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Space inflate evaluate_passed_pawns()
No functional change. Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
parent
d0804341c5
commit
e236a0c652
1 changed files with 134 additions and 124 deletions
258
src/evaluate.cpp
258
src/evaluate.cpp
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@ -905,148 +905,158 @@ namespace {
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// evaluate_passed_pawns() evaluates the passed pawns for both sides.
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void evaluate_passed_pawns(const Position &pos, EvalInfo &ei) {
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bool hasUnstoppable[2] = {false, false};
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int movesToGo[2] = {100, 100};
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for(Color us = WHITE; us <= BLACK; us++) {
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Color them = opposite_color(us);
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Square ourKingSq = pos.king_square(us);
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Square theirKingSq = pos.king_square(them);
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Bitboard b = ei.pi->passed_pawns() & pos.pawns(us), b2, b3, b4;
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for (Color us = WHITE; us <= BLACK; us++)
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{
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Color them = opposite_color(us);
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Square ourKingSq = pos.king_square(us);
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Square theirKingSq = pos.king_square(them);
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Bitboard b = ei.pi->passed_pawns() & pos.pawns(us), b2, b3, b4;
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while(b) {
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Square s = pop_1st_bit(&b);
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assert(pos.piece_on(s) == pawn_of_color(us));
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assert(pos.pawn_is_passed(us, s));
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while (b)
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{
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Square s = pop_1st_bit(&b);
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int r = int(relative_rank(us, s) - RANK_2);
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int tr = Max(0, r * (r-1));
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Square blockSq = s + pawn_push(us);
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assert(pos.piece_on(s) == pawn_of_color(us));
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assert(pos.pawn_is_passed(us, s));
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// Base bonus based on rank:
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Value mbonus = Value(20 * tr);
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Value ebonus = Value(10 + r * r * 10);
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int r = int(relative_rank(us, s) - RANK_2);
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int tr = Max(0, r * (r - 1));
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Square blockSq = s + pawn_push(us);
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// Adjust bonus based on king proximity:
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ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr);
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ebonus -=
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Value(square_distance(ourKingSq, blockSq + pawn_push(us)) * 1 * tr);
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ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr);
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// Base bonus based on rank
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Value mbonus = Value(20 * tr);
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Value ebonus = Value(10 + r * r * 10);
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// If the pawn is free to advance, increase bonus:
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if(pos.square_is_empty(blockSq)) {
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// Adjust bonus based on king proximity
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ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr);
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ebonus -= Value(square_distance(ourKingSq, blockSq + pawn_push(us)) * 1 * tr);
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ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr);
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b2 = squares_in_front_of(us, s);
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b3 = b2 & ei.attacked_by(them);
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b4 = b2 & ei.attacked_by(us);
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// If the pawn is free to advance, increase bonus
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if (pos.square_is_empty(blockSq))
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{
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b2 = squares_in_front_of(us, s);
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b3 = b2 & ei.attacked_by(them);
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b4 = b2 & ei.attacked_by(us);
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// If there is an enemy rook or queen attacking the pawn from behind,
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// add all X-ray attacks by the rook or queen.
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if(bit_is_set(ei.attacked_by(them,ROOK)|ei.attacked_by(them,QUEEN),s)
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&& squares_behind(us, s) & pos.rooks_and_queens(them))
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b3 = b2;
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// If there is an enemy rook or queen attacking the pawn from behind,
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// add all X-ray attacks by the rook or queen.
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if ( bit_is_set(ei.attacked_by(them,ROOK) | ei.attacked_by(them,QUEEN),s)
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&& (squares_behind(us, s) & pos.rooks_and_queens(them)))
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b3 = b2;
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if((b2 & pos.pieces_of_color(them)) == EmptyBoardBB) {
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// There are no enemy pieces in the pawn's path! Are any of the
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// squares in the pawn's path attacked by the enemy?
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if(b3 == EmptyBoardBB)
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// No enemy attacks, huge bonus!
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ebonus += Value(tr * ((b2 == b4)? 17 : 15));
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else
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// OK, there are enemy attacks. Are those squares which are
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// attacked by the enemy also attacked by us? If yes, big bonus
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// (but smaller than when there are no enemy attacks), if no,
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// somewhat smaller bonus.
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ebonus += Value(tr * (((b3 & b4) == b3)? 13 : 8));
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}
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else {
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// There are some enemy pieces in the pawn's path. While this is
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// sad, we still assign a moderate bonus if all squares in the path
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// which are either occupied by or attacked by enemy pieces are
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// also attacked by us.
