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

   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 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
+  // Pawn penalties
-  const Score Isolated = S(13, 18);
+  constexpr Score Backward = S( 9, 24);
-  // Backward pawn penalty
+  constexpr Score Doubled  = S(11, 56);
-  const Score Backward = S(24, 12);
+  constexpr Score Isolated = S( 5, 15);
   // Connected pawn bonus by opposed, phalanx, #support and rank
   Score Connected[2][2][3][RANK_NB];
-  // Doubled pawn penalty
-  const Score Doubled = S(18, 38);
-  // Weakness of our pawn shelter in front of the king by [isKingFile][distance from edge][rank].
+  // Strength of pawn shelter for our king by [distance from edge][rank].
-  // RANK_1 = 0 is used for files where we have no pawns or our pawn is behind our king.
+  // RANK_1 = 0 is used for files where we have no pawn, or pawn is behind our king.
-  const Value ShelterWeakness[][int(FILE_NB) / 2][RANK_NB] = {
+  constexpr Value ShelterStrength[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(106), V( 6), V(33), V(86), V( 87), V(104), V(112) },
-      { V(101), V( 2), V(65), V(98), V( 58), V( 89), V(115) },
+    { V( -6), V( 81), V( 93), V( 58), V( 39), V( 18), V(  25) },
-      { 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(-43), V( 61), V( 35), V(-49), V(-29), V(-11), V( -63) },
-      { V(120), V(25), V(65), V(91), V( 66), V( 78), V(117) },
+    { V(-10), V( 75), V( 23), V( -2), V( 32), V(  3), V( -45) },
-      { V( 81), V( 2), V(47), V(63), V( 94), V( 93), V(104) } }
+    { V(-39), V(-13), V(-29), V(-52), V(-48), V(-67), V(-166) }
   };
-  // Danger of enemy pawns moving toward our king by [type][distance from edge][rank].
+  // Danger of enemy pawns moving toward our king by [distance from edge][rank].
-  // For the unopposed and unblocked cases, RANK_1 = 0 is used when opponent has
+  // RANK_1 = 0 is used for files where the enemy has no pawn, or their pawn
-  // no pawn on the given file, or their pawn is behind our king.
+  // is behind our king.
-  const Value StormDanger[][4][RANK_NB] = {
+  constexpr Value UnblockedStorm[int(FILE_NB) / 2][RANK_NB] = {
-    { { V( 0),  V(-290), V(-274), V(57), V(41) },  // BlockedByKing
-      { V( 0),  V(  60), V( 144), V(39), V(13) },
-      { V( 0),  V(  65), V( 141), V(41), V(34) },
-      { V( 0),  V(  53), V( 127), V(56), V(14) } },
+    { V( 89), V(107), V(123), V(93), V(57), V( 45), V( 51) },
-    { { V( 4),  V(  73), V( 132), V(46), V(31) },  // Unopposed
+    { V( 44), V(-18), V(123), V(46), V(39), V( -7), V( 23) },
-      { 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(  4), V( 52), V(162), V(37), V( 7), V(-14), V( -2) },
-    { { 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(22),  V(  45), V( 104), V(62), V( 6) },  // Unblocked
+    { V(-10), V(-14), V( 90), V(15), V( 2), V( -7), V(-16) }
-      { V(31),  V(  30), V(  99), V(39), V(19) },
-      { V(23),  V(  29), V(  96), V(41), V(15) },
-      { 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 S
   #undef V
   template<Color Us>
   Score evaluate(const Position& pos, Pawns::Entry* e) {
-    const Color     Them  = (Us == WHITE ? BLACK      : WHITE);
+    constexpr Color     Them = (Us == WHITE ? BLACK : WHITE);
-    const Direction Up    = (Us == WHITE ? NORTH      : SOUTH);
+    constexpr Direction Up   = (Us == WHITE ? NORTH : SOUTH);
-    const Direction Right = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
-    const Direction Left  = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
     Bitboard b, neighbours, stoppers, doubled, supported, phalanx;
     Bitboard lever, leverPush;
     Square s;
     bool opposed, backward;
     Bitboard theirPawns = pos.pieces(Them, PAWN);
     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->pawnAttacks[Us]   = pawn_attacks_bb<Us>(ourPawns);
     e->pawnsOnSquares[Us][BLACK] = popcount(ourPawns & DarkSquares);
     e->pawnsOnSquares[Us][WHITE] = pos.count<PAWN>(Us) - e->pawnsOnSquares[Us][BLACK];
     // Loop through all pawns of the current color and score each pawn
     while ((s = *pl++) != SQ_NONE)
         doubled    = ourPawns   & (s - Up);
         neighbours = ourPawns   & adjacent_files_bb(f);
         phalanx    = neighbours & rank_bb(s);
         supported  = neighbours & rank_bb(s - Up);
-        // A pawn is backward when it is behind all pawns of the same color on the
+        // A pawn is backward when it is behind all pawns of the same color
-        // adjacent files and cannot be safely advanced.
+        // on the adjacent files and cannot be safely advanced.
-        if (!neighbours || lever || relative_rank(Us, s) >= RANK_5)
+        backward =  !(ourPawns & pawn_attack_span(Them, s + Up))
-            backward = false;
-        else
-        {
-            // Find the backmost rank with neighbours or stoppers
-            b = rank_bb(backmost_sq(Us, neighbours | stoppers));
+                  && (stoppers & (leverPush | (s + Up)));
-            // 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 && (forward_ranks_bb(Them, s + Up) & neighbours)));
-        }
         // Passed pawns will be properly scored in evaluation because we need
