From e236a0c6521c9d0c07e2fa9b392d2c10e009c86a Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Tue, 6 Jan 2009 15:49:33 +0100 Subject: [PATCH] Space inflate evaluate_passed_pawns() No functional change. Signed-off-by: Marco Costalba --- src/evaluate.cpp | 274 ++++++++++++++++++++++++----------------------- 1 file changed, 142 insertions(+), 132 deletions(-) diff --git a/src/evaluate.cpp b/src/evaluate.cpp index d261f448..6a6f9873 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -905,148 +905,158 @@ namespace { // evaluate_passed_pawns() evaluates the passed pawns for both sides. void evaluate_passed_pawns(const Position &pos, EvalInfo &ei) { + bool hasUnstoppable[2] = {false, false}; int movesToGo[2] = {100, 100}; - for(Color us = WHITE; us <= BLACK; us++) { - Color them = opposite_color(us); - Square ourKingSq = pos.king_square(us); - Square theirKingSq = pos.king_square(them); - Bitboard b = ei.pi->passed_pawns() & pos.pawns(us), b2, b3, b4; + for (Color us = WHITE; us <= BLACK; us++) + { + Color them = opposite_color(us); + Square ourKingSq = pos.king_square(us); + Square theirKingSq = pos.king_square(them); + Bitboard b = ei.pi->passed_pawns() & pos.pawns(us), b2, b3, b4; - while(b) { - Square s = pop_1st_bit(&b); - assert(pos.piece_on(s) == pawn_of_color(us)); - assert(pos.pawn_is_passed(us, s)); - - int r = int(relative_rank(us, s) - RANK_2); - int tr = Max(0, r * (r-1)); - Square blockSq = s + pawn_push(us); - - // Base bonus based on rank: - Value mbonus = Value(20 * tr); - Value ebonus = Value(10 + r * r * 10); - - // Adjust bonus based on king proximity: - ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr); - ebonus -= - Value(square_distance(ourKingSq, blockSq + pawn_push(us)) * 1 * tr); - ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr); - - // If the pawn is free to advance, increase bonus: - if(pos.square_is_empty(blockSq)) { - - b2 = squares_in_front_of(us, s); - b3 = b2 & ei.attacked_by(them); - b4 = b2 & ei.attacked_by(us); - - // If there is an enemy rook or queen attacking the pawn from behind, - // add all X-ray attacks by the rook or queen. - if(bit_is_set(ei.attacked_by(them,ROOK)|ei.attacked_by(them,QUEEN),s) - && squares_behind(us, s) & pos.rooks_and_queens(them)) - b3 = b2; - - if((b2 & pos.pieces_of_color(them)) == EmptyBoardBB) { - // There are no enemy pieces in the pawn's path! Are any of the - // squares in the pawn's path attacked by the enemy? - if(b3 == EmptyBoardBB) - // No enemy attacks, huge bonus! - ebonus += Value(tr * ((b2 == b4)? 17 : 15)); - else - // OK, there are enemy attacks. Are those squares which are - // attacked by the enemy also attacked by us? If yes, big bonus - // (but smaller than when there are no enemy attacks), if no, - // somewhat smaller bonus. - ebonus += Value(tr * (((b3 & b4) == b3)? 13 : 8)); - } - else { - // There are some enemy pieces in the pawn's path. While this is - // sad, we still assign a moderate bonus if all squares in the path - // which are either occupied by or attacked by enemy pieces are - // also attacked by us. - if(((b3 | (b2 & pos.pieces_of_color(them))) & ~b4) == EmptyBoardBB) - ebonus += Value(tr * 6); - } - // At last, add a small bonus when there are no *friendly* pieces - // in the pawn's path: - if((b2 & pos.pieces_of_color(us)) == EmptyBoardBB) - ebonus += Value(tr); - } + while (b) + { + Square s = pop_1st_bit(&b); + + assert(pos.piece_on(s) == pawn_of_color(us)); + assert(pos.pawn_is_passed(us, s)); + + int r = int(relative_rank(us, s) - RANK_2); + int tr = Max(0, r * (r - 1)); + Square blockSq = s + pawn_push(us); + + // Base bonus based on rank + Value mbonus = Value(20 * tr); + Value ebonus = Value(10 + r * r * 10); + + // Adjust bonus based on king proximity + ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr); + ebonus -= Value(square_distance(ourKingSq, blockSq + pawn_push(us)) * 1 * tr); + ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr); + + // If the pawn is free to advance, increase bonus + if (pos.square_is_empty(blockSq)) + { + b2 = squares_in_front_of(us, s); + b3 = b2 & ei.attacked_by(them); + b4 = b2 & ei.attacked_by(us); + + // If there is an enemy rook or queen attacking the pawn from behind, + // add all X-ray attacks by the rook or queen. + if ( bit_is_set(ei.attacked_by(them,ROOK) | ei.attacked_by(them,QUEEN),s) + && (squares_behind(us, s) & pos.rooks_and_queens(them))) + b3 = b2; + + if ((b2 & pos.pieces_of_color(them)) == EmptyBoardBB) + { + // There are no enemy pieces in the pawn's path! Are any of the + // squares in the pawn's path attacked by the enemy? + if (b3 == EmptyBoardBB) + // No enemy attacks, huge bonus! + ebonus += Value(tr * (b2 == b4 ? 17 : 15)); + else + // OK, there are enemy attacks. Are those squares which are + // attacked by the enemy also attacked by us? If yes, big bonus + // (but smaller than when there are no enemy attacks), if no, + // somewhat smaller bonus. + ebonus += Value(tr * ((b3 & b4) == b3 ? 13 : 8)); + } + else + { + // There are some enemy pieces in the pawn's path. While this is + // sad, we still assign a moderate bonus if all squares in the path + // which are either occupied by or attacked by enemy pieces are + // also attacked by us. + if (((b3 | (b2 & pos.pieces_of_color(them))) & ~b4) == EmptyBoardBB) + ebonus += Value(tr * 6); + } + // At last, add a small bonus when there are no *friendly* pieces + // in the pawn's path. + if ((b2 & pos.pieces_of_color(us)) == EmptyBoardBB) + ebonus += Value(tr); + } + + // If the pawn is supported by a friendly pawn, increase bonus + b2 = pos.pawns(us) & neighboring_files_bb(s); + if (b2 & rank_bb(s)) + ebonus += Value(r * 20); + else if (pos.pawn_attacks(them, s) & b2) + ebonus += Value(r * 12); + + // If the other side has only a king, check whether the pawn is + // unstoppable + if (pos.non_pawn_material(them) == Value(0)) + { + Square qsq; + int d; + + qsq = relative_square(us, make_square(square_file(s), RANK_8)); + d = square_distance(s, qsq) + - square_distance(theirKingSq, qsq) + + (us != pos.side_to_move()); - // If the pawn is supported by a friendly pawn, increase bonus. - b2 = pos.pawns(us) & neighboring_files_bb(s); - if(b2 & rank_bb(s)) - ebonus += Value(r * 20); - else if(pos.pawn_attacks(them, s) & b2) - ebonus += Value(r * 12); - - // If the other side has only a king, check whether the pawn is - // unstoppable: - if(pos.non_pawn_material(them) == Value(0)) { - Square qsq; - int d; - - qsq = relative_square(us, make_square(square_file(s), RANK_8)); - d = square_distance(s, qsq) - square_distance(theirKingSq, qsq) - + ((us == pos.side_to_move())? 0 : 1); - - if(d < 0) { - int mtg = RANK_8 - relative_rank(us, s); - int blockerCount = - count_1s_max_15(squares_in_front_of(us,s)&pos.occupied_squares()); - mtg += blockerCount; - d += blockerCount; - if(d < 0) { - hasUnstoppable[us] = true; - movesToGo[us] = Min(movesToGo[us], mtg); + if (d < 0) + { + int mtg = RANK_8 - relative_rank(us, s); + int blockerCount = count_1s_max_15(squares_in_front_of(us,s) & pos.occupied_squares()); + mtg += blockerCount; + d += blockerCount; + if (d < 0) + { + hasUnstoppable[us] = true; + movesToGo[us] = Min(movesToGo[us], mtg); + } + } + } + // Rook pawns are a special case: They are sometimes worse, and + // sometimes better than other passed pawns. It is difficult to find + // good rules for determining whether they are good or bad. For now, + // we try the following: Increase the value for rook pawns if the + // other side has no pieces apart from a knight, and decrease the + // value if the other side has a rook or queen. + if (square_file(s) == FILE_A || square_file(s) == FILE_H) + { + if( pos.non_pawn_material(them) == KnightValueMidgame // FIXME should