Bonuses for safe checks
+ const int QueenContactCheckBonus = 3;
+ const int DiscoveredCheckBonus = 3;
+ const int QueenCheckBonus = 2;
+ const int RookCheckBonus = 1;
+ const int BishopCheckBonus = 1;
+ const int KnightCheckBonus = 1;
// Scan for queen contact mates?
const bool QueenContactMates = true;
- // Bonus for having a mate threat, initialized from UCI options
- int MateThreatBonus;
+ // Bonus for having a mate threat
+ const int MateThreatBonus = 3;
// InitKingDanger[] contains bonuses based on the position of the defending
// king.
15, 15, 15, 15, 15, 15, 15, 15
};
- // SafetyTable[] contains the actual king safety scores. It is initialized
- // in init_safety().
- Value SafetyTable[100];
+ // SafetyTable[color][] contains the actual king safety weighted scores
+ Score SafetyTable[2][128];
// Pawn and material hash tables, indexed by the current thread id.
// Note that they will be initialized at 0 being global variables.
template<Color Us, bool HasPopCnt>
void evaluate_space(const Position& pos, EvalInfo& ei);
+ template<Color Us>
void evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
+
+ void evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei);
void evaluate_trapped_bishop_a7h7(const Position& pos, Square s, Color us, EvalInfo& ei);
void evaluate_trapped_bishop_a1h1(const Position& pos, Square s, Color us, EvalInfo& ei);
inline Score apply_weight(Score v, Score weight);
template<bool HasPopCnt>
Value do_evaluate(const Position& pos, EvalInfo& ei, int threadID) {
+ Bitboard b;
+ ScaleFactor factor[2];
+
assert(pos.is_ok());
assert(threadID >= 0 && threadID < MAX_THREADS);
assert(!pos.is_check());
return ei.mi->evaluate(pos);
// After get_material_info() call that modifies them
- ScaleFactor factor[2];
factor[WHITE] = ei.mi->scale_factor(pos, WHITE);
factor[BLACK] = ei.mi->scale_factor(pos, BLACK);
// Probe the pawn hash table
ei.pi = PawnTable[threadID]->get_pawn_info(pos);
- ei.value += apply_weight(ei.pi->pawns_value(), WeightPawnStructure);
+ ei.value += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
// Initialize king attack bitboards and king attack zones for both sides
ei.attackedBy[WHITE][KING] = pos.attacks_from<KING>(pos.king_square(WHITE));
// Initialize pawn attack bitboards for both sides
ei.attackedBy[WHITE][PAWN] = ei.pi->pawn_attacks(WHITE);
- ei.attackedBy[BLACK][PAWN] = ei.pi->pawn_attacks(BLACK);
- Bitboard b1 = ei.attackedBy[WHITE][PAWN] & ei.attackedBy[BLACK][KING];
- Bitboard b2 = ei.attackedBy[BLACK][PAWN] & ei.attackedBy[WHITE][KING];
- if (b1)
- ei.kingAttackersCount[WHITE] = count_1s_max_15<HasPopCnt>(b1)/2;
+ b = ei.attackedBy[WHITE][PAWN] & ei.attackedBy[BLACK][KING];
+ if (b)
+ ei.kingAttackersCount[WHITE] = count_1s_max_15<HasPopCnt>(b)/2;
- if (b2)
- ei.kingAttackersCount[BLACK] = count_1s_max_15<HasPopCnt>(b2)/2;
+ ei.attackedBy[BLACK][PAWN] = ei.pi->pawn_attacks(BLACK);
+ b = ei.attackedBy[BLACK][PAWN] & ei.attackedBy[WHITE][KING];
+ if (b)
+ ei.kingAttackersCount[BLACK] = count_1s_max_15<HasPopCnt>(b)/2;
// Evaluate pieces
evaluate_pieces_of_color<WHITE, HasPopCnt>(pos, ei);
evaluate_king<WHITE, HasPopCnt>(pos, ei);
evaluate_king<BLACK, HasPopCnt>(pos, ei);
- // Evaluate tactical threats, we need full attack info
+ // Evaluate tactical threats, we need full attack info including king
evaluate_threats<WHITE>(pos, ei);
evaluate_threats<BLACK>(pos, ei);
- // Evaluate passed pawns. We evaluate passed pawns for both sides at once,
- // because we need to know which side promotes first in positions where
- // both sides have an unstoppable passed pawn. To be called after all attacks
- // are computed, included king.
