The Implementation of chronotonic similarity within an applet Ludger Hofmann-Engl Development - Croydon Family Groups hofmann-engl@chameleongroup.org.uk Abstract The term chronotonic similarity/distance was first introduced by Hofmann-Engl in the late 1990ths in order to describe the phenomenon of what might be called rhythmic similarity, and although it has been used within a number of studies and in particular in order to classify flamenco meters, it appears that no attempt has been undertaken so far to produce an application which would allow potential users to compute the chronotonic similarity via a user friendly interface. This paper introduces the reader to the concept of chronotonic similarity and discusses the method which was used to implement this similarity measure within an applet. The paper also touches on issues of ongoing development and the integration of the software into other applications such as automated composers, automated analysis and search engines. 1. Introduction During the 90ths, Hofmann-Engl realized that rhythmic, or to use his terminology, chronotonic similarity could only be computed if rhythms were to be represented in atomic notation in analogy to a concept introduced by Gustafson (1987, 1988) in the context of phonetics. In more recent years, the concept of chronotonic similarity or chronotonic distance has been successfully used in the attempt to classify flamenco music (compare J. M. Diáz-Báñez, G. Farigu, F. Gómez, D. Rappaport & G. T. Toussaint, 2004). In a very recent study by Thul & Toussaint (2008), the chronotonic distance was successfully used to analyse African Timeliens and North Indian Talas. However, due to some mathematical difficulties and the need of computer aided computation has hindered a more comprehensive application and evaluation of chronotonic similarity and its development. Therefore, the author decided to program an applet which allows for the effective and user friendly computation of chronotonic similarity. The applet is located at: www.chameleongroup.org.uk/software/c- chain.html This paper will explain the concept of atomic notation and the chronotonic similarity based upon it. It then will strive to explain how the chronotonic similarity has been implemented within a java program and will conclude with a brief outlook on potential future developments and implementations. 2. Atomic Notation In order to introduce atomic notation, two methods are available. Firstly, a formal mathematical introduction could be given and secondly a more practical and example- based dissemination. The author decided to adopt the latter method. Let us consider the two following rhythms: rhythm 1: 1/4 ½ 1/8 1/8 ½