Add cuda compile define and cmake setting

CMakeLists.txt

@@ -4,9 +4,14 @@ project(Aurora)
 set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_INCLUDE_CURRENT_DIR ON)
 
+set(Aurora_USE_CUDA ON)
+
+if (Aurora_USE_CUDA)
 set(CMAKE_CUDA_COMPILER /usr/local/cuda/bin/nvcc)
 enable_language(CUDA)
 find_package(CUDAToolkit REQUIRED)
+add_definitions(-DUSE_CUDA)
+endif(Aurora_USE_CUDA)
 
 find_package (OpenMP REQUIRED)
 set(CMAKE_C_FLAGS  "${CMAKE_C_FLAGS}  -march=native")
@@ -30,13 +35,14 @@ target_include_directories(Aurora PUBLIC $<TARGET_PROPERTY:MKL::MKL,INTERFACE_IN
 target_link_libraries(Aurora PUBLIC $<LINK_ONLY:MKL::MKL>)
 target_link_libraries(Aurora PUBLIC OpenMP::OpenMP_CXX)
 target_link_libraries(Aurora PUBLIC matio)
-
+if (Aurora_USE_CUDA)
 target_include_directories(Aurora PRIVATE ./src /usr/local/cuda/include) 
 set_target_properties(Aurora PROPERTIES CUDA_SEPARABLE_COMPILATION ON)
 target_compile_options(Aurora PRIVATE $<$<COMPILE_LANGUAGE:CUDA>:
     -arch=sm_75
 >)
 target_link_libraries(Aurora PRIVATE ${CUDA_RUNTIME_LIBRARY} CUDA::cufft CUDA::cudart)
+endif(Aurora_USE_CUDA)
 
 find_package(GTest  REQUIRED)
 INCLUDE_DIRECTORIES(${GTEST_INCLUDE_DIRS})
@@ -55,11 +61,13 @@ target_link_libraries(Aurora_Test PUBLIC OpenMP::OpenMP_CXX)
 target_link_libraries(Aurora_Test PUBLIC matio)
 target_link_libraries(Aurora_Test PUBLIC ${GTEST_BOTH_LIBRARIES}  )
 
+if (Aurora_USE_CUDA)
 target_include_directories(Aurora_Test PRIVATE ./src /usr/local/cuda/include) 
 set_target_properties(Aurora_Test PROPERTIES CUDA_SEPARABLE_COMPILATION ON)
 target_compile_options(Aurora_Test PRIVATE $<$<COMPILE_LANGUAGE:CUDA>:
     -arch=sm_75
 >)
 target_link_libraries(Aurora_Test PRIVATE ${CUDA_RUNTIME_LIBRARY} CUDA::cufft CUDA::cudart)
+endif(Aurora_USE_CUDA)
 gtest_discover_tests(Aurora_Test )
 #target_link_libraries(CreateMatchedFilter PRIVATE TBB::tbb)