Adjust NNUE usage based on number of pawns in position

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index a642357e3c4904ea0ff5f6160325cd51d52b8b59..ce35c6306c42829db351da8051fd53d536d6aa9a 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -114,7 +114,7 @@ namespace {
   constexpr Value LazyThreshold1 =  Value(1400);
   constexpr Value LazyThreshold2 =  Value(1300);
   constexpr Value SpaceThreshold = Value(12222);
-  constexpr Value NNUEThreshold  =   Value(520);
+  constexpr Value NNUEThreshold  =   Value(460);
 
   // KingAttackWeights[PieceType] contains king attack weights by piece type
   constexpr int KingAttackWeights[PIECE_TYPE_NB] = { 0, 0, 81, 52, 44, 10 };
@@ -945,7 +945,7 @@ Value Eval::evaluate(const Position& pos) {
   {
       Value v = eg_value(pos.psq_score());
       // Take NNUE eval only on balanced positions
-      if (abs(v) < NNUEThreshold)
+      if (abs(v) < NNUEThreshold + 20 * pos.count<PAWN>())
          return NNUE::evaluate(pos) + Tempo;
   }
   return Evaluation<NO_TRACE>(pos).value();