         // 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)
-            && !(ourPawns & forward_file_bb(Us, s))
-            && popcount(supported) >= popcount(lever)
+            && popcount(supported) >= popcount(lever) - 1
             && popcount(phalanx)   >= popcount(leverPush))
             e->passedPawns[Us] |= s;
         else if (   stoppers == SquareBB[s + Up]
                  && relative_rank(Us, s) >= RANK_5)
 /// 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, 13, 24, 18, 76, 100, 175, 330 };
+  static constexpr int Seed[RANK_NB] = { 0, 13, 24, 18, 65, 100, 175, 330 };
   for (int opposed = 0; opposed <= 1; ++opposed)
       for (int phalanx = 0; phalanx <= 1; ++phalanx)
           for (int support = 0; support <= 2; ++support)
               for (Rank r = RANK_2; r < RANK_8; ++r)
   if (e->key == key)
       return e;
   e->key = key;
-  e->score = evaluate<WHITE>(pos, e) - evaluate<BLACK>(pos, e);
+  e->scores[WHITE] = evaluate<WHITE>(pos, e);
-  e->asymmetry = popcount(e->semiopenFiles[WHITE] ^ e->semiopenFiles[BLACK]);
+  e->scores[BLACK] = evaluate<BLACK>(pos, e);
   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;
+}
-/// Entry::shelter_storm() calculates shelter and storm penalties for the file
+/// Entry::evaluate_shelter() calculates the shelter bonus and the storm
-/// the king is on, as well as the two closest files.
+/// penalty for a king, looking at the king file and the two closest files.
 template<Color Us>
-Value Entry::shelter_storm(const Position& pos, Square ksq) {
+Value Entry::evaluate_shelter(const Position& pos, Square ksq) {
-  const Color Them = (Us == WHITE ? BLACK : WHITE);
+  constexpr Color     Them = (Us == WHITE ? BLACK : WHITE);
+  constexpr Direction Down = (Us == WHITE ? SOUTH : NORTH);
+  constexpr Bitboard  BlockRanks = (Us == WHITE ? Rank1BB | Rank2BB : Rank8BB | Rank7BB);
-  enum { BlockedByKing, Unopposed, BlockedByPawn, Unblocked };
-  Bitboard b = pos.pieces(PAWN) & (forward_ranks_bb(Us, ksq) | rank_bb(ksq));
+  Bitboard b = pos.pieces(PAWN) & ~forward_ranks_bb(Them, 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)));
+  Value safety = (shift<Down>(theirPawns) & (FileABB | FileHBB) & BlockRanks & ksq) ?
+                 Value(374) : Value(5);
+  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);
-      Rank rkUs = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1;
+      int ourRank = b ? relative_rank(Us, backmost_sq(Us, b)) : 0;
       b = theirPawns & file_bb(f);
-      Rank rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;
+      int theirRank = b ? relative_rank(Us, frontmost_sq(Them, b)) : 0;
       int d = std::min(f, ~f);
-      safety -=  ShelterWeakness[f == file_of(ksq)][d][rkUs]
+      safety += ShelterStrength[d][ourRank];
-               + StormDanger
-                 [f == file_of(ksq) && rkThem == relative_rank(Us, ksq) + 1 ? BlockedByKing  :
-                  rkUs   == RANK_1                                          ? Unopposed :
+      safety -= (ourRank && (ourRank == theirRank - 1)) ? 66 * (theirRank == RANK_3)
-                  rkThem == rkUs + 1                                        ? BlockedByPawn  : Unblocked]
+                                                        : UnblockedStorm[d][theirRank];
-                 [d][rkThem];
+  }
   return safety;
+}
 /// Entry::do_king_safety() calculates a bonus for king safety. It is called only
 /// when king square changes, which is about 20% of total king_safety() calls.
 template<Color Us>
-Score Entry::do_king_safety(const Position& pos, Square ksq) {
+Score Entry::do_king_safety(const Position& pos) {
+  Square ksq = pos.square<KING>(Us);
   kingSquares[Us] = ksq;
   castlingRights[Us] = pos.can_castle(Us);
   int minKingPawnDistance = 0;
   Bitboard pawns = pos.pieces(Us, PAWN);
   if (pawns)
-      while (!(DistanceRingBB[ksq][minKingPawnDistance++] & pawns)) {}
+      while (!(DistanceRingBB[ksq][++minKingPawnDistance] & pawns)) {}
-  Value bonus = shelter_storm<Us>(pos, ksq);
+  Value bonus = evaluate_shelter<Us>(pos, ksq);
   // If we can castle use the bonus after the castling if it is bigger
-  if (pos.can_castle(MakeCastling<Us, KING_SIDE>::right))
+  if (pos.can_castle(Us | KING_SIDE))
-      bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_G1)));
+      bonus = std::max(bonus, evaluate_shelter<Us>(pos, relative_square(Us, SQ_G1)));
-  if (pos.can_castle(MakeCastling<Us, QUEEN_SIDE>::right))
+  if (pos.can_castle(Us | QUEEN_SIDE))
-      bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_C1)));
+      bonus = std::max(bonus, evaluate_shelter<Us>(pos, relative_square(Us, SQ_C1)));
   return make_score(bonus, -16 * minKingPawnDistance);
+}
 // Explicit template instantiation
-template Score Entry::do_king_safety<WHITE>(const Position& pos, Square ksq);
+template Score Entry::do_king_safety<WHITE>(const Position& pos);
-template Score Entry::do_king_safety<BLACK>(const Position& pos, Square ksq);
+template Score Entry::do_king_safety<BLACK>(const Position& pos);
 } // namespace Pawns

Subversion Repositories Games.Chess Giants

Games.Chess Giants/engine-stockfish/pawns.cpp – Rev 169 → 185