The athenaCL system is a software tool for creating musical structures. Music is rendered as a polyphonic event list, or an EventSequence object. This EventSequence can be converted into diverse forms, or OutputFormats, including scores for the Csound synthesis language, Musical Instrument Digital Interface (MIDI) files, and other specialized formats. Within athenaCL, Orchestra and Instrument models provide control of and integration with diverse OutputFormats. Orchestra models may include complete specification, at the code level, of external sound sources that are created in the process of OutputFormat generation.
The athenaCL system features specialized objects for creating and manipulating pitch structures, including the Pitch, the Multiset (a collection of Pitches), and the Path (a collection of Multisets). Paths define reusable pitch groups. When used as a compositional resource, a Path is interpreted by a Texture object (described below).
The athenaCL system features three levels of algorithmic design. The first two levels are provided by the ParameterObject and the Texture. The ParameterObject is a model of a low-level one-dimensional parameter generator and transformer. The Texture is a model of a multi-dimensional generative musical part. A Texture is controlled and configured by numerous embedded ParameterObjects. Each ParameterObject is assigned to either event parameters, such as amplitude and rhythm, or Texture configuration parameters. The Texture interprets ParameterObject values to create EventSequences. The number of ParameterObjects in a Texture, as well as their function and interaction, is determined by the Texture's parent type (TextureModule) and Instrument model. Each Texture is an instance of a TextureModule. TextureModules encode diverse approaches to multi-dimensional algorithmic generation. The TextureModule manages the deployment and interaction of lower level ParameterObjects, as well as linear or non-linear event generation. Specialized TextureModules may be designed to create a wide variety of musical structures.
The third layer of algorithmic design is provided by the Clone, a model of the multi-dimensional transformative part. The Clone transforms EventSequences generated by a Texture. Similar to Textures, Clones are controlled and configured by numerous embedded ParameterObjects.
Each Texture and Clone creates a collection of Events. Each Event is a rich data representation that includes detailed timing, pitch, rhythm, and parameter data. Events are stored in EventSequence objects. The collection all Texture and Clone EventSequences is the complete output of athenaCL. These EventSequences are transformed into various OutputFormats for compositional deployment.
For general information on computer aided algorithmic composition and generative music systems, see the resources listed here and in References (Ariza 2005b, 2009a).
The athenaCL system has been under development since June 2000. The software is cross platform, developed under an open-source license, and programmed in the Python language. An interactive command-line interface provides an easy-to-use environment for beginners and a quick reference for advanced users. The complete functionality of the system is alternatively available as a scriptable batch processor or as a programmable Python extension library.