by Paul Thompson - nossidge@gmail.com - tilde.town/~nossidge
One dimensional cellular automata. Supports multiple cell states. Output to stdout and .png image.
This is so unfinished it's just like wow.
http://mathworld.wolfram.com/ElementaryCellularAutomaton.html
A tutorial for the console.
Let's create an output using just the -x and -y options to specify the size:
$ automata.rb -x37 -y7
1000000000000000000000000000000000000
0100000000000000000000000000000000000
1010000000000000000000000000000000000
0001000000000000000000000000000000000
0010100000000000000000000000000000000
0100010000000000000000000000000000000
1010101000000000000000000000000000000
0000000100000000000000000000000000000
This writes a single true '1' cell at the leftmost character of the first row, and applies a random rule to generate 6 more generations. The random rule used for this is rule 146. Each time a automaton is generated, the rule number is saved to a file called ~rules.txt so you can see which rule was most recently used.
We can use the -u option to choose a specific rule, so let's use -u146 so we can compare future output using the same rule. We will now use the -c option to centre the initial '1' cell in the middle of the input row.
$ automata.rb -x37 -y7 -u146 -c
0000000000000000001000000000000000000
0000000000000000010100000000000000000
0000000000000000100010000000000000000
0000000000000001010101000000000000000
0000000000000010000000100000000000000
0000000000000101000001010000000000000
0000000000001000100010001000000000000
0000000000010101010101010100000000000
The default output symbols are 01234... for each cell state. But we can overwrite this using the -s option. Let's make all zero states a space, and all one states a lowercase O.
$ automata.rb -x37 -y7 -u146 -c -s' o'
o
o o
o o
o o o o
o o
o o o o
o o o o
o o o o o o o o
That looks pretty cool. You can also use the -v option to flip the output so that the oldest generations are displayed last:
$ automata.rb -x37 -y7 -u146 -c -s' o' -v
o o o o o o o o
o o o o
o o o o
o o
o o o o
o o
o o
o
The -t option is used to add Y-axis symmetry to the output:
$ automata.rb -x37 -y7 -u146 -c -s' o' -t
o
o o
o o
o o o o
o o
o o o o
o o o o
o o o o o o o o
o o o o
o o o o
o o
o o o o
o o
o o
o
$ automata.rb -x37 -y7 -u146 -c -s' o' -tv
o o o o o o o o
o o o o
o o o o
o o
o o o o
o o
o o
o
o o
o o
o o o o
o o
o o o o
o o o o
o o o o o o o o
Instead of using a single one cell as the initial state, we can specify whatever state we want, by using the -i option. The -c option works here as well, so we can use it to write '1000001' to the centre of the initial state:
$ automata.rb -x37 -y7 -u146 -c -s' o' -i'1000001'
o o
o o o o
o o o o
o o o o o o
o o o o
o o o o o o
o o o o o o o o
o o o o o o
Or you could just let it randomly create an initial state, with the -r option:
$ automata.rb -x37 -y7 -u146 -c -s' o' -r
oooo oo o o o ooo o o o o o o
o oo o o o o o o
o o o o o o o o
o o oo o o o o o o o o
o oo o o o o o
o o o o o o o
o o o o o o o o o o
o o o o o o o
The -N option lets you constrain the randomised initial state to just a few cells, leaving the rest with state zero. So to randomise just the centremost 15 cells:
$ automata.rb -x37 -y7 -u146 -c -s' o' -r -N15
o o oo o
o o o oo o o o
o oo o
o o o o o o
o o o oo o o o
o o o o o o o o
o oo o o o
o o o o o o o o
And you can use the -p option to specify the probablility of each option. This chooses state one 90% of the time, and zero the remainder:
$ automata.rb -x37 -y7 -u146 -c -s' o' -r -p'0111111111'
o oooooooooo ooooo oooooooo ooooooooo
oooooooo ooo oooooo ooooooo
o oooooo o o o o o oooo o o ooooo o
o oooo oo ooo
o o o oo o o o o o o
o o oo o o o
o o o o o o o o
o o o o o o o
I'm going to use the initial state of that last example to show the -w option. This wraps the screen, so that the far-left cell will take into account the value of the far-right cell and vice versa.
$ automata.rb -x37 -y7 -u146 -c -s' o' -r -i'1 1111111111 11111 11111111 111111111' -w
o oooooooooo ooooo oooooooo ooooooooo
oooooooo ooo oooooo oooooooo
o o oooooo o o o o o oooo o o oooooo
oooo oo oooo
o oo o o o o oo o
o o o oo o o o
o o o o o o o o o o
o o o o o o o o
Now you can start to see the pretty, chaotic patterns that can be generated with just these simple rules!