Creating improvisations on chord progressions using suffix trees. Issue 3 (2nd September 2018)

• Record Type: Journal Article
• Authors: Ayad, Lorraine A.K.; Chemillier, Marc; Pissis, Solon P.
• Is Part Of: Journal of mathematics and music. Volume 12:Issue 3(2018)
• Page Start: 233
• Page End: 247
• Publication Date: 2018-09-02
• Subjects: suffix tree -- chords -- improvisation -- decomposition -- chord progression -- open music; F1.1 -- F4.3; Music theory -- Periodicals; Music -- Mathematical models -- Periodicals; Music -- Mathematics -- Periodicals; 781.2
• DOI: 10.1080/17459737.2018.1538394
• Languages: English
• ISSNs: 1745-9737

Abstract

Abstract : Technology nowadays takes an increasing part of "creativity" in live music software such as theOMax-ImproteK-Djazz improvisation environment. Specifically, Djazz implements techniques for indexing and creating improvisations using a given chord progression. It relies on a database that we call a dictionary, storing musical sequences (audio or MIDI) associated with known chord changes. We define an improvisation on a given chord progression x as a sequence obtained by concatenating musical phrases identified with factors of x that can be found in the dictionary. Given a query sequence x and a dictionary D, we present an algorithm that finds an improvisation on x with respect to D . We use the suffix tree data structure to index D and then produce a graph formulation of the problem in order to find a suitable improvisation in linear time, with respect to the length of x .