X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=77821a3ad3dde342e5981638dab3862cf6680110;hp=649842dc87384f568b390e497649f5c62fba6195;hb=b1929960f9b73cb8fcc86fdbdf7a8d2d1de4fc53;hpb=05cfb00f26ca075ac972e320aaeabefe20599aea diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 649842dc..77821a3a 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -17,11 +17,6 @@ along with this program. If not, see . */ - -//// -//// Includes -//// - #include #include #include @@ -34,18 +29,14 @@ #include "thread.h" #include "ucioption.h" - -//// -//// Local definitions -//// - namespace { // Struct EvalInfo contains various information computed and collected // by the evaluation functions. struct EvalInfo { - // Pointer to pawn hash table entry + // Pointers to material and pawn hash table entries + MaterialInfo* mi; PawnInfo* pi; // attackedBy[color][piece type] is a bitboard representing all squares @@ -84,7 +75,7 @@ namespace { const int GrainSize = 8; // Evaluation weights, initialized from UCI options - enum { Mobility, PawnStructure, PassedPawns, Space, KingDangerUs, KingDangerThem }; + enum { Mobility, PassedPawns, Space, KingDangerUs, KingDangerThem }; Score Weights[6]; typedef Value V; @@ -97,7 +88,7 @@ namespace { // // Values modified by Joona Kiiski const Score WeightsInternal[] = { - S(248, 271), S(233, 201), S(252, 259), S(46, 0), S(247, 0), S(259, 0) + S(248, 271), S(252, 259), S(46, 0), S(247, 0), S(259, 0) }; // MobilityBonus[PieceType][attacked] contains mobility bonuses for middle and @@ -224,7 +215,7 @@ namespace { // TracedTerms[Color][PieceType || TracedType] contains a breakdown of the // evaluation terms, used when tracing. - Score TracedTerms[2][16]; + Score TracedScores[2][16]; std::stringstream TraceStream; enum TracedType { @@ -261,6 +252,8 @@ namespace { Value scale_by_game_phase(const Score& v, Phase ph, ScaleFactor sf); Score weight_option(const std::string& mgOpt, const std::string& egOpt, Score internalWeight); void init_safety(); + double to_cp(Value v); + void trace_add(int idx, Score term_w, Score term_b = SCORE_ZERO); } @@ -269,107 +262,88 @@ namespace { /// between them based on the remaining material. Value evaluate(const Position& pos, Value& margin) { - return CpuHasPOPCNT ? do_evaluate(pos, margin) - : do_evaluate(pos, margin); + return CpuHasPOPCNT ? do_evaluate(pos, margin) + : do_evaluate(pos, margin); } namespace { -double to_cp(Value v) { return double(v) / double(PawnValueMidgame); } - -void trace_add(int idx, Score term_w, Score term_b = Score(0)) { - - TracedTerms[WHITE][idx] = term_w; - TracedTerms[BLACK][idx] = term_b; -} - template Value do_evaluate(const Position& pos, Value& margin) { EvalInfo ei; Value margins[2]; - Score mobilityWhite, mobilityBlack; + Score score, mobilityWhite, mobilityBlack; assert(pos.is_ok()); assert(pos.thread() >= 0 && pos.thread() < MAX_THREADS); - assert(!pos.is_check()); + assert(!pos.in_check()); - // Initialize value by reading the incrementally updated scores included + // Initialize score by reading the incrementally updated scores included // in the position object (material + piece square tables). - Score bonus = pos.value(); + score = pos.value(); // 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; // Probe the material hash table - MaterialInfo* mi = Threads[pos.thread()].materialTable.get_material_info(pos); - bonus += mi->material_value(); + ei.mi = Threads[pos.thread()].materialTable.get_material_info(pos); + score += ei.mi->material_value(); // If we have a specialized evaluation function for the current material // configuration, call it and return. - if (mi->specialized_eval_exists()) + if (ei.mi->specialized_eval_exists()) { margin = VALUE_ZERO; - return mi->evaluate(pos); + return ei.mi->evaluate(pos); } // Probe the pawn hash table ei.pi = Threads[pos.thread()].pawnTable.get_pawn_info(pos); - bonus += apply_weight(ei.pi->pawns_value(), Weights[PawnStructure]); + score += ei.pi->pawns_value(); // Initialize attack and king safety bitboards init_eval_info(pos, ei); init_eval_info(pos, ei); // Evaluate pieces and mobility - bonus += evaluate_pieces_of_color(pos, ei, mobilityWhite) + score += evaluate_pieces_of_color(pos, ei, mobilityWhite) - evaluate_pieces_of_color(pos, ei, mobilityBlack); - bonus += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]); + score += apply_weight(mobilityWhite - mobilityBlack, Weights[Mobility]); // Evaluate kings after all other pieces because we need complete attack // information when computing the king safety evaluation. - bonus += evaluate_king(pos, ei, margins) + score += evaluate_king(pos, ei, margins) - evaluate_king(pos, ei, margins); // Evaluate tactical threats, we need full attack information including king - bonus += evaluate_threats(pos, ei) + score += evaluate_threats(pos, ei) - evaluate_threats(pos, ei); // Evaluate passed pawns, we need full attack information including king - bonus += evaluate_passed_pawns(pos, ei) + 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 (!pos.non_pawn_material(WHITE) || !pos.non_pawn_material(BLACK)) - { - bonus += evaluate_unstoppable_pawns(pos, ei); - - if (Trace) - trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns(pos, ei)); - } + score += evaluate_unstoppable_pawns(pos, ei); // Evaluate space for both sides, only in middle-game. - if (mi->space_weight()) + if (ei.mi->space_weight()) { - int s_w = evaluate_space(pos, ei); - int s_b = evaluate_space(pos, ei); - bonus += apply_weight(make_score((s_w - s_b) * mi->space_weight(), 0), Weights[Space]); - - if (Trace) - trace_add(SPACE, apply_weight(make_score(s_w * mi->space_weight(), make_score(0, 0)), Weights[Space]), - apply_weight(make_score(s_b * mi->space_weight(), make_score(0, 0)), Weights[Space])); + int s = evaluate_space(pos, ei) - evaluate_space(pos, ei); + score += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]); } // Scale winning side if position is more drawish that what it appears - ScaleFactor sf = eg_value(bonus) > VALUE_DRAW ? mi->scale_factor(pos, WHITE) - : mi->scale_factor(pos, BLACK); - Phase phase = mi->game_phase(); + 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 ( phase < PHASE_MIDGAME + if ( ei.mi->game_phase() < PHASE_MIDGAME && pos.opposite_colored_bishops() && sf == SCALE_FACTOR_NORMAL) { @@ -390,22 +364,27 @@ Value do_evaluate(const Position& pos, Value& margin) { // Interpolate between the middle game and the endgame score margin = margins[pos.side_to_move()]; - Value v = scale_by_game_phase(bonus, phase, sf); + Value v = scale_by_game_phase(score, ei.mi->game_phase(), sf); + // In case of tracing add all single evaluation contributions for both white and black if (Trace) { trace_add(PST, pos.value()); - trace_add(IMBALANCE, mi->material_value()); - trace_add(PAWN, apply_weight(ei.pi->pawns_value(), Weights[PawnStructure])); + trace_add(IMBALANCE, ei.mi->material_value()); + trace_add(PAWN, ei.pi->pawns_value()); trace_add(MOBILITY, apply_weight(mobilityWhite, Weights[Mobility]), apply_weight(mobilityBlack, Weights[Mobility])); trace_add(THREAT, evaluate_threats(pos, ei), evaluate_threats(pos, ei)); trace_add(PASSED, evaluate_passed_pawns(pos, ei), evaluate_passed_pawns(pos, ei)); - trace_add(TOTAL, bonus); + trace_add(UNSTOPPABLE, evaluate_unstoppable_pawns(pos, ei)); + Score