Side Effects

Following calculation of the autocorrelation of a, a may be destroyed, since it is used internally as auxiliary storage. If its contents will be reused after autocorrelation is performed, first copy it to a temporary array.

S3L_acorr is most efficient when all arrays have the same length and when this length is one that can be computed efficiently via S3L_fft, or S3L_rc_fft. See "S3L_fft " and "S3L_rc_fft and S3L_cr_fft " for more information about execution efficiency.