Reset search time as early as possible

[stockfish] / src / pawns.cpp

diff --git a/src/pawns.cpp b/src/pawns.cpp
index d000209fec7ccdbdb3fc9929f0016b43ec5ed535..680ff198918ecc6c49471d64dff483d77f12d67f 100644 (file)
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -26,6 +26,7 @@
 
 namespace {
 
+  #define V Value
   #define S(mg, eg) make_score(mg, eg)
 
   // Doubled pawn penalty by opposed flag and file
@@ -63,7 +64,22 @@ namespace {
 
   const Score PawnStructureWeight = S(233, 201);
 
+  // Weakness of our pawn shelter in front of the king indexed by [king pawn][rank]
+  const Value ShelterWeakness[2][8] =
+  { { V(141), V(0), V(38), V(102), V(128), V(141), V(141) },
+    { V( 61), V(0), V(16), V( 44), V( 56), V( 61), V( 61) } };
+
+  // Danger of enemy pawns moving toward our king indexed by [pawn blocked][rank]
+  const Value StormDanger[2][8] =
+  { { V(26), V(0), V(128), V(51), V(26) },
+    { V(13), V(0), V( 64), V(25), V(13) } };
+
+  // Max bonus for king safety. Corresponds to start position with all the pawns
+  // in front of the king and no enemy pawn on the horizont.
+  const Value MaxSafetyBonus = V(263);
+
   #undef S
+  #undef V
 
   inline Score apply_weight(Score v, Score w) {
     return make_score((int(mg_value(v)) * mg_value(w)) / 0x100,
@@ -188,7 +204,7 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
       // full attack info to evaluate passed pawns. Only the frontmost passed
       // pawn on each file is considered a true passed pawn.
       if (passed && !doubled)
-          set_bit(&(pi->passedPawns[Us]), s);
+          pi->passedPawns[Us] |= s;
 
       // Score this pawn
       if (isolated)
@@ -210,31 +226,63 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
 }
 
 
-/// PawnInfo::updateShelter() calculates and caches king shelter. It is called
-/// only when king square changes, about 20% of total king_shelter() calls.
+/// PawnInfo::shelter_storm() calculates shelter and storm penalties for the file
+/// the king is on, as well as the two adjacent files.
+
 template<Color Us>
-Score PawnInfo::updateShelter(const Position& pos, Square ksq) {
+Value PawnInfo::shelter_storm(const Position& pos, Square ksq) {
+
+  const Color Them = (Us == WHITE ? BLACK : WHITE);
 
-  const int Shift = (Us == WHITE ? 8 : -8);
+  Value safety = MaxSafetyBonus;
+  Bitboard b = pos.pieces(PAWN) & (in_front_bb(Us, ksq) | rank_bb(ksq));
+  Bitboard ourPawns = b & pos.pieces(Us) & ~rank_bb(ksq);
+  Bitboard theirPawns = b & pos.pieces(Them);
+  Rank rkUs, rkThem;
+  File kf = file_of(ksq);
 
-  Bitboard pawns;
-  int r, shelter = 0;
+  kf = (kf == FILE_A) ? kf++ : (kf == FILE_H) ? kf-- : kf;
 
-  if (relative_rank(Us, ksq) <= RANK_4)
+  for (int f = kf - 1; f <= kf + 1; f++)
   {
-      pawns = pos.pieces(PAWN, Us) & this_and_adjacent_files_bb(file_of(ksq));
-      r = ksq & (7 << 3);
-      for (int i = 0; i < 3; i++)
-      {
-          r += Shift;
-          shelter += BitCount8Bit[(pawns >> r) & 0xFF] << (6 - i);
-      }
+      // Shelter penalty is higher for the pawn in front of the king
+      b = ourPawns & FileBB[f];
+      rkUs = b ? rank_of(Us == WHITE ? first_1(b) : ~last_1(b)) : RANK_1;
+      safety -= ShelterWeakness[f != kf][rkUs];
+
+      // Storm danger is smaller if enemy pawn is blocked
+      b  = theirPawns & FileBB[f];
+      rkThem = b ? rank_of(Us == WHITE ? first_1(b) : ~last_1(b)) : RANK_1;
+      safety -= StormDanger[rkThem == rkUs + 1][rkThem];
   }
+
+  return safety;
+}
+
+
+/// PawnInfo::update_safety() calculates and caches a bonus for king safety. It is
+/// called only when king square changes, about 20% of total king_safety() calls.
+
+template<Color Us>
+Score PawnInfo::update_safety(const Position& pos, Square ksq) {
+
   kingSquares[Us] = ksq;
-  kingShelters[Us] = make_score(shelter, 0);
-  return kingShelters[Us];
+
+  if (relative_rank(Us, ksq) > RANK_4)
+      return kingShelters[Us] = SCORE_ZERO;
+
+  Value bonus = shelter_storm<Us>(pos, ksq);
+
+  // If we can castle use the bonus after the castle if is bigger
+  if (pos.can_castle(Us == WHITE ? WHITE_OO : BLACK_OO))
+      bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_G1)));
+
+  if (pos.can_castle(Us == WHITE ? WHITE_OOO : BLACK_OOO))
+      bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_C1)));
+
+  return kingShelters[Us] = make_score(bonus, 0);
 }
 
 // Explicit template instantiation
-template Score PawnInfo::updateShelter<WHITE>(const Position& pos, Square ksq);
-template Score PawnInfo::updateShelter<BLACK>(const Position& pos, Square ksq);
+template Score PawnInfo::update_safety<WHITE>(const Position& pos, Square ksq);
+template Score PawnInfo::update_safety<BLACK>(const Position& pos, Square ksq);