This program uses a simple, highly parallel evolutionary algorithm to evolve computer programs in my language sbrain.
If you're looking to run the generated programs, take a look at sbic.
It is quite effective at evolving relatively simple algorithms. It is invoked with cargo run --release <config file>, where the config file looks like this:
mutations_per_generation = 3
initial_program_length = 8
max_runtime = 128
population_size = 32
inputs = [ [1], [2], [999]]
targets = [[1, 2, 3], [2, 3, 4], [999, 1000, 1001]]
This is the specification for a program that starts at the input, and prints the next two consecutive numbers. A sample run from this example is:
Generation 1 Cost 5079: .Sa.s-^a
Generation 2 Cost 2013: ..S,.s-^a
Generation 26 Cost 1011: ,..zS,.s-^a
Generation 30 Cost 6: ,..zS+.s-^a
Generation 53 Cost 3: ,..+S+.s-^a
Generation 101 Cost 0: ,.*+.+.s-^a
Program found after 101 tries.
,.*+.+.s-^a
Ran for 100 cycles and did not halt
[1] -> ,.*+.+.s-^a -> [1, 2, 3]
Ran for 100 cycles and did not halt
[2] -> ,.*+.+.s-^a -> [2, 3, 4]
Ran for 100 cycles and did not halt
[999] -> ,.*+.+.s-^a -> [999, 1000, 1001]
The optimal program, of course, is ,.+.+..
There are a number of sample configurations in sample-configs/. Try them out!
Note also that the option legacy = true can be added to the config file to force the algorithm to use only the
original 8 Brainf*** instructions. For instance:
Generation 1 Cost 2013: +,.,.--,,.
Generation 3 Cost 1011: ]+>,[.[.[>.
Generation 7 Cost 12: <<,+.++..
Generation 8 Cost 6: >,..+.
Generation 9 Cost 3: <<-,.++..
Generation 1675 Cost 0: <-<---+,.+.+.
Program found after 1675 tries.
<-<---+,.+.+.
Ran for 128 cycles and did not halt
[1] -> <-<---+,.+.+. -> [1, 2, 3]
Ran for 128 cycles and did not halt
[2] -> <-<---+,.+.+. -> [2, 3, 4]
Ran for 128 cycles and did not halt
[999] -> <-<---+,.+.+. -> [999, 1000, 1001]