Fundamentally it required a single function – cross-correlation – to measure the similarity of two data samples (audio files in this case). And it turns out that Octave provides it in the box.

W. F. Welsh, On the Reliability of Cross‐Correlation Function LagDeterminations in ActiveGalactic Nuclei, Publications of the Astronomical Society of the Pacific, Vol. 111, No. 765 (November 1999), pp ...

Notably, a series of investigations have employed exact field-theoretical methods to derive analytic expressions for one- and two-point correlation functions in systems at phase coexistence.