WebSVN – Games.Chess Giants – Diff – /engine-stockfish/pawns.cpp

   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 namespace {
   #define V Value
   #define S(mg, eg) make_score(mg, eg)
-  // Isolated pawn penalty by opposed flag
+  // Isolated pawn penalty
-  const Score Isolated[2] = { S(45, 40), S(30, 27) };
+  const Score Isolated = S(13, 18);
-  // Backward pawn penalty by opposed flag
+  // Backward pawn penalty
-  const Score Backward[2] = { S(56, 33), S(41, 19) };
+  const Score Backward = S(24, 12);
-  // Unsupported pawn penalty for pawns which are neither isolated or backward
-  const Score Unsupported = S(17, 8);
-  // Connected pawn bonus by opposed, phalanx, twice supported and rank
+  // Connected pawn bonus by opposed, phalanx, #support and rank
-  Score Connected[2][2][2][RANK_NB];
+  Score Connected[2][2][3][RANK_NB];
   // Doubled pawn penalty
-  const Score Doubled = S(18,38);
+  const Score Doubled = S(18, 38);
-  // Lever bonus by rank
-  const Score Lever[RANK_NB] = {
-    S( 0,  0), S( 0,  0), S(0, 0), S(0, 0),
-    S(17, 16), S(33, 32), S(0, 0), S(0, 0)
-  };
-  // Weakness of our pawn shelter in front of the king by [distance from edge][rank]
+  // Weakness of our pawn shelter in front of the king by [isKingFile][distance from edge][rank].
+  // RANK_1 = 0 is used for files where we have no pawns or our pawn is behind our king.
-  const Value ShelterWeakness[][RANK_NB] = {
+  const Value ShelterWeakness[][int(FILE_NB) / 2][RANK_NB] = {
+    { { V( 97), V(17), V( 9), V(44), V( 84), V( 87), V( 99) }, // Not On King file
-    { V( 97), V(21), V(26), V(51), V(87), V( 89), V( 99) },
+      { V(106), V( 6), V(33), V(86), V( 87), V(104), V(112) },
-    { V(120), V( 0), V(28), V(76), V(88), V(103), V(104) },
+      { V(101), V( 2), V(65), V(98), V( 58), V( 89), V(115) },
-    { V(101), V( 7), V(54), V(78), V(77), V( 92), V(101) },
+      { V( 73), V( 7), V(54), V(73), V( 84), V( 83), V(111) } },
+    { { V(104), V(20), V( 6), V(27), V( 86), V( 93), V( 82) }, // On King file
+      { V(123), V( 9), V(34), V(96), V(112), V( 88), V( 75) },
+      { V(120), V(25), V(65), V(91), V( 66), V( 78), V(117) },
-    { V( 80), V(11), V(44), V(68), V(87), V( 90), V(119) }
+      { V( 81), V( 2), V(47), V(63), V( 94), V( 93), V(104) } }
   };
-  // Danger of enemy pawns moving toward our king by [type][distance from edge][rank]
+  // Danger of enemy pawns moving toward our king by [type][distance from edge][rank].
+  // For the unopposed and unblocked cases, RANK_1 = 0 is used when opponent has
+  // no pawn on the given file, or their pawn is behind our king.
   const Value StormDanger[][4][RANK_NB] = {
-    { { V( 0),  V(  67), V( 134), V(38), V(32) },
+    { { V( 0),  V(-290), V(-274), V(57), V(41) },  // BlockedByKing
-      { V( 0),  V(  57), V( 139), V(37), V(22) },
+      { V( 0),  V(  60), V( 144), V(39), V(13) },
-      { V( 0),  V(  43), V( 115), V(43), V(27) },
+      { V( 0),  V(  65), V( 141), V(41), V(34) },
-      { V( 0),  V(  68), V( 124), V(57), V(32) } },
+      { V( 0),  V(  53), V( 127), V(56), V(14) } },
-    { { V(20),  V(  43), V( 100), V(56), V(20) },
+    { { V( 4),  V(  73), V( 132), V(46), V(31) },  // Unopposed
-      { V(23),  V(  20), V(  98), V(40), V(15) },
+      { V( 1),  V(  64), V( 143), V(26), V(13) },
-      { V(23),  V(  39), V( 103), V(36), V(18) },
+      { V( 1),  V(  47), V( 110), V(44), V(24) },
-      { V(28),  V(  19), V( 108), V(42), V(26) } },
+      { V( 0),  V(  72), V( 127), V(50), V(31) } },
-    { { V( 0),  V(   0), V(  75), V(14), V( 2) },
+    { { V( 0),  V(   0), V(  79), V(23), V( 1) },  // BlockedByPawn
-      { V( 0),  V(   0), V( 150), V(30), V( 4) },
+      { V( 0),  V(   0), V( 148), V(27), V( 2) },
-      { V( 0),  V(   0), V( 160), V(22), V( 5) },
+      { V( 0),  V(   0), V( 161), V(16), V( 1) },
-      { V( 0),  V(   0), V( 166), V(24), V(13) } },
+      { V( 0),  V(   0), V( 171), V(22), V(15) } },
-    { { V( 0),  V(-283), V(-281), V(57), V(31) },
+    { { V(22),  V(  45), V( 104), V(62), V( 6) },  // Unblocked
-      { V( 0),  V(  58), V( 141), V(39), V(18) },
+      { V(31),  V(  30), V(  99), V(39), V(19) },
-      { V( 0),  V(  65), V( 142), V(48), V(32) },
+      { V(23),  V(  29), V(  96), V(41), V(15) },
-      { V( 0),  V(  60), V( 126), V(51), V(19) } }
+      { V(21),  V(  23), V( 116), V(41), V(15) } }
   };
   // Max bonus for king safety. Corresponds to start position with all the pawns
   // in front of the king and no enemy pawn on the horizon.
