namespace {
- namespace Tracing {
+ namespace Trace {
enum Term { // First 8 entries are for PieceType
MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERM_NB
};
- Score scores[COLOR_NB][TERM_NB];
+ double scores[TERM_NB][COLOR_NB][PHASE_NB];
- std::ostream& operator<<(std::ostream& os, Term idx);
+ double to_cp(Value v) { return double(v) / PawnValueEg; }
- double to_cp(Value v);
- void write(int idx, Color c, Score s);
- void write(int idx, Score w, Score b = SCORE_ZERO);
- std::string do_trace(const Position& pos);
+ void add(int idx, Color c, Score s) {
+ scores[idx][c][MG] = to_cp(mg_value(s));
+ scores[idx][c][EG] = to_cp(eg_value(s));
+ }
+
+ void add(int idx, Score w, Score b = SCORE_ZERO) {
+ add(idx, WHITE, w); add(idx, BLACK, b);
+ }
+
+ std::ostream& operator<<(std::ostream& os, Term t) {
+
+ if (t == MATERIAL || t == IMBALANCE || t == Term(PAWN) || t == TOTAL)
+ os << " --- --- | --- --- | ";
+ else
+ os << std::setw(5) << scores[t][WHITE][MG] << " "
+ << std::setw(5) << scores[t][WHITE][EG] << " | "
+ << std::setw(5) << scores[t][BLACK][MG] << " "
+ << std::setw(5) << scores[t][BLACK][EG] << " | ";
+
+ os << std::setw(5) << scores[t][WHITE][MG] - scores[t][BLACK][MG] << " "
+ << std::setw(5) << scores[t][WHITE][EG] - scores[t][BLACK][EG] << " \n";
+
+ return os;
+ }
}
+ using namespace Trace;
// Struct EvalInfo contains various information computed and collected
// by the evaluation functions.
struct EvalInfo {
- // Pointers to material and pawn hash table entries
- Material::Entry* mi;
- Pawns::Entry* pi;
-
// attackedBy[color][piece type] is a bitboard representing all squares
- // attacked by a given color and piece type, attackedBy[color][ALL_PIECES]
- // contains all squares attacked by the given color.
+ // attacked by a given color and piece type (can be also ALL_PIECES).
Bitboard attackedBy[COLOR_NB][PIECE_TYPE_NB];
// kingRing[color] is the zone around the king which is considered
int kingAdjacentZoneAttacksCount[COLOR_NB];
Bitboard pinnedPieces[COLOR_NB];
+ Pawns::Entry* pi;
};
S( 94, 99), S( 96,100), S(99,111), S(99,112) }
};
- // Outpost[knight/bishop][supported by pawn]
- const Score Outpost[2][2] = {{S(28,7), S(42,11)}, {S(12,3), S(18,5)}};
+ // Outpost[knight/bishop][supported by pawn] contains bonuses for knights and
+ // bishops outposts, bigger if outpost piece is supported by a pawn.
+ const Score Outpost[][2] = {
+ { S(42,11), S(63,17) }, // Knights
+ { S(18, 5), S(27, 8) } // Bishops
+ };
// Threat[defended/weak][minor/major attacking][attacked PieceType] contains
// bonuses according to which piece type attacks which one.
S(0, 0), S(0, 0), S(107, 138), S(84, 122), S(114, 203), S(121, 217)
};
+ // Passed[mg/eg][rank] contains midgame and endgame bonuses for passed pawns.
+ // We don't use a Score because we process the two components independently.
+ const Value Passed[][RANK_NB] = {
+ { V(0), V( 1), V(34), V(90), V(214), V(328) },
+ { V(7), V(14), V(37), V(63), V(134), V(189) }
+ };
+
const Score ThreatenedByHangingPawn = S(40, 60);
// Assorted bonuses and penalties used by evaluation
const Score Unstoppable = S( 0, 20);
const Score Hanging = S(31, 26);
const Score PawnAttackThreat = S(20, 20);
- const Score PawnSafePush = S( 5, 5);
+ const Score Checked = S(20, 20);
// Penalty for a bishop on a1/h1 (a8/h8 for black) which is trapped by
// a friendly pawn on b2/g2 (b7/g7 for black). This can obviously only
const Square Down = (Us == WHITE ? DELTA_S : DELTA_N);
ei.pinnedPieces[Us] = pos.pinned_pieces(Us);
- ei.attackedBy[Us][ALL_PIECES] = ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us);
- Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.king_square(Them));
+ Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from<KING>(pos.square<KING>(Them));
+ ei.attackedBy[Them][ALL_PIECES] |= b;
+ 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.non_pawn_material(Us) >= QueenValueMg)
// 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) {
+ template<PieceType Pt, Color Us, bool DoTrace>
+ Score evaluate_pieces(const Position& pos, EvalInfo& ei, Score* mobility, const Bitboard* mobilityArea) {
Bitboard b;
Square s;
const PieceType NextPt = (Us == WHITE ? Pt : PieceType(Pt + 1));
const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Square* pl = pos.
