Replace "use_raw_nnue_eval" with an uci option "Use NNUE pure"

src/evaluate.cpp

@@ -32,23 +32,32 @@
 #include "thread.h"
 #include "uci.h"
 
-#ifdef EVAL_LEARN
-namespace Learner
-{
-    extern bool use_raw_nnue_eval;
-}
-#endif
-
 namespace Eval {
 
-  bool useNNUE;
+  UseNNUEMode useNNUE;
   std::string eval_file_loaded="None";
 
+  static UseNNUEMode nnue_mode_from_option(const std::string& mode)
+  {
+    if (mode == "false")
+      return UseNNUEMode::False;
+    else if (mode == "true")
+      return UseNNUEMode::True;
+
+#ifdef EVAL_LEARN
+    else if (mode == "pure")
+      return UseNNUEMode::Pure;
+#endif
+
+    return UseNNUEMode::False;
+  }
+
   void init_NNUE() {
 
-    useNNUE = Options["Use NNUE"];
+    useNNUE = nnue_mode_from_option(Options["Use NNUE"]);
+
     std::string eval_file = std::string(Options["EvalFile"]);
-    if (useNNUE && eval_file_loaded != eval_file)
+    if (useNNUE != UseNNUEMode::False && eval_file_loaded != eval_file)
         if (Eval::NNUE::load_eval_file(eval_file))
             eval_file_loaded = eval_file;
   }
@@ -56,8 +65,7 @@ namespace Eval {
   void verify_NNUE() {
 
     std::string eval_file = std::string(Options["EvalFile"]);
-    if (useNNUE && eval_file_loaded != eval_file)
+    if (useNNUE != UseNNUEMode::False && eval_file_loaded != eval_file)    {
-    {
         UCI::OptionsMap defaults;
         UCI::init(defaults);
 
@@ -69,7 +77,7 @@ namespace Eval {
         std::exit(EXIT_FAILURE);
     }
 
-    if (useNNUE)
+    if (useNNUE != UseNNUEMode::False)
         sync_cout << "info string NNUE evaluation using " << eval_file << " enabled." << sync_endl;
     else
         sync_cout << "info string classical evaluation enabled." << sync_endl;
@@ -948,17 +956,17 @@ make_v:
 
 Value Eval::evaluate(const Position& pos) {
 #ifdef EVAL_LEARN
-  if (Learner::use_raw_nnue_eval) {
+  if (useNNUE == UseNNUEMode::Pure) {
       return NNUE::evaluate(pos);
   }
 #endif
 
-  bool classical = !Eval::useNNUE
+  bool classical = useNNUE == UseNNUEMode::False
-                ||  abs(eg_value(pos.psq_score())) * 16 > NNUEThreshold1 * (16 + pos.rule50_count());
+                || abs(eg_value(pos.psq_score())) * 16 > NNUEThreshold1 * (16 + pos.rule50_count());
   Value v = classical ? Evaluation<NO_TRACE>(pos).value()
                       : NNUE::evaluate(pos) * 5 / 4 + Tempo;
 
-  if (classical && Eval::useNNUE && abs(v) * 16 < NNUEThreshold2 * (16 + pos.rule50_count()))
+  if (classical && useNNUE != UseNNUEMode::False && abs(v) * 16 < NNUEThreshold2 * (16 + pos.rule50_count()))
       v = NNUE::evaluate(pos) * 5 / 4 + Tempo;
 
   // Damp down the evaluation linearly when shuffling
@@ -1015,7 +1023,7 @@ std::string Eval::trace(const Position& pos) {
 
   ss << "\nClassical evaluation: " << to_cp(v) << " (white side)\n";
 
-  if (Eval::useNNUE)
+  if (useNNUE != UseNNUEMode::False)
   {
       v = NNUE::evaluate(pos);
       v = pos.side_to_move() == WHITE ? v : -v;

src/evaluate.h

@@ -26,11 +26,20 @@
 class Position;
 
 namespace Eval {
+  enum struct UseNNUEMode
+  {
+    False,
+    True
+
+#ifdef EVAL_LEARN
+    ,Pure
+#endif
+  };
 
   std::string trace(const Position& pos);
   Value evaluate(const Position& pos);
 
-  extern bool useNNUE;
+  extern UseNNUEMode useNNUE;
   extern std::string eval_file_loaded;
   void init_NNUE();
   void verify_NNUE();

src/learn/gensfen.cpp

@@ -44,12 +44,6 @@ namespace Learner
     static bool detect_draw_by_consecutive_low_score = false;
     static bool detect_draw_by_insufficient_mating_material = false;
 
