Simplify WeakUnopposedPawn #2181

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 8c1b0b086d30d87f0a943756908d9f072462a3ae..0da6ba4ddfa2c4b91e4387a999181d2a949ebef5 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -141,7 +141,7 @@ namespace {
   constexpr Score KnightOnQueen      = S( 16, 12);
   constexpr Score LongDiagonalBishop = S( 45,  0);
   constexpr Score MinorBehindPawn    = S( 18,  3);
-  constexpr Score Outpost            = S(  9,  3);
+  constexpr Score Outpost            = S( 36, 12);
   constexpr Score PawnlessFlank      = S( 17, 95);
   constexpr Score RestrictedPiece    = S(  7,  7);
   constexpr Score RookOnPawn         = S( 10, 32);
@@ -152,7 +152,6 @@ namespace {
   constexpr Score ThreatBySafePawn   = S(173, 94);
   constexpr Score TrappedRook        = S( 47,  4);
   constexpr Score WeakQueen          = S( 49, 15);
-  constexpr Score WeakUnopposedPawn  = S( 12, 23);
 
 #undef S
 
@@ -305,14 +304,12 @@ namespace {
         if (Pt == BISHOP || Pt == KNIGHT)
         {
             // Bonus if piece is on an outpost square or can reach one
-            bb = OutpostRanks & ~pe->pawn_attacks_span(Them);
+            bb = OutpostRanks & attackedBy[Us][PAWN] & ~pe->pawn_attacks_span(Them);
             if (bb & s)
-                score += Outpost * (Pt == KNIGHT ? 4 : 2)
-                                 * ((attackedBy[Us][PAWN] & s) ? 2 : 1);
+                score += Outpost * (Pt == KNIGHT ? 2 : 1);
 
-            else if (bb &= b & ~pos.pieces(Us))
-                score += Outpost * (Pt == KNIGHT ? 2 : 1)
-                                 * ((attackedBy[Us][PAWN] & bb) ? 2 : 1);
+            else if (bb & b & ~pos.pieces(Us))
+                score += Outpost / (Pt == KNIGHT ? 1 : 2);
 
             // Knight and Bishop bonus for being right behind a pawn
             if (shift<Down>(pos.pieces(PAWN)) & s)
@@ -557,10 +554,6 @@ namespace {
 
     score += RestrictedPiece * popcount(b);
 
-    // Bonus for enemy unopposed weak pawns
-    if (pos.pieces(Us, ROOK, QUEEN))
-        score += WeakUnopposedPawn * pe->weak_unopposed(Them);
-
     // Find squares where our pawns can push on the next move
     b  = shift<Up>(pos.pieces(Us, PAWN)) & ~pos.pieces();
     b |= shift<Up>(b & TRank3BB) & ~pos.pieces();