Refactor Network Usage

This update improves how Pikafish handles network
usage, making it easier to manage and modify networks in the future.

With the introduction of a dedicated Network class, creating networks has become
straightforward. See uci.cpp:
```cpp
NN::Network({EvalFileDefaultName, "None", ""})
```

The new `Network` encapsulates all network-related logic, significantly reducing
the complexity previously required to support multiple network types.

No functional change

src/Makefile

@@ -55,16 +55,16 @@ PGOBENCH = $(WINE_PATH) ./$(EXE) bench
 SRCS = benchmark.cpp bitboard.cpp evaluate.cpp main.cpp \
 	misc.cpp movegen.cpp movepick.cpp position.cpp \
 	search.cpp thread.cpp timeman.cpp tt.cpp uci.cpp ucioption.cpp tune.cpp \
-	nnue/evaluate_nnue.cpp nnue/features/half_ka_v2_hm.cpp \
+	nnue/nnue_misc.cpp nnue/features/half_ka_v2_hm.cpp nnue/network.cpp \
 	external/zip.cpp
 
 HEADERS = benchmark.h bitboard.h evaluate.h misc.h movegen.h movepick.h magics.h \
-           nnue/evaluate_nnue.h nnue/features/half_ka_v2_hm.h nnue/layers/affine_transform.h \
+           nnue/nnue_misc.h nnue/features/half_ka_v2_hm.h nnue/layers/affine_transform.h \
            nnue/layers/affine_transform_sparse_input.h nnue/layers/clipped_relu.h nnue/layers/simd.h \
            nnue/layers/sqr_clipped_relu.h nnue/nnue_accumulator.h nnue/nnue_architecture.h \
            nnue/nnue_common.h nnue/nnue_feature_transformer.h position.h \
            search.h thread.h thread_win32_osx.h timeman.h \
-           tt.h tune.h types.h uci.h ucioption.h perft.h \
+           tt.h tune.h types.h uci.h ucioption.h perft.h nnue/network.cpp \
            external/zip.h external/miniz.h
 
 OBJS = $(notdir $(SRCS:.cpp=.o))

src/evaluate.cpp

@@ -22,99 +22,18 @@
 #include <cassert>
 #include <cmath>
 #include <cstdlib>
-#include <fstream>
 #include <iomanip>
 #include <iostream>
-#include <optional>
 #include <sstream>
-#include <vector>
 
-#include "misc.h"
-#include "nnue/evaluate_nnue.h"
+#include "nnue/network.h"
+#include "nnue/nnue_misc.h"
 #include "position.h"
 #include "types.h"
 #include "uci.h"
-#include "ucioption.h"
 
 namespace Stockfish {
 
-namespace Eval {
-
-std::string currentEvalFileName = "None";
-
-// Tries to load a NNUE network at startup time, or when the engine
-// receives a UCI command "setoption name EvalFile value .*.nnue"
-// The name of the NNUE network is always retrieved from the EvalFile option.
-// We search the given network in two locations: in the active working directory and
-// in the engine directory.
-EvalFile NNUE::load_networks(const std::string& rootDirectory,
-                             const OptionsMap&  options,
-                             EvalFile           evalFile) {
-
-    std::string user_eval_file = options[evalFile.optionName];
-
-    if (user_eval_file.empty())
-        user_eval_file = evalFile.defaultName;
-
-    std::vector<std::string> dirs = {"", rootDirectory};
-
-    for (const std::string& directory : dirs)
-        if (evalFile.current != user_eval_file)
-        {
-            std::stringstream ss          = read_zipped_nnue(directory + user_eval_file);
-            auto              description = NNUE::load_eval(ss);
-            if (!description.has_value())
-            {
-                std::ifstream stream(directory + user_eval_file, std::ios::binary);
-                description = NNUE::load_eval(stream);
-            }
-
-            if (description.has_value())
-            {
-                evalFile.current        = user_eval_file;
-                evalFile.netDescription = description.value();
-            }
-        }
-
-    return evalFile;
-}
-
-// Verifies that the last net used was loaded successfully
-void NNUE::verify(const OptionsMap& options, const EvalFile& evalFile) {
-
-    std::string user_eval_file = options[evalFile.optionName];
-
-    if (user_eval_file.empty())
-        user_eval_file = evalFile.defaultName;
-
-    if (evalFile.current != user_eval_file)
-    {
-
-        std::string msg1 =
-          "Network evaluation parameters compatible with the engine must be available.";
-        std::string msg2 = "The network file " + user_eval_file + " was not loaded successfully.";
-        std::string msg3 = "The UCI option EvalFile might need to specify the full path, "
-                           "including the directory name, to the network file.";
-        std::string msg4 =
-          "The default net can be downloaded from: "
-          "https://github.com/official-pikafish/Networks/releases/download/master-net/"
-          + evalFile.defaultName;
-        std::string msg5 = "The engine will be terminated now.";
-
-        sync_cout << "info string ERROR: " << msg1 << sync_endl;
-        sync_cout << "info string ERROR: " << msg2 << sync_endl;
-        sync_cout << "info string ERROR: " << msg3 << sync_endl;
-        sync_cout << "info string ERROR: " << msg4 << sync_endl;
-        sync_cout << "info string ERROR: " << msg5 << sync_endl;
-
-        exit(EXIT_FAILURE);
-    }
-
-    sync_cout << "info string NNUE evaluation using " << user_eval_file << " enabled" << sync_endl;
-}
-}
-
-
 // Returns a static, purely materialistic evaluation of the position from
 // the point of view of the given color. It can be divided by PawnValue to get
 // an approximation of the material advantage on the board in terms of pawns.
@@ -127,7 +46,7 @@ int Eval::simple_eval(const Position& pos, Color c) {
 
