Introduce bad outpost penalty

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index bb1724a4e3bf8dd86466778925cb19ad2b2caa68..ca6ea5c44fd6da373d4e1cf9bf10deca66d2771f 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -134,6 +134,7 @@ namespace {
   };
 
   // Assorted bonuses and penalties
+  constexpr Score BadOutpost          = S( -7, 36);
   constexpr Score BishopOnKingRing    = S( 24,  0);
   constexpr Score BishopPawns         = S(  3,  7);
   constexpr Score BishopXRayPawns     = S(  4,  5);
@@ -310,7 +311,13 @@ namespace {
         {
             // Bonus if piece is on an outpost square or can reach one
             bb = OutpostRanks & attackedBy[Us][PAWN] & ~pe->pawn_attacks_span(Them);
-            if (bb & s)
+            if (   Pt == KNIGHT
+                && bb & s & ~CenterFiles
+                && !(b & pos.pieces(Them) & ~pos.pieces(PAWN))
+                && !conditional_more_than_two(
+                      pos.pieces(Them) & ~pos.pieces(PAWN) & (s & QueenSide ? QueenSide : KingSide)))
+                score += BadOutpost;
+            else if (bb & s)
                 score += Outpost[Pt == BISHOP];
             else if (Pt == KNIGHT && bb & b & ~pos.pieces(Us))
                 score += ReachableOutpost;
@@ -719,9 +726,9 @@ 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
-  // by interpolation from the mg and eg values and returned.
+  // Evaluation::winnable() adjusts the midgame and endgame score components, based on
+  // the known attacking/defending status of the players. The final value is derived
+  // by interpolation from the midgame and endgame values.
 
   template<Tracing T>
   Value Evaluation<T>::winnable(Score score) const {
@@ -764,7 +771,7 @@ namespace {
     Color strongSide = eg > VALUE_DRAW ? WHITE : BLACK;
     int sf = me->scale_factor(pos, strongSide);
 
-    // If scale is not already specific, scale down the endgame via general heuristics
+    // If scale factor is not already specific, scale down via general heuristics
     if (sf == SCALE_FACTOR_NORMAL)
     {
         if (pos.opposite_bishops())
@@ -779,7 +786,7 @@ namespace {
                 && pos.non_pawn_material(BLACK) == RookValueMg
                 && 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)))
+                && (attackedBy[~strongSide][KING] & 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)