list<Pt>(Us);
+ const Square* pl = pos.
squares<Pt>(Us);
ei.attackedBy[Us][Pt] = 0;
: pos.attacks_from<Pt>(s);
if (ei.pinnedPieces[Us] & s)
- b &= LineBB[pos.king_square(Us)][s];
+ b &= LineBB[pos.square<KING>(Us)][s];
ei.attackedBy[Us][ALL_PIECES] |= ei.attackedBy[Us][Pt] |= b;
{
// Bonus for outpost square
if ( relative_rank(Us, s) >= RANK_4
+ && relative_rank(Us, s) <= RANK_6
&& !(pos.pieces(Them, PAWN) & pawn_attack_span(Us, s)))
score += Outpost[Pt == BISHOP][!!(ei.attackedBy[Us][PAWN] & s)];
// Penalize when trapped by the king, even more if king cannot castle
if (mob <= 3 && !ei.pi->semiopen_file(Us, file_of(s)))
{
- Square ksq = pos.king_square(Us);
+ Square ksq = pos.square<KING>(Us);
if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
&& (rank_of(ksq) == rank_of(s) || relative_rank(Us, ksq) == RANK_1)
}
}
- if (Trace)
- Tracing::write(Pt, Us, score);
+ if (DoTrace)
+ Trace::add(Pt, Us, score);
// Recursively call evaluate_pieces() of next piece type until KING excluded
- return score - evaluate_pieces<NextPt, Them, Trace>(pos, ei, mobility, mobilityArea);
+ return score - evaluate_pieces<NextPt, Them, DoTrace>(pos, ei, mobility, mobilityArea);
}
template<>
- Score evaluate_pieces<KING, WHITE, false>(const Position&, EvalInfo&, Score*, Bitboard*) { return SCORE_ZERO; }
+ Score evaluate_pieces<KING, WHITE, false>(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; }
template<>
- Score evaluate_pieces<KING, WHITE, true>(const Position&, EvalInfo&, Score*, Bitboard*) { return SCORE_ZERO; }
+ Score evaluate_pieces<KING, WHITE, true>(const Position&, EvalInfo&, Score*, const Bitboard*) { return SCORE_ZERO; }
// evaluate_king() assigns bonuses and penalties to a king of a given color
- template<Color Us, bool Trace>
+ template<Color Us, bool DoTrace>
Score evaluate_king(const Position& pos, const EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
Bitboard undefended, b, b1, b2, safe;
int attackUnits;
- const Square ksq = pos.king_square(Us);
+ const Square ksq = pos.square<KING>(Us);
// King shelter and enemy pawns storm
Score score = ei.pi->king_safety<Us>(pos, ksq);
attackUnits = std::min(74, ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them])
+ 8 * ei.kingAdjacentZoneAttacksCount[Them]
+ 25 * popcount<Max15>(undefended)
- + 11 * (ei.pinnedPieces[Us] != 0)
- - mg_value(score) / 8
- - !pos.count<QUEEN>(Them) * 60;
+ + 11 * !!ei.pinnedPieces[Us]
+ - 60 * !pos.count<QUEEN>(Them)
+ - mg_value(score) / 8;
// Analyse the enemy's safe queen contact checks. Firstly, find the
// undefended squares around the king reachable by the enemy queen...
