Simplify the shelter mask

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index 56f5d7239594b391e13ddd6b3edd80432632297f..7b3dd8181ef9fc602b6868a4eba4a1d1a81bef77 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -68,10 +68,10 @@ namespace {
       { V( 1),  V(  64), V( 143), V(26), V(13) },
       { V( 1),  V(  47), V( 110), V(44), V(24) },
       { V( 0),  V(  72), V( 127), V(50), V(31) } },
-    { { V( 0),  V(   0), V(  79), V(23), V( 1) },  // BlockedByPawn
-      { V( 0),  V(   0), V( 148), V(27), V( 2) },
-      { V( 0),  V(   0), V( 161), V(16), V( 1) },
-      { V( 0),  V(   0), V( 171), V(22), V(15) } },
+    { { V( 0),  V(   0), V(  19), V(23), V( 1) },  // BlockedByPawn
+      { V( 0),  V(   0), V(  88), V(27), V( 2) },
+      { V( 0),  V(   0), V( 101), V(16), V( 1) },
+      { V( 0),  V(   0), V( 111), V(22), V(15) } },
     { { V(22),  V(  45), V( 104), V(62), V( 6) },  // Unblocked
       { V(31),  V(  30), V(  99), V(39), V(19) },
       { V(23),  V(  29), V(  96), V(41), V(15) },
@@ -151,7 +151,7 @@ namespace {
         // not attacked more times than defended.
         if (   !(stoppers ^ lever ^ leverPush)
             && !(ourPawns & forward_file_bb(Us, s))
-            && popcount(supported) >= popcount(lever)
+            && popcount(supported) >= popcount(lever) - 1
             && popcount(phalanx)   >= popcount(leverPush))
             e->passedPawns[Us] |= s;
 
@@ -237,23 +237,15 @@ template<Color Us>
 Value Entry::shelter_storm(const Position& pos, Square ksq) {
 
   constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
-  constexpr Bitboard ShelterMask =
-                Us == WHITE ? make_bitboard(SQ_A2, SQ_B3, SQ_C2, SQ_F2, SQ_G3, SQ_H2)
-                            : make_bitboard(SQ_A7, SQ_B6, SQ_C7, SQ_F7, SQ_G6, SQ_H7);
-  constexpr Bitboard StormMask =
-                Us == WHITE ? make_bitboard(SQ_A3, SQ_C3, SQ_F3, SQ_H3)
-                            : make_bitboard(SQ_A6, SQ_C6, SQ_F6, SQ_H6);
 
   enum { BlockedByKing, Unopposed, BlockedByPawn, Unblocked };
 
-  File center = std::max(FILE_B, std::min(FILE_G, file_of(ksq)));
-  Bitboard b =   pos.pieces(PAWN)
-               & (forward_ranks_bb(Us, ksq) | rank_bb(ksq))
-               & (adjacent_files_bb(center) | file_bb(center));
+  Bitboard b = pos.pieces(PAWN) & (forward_ranks_bb(Us, ksq) | rank_bb(ksq));
   Bitboard ourPawns = b & pos.pieces(Us);
   Bitboard theirPawns = b & pos.pieces(Them);
   Value safety = MaxSafetyBonus;
 
+  File center = std::max(FILE_B, std::min(FILE_G, file_of(ksq)));
   for (File f = File(center - 1); f <= File(center + 1); ++f)
   {
       b = ourPawns & file_bb(f);
@@ -271,9 +263,6 @@ Value Entry::shelter_storm(const Position& pos, Square ksq) {
                  [d][rkThem];
   }
 
-  if (popcount((ourPawns & ShelterMask) | (theirPawns & StormMask)) == 5)
-      safety += Value(300);
-
   return safety;
 }