simplified and increased threshold to switch between NNUE and classical

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index f43c62d687118d812761fc7e992b0ee2639243a3..1ae6cb3ac56f88d91ca8d56be259505d2a5f35e5 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -107,9 +107,10 @@ using namespace Trace;
 namespace {
 
   // Threshold for lazy and space evaluation
-  constexpr Value LazyThreshold1  = Value(1400);
-  constexpr Value LazyThreshold2  = Value(1300);
+  constexpr Value LazyThreshold1 =  Value(1400);
+  constexpr Value LazyThreshold2 =  Value(1300);
   constexpr Value SpaceThreshold = Value(12222);
+  constexpr Value NNUEThreshold  =   Value(520);
 
   // KingAttackWeights[PieceType] contains king attack weights by piece type
   constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 81, 52, 44, 10 };
@@ -180,7 +181,6 @@ namespace {
   constexpr Score MinorBehindPawn     = S( 18,  3);
   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);
@@ -345,7 +345,8 @@ namespace {
         {
             // Bonus if the piece is on an outpost square or can reach one
             // Reduced bonus for knights (BadOutpost) if few relevant targets
-            bb = OutpostRanks & attackedBy[Us][PAWN] & ~pe->pawn_attacks_span(Them);
+            bb = OutpostRanks & (attackedBy[Us][PAWN] | shift<Down>(pos.pieces(PAWN)))
+                              & ~pe->pawn_attacks_span(Them);
             Bitboard targets = pos.pieces(Them) & ~pos.pieces(PAWN);
 
             if (   Pt == KNIGHT
@@ -422,10 +423,6 @@ namespace {
             Bitboard queenPinners;
             if (pos.slider_blockers(pos.pieces(Them, ROOK, BISHOP), s, queenPinners))
                 score -= WeakQueen;
-
-            // Bonus for queen on weak square in enemy camp
-            if (relative_rank(Us, s) > RANK_4 && (~pe->pawn_attacks_span(Them) & s))
-                score += QueenInfiltration;
         }
     }
     if (T)
@@ -941,9 +938,13 @@ make_v:
 Value Eval::evaluate(const Position& pos) {
 
   if (Eval::useNNUE)
-      return NNUE::evaluate(pos);
-  else
-      return Evaluation<NO_TRACE>(pos).value();
+  {
+      Value v = eg_value(pos.psq_score());
+      // Take NNUE eval only on balanced positions
+      if (abs(v) < NNUEThreshold)
+         return NNUE::evaluate(pos) + Tempo;
+  }
+  return Evaluation<NO_TRACE>(pos).value();
 }
 
 /// trace() is like evaluate(), but instead of returning a value, it returns