let hsize = (1 << (bits - 1)) as usize;
self.do_fft_inplace_ct(&mut data[0..hsize], bits - 1, forward);
self.do_fft_inplace_ct(&mut data[hsize..], bits - 1, forward);
let hsize = (1 << (bits - 1)) as usize;
self.do_fft_inplace_ct(&mut data[0..hsize], bits - 1, forward);
self.do_fft_inplace_ct(&mut data[hsize..], bits - 1, forward);