   const Value MaxSafetyBonus = V(258);
   #undef V
   template<Color Us>
   Score evaluate(const Position& pos, Pawns::Entry* e) {
-    const Color  Them  = (Us == WHITE ? BLACK      : WHITE);
+    const Color     Them  = (Us == WHITE ? BLACK      : WHITE);
-    const Square Up    = (Us == WHITE ? NORTH      : SOUTH);
+    const Direction Up    = (Us == WHITE ? NORTH      : SOUTH);
-    const Square Right = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
+    const Direction Right = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
-    const Square Left  = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
+    const Direction Left  = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
     Bitboard b, neighbours, stoppers, doubled, supported, phalanx;
+    Bitboard lever, leverPush;
     Square s;
-    bool opposed, lever, connected, backward;
+    bool opposed, backward;
     Score score = SCORE_ZERO;
     const Square* pl = pos.squares<PAWN>(Us);
-    const Bitboard* pawnAttacksBB = StepAttacksBB[make_piece(Us, PAWN)];
-    Bitboard ourPawns   = pos.pieces(Us  , PAWN);
+    Bitboard ourPawns   = pos.pieces(  Us, PAWN);
     Bitboard theirPawns = pos.pieces(Them, PAWN);
-    e->passedPawns[Us]   = e->pawnAttacksSpan[Us] = 0;
+    e->passedPawns[Us] = e->pawnAttacksSpan[Us] = e->weakUnopposed[Us] = 0;
     e->semiopenFiles[Us] = 0xFF;
     e->kingSquares[Us]   = SQ_NONE;
     e->pawnAttacks[Us]   = shift<Right>(ourPawns) | shift<Left>(ourPawns);
     e->pawnsOnSquares[Us][BLACK] = popcount(ourPawns & DarkSquares);
     e->pawnsOnSquares[Us][WHITE] = pos.count<PAWN>(Us) - e->pawnsOnSquares[Us][BLACK];
         e->semiopenFiles[Us]   &= ~(1 << f);
         e->pawnAttacksSpan[Us] |= pawn_attack_span(Us, s);
         // Flag the pawn
-        opposed    = theirPawns & forward_bb(Us, s);
+        opposed    = theirPawns & forward_file_bb(Us, s);
         stoppers   = theirPawns & passed_pawn_mask(Us, s);
-        lever      = theirPawns & pawnAttacksBB[s];
+        lever      = theirPawns & PawnAttacks[Us][s];
+        leverPush  = theirPawns & PawnAttacks[Us][s + Up];
-        doubled    = ourPawns   & (s + Up);
+        doubled    = ourPawns   & (s - Up);
         neighbours = ourPawns   & adjacent_files_bb(f);
         phalanx    = neighbours & rank_bb(s);
         supported  = neighbours & rank_bb(s - Up);
-        connected  = supported | phalanx;
         // A pawn is backward when it is behind all pawns of the same color on the
         // adjacent files and cannot be safely advanced.
         if (!neighbours || lever || relative_rank(Us, s) >= RANK_5)
             backward = false;
             // The pawn is backward when it cannot safely progress to that rank:
             // either there is a stopper in the way on this rank, or there is a
             // stopper on adjacent file which controls the way to that rank.
             backward = (b | shift<Up>(b & adjacent_files_bb(f))) & stoppers;
-            assert(!backward || !(pawn_attack_span(Them, s + Up) & neighbours));
+            assert(!(backward && (forward_ranks_bb(Them, s + Up) & neighbours)));
+        }
         // Passed pawns will be properly scored in evaluation because we need
-        // full attack info to evaluate them.
