- // Isolated pawn penalty by opposed flag and file
- const Score Isolated[2][FILE_NB] = {
- { S(31, 36), S(45, 41), S(50, 41), S(50, 41),
- S(50, 41), S(50, 41), S(45, 41), S(31, 36) },
- { S(21, 24), S(30, 28), S(33, 28), S(33, 28),
- S(33, 28), S(33, 28), S(30, 28), S(21, 24) } };
-
- // Backward pawn penalty by opposed flag
- const Score Backward[2] = { S(56, 33), S(41, 19) };
-
- // Unsupported pawn penalty for pawns which are neither isolated or backward,
- // by number of pawns it supports [less than 2 / exactly 2].
- const Score Unsupported[2] = { S(17, 8), S(21, 12) };
-
- // Connected pawn bonus by opposed, phalanx, twice supported and rank
- Score Connected[2][2][2][RANK_NB];
-
- // Doubled pawn penalty by file
- const Score Doubled[FILE_NB] = {
- S(11, 34), S(17, 38), S(19, 38), S(19, 38),
- S(19, 38), S(19, 38), S(17, 38), S(11, 34) };
-
- // Lever bonus by rank
- const Score Lever[RANK_NB] = {
- S( 0, 0), S( 0, 0), S(0, 0), S(0, 0),
- S(17, 16), S(33, 32), S(0, 0), S(0, 0) };
-
- // Weakness of our pawn shelter in front of the king by [distance from edge][rank]
- const Value ShelterWeakness[][RANK_NB] = {
- { 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]
+ // Isolated pawn penalty
+ const Score Isolated = S(13, 18);
+
+ // Backward pawn penalty
+ const Score Backward = S(24, 12);
+
+ // Connected pawn bonus by opposed, phalanx, #support and rank
+ Score Connected[2][2][3][RANK_NB];
+
+ // Doubled pawn penalty
+ const Score Doubled = S(18, 38);
+
+ // Weakness of our pawn shelter in front of the king by [isKingFile][distance from edge][rank].
+ // RANK_1 = 0 is used for files where we have no pawns or our pawn is behind our king.
+ const Value ShelterWeakness[][int(FILE_NB) / 2][RANK_NB] = {
+ { { V( 97), V(17), V( 9), V(44), V( 84), V( 87), V( 99) }, // Not On King file
+ { V(106), V( 6), V(33), V(86), V( 87), V(104), V(112) },
+ { V(101), V( 2), V(65), V(98), V( 58), V( 89), V(115) },
+ { V( 73), V( 7), V(54), V(73), V( 84), V( 83), V(111) } },
+ { { V(104), V(20), V( 6), V(27), V( 86), V( 93), V( 82) }, // On King file
+ { V(123), V( 9), V(34), V(96), V(112), V( 88), V( 75) },
+ { V(120), V(25), V(65), V(91), V( 66), V( 78), V(117) },
+ { V( 81), V( 2), V(47), V(63), V( 94), V( 93), V(104) } }
+ };
+
+ // Danger of enemy pawns moving toward our king by [type][distance from edge][rank].
+ // For the unopposed and unblocked cases, RANK_1 = 0 is used when opponent has
+ // no pawn on the given file, or their pawn is behind our king.