Post-Tonal Theory Calculator is a musical set theory analysis tool and compositional aid developed for iOS. Using the app, you can define pitch class sets, then analyze and perform various musical set theory operations on the sets.

For pitch sets you define, the app will:

- Calculate Normal Form and Prime Form
- Display the Forte Number
- Calculate the interval class vector
- Show transposed and inverted sets
- Display a set matrix
- Sort, invert or complement the set
- Play the notes of the set as a melody or chord, in the style of a piano or violin

The app also includes a comprehensive written overview of musical set theory. Composers like Arnold Schoenberg, Alban Berg and Anton Webern employed set theory techniques to organize the pitch content of their works.

### For Developers

The app was originally developed as a Java applet and known as the “Java Set Theory Machine.” You can download the original applet source code here, which includes Java classes for defining and manipulating pitch sets, interval vectors and Forte Numbers:

- SetTheoryCalculator.zip (122 kb)