Remove attacked pawns from storm evaluation

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index f9dbcae2932f01a2c8a3d7381af8d183fd42f452..8354cc1510fb98de3facd3511555e141f9b89c09 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -33,12 +33,13 @@ namespace {
 
   // Pawn penalties
   constexpr Score Backward      = S( 9, 24);
-  constexpr Score BlockedStorm  = S(82, 82);
   constexpr Score Doubled       = S(11, 56);
   constexpr Score Isolated      = S( 5, 15);
   constexpr Score WeakLever     = S( 0, 56);
   constexpr Score WeakUnopposed = S(13, 27);
 
+  constexpr Score BlockedStorm[RANK_NB]  = {S( 0, 0), S( 0, 0), S( 76, 78), S(-10, 15), S(-7, 10), S(-4, 6), S(-1, 2)};
+
   // Connected pawn bonus
   constexpr int Connected[RANK_NB] = { 0, 7, 8, 12, 29, 48, 86 };
 
@@ -200,8 +201,8 @@ Score Entry::evaluate_shelter(const Position& pos, Square ksq) {
   constexpr Color Them = ~Us;
 
   Bitboard b = pos.pieces(PAWN) & ~forward_ranks_bb(Them, ksq);
-  Bitboard ourPawns = b & pos.pieces(Us);
-  Bitboard theirPawns = b & pos.pieces(Them);
+  Bitboard ourPawns = b & pos.pieces(Us) & ~pawnAttacks[Them];
+  Bitboard theirPawns = b & pos.pieces(Them) & ~pawnAttacks[Us];
 
   Score bonus = make_score(5, 5);
 
@@ -218,7 +219,7 @@ Score Entry::evaluate_shelter(const Position& pos, Square ksq) {
       bonus += make_score(ShelterStrength[d][ourRank], 0);
 
       if (ourRank && (ourRank == theirRank - 1))
-          bonus -= BlockedStorm * int(theirRank == RANK_3);
+          bonus -= BlockedStorm[theirRank];
       else
           bonus -= make_score(UnblockedStorm[d][theirRank], 0);
   }