Weak queen protection

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index be39f8a7b314019333a55cf27175fa2f3ac303a7..06366e09501608c59743cf82f0e0507c36636175 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -114,11 +114,11 @@ namespace {
   // which piece type attacks which one. Attacks on lesser pieces which are
   // pawn-defended are not considered.
   constexpr Score ThreatByMinor[PIECE_TYPE_NB] = {
-    S(0, 0), S(6, 32), S(59, 41), S(79, 56), S(90, 119), S(79, 161)
+    S(0, 0), S(5, 32), S(57, 41), S(77, 56), S(88, 119), S(79, 161)
   };
 
   constexpr Score ThreatByRook[PIECE_TYPE_NB] = {
-    S(0, 0), S(3, 44), S(38, 71), S(38, 61), S(0, 38), S(51, 38)
+    S(0, 0), S(2, 44), S(36, 71), S(36, 61), S(0, 38), S(51, 38)
   };
 
   // PassedRank[Rank] contains a bonus according to the rank of a passed pawn
@@ -139,13 +139,12 @@ namespace {
   constexpr Score PassedFile         = S( 11,  8);
   constexpr Score PawnlessFlank      = S( 17, 95);
   constexpr Score RestrictedPiece    = S(  7,  7);
-  constexpr Score ReachableOutpost   = S( 32, 10);
   constexpr Score RookOnQueenFile    = S(  7,  6);
   constexpr Score SliderOnQueen      = S( 59, 18);
   constexpr Score ThreatByKing       = S( 24, 89);
   constexpr Score ThreatByPawnPush   = S( 48, 39);
   constexpr Score ThreatBySafePawn   = S(173, 94);
-  constexpr Score TrappedRook        = S( 52, 30);
+  constexpr Score TrappedRook        = S( 52, 10);
   constexpr Score WeakQueen          = S( 49, 15);
 
 #undef S
@@ -168,7 +167,7 @@ namespace {
     template<Color Us> Score passed() const;
     template<Color Us> Score space() const;
     ScaleFactor scale_factor(Value eg) const;
-    Score initiative(Score score, Score materialScore) const;
+    Score initiative(Score score) const;
 
     const Position& pos;
     Material::Entry* me;
@@ -296,7 +295,7 @@ namespace {
                 score += Outpost * (Pt == KNIGHT ? 2 : 1);
 
             else if (Pt == KNIGHT && bb & b & ~pos.pieces(Us))
-                score += ReachableOutpost;
+                score += Outpost;
 
             // Knight and Bishop bonus for being right behind a pawn
             if (shift<Down>(pos.pieces(PAWN)) & s)
@@ -517,14 +516,16 @@ namespace {
         b =  ~attackedBy[Them][ALL_PIECES]
            | (nonPawnEnemies & attackedBy2[Us]);
         score += Hanging * popcount(weak & b);
+
+        // Additional bonus if weak piece is only protected by a queen
+        score += make_score(14, 0) * popcount(weak & attackedBy[Them][QUEEN]);
     }
 
     // Bonus for restricting their piece moves
-    // Greater bonus when landing square is occupied
     b =   attackedBy[Them][ALL_PIECES]
        & ~stronglyProtected
        &  attackedBy[Us][ALL_PIECES];
-    score += RestrictedPiece * (popcount(b) + popcount(b & pos.pieces()));
+    score += RestrictedPiece * popcount(b);
 
     // Protected or unattacked squares
     safe = ~attackedBy[Them][ALL_PIECES] | attackedBy[Us][ALL_PIECES];
@@ -696,14 +697,11 @@ namespace {
   // known attacking/defending status of the players.
 
   template<Tracing T>
-  Score Evaluation<T>::initiative(Score score, Score materialScore) const {
+  Score Evaluation<T>::initiative(Score score) const {
 
     int outflanking =  distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
                      - distance<Rank>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
 
-    bool infiltration =   rank_of(pos.square<KING>(WHITE)) > RANK_4
-                       || rank_of(pos.square<KING>(BLACK)) < RANK_5;
-
     bool pawnsOnBothFlanks =   (pos.pieces(PAWN) & QueenSide)
                             && (pos.pieces(PAWN) & KingSide);
 
@@ -711,18 +709,19 @@ namespace {
                            &&  outflanking < 0
                            && !pawnsOnBothFlanks;
 
+    bool infiltration = rank_of(pos.square<KING>(WHITE)) > RANK_4
+                     || rank_of(pos.square<KING>(BLACK)) < RANK_5;
+
     // Compute the initiative bonus for the attacking side
     int complexity =   9 * pe->passed_count()
                     + 11 * pos.count<PAWN>()
                     +  9 * outflanking
-                    + 12 * infiltration
                     + 21 * pawnsOnBothFlanks
+                    + 24 * infiltration
                     + 51 * !pos.non_pawn_material()
                     - 43 * almostUnwinnable
-                    - 100 ;
+                    -110 ;
 
-    // Give more importance to non-material score
-    score = (score * 2 - materialScore) / 2;
     Value mg = mg_value(score);
     Value eg = eg_value(score);
 
@@ -794,9 +793,6 @@ namespace {
     if (abs(v) > LazyThreshold + pos.non_pawn_material() / 64)
        return pos.side_to_move() == WHITE ? v : -v;
 
-    // Remember this score
-    Score materialScore = score;
-
     // Main evaluation begins here
 
     initialize<WHITE>();
@@ -815,7 +811,7 @@ namespace {
             + passed< WHITE>() - passed< BLACK>()
             + space<  WHITE>() - space<  BLACK>();
 
-    score += initiative(score, materialScore);
+    score += initiative(score);
 
     // Interpolate between a middlegame and a (scaled by 'sf') endgame score
     ScaleFactor sf = scale_factor(eg_value(score));