Simplify some kingring penalties expressions

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index f34c01b6c3e15cc8072e60d40c55c0f80626e964..39dac6d14ffb5481b74986ec41660cf5aebac6f0 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -31,11 +31,10 @@
 
 namespace {
 
-  const Bitboard LongDiagonals = 0x8142241818244281ULL; // A1..H8 | H1..A8
-  const Bitboard Center        = (FileDBB | FileEBB) & (Rank4BB | Rank5BB);
-  const Bitboard QueenSide     = FileABB | FileBBB | FileCBB | FileDBB;
-  const Bitboard CenterFiles   = FileCBB | FileDBB | FileEBB | FileFBB;
-  const Bitboard KingSide      = FileEBB | FileFBB | FileGBB | FileHBB;
+  const Bitboard Center      = (FileDBB | FileEBB) & (Rank4BB | Rank5BB);
+  const Bitboard QueenSide   = FileABB | FileBBB | FileCBB | FileDBB;
+  const Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB;
+  const Bitboard KingSide    = FileEBB | FileFBB | FileGBB | FileHBB;
 
   const Bitboard KingFlank[FILE_NB] = {
     QueenSide, QueenSide, QueenSide, CenterFiles, CenterFiles, KingSide, KingSide, KingSide
@@ -46,7 +45,7 @@ namespace {
     enum Tracing {NO_TRACE, TRACE};
 
     enum Term { // The first 8 entries are for PieceType
-      MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, TOTAL, TERM_NB
+      MATERIAL = 8, IMBALANCE, MOBILITY, THREAT, PASSED, SPACE, INITIATIVE, TOTAL, TERM_NB
     };
 
     double scores[TERM_NB][COLOR_NB][PHASE_NB];
@@ -64,7 +63,7 @@ namespace {
 
     std::ostream& operator<<(std::ostream& os, Term t) {
 
-      if (t == MATERIAL || t == IMBALANCE || t == Term(PAWN) || t == TOTAL)
+      if (t == MATERIAL || t == IMBALANCE || t == Term(PAWN) || t == INITIATIVE || t == TOTAL)
           os << "  ---   --- |   ---   --- | ";
       else
           os << std::setw(5) << scores[t][WHITE][MG] << " "
@@ -222,7 +221,7 @@ namespace {
   const Score CloseEnemies        = S(  7,  0);
   const Score PawnlessFlank       = S( 20, 80);
   const Score ThreatByHangingPawn = S( 71, 61);
-  const Score ThreatBySafePawn    = S(182,175);
+  const Score ThreatBySafePawn    = S(192,175);
   const Score ThreatByRank        = S( 16,  3);
   const Score Hanging             = S( 48, 27);
   const Score WeakUnopposedPawn   = S(  5, 25);
@@ -354,10 +353,8 @@ namespace {
                 // Penalty for pawns on the same color square as the bishop
                 score -= BishopPawns * pe->pawns_on_same_color_squares(Us, s);
 
-                // Bonus for bishop on a long diagonal without pawns in the center
-                if (    (LongDiagonals & s)
-                    && !(attackedBy[Them][PAWN] & s)
-                    && !(Center & PseudoAttacks[BISHOP][s] & pos.pieces(PAWN)))
+                // Bonus for bishop on a long diagonal which can "see" both center squares
+                if (more_than_one(Center & (attacks_bb<BISHOP>(s, pos.pieces(PAWN)) | s)))
                     score += LongRangedBishop;
             }
 
@@ -424,7 +421,7 @@ namespace {
                                        : AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB);
 
     const Square ksq = pos.square<KING>(Us);
-    Bitboard kingOnlyDefended, undefended, b, b1, b2, safe, other;
+    Bitboard weak, b, b1, b2, safe, other;
     int kingDanger;
 
     // King shelter and enemy pawns storm
@@ -433,16 +430,10 @@ namespace {
     // Main king safety evaluation
     if (kingAttackersCount[Them] > (1 - pos.count<QUEEN>(Them)))
     {
-        // Find the attacked squares which are defended only by our king...
-        kingOnlyDefended =   attackedBy[Them][ALL_PIECES]
-                          &  attackedBy[Us][KING]
-                          & ~attackedBy2[Us];
-
-        // ... and those which are not defended at all in the larger king ring
-        undefended =   attackedBy[Them][ALL_PIECES]
-                    & ~attackedBy[Us][ALL_PIECES]
-                    &  kingRing[Us]
-                    & ~pos.pieces(Them);
+        // Attacked squares defended at most once by our queen or king
+        weak =  attackedBy[Them][ALL_PIECES]
+              & ~attackedBy2[Us]
+              & (attackedBy[Us][KING] | attackedBy[Us][QUEEN] | ~attackedBy[Us][ALL_PIECES]);
 
         // Initialize the 'kingDanger' variable, which will be transformed
         // later into a king danger score. The initial value is based on the
@@ -451,7 +442,7 @@ namespace {
         // the quality of the pawn shelter (current 'score' value).
         kingDanger =        kingAttackersCount[Them] * kingAttackersWeight[Them]
                     + 102 * kingAdjacentZoneAttacksCount[Them]
-                    + 191 * popcount(kingOnlyDefended | undefended)
+                    + 191 * popcount(kingRing[Us] & weak)
                     + 143 * !!pos.pinned_pieces(Us)
                     - 848 * !pos.count<QUEEN>(Them)
                     -   9 * mg_value(score) / 8
@@ -459,21 +450,15 @@ namespace {
 
         // Analyse the safe enemy's checks which are possible on next move
         safe  = ~pos.pieces(Them);
-        safe &= ~attackedBy[Us][ALL_PIECES] | (kingOnlyDefended & attackedBy2[Them]);
+        safe &= ~attackedBy[Us][ALL_PIECES] | (weak & attackedBy2[Them]);
 
         b1 = pos.attacks_from<  ROOK>(ksq);
         b2 = pos.attacks_from<BISHOP>(ksq);
 
         // Enemy queen safe checks
-        if ((b1 | b2) & attackedBy[Them][QUEEN] & safe)
+        if ((b1 | b2) & attackedBy[Them][QUEEN] & safe & ~attackedBy[Us][QUEEN])
             kingDanger += QueenCheck;
 
-        // For minors and rooks, also consider the square safe if attacked twice,
-        // and only defended by our queen.
-        safe |=  attackedBy2[Them]
-               & ~(attackedBy2[Us] | pos.pieces(Them))
-               & attackedBy[Us][QUEEN];
-
         // Some other potential checks are also analysed, even from squares
         // currently occupied by the opponent own pieces, as long as the square
         // is not attacked by our pawns, and is not occupied by a blocked pawn.
@@ -778,6 +763,9 @@ namespace {
     // that the endgame score will never change sign after the bonus.
     int v = ((eg > 0) - (eg < 0)) * std::max(initiative, -abs(eg));
 
+    if (T)
+        Trace::add(INITIATIVE, make_score(0, v));
+
     return make_score(0, v);
   }
 
@@ -938,6 +926,7 @@ std::string Eval::trace(const Position& pos) {
      << "        Threats | " << Term(THREAT)
      << "   Passed pawns | " << Term(PASSED)
      << "          Space | " << Term(SPACE)
+     << "     Initiative | " << Term(INITIATIVE)
      << "----------------+-------------+-------------+-------------\n"
      << "          Total | " << Term(TOTAL);