In a previous post, we introduced a library for performing arithmetic operations with arbitrary precision, and in this update we optimized the multiplication algorithm using the Fast Fourier Transform factorization.

One of my favourite problems in classical mechanics is the planetary motion, and one of my first attempts to solve it with computer algorithms dates from my early teens. My first approach was written in BASIC, and the results were completely wrong, as I didn’t know enough about the underlying maths. Subsequent attempts produced good results once I knew some basics of differential calculus during my high-school years.

My first steps in computer programming were with an old ZX Spectrum, like many other people of my generation. Following a natural order, Sinclair BASIC was the first language I dealt with, but quite often the hardware limitations forced me to move to the Z80 assembly language. A common practice was to code some “time critical” routines - like some graphic routines - in assembly to avoid many of the bottlenecks.

We introduced in a previous post a library for operating with arbitrarily big numbers, where we implemented some basic arithmetic operations, like addition, multiplication and division.

I decided to write this small library in 2000, after watching a rerun of “The Simpsons” episode “Treehouse of Horror VI”.

In this post I will propose a way to solve a sudoku puzzle with a computer program, trying to find all the puzzle solutions in an efficient way using an algorithm based on reduction of Uncertainty.