Description

S3L_rc_fft_setup allocates a real-to-complex FFT setup that includes the twiddle factors necessary for the computation and other internal structures. This setup depends only on the dimensions of the array whose FFT needs to be computed, and can be used both for the forward (real-to-complex) and inverse (complex-to-real) FFTs. Therefore, to compute multiple real-to-complex or complex-to-real Fourier transforms of different arrays whose extents are the same, the S3L_rc_fft_setup function has to be called only once.