Based on the algorithms originally published by E. Oran Brigham "The Fast Fourier Transform" 1973, in ALGOL60 and FORTRAN. Originally written in the summer of 2008 during my holidays in Sardinia.
This is a public domain implementation completely free of charge. I only ask to cite me and send me a link to your work if you're using this.
Have fun with FFTs! They are a great source of inspiration, and when you start learning about these kind of math operators you'll find them everywhere.
Orlando