X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=dd719554e18971081f4bd3648d7cbafdec268bc8;hp=c7fec9131e11ceeef0b1499c92b2ea1c012c0d83;hb=091aff044516fcd8700a8a194f9e9ffaabed8bb4;hpb=03cd049c6858f5d1c4b7e50f08d7ddc45e0a029e diff --git a/src/evaluate.cpp b/src/evaluate.cpp index c7fec913..dd719554 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -32,7 +32,7 @@ namespace { enum ExtendedPieceType { // Used for tracing - PST = 8, IMBALANCE, MOBILITY, THREAT, PASSED, UNSTOPPABLE, SPACE, TOTAL + PST = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL }; namespace Tracing { @@ -83,6 +83,8 @@ namespace { // king is on g8 and there's a white knight on g5, this knight adds // 2 to kingAdjacentZoneAttacksCount[BLACK]. int kingAdjacentZoneAttacksCount[COLOR_NB]; + + Bitboard pinnedPieces[COLOR_NB]; }; // Evaluation grain size, must be a power of 2 @@ -172,9 +174,11 @@ namespace { const Score RookOpenFile = make_score(43, 21); const Score RookSemiopenFile = make_score(19, 10); const Score BishopPawns = make_score( 8, 12); + const Score KnightPawns = make_score( 8, 4); const Score MinorBehindPawn = make_score(16, 0); const Score UndefendedMinor = make_score(25, 10); const Score TrappedRook = make_score(90, 0); + const Score Unstoppable = make_score( 0, 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 @@ -186,12 +190,8 @@ namespace { // based on how many squares inside this area are safe and available for // friendly minor pieces. const Bitboard SpaceMask[] = { - (1ULL << SQ_C2) | (1ULL << SQ_D2) | (1ULL << SQ_E2) | (1ULL << SQ_F2) | - (1ULL << SQ_C3) | (1ULL << SQ_D3) | (1ULL << SQ_E3) | (1ULL << SQ_F3) | - (1ULL << SQ_C4) | (1ULL << SQ_D4) | (1ULL << SQ_E4) | (1ULL << SQ_F4), - (1ULL << SQ_C7) | (1ULL << SQ_D7) | (1ULL << SQ_E7) | (1ULL << SQ_F7) | - (1ULL << SQ_C6) | (1ULL << SQ_D6) | (1ULL << SQ_E6) | (1ULL << SQ_F6) | - (1ULL << SQ_C5) | (1ULL << SQ_D5) | (1ULL << SQ_E5) | (1ULL << SQ_F5) + (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank2BB | Rank3BB | Rank4BB), + (FileCBB | FileDBB | FileEBB | FileFBB) & (Rank7BB | Rank6BB | Rank5BB) }; // King danger constants and variables. The king danger scores are taken @@ -203,12 +203,12 @@ namespace { const int KingAttackWeights[] = { 0, 0, 2, 2, 3, 5 }; // Bonuses for enemy's safe checks - const int QueenContactCheck = 6; - const int RookContactCheck = 4; - const int QueenCheck = 3; - const int RookCheck = 2; - const int BishopCheck = 1; - const int KnightCheck = 1; + const int QueenContactCheck = 24; + const int RookContactCheck = 16; + const int QueenCheck = 12; + const int RookCheck = 8; + const int BishopCheck = 2; + const int KnightCheck = 3; // KingExposed[Square] contains penalties based on the position of the // defending king, indexed by king's square (from white's point of view). @@ -229,16 +229,16 @@ namespace { // Function prototypes template - Value do_evaluate(const Position& pos, Value& margin); + Value do_evaluate(const Position& pos); template void init_eval_info(const Position& pos, EvalInfo& ei); template - Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility); + Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score* mobility); template - Score evaluate_king(const Position& pos, const EvalInfo& ei, Value margins[]); + Score evaluate_king(const Position& pos, const EvalInfo& ei); template Score evaluate_threats(const Position& pos, const EvalInfo& ei); @@ -249,7 +249,7 @@ namespace { template int evaluate_space(const Position& pos, const EvalInfo& ei); - Score evaluate_unstoppable_pawns(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); @@ -264,8 +264,8 @@ namespace Eval { /// values, an endgame score and a middle game score, and interpolates /// between them based on the remaining material. - Value evaluate(const Position& pos, Value& margin) { - return do_evaluate(pos, margin); + Value evaluate(const Position& pos) { + return do_evaluate(pos); } @@ -292,7 +292,7 @@ namespace Eval { const int MaxSlope = 30; const int Peak = 1280; - for (int t = 0, i = 1; i < 100; i++) + for (int t = 0, i = 1; i < 100; ++i) { t = std::min(Peak, std::min(int(0.4 * i * i), t + MaxSlope)); @@ -307,19 +307,14 @@ namespace Eval { namespace { template -Value do_evaluate(const Position& pos, Value& margin) { +Value do_evaluate(const Position& pos) { assert(!pos.checkers()); EvalInfo ei; - Value margins[COLOR_NB]; - Score score, mobilityWhite, mobilityBlack; + Score score, mobility[2] = { SCORE_ZERO, SCORE_ZERO }; Thread* th = pos.this_thread(); - // margins[] store the uncertainty estimation of position's evaluation - // that typically is used by the search for pruning decisions. - margins[WHITE] = margins[BLACK] = VALUE_ZERO; - // Initialize score by reading the incrementally updated scores included // in the position object (material + piece square tables) and adding // Tempo bonus. Score is computed from the point of view of white. @@ -332,10 +327,7 @@ Value do_evaluate(const Position& pos, Value& margin) { // If we have a specialized evaluation function for the current material // configuration, call it and return. if (ei.mi->specialized_eval_exists()) - { - margin = VALUE_ZERO; return ei.mi->evaluate(pos); - } // Probe the pawn hash table ei.pi = Pawns::probe(pos, th->pawnsTable); @@ -346,15 +338,15 @@ Value do_evaluate(const Position& pos, Value& margin) { init_eval_info(pos, ei); // Evaluate pieces and mobility - score += evaluate_pieces_of_color(pos, ei, mobilityWhite) - - evaluate_pieces_of_color(pos, ei, mobilityBlack); + score += evaluate_pieces_of_color(pos, ei, mobility) + - evaluate_pieces_of_color(pos, ei, mobility); - score += apply_weight(mobilityWhite - mobilityBlack, Weights[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(pos, ei, margins) - - evaluate_king(pos, ei, margins); + score += evaluate_king(pos, ei) + - evaluate_king(pos, ei); // Evaluate tactical threats, we need full attack information including king score += evaluate_threats(pos, ei) @@ -364,9 +356,10 @@ Value do_evaluate(const Position& pos, Value& margin) { score += evaluate_passed_pawns(pos, ei) - evaluate_passed_pawns(pos, ei); - // If one side has only a king, check whether exists any unstoppable passed pawn + // 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, ei); + score += evaluate_unstoppable_pawns(pos, WHITE, ei) + - evaluate_unstoppable_pawns(pos, BLACK, ei); // Evaluate space for both sides, only in middle-game. if (ei.mi->space_weight()) @@ -400,7 +393,6 @@ Value do_evaluate(const Position& pos, Value& margin) { sf = ScaleFactor(50); } - margin = margins[pos.side_to_move()]; Value v = interpolate(score, ei.mi->game_phase(), sf); // In case of tracing add all single evaluation contributions for both white and black @@ -409,14 +401,11 @@ Value do_evaluate(const Position& pos, Value& margin) { Tracing::add(PST, pos.psq_score()); Tracing::add(IMBALANCE, ei.mi->material_value()); Tracing::add(PAWN, ei.pi->pawns_value()); - Tracing::add(UNSTOPPABLE, evaluate_unstoppable_pawns(pos, ei)); Score w = ei.mi->space_weight() * evaluate_space(pos, ei); Score b = ei.mi->space_weight() * evaluate_space(pos, ei); Tracing::add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space])); Tracing::add(TOTAL, score); - Tracing::stream << "\nUncertainty