refactor: 源码迁至 engines/src/，删除旧的 engines/{c,cpp,fortran}/

- 删除 engines/{c,cpp,fortran}/ 目录（源码和 Makefile 已移至 src/）
- engines/src/{c,cpp,fortran}/: 清理 main.*/bak 等无用文件
- Makefile 改为直接编译 DLL 到 engines/release/
- .gitignore: 更新路径指向 engines/src/*/build/
- engine_dll.py: 更新注释中的编译命令路径

engines/src/c/Makefile

@@ -1,82 +1,40 @@
-# engines/c/Makefile
-# 跨平台编译：make         → 本地系统编译
-#              make linux  → Linux 交叉编译（需 x86_64-linux-gnu-gcc）
-#              make windows → Windows 交叉编译（需 x86_64-w64-mingw32-gcc）
-#              make macos  → macOS 交叉编译（需 osxcross 工具链）
+# engines/src/c/Makefile
+# 编译 DLL 到 engines/release/（主程序通过 ctypes 直接调用）
 
 CC        = gcc
 CFLAGS    = -O3 -march=native -Wall -Wextra
 LDFLAGS   = -lm
-SRCS      = main.c
 LIB_SRC   = dynamics_lib.c
 
 # 自动检测系统
 UNAME_S  := $(shell uname -s 2>/dev/null || echo Windows)
 
-# 目标文件名：统一使用 .exe 后缀（方便 Python 跨平台调用）
-TARGET    = build/dynamics_c.exe
+# DLL 输出到 engines/release/
+DLL_DIR = ../../release
 
-# DLL 目标（平台自动选择后缀）
 ifeq ($(UNAME_S),Linux)
-  DLL_TARGET = build/dynamics_c.so
+  DLL_TARGET = $(DLL_DIR)/dynamics_c.so
   DLL_FLAGS  = -shared -fPIC
 else ifeq ($(UNAME_S),Darwin)
-  DLL_TARGET = build/dynamics_c.dylib
+  DLL_TARGET = $(DLL_DIR)/dynamics_c.dylib
   DLL_FLAGS  = -dynamiclib
 else
-  DLL_TARGET = build/dynamics_c.dll
+  DLL_TARGET = $(DLL_DIR)/dynamics_c.dll
   DLL_FLAGS  = -shared
 endif
 
-# ── 本地编译 ─────────────────────────────────
-.PHONY: all dll clean linux windows macos
+.PHONY: all dll clean
 
-all: $(TARGET)
+all: dll
 
 dll: $(DLL_TARGET)
 
-$(TARGET): $(SRCS) | build
-	$(CC) $(CFLAGS) -o $@ $(SRCS) $(LDFLAGS)
-	@echo "  === C engine built: $@ ==="
-
-$(DLL_TARGET): $(LIB_SRC) | build
+$(DLL_TARGET): $(LIB_SRC) | $(DLL_DIR)
 	$(CC) $(CFLAGS) $(DLL_FLAGS) -o $@ $(LIB_SRC) $(LDFLAGS)
 	@echo "  === C DLL built: $@ ==="
 
-build:
-	mkdir -p build
-
-# ── 交叉编译 ─────────────────────────────────
-# Linux → Linux (x86_64)
-linux: CROSS_PREFIX = x86_64-linux-gnu-
-linux: CC = $(CROSS_PREFIX)gcc
-linux: CFLAGS = -O3 -march=x86-64 -Wall -Wextra
-linux: $(SRCS) | build
-	$(CC) $(CFLAGS) -o build/dynamics_c_linux.exe $(SRCS) $(LDFLAGS)
-	@echo "  === Linux binary: build/dynamics_c_linux.exe ==="
-
-# 任意平台 → Windows (x86_64)
-# 需要安装 MinGW 交叉编译器：
-#   apt install mingw-w64 (Debian/Ubuntu)
-#   brew install mingw-w64 (macOS)
-windows: CROSS_PREFIX = x86_64-w64-mingw32-
-windows: CC = $(CROSS_PREFIX)gcc
-windows: CFLAGS = -O3 -march=x86-64 -Wall -Wextra
-windows: $(SRCS) | build
-	$(CC) $(CFLAGS) -o build/dynamics_c_win.exe $(SRCS) $(LDFLAGS)
-	@echo "  === Windows binary: build/dynamics_c_win.exe ==="
-
-# 任意平台 → macOS (x86_64)
-# 需要安装 osxcross 工具链
-macos: CROSS_PREFIX = x86_64-apple-darwin-
-macos: CC = $(CROSS_PREFIX)gcc
-macos: CFLAGS = -O3 -march=x86-64 -Wall -Wextra
-macos: $(SRCS) | build
-	$(CC) $(CFLAGS) -o build/dynamics_c_mac.exe $(SRCS) $(LDFLAGS)
-	@echo "  === macOS binary: build/dynamics_c_mac.exe ==="
-
-# ── 编译所有平台 ──────────────────────────────
-all-platforms: linux windows macos
+$(DLL_DIR):
+	mkdir -p $(DLL_DIR)
 
 clean:
-	rm -rf build *.o
+	rm -f $(DLL_TARGET)

engines/src/cpp/Makefile

@@ -1,49 +1,46 @@
-# engines/cpp/Makefile
+# engines/src/cpp/Makefile
+# 编译 DLL 到 engines/release/（主程序通过 ctypes 直接调用）
 