 // Evaluate is the evaluator for the outer world. It returns a static evaluation
 // of the position from the point of view of the side to move.
-Value Eval::evaluate(const Position& pos, int optimism) {
+Value Eval::evaluate(const Eval::NNUE::Network& network, const Position& pos, int optimism) {
 
     assert(!pos.checkers());
 
@@ -137,7 +56,7 @@ Value Eval::evaluate(const Position& pos, int optimism) {
     int   simpleEval = simple_eval(pos, stm);
 
     int   nnueComplexity;
-    Value nnue = NNUE::evaluate(pos, true, &nnueComplexity);
+    Value nnue = network.evaluate(pos, true, &nnueComplexity);
 
     // Blend optimism and eval with nnue complexity and material imbalance
     optimism += optimism * (nnueComplexity + std::abs(simpleEval - nnue)) / 781;
@@ -159,24 +78,23 @@ Value Eval::evaluate(const Position& pos, int optimism) {
 // a string (suitable for outputting to stdout) that contains the detailed
 // descriptions and values of each evaluation term. Useful for debugging.
 // Trace scores are from white's point of view
-std::string Eval::trace(Position& pos) {
+std::string Eval::trace(Position& pos, const Eval::NNUE::Network& network) {
 
     if (pos.checkers())
         return "Final evaluation: none (in check)";
 
     std::stringstream ss;
     ss << std::showpoint << std::noshowpos << std::fixed << std::setprecision(2);
 
-    ss << '\n' << NNUE::trace(pos) << '\n';
+    ss << '\n' << NNUE::trace(pos, network) << '\n';
 
     ss << std::showpoint << std::showpos << std::fixed << std::setprecision(2) << std::setw(15);
 
-    Value v;
-    v = NNUE::evaluate(pos);
-    v = pos.side_to_move() == WHITE ? v : -v;
+    Value v = network.evaluate(pos);
+    v       = pos.side_to_move() == WHITE ? v : -v;
     ss << "NNUE evaluation        " << 0.01 * UCI::to_cp(v) << " (white side)\n";
 
-    v = evaluate(pos, VALUE_ZERO);
+    v = evaluate(network, pos, VALUE_ZERO);
     v = pos.side_to_move() == WHITE ? v : -v;
     ss << "Final evaluation       " << 0.01 * UCI::to_cp(v) << " (white side)";
     ss << " [with scaled NNUE, ...]";

src/evaluate.h

@@ -26,37 +26,23 @@
 namespace Stockfish {
 
 class Position;
-class OptionsMap;
 
 namespace Eval {
 
-std::string trace(Position& pos);
-
-int   simple_eval(const Position& pos, Color c);
-Value evaluate(const Position& pos, int optimism);
-
 // 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
-// name of the macro, as it is used in the Makefile.
+// name of the macro or the location where this macro is defined, as it is used
+// in the Makefile/Fishtest.
 #define EvalFileDefaultName "pikafish.nnue"
 
-struct EvalFile {
-    // UCI option name
-    std::string optionName;
-    // Default net name, will use one of the macros above
-    std::string defaultName;
-    // Selected net name, either via uci option or default
-    std::string current;
-    // Net description extracted from the net file
-    std::string netDescription;
-};
-
 namespace NNUE {
+class Network;
+}
 
-EvalFile load_networks(const std::string&, const OptionsMap&, EvalFile);
-void     verify(const OptionsMap&, const EvalFile&);
+std::string trace(Position& pos, const Eval::NNUE::Network& network);
 
-}  // namespace NNUE
+int   simple_eval(const Position& pos, Color c);
+Value evaluate(const NNUE::Network& network, const Position& pos, int optimism);
 
 }  // namespace Eval
 

src/main.cpp

@@ -16,7 +16,6 @@
 #include <iostream>
 
 #include "bitboard.h"
-#include "evaluate.h"
 #include "misc.h"
 #include "position.h"
 #include "tune.h"
@@ -36,8 +35,6 @@ int main(int argc, char* argv[]) {
 
     Tune::init(uci.options);
 
-    uci.evalFile = Eval::NNUE::load_networks(uci.working_directory(), uci.options, uci.evalFile);
-
     uci.loop();
 
     return 0;

src/misc.h

@@ -25,6 +25,7 @@
 #include <cstddef>
 #include <cstdint>
 #include <iosfwd>
+#include <memory>
 #include <string>
 #include <vector>
 
@@ -51,6 +52,30 @@ void aligned_large_pages_free(void* mem);
 
 std::stringstream read_zipped_nnue(const std::string& fpath);
 
+// Deleter for automating release of memory area
+template<typename T>
+struct AlignedDeleter {
+    void operator()(T* ptr) const {
+        ptr->~T();
+        std_aligned_free(ptr);
+    }
+};
+
+template<typename T>
+struct LargePageDeleter {
+    void operator()(T* ptr) const {
+        ptr->~T();
+        aligned_large_pages_free(ptr);
+    }
+};
+
+template<typename T>
+using AlignedPtr = std::unique_ptr<T, AlignedDeleter<T>>;
+
+template<typename T>
+using LargePagePtr = std::unique_ptr<T, LargePageDeleter<T>>;
+
+
 void dbg_hit_on(bool cond, int slot = 0);
 void dbg_mean_of(int64_t value, int slot = 0);
 void dbg_stdev_of(int64_t value, int slot = 0);