-    // Use raw NNUE eval value in the Eval::evaluate().
-    // If hybrid eval is enabled, training data
-    // generation and training don't work well.
-    // https://discordapp.com/channels/435943710472011776/733545871911813221/748524079761326192
-    extern bool use_raw_nnue_eval;
-
     static SfenOutputType sfen_output_type = SfenOutputType::Bin;
 
     static bool ends_with(const std::string& lhs, const std::string& end)
@@ -1111,8 +1105,6 @@ namespace Learner
                 is >> detect_draw_by_consecutive_low_score;
             else if (token == "detect_draw_by_insufficient_mating_material")
                 is >> detect_draw_by_insufficient_mating_material;
-            else if (token == "use_raw_nnue_eval")
-                is >> use_raw_nnue_eval;
             else if (token == "sfen_format")
                 is >> sfen_format;
             else

src/learn/learner.cpp

@@ -93,12 +93,6 @@ namespace Learner
     // data directly. In those cases, we set false to this variable.
     static bool convert_teacher_signal_to_winning_probability = true;
 
-    // Use raw NNUE eval value in the Eval::evaluate(). If hybrid eval is enabled, training data
-    // generation and training don't work well.
-    // https://discordapp.com/channels/435943710472011776/733545871911813221/748524079761326192
-    // This CANNOT be static since it's used elsewhere.
-    bool use_raw_nnue_eval = false;
-
     // Using stockfish's WDL with win rate model instead of sigmoid
     static bool use_wdl = false;
 
@@ -1811,7 +1805,6 @@ namespace Learner
             else if (option == "dest_score_min_value") is >> dest_score_min_value;
             else if (option == "dest_score_max_value") is >> dest_score_max_value;
             else if (option == "convert_teacher_signal_to_winning_probability") is >> convert_teacher_signal_to_winning_probability;
-            else if (option == "use_raw_nnue_eval") is >> use_raw_nnue_eval;
 
             // Otherwise, it's a filename.
             else

src/position.cpp

@@ -755,7 +755,7 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) {
       else
           st->nonPawnMaterial[them] -= PieceValue[MG][captured];
 
-      if (Eval::useNNUE)
+      if (Eval::useNNUE != Eval::UseNNUEMode::False)
       {
           dp.dirty_num = 2;  // 1 piece moved, 1 piece captured
           dp.piece[1] = captured;
@@ -799,7 +799,7 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) {
   // Move the piece. The tricky Chess960 castling is handled earlier
   if (type_of(m) != CASTLING)
   {
-      if (Eval::useNNUE)
+      if (Eval::useNNUE != Eval::UseNNUEMode::False)
       {
           dp.piece[0] = pc;
           dp.from[0] = from;
@@ -830,7 +830,7 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) {
           remove_piece(to);
           put_piece(promotion, to);
 
-          if (Eval::useNNUE)
+          if (Eval::useNNUE != Eval::UseNNUEMode::False)
           {
               // Promoting pawn to SQ_NONE, promoted piece from SQ_NONE
               dp.to[0] = SQ_NONE;
@@ -968,7 +968,7 @@ void Position::do_castling(Color us, Square from, Square& to, Square& rfrom, Squ
   rto = relative_square(us, kingSide ? SQ_F1 : SQ_D1);
   to = relative_square(us, kingSide ? SQ_G1 : SQ_C1);
 
-  if (Do && Eval::useNNUE)
+  if (Do && Eval::useNNUE != Eval::UseNNUEMode::False)
   {
       auto& dp = st->dirtyPiece;
       dp.piece[0] = make_piece(us, KING);
@@ -997,7 +997,7 @@ void Position::do_null_move(StateInfo& newSt) {
   assert(!checkers());
   assert(&newSt != st);
 
-  if (Eval::useNNUE)
+  if (Eval::useNNUE != Eval::UseNNUEMode::False)
   {
       std::memcpy(&newSt, st, sizeof(StateInfo));
       st->accumulator.computed_score = false;

src/ucioption.cpp

@@ -86,7 +86,11 @@ void init(OptionsMap& o) {
   o["SyzygyProbeDepth"]      << Option(1, 1, 100);
   o["Syzygy50MoveRule"]      << Option(true);
   o["SyzygyProbeLimit"]      << Option(7, 0, 7);
-  o["Use NNUE"]              << Option(true, on_use_NNUE);
+#ifdef EVAL_LEARN
+  o["Use NNUE"]              << Option("true var true var false var pure", "true", on_use_NNUE);
+#else
+  o["Use NNUE"]              << Option("true var true var false", "true", on_use_NNUE);
+#endif
   // The default must follow the format nn-[SHA256 first 12 digits].nnue
   // for the build process (profile-build and fishtest) to work.
   o["EvalFile"]              << Option("nn-82215d0fd0df.nnue", on_eval_file);