Blocked pawn storm

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index 5c33577445dc22e6e1e8a69c4ae9a081e6b77f22..42819e142e5e7b12e2f7ad2c4a6159ab71962cd3 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -164,9 +164,6 @@ namespace {
                     e->passedPawns[Us] |= s;
         }
 
-        if (e->passedPawns[Us] & s)
-            e->asymmetry++;
-
         // Score this pawn
         if (supported | phalanx)
             score += Connected[opposed][bool(phalanx)][popcount(supported)][relative_rank(Us, s)];
@@ -223,11 +220,11 @@ Entry* probe(const Position& pos) {
       return e;
 
   e->key = key;
-  e->asymmetry = 0;
   e->scores[WHITE] = evaluate<WHITE>(pos, e);
   e->scores[BLACK] = evaluate<BLACK>(pos, e);
-  e->asymmetry += popcount(e->semiopenFiles[WHITE] ^ e->semiopenFiles[BLACK]);
-  e->openFiles  = popcount(e->semiopenFiles[WHITE] & e->semiopenFiles[BLACK]);
+  e->openFiles = popcount(e->semiopenFiles[WHITE] & e->semiopenFiles[BLACK]);
+  e->asymmetry = popcount(  (e->passedPawns[WHITE]   | e->passedPawns[BLACK])
+                          | (e->semiopenFiles[WHITE] ^ e->semiopenFiles[BLACK]));
 
   return e;
 }
@@ -240,14 +237,20 @@ template<Color Us>
 Value Entry::shelter_storm(const Position& pos, Square ksq) {
 
   const Color Them = (Us == WHITE ? BLACK : WHITE);
+  const Bitboard ShelterMask = (Us == WHITE ? 1ULL << SQ_A2 | 1ULL << SQ_B3 | 1ULL << SQ_C2 | 1ULL << SQ_F2 | 1ULL << SQ_G3 | 1ULL << SQ_H2
+                                            : 1ULL << SQ_A7 | 1ULL << SQ_B6 | 1ULL << SQ_C7 | 1ULL << SQ_F7 | 1ULL << SQ_G6 | 1ULL << SQ_H7);
+  const Bitboard StormMask   = (Us == WHITE ? 1ULL << SQ_A3 | 1ULL << SQ_C3 | 1ULL << SQ_F3 | 1ULL << SQ_H3
+                                            : 1ULL << SQ_A6 | 1ULL << SQ_C6 | 1ULL << SQ_F6 | 1ULL << SQ_H6);
 
   enum { BlockedByKing, Unopposed, BlockedByPawn, Unblocked };
 
-  Bitboard b = pos.pieces(PAWN) & (forward_ranks_bb(Us, ksq) | rank_bb(ksq));
+  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 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)
   {
@@ -266,6 +269,9 @@ Value Entry::shelter_storm(const Position& pos, Square ksq) {
                  [d][rkThem];
   }
 
+  if (popcount((ourPawns & ShelterMask) | (theirPawns & StormMask)) == 5)
+      safety += Value(300);
+
   return safety;
 }