pub unsafe extern "C" fn fftw_plan_guru_split_dft_r2c(
rank: c_int,
dims: *const fftw_iodim,
howmany_rank: c_int,
howmany_dims: *const fftw_iodim,
in_: *mut f64,
ro: *mut f64,
io: *mut f64,
flags: c_uint,
) -> fftw_plan