 CXX     = g++
-SRCS    = main.cpp
 LIB_SRC = dynamics_lib.cpp
 
 UNAME_S := $(shell uname -s 2>/dev/null || echo Windows)
 
 CXXFLAGS = -O3 -march=native -std=c++17 -Wall -Wextra -D_USE_MATH_DEFINES
 
-# Windows 下静态链接运行时，避免 libstdc++-6.dll / libgcc_s_seh-1.dll 版本冲突
+# Windows 下静态链接运行时
 ifeq ($(UNAME_S),Windows)
   STATIC_FLAGS = -static-libgcc -static-libstdc++
 else
   STATIC_FLAGS =
 endif
 
-TARGET = build/dynamics_cpp.exe
+# DLL 输出到 engines/release/
+DLL_DIR = ../../release
 
 ifeq ($(UNAME_S),Linux)
-  DLL_TARGET = build/dynamics_cpp.so
+  DLL_TARGET = $(DLL_DIR)/dynamics_cpp.so
   DLL_FLAGS  = -shared -fPIC
 else ifeq ($(UNAME_S),Darwin)
-  DLL_TARGET = build/dynamics_cpp.dylib
+  DLL_TARGET = $(DLL_DIR)/dynamics_cpp.dylib
   DLL_FLAGS  = -dynamiclib
 else
-  DLL_TARGET = build/dynamics_cpp.dll
+  DLL_TARGET = $(DLL_DIR)/dynamics_cpp.dll
   DLL_FLAGS  = -shared
 endif
 
 .PHONY: all dll clean
 
-all: $(TARGET)
+all: dll
 
 dll: $(DLL_TARGET)
 
-$(TARGET): $(SRCS) | build
-	$(CXX) $(CXXFLAGS) $(STATIC_FLAGS) -o $@ $(SRCS)
-	@echo "  === C++ engine built: $@ ==="
-
-$(DLL_TARGET): $(LIB_SRC) | build
+$(DLL_TARGET): $(LIB_SRC) | $(DLL_DIR)
 	$(CXX) $(CXXFLAGS) $(STATIC_FLAGS) $(DLL_FLAGS) -o $@ $(LIB_SRC)
 	@echo "  === C++ DLL built: $@ ==="
 
-build:
-	mkdir -p build
+$(DLL_DIR):
+	mkdir -p $(DLL_DIR)
 
 clean:
-	rm -rf build *.o
+	rm -f $(DLL_TARGET)

engines/src/fortran/Makefile

@@ -1,47 +1,44 @@
-# engines/fortran/Makefile
+# engines/src/fortran/Makefile
+# 编译 DLL 到 engines/release/（主程序通过 ctypes 直接调用）
 
 FC      = gfortran
 FFLAGS  = -O3 -march=native -Wall -Wextra
-SRCS    = main.f90
 LIB_SRC = dynamics_lib.f90
 
 UNAME_S := $(shell uname -s 2>/dev/null || echo Windows)
 
 ifeq ($(UNAME_S),Windows)
-  STATIC_FLAGS = -static-libgcc -static-libgfortran -static-libquadmath
+  STATIC_FLAGS = -static
 else
   STATIC_FLAGS =
 endif
 
-TARGET = build/dynamics_f90.exe
+# DLL 输出到 engines/release/
+DLL_DIR = ../../release
 
 ifeq ($(UNAME_S),Linux)
-  DLL_TARGET = build/dynamics_f90.so
+  DLL_TARGET = $(DLL_DIR)/dynamics_f90.so
   DLL_FLAGS  = -shared -fPIC
 else ifeq ($(UNAME_S),Darwin)
-  DLL_TARGET = build/dynamics_f90.dylib
+  DLL_TARGET = $(DLL_DIR)/dynamics_f90.dylib
   DLL_FLAGS  = -dynamiclib
 else
-  DLL_TARGET = build/dynamics_f90.dll
+  DLL_TARGET = $(DLL_DIR)/dynamics_f90.dll
   DLL_FLAGS  = -shared -fPIC
 endif
 
 .PHONY: all dll clean
 
-all: $(TARGET)
+all: dll
 
 dll: $(DLL_TARGET)
 
-$(TARGET): $(SRCS) | build
-	$(FC) $(FFLAGS) $(STATIC_FLAGS) -o $@ $(SRCS)
-	@echo "  === Fortran engine built: $@ ==="
-
-$(DLL_TARGET): $(LIB_SRC) | build
+$(DLL_TARGET): $(LIB_SRC) | $(DLL_DIR)
 	$(FC) $(FFLAGS) $(STATIC_FLAGS) $(DLL_FLAGS) -o $@ $(LIB_SRC)
 	@echo "  === Fortran DLL built: $@ ==="
 
-build:
-	mkdir -p build
+$(DLL_DIR):
+	mkdir -p $(DLL_DIR)
 
 clean:
-	rm -rf build *.o *.mod
+	rm -f $(DLL_TARGET)