w = make_score(ei.mi->space_weight() * evaluate_space(pos, ei), 0); + Score b = make_score(ei.mi->space_weight() * evaluate_space(pos, ei), 0); + trace_add(SPACE, apply_weight(w, Weights[Space]), apply_weight(b, Weights[Space])); + trace_add(TOTAL, score); TraceStream << "\nUncertainty margin: White: " << to_cp(margins[WHITE]) << ", Black: " << to_cp(margins[BLACK]) << "\nScaling: " << std::noshowpos - << std::setw(6) << 100.0 * phase/128.0 << "% MG, " - << std::setw(6) << 100.0 * (1.0 - phase/128.0) << "% * " + << 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); } @@ -426,7 +405,6 @@ void read_evaluation_uci_options(Color us) { const int kingDangerThem = (us == WHITE ? KingDangerThem : KingDangerUs); 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[kingDangerUs] = weight_option("Cowardice", "Cowardice", WeightsInternal[KingDangerUs]); @@ -503,7 +481,7 @@ namespace { Square s, ksq; int mob; File f; - Score bonus = SCORE_ZERO; + Score score = SCORE_ZERO; const BitCountType Full = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64 : CNT32; const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15; @@ -546,18 +524,18 @@ namespace { // 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. if (bit_is_set(ei.attackedBy[Them][PAWN], s)) - bonus -= ThreatedByPawnPenalty[Piece]; + score -= ThreatedByPawnPenalty[Piece]; // Bishop and knight outposts squares if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Us)) - bonus += evaluate_outposts(pos, ei, s); + score += evaluate_outposts(pos, ei, s); // Queen or rook on 7th rank if ( (Piece == ROOK || Piece == QUEEN) && relative_rank(Us, s) == RANK_7 && relative_rank(Us, pos.king_square(Them)) == RANK_8) { - bonus += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus); + score += (Piece == ROOK ? RookOn7thBonus : QueenOn7thBonus); } // Special extra evaluation for bishops @@ -572,11 +550,11 @@ namespace { if (pos.piece_on(s + d) == make_piece(Us, PAWN)) { if (!pos.square_is_empty(s + d + pawn_push(Us))) - bonus -= 2*TrappedBishopA1H1Penalty; + score -= 2*TrappedBishopA1H1Penalty; else if (pos.piece_on(s + 2*d) == make_piece(Us, PAWN)) - bonus -= TrappedBishopA1H1Penalty; + score -= TrappedBishopA1H1Penalty; else - bonus -= TrappedBishopA1H1Penalty / 2; + score -= TrappedBishopA1H1Penalty / 2; } } } @@ -589,9 +567,9 @@ namespace { if (ei.pi->file_is_half_open(Us, f)) { if (ei.pi->file_is_half_open(Them, f)) - bonus += RookOpenFileBonus; + score += RookOpenFileBonus; else - bonus += RookHalfOpenFileBonus; + score += RookHalfOpenFileBonus; } // Penalize rooks which are trapped inside a king. Penalize more if @@ -607,7 +585,7 @@ namespace { { // Is there a half-open file between the king and the edge of the board? if (!ei.pi->has_open_file_to_right(Us, square_file(ksq))) - bonus -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2 + score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2 : (TrappedRookPenalty - mob * 16), 0); } else if ( square_file(ksq) <= FILE_D @@ -616,16 +594,16 @@ namespace { { // Is there a half-open file between the king and the edge of the board? if (!ei.pi->has_open_file_to_left(Us, square_file(ksq))) - bonus -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2 + score -= make_score(pos.can_castle(Us) ? (TrappedRookPenalty - mob * 16) / 2 : (TrappedRookPenalty - mob * 16), 0); } } } if (Trace) - TracedTerms[Us][Piece] = bonus; + TracedScores[Us][Piece] = score; - return bonus; + return score; } @@ -638,7 +616,7 @@ namespace { const Color Them = (Us == WHITE ? BLACK : WHITE); Bitboard