// Enemy queen safe checks
b = (b1 | b2) & ei.attackedBy[Them][QUEEN];
if (b)
+ {
attackUnits += QueenCheck * popcount<Max15>(b);
+ score -= Checked;
+ }
// Enemy rooks safe checks
b = b1 & ei.attackedBy[Them][ROOK];
if (b)
+ {
attackUnits += RookCheck * popcount<Max15>(b);
+ score -= Checked;
+ }
// Enemy bishops safe checks
b = b2 & ei.attackedBy[Them][BISHOP];
if (b)
+ {
attackUnits += BishopCheck * popcount<Max15>(b);
+ score -= Checked;
+ }
// Enemy knights safe checks
b = pos.attacks_from<KNIGHT>(ksq) & ei.attackedBy[Them][KNIGHT] & safe;
if (b)
+ {
attackUnits += KnightCheck * popcount<Max15>(b);
+ score -= Checked;
+ }
// Finally, extract the king danger score from the KingDanger[]
// array and subtract the score from evaluation.
score -= KingDanger[std::max(std::min(attackUnits, 399), 0)];
}
- if (Trace)
- Tracing::write(KING, Us, score);
+ if (DoTrace)
+ Trace::add(KING, Us, score);
return score;
}
// evaluate_threats() assigns bonuses according to the type of attacking piece
// and the type of attacked one.
- template<Color Us, bool Trace>
+ template<Color Us, bool DoTrace>
Score evaluate_threats(const Position& pos, const EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
score += more_than_one(b) ? KingOnMany : KingOnOne;
}
- // Add a small bonus for safe pawn pushes
+ // Bonus if some pawns can safely push and attack an enemy piece
b = pos.pieces(Us, PAWN) & ~TRank7BB;
b = shift_bb<Up>(b | (shift_bb<Up>(b & TRank2BB) & ~pos.pieces()));
& ~ei.attackedBy[Them][PAWN]
& (ei.attackedBy[Us][ALL_PIECES] | ~ei.attackedBy[Them][ALL_PIECES]);
- if (b)
- score += popcount<Full>(b) * PawnSafePush;
-
- // Add another bonus if the pawn push attacks an enemy piece
b = (shift_bb<Left>(b) | shift_bb<Right>(b))
& pos.pieces(Them)
& ~ei.attackedBy[Us][PAWN];
if (b)
score += popcount<Max15>(b) * PawnAttackThreat;
- if (Trace)
- Tracing::write(Tracing::THREAT, Us, score);
+ if (DoTrace)
+ Trace::add(THREAT, Us, score);
return score;
}
// evaluate_passed_pawns() evaluates the passed pawns of the given color
- template<Color Us, bool Trace>
+ template<Color Us, bool DoTrace>
Score evaluate_passed_pawns(const Position& pos, const EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
int r = relative_rank(Us, s) - RANK_2;
int rr = r * (r - 1);
- // Base bonus based on rank
- Value mbonus = Value(17 * rr), ebonus = Value(7 * (rr + r + 1));
+ Value mbonus = Passed[MG][r], ebonus = Passed[EG][r];
if (rr)
{
Square blockSq = s + pawn_push(Us);
// Adjust bonus based on the king's proximity
- ebonus += distance(pos.king_square(Them), blockSq) * 5 * rr
- - distance(pos.king_square(Us ), blockSq) * 2 * rr;
+ ebonus += distance(pos.square<KING>(Them), blockSq) * 5 * rr
+ - distance(pos.square<KING>(Us ), blockSq) * 2 * rr;
// If blockSq is not the queening square then consider also a second push
if (relative_rank(Us, blockSq) != RANK_8)
- ebonus -= distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr;
+ ebonus -= distance(pos.square<KING>(Us), blockSq + pawn_push(Us)) * rr;
// If the pawn is free to advance, then increase the bonus
if (pos.empty(blockSq))
score += make_score(mbonus, ebonus);
}
- if (Trace)
- Tracing::write(Tracing::PASSED, Us, score * Weights[PassedPawns]);
+ if (DoTrace)
+ Trace::add(PASSED, Us, score * Weights[PassedPawns]);
// Add the scores to the middlegame and endgame eval
return score * Weights[PassedPawns];
behind |= (Us == WHITE ? behind >> 8 : behind << 8);
behind |= (Us == WHITE ? behind >> 16 : behind << 16);
- // Since SpaceMask[Us] is fully on our half of the board
+ // Since SpaceMask[Us] is fully on our half of the board...
