// Evaluation weights, initialized from UCI options
enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem };
- Score Weights[6];
+ struct Weight { int mg, eg; } Weights[6];
typedef Value V;
#define S(mg, eg) make_score(mg, eg)
// friendly pieces.
const Score MobilityBonus[][32] = {
{}, {},
- { S(-35,-30), S(-22,-20), S(-9,-10), S( 3, 0), S(15, 10), S(27, 20), // Knights
+ { S(-65,-50), S(-42,-30), S(-9,-10), S( 3, 0), S(15, 10), S(27, 20), // Knights
S( 37, 28), S( 42, 31), S(44, 33) },
- { S(-22,-27), S( -8,-13), S( 6, 1), S(20, 15), S(34, 29), S(48, 43), // Bishops
+ { S(-52,-47), S(-28,-23), S( 6, 1), S(20, 15), S(34, 29), S(48, 43), // Bishops
S( 60, 55), S( 68, 63), S(74, 68), S(77, 72), S(80, 75), S(82, 77),
S( 84, 79), S( 86, 81) },
- { S(-17,-33), S(-11,-16), S(-5, 0), S( 1, 16), S( 7, 32), S(13, 48), // Rooks
+ { S(-47,-53), S(-31,-26), S(-5, 0), S( 1, 16), S( 7, 32), S(13, 48), // Rooks
S( 18, 64), S( 22, 80), S(26, 96), S(29,109), S(31,115), S(33,119),
S( 35,122), S( 36,123), S(37,124) },
- { S(-12,-20), S( -8,-13), S(-5, -7), S(-2, -1), S( 1, 5), S( 4, 11), // Queens
- S( 7, 17), S( 10, 23), S(13, 29), S(16, 34), S(18, 38), S(20, 40),
+ { S(-42,-40), S(-28,-23), S(-5, -7), S( 0, 0), S( 6, 10), S(11, 19), // Queens
+ S( 13, 29), S( 18, 38), S(20, 40), S(21, 41), S(22, 41), S(22, 41),
S( 22, 41), S( 23, 41), S(24, 41), S(25, 41), S(25, 41), S(25, 41),
S( 25, 41), S( 25, 41), S(25, 41), S(25, 41), S(25, 41), S(25, 41),
S( 25, 41), S( 25, 41), S(25, 41), S(25, 41) }
const Score Tempo = make_score(24, 11);
const Score RookOn7th = make_score(11, 20);
- const Score QueenOn7th = make_score( 3, 8);
const Score RookOnPawn = make_score(10, 28);
- const Score QueenOnPawn = make_score( 4, 20);
const Score RookOpenFile = make_score(43, 21);
const Score RookSemiopenFile = make_score(19, 10);
const Score BishopPawns = make_score( 8, 12);
// scores, indexed by color and by a calculated integer number.
Score KingDanger[COLOR_NB][128];
- // Function prototypes
- template<bool Trace>
- Value do_evaluate(const Position& pos);
-
- template<Color Us>
- void init_eval_info(const Position& pos, EvalInfo& ei);
-
- template<Color Us, bool Trace>
- Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility);
-
- template<Color Us, bool Trace>
- Score evaluate_king(const Position& pos, const EvalInfo& ei);
-
- template<Color Us, bool Trace>
- Score evaluate_threats(const Position& pos, const EvalInfo& ei);
-
- template<Color Us, bool Trace>
- Score evaluate_passed_pawns(const Position& pos, const EvalInfo& ei);
-
- template<Color Us>
- int evaluate_space(const Position& pos, const EvalInfo& ei);
-
- Score evaluate_unstoppable_pawns(const Position& pos, Color us, const EvalInfo& ei);
-
- Value interpolate(const Score& v, Phase ph, ScaleFactor sf);
- Score apply_weight(Score v, Score w);
- Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight);
-}
-
-
-namespace Eval {
-
- /// evaluate() is the main evaluation function. It always computes two
- /// values, an endgame score and a middlegame score, and interpolates
- /// between them based on the remaining material.
-
- Value evaluate(const Position& pos) {
- return do_evaluate<false>(pos);
- }
-
- /// trace() is like evaluate(), but instead of returning a value, it returns
- /// a string (suitable for outputting to stdout) that contains the detailed
- /// descriptions and values of each evaluation term. It's mainly used for
- /// debugging.
