[Kory] has been writing genetic algorithms for a few months now. This in itself isn’t anything unique or exceptional, except for what he’s getting these genetic algorithms to do. [Kory] has been using genetic algorithms to write programs in Brainfuck. Yes, it’s a computer programming a computer. Be thankful Skynet is 18 years late.
When we first saw [Kory]’s work, he had programmed a computer to write and run its own programs in Brainfuck. Although the name of the language [Kory] chose could use some work, it’s actually the ideal language for computer-generated programs. With only eight commands, each consisting of a single character, it greatly reduces the overhead of what any genetic algorithm must produce and what a fitness function must evaluate.
There was one shortcoming to [Kory]’s initial efforts: functions. It’s relatively easy to get a program to say Hello World, but to do something complex, you’re going to need something like a macro or a function. Brainfuck, it its most simple form, doesn’t support functions. This throws a wrench in [Kory]’s plan to have his computer programming computer grow smarter and get over local minima in its genetic algorithms.
The solution to this problem was the creation of a new dialect of Brainfuck [Kory] calls BrainPlus. This takes the best parts of Extended Brainfuck and adds a command that basically serves as a break statement.
With this, [Kory]’s self programming computer can develop more complex programs. Already it has created a program to generate the first few numbers of the Fibonacci sequence. It only goes up to 233 because 255 is the maximum value for a byte, and the program itself took seven hours to generate. It does, however, work. Other programs generated with the new Brainplus functions include reciting 99 bottles on the wall and a program that multiples two values.
Even though [Kory]’s computer is spending a long time to generate these programs, given enough time, there’s really not much this program can’t do. Brainfuck, and [Kory]’s Brainplus, are Turing complete, so that given infinite memory and time it can compute anything. With the new addition of functions, it can compute anything faster.
All the code for [Kyle]’s GA is available on Github.