assert(unsigned(safe >> (Us == WHITE ? 32 : 0)) == 0);
- // Count safe + (behind & safe) with a single popcount
+ // ...count safe + (behind & safe) with a single popcount
int bonus = popcount<Full>((Us == WHITE ? safe << 32 : safe >> 32) | (behind & safe));
int weight = pos.count<KNIGHT>(Us) + pos.count<BISHOP>(Us)
+ pos.count<KNIGHT>(Them) + pos.count<BISHOP>(Them);
return make_score(bonus * weight * weight, 0);
}
+} // namespace
- // do_evaluate() is the evaluation entry point, called directly from evaluate()
-
- template<bool Trace>
- Value do_evaluate(const Position& pos) {
-
- assert(!pos.checkers());
-
- EvalInfo ei;
- Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO };
-
- // Initialize score by reading the incrementally updated scores included
- // in the position object (material + piece square tables).
- // Score is computed from the point of view of white.
- score = pos.psq_score();
-
- // Probe the material hash table
- ei.mi = Material::probe(pos);
- score += ei.mi->imbalance();
-
- // 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);
- score += ei.pi->pawns_score() * Weights[PawnStructure];
+/// 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.
- // Initialize attack and king safety bitboards
- init_eval_info<WHITE>(pos, ei);
- init_eval_info<BLACK>(pos, ei);
+template<bool DoTrace>
+Value Eval::evaluate(const Position& pos) {
- ei.attackedBy[WHITE][ALL_PIECES] |= ei.attackedBy[WHITE][KING];
- ei.attackedBy[BLACK][ALL_PIECES] |= ei.attackedBy[BLACK][KING];
+ assert(!pos.checkers());
- // Do not include in mobility squares protected by enemy pawns or occupied by our pawns or king
- Bitboard mobilityArea[] = { ~(ei.attackedBy[BLACK][PAWN] | pos.pieces(WHITE, PAWN, KING)),
- ~(ei.attackedBy[WHITE][PAWN] | pos.pieces(BLACK, PAWN, KING)) };
+ EvalInfo ei;
+ Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO };
- // Evaluate pieces and mobility
- score += evaluate_pieces<KNIGHT, WHITE, Trace>(pos, ei, mobility, mobilityArea);
- score += (mobility[WHITE] - mobility[BLACK]) * Weights[Mobility];
+ // Initialize score by reading the incrementally updated scores included
+ // in the position object (material + piece square tables).
+ // Score is computed from the point of view of white.
+ score = pos.psq_score();
- // 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);
+ // Probe the material hash table
+ Material::Entry* me = Material::probe(pos);
+ score += me->imbalance();
- // Evaluate tactical threats, we need full attack information including king
- score += evaluate_threats<WHITE, Trace>(pos, ei)
- - evaluate_threats<BLACK, Trace>(pos, ei);
+ // If we have a specialized evaluation function for the current material
+ // configuration, call it and return.
+ if (me->specialized_eval_exists())
+ return me->evaluate(pos);
- // 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);
+ // Probe the pawn hash table
+ ei.pi = Pawns::probe(pos);
+ score += ei.pi->pawns_score() * Weights[PawnStructure];
- // If both sides have only pawns, score for potential unstoppable pawns
- if (!pos.non_pawn_material(WHITE) && !pos.non_pawn_material(BLACK))
- {
- Bitboard b;
- if ((b = ei.pi->passed_pawns(WHITE)) != 0)
- score += int(relative_rank(WHITE, frontmost_sq(WHITE, b))) * Unstoppable;
+ // Initialize attack and king safety bitboards
+ ei.attackedBy[WHITE][ALL_PIECES] = ei.attackedBy[BLACK][ALL_PIECES] = 0;
+ init_eval_info<WHITE>(pos, ei);
+ init_eval_info<BLACK>(pos, ei);
- if ((b = ei.pi->passed_pawns(BLACK)) != 0)
- score -= int(relative_rank(BLACK, frontmost_sq(BLACK, b))) * Unstoppable;
- }
+ // Pawns blocked or on ranks 2 and 3. Will be excluded from the mobility area
+ Bitboard blockedPawns[] = {
+ pos.pieces(WHITE, PAWN) & (shift_bb<DELTA_S>(pos.pieces()) | Rank2BB | Rank3BB),
+ pos.pieces(BLACK, PAWN) & (shift_bb<DELTA_N>(pos.pieces()) | Rank7BB | Rank6BB)
+ };
- // Evaluate space for both sides, only during opening
- if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= 11756)
- score += (evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei)) * Weights[Space];
+ // Do not include in mobility squares protected by enemy pawns, or occupied
+ // by our blocked pawns or king.
