Successive generations of a celular automaton using rule 30.

automaton_rule_30.py

#!/usr/bin/python2
# Author: Hugo Guiroux: http://hugoguiroux.blogspot.fr/

import sys
from PIL import Image
import random

# The output image (bmp)
img_name = "wolf.bmp"

# Number of generation
if len(sys.argv) < 2:
    print "Usage: %s number_of_generation [random_fault]"%(sys.argv[0])
    exit(0)

generation = int(sys.argv[1])
width = generation * 2 + 1

randomize = True
if len(sys.argv) > 2:
    randomize = int(sys.argv[2]) == 1

# Information for user
print "Doing %d generation (length = %d)"%(generation, width)
if not randomize: print "Non",
print "Randomized first generation, generating %s"%img_name

# For now use array
cur_gen = [0 for k in range(width)]
next_gen = [0 for k in range(width)]

# Mark the center one
middle = int(width / 2)

# First generation
if randomize:
    for i in range(random.randint(0, width - 1)):
        cur_gen[random.randint(0, width - 1)] = 1
else:
    cur_gen[middle] = 1

# Declare rule: 0 = white, 1 = black
rules = {}

# Rule 30
rules[(0, 0, 0)] = 0
rules[(0, 0, 1)] = 1
rules[(0, 1, 0)] = 1
rules[(0, 1, 1)] = 1
rules[(1, 0, 0)] = 1
rules[(1, 0, 1)] = 0
rules[(1, 1, 0)] = 0
rules[(1, 1, 1)] = 0

# Create image
img = Image.new('1', (width, generation + 1), 'white')

def print_gen(gen, img, y):
    global generation, width
    for k in range(width):
        if generation < 50:
            print gen[k],

        # Print only black pixel, img.putpixel is CPU time consuming
        if gen[k] == 1:
            img.putpixel((k, y), 1 - gen[k])

    if generation < 50: print

# Generate and print
for cur in range(generation):
    # Print current line
    print_gen(cur_gen, img, cur)

    # Big automata, show progress
    if generation >= 50:
        print "%s%d/%d"%("\r"*20, cur+1, generation),

    # Shift for first row
    cur += 1

    # Compute next line
    for pos in range(width): #if non randomize,
                             # xrange(middle - cur, middle + cur + 1) is suffisant
        prev_cell = 0 if pos == 0 else cur_gen[pos - 1]
        next_cell = 0 if pos == width - 1 else cur_gen[pos + 1]

        next_gen[pos] = rules[(prev_cell, cur_gen[pos], next_cell)]

    # Switch gen
    cur_gen = next_gen[:]

# Print last generation
print_gen(cur_gen, img, generation)
img.save(img_name, "BMP")