- if (ei.pi->passed_pawns())
- evaluate_passed_pawns(pos, ei);
+ // Evaluate passed pawns, we need full attack info including king
+ evaluate_passed_pawns<WHITE>(pos, ei);
+ evaluate_passed_pawns<BLACK>(pos, ei);
+
+ // If one side has only a king, check whether exsists any unstoppable passed pawn
+ if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
+ evaluate_unstoppable_pawns(pos, ei);
Phase phase = ei.mi->game_phase();
// Middle-game specific evaluation terms
if (phase > PHASE_ENDGAME)
{
- // Pawn storms in positions with opposite castling.
+ // Pawn storms in positions with opposite castling
if ( square_file(pos.king_square(WHITE)) >= FILE_E
&& square_file(pos.king_square(BLACK)) <= FILE_D)
}
// Mobility
- ei.value += apply_weight(ei.mobility, WeightMobility);
+ ei.value += apply_weight(ei.mobility, Weights[Mobility]);
// If we don't already have an unusual scale factor, check for opposite
// colored bishop endgames, and use a lower scale for those
void read_weights(Color us) {
- Color them = opposite_color(us);
+ // King safety is asymmetrical. Our king safety is controled by "Cowardice"
+ // UCI parameter, instead the opponent one by "Aggressiveness".
+ const int kingSafetyUs = (us == WHITE ? KingSafetyUs : KingSafetyThem);
+ const int kingSafetyThem = (us == WHITE ? KingSafetyThem : KingSafetyUs);
- WeightMobility = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightMobilityInternal);
- WeightPawnStructure = weight_option("Pawn Structure (Middle Game)", "Pawn Structure (Endgame)", WeightPawnStructureInternal);
- WeightPassedPawns = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightPassedPawnsInternal);
- WeightSpace = weight_option("Space", "Space", WeightSpaceInternal);
- WeightKingSafety[us] = weight_option("Cowardice", "Cowardice", WeightKingSafetyInternal);
- WeightKingSafety[them] = weight_option("Aggressiveness", "Aggressiveness", WeightKingOppSafetyInternal);
+ Weights[Mobility] = weight_option("Mobility (Middle Game)", "Mobility (Endgame)", WeightsInternal[Mobility]);
+ Weights[PawnStructure] = weight_option("Pawn Structure (Middle Game)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
+ Weights[PassedPawns] = weight_option("Passed Pawns (Middle Game)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
+ Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
+ Weights[kingSafetyUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingSafetyUs]);
+ Weights[kingSafetyThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingSafetyThem]);
// If running in analysis mode, make sure we use symmetrical king safety. We do this
- // by replacing both WeightKingSafety[us] and WeightKingSafety[them] by their average.
+ // by replacing both Weights[kingSafetyUs] and Weights[kingSafetyThem] by their average.
if (get_option_value_bool("UCI_AnalyseMode"))
- {
- WeightKingSafety[us] = (WeightKingSafety[us] + WeightKingSafety[them]) / 2;
- WeightKingSafety[them] = WeightKingSafety[us];
- }
+ Weights[kingSafetyUs] = Weights[kingSafetyThem] = (Weights[kingSafetyUs] + Weights[kingSafetyThem]) / 2;
+
init_safety();
}
attackUnits = Min(99, Max(0, attackUnits));
// Finally, extract the king safety score from the SafetyTable[] array.
- // Add the score to the evaluation, and also to ei.futilityMargin. The
- // reason for adding the king safety score to the futility margin is
- // that the king safety scores can sometimes be very big, and that
+ // Subtract the score from evaluation, and set ei.futilityMargin[].
+ // The reason for storing the king safety score to futility margin
+ // is that the king safety scores can sometimes be very big, and that
// capturing a single attacking piece can therefore result in a score
// change far bigger than the value of the captured piece.
