Add an UCI level command "export_net".

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 789e28594cd6d8f2a7c555750b165903088f1afd..f0784e8f915e113f414ba85e2496c9e7eab66156 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -33,6 +33,7 @@
 #include "misc.h"
 #include "pawns.h"
 #include "thread.h"
+#include "timeman.h"
 #include "uci.h"
 #include "incbin/incbin.h"
 
@@ -46,7 +47,9 @@
 // Note that this does not work in Microsoft Visual Studio.
 #if !defined(_MSC_VER) && !defined(NNUE_EMBEDDING_OFF)
   INCBIN(EmbeddedNNUE, EvalFileDefaultName);
+  constexpr bool             gHasEmbeddedNet = true;
 #else
+  constexpr bool             gHasEmbeddedNet = false;
   const unsigned char        gEmbeddedNNUEData[1] = {0x0};
   const unsigned char *const gEmbeddedNNUEEnd = &gEmbeddedNNUEData[1];
   const unsigned int         gEmbeddedNNUESize = 1;
@@ -113,6 +116,15 @@ namespace Eval {
         }
   }
 
+  void NNUE::export_net() {
+    if constexpr (gHasEmbeddedNet) {
+      ofstream stream(EvalFileDefaultName, std::ios_base::binary);
+      stream.write(reinterpret_cast<const char*>(gEmbeddedNNUEData), gEmbeddedNNUESize);
+    } else {
+      sync_cout << "No embedded network file." << sync_endl;
+    }
+  }
+
   /// NNUE::verify() verifies that the last net used was loaded successfully
   void NNUE::verify() {
 
@@ -1096,7 +1108,7 @@ Value Eval::evaluate(const Position& pos) {
                     + material / 32
                     - 4 * pos.rule50_count();
 
-         Value nnue = NNUE::evaluate(pos) * scale / 1024 + Tempo;
+         Value nnue = NNUE::evaluate(pos) * scale / 1024 + Time.tempoNNUE;
 
          if (pos.is_chess960())
              nnue += fix_FRC(pos);
@@ -1104,23 +1116,26 @@ Value Eval::evaluate(const Position& pos) {
          return nnue;
       };
 
-      // If there is PSQ imbalance use classical eval, with small probability if it is small
+      // If there is PSQ imbalance we use the classical eval. We also introduce
+      // a small probability of using the classical eval when PSQ imbalance is small.
       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 || (psq > PawnValueMg / 4 && !(pos.this_thread()->nodes & 0xB));
 
       // Use classical evaluation for really low piece endgames.
-      // The most critical case is a bishop + A/H file pawn vs naked king draw.
-      bool strongClassical = pos.non_pawn_material() < 2 * RookValueMg && pos.count<PAWN>() < 2;
+      // 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 || strongClassical ? Evaluation<NO_TRACE>(pos).value() : adjusted_NNUE();
+      v = classical || lowPieceEndgame ? Evaluation<NO_TRACE>(pos).value() 
+                                       : adjusted_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 probability if the classical eval is less than the threshold.
-      if (   largePsq
-          && !strongClassical
+      // For the case of opposite colored bishops, switch to NNUE eval with small
+      // probability if the classical eval is less than the threshold.
+      if (    largePsq
+          && !lowPieceEndgame
           && (   abs(v) * 16 < NNUEThreshold2 * r50
               || (   pos.opposite_bishops()
                   && abs(v) * 16 < (NNUEThreshold1 + pos.non_pawn_material() / 64) * r50