b; - Score bonus = SCORE_ZERO; + Score score = SCORE_ZERO; // Enemy pieces not defended by a pawn and under our attack Bitboard weakEnemies = pos.pieces_of_color(Them) @@ -656,9 +634,9 @@ namespace { if (b) for (PieceType pt2 = PAWN; pt2 < KING; pt2++) if (b & pos.pieces(pt2)) - bonus += ThreatBonus[pt1][pt2]; + score += ThreatBonus[pt1][pt2]; } - return bonus; + return score; } @@ -670,21 +648,21 @@ namespace { const Color Them = (Us == WHITE ? BLACK : WHITE); - Score bonus = mobility = SCORE_ZERO; + 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_of_color(Us)); - bonus += evaluate_pieces(pos, ei, mobility, mobilityArea); - bonus += evaluate_pieces(pos, ei, mobility, mobilityArea); - bonus += evaluate_pieces(pos, ei, mobility, mobilityArea); - bonus += 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 += evaluate_pieces(pos, ei, mobility, mobilityArea); // Sum up all attacked squares ei.attackedBy[Us][0] = ei.attackedBy[Us][PAWN] | ei.attackedBy[Us][KNIGHT] | ei.attackedBy[Us][BISHOP] | ei.attackedBy[Us][ROOK] | ei.attackedBy[Us][QUEEN] | ei.attackedBy[Us][KING]; - return bonus; + return score; } @@ -701,7 +679,7 @@ namespace { const Square ksq = pos.king_square(Us); // King shelter - Score bonus = ei.pi->king_shelter(pos, ksq); + Score score = ei.pi->king_shelter(pos, ksq); // King safety. This is quite complicated, and is almost certainly far // from optimally tuned. @@ -791,14 +769,14 @@ namespace { // 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. - bonus -= KingDangerTable[Us][attackUnits]; + score -= KingDangerTable[Us][attackUnits]; margins[Us] += mg_value(KingDangerTable[Us][attackUnits]); } if (Trace) - TracedTerms[Us][KING] = bonus; + TracedScores[Us][KING] = score; - return bonus; + return score; } @@ -809,9 +787,10 @@ namespace { const Color Them = (Us == WHITE ? BLACK : WHITE); - Score bonus = SCORE_ZERO; - Bitboard squaresToQueen, defendedSquares, unsafeSquares, supportingPawns; - Bitboard b = ei.pi->passed_pawns(Us); + Bitboard b, squaresToQueen, defendedSquares, unsafeSquares, supportingPawns; + Score score = SCORE_ZERO; + + b = ei.pi->passed_pawns(Us); if (!b) return SCORE_ZERO; @@ -833,9 +812,12 @@ namespace { Square blockSq = s + pawn_push(Us); // Adjust bonus based on kings proximity - ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 3 * rr); - ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr); ebonus += Value(square_distance(pos.king_square(Them), blockSq) * 6 * rr); + ebonus -= Value(square_distance(pos.king_square(Us), blockSq) * 3 * rr); + + // If blockSq is not the queening square then consider also a second push + if (square_rank(blockSq) != (Us == WHITE ? RANK_8 : RANK_1)) + ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr); // If the pawn is free to advance, increase bonus if (pos.square_is_empty(blockSq)) @@ -891,174 +873,176 @@ namespace { else if (pos.pieces(ROOK, QUEEN, Them)) ebonus -= ebonus / 4; } - bonus += make_score(mbonus, ebonus); + score += make_score(mbonus, ebonus); } while (b); // Add the scores to the middle game and endgame eval - return apply_weight(bonus, Weights[PassedPawns]); + return apply_weight(score, Weights[PassedPawns]); } - // evaluate_unstoppable_pawns() evaluates the unstoppable passed pawns for both sides + + // 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. + template Score evaluate_unstoppable_pawns(const Position& pos, EvalInfo& ei) { const BitCountType Max15 = HasPopCnt ? CNT_POPCNT : CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15; - // Step 1. Hunt for unstoppable pawns. If we find at least one, record how many plies - // are required