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

 #include <algorithm>
 #include <cassert>
 #include "bitboard.h"
-#include "bitcount.h"
 #include "pawns.h"
 #include "position.h"
 #include "thread.h"
 namespace {
   #define V Value
   #define S(mg, eg) make_score(mg, eg)
-  // Isolated pawn penalty by opposed flag and file
+  // Isolated pawn penalty by opposed flag
-  const Score Isolated[2][FILE_NB] = {
-    { S(31, 36), S(45, 41), S(50, 41), S(50, 41),
-      S(50, 41), S(50, 41), S(45, 41), S(31, 36) },
+  const Score Isolated[2] = { S(45, 40), S(30, 27) };
-    { S(21, 24), S(30, 28), S(33, 28), S(33, 28),
-      S(33, 28), S(33, 28), S(30, 28), S(21, 24) } };
   // Backward pawn penalty by opposed flag
   const Score Backward[2] = { S(56, 33), S(41, 19) };
-  // Unsupported pawn penalty for pawns which are neither isolated or backward,
+  // Unsupported pawn penalty for pawns which are neither isolated or backward
-  // by number of pawns it supports [less than 2 / exactly 2].
-  const Score Unsupported[2] = { S(17, 8), S(21, 12) };
+  const Score Unsupported = S(17, 8);
   // Connected pawn bonus by opposed, phalanx, twice supported and rank
   Score Connected[2][2][2][RANK_NB];
-  // Doubled pawn penalty by file
+  // Doubled pawn penalty
-  const Score Doubled[FILE_NB] = {
+  const Score Doubled = S(18,38);
-    S(11, 34), S(17, 38), S(19, 38), S(19, 38),
-    S(19, 38), S(19, 38), S(17, 38), S(11, 34) };
   // 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) };
+    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]
   const Value ShelterWeakness[][RANK_NB] = {
     { V( 97), V(21), V(26), V(51), V(87), V( 89), V( 99) },
     { V(120), V( 0), V(28), V(76), V(88), V(103), V(104) },
     { V(101), V( 7), V(54), V(78), V(77), V( 92), V(101) },
-    { V( 80), V(11), V(44), V(68), V(87), V( 90), V(119) } };
+    { V( 80), V(11), V(44), V(68), V(87), V( 90), V(119) }
+  };
   // Danger of enemy pawns moving toward our king by [type][distance from edge][rank]
   const Value StormDanger[][4][RANK_NB] = {
     { { V( 0),  V(  67), V( 134), V(38), V(32) },
       { V( 0),  V(  57), V( 139), V(37), V(22) },
       { V( 0),  V(   0), V( 160), V(22), V( 5) },
       { V( 0),  V(   0), V( 166), V(24), V(13) } },
     { { V( 0),  V(-283), V(-281), V(57), V(31) },
       { V( 0),  V(  58), V( 141), V(39), V(18) },
       { V( 0),  V(  65), V( 142), V(48), V(32) },
-      { V( 0),  V(  60), V( 126), V(51), V(19) } } };
+      { V( 0),  V(  60), V( 126), V(51), V(19) } }
+  };
   // 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 ? DELTA_N  : DELTA_S);
+    const Square Up    = (Us == WHITE ? NORTH      : SOUTH);
-    const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW);
+    const Square Right = (Us == WHITE ? NORTH_EAST : SOUTH_WEST);
-    const Square Left  = (Us == WHITE ? DELTA_NW : DELTA_SE);
+    const Square Left  = (Us == WHITE ? NORTH_WEST : SOUTH_EAST);
-    Bitboard b, neighbours, doubled, supported, phalanx;
+    Bitboard b, neighbours, stoppers, doubled, supported, phalanx;
     Square s;
-    bool passed, isolated, opposed, backward, lever, connected;
+    bool opposed, lever, connected, 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 theirPawns = pos.pieces(Them, PAWN);
-    e->passedPawns[Us] = e->pawnAttacksSpan[Us] = 0;
+    e->passedPawns[Us]   = e->pawnAttacksSpan[Us] = 0;
-    e->kingSquares[Us] = SQ_NONE;
     e->semiopenFiles[Us] = 0xFF;
+    e->kingSquares[Us]   = SQ_NONE;
-    e->pawnAttacks[Us] = shift_bb<Right>(ourPawns) | shift_bb<Left>(ourPawns);
+    e->pawnAttacks[Us]   = shift<Right>(ourPawns) | shift<Left>(ourPawns);
-    e->pawnsOnSquares[Us][BLACK] = popcount<Max15>(ourPawns & DarkSquares);
+    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)
+    {
         assert(pos.piece_on(s) == make_piece(Us, PAWN));
         File f = file_of(s);
-        e->semiopenFiles[Us] &= ~(1 << f);
+        e->semiopenFiles[Us]   &= ~(1 << f);
         e->pawnAttacksSpan[Us] |= pawn_attack_span(Us, s);
         // Flag the pawn
-        neighbours  =   ourPawns   & adjacent_files_bb(f);
+        opposed    = theirPawns & forward_bb(Us, s);
-        doubled     =   ourPawns   & forward_bb(Us, s);
+        stoppers   = theirPawns & passed_pawn_mask(Us, s);
-        opposed     =   theirPawns & forward_bb(Us, s);
+        lever      = theirPawns & pawnAttacksBB[s];
-        passed      = !(theirPawns & passed_pawn_mask(Us, s));
+        doubled    = ourPawns   & (s + Up);
-        lever       =   theirPawns & pawnAttacksBB[s];
+        neighbours = ourPawns   & adjacent_files_bb(f);
-        phalanx     =   neighbours & rank_bb(s);
+        phalanx    = neighbours & rank_bb(s);