be <= ??? + && pos.piece_count(them, KNIGHT) == 1) + ebonus += ebonus / 4; + else if(pos.rooks_and_queens(them)) + ebonus -= ebonus / 4; } - } - } - // Rook pawns are a special case: They are sometimes worse, and - // sometimes better than other passed pawns. It is difficult to find - // good rules for determining whether they are good or bad. For now, - // we try the following: Increase the value for rook pawns if the - // other side has no pieces apart from a knight, and decrease the - // value if the other side has a rook or queen. - if(square_file(s) == FILE_A || square_file(s) == FILE_H) { - if(pos.non_pawn_material(them) == KnightValueMidgame - && pos.piece_count(them, KNIGHT) == 1) - ebonus += ebonus / 4; - else if(pos.rooks_and_queens(them)) - ebonus -= ebonus / 4; - } - // Add the scores for this pawn to the middle game and endgame eval. - ei.mgValue += apply_weight(Sign[us] * mbonus, WeightPassedPawnsMidgame); - ei.egValue += apply_weight(Sign[us] * ebonus, WeightPassedPawnsEndgame); - } + // Add the scores for this pawn to the middle game and endgame eval. + ei.mgValue += apply_weight(Sign[us] * mbonus, WeightPassedPawnsMidgame); + ei.egValue += apply_weight(Sign[us] * ebonus, WeightPassedPawnsEndgame); + } } // Does either side have an unstoppable passed pawn? - if(hasUnstoppable[WHITE] && !hasUnstoppable[BLACK]) - ei.egValue += UnstoppablePawnValue - Value(0x40 * movesToGo[WHITE]); - else if(hasUnstoppable[BLACK] && !hasUnstoppable[WHITE]) - ei.egValue -= UnstoppablePawnValue - Value(0x40 * movesToGo[BLACK]); - else if(hasUnstoppable[BLACK] && hasUnstoppable[WHITE]) { - // Both sides have unstoppable pawns! Try to find out who queens - // first. We begin by transforming 'movesToGo' to the number of - // plies until the pawn queens for both sides: - movesToGo[WHITE] *= 2; - movesToGo[BLACK] *= 2; - movesToGo[pos.side_to_move()]--; - - // If one side queens at least three plies before the other, that - // side wins: - if(movesToGo[WHITE] <= movesToGo[BLACK] - 3) - ei.egValue += UnstoppablePawnValue - Value(0x40 * (movesToGo[WHITE]/2)); - else if(movesToGo[BLACK] <= movesToGo[WHITE] - 3) - ei.egValue -= UnstoppablePawnValue - Value(0x40 * (movesToGo[BLACK]/2)); - - // We could also add some rules about the situation when one side - // queens exactly one ply before the other: Does the first queen - // check the opponent's king, or attack the opponent's queening square? - // This is slightly tricky to get right, because it is possible that - // the opponent's king has moved somewhere before the first pawn queens. + if (hasUnstoppable[WHITE] && !hasUnstoppable[BLACK]) + ei.egValue += UnstoppablePawnValue - Value(0x40 * movesToGo[WHITE]); + else if (hasUnstoppable[BLACK] && !hasUnstoppable[WHITE]) + ei.egValue -= UnstoppablePawnValue - Value(0x40 * movesToGo[BLACK]); + else if (hasUnstoppable[BLACK] && hasUnstoppable[WHITE]) + { + // Both sides have unstoppable pawns! Try to find out who queens + // first. We begin by transforming 'movesToGo' to the number of + // plies until the pawn queens for both sides. + movesToGo[WHITE] *= 2; + movesToGo[BLACK] *= 2; + movesToGo[pos.side_to_move()]--; + + // If one side queens at least three plies before the other, that + // side wins. + if (movesToGo[WHITE] <= movesToGo[BLACK] - 3) + ei.egValue += UnstoppablePawnValue - Value(0x40 * (movesToGo[WHITE]/2)); + else if(movesToGo[BLACK] <= movesToGo[WHITE] - 3) + ei.egValue -= UnstoppablePawnValue - Value(0x40 * (movesToGo[BLACK]/2)); + + // We could also add some rules about the situation when one side + // queens exactly one ply before the other: Does the first queen + // check the opponent's king, or attack the opponent's queening square? + // This is slightly tricky to get right, because it is possible that + // the opponent's king has moved somewhere before the first pawn queens. } } -- 2.39.2