- std::string trace(const Position& pos) {
- return Tracing::do_trace(pos);
+ // apply_weight() weighs score 'v' by weight 'w' trying to prevent overflow
+ Score apply_weight(Score v, const Weight& w) {
+ return make_score(mg_value(v) * w.mg / 256, eg_value(v) * w.eg / 256);
}
- /// init() computes evaluation weights from the corresponding UCI parameters
- /// and setup king tables.
-
- void init() {
-
- Weights[Mobility] = weight_option("Mobility (Midgame)", "Mobility (Endgame)", WeightsInternal[Mobility]);
- Weights[PawnStructure] = weight_option("Pawn Structure (Midgame)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
- Weights[PassedPawns] = weight_option("Passed Pawns (Midgame)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
- Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
- Weights[KingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
- Weights[KingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
+ // weight_option() computes the value of an evaluation weight, by combining
+ // two UCI-configurable weights (midgame and endgame) with an internal weight.
- const int MaxSlope = 30;
- const int Peak = 1280;
+ Weight weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
- for (int t = 0, i = 1; i < 100; ++i)
- {
- t = std::min(Peak, std::min(int(0.4 * i * i), t + MaxSlope));
-
- KingDanger[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]);
- KingDanger[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]);
- }
+ Weight w = { Options[mgOpt] * mg_value(internalWeight) / 100,
+ Options[egOpt] * eg_value(internalWeight) / 100 };
+ return w;
}
-} // namespace Eval
-
-
-namespace {
-
-template<bool Trace>
-Value do_evaluate(const Position& pos) {
-
- assert(!pos.checkers());
-
- EvalInfo ei;
- Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO };
- Thread* thisThread = pos.this_thread();
-
- // Initialize score by reading the incrementally updated scores included
- // in the position object (material + piece square tables) and adding a
- // Tempo bonus. Score is computed from the point of view of white.
- score = pos.psq_score() + (pos.side_to_move() == WHITE ? Tempo : -Tempo);
- // Probe the material hash table
- ei.mi = Material::probe(pos, thisThread->materialTable, thisThread->endgames);
- score += ei.mi->material_value();
-
- // If we have a specialized evaluation function for the current material
- // configuration, call it and return.
- if (ei.mi->specialized_eval_exists())
- return ei.mi->evaluate(pos);
-
- // Probe the pawn hash table
- ei.pi = Pawns::probe(pos, thisThread->pawnsTable);
- score += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
-
- // Initialize attack and king safety bitboards
- init_eval_info<WHITE>(pos, ei);
- init_eval_info<BLACK>(pos, ei);
-
- // Evaluate pieces and mobility
- score += evaluate_pieces<WHITE, Trace>(pos, ei, mobility)
- - evaluate_pieces<BLACK, Trace>(pos, ei, mobility);
-
- score += apply_weight(mobility[WHITE] - mobility[BLACK], Weights[Mobility]);
-
- // Evaluate kings after all other pieces because we need complete attack
- // information when computing the king safety evaluation.
- score += evaluate_king<WHITE, Trace>(pos, ei)
- - evaluate_king<BLACK, Trace>(pos, ei);
-
- // Evaluate tactical threats, we need full attack information including king
- score += evaluate_threats<WHITE, Trace>(pos, ei)
- - evaluate_threats<BLACK, Trace>(pos, ei);
-
- // Evaluate passed pawns, we need full attack information including king
- score += evaluate_passed_pawns<WHITE, Trace>(pos, ei)
- - evaluate_passed_pawns<BLACK, Trace>(pos, ei);
-
- // If one side has only a king, score for potential unstoppable pawns
- if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
- score += evaluate_unstoppable_pawns(pos, WHITE, ei)
- - evaluate_unstoppable_pawns(pos, BLACK, ei);
-
- // Evaluate space for both sides, only in middlegame
- if (ei.mi->space_weight())
- {
- int s = evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei);
- score += apply_weight(s * ei.mi->space_weight(), Weights[Space]);
- }
-
- // Scale winning side if position is more drawish than it appears
- ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE)
- : ei.mi->scale_factor(pos, BLACK);
+ // interpolate() interpolates between a middlegame and an endgame score,
+ // based on game phase. It also scales the return value by a ScaleFactor array.
- // If we don't already have an unusual scale factor, check for opposite
- // colored bishop endgames, and use a lower scale for those.
