In this paper we describe how we used the logic-based probabilistic
programming language PRISM to conduct a systematic comparison
of several probabilistic models of symbolic music, including 0th and
1st order Markov models over pitches and intervals, and a probabilistic
grammar with two parameterisations. Using PRISM allows us to take
advantage of variational Bayesian methods for assessing the goodness of
fit of the models. When applied to a corpus of Bach chorales and the Essen
folk song collection, we found that, depending on various parameters, the
probabilistic grammars sometimes but not always out-perform the simple
Markov models. Examining how the models perform on smaller subsets
of pieces, we find that the simpler Markov models do out-perform the
best grammar-based model at the small end of the scale
