Small cleanups 12

- Clean signature of functions in namespace NNUE
- Add comment for countermove based pruning
- Remove bestMoveCount variable
- Add const qualifier to kpp_board_index array
- Fix spaces in get_best_thread()
- Fix indention in capture LMR code in search.cpp
- Rename TtmemDeleter to LargePageDeleter

Closes https://github.com/official-stockfish/Stockfish/pull/3063

No functional change

src/evaluate.cpp

@@ -60,7 +60,7 @@ namespace Eval {
   bool useNNUE;
   string eval_file_loaded = "None";
 
-  /// init_NNUE() tries to load a nnue network at startup time, or when the engine
+  /// 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"
   /// The name of the nnue network is always retrieved from the EvalFile option.
   /// We search the given network in three locations: internally (the default
@@ -68,7 +68,7 @@ namespace Eval {
   /// in the engine directory. Distro packagers may define the DEFAULT_NNUE_DIRECTORY
   /// variable to have the engine search in a special directory in their distro.
 
-  void init_NNUE() {
+  void NNUE::init() {
 
     useNNUE = Options["Use NNUE"];
     if (!useNNUE)
@@ -111,8 +111,8 @@ namespace Eval {
         }
   }
 
-  /// verify_NNUE() verifies that the last net used was loaded successfully
-  void verify_NNUE() {
+  /// NNUE::verify() verifies that the last net used was loaded successfully
+  void NNUE::verify() {
 
     string eval_file = string(Options["EvalFile"]);
 

src/evaluate.h

@@ -32,8 +32,6 @@ namespace Eval {
 
   extern bool useNNUE;
   extern std::string eval_file_loaded;
-  void init_NNUE();
-  void verify_NNUE();
 
   // The default net name MUST follow the format nn-[SHA256 first 12 digits].nnue
   // for the build process (profile-build and fishtest) to work. Do not change the
@@ -43,9 +41,9 @@ namespace Eval {
   namespace NNUE {
 
     Value evaluate(const Position& pos);
-    Value compute_eval(const Position& pos);
-    void  update_eval(const Position& pos);
-    bool  load_eval(std::string streamName, std::istream& stream);
+    bool load_eval(std::string name, std::istream& stream);
+    void init();
+    void verify();
 
   } // namespace NNUE
 

src/main.cpp

@@ -45,7 +45,7 @@ int main(int argc, char* argv[]) {
   Endgames::init();
   Threads.set(size_t(Options["Threads"]));
   Search::clear(); // After threads are up
-  Eval::init_NNUE();
+  Eval::NNUE::init();
 
   UCI::loop(argc, argv);
 

src/nnue/evaluate_nnue.cpp

@@ -30,7 +30,7 @@
 
 namespace Eval::NNUE {
 
-  uint32_t kpp_board_index[PIECE_NB][COLOR_NB] = {
+  const uint32_t kpp_board_index[PIECE_NB][COLOR_NB] = {
    // convention: W - us, B - them
    // viewed from other side, W and B are reversed
       { PS_NONE,     PS_NONE     },
@@ -136,10 +136,10 @@ namespace Eval::NNUE {
   }
 
   // Load eval, from a file stream or a memory stream
-  bool load_eval(std::string streamName, std::istream& stream) {
+  bool load_eval(std::string name, std::istream& stream) {
 
     Initialize();
-    fileName = streamName;
+    fileName = name;
     return ReadParameters(stream);
   }
 

src/nnue/evaluate_nnue.h

@@ -41,7 +41,7 @@ namespace Eval::NNUE {
   };
 
   template <typename T>
-  struct TtmemDeleter {
+  struct LargePageDeleter {
     void operator()(T* ptr) const {
       ptr->~T();
       aligned_large_pages_free(ptr);
@@ -52,7 +52,7 @@ namespace Eval::NNUE {
   using AlignedPtr = std::unique_ptr<T, AlignedDeleter<T>>;
 
   template <typename T>
-  using LargePagePtr = std::unique_ptr<T, TtmemDeleter<T>>;
+  using LargePagePtr = std::unique_ptr<T, LargePageDeleter<T>>;
 
 }  // namespace Eval::NNUE
 

src/nnue/nnue_common.h

@@ -113,7 +113,7 @@ namespace Eval::NNUE {
     PS_END2     = 12 * SQUARE_NB + 1
   };
 
-  extern uint32_t kpp_board_index[PIECE_NB][COLOR_NB];
+  extern const uint32_t kpp_board_index[PIECE_NB][COLOR_NB];
 
   // Type of input feature after conversion
   using TransformedFeatureType = std::uint8_t;

src/search.cpp

@@ -225,7 +225,7 @@ void MainThread::search() {
   Time.init(Limits, us, rootPos.game_ply());
   TT.new_search();
 
-  Eval::verify_NNUE();
+  Eval::NNUE::verify();
 
   if (rootMoves.empty())
   {
@@ -462,10 +462,7 @@ void Thread::search() {
                   ++failedHighCnt;
               }
               else
-              {
-                  ++rootMoves[pvIdx].bestMoveCount;
                   break;
-              }
 
               delta += delta / 4 + 5;
 
@@ -1570,6 +1567,7 @@ moves_loop: // When in check, search starts from here
                                                                 [pos.moved_piece(move)]
                                                                 [to_sq(move)];
 
+      // CounterMove based pruning
       if (  !captureOrPromotion
           && moveCount
           && (*contHist[0])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold

src/search.h

@@ -71,7 +71,6 @@ struct RootMove {
   Value previousScore = -VALUE_INFINITE;
   int selDepth = 0;
   int tbRank = 0;
-  int bestMoveCount = 0;
   Value tbScore;
   std::vector<Move> pv;
 };

src/uci.cpp

@@ -85,7 +85,7 @@ namespace {
     Position p;
     p.set(pos.fen(), Options["UCI_Chess960"], &states->back(), Threads.main());
 
-    Eval::verify_NNUE();
+    Eval::NNUE::verify();
 
     sync_cout << "\n" << Eval::trace(p) << sync_endl;
   }

src/ucioption.cpp

@@ -41,8 +41,8 @@ void on_hash_size(const Option& o) { TT.resize(size_t(o)); }
 void on_logger(const Option& o) { start_logger(o); }
 void on_threads(const Option& o) { Threads.set(size_t(o)); }
 void on_tb_path(const Option& o) { Tablebases::init(o); }
-void on_use_NNUE(const Option& ) { Eval::init_NNUE(); }
-void on_eval_file(const Option& ) { Eval::init_NNUE(); }
+void on_use_NNUE(const Option& ) { Eval::NNUE::init(); }
+void on_eval_file(const Option& ) { Eval::NNUE::init(); }
 
 /// Our case insensitive less() function as required by UCI protocol
 bool CaseInsensitiveLess::operator() (const string& s1, const string& s2) const {