- if ( ei.mi->game_phase() < PHASE_MIDGAME
- && pos.opposite_bishops()
- && (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN))
- {
- // Ignoring any pawns, do both sides only have a single bishop and no
- // other pieces?
- if ( pos.non_pawn_material(WHITE) == BishopValueMg
- && pos.non_pawn_material(BLACK) == BishopValueMg)
- {
- // Check for KBP vs KB with only a single pawn that is almost
- // certainly a draw or at least two pawns.
- bool one_pawn = (pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK) == 1);
- sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
- }
- else
- // Endgame with opposite-colored bishops, but also other pieces. Still
- // a bit drawish, but not as drawish as with only the two bishops.
- sf = ScaleFactor(50 * sf / SCALE_FACTOR_NORMAL);
- }
+ Value interpolate(const Score& v, Phase ph, ScaleFactor sf) {
- Value v = interpolate(score, ei.mi->game_phase(), sf);
+ assert(-VALUE_INFINITE < mg_value(v) && mg_value(v) < VALUE_INFINITE);
+ assert(-VALUE_INFINITE < eg_value(v) && eg_value(v) < VALUE_INFINITE);
+ assert(PHASE_ENDGAME <= ph && ph <= PHASE_MIDGAME);
- // In case of tracing add all single evaluation contributions for both white and black
- if (Trace)
- {
- Tracing::add_term(Tracing::PST, pos.psq_score());
- Tracing::add_term(Tracing::IMBALANCE, ei.mi->material_value());
- Tracing::add_term(PAWN, ei.pi->pawns_value());
- Score w = ei.mi->space_weight() * evaluate_space<WHITE>(pos, ei);
- Score b = ei.mi->space_weight() * evaluate_space<BLACK>(pos, ei);
- Tracing::add_term(Tracing::SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
- Tracing::add_term(Tracing::TOTAL, score);
- Tracing::ei = ei;
- Tracing::sf = sf;
+ int eg = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
+ return Value((mg_value(v) * int(ph) + eg * int(PHASE_MIDGAME - ph)) / PHASE_MIDGAME);
}
- return pos.side_to_move() == WHITE ? v : -v;
-}
-
// init_eval_info() initializes king bitboards for given color adding
// pawn attacks. To be done at the beginning of the evaluation.
ei.pinnedPieces[Us] = pos.pinned_pieces(Us);
Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
- ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
+ ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
// Init king safety tables only if we are going to use them
if (pos.count<QUEEN>(Us) && pos.non_pawn_material(Us) > QueenValueMg + PawnValueMg)
// evaluate_pieces() assigns bonuses and penalties to the pieces of a given color
template<PieceType Pt, Color Us, bool Trace>
- Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, Bitboard mobilityArea) {
+ Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, Bitboard* mobilityArea) {
Bitboard b;
Square s;
Score score = SCORE_ZERO;
+ const PieceType NextPt = (Us == WHITE ? Pt : PieceType(Pt + 1));
const Color Them = (Us == WHITE ? BLACK : WHITE);
const Square* pl = pos.list<Pt>(Us);
if (ei.pinnedPieces[Us] & s)
b &= LineBB[pos.king_square(Us)][s];
- ei.attackedBy[Us][Pt] |= b;
+ ei.attackedBy[Us][ALL_PIECES] |= ei.attackedBy[Us][Pt] |= b;
if (b & ei.kingRing[Them])
{
ei.kingAdjacentZoneAttacksCount[Us] += popcount<Max15>(bb);
}
- int mob = Pt != QUEEN ? popcount<Max15>(b & mobilityArea)
- : popcount<Full >(b & mobilityArea);
+ if (Pt == QUEEN)
+ b &= ~( ei.attackedBy[Them][KNIGHT]
+ | ei.attackedBy[Them][BISHOP]
+ | ei.attackedBy[Them][ROOK]);
+
+ int mob = Pt != QUEEN ? popcount<Max15>(b & mobilityArea[Us])
+ : popcount<Full >(b & mobilityArea[Us]);
mobility[Us] += MobilityBonus[Pt][mob];
score += MinorBehindPawn;
}
- if ( (Pt == ROOK || Pt == QUEEN)
- && relative_rank(Us, s) >= RANK_5)
+ if (Pt == ROOK)
{
- // Major piece on 7th rank and enemy king trapped on 8th
+ // Rook on 7th rank and enemy king trapped on 8th
if ( relative_rank(Us, s) == RANK_7
&& relative_rank(Us, pos.king_square(Them)) == RANK_8)