for promotion - int pliesToGo[2] = {256, 256}; + 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 }; - for (Color c = WHITE; c <= BLACK; c++) + // 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(opposite_color(c))) continue; - Bitboard b = ei.pi->passed_pawns(c); + b = ei.pi->passed_pawns(c); while (b) { - Square s = pop_1st_bit(&b); - Square queeningSquare = relative_square(c, make_square(square_file(s), RANK_8)); + s = pop_1st_bit(&b); + queeningSquare = relative_square(c, make_square(square_file(s), RANK_8)); + queeningPath = squares_in_front_of(c, s); - int mtg = RANK_8 - relative_rank(c, s) - int(relative_rank(c, s) == RANK_2); - int oppmtg = square_distance(pos.king_square(opposite_color(c)), queeningSquare) - int(c != pos.side_to_move()); - bool pathDefended = ((ei.attackedBy[c][0] & squares_in_front_of(c, s)) == squares_in_front_of(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(opposite_color(c)), queeningSquare) - int(c != pos.side_to_move()); + pathDefended = ((ei.attackedBy[c][0] & queeningPath) == queeningPath); - if (mtg >= oppmtg && !pathDefended) + if (movesToGo >= oppMovesToGo && !pathDefended) continue; - int blockerCount = count_1s(squares_in_front_of(c, s) & pos.occupied_squares()); - mtg += blockerCount; + // Opponent king cannot block because path is defended and position + // is not in check. So only friendly pieces can be blockers. + assert(!pos.in_check()); + assert(queeningPath & pos.occupied_squares() == queeningPath & pos.pieces_of_color(c)); - if (mtg >= oppmtg && !pathDefended) - continue; + // Add moves needed to free the path from friendly pieces and retest condition + movesToGo += count_1s(queeningPath & pos.pieces_of_color(c)); - int ptg = 2 * mtg - int(c == pos.side_to_move()); + if (movesToGo >= oppMovesToGo && !pathDefended) + continue; - if (ptg < pliesToGo[c]) - pliesToGo[c] = ptg; + pliesToGo = 2 * movesToGo - int(c == pos.side_to_move()); + pliesToQueen[c] = Min(pliesToQueen[c], pliesToGo); } } - // 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(pliesToGo[WHITE] - pliesToGo[BLACK]) < 3) - return make_score(0, 0); + // 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) + return SCORE_ZERO; - Color winnerSide = (pliesToGo[WHITE] < pliesToGo[BLACK] ? WHITE : BLACK); - Color loserSide = opposite_color(winnerSide); + winnerSide = (pliesToQueen[WHITE] < pliesToQueen[BLACK] ? WHITE : BLACK); + loserSide = opposite_color(winnerSide); // Step 3. Can the losing side possibly create a new passed pawn and thus prevent the loss? - // We collect the potential candidates in potentialBB. - Bitboard pawnBB = pos.pieces(PAWN, loserSide); - Bitboard potentialBB = pawnBB; - const Bitboard passedBB = ei.pi->passed_pawns(loserSide); + b = candidates = pos.pieces(PAWN, loserSide); - while(pawnBB) + while (b) { - Square psq = pop_1st_bit(&pawnBB); - - // Check direct advancement - int mtg = RANK_8 - relative_rank(loserSide, psq) - int(relative_rank(loserSide, psq) == RANK_2); - int ptg = 2 * mtg - int(loserSide == pos.side_to_move()); - - // Check if (without even considering any obstacles) we're too far away - if (pliesToGo[winnerSide] + 3 <= ptg) - { - clear_bit(&potentialBB, psq); - continue; - } + s = pop_1st_bit(&b); - // If this is passed pawn, then it _may_ promote in time. We give up. - if (bit_is_set(passedBB, psq)) - return make_score(0, 0); + // Compute plies from queening + queeningSquare = relative_square(loserSide, make_square(square_file(s), RANK_8)); + movesToGo = rank_distance(s, queeningSquare) - int(relative_rank(loserSide, s) == RANK_2); + pliesToGo = 2 * movesToGo - int(loserSide == pos.side_to_move()); - // Doubled pawn is worthless - if (squares_in_front_of(loserSide, psq) & (pos.pieces(PAWN, loserSide))) - { - clear_bit(&potentialBB, psq); - continue; - } + // Check if (without even considering any obstacles) we're too far away or doubled + if ( pliesToQueen[winnerSide] + 3 <= pliesToGo + || (squares_in_front_of(loserSide, s) & pos.pieces(PAWN, loserSide))) + clear_bit(&candidates, s); } - // Step 4. Check new passed pawn creation through king capturing and sacrifises - pawnBB = potentialBB; + // 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(pawnBB) + while (b) { - Square psq = pop_1st_bit(&pawnBB); + s = pop_1st_bit(&b); + sacptg = blockersCount = 0; + minKingDist = kingptg = 256; - int mtg = RANK_8 - relative_rank(loserSide, psq) - int(relative_rank(loserSide, psq) == RANK_2); - int ptg = 2 * mtg - int(loserSide == pos.side_to_move()); + // Compute plies from queening + queeningSquare = relative_square(loserSide, make_square(square_file(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 obstacles - Bitboard obsBB = passed_pawn_mask(loserSide, psq) & pos.pieces(PAWN, winnerSide); - const bool pawnIsOpposed = squares_in_front_of(loserSide, psq) & obsBB; - assert(obsBB); + // Generate list of blocking pawns and supporters + supporters = neighboring_files_bb(s) & candidates; + opposed = squares_in_front_of(loserSide, s) & pos.pieces(PAWN, winnerSide); + blockers = passed_pawn_mask(loserSide, s) & pos.pieces(PAWN, winnerSide); - // How many plies does it take to remove all the obstacles? - int sacptg = 0; - int realObsCount = 0; - int minKingDist = 256; + assert(blockers); - while(obsBB) + // How many plies does it take to remove all the blocking pawns? + while (blockers) { - Square obSq = pop_1st_bit(&obsBB); - int minMoves = 256; + blockSq = pop_1st_bit(&blockers); + movesToGo = 256; - // Check pawns that can give support to overcome obstacle (Eg. wp: a4,b4 bp: b2. b4 is giving support) - if (!pawnIsOpposed && square_file(psq) != square_file(obSq)) + // 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) { - Bitboard supBB = in_front_bb(winnerSide, Square(obSq + (winnerSide == WHITE ? 8 : -8))) - & neighboring_files_bb(psq) & potentialBB; + b2 = supporters & in_front_bb(winnerSide, blockSq + pawn_push(winnerSide)); - while(supBB) // This while-loop could be replaced with supSq = LSB/MSB(supBB) (depending on color) + while (b2) // This while-loop could be replaced with LSB/MSB (depending on color) { - Square supSq = pop_1st_bit(&supBB); - int dist = square_distance(obSq, supSq); - minMoves = Min(minMoves, dist - 2); + d = square_distance(blockSq, pop_1st_bit(&b2)) - 2; + movesToGo = Min(movesToGo, d); } - } - // Check pawns that can be sacrifised - Bitboard sacBB = passed_pawn_mask(winnerSide, obSq) & neighboring_files_bb(obSq) & potentialBB & ~(1ULL << psq); + // Check pawns that can be sacrificed against the blocking pawn + b2 = attack_span_mask(winnerSide, blockSq) & candidates & ~(1ULL << s); - while(sacBB) // This while-loop could be replaced with sacSq = LSB/MSB(sacBB) (depending on color) + while (b2) // This while-loop could be replaced with LSB/MSB (depending on color) { - Square sacSq = pop_1st_bit(&sacBB); - int dist = square_distance(obSq, sacSq); - minMoves = Min(minMoves, dist - 2); + d = square_distance(blockSq, pop_1st_bit(&b2)) - 2; + movesToGo = Min(movesToGo, d); } - // If obstacle can be destroyed with immediate pawn sacrifise, it's not real obstacle - if (minMoves <= 0) + // 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; - // Pawn sac calculations - sacptg += minMoves * 2; + // Plies