47 gr_complex corr(gr_complex *x,gr_complex *y,
int len);
48 gr_complex corr(gr_complex *res, gr_complex *x, gr_complex *y,
int len);
55 gr_vector_int &ninput_items_required);
58 int work(
int noutput_items,
59 gr_vector_const_void_star &input_items,
60 gr_vector_void_star &output_items);