A small Haskell tool that parses a list of songs and their chord progressions and outputs a matrix representing a weighted undirected graph of all the progressions in the songs, each weight representing the similarity of the two progressions. The said graph can then be viewed in a program like Gephi to get visual representation of the data and draw conclusions.
An example graph created using Gephi with the "ForceAtlas 2" layout:
To create a "data.csv" in your working directory, run:
$ runhaskell Main.hs path/to/database"database" being the list of songs and their corresponding chord progressions.