- Score v = apply_weight(make_score(SafetyTable[attackUnits], 0), WeightKingSafety[Us]);
- ei.value -= Sign[Us] * v;
- ei.futilityMargin[Us] += mg_value(v);
+ ei.value -= Sign[Us] * SafetyTable[Us][attackUnits];
+ ei.futilityMargin[Us] = mg_value(SafetyTable[Us][attackUnits]);
}
}
- // evaluate_passed_pawns() evaluates the passed pawns of the given color
+ // evaluate_passed_pawns<>() evaluates the passed pawns of the given color
template<Color Us>
- void evaluate_passed_pawns_of_color(const Position& pos, int movesToGo[], Square pawnToGo[], EvalInfo& ei) {
+ void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
- Bitboard b2, b3, b4;
- Square ourKingSq = pos.king_square(Us);
- Square theirKingSq = pos.king_square(Them);
- Bitboard b = ei.pi->passed_pawns() & pos.pieces(PAWN, Us);
+ Bitboard b = ei.pi->passed_pawns() & pos.pieces_of_color(Us);
while (b)
{
{
Square blockSq = s + pawn_push(Us);
- ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr);
- ebonus -= Value(square_distance(ourKingSq, blockSq + pawn_push(Us)) * 1 * tr);
- ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr);
+ ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 3 * tr);
+ ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * 1 * tr);
+ ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 6 * tr);
// If the pawn is free to advance, increase bonus
if (pos.square_is_empty(blockSq))
{
// There are no enemy pawns in the pawn's path
- b2 = squares_in_front_of(Us, s);
+ Bitboard b2 = squares_in_front_of(Us, s);
assert((b2 & pos.pieces(PAWN, Them)) == EmptyBoardBB);
// Squares attacked by us
- b4 = b2 & ei.attacked_by(Us);
+ Bitboard b4 = b2 & ei.attacked_by(Us);
// Squares attacked or occupied by enemy pieces
- b3 = b2 & (ei.attacked_by(Them) | pos.pieces_of_color(Them));
+ Bitboard b3 = b2 & (ei.attacked_by(Them) | pos.pieces_of_color(Them));
// If there is an enemy rook or queen attacking the pawn from behind,
// add all X-ray attacks by the rook or queen.
} // tr != 0
// If the pawn is supported by a friendly pawn, increase bonus
- b2 = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
- if (b2 & rank_bb(s))
+ Bitboard b1 = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
+ if (b1 & rank_bb(s))
ebonus += Value(r * 20);
- else if (pos.attacks_from<PAWN>(s, Them) & b2)
+ else if (pos.attacks_from<PAWN>(s, Them) & b1)
ebonus += Value(r * 12);
- // If the other side has only a king, check whether the pawn is
- // unstoppable
- if (pos.non_pawn_material(Them) == Value(0))
- {
- Square qsq;
- int d;
-
- qsq = relative_square(Us, make_square(square_file(s), RANK_8));
- d = square_distance(s, qsq)
- - square_distance(theirKingSq, qsq)
- + (Us != pos.side_to_move());
-
- if (d < 0)
- {
- int mtg = RANK_8 - relative_rank(Us, s);
- int blockerCount = count_1s_max_15(squares_in_front_of(Us,s) & pos.occupied_squares());
- mtg += blockerCount;
- d += blockerCount;
- if (d < 0 && (!movesToGo[Us] || movesToGo[Us] > mtg))
- {
- movesToGo[Us] = mtg;
- pawnToGo[Us] = s;
- }
- }
- }
-
// Rook pawns are a special case: They are sometimes worse, and
// sometimes better than other passed pawns. It is difficult to find
// good rules for determining whether they are good or bad. For now,
ebonus -= ebonus / 4;
}
- // Add the scores for this pawn to the middle game and endgame eval.
