net-majority.py

import pycxsimulator
from pylab import *

import networkx as nx

def initialize():
    global g, nextg
    g = nx.karate_club_graph()
    g.pos = nx.spring_layout(g)
    for i in g.nodes:
        g.nodes[i]['state'] = 1 if random() < .5 else 0
    nextg = g.copy()
    nextg.pos = g.pos
    
def observe():
    global g, nextg
    cla()
    nx.draw(g, cmap = cm.bwr, vmin = 0, vmax = 1,
            node_color = [g.nodes[i]['state'] for i in g.nodes],
            pos = g.pos)

def update():
    global g, nextg
    for i in g.nodes:
        count = g.nodes[i]['state']
        for j in g.neighbors(i):
            count += g.nodes[j]['state']
        ratio = count / (g.degree(i) + 1.0)
        nextg.nodes[i]['state'] = 1 if ratio > .5 \
                                 else 0 if ratio < .5 \
                                 else 1 if random() < .5 else 0
    g, nextg = nextg, g

pycxsimulator.GUI().start(func=[initialize, observe, update])