template<typename backend_tag, typename input, typename output>
struct heffte::backend::check_types< backend_tag, input, output, typename std::enable_if< not uses_fft_types< backend_tag >::value and((std::is_same< input, float >::value and std::is_same< output, float >::value) or(std::is_same< input, double >::value and std::is_same< output, double >::value))>::type >
Defines the types compatible for a cos() transform.