- score += Pt == ROOK ? RookOn7th : QueenOn7th;
+ score += RookOn7th;
- // Major piece attacking enemy pawns on the same rank/file
- Bitboard pawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s];
- if (pawns)
- score += popcount<Max15>(pawns) * (Pt == ROOK ? RookOnPawn : QueenOnPawn);
- }
+ // Rook piece attacking enemy pawns on the same rank/file
+ if (relative_rank(Us, s) >= RANK_5)
+ {
+ Bitboard pawns = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s];
+ if (pawns)
+ score += popcount<Max15>(pawns) * RookOnPawn;
+ }
- // Special extra evaluation for rooks
- if (Pt == ROOK)
- {
// Give a bonus for a rook on a open or semi-open file
- if (ei.pi->semiopen(Us, file_of(s)))
- score += ei.pi->semiopen(Them, file_of(s)) ? RookOpenFile : RookSemiopenFile;
+ if (ei.pi->semiopen_file(Us, file_of(s)))
+ score += ei.pi->semiopen_file(Them, file_of(s)) ? RookOpenFile : RookSemiopenFile;
- if (mob > 3 || ei.pi->semiopen(Us, file_of(s)))
+ if (mob > 3 || ei.pi->semiopen_file(Us, file_of(s)))
continue;
Square ksq = pos.king_square(Us);
// king has lost its castling capability.
if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
&& (rank_of(ksq) == rank_of(s) || relative_rank(Us, ksq) == RANK_1)
- && !ei.pi->semiopen_on_side(Us, file_of(ksq), file_of(ksq) < FILE_E))
- score -= (TrappedRook - make_score(mob * 8, 0)) * (pos.can_castle(Us) ? 1 : 2);
+ && !ei.pi->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq)))
+ score -= (TrappedRook - make_score(mob * 8, 0)) * (1 + !pos.can_castle(Us));
}
// An important Chess960 pattern: A cornered bishop blocked by a friendly
if (Trace)
Tracing::terms[Us][Pt] = score;
- return score;
+ return score - evaluate_pieces<NextPt, Them, Trace>(pos, ei, mobility, mobilityArea);
}
-
- // evaluate_pieces() assigns bonuses and penalties to all the
- // pieces of a given color.
-
- template<Color Us, bool Trace>
- Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility) {
-
- const Color Them = (Us == WHITE ? BLACK : WHITE);
-
- // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
- const Bitboard mobilityArea = ~(ei.attackedBy[Them][PAWN] | pos.pieces(Us, PAWN, KING));
-
- Score score = evaluate_pieces<KNIGHT, Us, Trace>(pos, ei, mobility, mobilityArea)
- + evaluate_pieces<BISHOP, Us, Trace>(pos, ei, mobility, mobilityArea)
- + evaluate_pieces<ROOK, Us, Trace>(pos, ei, mobility, mobilityArea)
- + evaluate_pieces<QUEEN, Us, Trace>(pos, ei, mobility, mobilityArea);
-
- // Sum up all attacked squares (updated in evaluate_pieces)
- ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT]
- | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK]
- | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING];
- if (Trace)
- Tracing::terms[Us][Tracing::MOBILITY] = apply_weight(mobility[Us], Weights[Mobility]);
-
- return score;
- }
+ template<>
+ Score evaluate_pieces<KING, WHITE, false>(const Position&, EvalInfo&, Score*, Bitboard*) { return SCORE_ZERO; }
+ template<>
+ Score evaluate_pieces<KING, WHITE, true>(const Position&, EvalInfo&, Score*, Bitboard*) { return SCORE_ZERO; }
// evaluate_king() assigns bonuses and penalties to a king of a given color
// the pawn shelter (current 'score' value).
attackUnits = std::min(20, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
+ 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount<Max15>(undefended))
+ + 2 * (ei.pinnedPieces[Us] != 0)
- mg_value(score) / 32;
// Analyse the enemy's safe queen contact checks. Firstly, find the
const Color Them = (Us == WHITE ? BLACK : WHITE);
- Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns;
+ Bitboard b, squaresToQueen, defendedSquares, unsafeSquares;
Score score = SCORE_ZERO;
b = ei.pi->passed_pawns(Us);
else
defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES];
- // If there aren't any enemy attacks, then assign a huge bonus.