+ Bitboard mobilityArea[] = {
+ ~(ei.attackedBy[BLACK][PAWN] | blockedPawns[WHITE] | pos.square<KING>(WHITE)),
+ ~(ei.attackedBy[WHITE][PAWN] | blockedPawns[BLACK] | pos.square<KING>(BLACK))
+ };
- // Scale winning side if position is more drawish than it appears
- Color strongSide = eg_value(score) > VALUE_DRAW ? WHITE : BLACK;
- ScaleFactor sf = ei.mi->scale_factor(pos, strongSide);
+ // Evaluate pieces and mobility
+ score += evaluate_pieces<KNIGHT, WHITE, DoTrace>(pos, ei, mobility, mobilityArea);
+ score += (mobility[WHITE] - mobility[BLACK]) * Weights[Mobility];
- // If we don't already have an unusual scale factor, check for certain
- // types of endgames, and use a lower scale for those.
- if ( ei.mi->game_phase() < PHASE_MIDGAME
- && (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN))
- {
- if (pos.opposite_bishops())
- {
- // Endgame with opposite-colored bishops and no other pieces (ignoring pawns)
- // is almost a draw, in case of KBP vs KB is even more a draw.
- if ( pos.non_pawn_material(WHITE) == BishopValueMg
- && pos.non_pawn_material(BLACK) == BishopValueMg)
- sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(32) : ScaleFactor(8);
-
- // Endgame with opposite-colored bishops, but also other pieces. Still
- // a bit drawish, but not as drawish as with only the two bishops.
- else
- sf = ScaleFactor(50 * sf / SCALE_FACTOR_NORMAL);
- }
- // Endings where weaker side can place his king in front of the opponent's
- // pawns are drawish.
- else if ( abs(eg_value(score)) <= BishopValueEg
- && ei.pi->pawn_span(strongSide) <= 1
- && !pos.pawn_passed(~strongSide, pos.king_square(~strongSide)))
- sf = ei.pi->pawn_span(strongSide) ? ScaleFactor(56) : ScaleFactor(38);
- }
+ // Evaluate kings after all other pieces because we need complete attack
+ // information when computing the king safety evaluation.
+ score += evaluate_king<WHITE, DoTrace>(pos, ei)
+ - evaluate_king<BLACK, DoTrace>(pos, ei);
- // Interpolate between a middlegame and a (scaled by 'sf') endgame score
- Value v = mg_value(score) * int(ei.mi->game_phase())
- + eg_value(score) * int(PHASE_MIDGAME - ei.mi->game_phase()) * sf / SCALE_FACTOR_NORMAL;
+ // Evaluate tactical threats, we need full attack information including king
+ score += evaluate_threats<WHITE, DoTrace>(pos, ei)
+ - evaluate_threats<BLACK, DoTrace>(pos, ei);
- v /= int(PHASE_MIDGAME);
+ // Evaluate passed pawns, we need full attack information including king
+ score += evaluate_passed_pawns<WHITE, DoTrace>(pos, ei)
+ - evaluate_passed_pawns<BLACK, DoTrace>(pos, ei);
- // In case of tracing add all single evaluation terms for both white and black
- if (Trace)
- {
- Tracing::write(Tracing::MATERIAL, pos.psq_score());
- Tracing::write(Tracing::IMBALANCE, ei.mi->imbalance());
- Tracing::write(PAWN, ei.pi->pawns_score());
- Tracing::write(Tracing::MOBILITY, mobility[WHITE] * Weights[Mobility]
- , mobility[BLACK] * Weights[Mobility]);
- Tracing::write(Tracing::SPACE, evaluate_space<WHITE>(pos, ei) * Weights[Space]
- , evaluate_space<BLACK>(pos, ei) * Weights[Space]);
- Tracing::write(Tracing::TOTAL, score);
- }
+ // If both sides have only pawns, score for potential unstoppable pawns
+ if (!pos.non_pawn_material(WHITE) && !pos.non_pawn_material(BLACK))
+ {
+ Bitboard b;
+ if ((b = ei.pi->passed_pawns(WHITE)) != 0)
+ score += int(relative_rank(WHITE, frontmost_sq(WHITE, b))) * Unstoppable;
- return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo; // Side to move point of view
+ if ((b = ei.pi->passed_pawns(BLACK)) != 0)
+ score -= int(relative_rank(BLACK, frontmost_sq(BLACK, b))) * Unstoppable;
}
-
- // Tracing functions
-
- double Tracing::to_cp(Value v) { return double(v) / PawnValueEg; }
-
- void Tracing::write(int idx, Color c, Score s) { scores[c][idx] = s; }
-
- void Tracing::write(int idx, Score w, Score b) {
- scores[WHITE][idx] = w, scores[BLACK][idx] = b;
+ // Evaluate space for both sides, only during opening
+ if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= 11756)
+ score += (evaluate_space<WHITE>(pos, ei) - evaluate_space<BLACK>(pos, ei)) * Weights[Space];
+
+ // Scale winning side if position is more drawish than it appears
+ Color strongSide = eg_value(score) > VALUE_DRAW ? WHITE : BLACK;
+ ScaleFactor sf = me->scale_factor(pos, strongSide);
+
+ // If we don't already have an unusual scale factor, check for certain
+ // types of endgames, and use a lower scale for those.
