{ S(25, 30), S(36, 35), S(40, 35), S(40, 35),
S(40, 35), S(40, 35), S(36, 35), S(25, 30) } };
- // Backward pawn penalty by opposed flag and file
- const Score Backward[2][FILE_NB] = {
- { S(30, 42), S(43, 46), S(49, 46), S(49, 46),
- S(49, 46), S(49, 46), S(43, 46), S(30, 42) },
- { S(20, 28), S(29, 31), S(33, 31), S(33, 31),
- S(33, 31), S(33, 31), S(29, 31), S(20, 28) } };
+ // Backward pawn penalty by opposed flag
+ const Score Backward[2] = { S(67, 42), S(49, 24) };
- // Connected pawn bonus by opposed, phalanx flags and rank
- Score Connected[2][2][RANK_NB];
+ // Connected pawn bonus by opposed, phalanx, twice supported and rank
+ Score Connected[2][2][2][RANK_NB];
// Levers bonus by rank
const Score Lever[RANK_NB] = {
// Unsupported pawn penalty
const Score UnsupportedPawnPenalty = S(20, 10);
+ // Center bind bonus: Two pawns controlling the same central square
+ const Bitboard CenterBindMask[COLOR_NB] = {
+ (FileDBB | FileEBB) & (Rank5BB | Rank6BB | Rank7BB),
+ (FileDBB | FileEBB) & (Rank4BB | Rank3BB | Rank2BB)
+ };
+
+ const Score CenterBind = S(16, 0);
+
// Weakness of our pawn shelter in front of the king by [distance from edge][rank]
const Value ShelterWeakness[][RANK_NB] = {
- { V(100), V(13), V(24), V(64), V(89), V( 93), V(104) },
- { V(110), V( 1), V(29), V(75), V(96), V(102), V(107) },
- { V(102), V( 0), V(39), V(74), V(88), V(101), V( 98) },
- { V( 88), V( 4), V(33), V(67), V(92), V( 94), V(107) } };
+ { V( 97), V(21), V(26), V(51), V(87), V( 89), V( 99) },
+ { V(120), V( 0), V(28), V(76), V(88), V(103), V(104) },
+ { V(101), V( 7), V(54), V(78), V(77), V( 92), V(101) },
+ { V( 80), V(11), V(44), V(68), V(87), V( 90), V(119) } };
// Danger of enemy pawns moving toward our king by [type][distance from edge][rank]
const Value StormDanger[][4][RANK_NB] = {
- { { V( 0), V( 63), V( 128), V(43), V(27) },
- { V( 0), V( 62), V( 131), V(44), V(26) },
- { V( 0), V( 59), V( 121), V(50), V(28) },
- { V( 0), V( 62), V( 127), V(54), V(28) } },
- { { V(24), V( 40), V( 93), V(42), V(22) },
- { V(24), V( 28), V( 101), V(38), V(20) },
- { V(24), V( 32), V( 95), V(36), V(23) },
- { V(27), V( 24), V( 99), V(36), V(24) } },
- { { V( 0), V( 0), V( 81), V(16), V( 6) },
- { V( 0), V( 0), V( 165), V(29), V( 9) },
- { V( 0), V( 0), V( 163), V(23), V(12) },
- { V( 0), V( 0), V( 161), V(28), V(13) } },
- { { V( 0), V(-296), V(-299), V(55), V(25) },
- { V( 0), V( 67), V( 131), V(46), V(21) },
- { V( 0), V( 65), V( 135), V(50), V(31) },
- { V( 0), V( 62), V( 128), V(51), V(24) } } };
+ { { V( 0), V( 67), V( 134), V(38), V(32) },
+ { V( 0), V( 57), V( 139), V(37), V(22) },
+ { V( 0), V( 43), V( 115), V(43), V(27) },
+ { V( 0), V( 68), V( 124), V(57), V(32) } },
+ { { V(20), V( 43), V( 100), V(56), V(20) },
+ { V(23), V( 20), V( 98), V(40), V(15) },
+ { V(23), V( 39), V( 103), V(36), V(18) },
+ { V(28), V( 19), V( 108), V(42), V(26) } },
+ { { V( 0), V( 0), V( 75), V(14), V( 2) },
+ { V( 0), V( 0), V( 150), V(30), V( 4) },
+ { V( 0), V( 0), V( 160), V(22), V( 5) },
+ { V( 0), V( 0), V( 166), V(24), V(13) } },
+ { { V( 0), V(-283), V(-281), V(57), V(31) },
+ { V( 0), V( 58), V( 141), V(39), V(18) },
+ { V( 0), V( 65), V( 142), V(48), V(32) },
+ { V( 0), V( 60), V( 126), V(51), V(19) } } };
// Max bonus for king safety. Corresponds to start position with all the pawns
// in front of the king and no enemy pawn on the horizon.