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if(((b3 | (b2 & pos.pieces_of_color(them))) & ~b4) == EmptyBoardBB)
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ebonus += Value(tr * 6);
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}
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// At last, add a small bonus when there are no *friendly* pieces
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// in the pawn's path:
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if((b2 & pos.pieces_of_color(us)) == EmptyBoardBB)
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ebonus += Value(tr);
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}
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// If the pawn is supported by a friendly pawn, increase bonus.
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b2 = pos.pawns(us) & neighboring_files_bb(s);
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if(b2 & rank_bb(s))
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ebonus += Value(r * 20);
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else if(pos.pawn_attacks(them, s) & b2)
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ebonus += Value(r * 12);
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// If the other side has only a king, check whether the pawn is
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// unstoppable:
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if(pos.non_pawn_material(them) == Value(0)) {
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Square qsq;
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int d;
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qsq = relative_square(us, make_square(square_file(s), RANK_8));
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d = square_distance(s, qsq) - square_distance(theirKingSq, qsq)
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+ ((us == pos.side_to_move())? 0 : 1);
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if(d < 0) {
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int mtg = RANK_8 - relative_rank(us, s);
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int blockerCount =
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count_1s_max_15(squares_in_front_of(us,s)&pos.occupied_squares());
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mtg += blockerCount;
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d += blockerCount;
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if(d < 0) {
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hasUnstoppable[us] = true;
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movesToGo[us] = Min(movesToGo[us], mtg);
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if ((b2 & pos.pieces_of_color(them)) == EmptyBoardBB)
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{
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// There are no enemy pieces in the pawn's path! Are any of the
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// squares in the pawn's path attacked by the enemy?
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if (b3 == EmptyBoardBB)
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// No enemy attacks, huge bonus!
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ebonus += Value(tr * (b2 == b4 ? 17 : 15));
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else
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// OK, there are enemy attacks. Are those squares which are
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// attacked by the enemy also attacked by us? If yes, big bonus
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// (but smaller than when there are no enemy attacks), if no,
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// somewhat smaller bonus.
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ebonus += Value(tr * ((b3 & b4) == b3 ? 13 : 8));
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}
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else
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{
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// There are some enemy pieces in the pawn's path. While this is
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// sad, we still assign a moderate bonus if all squares in the path
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// which are either occupied by or attacked by enemy pieces are
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// also attacked by us.
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if (((b3 | (b2 & pos.pieces_of_color(them))) & ~b4) == EmptyBoardBB)
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ebonus += Value(tr * 6);
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}
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// At last, add a small bonus when there are no *friendly* pieces
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// in the pawn's path.
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if ((b2 & pos.pieces_of_color(us)) == EmptyBoardBB)
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ebonus += Value(tr);
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}
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}
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}
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// Rook pawns are a special case: They are sometimes worse, and
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// sometimes better than other passed pawns. It is difficult to find
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// good rules for determining whether they are good or bad. For now,
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// we try the following: Increase the value for rook pawns if the
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// other side has no pieces apart from a knight, and decrease the
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// value if the other side has a rook or queen.
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if(square_file(s) == FILE_A || square_file(s) == FILE_H) {
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if(pos.non_pawn_material(them) == KnightValueMidgame
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&& pos.piece_count(them, KNIGHT) == 1)
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ebonus += ebonus / 4;
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else if(pos.rooks_and_queens(them))
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ebonus -= ebonus / 4;
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}
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// Add the scores for this pawn to the middle game and endgame eval.
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ei.mgValue += apply_weight(Sign[us] * mbonus, WeightPassedPawnsMidgame);
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ei.egValue += apply_weight(Sign[us] * ebonus, WeightPassedPawnsEndgame);
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}
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// If the pawn is supported by a friendly pawn, increase bonus
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b2 = pos.pawns(us) & neighboring_files_bb(s);
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if (b2 & rank_bb(s))
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ebonus += Value(r * 20);
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else if (pos.pawn_attacks(them, s) & b2)
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ebonus += Value(r * 12);
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// If the other side has only a king, check whether the pawn is
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// unstoppable
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if (pos.non_pawn_material(them) == Value(0))
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{
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Square qsq;
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int d;
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qsq = relative_square(us, make_square(square_file(s), RANK_8));
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d = square_distance(s, qsq)
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- square_distance(theirKingSq, qsq)
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+ (us != pos.side_to_move());
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if (d < 0)
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{
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int mtg = RANK_8 - relative_rank(us, s);
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int blockerCount = count_1s_max_15(squares_in_front_of(us,s) & pos.occupied_squares());
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mtg += blockerCount;
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d += blockerCount;
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if (d < 0)
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{
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hasUnstoppable[us] = true;
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movesToGo[us] = Min(movesToGo[us], mtg);
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}
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}
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}
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// Rook pawns are a special case: They are sometimes worse, and
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// sometimes better than other passed pawns. It is difficult to find
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// good rules for determining whether they are good or bad. For now,
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// we try the following: Increase the value for rook pawns if the
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// other side has no pieces apart from a knight, and decrease the
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// value if the other side has a rook or queen.
