Makefile

# N-Body Gravity Simulation Makefile
# Optimized for performance with C++20, OpenMP, and SIMD

# Detect compiler, OS, and architecture
UNAME_S := $(shell uname -s)
UNAME_M := $(shell uname -m)

ifeq ($(UNAME_S),Darwin)
    # macOS with Clang
    CXX = clang++
    CXXFLAGS = -std=c++20 -O3 -ffast-math -DNDEBUG
    CXXFLAGS += -Wall -Wextra -Wpedantic
    CXXFLAGS += -Iinclude

    # Architecture-specific optimizations
    ifeq ($(UNAME_M),arm64)
        # Apple Silicon (M1/M2/M3)
        CXXFLAGS += -mcpu=apple-m1
    else
        # Intel Mac
        CXXFLAGS += -march=native -mavx2 -mfma
    endif

    # Note: OpenMP disabled for now on macOS due to complexity
    LIBS = -lm
    DEBUG_FLAGS = -std=c++20 -O0 -g -Wall -Wextra -Wpedantic -fsanitize=address -fno-omit-frame-pointer -Iinclude
else
    # Linux with GCC
    CXX = g++
    CXXFLAGS = -std=c++20 -O3 -march=native -mtune=native -ffast-math -DNDEBUG
    CXXFLAGS += -Wall -Wextra -Wpedantic
    CXXFLAGS += -fopenmp -mavx2 -mfma
    CXXFLAGS += -Iinclude
    LIBS = -fopenmp -lm
    DEBUG_FLAGS = -std=c++20 -O0 -g -Wall -Wextra -Wpedantic -fopenmp -Iinclude
endif

# Source files
SRCDIR = src
SOURCES = $(wildcard $(SRCDIR)/*.cpp)
OBJECTS = $(SOURCES:.cpp=.o)

# Test files
TESTDIR = tests
TEST_SOURCES = $(wildcard $(TESTDIR)/*.cpp)
TEST_OBJECTS = $(TEST_SOURCES:.cpp=.o)

# Executables
TARGET = nbody_simulation
TEST_TARGET = test_vector3d

# Libraries (set above based on OS)

# Default target
all: $(TARGET)

# Main executable
$(TARGET): $(OBJECTS)
	$(CXX) $(CXXFLAGS) -o $@ $^ $(LIBS)
	@echo "Built $(TARGET) successfully!"

# Test executable (simplified - only Vector3D test)
test: $(TESTDIR)/test_vector3d.o $(SRCDIR)/Vector3D.o
	$(CXX) $(CXXFLAGS) -o $(TEST_TARGET) $^ $(LIBS)
	@echo "Built $(TEST_TARGET) successfully!"
	@echo "Running tests..."
	./$(TEST_TARGET)

# Debug build
debug: CXXFLAGS = $(DEBUG_FLAGS)
debug: $(TARGET)

# Object files
%.o: %.cpp
	$(CXX) $(CXXFLAGS) -c $< -o $@

# Clean
clean:
	rm -f $(OBJECTS) $(TEST_OBJECTS) $(TARGET) $(TEST_TARGET)
	@echo "Cleaned build files"

# Install dependencies (macOS with Homebrew)
install-deps:
	@echo "Installing dependencies..."
	@if command -v brew >/dev/null 2>&1; then \
		brew install nlohmann-json libomp; \
	else \
		echo "Homebrew not found. Please install nlohmann-json manually."; \
	fi

# Run with default configuration
run: $(TARGET)
	./$(TARGET) --preset earth-moon --duration 2629746 --output output/earth_moon_test.csv

# Run solar system simulation
run-solar: $(TARGET)
	./$(TARGET) --preset solar-system --duration 31557600 --output output/solar_system.csv

# Quick test run
quick-test: $(TARGET)
	./$(TARGET) --preset earth-moon --duration 86400 --timestep 3600 --output output/quick_test.csv

# Performance test
perf-test: $(TARGET)
	@echo "Running performance test..."
	time ./$(TARGET) --preset solar-system --duration 86400 --no-output --quiet

# Help
help:
	@echo "N-Body Gravity Simulation Build System"
	@echo "======================================"
	@echo "Targets:"
	@echo "  all          - Build main executable (default)"
	@echo "  test         - Build and run Vector3D tests"
	@echo "  debug        - Build with debug flags"
	@echo "  clean        - Remove build files"
	@echo "  install-deps - Install dependencies (macOS/Homebrew)"
	@echo "  run          - Run Earth-Moon simulation"
	@echo "  run-solar    - Run full solar system simulation"
	@echo "  quick-test   - Quick test run"
	@echo "  perf-test    - Performance benchmark"
	@echo "  help         - Show this help"
	@echo ""
	@echo "Compiler: $(CXX)"
	@echo "Flags: $(CXXFLAGS)"

# Create output directory
$(shell mkdir -p output)

.PHONY: all test debug clean install-deps run run-solar quick-test perf-test help