+        // full attack info to evaluate them. Include also not passed pawns
+        // which could become passed after one or two pawn pushes when are
+        // not attacked more times than defended.
+        if (   !(stoppers ^ lever ^ leverPush)
-        if (!stoppers && !(ourPawns & forward_bb(Us, s)))
+            && !(ourPawns & forward_file_bb(Us, s))
+            && popcount(supported) >= popcount(lever)
+            && popcount(phalanx)   >= popcount(leverPush))
             e->passedPawns[Us] |= s;
+        else if (   stoppers == SquareBB[s + Up]
+                 && relative_rank(Us, s) >= RANK_5)
+        {
+            b = shift<Up>(supported) & ~theirPawns;
+            while (b)
+                if (!more_than_one(theirPawns & PawnAttacks[Us][pop_lsb(&b)]))
+                    e->passedPawns[Us] |= s;
+        }
         // Score this pawn
+        if (supported | phalanx)
+            score += Connected[opposed][bool(phalanx)][popcount(supported)][relative_rank(Us, s)];
-        if (!neighbours)
+        else if (!neighbours)
-            score -= Isolated[opposed];
+            score -= Isolated, e->weakUnopposed[Us] += !opposed;
         else if (backward)
-            score -= Backward[opposed];
+            score -= Backward, e->weakUnopposed[Us] += !opposed;
-        else if (!supported)
+        if (doubled && !supported)
-            score -= Unsupported;
-        if (connected)
-            score += Connected[opposed][!!phalanx][more_than_one(supported)][relative_rank(Us, s)];
-        if (doubled)
             score -= Doubled;
-        if (lever)
-            score += Lever[relative_rank(Us, s)];
+    }
     return score;
+  }
 /// hard-coded tables, when makes sense, we prefer to calculate them with a formula
 /// to reduce independent parameters and to allow easier tuning and better insight.
 void init() {
-  static const int Seed[RANK_NB] = { 0, 8, 19, 13, 71, 94, 169, 324 };
+  static const int Seed[RANK_NB] = { 0, 13, 24, 18, 76, 100, 175, 330 };
   for (int opposed = 0; opposed <= 1; ++opposed)
       for (int phalanx = 0; phalanx <= 1; ++phalanx)
-          for (int apex = 0; apex <= 1; ++apex)
+          for (int support = 0; support <= 2; ++support)
               for (Rank r = RANK_2; r < RANK_8; ++r)
+  {
+      int v = 17 * support;
-      int v = (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed;
+      v += (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed;
-      v += (apex ? v / 2 : 0);
-      Connected[opposed][phalanx][apex][r] = make_score(v, v * 5 / 8);
+      Connected[opposed][phalanx][support][r] = make_score(v, v * (r - 2) / 4);
+  }
+}
 /// Pawns::probe() looks up the current position's pawns configuration in
   return e;
+}
 /// Entry::shelter_storm() calculates shelter and storm penalties for the file
-/// the king is on, as well as the two adjacent files.
+/// the king is on, as well as the two closest files.
 template<Color Us>
 Value Entry::shelter_storm(const Position& pos, Square ksq) {
   const Color Them = (Us == WHITE ? BLACK : WHITE);
-  enum { NoFriendlyPawn, Unblocked, BlockedByPawn, BlockedByKing };
+  enum { BlockedByKing, Unopposed, BlockedByPawn, Unblocked };
-  Bitboard b = pos.pieces(PAWN) & (in_front_bb(Us, rank_of(ksq)) | rank_bb(ksq));
+  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 = center - File(1); f <= center + File(1); ++f)
+  for (File f = File(center - 1); f <= File(center + 1); ++f)
+  {
       b = ourPawns & file_bb(f);
       Rank rkUs = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1;
-      b  = theirPawns & file_bb(f);
+      b = theirPawns & file_bb(f);
       Rank rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;
+      int d = std::min(f, ~f);
-      safety -=  ShelterWeakness[std::min(f, FILE_H - f)][rkUs]
+      safety -=  ShelterWeakness[f == file_of(ksq)][d][rkUs]
                + StormDanger
                  [f == file_of(ksq) && rkThem == relative_rank(Us, ksq) + 1 ? BlockedByKing  :
-                  rkUs   == RANK_1                                          ? NoFriendlyPawn :
+                  rkUs   == RANK_1                                          ? Unopposed :
                   rkThem == rkUs + 1                                        ? BlockedByPawn  : Unblocked]
-                 [std::min(f, FILE_H - f)][rkThem];
+                 [d][rkThem];
+  }
   return safety;
+}

Subversion Repositories Games.Chess Giants

Games.Chess Giants/engine-stockfish/pawns.cpp – Rev 154 → 169