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if (square_file(s) == FILE_A || square_file(s) == FILE_H)
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{
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if( pos.non_pawn_material(them) == KnightValueMidgame // FIXME should be <= ???
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&& pos.piece_count(them, KNIGHT) == 1)
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ebonus += ebonus / 4;
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else if(pos.rooks_and_queens(them))
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ebonus -= ebonus / 4;
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}
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// Add the scores for this pawn to the middle game and endgame eval.
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ei.mgValue += apply_weight(Sign[us] * mbonus, WeightPassedPawnsMidgame);
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ei.egValue += apply_weight(Sign[us] * ebonus, WeightPassedPawnsEndgame);
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}
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}
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// Does either side have an unstoppable passed pawn?
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if(hasUnstoppable[WHITE] && !hasUnstoppable[BLACK])
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ei.egValue += UnstoppablePawnValue - Value(0x40 * movesToGo[WHITE]);
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else if(hasUnstoppable[BLACK] && !hasUnstoppable[WHITE])
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ei.egValue -= UnstoppablePawnValue - Value(0x40 * movesToGo[BLACK]);
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else if(hasUnstoppable[BLACK] && hasUnstoppable[WHITE]) {
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// Both sides have unstoppable pawns! Try to find out who queens
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// first. We begin by transforming 'movesToGo' to the number of
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// plies until the pawn queens for both sides:
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movesToGo[WHITE] *= 2;
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movesToGo[BLACK] *= 2;
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movesToGo[pos.side_to_move()]--;
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if (hasUnstoppable[WHITE] && !hasUnstoppable[BLACK])
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ei.egValue += UnstoppablePawnValue - Value(0x40 * movesToGo[WHITE]);
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else if (hasUnstoppable[BLACK] && !hasUnstoppable[WHITE])
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ei.egValue -= UnstoppablePawnValue - Value(0x40 * movesToGo[BLACK]);
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else if (hasUnstoppable[BLACK] && hasUnstoppable[WHITE])
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{
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// Both sides have unstoppable pawns! Try to find out who queens
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// first. We begin by transforming 'movesToGo' to the number of
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// plies until the pawn queens for both sides.
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movesToGo[WHITE] *= 2;
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movesToGo[BLACK] *= 2;
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movesToGo[pos.side_to_move()]--;
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// If one side queens at least three plies before the other, that
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// side wins:
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if(movesToGo[WHITE] <= movesToGo[BLACK] - 3)
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ei.egValue += UnstoppablePawnValue - Value(0x40 * (movesToGo[WHITE]/2));
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else if(movesToGo[BLACK] <= movesToGo[WHITE] - 3)
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ei.egValue -= UnstoppablePawnValue - Value(0x40 * (movesToGo[BLACK]/2));
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// If one side queens at least three plies before the other, that
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// side wins.
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if (movesToGo[WHITE] <= movesToGo[BLACK] - 3)
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ei.egValue += UnstoppablePawnValue - Value(0x40 * (movesToGo[WHITE]/2));
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else if(movesToGo[BLACK] <= movesToGo[WHITE] - 3)
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ei.egValue -= UnstoppablePawnValue - Value(0x40 * (movesToGo[BLACK]/2));
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// We could also add some rules about the situation when one side
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// queens exactly one ply before the other: Does the first queen
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// check the opponent's king, or attack the opponent's queening square?
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// This is slightly tricky to get right, because it is possible that
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// the opponent's king has moved somewhere before the first pawn queens.
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// We could also add some rules about the situation when one side
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// queens exactly one ply before the other: Does the first queen
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// check the opponent's king, or attack the opponent's queening square?
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// This is slightly tricky to get right, because it is possible that
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// the opponent's king has moved somewhere before the first pawn queens.
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}
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}
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