- // The bonus will be a bit smaller if at least the block square
- // isn't attacked, otherwise assign the smallest possible bonus.
- int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 3;
+ // If there aren't any enemy attacks, assign a big bonus. Otherwise
+ // assign a smaller bonus if the block square isn't attacked.
+ int k = !unsafeSquares ? 15 : !(unsafeSquares & blockSq) ? 9 : 0;
- // Assign a big bonus if the path to the queen is fully defended,
- // otherwise assign a bit less of a bonus if at least the block
- // square is defended.
+ // If the path to queen is fully defended, assign a big bonus.
+ // Otherwise assign a smaller bonus if the block square is defended.
if (defendedSquares == squaresToQueen)
k += 6;
else if (defendedSquares & blockSq)
- k += (unsafeSquares & defendedSquares) == unsafeSquares ? 4 : 2;
+ k += 4;
mbonus += Value(k * rr), ebonus += Value(k * rr);
}
} // rr != 0
- // Increase the bonus if the passed pawn is supported by a friendly pawn
- // on the same rank and a bit smaller if it's on the previous rank.
- supportingPawns = pos.pieces(Us, PAWN) & adjacent_files_bb(file_of(s));
- if (supportingPawns & rank_bb(s))
- ebonus += Value(r * 20);
-
- else if (supportingPawns & rank_bb(s - pawn_push(Us)))
- ebonus += Value(r * 12);
-
// 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,
}
- // interpolate() interpolates between a middlegame and an endgame score,
- // based on game phase. It also scales the return value by a ScaleFactor array.
+ // do_evaluate() is the evaluation entry point, called directly from evaluate()
- Value interpolate(const Score& v, Phase ph, ScaleFactor sf) {
+ template<bool Trace>
+ Value do_evaluate(const Position& pos) {
- assert(-VALUE_INFINITE < mg_value(v) && mg_value(v) < VALUE_INFINITE);
- assert(-VALUE_INFINITE < eg_value(v) && eg_value(v) < VALUE_INFINITE);
- assert(PHASE_ENDGAME <= ph && ph <= PHASE_MIDGAME);
+ assert(!pos.checkers());
- int eg = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
- return Value((mg_value(v) * int(ph) + eg * int(PHASE_MIDGAME - ph)) / PHASE_MIDGAME);
- }
+ EvalInfo ei;
+ Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO };
+ Thread* thisThread = pos.this_thread();
- // apply_weight() weights score v by score w trying to prevent overflow
- Score apply_weight(Score v, Score w) {
+ // Initialize score by reading the incrementally updated scores included
+ // in the position object (material + piece square tables) and adding a
+ // Tempo bonus. Score is computed from the point of view of white.
+ score = pos.psq_score() + (pos.side_to_move() == WHITE ? Tempo : -Tempo);
- return make_score((int(mg_value(v)) * mg_value(w)) / 0x100,
- (int(eg_value(v)) * eg_value(w)) / 0x100);
- }
+ // Probe the material hash table
+ ei.mi = Material::probe(pos, thisThread->materialTable, thisThread->endgames);
+ score += ei.mi->material_value();
- // weight_option() computes the value of an evaluation weight, by combining
- // two UCI-configurable weights (midgame and endgame) with an internal weight.
+ // If we have a specialized evaluation function for the current material
+ // configuration, call it and return.
+ if (ei.mi->specialized_eval_exists())
+ return ei.mi->evaluate(pos);
+
+ // Probe the pawn hash table
+ ei.pi = Pawns::probe(pos, thisThread->pawnsTable);
+ score += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]);
+
+ // Initialize attack and king safety bitboards
+ init_eval_info<WHITE>(pos, ei);
+ init_eval_info<BLACK>(pos, ei);
+
+ ei.attackedBy[WHITE][ALL_PIECES] |= ei.attackedBy[WHITE][KING];
+ ei.attackedBy[BLACK][ALL_PIECES] |= ei.attackedBy[BLACK][KING];
+
+ // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
+ Bitboard mobilityArea[] = { ~(ei.attackedBy[BLACK][PAWN] | pos.pieces(WHITE, PAWN, KING)),
+ ~(ei.attackedBy[WHITE][PAWN] | pos.pieces(BLACK, PAWN, KING)) };
+
+ // Evaluate pieces and mobility
+ score += evaluate_pieces<KNIGHT, WHITE, Trace>(pos, ei, mobility, mobilityArea);
+ score += apply_weight(mobility[WHITE] - mobility[BLACK], Weights[Mobility]);
+
+ // Evaluate kings after all other pieces because we need complete attack
+ // information when computing the king safety evaluation.