- ei.value += Sign[Us] * apply_weight(make_score(mbonus, ebonus), WeightPassedPawns);
+ // Add the scores for this pawn to the middle game and endgame eval
+ ei.value += Sign[Us] * apply_weight(make_score(mbonus, ebonus), Weights[PassedPawns]);
} // while
}
- // evaluate_passed_pawns() evaluates the passed pawns for both sides
+ // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides
- void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
+ void evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) {
int movesToGo[2] = {0, 0};
Square pawnToGo[2] = {SQ_NONE, SQ_NONE};
- // Evaluate pawns for each color
- evaluate_passed_pawns_of_color<WHITE>(pos, movesToGo, pawnToGo, ei);
- evaluate_passed_pawns_of_color<BLACK>(pos, movesToGo, pawnToGo, ei);
+ for (Color c = WHITE; c <= BLACK; c++)
+ {
+ // Skip evaluation if other side has non-pawn pieces
+ if (pos.non_pawn_material(opposite_color(c)))
+ continue;
+
+ Bitboard b = ei.pi->passed_pawns() & pos.pieces_of_color(c);
+
+ while (b)
+ {
+ Square s = pop_1st_bit(&b);
+ Square queeningSquare = relative_square(c, make_square(square_file(s), RANK_8));
+ int d = square_distance(s, queeningSquare)
+ - square_distance(pos.king_square(opposite_color(c)), queeningSquare)
+ + int(c != pos.side_to_move());
+
+ if (d < 0)
+ {
+ int mtg = RANK_8 - relative_rank(c, s);
+ int blockerCount = count_1s_max_15(squares_in_front_of(c, s) & pos.occupied_squares());
+ mtg += blockerCount;
+ d += blockerCount;
+ if (d < 0 && (!movesToGo[c] || movesToGo[c] > mtg))
+ {
+ movesToGo[c] = mtg;
+ pawnToGo[c] = s;
+ }
+ }
+ }
+ }
// Neither side has an unstoppable passed pawn?
if (!(movesToGo[WHITE] | movesToGo[BLACK]))
int space = count_1s_max_15<HasPopCnt>(safeSquares)
+ count_1s_max_15<HasPopCnt>(behindFriendlyPawns & safeSquares);
- ei.value += Sign[Us] * apply_weight(make_score(space * ei.mi->space_weight(), 0), WeightSpace);
+ ei.value += Sign[Us] * apply_weight(make_score(space * ei.mi->space_weight(), 0), Weights[Space]);
}
}
// init_safety() initizes the king safety evaluation, based on UCI
- // parameters. It is called from read_weights().
+ // parameters. It is called from read_weights().
void init_safety() {
- QueenContactCheckBonus = get_option_value_int("Queen Contact Check Bonus");
- QueenCheckBonus = get_option_value_int("Queen Check Bonus");
- RookCheckBonus = get_option_value_int("Rook Check Bonus");
- BishopCheckBonus = get_option_value_int("Bishop Check Bonus");
- KnightCheckBonus = get_option_value_int("Knight Check Bonus");
- DiscoveredCheckBonus = get_option_value_int("Discovered Check Bonus");
- MateThreatBonus = get_option_value_int("Mate Threat Bonus");
-
- int maxSlope = get_option_value_int("King Safety Max Slope");
- int peak = get_option_value_int("King Safety Max Value") * 256 / 100;
- double a = get_option_value_int("King Safety Coefficient") / 100.0;
- double b = get_option_value_int("King Safety X Intercept");
- bool quad = (get_option_value_string("King Safety Curve") == "Quadratic");
- bool linear = (get_option_value_string("King Safety Curve") == "Linear");
+ int maxSlope = 30;
+ int peak = 0x500;
+ double a = 0.4;
+ double b = 0.0;
+ Value t[100];
+ // First setup the base table
for (int i = 0; i < 100; i++)
{
if (i < b)
- SafetyTable[i] = Value(0);
- else if (quad)
- SafetyTable[i] = Value((int)(a * (i - b) * (i - b)));
- else if (linear)
- SafetyTable[i] = Value((int)(100 * a * (i - b)));
+ t[i] = Value(0);
+ else
+ t[i] = Value((int)(a * (i - b) * (i - b)));
}
- for (int i = 0; i < 100; i++)
+ for (int i = 1; i < 100; i++)
{
- if (SafetyTable[i+1] - SafetyTable[i] > maxSlope)
- for (int j = i + 1; j < 100; j++)
- SafetyTable[j] = SafetyTable[j-1] + Value(maxSlope);
+ if (t[i] - t[i - 1] > maxSlope)
+ t[i] = t[i - 1] + Value(maxSlope);
- if (SafetyTable[i] > Value(peak))
- SafetyTable[i] = Value(peak);
+ if (t[i] > Value(peak))
+ t[i] = Value(peak);
}
+
+ // Then apply the weights and get the final SafetyTable[] array
+ for (Color c = WHITE; c <= BLACK; c++)
+ for (int i = 0; i < 100; i++)
+ SafetyTable[c][i] = apply_weight(make_score(t[i], 0), Weights[KingSafetyUs + c]);
}
}
projects / stockfish / blobdiff