Introduction to the Modeling and Analysis of Complex Systems

196 CHAPTER 11. CELLULAR AUTOMATA I: MODELINGnextconfig[x, y] = 1 if count >= 4 else 0config, nextconfig = nextconfig, configNote the swapping of config and nextconfig at the end. This is precisely the sametechnique that we did for the simulation of multi-variable dynamical systems in the earlierchapters.By putting all the above codes together, the completed simulator code in its entiretylooks like this:Code 11.5: panic-ca.pyimport matplotlibmatplotlib.use(’TkAgg’)from pylab import *n = 100 # size of space: n x np = 0.1 # probability of initially panicky individualsdef initialize():global config, nextconfigconfig = zeros([n, n])for x in xrange(n):for y in xrange(n):config[x, y] = 1 if random() < p else 0nextconfig = zeros([n, n])def observe():global config, nextconfigcla()imshow(config, vmin = 0, vmax = 1, cmap = cm.binary)def update():global config, nextconfigfor x in xrange(n):for y in xrange(n):count = 0for dx in [-1, 0, 1]:for dy in [-1, 0, 1]:count += config[(x + dx) % n, (y + dy) % n]