margin: White: " << to_cp(margins[WHITE]) - << ", Black: " << to_cp(margins[BLACK]) - << "\nScaling: " << std::noshowpos + Tracing::stream << "\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" @@ -436,6 +425,8 @@ Value do_evaluate(const Position& pos, Value& margin) { const Color Them = (Us == WHITE ? BLACK : WHITE); const Square Down = (Us == WHITE ? DELTA_S : DELTA_N); + ei.pinnedPieces[Us] = pos.pinned_pieces(Us); + Bitboard b = ei.attackedBy[Them][KING] = pos.attacks_from(pos.king_square(Them)); ei.attackedBy[Us][PAWN] = ei.pi->pawn_attacks(Us); @@ -446,7 +437,8 @@ Value do_evaluate(const Position& pos, Value& margin) { b &= ei.attackedBy[Us][PAWN]; ei.kingAttackersCount[Us] = b ? popcount(b) / 2 : 0; ei.kingAdjacentZoneAttacksCount[Us] = ei.kingAttackersWeight[Us] = 0; - } else + } + else ei.kingRing[Them] = ei.kingAttackersCount[Us] = 0; } @@ -473,14 +465,15 @@ Value do_evaluate(const Position& pos, Value& margin) { else bonus += bonus / 2; } + return make_score(bonus, bonus); } - // evaluate_pieces<>() assigns bonuses and penalties to the pieces of a given color + // evaluate_pieces() assigns bonuses and penalties to the pieces of a given color template - 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; @@ -498,13 +491,16 @@ Value do_evaluate(const Position& pos, Value& margin) { : Piece == ROOK ? attacks_bb< ROOK>(s, pos.pieces() ^ pos.pieces(Us, ROOK, QUEEN)) : pos.attacks_from(s); + if (ei.pinnedPieces[Us] & s) + b &= LineBB[pos.king_square(Us)][s]; + ei.attackedBy[Us][Piece] |= b; if (b & ei.kingRing[Them]) { ei.kingAttackersCount[Us]++; ei.kingAttackersWeight[Us] += KingAttackWeights[Piece]; - Bitboard bb = (b & ei.attackedBy[Them][KING]); + Bitboard bb = b & ei.attackedBy[Them][KING]; if (bb) ei.kingAdjacentZoneAttacksCount[Us] += popcount(bb); } @@ -512,7 +508,7 @@ Value do_evaluate(const Position& pos, Value& margin) { int mob = Piece != QUEEN ? popcount(b & mobilityArea) : popcount(b & mobilityArea); - mobility += MobilityBonus[Piece][mob]; + mobility[Us] += MobilityBonus[Piece][mob]; // Decrease score if we are attacked by an enemy pawn. Remaining part // of threat evaluation must be done later when we have full attack info. @@ -530,6 +526,10 @@ Value do_evaluate(const Position& pos, Value& margin) { if (Piece == BISHOP) score -= BishopPawns * ei.pi->pawns_on_same_color_squares(Us, s); + // Penalty for knight when there are few enemy pawns + if (Piece == KNIGHT) + score -= KnightPawns * std::max(5 - pos.count(Them), 0); + if (Piece == BISHOP || Piece == KNIGHT) { // Bishop and knight outposts squares @@ -586,9 +586,9 @@ Value do_evaluate(const Position& pos, Value& margin) { const enum Piece P = make_piece(Us, PAWN); Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W); if (pos.piece_on(s + d) == P) - score -= !pos.is_empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4 - : pos.piece_on(s + d + d) == P ? TrappedBishopA1H1 * 2 - : TrappedBishopA1H1; + score -= !pos.empty(s + d + pawn_push(Us)) ? TrappedBishopA1H1 * 4 + : pos.piece_on(s + d + d) == P ? TrappedBishopA1H1 * 2 + : TrappedBishopA1H1; } } @@ -599,82 +599,37 @@ Value do_evaluate(const Position& pos, Value& margin) { } - // evaluate_threats<>() assigns bonuses according to the type of attacking piece - // and the type of attacked one. - - template - Score evaluate_threats(const Position& pos, const EvalInfo& ei) { - - const Color Them = (Us == WHITE ? BLACK : WHITE); - - Bitboard b, undefendedMinors, weakEnemies; - Score score = SCORE_ZERO; - - // Undefended minors get penalized even if not under attack - undefendedMinors = pos.pieces(Them, BISHOP, KNIGHT) - & ~ei.attackedBy[Them][ALL_PIECES]; - - if (undefendedMinors) - score += UndefendedMinor; - - // Enemy pieces not defended by a pawn and under our attack - weakEnemies = pos.pieces(Them) - & ~ei.attackedBy[Them][PAWN] - & ei.attackedBy[Us][ALL_PIECES]; - - // Add bonus according to type of attacked enemy piece and to the - // type of attacking piece, from knights to queens. Kings are not - // considered because are already handled in king evaluation. - if (weakEnemies) - for (PieceType pt1 = KNIGHT; pt1 < KING; pt1++) - { - b = ei.attackedBy[Us][pt1] & weakEnemies; - if (b) - for (PieceType pt2 = PAWN; pt2 < KING; pt2++) - if (b & pos.pieces(pt2)) - score += Threat[pt1][pt2]; - } - - if (Trace) - Tracing::scores[Us][THREAT] = score; - - return score; - } - - - // evaluate_pieces_of_color<>() assigns bonuses and penalties to all the + // evaluate_pieces_of_color() assigns bonuses and penalties to all the // pieces of a given color. template - Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score& mobility) { + Score evaluate_pieces_of_color(const Position& pos, EvalInfo& ei, Score* mobility) { const Color Them = (Us == WHITE ? BLACK : WHITE); - Score score = mobility = SCORE_ZERO; - // 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 += evaluate_pieces(pos, ei, mobility, mobilityArea); - score += evaluate_pieces(pos, ei, mobility, mobilityArea); - score += evaluate_pieces(pos, ei, mobility, mobilityArea); - score += evaluate_pieces(pos, ei, mobility, mobilityArea); + Score score = evaluate_pieces(pos, ei, mobility, mobilityArea) + + evaluate_pieces(pos, ei, mobility, mobilityArea) + + evaluate_pieces(pos, ei, mobility, mobilityArea) + + evaluate_pieces(pos, ei, mobility, mobilityArea); - // Sum up all attacked squares - 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]; + // 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::scores[Us][MOBILITY] = apply_weight(mobility, Weights[Mobility]); + Tracing::scores[Us][MOBILITY] = apply_weight(mobility[Us], Weights[Mobility]); return score; } - // evaluate_king<>() assigns bonuses and penalties to a king of a given color + // evaluate_king() assigns bonuses and penalties to a king of a given color template - Score evaluate_king(const Position& pos, const EvalInfo& ei, Value margins[]) { + Score evaluate_king(const Position& pos, const EvalInfo& ei) { const Color Them = (Us == WHITE ? BLACK : WHITE); @@ -685,15 +640,15 @@ Value do_evaluate(const Position& pos, Value& margin) { // King shelter and enemy pawns storm Score score = ei.pi->king_safety(pos, ksq); - // King safety. This is quite complicated, and is almost certainly far - // from optimally tuned. + // Main king safety evaluation if ( ei.kingAttackersCount[Them] >= 2 && ei.kingAdjacentZoneAttacksCount[Them]) { // Find the attacked squares around the king which has no defenders // apart from the king itself - undefended = ei.attackedBy[Them][ALL_PIECES] & ei.attackedBy[Us][KING]; - undefended &= ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT] + undefended = ei.attackedBy[Them][ALL_PIECES] + & ei.attackedBy[Us][KING] + & ~( ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK] | ei.attackedBy[Us][QUEEN]); @@ -702,7 +657,7 @@ Value do_evaluate(const Position& pos, Value& margin) { // number and types of the enemy's attacking pieces, the number of // attacked and undefended squares around our king, the square of the // king, and the quality of the pawn shelter. - attackUnits = std::min(25, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2) + attackUnits = std::min(20, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2) + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount(undefended)) + KingExposed[relative_square(Us, ksq)] - mg_value(score) / 32; @@ -769,12 +724,8 @@ Value do_evaluate(const Position& pos, Value& margin) { attackUnits = std::min(99, std::max(0, attackUnits)); // Finally, extract the king danger score from the KingDanger[] - // array and subtract the score from evaluation. Set also margins[] - // value that will be used for pruning because this value can sometimes - // be very big, and so capturing a single attacking piece can therefore - // result in a score change far bigger than the value of the captured piece. + // array and subtract the score from evaluation. score -= KingDanger[Us == Search::RootColor][attackUnits]; - margins[Us] += mg_value(KingDanger[Us == Search::RootColor][attackUnits]); } if (Trace) @@ -784,7 +735,50 @@ Value do_evaluate(const Position& pos, Value& margin) { } - // evaluate_passed_pawns<>() evaluates the passed pawns of the given color + // evaluate_threats() assigns bonuses according to the type of attacking piece + // and the type of attacked one. + + template + Score evaluate_threats(const Position& pos, const EvalInfo& ei) { + + const Color Them = (Us == WHITE ? BLACK : WHITE); + + Bitboard b, undefendedMinors, weakEnemies; + Score score = SCORE_ZERO; + + // Undefended minors get penalized even if not under attack + undefendedMinors = pos.pieces(Them, BISHOP, KNIGHT) + & ~ei.attackedBy[Them][ALL_PIECES]; + + if (undefendedMinors) + score += UndefendedMinor; + + // Enemy pieces not defended by a pawn and under our attack + weakEnemies = pos.pieces(Them) + & ~ei.attackedBy[Them][PAWN] + & ei.attackedBy[Us][ALL_PIECES]; + + // Add bonus according to type of attacked enemy piece and to the + // type of attacking piece, from knights to queens. Kings are not + // considered because are already handled in king evaluation. + if (weakEnemies) + for (PieceType pt1 = KNIGHT; pt1 < KING; ++pt1) + { + b = ei.attackedBy[Us][pt1] & weakEnemies; + if (b) + for (PieceType pt2 = PAWN; pt2 < KING; ++pt2) + if (b & pos.pieces(pt2)) + score += Threat[pt1][pt2]; + } + + if (Trace) + Tracing::scores[Us][THREAT] = score; + + return score; + } + + + // evaluate_passed_pawns() evaluates the passed pawns of the given color template Score evaluate_passed_pawns(const Position& pos, const EvalInfo& ei) { @@ -800,7 +794,7 @@ Value do_evaluate(const Position& pos, Value& margin) { { Square s = pop_lsb(&b); - assert(pos.pawn_is_passed(Us, s)); + assert(pos.pawn_passed(Us, s)); int r = int(relative_rank(Us, s) - RANK_2); int rr = r * (r - 1); @@ -814,15 +808,15 @@ Value do_evaluate(const Position& pos, Value& margin) { Square blockSq = s + pawn_push(Us); // Adjust bonus based on kings proximity - ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 5 * rr); - ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 2 * rr); + ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 5 * rr) + - Value(square_distance(pos.king_square(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 -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr); // If the pawn is free to advance, increase bonus - if (pos.is_empty(blockSq)) + if (pos.empty(blockSq)) { squaresToQueen = forward_bb(Us, s); @@ -876,9 +870,14 @@ Value do_evaluate(const Position& pos, Value& margin) { { if (pos.non_pawn_material(Them) <= KnightValueMg) ebonus += ebonus / 4; + else if (pos.pieces(Them, ROOK, QUEEN)) ebonus -= ebonus / 4; } + + if (pos.count(Us) < pos.count(Them)) + ebonus += ebonus / 4; + score += make_score(mbonus, ebonus); } @@ -891,164 +890,18 @@ Value do_evaluate(const