Do not use lazy evaluation inside NNUE

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 04d41d5f6b0880d569aca2e14fe11811d66e2c54..40c41a8667add483ed8f4facd16dfb1e6e755e6b 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -216,9 +216,8 @@ namespace {
   // Threshold for lazy and space evaluation
   constexpr Value LazyThreshold1    =  Value(1565);
   constexpr Value LazyThreshold2    =  Value(1102);
-  constexpr Value LazyThresholdNNUE =  Value(1400);
   constexpr Value SpaceThreshold    = Value(11551);
-  constexpr Value NNUEThreshold1    =   Value(682);
+  constexpr Value NNUEThreshold1    =   Value(800);
   constexpr Value NNUEThreshold2    =   Value(176);
 
   // KingAttackWeights[PieceType] contains king attack weights by piece type
@@ -1120,7 +1119,7 @@ Value Eval::evaluate(const Position& pos) {
 
          int scale = 903 + 28 * pos.count<PAWN>() + 28 * pos.non_pawn_material() / 1024;
 
-         Value nnue = NNUE::evaluate(pos, true, LazyThresholdNNUE) * scale / 1024;
+         Value nnue = NNUE::evaluate(pos, true) * scale / 1024;
 
          if (pos.is_chess960())
              nnue += fix_FRC(pos);
@@ -1133,15 +1132,14 @@ Value Eval::evaluate(const Position& pos) {
       Value psq = Value(abs(eg_value(pos.psq_score())));
       int   r50 = 16 + pos.rule50_count();
       bool  largePsq = psq * 16 > (NNUEThreshold1 + pos.non_pawn_material() / 64) * r50;
-      bool  classical = largePsq;
 
       // Use classical evaluation for really low piece endgames.
       // One critical case is the draw for bishop + A/H file pawn vs naked king.
       bool lowPieceEndgame =   pos.non_pawn_material() == BishopValueMg
                             || (pos.non_pawn_material() < 2 * RookValueMg && pos.count<PAWN>() < 2);
 
-      v = classical || lowPieceEndgame ? Evaluation<NO_TRACE>(pos).value()
-                                       : adjusted_NNUE();
+      v = largePsq || lowPieceEndgame ? Evaluation<NO_TRACE>(pos).value()  // classical
+                                      : adjusted_NNUE();                   // NNUE
 
       // If the classical eval is small and imbalance large, use NNUE nevertheless.
       // For the case of opposite colored bishops, switch to NNUE eval with small