Reformat Eval::evaluate()

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 58dd0026fdd1e94006b062b4ec3bb97ba4a6dcd1..2f1d5067d013ce2d0ffee3785aefe78910d689c1 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -61,7 +61,7 @@ namespace Stockfish {
 namespace Eval {
 
   bool useNNUE;
-  string eval_file_loaded = "None";
+  string currentEvalFileName = "None";
 
   /// NNUE::init() tries to load a NNUE network at startup time, or when the engine
   /// receives a UCI command "setoption name EvalFile value nn-[a-z0-9]{12}.nnue"
@@ -90,13 +90,13 @@ namespace Eval {
     #endif
 
     for (string directory : dirs)
-        if (eval_file_loaded != eval_file)
+        if (currentEvalFileName != eval_file)
         {
             if (directory != "<internal>")
             {
                 ifstream stream(directory + eval_file, ios::binary);
                 if (load_eval(eval_file, stream))
-                    eval_file_loaded = eval_file;
+                    currentEvalFileName = eval_file;
             }
 
             if (directory == "<internal>" && eval_file == EvalFileDefaultName)
@@ -111,7 +111,7 @@ namespace Eval {
 
                 istream stream(&buffer);
                 if (load_eval(eval_file, stream))
-                    eval_file_loaded = eval_file;
+                    currentEvalFileName = eval_file;
             }
         }
   }
@@ -123,7 +123,7 @@ namespace Eval {
     if (eval_file.empty())
         eval_file = EvalFileDefaultName;
 
-    if (useNNUE && eval_file_loaded != eval_file)
+    if (useNNUE && currentEvalFileName != eval_file)
     {
 
         string msg1 = "If the UCI option \"Use NNUE\" is set to true, network evaluation parameters compatible with the engine must be available.";
@@ -1081,33 +1081,22 @@ Value Eval::evaluate(const Position& pos) {
 
   Value v;
 
-  if (!Eval::useNNUE)
-      v = Evaluation<NO_TRACE>(pos).value();
+  // Deciding between classical and NNUE eval: for high PSQ imbalance we use classical,
+  // but we switch to NNUE during long shuffling or with high material on the board.
+
+  if (  !useNNUE
+      || abs(eg_value(pos.psq_score())) * 5 > (850 + pos.non_pawn_material() / 64) * (5 + pos.rule50_count()))
+      v = Evaluation<NO_TRACE>(pos).value();          // classical
   else
   {
-      // Scale and shift NNUE for compatibility with search and classical evaluation
-      auto  adjusted_NNUE = [&]()
-      {
-         int scale =   883
-                     + 32 * pos.count<PAWN>()
-                     + 32 * pos.non_pawn_material() / 1024;
-
-         Value nnue = NNUE::evaluate(pos, true) * scale / 1024;
-
-         if (pos.is_chess960())
-             nnue += fix_FRC(pos);
-
-         return nnue;
-      };
+      int scale =   883
+                  + 32 * pos.count<PAWN>()
+                  + 32 * pos.non_pawn_material() / 1024;
 
-      // If there is PSQ imbalance we use the classical eval, but we switch to
-      // NNUE eval faster when shuffling or if the material on the board is high.
-      int r50 = pos.rule50_count();
-      Value psq = Value(abs(eg_value(pos.psq_score())));
-      bool classical = psq * 5 > (850 + pos.non_pawn_material() / 64) * (5 + r50);
+       v = NNUE::evaluate(pos, true) * scale / 1024;  // NNUE
 
-      v = classical ? Evaluation<NO_TRACE>(pos).value()  // classical
-                    : adjusted_NNUE();                   // NNUE
+       if (pos.is_chess960())
+           v += fix_FRC(pos);
   }
 
   // Damp down the evaluation linearly when shuffling