Position& pos, Value& margin) { } - // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides, this is quite - // conservative and returns a winning score only when we are very sure that the pawn is winning. - - Score evaluate_unstoppable_pawns(const Position& pos, const EvalInfo& ei) { - - Bitboard b, b2, blockers, supporters, queeningPath, candidates; - Square s, blockSq, queeningSquare; - Color c, winnerSide, loserSide; - bool pathDefended, opposed; - int pliesToGo, movesToGo, oppMovesToGo, sacptg, blockersCount, minKingDist, kingptg, d; - int pliesToQueen[] = { 256, 256 }; - - // Step 1. Hunt for unstoppable passed pawns. If we find at least one, - // record how many plies are required for promotion. - for (c = WHITE; c <= BLACK; c++) - { - // Skip if other side has non-pawn pieces - if (pos.non_pawn_material(~c)) - continue; - - b = ei.pi->passed_pawns(c); - - while (b) - { - s = pop_lsb(&b); - queeningSquare = relative_square(c, file_of(s) | RANK_8); - queeningPath = forward_bb(c, s); - - // Compute plies to queening and check direct advancement - movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(c, s) == RANK_2); - oppMovesToGo = square_distance(pos.king_square(~c), queeningSquare) - int(c != pos.side_to_move()); - pathDefended = ((ei.attackedBy[c][ALL_PIECES] & queeningPath) == queeningPath); - - if (movesToGo >= oppMovesToGo && !pathDefended) - continue; - - // Opponent king cannot block because path is defended and position - // is not in check. So only friendly pieces can be blockers. - assert(!pos.checkers()); - assert((queeningPath & pos.pieces()) == (queeningPath & pos.pieces(c))); + // evaluate_unstoppable_pawns() scores the most advanced among the passed and + // candidate pawns. In case opponent has no pieces but pawns, this is somewhat + // related to the possibility pawns are unstoppable. - // Add moves needed to free the path from friendly pieces and retest condition - movesToGo += popcount(queeningPath & pos.pieces(c)); + Score evaluate_unstoppable_pawns(const Position& pos, Color us, const EvalInfo& ei) { - if (movesToGo >= oppMovesToGo && !pathDefended) - continue; - - pliesToGo = 2 * movesToGo - int(c == pos.side_to_move()); - pliesToQueen[c] = std::min(pliesToQueen[c], pliesToGo); - } - } + Bitboard b = ei.pi->passed_pawns(us) | ei.pi->candidate_pawns(us); - // Step 2. If either side cannot promote at least three plies before the other side then situation - // becomes too complex and we give up. Otherwise we determine the possibly "winning side" - if (abs(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3) + if (!b || pos.non_pawn_material(~us)) return SCORE_ZERO; - winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK); - loserSide = ~winnerSide; - - // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss? - b = candidates = pos.pieces(loserSide, PAWN); - - while (b) - { - s = pop_lsb(&b); - - // Compute plies from queening - queeningSquare = relative_square(loserSide, file_of(s) | RANK_8); - movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2); - pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move()); - - // Check if (without even considering any obstacles) we're too far away or doubled - if ( pliesToQueen[winnerSide] + 3 <= pliesToGo - || (forward_bb(loserSide, s) & pos.pieces(loserSide, PAWN))) - candidates ^= s; - } - - // If any candidate is already a passed pawn it _may_ promote in time. We give up. - if (candidates & ei.pi->passed_pawns(loserSide)) - return SCORE_ZERO; - - // Step 4. Check new passed pawn creation through king capturing and pawn sacrifices - b = candidates; - - while (b) - { - s = pop_lsb(&b); - sacptg = blockersCount = 0; - minKingDist = kingptg = 256; - - // Compute plies from queening - queeningSquare = relative_square(loserSide, file_of(s) | RANK_8); - movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2); - pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move()); - - // Generate list of blocking pawns and supporters - supporters = adjacent_files_bb(file_of(s)) & candidates; - opposed = forward_bb(loserSide, s) & pos.pieces(winnerSide, PAWN); - blockers = passed_pawn_mask(loserSide, s) & pos.pieces(winnerSide, PAWN); - - assert(blockers); - - // How many plies does it take to remove all the blocking pawns? - while (blockers) - { - blockSq = pop_lsb(&blockers); - movesToGo = 256; - - // Check pawns that can give support to overcome obstacle, for instance - // black pawns: a4, b4 white: b2 then pawn in b4 is giving support. - if (!opposed) - { - b2 = supporters & in_front_bb(winnerSide, rank_of(blockSq + pawn_push(winnerSide))); - - while (b2) // This while-loop could be replaced with LSB/MSB (depending on color) - { - d = square_distance(blockSq, pop_lsb(&b2)) - 2; - movesToGo = std::min(movesToGo, d); - } - } - - // Check pawns that can be sacrificed against the blocking pawn - b2 = pawn_attack_span(winnerSide, blockSq) & candidates & ~(1ULL << s); - - while (b2) // This while-loop could be replaced with LSB/MSB (depending on color) - { - d = square_distance(blockSq, pop_lsb(&b2)) - 2; - movesToGo = std::min(movesToGo, d); - } - - // If obstacle can be destroyed with an immediate pawn exchange / sacrifice, - // it's not a real obstacle and we have nothing to add to pliesToGo. - if (movesToGo <= 0) - continue; - - // Plies needed to sacrifice against all the blocking pawns - sacptg += movesToGo * 2; - blockersCount++; - - // Plies needed for the king to capture all the blocking pawns - d = square_distance(pos.king_square(loserSide), blockSq); - minKingDist = std::min(minKingDist, d); - kingptg = (minKingDist + blockersCount) * 2; - } - - // Check if pawn sacrifice plan _may_ save the day - if (pliesToQueen[winnerSide] + 3 > pliesToGo + sacptg) - return SCORE_ZERO; - - // Check if king capture plan _may_ save the day (contains some false positives) - if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg) - return SCORE_ZERO; - } - - // Winning pawn is unstoppable and will promote as first, return big score - Score score = make_score(0, (Value) 1280 - 32 * pliesToQueen[winnerSide]); - return winnerSide == WHITE ? score : -score; + return Unstoppable * int(relative_rank(us, frontmost_sq(us, b))); } @@ -1133,7 +986,7 @@ Value do_evaluate(const Position& pos, Value& margin) { Score bScore = scores[BLACK][idx]; switch (idx) { - case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL: + case PST: case IMBALANCE: case PAWN: case TOTAL: stream << std::setw(20) << name << " | --- --- | --- --- | " << std::setw(6) << to_cp(mg_value(wScore)) << " " << std::setw(6) << to_cp(eg_value(wScore)) << " \n"; @@ -1156,8 +1009,7 @@ Value do_evaluate(const Position& pos, Value& margin) { stream << std::showpoint << std::showpos << std::fixed << std::setprecision(2); std::memset(scores, 0, 2 * (TOTAL + 1) * sizeof(Score)); - Value margin; - do_evaluate(pos, margin); + do_evaluate(pos); std::string totals = stream.str(); stream.str(""); @@ -1177,7 +1029,6 @@ Value do_evaluate(const Position& pos, Value& margin) { row("King safety", KING); row("Threats", THREAT); row("Passed pawns", PASSED); - row("Unstoppable pawns", UNSTOPPABLE); row("Space", SPACE); stream << "---------------------+-------------+-------------+---------------\n";