Musical Virtuosity and Creativity - Computers and Creativity - page 138

Fig. 5.29 A phrase generated with an intentional score consisting of 'chromatic' for the first six
beats, and 'arpeggiated' for the next six on the same chord sequence, and one random transform.
The melody generated fits almost perfectly the constraints
Fig. 5.30 A phrase generated on the chord sequence as Fig. 5.7 , with three intentionally chosen
side-slips and three subjective biases
line with commands at every beat. An improvisation can be seen as an interpretation
of this score.
The intentional score represents the 'arbitrary' portion of chorus generation, so
it cannot be generated automatically. In practice, it can be set randomly, or using an
interface, e.g. gestural to produce the various commands in real time, as described
in the next section.
An interesting application of concept of intentional score is to induce such an
intentional score from an existing chorus , to generate a new improvisation with the
same structure . We illustrate this idea using the chorus shown in Fig. 5.7 . Of course,
there is not a single way to infer the intentional score used by John McLaughlin.
The score we consider uses solely 'target pitch' subjective biases, extracted from
the actual mean pitches of the various beats in John McLaughlin's phrase. It looks
as Fig. 5.31 .