// Pawn penalties
constexpr Score Backward = S( 9, 24);
- constexpr Score BlockedStorm = S(82, 82);
constexpr Score Doubled = S(11, 56);
constexpr Score Isolated = S( 5, 15);
constexpr Score WeakLever = S( 0, 56);
constexpr Score WeakUnopposed = S(13, 27);
+ constexpr Score BlockedStorm[RANK_NB] = {S( 0, 0), S( 0, 0), S( 76, 78), S(-10, 15), S(-7, 10), S(-4, 6), S(-1, 2)};
+
// Connected pawn bonus
constexpr int Connected[RANK_NB] = { 0, 7, 8, 12, 29, 48, 86 };
template<Color Us>
Score evaluate(const Position& pos, Pawns::Entry* e) {
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Color Them = ~Us;
constexpr Direction Up = pawn_push(Us);
Bitboard neighbours, stoppers, support, phalanx, opposed;
e->passedPawns[Us] = 0;
e->kingSquares[Us] = SQ_NONE;
e->pawnAttacks[Us] = e->pawnAttacksSpan[Us] = pawn_attacks_bb<Us>(ourPawns);
+ e->blockedCount += popcount(shift<Up>(ourPawns) & (theirPawns | doubleAttackThem));
// Loop through all pawns of the current color and score each pawn
while ((s = *pl++) != SQ_NONE)
opposed = theirPawns & forward_file_bb(Us, s);
blocked = theirPawns & (s + Up);
stoppers = theirPawns & passed_pawn_span(Us, s);
- lever = theirPawns & PawnAttacks[Us][s];
- leverPush = theirPawns & PawnAttacks[Us][s + Up];
+ lever = theirPawns & pawn_attacks_bb(Us, s);
+ leverPush = theirPawns & pawn_attacks_bb(Us, s + Up);
doubled = ourPawns & (s - Up);
neighbours = ourPawns & adjacent_files_bb(s);
phalanx = neighbours & rank_bb(s);
// (a) there is no stoppers except some levers
// (b) the only stoppers are the leverPush, but we outnumber them
// (c) there is only one front stopper which can be levered.
+ // (Refined in Evaluation::passed)
passed = !(stoppers ^ lever)
|| ( !(stoppers ^ leverPush)
&& popcount(phalanx) >= popcount(leverPush))
|| ( stoppers == blocked && r >= RANK_5
&& (shift<Up>(support) & ~(theirPawns | doubleAttackThem)));
+ passed &= !(forward_file_bb(Us, s) & ourPawns);
+
// Passed pawns will be properly scored later in evaluation when we have
// full attack info.
if (passed)
// Score this pawn
if (support | phalanx)
{
- int v = Connected[r] * (2 + bool(phalanx) - bool(opposed))
+ int v = Connected[r] * (4 + 2 * bool(phalanx) - 2 * bool(opposed) - bool(blocked)) / 2
+ 21 * popcount(support);
score += make_score(v, v * (r - 2) / 4);
}
else if (!neighbours)
- score -= Isolated
- + WeakUnopposed * !opposed;
+ {
+ if ( opposed
+ && (ourPawns & forward_file_bb(Them, s))
+ && !(theirPawns & adjacent_files_bb(s)))
+ score -= Doubled;
+ else
+ score -= Isolated
+ + WeakUnopposed * !opposed;
+ }
else if (backward)
- score -= Backward
- + WeakUnopposed * !opposed;
+ score -= Backward
+ + WeakUnopposed * !opposed;
if (!support)
- score -= Doubled * doubled
- + WeakLever * more_than_one(lever);
+ score -= Doubled * doubled
+ + WeakLever * more_than_one(lever);
}
return score;
return e;
e->key = key;
+ e->blockedCount = 0;
e->scores[WHITE] = evaluate<WHITE>(pos, e);
e->scores[BLACK] = evaluate<BLACK>(pos, e);
/// penalty for a king, looking at the king file and the two closest files.
template<Color Us>
-Score Entry::evaluate_shelter(const Position& pos, Square ksq) {
+Score Entry::evaluate_shelter(const Position& pos, Square ksq) const {
- constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Color Them = ~Us;
Bitboard b = pos.pieces(PAWN) & ~forward_ranks_bb(Them, ksq);
- Bitboard ourPawns = b & pos.pieces(Us);
+ Bitboard ourPawns = b & pos.pieces(Us) & ~pawnAttacks[Them];
Bitboard theirPawns = b & pos.pieces(Them);
Score bonus = make_score(5, 5);
b = theirPawns & file_bb(f);
int theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0;
- File d = edge_distance(f);
+ int d = edge_distance(f);
bonus += make_score(ShelterStrength[d][ourRank], 0);
if (ourRank && (ourRank == theirRank - 1))
- bonus -= BlockedStorm * int(theirRank == RANK_3);
+ bonus -= BlockedStorm[theirRank];
else
bonus -= make_score(UnblockedStorm[d][theirRank], 0);
}
// In endgame we like to bring our king near our closest pawn
Bitboard pawns = pos.pieces(Us, PAWN);
- int minPawnDist = pawns ? 8 : 0;
+ int minPawnDist = 6;
- if (pawns & PseudoAttacks[KING][ksq])
+ if (pawns & attacks_bb<KING>(ksq))
minPawnDist = 1;
else while (pawns)
minPawnDist = std::min(minPawnDist, distance(ksq, pop_lsb(&pawns)));