-        supported   =   neighbours & rank_bb(s - Up);
+        supported  = neighbours & rank_bb(s - Up);
-        connected   =   supported | phalanx;
+        connected  = supported | phalanx;
-        isolated    =  !neighbours;
-        // Test for backward pawn.
-        // If the pawn is passed, isolated, lever or connected it cannot be
-        // backward. If there are friendly pawns behind on adjacent files
+        // A pawn is backward when it is behind all pawns of the same color on the
-        // or if it is sufficiently advanced, it cannot be backward either.
+        // adjacent files and cannot be safely advanced.
-        if (   (passed | isolated | lever | connected)
-            || (ourPawns & pawn_attack_span(Them, s))
-            || (relative_rank(Us, s) >= RANK_5))
+        if (!neighbours || lever || relative_rank(Us, s) >= RANK_5)
             backward = false;
         else
+        {
-            // We now know there are no friendly pawns beside or behind this
-            // pawn on adjacent files. We now check whether the pawn is
-            // backward by looking in the forward direction on the adjacent
-            // files, and picking the closest pawn there.
+            // Find the backmost rank with neighbours or stoppers
-            b = pawn_attack_span(Us, s) & (ourPawns | theirPawns);
+            b = rank_bb(backmost_sq(Us, neighbours | stoppers));
-            b = pawn_attack_span(Us, s) & rank_bb(backmost_sq(Us, b));
+            // The pawn is backward when it cannot safely progress to that rank:
-            // If we have an enemy pawn in the same or next rank, the pawn is
+            // either there is a stopper in the way on this rank, or there is a
-            // backward because it cannot advance without being captured.
+            // stopper on adjacent file which controls the way to that rank.
-            backward = (b | shift_bb<Up>(b)) & theirPawns;
+            backward = (b | shift<Up>(b & adjacent_files_bb(f))) & stoppers;
-        }
-        assert(opposed | passed | (pawn_attack_span(Us, s) & theirPawns));
+            assert(!backward || !(pawn_attack_span(Them, s + Up) & neighbours));
+        }
         // Passed pawns will be properly scored in evaluation because we need
-        // full attack info to evaluate them. Only the frontmost passed
+        // full attack info to evaluate them.
-        // pawn on each file is considered a true passed pawn.
+        if (!stoppers && !(ourPawns & forward_bb(Us, s)))
-        if (passed && !doubled)
             e->passedPawns[Us] |= s;
         // Score this pawn
-        if (isolated)
+        if (!neighbours)
-            score -= Isolated[opposed][f];
+            score -= Isolated[opposed];
         else if (backward)
             score -= Backward[opposed];
         else if (!supported)
-            score -= Unsupported[more_than_one(neighbours & rank_bb(s + Up))];
+            score -= Unsupported;
         if (connected)
             score += Connected[opposed][!!phalanx][more_than_one(supported)][relative_rank(Us, s)];
         if (doubled)
-            score -= Doubled[f] / distance<Rank>(s, frontmost_sq(Us, doubled));
+            score -= Doubled;
         if (lever)
             score += Lever[relative_rank(Us, s)];
+    }
-    b = e->semiopenFiles[Us] ^ 0xFF;
-    e->pawnSpan[Us] = b ? int(msb(b) - lsb(b)) : 0;
     return score;
+  }
 } // namespace
 /// Pawns::init() initializes some tables needed by evaluation. Instead of using
 /// 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()
+void init() {
-{
   static const int Seed[RANK_NB] = { 0, 8, 19, 13, 71, 94, 169, 324 };
   for (int opposed = 0; opposed <= 1; ++opposed)
       for (int phalanx = 0; phalanx <= 1; ++phalanx)
           for (int apex = 0; apex <= 1; ++apex)
   if (e->key == key)
       return e;
   e->key = key;
   e->score = evaluate<WHITE>(pos, e) - evaluate<BLACK>(pos, e);
-  e->asymmetry = popcount<Max15>(e->semiopenFiles[WHITE] ^ e->semiopenFiles[BLACK]);
+  e->asymmetry = popcount(e->semiopenFiles[WHITE] ^ e->semiopenFiles[BLACK]);
+  e->openFiles = popcount(e->semiopenFiles[WHITE] & e->semiopenFiles[BLACK]);
   return e;
+}
 /// Entry::shelter_storm() calculates shelter and storm penalties for the file
   int minKingPawnDistance = 0;
   Bitboard pawns = pos.pieces(Us, PAWN);
   if (pawns)
       while (!(DistanceRingBB[ksq][minKingPawnDistance++] & pawns)) {}
-  if (relative_rank(Us, ksq) > RANK_4)
-      return make_score(0, -16 * minKingPawnDistance);
   Value bonus = shelter_storm<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))

Subversion Repositories Games.Chess Giants

Games.Chess Giants/engine-stockfish/pawns.cpp – Rev 96 → 154