X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fevaluate.cpp;h=7844deb6ae27290333531b91ae220986096f4009;hp=912c05fc8b394942e46a864235dd9c29dda5d8e0;hb=af750bd2ef919ba8aca8986c40f06cd58f0aef05;hpb=7a1ff6d8ff39bb9e6844d24467899d47e942486f diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 912c05fc..7844deb6 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 { @@ -175,6 +175,7 @@ namespace { 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 @@ -245,7 +246,7 @@ 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); @@ -288,7 +289,7 @@ 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)); @@ -360,9 +361,10 @@ 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()) @@ -405,7 +407,6 @@ 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])); @@ -810,8 +811,8 @@ 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) @@ -894,160 +895,18 @@ 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. + // 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. - Score evaluate_unstoppable_pawns(const Position& pos, const EvalInfo& ei) { + Score evaluate_unstoppable_pawns(const Position& pos, Color us, 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 }; + Bitboard b = ei.pi->passed_pawns(us) | ei.pi->candidate_pawns(us); - // 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))); - - // Add moves needed to free the path from friendly pieces and retest condition - movesToGo += popcount(queeningPath & pos.pieces(c)); - - if (movesToGo >= oppMovesToGo && !pathDefended) - continue; - - pliesToGo = 2 * movesToGo - int(c == pos.side_to_move()); - pliesToQueen[c] = std::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(pliesToQueen[WHITE] - pliesToQueen[BLACK]) < 3) - 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)) + if (!b || pos.non_pawn_material(~us)) 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))); - - if (b2) - { - d = square_distance(blockSq, backmost_sq(winnerSide, b2)) - 2; - movesToGo = std::min(movesToGo, d); - } - } - - // Check pawns that can be sacrificed against the blocking pawn - b2 = pawn_attack_span(winnerSide, blockSq) & candidates & ~SquareBB[s]; - - if (b2) - { - d = square_distance(blockSq, backmost_sq(winnerSide, 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 or king capture plan _may_ save the day - if (pliesToQueen[winnerSide] + 3 > pliesToGo + std::min(kingptg, sacptg)) - 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(WHITE, frontmost_sq(us, b))); } @@ -1132,7 +991,7 @@ 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"; @@ -1176,7 +1035,6 @@ 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";