needed to sacrifice against all the blocking pawns + sacptg += movesToGo * 2; + blockersCount++; - // King capture calc - realObsCount++; - int kingDist = square_distance(pos.king_square(loserSide), obSq); - minKingDist = Min(minKingDist, kingDist); + // Plies needed for the king to capture all the blocking pawns + d = square_distance(pos.king_square(loserSide), blockSq); + minKingDist = Min(minKingDist, d); + kingptg = (minKingDist + blockersCount) * 2; } - // Check if pawn sac plan _may_ save the day - if (pliesToGo[winnerSide] + 3 > ptg + sacptg) - return make_score(0, 0); + // 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) - int kingptg = (minKingDist + realObsCount) * 2; - if (pliesToGo[winnerSide] + 3 > ptg + kingptg) - return make_score(0, 0); + if (pliesToQueen[winnerSide] + 3 > pliesToGo + kingptg) + return SCORE_ZERO; } - // Step 5. Assign bonus - const int Sign[2] = {1, -1}; - return Sign[winnerSide] * make_score(0, (Value) 0x500 - 0x20 * pliesToGo[winnerSide]); + // Winning pawn is unstoppable and will promote as first, return big score + Score score = make_score(0, (Value) 0x500 - 0x20 * pliesToQueen[winnerSide]); + return winnerSide == WHITE ? score : -score; } @@ -1094,8 +1078,8 @@ namespace { // apply_weight() applies an evaluation weight to a value trying to prevent overflow inline Score apply_weight(Score v, Score w) { - return make_score((int(mg_value(v)) * mg_value(w)) / 0x100, - (int(eg_value(v)) * eg_value(w)) / 0x100); + return make_score((int(mg_value(v)) * mg_value(w)) / 0x100, + (int(eg_value(v)) * eg_value(w)) / 0x100); } @@ -1154,29 +1138,40 @@ namespace { } + // A couple of little helpers used by tracing code, to_cp() converts a value to + // a double in centipawns scale, trace_add() stores white and black scores. + + double to_cp(Value v) { return double(v) / double(PawnValueMidgame); } + + void trace_add(int idx, Score wScore, Score bScore) { + + TracedScores[WHITE][idx] = wScore; + TracedScores[BLACK][idx] = bScore; + } + // trace_row() is an helper function used by tracing code to register the // values of a single evaluation term. void trace_row(const char *name, int idx) { - Score term_w = TracedTerms[WHITE][idx]; - Score term_b = TracedTerms[BLACK][idx]; + Score wScore = TracedScores[WHITE][idx]; + Score bScore = TracedScores[BLACK][idx]; switch (idx) { case PST: case IMBALANCE: case PAWN: case UNSTOPPABLE: case TOTAL: TraceStream << std::setw(20) << name << " | --- --- | --- --- | " - << std::setw(6) << to_cp(mg_value(term_w)) << " " - << std::setw(6) << to_cp(eg_value(term_w)) << " \n"; + << std::setw(6) << to_cp(mg_value(wScore)) << " " + << std::setw(6) << to_cp(eg_value(wScore)) << " \n"; break; default: TraceStream << std::setw(20) << name << " | " << std::noshowpos - << std::setw(5) << to_cp(mg_value(term_w)) << " " - << std::setw(5) << to_cp(eg_value(term_w)) << " | " - << std::setw(5) << to_cp(mg_value(term_b)) << " " - << std::setw(5) << to_cp(eg_value(term_b)) << " | " + << std::setw(5) << to_cp(mg_value(wScore)) << " " + << 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(term_w - term_b)) << " " - << std::setw(6) << to_cp(eg_value(term_w - term_b)) << " \n"; + << std::setw(6) << to_cp(mg_value(wScore - bScore)) << " " + << std::setw(6) << to_cp(eg_value(wScore - bScore)) << " \n"; } } } @@ -1193,7 +1188,7 @@ std::string trace_evaluate(const Position& pos) { TraceStream.str(""); TraceStream << std::showpoint << std::showpos << std::fixed << std::setprecision(2); - memset(TracedTerms, 0, 2 * 16 * sizeof(Score)); + memset(TracedScores, 0, 2 * 16 * sizeof(Score)); do_evaluate(pos, margin);