CC = clangCFLAGS = -O3 -Ofast -std=c++20 -gLDFLAGS =LDLIBS = -lmINCLUDES = # Detect the C++ standard library to link againstifeq ($(shell echo 'int main(){}' | $(CC) -lc++ -x c++ - -o /dev/null 2>/dev/null; echo $$?), 0)  LDLIBS += -lc++else  LDLIBS += -lstdc++endif # Check if OpenMP is available# This is done by attempting to compile a file that includes omp.h# OpenMP makes the code a lot faster so I advise installing it# e.g. on MacOS: brew install libomp# e.g. on Ubuntu: sudo apt-get install libomp-dev# later, run the program by prepending the number of threads, e.g.: OMP_NUM_THREADS=8 ./train_gpt2ifeq ($(shell printf '\#include <omp.h>\nint main(){return 0;}' | $(CC) -fopenmp -x c - -o /dev/null > /dev/null 2>&1; echo $$?), 0)  ifeq ($(shell uname), Darwin)    # macOS with Homebrew    CFLAGS += -Xclang -fopenmp    LDFLAGS += -L/opt/homebrew/opt/libomp/lib    LDLIBS += -lomp    INCLUDES += -I/opt/homebrew/opt/libomp/include  else    # Ubuntu or other Linux distributions    CFLAGS += -fopenmp    LDLIBS += -lgomp  endif  $(info NICE Compiling with OpenMP support)else  $(warning OOPS Compiling without OpenMP support)endif # PHONY means these targets will always be executed.PHONY: all train_gpt2 test_gpt2 test_tensor clean # default target is allall: train_gpt2 test_gpt2 test_tensor train_gpt2: train_gpt2.cpp	$(CC) $(CFLAGS) $(INCLUDES) $(LDFLAGS) $< $(LDLIBS) -o $@ test_gpt2: test_gpt2.cpp	$(CC) $(CFLAGS) $(INCLUDES) $(LDFLAGS) $< $(LDLIBS) -o $@ test_tensor: test_tensor.cpp	$(CC) $(CFLAGS) $(INCLUDES) $(LDFLAGS) $^ ${LDLIBS} -o $@ clean:	rm -f train_gpt2 test_gpt2 test_tensor