- const Value MaxSafetyBonus = V(257);
+ const Value MaxSafetyBonus = V(258);
#undef S
#undef V
const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW);
const Square Left = (Us == WHITE ? DELTA_NW : DELTA_SE);
- Bitboard b, p, doubled, connected;
+ Bitboard b, neighbours, doubled, supported, phalanx;
Square s;
- bool passed, isolated, opposed, phalanx, backward, unsupported, lever;
+ bool passed, isolated, opposed, backward, lever, connected;
Score score = SCORE_ZERO;
- const Square* pl = pos.
list<PAWN>(Us);
+ const Square* pl = pos.
squares<PAWN>(Us);
const Bitboard* pawnAttacksBB = StepAttacksBB[make_piece(Us, PAWN)];
Bitboard ourPawns = pos.pieces(Us , PAWN);
// This file cannot be semi-open
e->semiopenFiles[Us] &= ~(1 << f);
- // Previous rank
- p = rank_bb(s - pawn_push(Us));
-
- // Flag the pawn as passed, isolated, doubled,
- // unsupported or connected (but not the backward one).
- connected = ourPawns & adjacent_files_bb(f) & (rank_bb(s) | p);
- phalanx = connected & rank_bb(s);
- unsupported = !(ourPawns & adjacent_files_bb(f) & p);
- isolated = !(ourPawns & adjacent_files_bb(f));
+ // Flag the pawn
+ neighbours = ourPawns & adjacent_files_bb(f);
doubled = ourPawns & forward_bb(Us, s);
opposed = theirPawns & forward_bb(Us, s);
passed = !(theirPawns & passed_pawn_mask(Us, s));
lever = theirPawns & pawnAttacksBB[s];
+ phalanx = neighbours & rank_bb(s);
+ supported = neighbours & rank_bb(s - Up);
+ connected = supported | phalanx;
+ isolated = !neighbours;
// Test for backward pawn.
- // If the pawn is passed, isolated, or connected it cannot be
+ // If the pawn is passed, isolated, lever or connected it cannot be
// backward. If there are friendly pawns behind on adjacent files
- // or if it can capture an enemy pawn it cannot be backward either.
- if ( (passed | isolated | connected)
+ // or if it is sufficiently advanced, it cannot be backward either.
+ if ( (passed | isolated | lever | connected)
|| (ourPawns & pawn_attack_span(Them, s))
- || (pos.attacks_from<PAWN>(s, Us) & theirPawns))
+ || (relative_rank(Us, s) >= RANK_5))
backward = false;
else
{
- // We now know that there are no friendly pawns beside or behind this
+ // We now know there are no friendly pawns beside or behind this
// pawn on adjacent files. We now check whether the pawn is
// backward by looking in the forward direction on the adjacent
// files, and picking the closest pawn there.
if (isolated)
score -= Isolated[opposed][f];
- if (unsupported && !isolated)
+ else if (backward)
+ score -= Backward[opposed];
+
+ else if (!supported)
score -= UnsupportedPawnPenalty;
+ if (connected)
+ score += Connected[opposed][!!phalanx][more_than_one(supported)][relative_rank(Us, s)];
+
if (doubled)
score -= Doubled[f] / distance<Rank>(s, frontmost_sq(Us, doubled));
- if (backward)
- score -= Backward[opposed][f];
-
- if (connected)
- score += Connected[opposed][phalanx][relative_rank(Us, s)];
-
if (lever)
score += Lever[relative_rank(Us, s)];
}
b = e->semiopenFiles[Us] ^ 0xFF;
e->pawnSpan[Us] = b ? int(msb(b) - lsb(b)) : 0;
+ // Center binds: Two pawns controlling the same central square
+ b = shift_bb<Right>(ourPawns) & shift_bb<Left>(ourPawns) & CenterBindMask[Us];
+ score += popcount<Max15>(b) * CenterBind;
+
return score;
}
for (int opposed = 0; opposed <= 1; ++opposed)
for (int phalanx = 0; phalanx <= 1; ++phalanx)
- for (Rank r = RANK_2; r < RANK_8; ++r)
- {
- int bonus = Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0);
- Connected[opposed][phalanx][r] = make_score(bonus / 2, bonus >> opposed);
- }
+ for (int apex = 0; apex <= 1; ++apex)
+ for (Rank r = RANK_2; r < RANK_8; ++r)
+ {
+ int v = (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed;
+ v += (apex ? v / 2 : 0);
+ Connected[opposed][phalanx][apex][r] = make_score(3 * v / 2, v);
+ }
}
kingSquares[Us] = ksq;
castlingRights[Us] = pos.can_castle(Us);
- minKingPawnDistance[Us] = 0;
+ int minKingPawnDistance = 0;
Bitboard pawns = pos.pieces(Us, PAWN);
if (pawns)
- while (!(DistanceRingBB[ksq][minKingPawnDistance[Us]++] & pawns)) {}
+ while (!(DistanceRingBB[ksq][minKingPawnDistance++] & pawns)) {}
if (relative_rank(Us, ksq) > RANK_4)
- return make_score(0, -16 * minKingPawnDistance[Us]);
+ return make_score(0, -16 * minKingPawnDistance);
Value bonus = shelter_storm<Us>(pos, ksq);
if (pos.can_castle(MakeCastling<Us, QUEEN_SIDE>::right))
bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_C1)));
- return make_score(bonus, -16 * minKingPawnDistance[Us]);
+ return make_score(bonus, -16 * minKingPawnDistance);
}
// Explicit template instantiation
projects / stockfish / blobdiff