Tweak single queen endgame scaling.

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 8b4a27bc112b3cad6d9997b3ea11209a5445edce..615df1bacd1a194510930306a29a85fad7e3a00d 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -127,23 +127,23 @@ namespace {
   };
 
   // Assorted bonuses and penalties
-  constexpr Score BishopPawns         = S(  3,  7);
+  constexpr Score BishopKingProtector = S(  6,  9);
   constexpr Score BishopOnKingRing    = S( 24,  0);
+  constexpr Score BishopOutpost       = S( 30, 23);
+  constexpr Score BishopPawns         = S(  3,  7);
   constexpr Score BishopXRayPawns     = S(  4,  5);
   constexpr Score CorneredBishop      = S( 50, 50);
   constexpr Score FlankAttacks        = S(  8,  0);
   constexpr Score Hanging             = S( 69, 36);
-  constexpr Score BishopKingProtector = S(  6,  9);
   constexpr Score KnightKingProtector = S(  8,  9);
   constexpr Score KnightOnQueen       = S( 16, 11);
+  constexpr Score KnightOutpost       = S( 56, 36);
   constexpr Score LongDiagonalBishop  = S( 45,  0);
   constexpr Score MinorBehindPawn     = S( 18,  3);
-  constexpr Score KnightOutpost       = S( 56, 36);
-  constexpr Score BishopOutpost       = S( 30, 23);
-  constexpr Score ReachableOutpost    = S( 31, 22);
   constexpr Score PassedFile          = S( 11,  8);
   constexpr Score PawnlessFlank       = S( 17, 95);
   constexpr Score QueenInfiltration   = S( -2, 14);
+  constexpr Score ReachableOutpost    = S( 31, 22);
   constexpr Score RestrictedPiece     = S(  7,  7);
   constexpr Score RookOnKingRing      = S( 16,  0);
   constexpr Score RookOnQueenFile     = S(  6, 11);
@@ -152,8 +152,9 @@ namespace {
   constexpr Score ThreatByPawnPush    = S( 48, 39);
   constexpr Score ThreatBySafePawn    = S(173, 94);
   constexpr Score TrappedRook         = S( 55, 13);
-  constexpr Score WeakQueen           = S( 56, 15);
   constexpr Score WeakQueenProtection = S( 14,  0);
+  constexpr Score WeakQueen           = S( 56, 15);
+
 
 #undef S
 
@@ -216,6 +217,7 @@ namespace {
 
   // Evaluation::initialize() computes king and pawn attacks, and the king ring
   // bitboard for a given color. This is done at the beginning of the evaluation.
+
   template<Tracing T> template<Color Us>
   void Evaluation<T>::initialize() {
 
@@ -255,6 +257,7 @@ namespace {
 
 
   // Evaluation::pieces() scores pieces of a given color and type
+
   template<Tracing T> template<Color Us, PieceType Pt>
   Score Evaluation<T>::pieces() {
 
@@ -377,7 +380,7 @@ namespace {
 
             // Bonus for queen on weak square in enemy camp
             if (relative_rank(Us, s) > RANK_4 && (~pe->pawn_attacks_span(Them) & s))
-                score += QueenInfiltration;    
+                score += QueenInfiltration;
         }
     }
     if (T)
@@ -388,6 +391,7 @@ namespace {
 
 
   // Evaluation::king() assigns bonuses and penalties to a king of a given color
+
   template<Tracing T> template<Color Us>
   Score Evaluation<T>::king() const {
 
@@ -496,6 +500,7 @@ namespace {
 
   // Evaluation::threats() assigns bonuses according to the types of the
   // attacking and the attacked pieces.
+
   template<Tracing T> template<Color Us>
   Score Evaluation<T>::threats() const {
 
@@ -721,8 +726,8 @@ namespace {
 
 
   // Evaluation::winnable() adjusts the mg and eg score components based on the
-  // known attacking/defending status of the players.
-  // A single value is derived from the mg and eg values and returned.
+  // known attacking/defending status of the players. A single value is derived
+  // by interpolation from the mg and eg values and returned.
 
   template<Tracing T>
   Value Evaluation<T>::winnable(Score score) const {
@@ -762,7 +767,6 @@ namespace {
     eg += v;
 
     // Compute the scale factor for the winning side
-
     Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK;
     int sf = me->scale_factor(pos, strongSide);
 
@@ -777,6 +781,16 @@ namespace {
             else
                 sf = 22 + 3 * pos.count<ALL_PIECES>(strongSide);
         }
+        else if (  pos.non_pawn_material(WHITE) == RookValueMg
+                && pos.non_pawn_material(BLACK) == RookValueMg
+                && !pe->passed_pawns(strongSide)
+                && pos.count<PAWN>(strongSide) - pos.count<PAWN>(~strongSide) <= 1
+                && bool(KingSide & pos.pieces(strongSide, PAWN)) != bool(QueenSide & pos.pieces(strongSide, PAWN))
+                && (attacks_bb<KING>(pos.square<KING>(~strongSide)) & pos.pieces(~strongSide, PAWN)))
+            sf = 36;
+        else if (pos.count<QUEEN>() == 1)
+            sf = 37 + 3 * (pos.count<QUEEN>(WHITE) == 1 ? pos.count<BISHOP>(BLACK) + pos.count<KNIGHT>(BLACK)
+                                                        : pos.count<BISHOP>(WHITE) + pos.count<KNIGHT>(WHITE));
         else
             sf = std::min(sf, 36 + 7 * pos.count<PAWN>(strongSide));
     }
@@ -828,12 +842,11 @@ namespace {
        return pos.side_to_move() == WHITE ? v : -v;
 
     // Main evaluation begins here
-
     initialize<WHITE>();
     initialize<BLACK>();
 
     // Pieces evaluated first (also populates attackedBy, attackedBy2).
-    // Note that the order of evaluation of the terms is left unspecified
+    // Note that the order of evaluation of the terms is left unspecified.
     score +=  pieces<WHITE, KNIGHT>() - pieces<BLACK, KNIGHT>()
             + pieces<WHITE, BISHOP>() - pieces<BLACK, BISHOP>()
             + pieces<WHITE, ROOK  >() - pieces<BLACK, ROOK  >()