- // Doubled pawn penalty by opposed flag and file
- const Score DoubledPawnPenalty[2][8] = {
- { S(13, 43), S(20, 48), S(23, 48), S(23, 48),
- S(23, 48), S(23, 48), S(20, 48), S(13, 43) },
- { S(13, 43), S(20, 48), S(23, 48), S(23, 48),
- S(23, 48), S(23, 48), S(20, 48), S(13, 43) }};
-
- // Isolated pawn penalty by opposed flag and file
- const Score IsolatedPawnPenalty[2][8] = {
- { S(37, 45), S(54, 52), S(60, 52), S(60, 52),
- S(60, 52), S(60, 52), S(54, 52), S(37, 45) },
- { 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 BackwardPawnPenalty[2][8] = {
- { 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) }};
-
- // Pawn chain membership bonus by file
- const Score ChainBonus[8] = {
- S(11,-1), S(13,-1), S(13,-1), S(14,-1),
- S(14,-1), S(13,-1), S(13,-1), S(11,-1)
+ // Pawn penalties
+ constexpr Score Isolated = S(13, 16);
+ constexpr Score Backward = S(17, 11);
+ constexpr Score Doubled = S(13, 40);
+
+ // Connected pawn bonus by opposed, phalanx, #support and rank
+ Score Connected[2][2][3][RANK_NB];
+
+ // 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.
+ constexpr Value ShelterStrength[int(FILE_NB) / 2][RANK_NB] = {
+ { V( 7), V(76), V( 84), V( 38), V( 7), V( 30), V(-19) },
+ { V(-13), V(83), V( 42), V(-27), V( 2), V(-32), V(-45) },
+ { V(-26), V(63), V( 5), V(-44), V( -5), V( 2), V(-59) },
+ { V(-19), V(53), V(-11), V(-22), V(-12), V(-51), V(-60) }