{ S(20, 28), S(29, 31), S(33, 31), S(33, 31),
S(33, 31), S(33, 31), S(29, 31), S(20, 28) }};
- // Pawn chain membership bonus by file
- const Score ChainMember[FILE_NB][RANK_NB] = {
- { S(0, 0), S(14, 0), S(16, 4), S(18, 9), S(28, 28), S(52, 104), S(118, 236) },
- { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(30, 30), S(54, 108), S(120, 240) },
- { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(30, 30), S(54, 108), S(120, 240) },
- { S(0, 0), S(17, 0), S(19, 6), S(22, 11), S(33, 33), S(59, 118), S(127, 254) },
- { S(0, 0), S(17, 0), S(19, 6), S(22, 11), S(33, 33), S(59, 118), S(127, 254) },
- { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(30, 30), S(54, 108), S(120, 240) },
- { S(0, 0), S(16, 0), S(18, 5), S(20, 10), S(30, 30), S(54, 108), S(120, 240) },
- { S(0, 0), S(14, 0), S(16, 4), S(18, 9), S(28, 28), S(52, 104), S(118, 236) }};
+ // Pawn chain membership bonus by file and rank (initialized by formula)
+ Score ChainMember[FILE_NB][RANK_NB];
// Candidate passed pawn bonus by rank
const Score CandidatePassed[RANK_NB] = {
namespace Pawns {
+/// init() initializes some tables by formula instead of hard-code their values
+
+void init() {
+
+ const int chainByFile[8] = { 1, 3, 3, 4, 4, 3, 3, 1 };
+ int bonus;
+
+ for (Rank r = RANK_1; r < RANK_8; ++r)
+ for (File f = FILE_A; f <= FILE_H; ++f)
+ {
+ bonus = r * (r-1) * (r-2) + chainByFile[f] * (r/2 + 1);
+ ChainMember[f][r] = make_score(bonus, bonus);
+ }
+}
+
+
/// probe() takes a position object as input, computes a Entry object, and returns
/// a pointer to it. The result is also stored in a hash table, so we don't have
/// to recompute everything when the same pawn structure occurs again.