if(NOT DEFINED ENV{CXXFLAGS})
    if(CMAKE_CXX_COMPILER_ID MATCHES Intel)
        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall")
        set(CMAKE_CXX_FLAGS_RELEASE "-O3")
        set(CMAKE_CXX_FLAGS_DEBUG "-O0 -g")
    endif()
endif()