The program identifies musical fragments that are repeated in the same composition or other compositions in a collection. Fragments consisting of just a few notes may not be significant, since their occurrence is likely to be purely random. Longer fragments consisting of 6 or more notes are less likely to repeat accidentally and many repetitions are typically found in a particular composition. If these fragments also reappear in other compositions by the same composer such repeating patterns may be part of the composer's style, or the composer may unconsciously use these patterns in certain situations. One finds the same pattern used by other composers but in a different manner. The following examples illustrate how this program can be used to study the characteristics of some composers.
J.S. Bach and D. Scarlatti were both prolific composers of music for the harpsichord. Using computer analysis, one can trace how a simple pattern of notes appears in different compositions. For a start, consider the opening theme of Bach's Two-part Invention 1 (BWV772). BWV772 This turns out to be a motif of the invention and recurs more than a dozen times in different transpositions. Now compare this fragment with BWV780 from Bach's Two-part Invention 9 (BWV780), which sounds quite similar. In fact, if you listen to the beginning of Invention 1 BWV772 and the end of Invention 9 BWV780 they both complement each other. This theme also recurs near the closing of Invention 10 BWV781. It also occurs in Duet 4 (BWV805), English Suite 2,3, 6, French Suite 1, and many more places, including Bach's chorale Danket dem Herrn heut und allzeit BWV6.
Scarlatti uses this fragment in a different manner, yielding a different impression. In Sonata K.24 the fragment sounds like this and is used as a transition element between two phrases, as illustrated here. The fragment is also found in a few other sonatas, such as Scarlatti K.404 , where it is also used like a conjunction.
Haydn uses this pattern in the third movement of Sonata 16.
Unlike J.S. Bach, D. Scarlatti wrote sonatas that are variable in character and do not carry any uniform theme. If one looks for repeating patterns in his work, one finds mainly ascending and descending scale sequences and arpeggios. For example, in K. 1, one encounters a broken ascending scale. This artifice is rarely used by his other contemporaries, but it appears again in K. 19, in several places in K. 230, in a couple of places in K.311 and in a few other sonatas.
There are a few places where Scarlatti reuses the same thematic pattern. For example, the note sequence occurs in the context K. 140 and also in K.61 as a variation.