+ if ( me->game_phase() < PHASE_MIDGAME
+ && (sf == SCALE_FACTOR_NORMAL || sf == SCALE_FACTOR_ONEPAWN))
+ {
+ if (pos.opposite_bishops())
+ {
+ // Endgame with opposite-colored bishops and no other pieces (ignoring pawns)
+ // is almost a draw, in case of KBP vs KB is even more a draw.
+ if ( pos.non_pawn_material(WHITE) == BishopValueMg
+ && pos.non_pawn_material(BLACK) == BishopValueMg)
+ sf = more_than_one(pos.pieces(PAWN)) ? ScaleFactor(32) : ScaleFactor(8);
+
+ // Endgame with opposite-colored bishops, but also other pieces. Still
+ // a bit drawish, but not as drawish as with only the two bishops.
+ else
+ sf = ScaleFactor(50 * sf / SCALE_FACTOR_NORMAL);
+ }
+ // Endings where weaker side can place his king in front of the opponent's
+ // pawns are drawish.
+ else if ( abs(eg_value(score)) <= BishopValueEg
+ && ei.pi->pawn_span(strongSide) <= 1
+ && !pos.pawn_passed(~strongSide, pos.square<KING>(~strongSide)))
+ sf = ei.pi->pawn_span(strongSide) ? ScaleFactor(56) : ScaleFactor(38);
}
- std::ostream& Tracing::operator<<(std::ostream& os, Term t) {
-
- double wScore[] = { to_cp(mg_value(scores[WHITE][t])), to_cp(eg_value(scores[WHITE][t])) };
- double bScore[] = { to_cp(mg_value(scores[BLACK][t])), to_cp(eg_value(scores[BLACK][t])) };
-
- if (t == MATERIAL || t == IMBALANCE || t == Term(PAWN) || t == TOTAL)
- os << " --- --- | --- --- | ";
- else
- os << std::setw(5) << wScore[MG] << " " << std::setw(5) << wScore[EG] << " | "
- << std::setw(5) << bScore[MG] << " " << std::setw(5) << bScore[EG] << " | ";
+ // Scale endgame by number of pawns
+ int p = pos.count<PAWN>(WHITE) + pos.count<PAWN>(BLACK);
+ int v_eg = 1 + abs(int(eg_value(score)));
+ sf = ScaleFactor(std::max(sf / 2, sf - 7 * SCALE_FACTOR_NORMAL * (14 - p) / v_eg));
+
+ // Interpolate between a middlegame and a (scaled by 'sf') endgame score
+ Value v = mg_value(score) * int(me->game_phase())
+ + eg_value(score) * int(PHASE_MIDGAME - me->game_phase()) * sf / SCALE_FACTOR_NORMAL;
+
+ v /= int(PHASE_MIDGAME);
+
+ // In case of tracing add all single evaluation terms
+ if (DoTrace)
+ {
+ Trace::add(MATERIAL, pos.psq_score());
+ Trace::add(IMBALANCE, me->imbalance());
+ Trace::add(PAWN, ei.pi->pawns_score());
+ Trace::add(MOBILITY, mobility[WHITE] * Weights[Mobility]
+ , mobility[BLACK] * Weights[Mobility]);
+ Trace::add(SPACE, evaluate_space<WHITE>(pos, ei) * Weights[Space]
+ , evaluate_space<BLACK>(pos, ei) * Weights[Space]);
+ Trace::add(TOTAL, score);
+ }
- os << std::setw(5) << wScore[MG] - bScore[MG] << " "
- << std::setw(5) << wScore[EG] - bScore[EG] << " \n";
+ return (pos.side_to_move() == WHITE ? v : -v) + Eval::Tempo; // Side to move point of view
+}
- return os;
- }
+// Explicit template instantiations
+template Value Eval::evaluate<true >(const Position&);
+template Value Eval::evaluate<false>(const Position&);
- std::string Tracing::do_trace(const Position& pos) {
-