+ score += evaluate_king<WHITE, Trace>(pos, ei)
+ - evaluate_king<BLACK, Trace>(pos, ei);
+
+ // Evaluate tactical threats, we need full attack information including king
+ score += evaluate_threats<WHITE, Trace>(pos, ei)
+ - evaluate_threats<BLACK, Trace>(pos, ei);
+
+ // Evaluate passed pawns, we need full attack information including king
+ score += evaluate_passed_pawns<WHITE, Trace>(pos, ei)
+ - evaluate_passed_pawns<BLACK, Trace>(pos, ei);
- Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight) {
+ // If one side has only a king, score for potential unstoppable pawns
+ if (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK))
+ score += evaluate_unstoppable_pawns(pos, WHITE, ei)
+ - evaluate_unstoppable_pawns(pos, BLACK, ei);
- // Scale option value from 100 to 256
- int mg = Options[mgOpt] * 256 / 100;
- int eg = Options[egOpt] * 256 / 100;
+ // Evaluate space for both sides, only in middlegame
+ if (ei.mi->space_weight())
+ {
+ int s = evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei);
+ score += apply_weight(s * ei.mi->space_weight(), Weights[Space]);
+ }
+
+ // Scale winning side if position is more drawish than it appears
+ ScaleFactor sf = eg_value(score) > VALUE_DRAW ? ei.mi->scale_factor(pos, WHITE)
+ : ei.mi->scale_factor(pos, BLACK);
+
+ // If we don't already have an unusual scale factor, check for opposite
+ // colored bishop endgames, and use a lower scale for those.
+ if ( ei.mi->game_phase() < PHASE_MIDGAME
+ && pos.opposite_bishops()
+ && (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN))
+ {
+ // Ignoring any pawns, do both sides only have a single bishop and no
+ // other pieces?
+ if ( pos.non_pawn_material(WHITE) == BishopValueMg
+ && pos.non_pawn_material(BLACK) == BishopValueMg)
+ {
+ // Check for KBP vs KB with only a single pawn that is almost
+ // certainly a draw or at least two pawns.
+ bool one_pawn = (pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK) == 1);
+ sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
+ }
+ else
+ // Endgame with opposite-colored bishops, but also other pieces. Still
+ // a bit drawish, but not as drawish as with only the two bishops.
+ sf = ScaleFactor(50 * sf / SCALE_FACTOR_NORMAL);
+ }
- return apply_weight(make_score(mg, eg), internalWeight);
+ Value v = interpolate(score, ei.mi->game_phase(), sf);
+
+ // In case of tracing add all single evaluation contributions for both white and black
+ if (Trace)
+ {
+ Tracing::add_term(Tracing::PST, pos.psq_score());
+ Tracing::add_term(Tracing::IMBALANCE, ei.mi->material_value());
+ Tracing::add_term(PAWN, ei.pi->pawns_value());
+ Tracing::add_term(Tracing::MOBILITY, apply_weight(mobility[WHITE], Weights[Mobility])
+ , apply_weight(mobility[BLACK], Weights[Mobility]));
+ Score w = ei.mi->space_weight() * evaluate_space<WHITE>(pos, ei);
+ Score b = ei.mi->space_weight() * evaluate_space<BLACK>(pos, ei);
+ Tracing::add_term(Tracing::SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space]));
+ Tracing::add_term(Tracing::TOTAL, score);
+ Tracing::ei = ei;
+ Tracing::sf = sf;
+ }
+
+ return pos.side_to_move() == WHITE ? v : -v;
}
// Tracing function definitions
- double Tracing::to_cp(Value v) { return double(v) / PawnValueMg; }
+ double Tracing::to_cp(Value v) { return double(v) / PawnValueEg; }
void Tracing::add_term(int idx, Score wScore, Score bScore) {
switch (idx) {
case PST: case IMBALANCE: case PAWN: case TOTAL:
ss << std::setw(20) << name << " | --- --- | --- --- | "
- << std::setw(6) << to_cp(mg_value(wScore)) << " "
- << std::setw(6) << to_cp(eg_value(wScore)) << " \n";
+ << std::setw(5) << to_cp(mg_value(wScore - bScore)) << " "
