For interactive analyzing cellular automata you can use Python. Rule 30 is an easy example. It is a two state CA. To calculate the next value for the cell q you can use this expression: (p xor (q or r)), where "xor" and "or" are bitwise binary operators and p is the cell left to q and r is the cell right to q. The following Python class calculates one line for Rule 30:

from Numeric import * class Rule30: def __init__(self, length): # create arrays self.current = zeros(length, Int) self.workspace = zeros(length - 2, Int) # create slices self.left = self.current[:-2] self.right = self.current[2:] def step(self): # calculate the new values using bitwise operators self.workspace[:] = self.left ^ (self.current[1:-1] | self.right) # update current self.current[1:-1] = self.workspace

Then you can use Tkinter and the Python Image Library to display some steps of the automaton:

from Tkinter import * from ImageTk import PhotoImage import Image # create the Rule 30 object and init the middle to 1 length = 500 rule30 = Rule30(length) rule30.current[length / 2] = 1 # create the image array lines = length / 2 imageArray = zeros((lines, length), Int) for step in range(lines): imageArray[step, :] = rule30.current rule30.step() # init tk root = Tk() root.title('Rule 30') # convert the image array into a PIL image and display it img = Image.fromstring('L', (length, lines), ((1 - imageArray) * 255).astype(Int8).tostring()) photo = PhotoImage(image = img) label = Label(image = photo) label.pack() root.mainloop()

Here's the full source-code, with the rule30 definition: rule30image.py

You will see this picture:

If you want to count the number of 1's in each line, you can write something like this:

# create the Rule 30 object and init the middle to 1 length = 10000 rule30 = Rule30(length) rule30.current[length / 2] = 1 # print the number of '1's for all automaton steps for step in range(length / 2): print sum(rule30.current) rule30.step()

Here's the full source-code, with the rule30 definition: rule30.py

You can redirect to output to a file (wait some minutes for all 5000 steps):

python rule30.py > ones.txt

Then you can paste ones.txt to a spreadsheet and plotting some charts.

All 5000 values (ones.txt):

An interval near the end:

This was tested with Python-2.2.2.exe, Python Imaging Library 1.1.2 for Python 2.2b1 and Numeric-23.0.

9. March 2003, Frank Buß