- std::memset(scores, 0, sizeof(scores));
-
- 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::noshowpos << std::fixed << std::setprecision(2)
- << " Eval term | White | Black | Total \n"
- << " | MG EG | MG EG | MG EG \n"
- << "----------------+-------------+-------------+-------------\n"
- << " Material | " << Term(MATERIAL)
- << " Imbalance | " << Term(IMBALANCE)
- << " Pawns | " << Term(PAWN)
- << " Knights | " << Term(KNIGHT)
- << " Bishop | " << Term(BISHOP)
- << " Rooks | " << Term(ROOK)
- << " Queens | " << Term(QUEEN)
- << " Mobility | " << Term(MOBILITY)
- << " King safety | " << Term(KING)
- << " Threats | " << Term(THREAT)
- << " Passed pawns | " << Term(PASSED)
- << " Space | " << Term(SPACE)
- << "----------------+-------------+-------------+-------------\n"
- << " Total | " << Term(TOTAL);
-
- ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n";
-
- return ss.str();
- }
-} // namespace
+/// 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. Useful for debugging.
+std::string Eval::trace(const Position& pos) {
-namespace Eval {
+ std::memset(scores, 0, sizeof(scores));
- /// 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 v = evaluate<true>(pos);
+ v = pos.side_to_move() == WHITE ? v : -v; // White's point of view
- Value evaluate(const Position& pos) {
- return do_evaluate<false>(pos);
- }
+ std::stringstream ss;
+ ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2)
+ << " Eval term | White | Black | Total \n"
+ << " | MG EG | MG EG | MG EG \n"
+ << "----------------+-------------+-------------+-------------\n"
+ << " Material | " << Term(MATERIAL)
+ << " Imbalance | " << Term(IMBALANCE)
+ << " Pawns | " << Term(PAWN)
+ << " Knights | " << Term(KNIGHT)
+ << " Bishop | " << Term(BISHOP)
+ << " Rooks | " << Term(ROOK)
+ << " Queens | " << Term(QUEEN)
+ << " Mobility | " << Term(MOBILITY)
+ << " King safety | " << Term(KING)
+ << " Threats | " << Term(THREAT)
+ << " Passed pawns | " << Term(PASSED)
+ << " Space | " << Term(SPACE)
+ << "----------------+-------------+-------------+-------------\n"
+ << " Total | " << Term(TOTAL);
+ ss << "\nTotal Evaluation: " << to_cp(v) << " (white side)\n";
- /// 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);
- }
+ return ss.str();
+}
- /// init() computes evaluation weights, usually at startup
+/// init() computes evaluation weights, usually at startup
- void init() {
+void Eval::init() {
- const int MaxSlope = 8700;
- const int Peak = 1280000;
- int t = 0;
+ const int MaxSlope = 8700;
+ const int Peak = 1280000;
+ int t = 0;
- for (int i = 0; i < 400; ++i)
- {
- t = std::min(Peak, std::min(i * i * 27, t + MaxSlope));
- KingDanger[i] = make_score(t / 1000, 0) * Weights[KingSafety];
- }
+ for (int i = 0; i < 400; ++i)
+ {
+ t = std::min(Peak, std::min(i * i * 27, t + MaxSlope));
+ KingDanger[i] = make_score(t / 1000, 0) * Weights[KingSafety];
}
-
-} // namespace Eval
+}
projects / stockfish / blobdiff