Evaluating Mappings for Cellular Automata Music

We discuss the importance of choosing the right mapping for music composition generated from underlying ALife and emergent algorithms. Emergent algorithms are popular with composers both because their visual beauty inspires the composer, and because they can generate complexity from simple algorithm rules. Simple mappings to MIDI are preferred as they give a composer more control and predictability. However the wrong simple mapping may produce trivial music, and can fail to capture the visual aesthetic of the emergent phenomena in the music. Furthermore the mappings need some method of evaluation. To illustrate these issues we use the example of the Game of Life (GL). A polar co-ordinate mapping is introduced and we argue it is superior to previous GL mappings when both its simplicity and its visualaesthetic capture is considered. This mapping is evaluated by comparing it to linear mappings using Zipf’s Law and using a basic measure of structurality.