Re-introduce "keep pawns on both flanks"

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index ac8bde741a385650f9a8155025fbfd99f03c5746..4a4ae2ad982b430d941dbcaca85af66a0eb0bf12 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -162,7 +162,7 @@ namespace {
   constexpr Score HinderPassedPawn   = S(  8,  0);
   constexpr Score KingProtector      = S(  6,  6);
   constexpr Score KnightOnQueen      = S( 21, 11);
-  constexpr Score LongDiagonalBishop = S( 22,  0);
+  constexpr Score LongDiagonalBishop = S( 46,  0);
   constexpr Score MinorBehindPawn    = S( 16,  0);
   constexpr Score Overload           = S( 13,  6);
   constexpr Score PawnlessFlank      = S( 19, 84);
@@ -351,7 +351,7 @@ namespace {
                                      * (1 + popcount(blocked & CenterFiles));
 
                 // 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)))
+                if (more_than_one(attacks_bb<BISHOP>(s, pos.pieces(PAWN)) & Center))
                     score += LongDiagonalBishop;
             }
 
@@ -758,12 +758,16 @@ namespace {
     int outflanking =  distance<File>(pos.square<KING>(WHITE), pos.square<KING>(BLACK))
                      - distance<Rank>(pos.square<KING>(WHITE), pos.square<KING>(BLACK));
 
+    bool pawnsOnBothFlanks =   (pos.pieces(PAWN) & QueenSide)          
+                            && (pos.pieces(PAWN) & KingSide);
+
     // Compute the initiative bonus for the attacking side
     int complexity =   8 * pe->pawn_asymmetry()
                     + 12 * pos.count<PAWN>()
                     + 12 * outflanking
+                    + 16 * pawnsOnBothFlanks
                     + 48 * !pos.non_pawn_material()
-                    -110 ;
+                    -118 ;
 
     // Now apply the bonus: note that we find the attacking side by extracting
     // the sign of the endgame value, and that we carefully cap the bonus so