constexpr Score Doubled = S(11, 56);
constexpr Score Isolated = S( 5, 15);
- // Connected pawn bonus by opposed, phalanx, #support and rank
- Score Connected[2][2][3][RANK_NB];
+ // Connected pawn bonus
+ constexpr int Connected[RANK_NB] = { 0, 13, 24, 18, 65, 100, 175, 330 };
// Strength of pawn shelter for our king by [distance from edge][rank].
// RANK_1 = 0 is used for files where we have no pawn, or pawn is behind our king.
// Score this pawn
if (support | phalanx)
- score += Connected[opposed][bool(phalanx)][popcount(support)][relative_rank(Us, s)];
-
+ {
+ int r = relative_rank(Us, s);
+ int v = phalanx ? Connected[r] + Connected[r + 1] : 2 * Connected[r];
+ v = 17 * popcount(support) + (v >> (opposed + 1));
+ score += make_score(v, v * (r - 2) / 4);
+ }
else if (!neighbours)
score -= Isolated, e->weakUnopposed[Us] += !opposed;
namespace Pawns {
-/// Pawns::init() initializes some tables needed by evaluation. Instead of using
-/// hard-coded tables, when makes sense, we prefer to calculate them with a formula
-/// to reduce independent parameters and to allow easier tuning and better insight.
-
-void init() {
-
- static constexpr int Seed[RANK_NB] = { 0, 13, 24, 18, 65, 100, 175, 330 };
-
- for (int opposed = 0; opposed <= 1; ++opposed)
- for (int phalanx = 0; phalanx <= 1; ++phalanx)
- for (int support = 0; support <= 2; ++support)
- for (Rank r = RANK_2; r < RANK_8; ++r)
- {
- int v = 17 * support;
- v += (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed;
-
- Connected[opposed][phalanx][support][r] = make_score(v, v * (r - 2) / 4);
- }
-}
-
-
/// Pawns::probe() looks up the current position's pawns configuration in
/// the pawns hash table. It returns a pointer to the Entry if the position
/// is found. Otherwise a new Entry is computed and stored there, so we don't