+ << std::setw(5) << to_cp(eg_value(wScore - bScore)) << " \n";
break;
default:
ss << std::setw(20) << name << " | " << std::noshowpos
<< std::setw(5) << to_cp(eg_value(wScore)) << " | "
<< std::setw(5) << to_cp(mg_value(bScore)) << " "
<< std::setw(5) << to_cp(eg_value(bScore)) << " | "
- << std::showpos
- << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " "
- << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n";
+ << std::setw(5) << to_cp(mg_value(wScore - bScore)) << " "
+ << std::setw(5) << to_cp(eg_value(wScore - bScore)) << " \n";
}
}
std::memset(terms, 0, sizeof(terms));
Value v = do_evaluate<true>(pos);
+ v = pos.side_to_move() == WHITE ? v : -v; // White's point of view
std::stringstream ss;
- ss << std::showpoint << std::showpos << std::fixed << std::setprecision(2)
- << " Eval term | White | Black | Total \n"
- << " | MG EG | MG EG | MG EG \n"
- << "---------------------+-------------+-------------+---------------\n";
+ ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2)
+ << " Eval term | White | Black | Total \n"
+ << " | MG EG | MG EG | MG EG \n"
+ << "---------------------+-------------+-------------+-------------\n";
format_row(ss, "Material, PST, Tempo", PST);
format_row(ss, "Material imbalance", IMBALANCE);
format_row(ss, "Passed pawns", PASSED);
format_row(ss, "Space", SPACE);
- ss << "---------------------+-------------+-------------+---------------\n";
+ ss << "---------------------+-------------+-------------+-------------\n";
format_row(ss, "Total", TOTAL);
- ss << "\nScaling: " << std::noshowpos
- << std::setw(6) << 100.0 * ei.mi->game_phase() / 128.0 << "% MG, "
- << std::setw(6) << 100.0 * (1.0 - ei.mi->game_phase() / 128.0) << "% * "
- << std::setw(6) << (100.0 * sf) / SCALE_FACTOR_NORMAL << "% EG.\n"
- << "Total evaluation: " << to_cp(v);
+ ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n";
return ss.str();
}
-}
+
+} // namespace
+
+
+namespace Eval {
+
+ /// evaluate() is the main evaluation function. It returns a static evaluation
+ /// of the position always from the point of view of the side to move.
+
+ Value evaluate(const Position& pos) {
+ return do_evaluate<false>(pos);
+ }
+
+
+ /// trace() is like evaluate(), but instead of returning a value, it returns
+ /// a string (suitable for outputting to stdout) that contains the detailed
+ /// descriptions and values of each evaluation term. It's mainly used for
+ /// debugging.
+ std::string trace(const Position& pos) {
+ return Tracing::do_trace(pos);
+ }
+
+
+ /// init() computes evaluation weights from the corresponding UCI parameters
+ /// and setup king tables.
+
+ void init() {
+
+ Weights[Mobility] = weight_option("Mobility (Midgame)", "Mobility (Endgame)", WeightsInternal[Mobility]);
+ Weights[PawnStructure] = weight_option("Pawn Structure (Midgame)", "Pawn Structure (Endgame)", WeightsInternal[PawnStructure]);
+ Weights[PassedPawns] = weight_option("Passed Pawns (Midgame)", "Passed Pawns (Endgame)", WeightsInternal[PassedPawns]);
+ Weights[Space] = weight_option("Space", "Space", WeightsInternal[Space]);
+ Weights[KingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]);
+ Weights[KingDangerThem] = weight_option("Aggressiveness", "Aggressiveness", WeightsInternal[KingDangerThem]);
+
+ const int MaxSlope = 30;
+ const int Peak = 1280;
+
+ for (int t = 0, i = 1; i < 100; ++i)
+ {
+ t = std::min(Peak, std::min(int(0.4 * i * i), t + MaxSlope));
+
+ KingDanger[1][i] = apply_weight(make_score(t, 0), Weights[KingDangerUs]);
+ KingDanger[0][i] = apply_weight(make_score(t, 0), Weights[KingDangerThem]);
+ }
+ }
+
+} // namespace Eval
projects / stockfish / blobdiff