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Bonus for double attacks on an unsupported pawn. #2205

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Bonus for double attacks on an unsupported pawn. #2205

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ffee47f
bonus for double attacks on an unsupported pawn.
Jun 24, 2019
47c0275
bench 3809056
Jun 24, 2019
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14 changes: 10 additions & 4 deletions src/pawns.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,7 @@ namespace {
constexpr Score Doubled = S(11, 56);
constexpr Score Isolated = S( 5, 15);
constexpr Score WeakUnopposed = S( 13, 27);
constexpr Score Attacked2Unsupported = S( 0, 20);

// Connected pawn bonus
constexpr int Connected[RANK_NB] = { 0, 7, 8, 12, 29, 48, 86 };
Expand Down Expand Up @@ -75,12 +76,17 @@ namespace {
Score score = SCORE_ZERO;
const Square* pl = pos.squares<PAWN>(Us);

Bitboard ourPawns = pos.pieces( Us, PAWN);
Bitboard theirPawns = pos.pieces(Them, PAWN);
Bitboard ourPawns = pos.pieces( Us, PAWN);
Bitboard ourDoubles = pawn_double_attacks_bb<Us>(ourPawns);
Bitboard theirPawns = pos.pieces(Them, PAWN);
Bitboard theirAttacks = pawn_attacks_bb<Them>(theirPawns);

e->passedPawns[Us] = e->pawnAttacksSpan[Us] = 0;
e->kingSquares[Us] = SQ_NONE;
e->pawnAttacks[Us] = pawn_attacks_bb<Us>(ourPawns);
e->kingSquares[Us] = SQ_NONE;
e->pawnAttacks[Us] = pawn_attacks_bb<Us>(ourPawns);

//Unsupported enemy pawns attacked twice by us
score += Attacked2Unsupported * popcount(ourDoubles & theirPawns & ~theirAttacks);

// Loop through all pawns of the current color and score each pawn
while ((s = *pl++) != SQ_NONE)
Expand Down