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 1ae6cb3ac56f88d91ca8d56be259505d2a5f35e5..ce35c6306c42829db351da8051fd53d536d6aa9a 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -50,9 +50,13 @@ namespace Eval {
     std::string eval_file = std::string(Options["EvalFile"]);
     if (useNNUE && eval_file_loaded != eval_file)
     {
-        std::cerr << "Use of NNUE evaluation, but the file " << eval_file << " was not loaded successfully. "
-                  << "These network evaluation parameters must be available, compatible with this version of the code. "
-                  << "The UCI option EvalFile might need to specify the full path, including the directory/folder name, to the file." << std::endl;
+        UCI::OptionsMap defaults;
+        UCI::init(defaults);
+
+        std::cerr << "NNUE evaluation used, but the network file " << eval_file << " was not loaded successfully. "
+                  << "These network evaluation parameters must be available, and compatible with this version of the code. "
+                  << "The UCI option EvalFile might need to specify the full path, including the directory/folder name, to the file. "
+                  << "The default net can be downloaded from: https://tests.stockfishchess.org/api/nn/"+std::string(defaults["EvalFile"]) << std::endl;
         std::exit(EXIT_FAILURE);
     }
 
@@ -110,7 +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 };
@@ -941,7 +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();