Understanding Schönhage-Strassen algorithm (huge integer multiplication)

Question

I need to multiply several 1000s digits long integers as efficiently as possible in Python. The numbers are read from a file.

I am trying to implement the Schönhage-Stra

Answer 1

Chapter 4.3.3 of Knuth's TAOCP describes it and also has some FFT pseudocode in other chapters that could be used for this.